SCIX IMPACT ON DWPF CPC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopman, D.

2011-07-14

A program was conducted to systematically evaluate potential impacts of the proposed Small Column Ion Exchange (SCIX) process on the Defense Waste Processing Facility (DWPF) Chemical Processing Cell (CPC). The program involved a series of interrelated tasks. Past studies of the impact of crystalline silicotitanate (CST) and monosodium titanate (MST) on DWPF were reviewed. Paper studies and material balance calculations were used to establish reasonable bounding levels of CST and MST in sludge. Following the paper studies, Sludge Batch 10 (SB10) simulant was modified to have both bounding and intermediate levels of MST and ground CST. The SCIX flow sheetmore » includes grinding of the CST which is larger than DWPF frit when not ground. Nominal ground CST was not yet available, therefore a similar CST ground previously in Savannah River National Laboratory (SRNL) was used. It was believed that this CST was over ground and that it would bound the impact of nominal CST on sludge slurry properties. Lab-scale simulations of the DWPF CPC were conducted using SB10 simulants with no, intermediate, and bounding levels of CST and MST. Tests included both the Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) cycles. Simulations were performed at high and low acid stoichiometry. A demonstration of the extended CPC flowsheet was made that included streams from the site interim salt processing operations. A simulation using irradiated CST and MST was also completed. An extensive set of rheological measurements was made to search for potential adverse consequences of CST and MST and slurry rheology in the CPC. The SCIX CPC impact program was conducted in parallel with a program to evaluate the impact of SCIX on the final DWPF glass waste form and on the DWPF melter throughput. The studies must be considered together when evaluating the full impact of SCIX on DWPF. Due to the fact that the alternant flowsheet for DWPF has not been selected, this study did not consider the impact of proposed future alternative DWPF CPC flowsheets. The impact of the SCIX streams on DWPF processing using the selected flowsheet need to be considered as part of the technical baseline studies for coupled processing with the selected flowsheet. In addition, the downstream impact of aluminum dissolution on waste containing CST and MST has not yet been evaluated. The current baseline would not subject CST to the aluminum dissolution process and technical concerns with performing the dissolution with CST have been expressed. Should this option become feasible, the downstream impact should be considered. The main area of concern for DWPF from aluminum dissolution is an impact on rheology. The SCIX project is planning for SRNL to complete MST, CST, and sludge rheology testing to evaluate any expected changes. The impact of ground CST transport and flush water on the DWPF CPC feed tank (and potential need for decanting) has not been defined or studied.« less

ELIMINATION OF THE CHARACTERIZATION OF DWPF POUR STREAM SAMPLE AND THE GLASS FABRICATION AND TESTING OF THE DWPF SLUDGE BATCH QUALIFICATION SAMPLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amoroso, J.; Peeler, D.; Edwards, T.

2012-05-11

A recommendation to eliminate all characterization of pour stream glass samples and the glass fabrication and Product Consistency Test (PCT) of the sludge batch qualification sample was made by a Six-Sigma team chartered to eliminate non-value-added activities for the Defense Waste Processing Facility (DWPF) sludge batch qualification program and is documented in the report SS-PIP-2006-00030. That recommendation was supported through a technical data review by the Savannah River National Laboratory (SRNL) and is documented in the memorandums SRNL-PSE-2007-00079 and SRNL-PSE-2007-00080. At the time of writing those memorandums, the DWPF was processing sludge-only waste but, has since transitioned to a coupledmore » operation (sludge and salt). The SRNL was recently tasked to perform a similar data review relevant to coupled operations and re-evaluate the previous recommendations. This report evaluates the validity of eliminating the characterization of pour stream glass samples and the glass fabrication and Product Consistency Test (PCT) of the sludge batch qualification samples based on sludge-only and coupled operations. The pour stream sample has confirmed the DWPF's ability to produce an acceptable waste form from Slurry Mix Evaporator (SME) blending and product composition/durability predictions for the previous sixteen years but, ultimately the pour stream analysis has added minimal value to the DWPF's waste qualification strategy. Similarly, the information gained from the glass fabrication and PCT of the sludge batch qualification sample was determined to add minimal value to the waste qualification strategy since that sample is routinely not representative of the waste composition ultimately processed at the DWPF due to blending and salt processing considerations. Moreover, the qualification process has repeatedly confirmed minimal differences in glass behavior from actual radioactive waste to glasses fabricated from simulants or batch chemicals. In contrast, the variability study has significantly added value to the DWPF's qualification strategy. The variability study has evolved to become the primary aspect of the DWPF's compliance strategy as it has been shown to be versatile and capable of adapting to the DWPF's various and diverse waste streams and blending strategies. The variability study, which aims to ensure durability requirements and the PCT and chemical composition correlations are valid for the compositional region to be processed at the DWPF, must continue to be performed. Due to the importance of the variability study and its place in the DWPF's qualification strategy, it will also be discussed in this report. An analysis of historical data and Production Records indicated that the recommendation of the Six Sigma team to eliminate all characterization of pour stream glass samples and the glass fabrication and PCT performed with the qualification glass does not compromise the DWPF's current compliance plan. Furthermore, the DWPF should continue to produce an acceptable waste form following the remaining elements of the Glass Product Control Program; regardless of a sludge-only or coupled operations strategy. If the DWPF does decide to eliminate the characterization of pour stream samples, pour stream samples should continue to be collected for archival reasons, which would allow testing to be performed should any issues arise or new repository test methods be developed.« less

SALTSTONE VAULT CLASSIFICATION SAMPLES MODULAR CAUSTIC SIDE SOLVENT EXTRACTION UNIT/ACTINIDE REMOVAL PROCESS WASTE STREAM APRIL 2011

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eibling, R.

Savannah River National Laboratory (SRNL) was asked to prepare saltstone from samples of Tank 50H obtained by SRNL on April 5, 2011 (Tank 50H sampling occurred on April 4, 2011) during 2QCY11 to determine the non-hazardous nature of the grout and for additional vault classification analyses. The samples were cured and shipped to Babcock & Wilcox Technical Services Group-Radioisotope and Analytical Chemistry Laboratory (B&W TSG-RACL) to perform the Toxic Characteristic Leaching Procedure (TCLP) and subsequent extract analysis on saltstone samples for the analytes required for the quarterly analysis saltstone sample. In addition to the eight toxic metals - arsenic, barium,more » cadmium, chromium, mercury, lead, selenium and silver - analytes included the underlying hazardous constituents (UHC) antimony, beryllium, nickel, and thallium which could not be eliminated from analysis by process knowledge. Additional inorganic species determined by B&W TSG-RACL include aluminum, boron, chloride, cobalt, copper, fluoride, iron, lithium, manganese, molybdenum, nitrate/nitrite as Nitrogen, strontium, sulfate, uranium, and zinc and the following radionuclides: gross alpha, gross beta/gamma, 3H, 60Co, 90Sr, 99Tc, 106Ru, 106Rh, 125Sb, 137Cs, 137mBa, 154Eu, 238Pu, 239/240Pu, 241Pu, 241Am, 242Cm, and 243/244Cm. B&W TSG-RACL provided subsamples to GEL Laboratories, LLC for analysis for the VOCs benzene, toluene, and 1-butanol. GEL also determines phenol (total) and the following radionuclides: 147Pm, 226Ra and 228Ra. Preparation of the 2QCY11 saltstone samples for the quarterly analysis and for vault classification purposes and the subsequent TCLP analyses of these samples showed that: (1) The saltstone waste form disposed of in the Saltstone Disposal Facility in 2QCY11 was not characteristically hazardous for toxicity. (2) The concentrations of the eight RCRA metals and UHCs identified as possible in the saltstone waste form were present at levels below the UTS. (3) Most of the inorganic species measured in the leachate do not exceed the MCL, SMCL or TW limits. (4) The inorganic waste species that exceeded the MCL by more than a factor of 10 were nitrate, nitrite and the sum of nitrate and nitrite. (5) Analyses met all quality assurance specifications of US EPA SW-846. (6) The organic species (benzene, toluene, 1-butanol, phenol) were either not detected or were less than reportable for the vault classification samples. (7) The gross alpha and radium isotopes could not be determined to the MCL because of the elevated background which raised the detection limits. (8) Most of the beta/gamma activity was from 137Cs and its daughter 137mBa. (9) The concentration of 137Cs and 90Sr were present in the leachate at concentrations 1/40th and 1/8th respectively than in the 2003 vault classification samples. The saltstone waste form placed in the Saltstone Disposal Facility in 2QCY11 met the SCHWMR R.61-79.261.24(b) RCRA metals requirements for a nonhazardous waste form. The TCLP leachate concentrations for nitrate, nitrite and the sum of nitrate and nitrite were greater than 10x the MCLs in SCDHEC Regulations R.61-107.19, Part I A, which confirms the Saltstone Disposal Facility classification as a Class 3 Landfill. The saltstone waste form placed in the Saltstone Disposal Facility in 2QCY11 met the R.61-79.268.48(a) non wastewater treatment standards.« less

Solubility Control of Technetium Release from Saltstone by Tc02•xH20

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cantrell, Kirk J.; Williams, Benjamin D.

2013-11-12

Saltstone leaching experiments were conducted using a modified single-pass flow-through method under anoxic conditions. The analytical results of leachates collected from these experiments were evaluated using thermodynamic modeling to determine if the data were consistent with potential solubility controlling phases. The results demonstrate that technetium concentrations in water in contact with Saltstone under anoxic conditions is controlled by the solubility of TcO2•xH2O (likely TcO2•1.6H2O). In our system equilibrium solubility appears to have been reached within two weeks at a concentration of approximately 1.5 x 10-6 M. This concentration is likely to vary as the composition of Saltstone pore fluid evolvesmore » over time. As the pH goes from the initial high values (~12.5-13) to lower values, the solubility of technetium will decrease significantly. The thermodynamic data used to determine the solubility of TcO2•1.6H2O were taken from the tabulation of critically selected thermodynamic data determined by the Nuclear Energy Agency. Solid phase characterization to demonstrate the presence of TcO2•xH2O was not possible due to the low concentrations of technetium in our samples. Previous solid phase characterization studies with cementitious waste forms that were very similar to our Saltstone samples as well as reaction products derived from reductive immobilization of TcO4- by amorphous FeS clearly indicate the presence of TcO2 with varying degrees of hydration. Although, the presence of TcSx or other reduced technetium sulfide phases in our samples cannot be ruled out, release of technetium from Saltstone will be controlled by TcO2•1.6H2O because of its higher solubility. Our results clearly demonstrate that the release mechanism of technetium from Saltstone under reducing conditions is solubility controlled by TcO2•xH2O (likely TcO2•1.6H2O); however, distribution coefficients (Kds), that describe sorption and not solubility, were calculated for comparison with past literature values. After 84 days of reaction under anoxic conditions, the average Kd value for technetium was determined to be 610 mL/g. This value is similar to a value determined previously for a similar saltstone sample under reducing conditions at 56 days (712 ± 81 mL/g).« less

DWPF simulant CPC studies for SB8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopman, D. C.; Zamecnik, J. R.

2013-06-25

The Savannah River National Laboratory (SRNL) accepted a technical task request (TTR) from Waste Solidification Engineering to perform simulant tests to support the qualification of Sludge Batch 8 (SB8) and to develop the flowsheet for SB8 in the Defense Waste Processing Facility (DWPF). These efforts pertained to the DWPF Chemical Process Cell (CPC). Separate studies were conducted for frit development and glass properties (including REDOX). The SRNL CPC effort had two primary phases divided by the decision to drop Tank 12 from the SB8 constituents. This report focuses on the second phase with SB8 compositions that do not contain themore » Tank 12 piece. A separate report will document the initial phase of SB8 testing that included Tank 12. The second phase of SB8 studies consisted of two sets of CPC studies. The first study involved CPC testing of an SB8 simulant for Tank 51 to support the CPC demonstration of the washed Tank 51 qualification sample in the SRNL Shielded Cells facility. SB8-Tank 51 was a high iron-low aluminum waste with fairly high mercury and moderate noble metal concentrations. Tank 51 was ultimately washed to about 1.5 M sodium which is the highest wash endpoint since SB3-Tank 51. This study included three simulations of the DWPF Sludge Receipt and Adjustment Tank (SRAT) cycle and Slurry Mix Evaporator (SME) cycle with the sludge-only flowsheet at nominal DWPF processing conditions and three different acid stoichiometries. These runs produced a set of recommendations that were used to guide the successful SRNL qualification SRAT/SME demonstration with actual Tank 51 washed waste. The second study involved five SRAT/SME runs with SB8-Tank 40 simulant. Four of the runs were designed to define the acid requirements for sludge-only processing in DWPF with respect to nitrite destruction and hydrogen generation. The fifth run was an intermediate acid stoichiometry demonstration of the coupled flowsheet for SB8. These runs produced a set of processing recommendations for DWPF along with some data related to Safety Class documentation at DWPF. Some significant observations regarding SB8 follow: Reduced washing in Tank 51 led to an increase in the wt.% soluble solids of the DWPF feed. If wt.% total solids for the SRAT and SME product weren’t adjusted upward to maintain insoluble solids levels similar to past sludge batches, then the rheological properties of the slurry went below the low end of the DWPF design bases for the SRAT and SME. Much higher levels of dissolved manganese were found in the SRAT and SME products than in recent sludge batches. Closed crucible melts were more reduced than expected. The working hypothesis is that the soluble Mn is less oxidizing than assumed in the REDOX calculations. A change in the coefficient for Mn in the REDOX equation was recommended in a separate report. The DWPF (Hsu) stoichiometric acid equation was examined in detail to better evaluate how to control acid in DWPF. The existing DWPF equation can likely be improved without changing the required sample analyses through a paper study using existing data. The recommended acid stoichiometry for initial SB8 SRAT batches is 115-120% stoichiometry until some processing experience is gained. The conservative range (based on feed properties) of stoichiometric factors derived in this study was from 110-147%, but SRNL recommends using only the lower half of this range, 110-126% even after initial batches provide processing experience. The stoichiometric range for sludge-only processing appears to be suitable for coupled operation based on results from the run in the middle of the range. Catalytic hydrogen was detectable (>0.005 vol%) in all SRAT and SME cycles. Hydrogen reached 30-35% of the SRAT and SME limits at the mid-point of the stoichiometry window (bounding noble metals and acid demand).« less

Defining And Characterizing Sample Representativeness For DWPF Melter Feed Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shine, E. P.; Poirier, M. R.

2013-10-29

Representative sampling is important throughout the Defense Waste Processing Facility (DWPF) process, and the demonstrated success of the DWPF process to achieve glass product quality over the past two decades is a direct result of the quality of information obtained from the process. The objective of this report was to present sampling methods that the Savannah River Site (SRS) used to qualify waste being dispositioned at the DWPF. The goal was to emphasize the methodology, not a list of outcomes from those studies. This methodology includes proven methods for taking representative samples, the use of controlled analytical methods, and datamore » interpretation and reporting that considers the uncertainty of all error sources. Numerous sampling studies were conducted during the development of the DWPF process and still continue to be performed in order to evaluate options for process improvement. Study designs were based on use of statistical tools applicable to the determination of uncertainties associated with the data needs. Successful designs are apt to be repeated, so this report chose only to include prototypic case studies that typify the characteristics of frequently used designs. Case studies have been presented for studying in-tank homogeneity, evaluating the suitability of sampler systems, determining factors that affect mixing and sampling, comparing the final waste glass product chemical composition and durability to that of the glass pour stream sample and other samples from process vessels, and assessing the uniformity of the chemical composition in the waste glass product. Many of these studies efficiently addressed more than one of these areas of concern associated with demonstrating sample representativeness and provide examples of statistical tools in use for DWPF. The time when many of these designs were implemented was in an age when the sampling ideas of Pierre Gy were not as widespread as they are today. Nonetheless, the engineers and statisticians used carefully thought out designs that systematically and economically provided plans for data collection from the DWPF process. Key shared features of the sampling designs used at DWPF and the Gy sampling methodology were the specification of a standard for sample representativeness, an investigation that produced data from the process to study the sampling function, and a decision framework used to assess whether the specification was met based on the data. Without going into detail with regard to the seven errors identified by Pierre Gy, as excellent summaries are readily available such as Pitard [1989] and Smith [2001], SRS engineers understood, for example, that samplers can be biased (Gy's extraction error), and developed plans to mitigate those biases. Experiments that compared installed samplers with more representative samples obtained directly from the tank may not have resulted in systematically partitioning sampling errors into the now well-known error categories of Gy, but did provide overall information on the suitability of sampling systems. Most of the designs in this report are related to the DWPF vessels, not the large SRS Tank Farm tanks. Samples from the DWPF Slurry Mix Evaporator (SME), which contains the feed to the DWPF melter, are characterized using standardized analytical methods with known uncertainty. The analytical error is combined with the established error from sampling and processing in DWPF to determine the melter feed composition. This composition is used with the known uncertainty of the models in the Product Composition Control System (PCCS) to ensure that the wasteform that is produced is comfortably within the acceptable processing and product performance region. Having the advantage of many years of processing that meets the waste glass product acceptance criteria, the DWPF process has provided a considerable amount of data about itself in addition to the data from many special studies. Demonstrating representative sampling directly from the large Tank Farm tanks is a difficult, if not unsolvable enterprise due to limited accessibility. However, the consistency and the adequacy of sampling and mixing at SRS could at least be studied under the controlled process conditions based on samples discussed by Ray and others [2012a] in Waste Form Qualification Report (WQR) Volume 2 and the transfers from Tanks 40H and 51H to the Sludge Receipt and Adjustment Tank (SRAT) within DWPF. It is important to realize that the need for sample representativeness becomes more stringent as the material gets closer to the melter, and the tanks within DWPF have been studied extensively to meet those needs.« less

1QCY17 Saltstone waste characterization analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, F. C.

2017-07-25

In the first quarter of calendar year 2017, a salt solution sample was collected from Tank 50 on January 16, 2017 in order to meet South Carolina (SC) Regulation 61-107.19 Part I C, “Solid Waste Management: Solid Waste Landfills and Structural Fill – General Requirements” and the Saltstone Disposal Facility Class 3 Landfill Permit. The Savannah River National Laboratory (SRNL) was requested to prepare and ship saltstone samples to a United States Environmental Protection Agency (EPA) certified laboratory to perform the Toxicity Characteristic Leaching Procedure (TCLP) and subsequent characterization.

Crystallization in high level waste (HLW) glass melters: Savannah River Site operational experience

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, Kevin M.; Peeler, David K.; Kruger, Albert A.

2015-06-12

This paper provides a review of the scaled melter testing that was completed for design input to the Defense Waste Processing Facility (DWPF) melter. Testing with prototype melters provided the data to define the DWPF operating limits to avoid bulk (volume) crystallization in the un-agitated DWPF melter and provided the data to distinguish between spinels generated by refractory corrosion versus spinels that precipitated from the HLW glass melt pool. A review of the crystallization observed with the prototype melters and the full-scale DWPF melters (DWPF Melter 1 and DWPF Melter 2) is included. Examples of actual DWPF melter attainment withmore » Melter 2 are given. The intent is to provide an overview of lessons learned, including some example data, that can be used to advance the development and implementation of an empirical model and operating limit for crystal accumulation for a waste treatment and immobilization plant.« less

EVALUATION AND RECOMMENDATION OF SALTSTONE MIXER AUGER/PADDLES MATERIALS OF CONSTRUCTION FOR IMPROVED WEAR RESISTANCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J.; Torres, R.

2012-08-15

Wear and corrosion testing were conducted to evaluate alternate materials of construction for the Saltstone mixer auger and paddles. These components have been degraded by wear from the slurry processed in the mixer. Material test options included PVD coatings (TiN, TiCN, and ZrN), weld overlays (Stellite 12 and Ultimet) and higher hardness steels and carbides (D2 and tungsten carbide). The corrosion testing demonstrated that the slurry is not detrimental to the current materials of construction or the new candidates. The ASTM G75 Miller wear test showed that the high hardness materials and the Stellite 12 weld overlay provide superior wearmore » relative to the Astralloy and CF8M stainless steel, which are the current materials of construction, as well as the PVD coatings and Ultimet. The following recommendations are made for selecting new material options and improving the overall wear resistance of the Saltstone mixer components: A Stellite 12 weld overlay or higher hardness steel (with toughness equivalent to Astralloy) be used to improve the wear resistance of the Saltstone mixer paddles; other manufacturing specifications for the mixer need to be considered in this selection. The current use of the Stellite 12 weld overlay be evaluated so that coverage of the 316 auger can be optimized for improved wear resistance of the auger. The wear surfaces of the Saltstone mixer auger and paddles be evaluated so that laboratory data can be better correlated to actual service. The 2-inch Saltstone mixer prototype be used to verify material performance.« less

Ecological studies related to the construction of the Defense Waste Processing Facility on the Savannah River Site. Annual report, FY-1991 and FY-1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott, D.E.; Chazel, A.C.; Pechmann, J.H.K.

1993-06-01

The Defense Waste Processing Facility (DWPF) was built on the Savannah River Site (SRS) during the mid-1980`s. The Savannah River Ecology Laboratory (SREL) has completed 14 years of ecological studies related to the construction of the DWPF complex. Prior to construction, the 600-acre site (S-Area) contained a Carolina bay and the headwaters of a stream. Research conducted by the SREL has focused primarily on four questions related to these wetlands: (1) Prior to construction, what fauna and flora were present at the DWPF site and at similar, yet undisturbed, alternative sites? (2) By comparing the Carolina bay at the DWPFmore » site (Sun Bay) with an undisturbed control Carolina bay (Rainbow Bay), what effect is construction having on the organisms that inhabited the DWPF site? (3) By comparing control streams with streams on the periphery of the DWPF site, what effect is construction having on the peripheral streams? (4) How effective have efforts been to lessen the impacts of construction, both with respect to erosion control measures and the construction of ``refuge ponds`` as alternative breeding sites for amphibians that formerly bred at Sun Bay? Through the long-term census-taking of biota at the DWPF site and Rainbow Bay, SREL has begun to evaluate the impact of construction on the biota and the effectiveness of mitigation efforts. Similarly, the effects of erosion from the DWPF site on the water quality of S-Area peripheral streams are being assessed. This research provides supporting data relevant to the National Environmental Policy Act (NEPA) of 1969, the Endangered Species Act of 1973, Executive Orders 11988 (Floodplain Management) and 11990 (Protection of Wetlands), and United States Department of Energy (DOE) Guidelines for Compliance with Floodplain/Wetland Environmental Review Requirements (10 CFR 1022).« less

SME Acceptability Determination For DWPF Process Control (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.

2017-06-12

The statistical system described in this document is called the Product Composition Control System (PCCS). K. G. Brown and R. L. Postles were the originators and developers of this system as well as the authors of the first three versions of this technical basis document for PCCS. PCCS has guided acceptability decisions for the processing at the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) since the start of radioactive operations in 1996. The author of this revision to the document gratefully acknowledges the firm technical foundation that Brown and Postles established to support the ongoing successfulmore » operation at the DWPF. Their integration of the glass propertycomposition models, developed under the direction of C. M. Jantzen, into a coherent and robust control system, has served the DWPF well over the last 20+ years, even as new challenges, such as the introduction into the DWPF flowsheet of auxiliary streams from the Actinide Removal Process (ARP) and other processes, were met. The purpose of this revision is to provide a technical basis for modifications to PCCS required to support the introduction of waste streams from the Salt Waste Processing Facility (SWPF) into the DWPF flowsheet. An expanded glass composition region is anticipated by the introduction of waste streams from SWPF, and property-composition studies of that glass region have been conducted. Jantzen, once again, directed the development of glass property-composition models applicable for this expanded composition region. The author gratefully acknowledges the technical contributions of C.M. Jantzen leading to the development of these glass property-composition models. The integration of these models into the PCCS constraints necessary to administer future acceptability decisions for the processing at DWPF is provided by this sixth revision of this document.« less

Characterization of Laboratory Prepared Concrete Pastes Exposed to High Alkaline and High Sodium Salt Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langton, C. A.

The objective of this study was to identify potential chemical degradation mechanisms for the Saltstone Disposal Unit (SDU) concretes, which over the performance life of the structures may be exposed to highly alkaline sodium salt solutions containing sulfate, hydroxide, and other potentially corrosive chemicals in salt solution and saltstone flush water, drain water, leachate and / or pore solution. The samples analyzed in this study were cement pastes prepared in the SIMCO Technologies, Inc. concrete laboratory. They were based on the paste fractions of the concretes used to construct the Saltstone Disposal Units (SDUs). SDU 1 and 4 concrete pastesmore » were represented by the PV1 test specimens. The paste in the SDU 2, 3, 5, and 6 concrete was represented by the PV2 test specimens. SIMCO Technologies, Inc. selected the chemicals and proportions in the aggressive solutions to approximate proportions in the saltstone pore solution [2, 3, 5, and 6]. These test specimens were cured for 56 days in curing chamber before being immersed in aggressive solutions. After exposure, the samples were frozen to prevent additional chemical transport and reaction. Selected archived (retrieved from the freezer) samples were sent to the Savannah River National Laboratory (SRNL) for additional characterization using x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray (EDX) spectroscopy. Characterization results are summarized in this report. In addition, a correlation between the oxide composition of the pastes and their chemical durability in the alkaline salt solutions is provided.« less

Characterization of DWPF recycle condensate materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.; Adamson, D. J.; King, W. D.

2015-04-01

A Defense Waste Processing Facility (DWPF) Recycle Condensate Tank (RCT) sample was delivered to the Savannah River National Laboratory (SRNL) for characterization with particular interest in the concentration of I-129, U-233, U-235, total U, and total Pu. Since a portion of Salt Batch 8 will contain DWPF recycle materials, the concentration of I-129 is important to understand for salt batch planning purposes. The chemical and physical characterizations are also needed as input to the interpretation of future work aimed at determining the propensity of the RCT material to foam, and methods to remediate any foaming potential. According to DWPF themore » Tank Farm 2H evaporator has experienced foaming while processing DWPF recycle materials. The characterization work on the RCT samples has been completed and is reported here.« less

DWPF Simulant CPC Studies For SB8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Newell, J. D.

2013-09-25

Prior to processing a Sludge Batch (SB) in the Defense Waste Processing Facility (DWPF), flowsheet studies using simulants are performed. Typically, the flowsheet studies are conducted based on projected composition(s). The results from the flowsheet testing are used to 1) guide decisions during sludge batch preparation, 2) serve as a preliminary evaluation of potential processing issues, and 3) provide a basis to support the Shielded Cells qualification runs performed at the Savannah River National Laboratory (SRNL). SB8 was initially projected to be a combination of the Tank 40 heel (Sludge Batch 7b), Tank 13, Tank 12, and the Tank 51more » heel. In order to accelerate preparation of SB8, the decision was made to delay the oxalate-rich material from Tank 12 to a future sludge batch. SB8 simulant studies without Tank 12 were reported in a separate report.1 The data presented in this report will be useful when processing future sludge batches containing Tank 12. The wash endpoint target for SB8 was set at a significantly higher sodium concentration to allow acceptable glass compositions at the targeted waste loading. Four non-coupled tests were conducted using simulant representing Tank 40 at 110-146% of the Koopman Minimum Acid requirement. Hydrogen was generated during high acid stoichiometry (146% acid) SRAT testing up to 31% of the DWPF hydrogen limit. SME hydrogen generation reached 48% of of the DWPF limit for the high acid run. Two non-coupled tests were conducted using simulant representing Tank 51 at 110-146% of the Koopman Minimum Acid requirement. Hydrogen was generated during high acid stoichiometry SRAT testing up to 16% of the DWPF limit. SME hydrogen generation reached 49% of the DWPF limit for hydrogen in the SME for the high acid run. Simulant processing was successful using previously established antifoam addition strategy. Foaming during formic acid addition was not observed in any of the runs. Nitrite was destroyed in all runs and no N2O was detected during SME processing. Mercury behavior was consistent with that seen in previous SRAT runs. Mercury was stripped below the DWPF limit on 0.8 wt% for all runs. Rheology yield stress fell within or below the design basis of 1-5 Pa. The low acid Tank 40 run (106% acid stoichiometry) had the highest yield stress at 3.78 Pa.« less

Ecological studies related to construction of the Defense Waste Processing Facility on the Savannah River Site. Annual report, FY 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1994-11-01

Construction of the Defense Waste Processing Facility (DWPF) on the Savannah River Site (SRS) began during FY-1984. The Savannah River Ecology Laboratory (SREL) has completed 15 years of ecological studies related to the construction of the DWPF complex. Prior to construction, the 600-acre site (S-Area) contained a Carolina bay and the headwaters of a stream. Through the long-term census taking of biota at the DWPF site and Rainbow Bay, SREL has been evaluating the impact of construction on the biota and the effectiveness of mitigation efforts. similarly, the effects of erosion from the DWPF site on the water quality ofmore » S-Area peripheral streams are being assessed. This research provides supporting data relevant to the National Environmental Policy Act (NEPA) of 1969, the Endangered Species Act of 1973, Executive orders 11988 (Floodplain Management) and 11990 (Protection of Wetlands), and United States Department of Energy (DOE) Guidelines for Compliance with Floodplain/Wetland Environmental Review Requirements (10 CFR 1022).« less

Summary Report For The Analysis Of The Sludge Batch 7b (Macrobatch 9) DWPF Pour Stream Glass Sample For Canister S04023

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, F. C.

2013-11-18

In order to comply with the Defense Waste Processing Facility (DWPF) Waste Form Compliance Plan for Sluldge Batch 7b, Savannah River National Laboratory (SRNL) personnel characterized the Defense Waste Processing Facility (DWPF) pour stream (PS) glass sample collected while filling canister S04023. This report summarizes the results of the compositional analysis for reportable oxides and radionuclides and the normalized Product Consistency Test (PCT) results. The PCT responses indicate that the DWPF produced glass that is significantly more durable than the Environmental Assessment glass.

Testing of the Defense Waste Processing Facility Cold Chemical Dissolution Method in Sludge Batch 9 Qualification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.; Pareizs, J.; Coleman, C.

For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) tests the applicability of the digestion methods used by the DWPF Laboratory for elemental analysis of Sludge Receipt and Adjustment Tank (SRAT) Receipt samples and SRAT Product process control samples. DWPF SRAT samples are typically dissolved using a method referred to as the DWPF Cold Chemical or Cold Chem Method (CC), (see DWPF Procedure SW4- 15.201). Testing indicates that the CC method produced mixed results. The CC method did not result in complete dissolution of either the SRAT Receipt ormore » SRAT Product with some fine, dark solids remaining. However, elemental analyses did not reveal extreme biases for the major elements in the sludge when compared with analyses obtained following dissolution by hot aqua regia (AR) or sodium peroxide fusion (PF) methods. The CC elemental analyses agreed with the AR and PF methods well enough that it should be adequate for routine process control analyses in the DWPF after much more extensive side-by-side tests of the CC method and the PF method are performed on the first 10 SRAT cycles of the Sludge Batch 9 (SB9) campaign. The DWPF Laboratory should continue with their plans for further tests of the CC method during these 10 SRAT cycles.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D; Tommy Edwards, T; Kevin Fox, K

The Savannah River National Laboratory (SRNL) has developed, and continues to enhance, its integrated capability to evaluate the impact of proposed sludge preparation plans on the Defense Waste Processing Facility's (DWPF's) operation. One of the components of this integrated capability focuses on frit development which identifies a viable frit or frits for each sludge option being contemplated for DWPF processing. A frit is considered viable if its composition allows for economic fabrication and if, when it is combined with the sludge option under consideration, the DWPF property/composition models (the models of DWPF's Product Composition Control System (PCCS)) indicate that themore » combination has the potential for an operating window (a waste loading (WL) interval over which the sludge/frit glass system satisfies processability and durability constraints) that would allow DWPF to meet its goals for waste loading and canister production. This report documents the results of SRNL's efforts to identify candidate frit compositions and corresponding predicted operating windows (defined in terms of WL intervals) for the February 2007 compositional projection of Sludge Batch 4 (SB4) developed by the Liquid Waste Organization (LWO). The nominal compositional projection was used to assess projected operating windows (in terms of a waste loading interval over which all predicted properties were classified as acceptable) for various frits, evaluate the applicability of the 0.6 wt% SO{sub 4}{sup =} PCCS limit to the glass systems of interest, and determine the impact (or lack thereof) to the previous SB4 variability studies. It should be mentioned that the information from this report will be coupled with assessments of melt rate to recommend a frit for SB4 processing. The results of this paper study suggest that candidate frits are available to process the nominal SB4 composition over attractive waste loadings of interest to DWPF. Specifically, two primary candidate frits for SB4 processing, Frit 510 and Frit 418, have projected operating windows that should allow for successful processing at DWPF. While Frit 418 has been utilized at DWPF, Frit 510 is a higher B{sub 2}O{sub 3} based frit which could lead to improvements in melt rate. These frits provide relatively large operating windows and demonstrate robustness to possible sludge compositional variation while avoiding potential nepheline formation issues. In addition, assessments of SO{sub 4}{sup =} solubility indicate that the 0.6 wt% SO{sub 4}{sup =} limit in PCCS is applicable for the Frit 418 and the Frit 510 based SB4 glass systems.« less

Reactive amendment saltstone (RAS). A novel approach for improved sorption/retention of radionuclides such as technetium and iodine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dixon, K. L.; Knox, A. S.; Cozzi, A. D.

This study examined the use of reactive amendments (hydroxyapatite, activated carbon, and two types of organoclays) that prior research suggests may improve retention of 99Tc and 129I. Tests were conducted using surrogates for 99Tc (NaReO 4) and 129I (NaI). Results showed that adding up to 10% of organoclay improved the retention of Re without adversely impacting hydraulic properties. To a lesser extent, iodine retention was also improved by adding up to 10% organoclay. Numerical modeling showed that using organoclay as a reactive barrier may significantly retard 99Tc release from saltstone disposal units.

VERIFICATION OF THE DEFENSE WASTE PROCESSING FACILITY PROCESS DIGESTION METHOD FOR THE SLUDGE BATCH 6 QUALIFICATION SAMPLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Click, D.; Jones, M.; Edwards, T.

2010-06-09

For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) confirms applicability of the digestion method to be used by the DWPF lab for elemental analysis of Sludge Receipt and Adjustment Tank (SRAT) receipt samples and SRAT product process control samples.1 DWPF SRAT samples are typically dissolved using a room temperature HF-HNO3 acid dissolution (i.e., DWPF Cold Chem (CC) Method, see DWPF Procedure SW4-15.201) and then analyzed by inductively coupled plasma - atomic emission spectroscopy (ICPAES). In addition to the CC method confirmation, the DWPF lab's mercury (Hg) digestion methodmore » was also evaluated for applicability to SB6 (see DWPF procedure 'Mercury System Operating Manual', Manual: SW4-15.204. Section 6.1, Revision 5, Effective date: 12-04-03). This report contains the results and comparison of data generated from performing the Aqua Regia (AR), Sodium Peroxide/Hydroxide Fusion (PF) and DWPF Cold Chem (CC) method digestion of Sludge Batch 6 (SB6) SRAT Receipt and SB6 SRAT Product samples. For validation of the DWPF lab's Hg method, only SRAT receipt material was used and compared to AR digestion results. The SB6 SRAT Receipt and SB6 SRAT Product samples were prepared in the SRNL Shielded Cells, and the SRAT Receipt material is representative of the sludge that constitutes the SB6 Batch or qualification composition. This is the sludge in Tank 51 that is to be transferred into Tank 40, which will contain the heel of Sludge Batch 5 (SB5), to form the SB6 Blend composition. In addition to the 16 elements currently measured by the DWPF, this report includes Hg and thorium (Th) data (Th comprising {approx}2.5 - 3 Wt% of the total solids in SRAT Receipt and SRAT Product, respectively) and provides specific details of ICP-AES analysis of Th. Thorium was found to interfere with the U 367.007 nm emission line, and an inter-element correction (IEC) had to be applied to U data, which is also discussed. The results for any one particular element should not be used in any way to identify the form or speciation of a particular element without support from XRD analysis or used to estimate ratios of compounds in the sludge.« less

SUMMARY OF FY11 SULFATE RETENTION STUDIES FOR DEFENSE WASTE PROCESSING FACILITY GLASS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, K.; Edwards, T.

2012-05-08

This report describes the results of studies related to the incorporation of sulfate in high level waste (HLW) borosilicate glass produced at the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF). A group of simulated HLW glasses produced for earlier sulfate retention studies was selected for full chemical composition measurements to determine whether there is any clear link between composition and sulfate retention over the compositional region evaluated. In addition, the viscosity of several glasses was measured to support future efforts in modeling sulfate solubility as a function of predicted viscosity. The intent of these studies was to developmore » a better understanding of sulfate retention in borosilicate HLW glass to allow for higher loadings of sulfate containing waste. Based on the results of these and other studies, the ability to improve sulfate solubility in DWPF borosilicate glasses lies in reducing the connectivity of the glass network structure. This can be achieved, as an example, by increasing the concentration of alkali species in the glass. However, this must be balanced with other effects of reduced network connectivity, such as reduced viscosity, potentially lower chemical durability, and in the case of higher sodium and aluminum concentrations, the propensity for nepheline crystallization. Future DWPF processing is likely to target higher waste loadings and higher sludge sodium concentrations, meaning that alkali concentrations in the glass will already be relatively high. It is therefore unlikely that there will be the ability to target significantly higher total alkali concentrations in the glass solely to support increased sulfate solubility without the increased alkali concentration causing failure of other Product Composition Control System (PCCS) constraints, such as low viscosity and durability. No individual components were found to provide a significant improvement in sulfate retention (i.e., an increase of the magnitude necessary to have a dramatic impact on blending, washing, or waste loading strategies for DWPF) for the glasses studied here. In general, the concentrations of those species that significantly improve sulfate solubility in a borosilicate glass must be added in relatively large concentrations (e.g., 13 to 38 wt % or more of the frit) in order to have a substantial impact. For DWPF, these concentrations would constitute too large of a portion of the frit to be practical. Therefore, it is unlikely that specific additives may be introduced into the DWPF glass via the frit to significantly improve sulfate solubility. The results presented here continue to show that sulfate solubility or retention is a function of individual glass compositions, rather than a property of a broad glass composition region. It would therefore be inappropriate to set a single sulfate concentration limit for a range of DWPF glass compositions. Sulfate concentration limits should continue to be identified and implemented for each sludge batch. The current PCCS limit is 0.4 wt % SO{sub 4}{sup 2-} in glass, although frit development efforts have led to an increased limit of 0.6 wt % for recent sludge batches. Slightly higher limits (perhaps 0.7-0.8 wt %) may be possible for future sludge batches. An opportunity for allowing a higher sulfate concentration limit at DWPF may lay lie in improving the laboratory experiments used to set this limit. That is, there are several differences between the crucible-scale testing currently used to define a limit for DWPF operation and the actual conditions within the DWPF melter. In particular, no allowance is currently made for sulfur partitioning (volatility versus retention) during melter processing as the sulfate limit is set for a specific sludge batch. A better understanding of the partitioning of sulfur in a bubbled melter operating with a cold cap as well as the impacts of sulfur on the off-gas system may allow a higher sulfate concentration limit to be established for the melter feed. This approach would have to be taken carefully to ensure that a sulfur salt layer is not formed on top of the melt pool while allowing higher sulfur based feeds to be processed through DWPF.« less

Crystallization In High Level Waste (HLW) Glass Melters: Operational Experience From The Savannah River Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, K. M.

2014-02-27

processing strategy for the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The basis of this alternative approach is an empirical model predicting the crystal accumulation in the WTP glass discharge riser and melter bottom as a function of glass composition, time, and temperature. When coupled with an associated operating limit (e.g., the maximum tolerable thickness of an accumulated layer of crystals), this model could then be integrated into the process control algorithms to formulate crystal tolerant high level waste (HLW) glasses targeting higher waste loadings while still meeting process related limits and melter lifetime expectancies. This report provides amore » review of the scaled melter testing that was completed in support of the Defense Waste Processing Facility (DWPF) melter. Testing with scaled melters provided the data to define the DWPF operating limits to avoid bulk (volume) crystallization in the un-agitated DWPF melter and provided the data to distinguish between spinels generated by K-3 refractory corrosion versus spinels that precipitated from the HLW glass melt pool. This report includes a review of the crystallization observed with the scaled melters and the full scale DWPF melters (DWPF Melter 1 and DWPF Melter 2). Examples of actual DWPF melter attainment with Melter 2 are given. The intent is to provide an overview of lessons learned, including some example data, that can be used to advance the development and implementation of an empirical model and operating limit for crystal accumulation for WTP. Operation of the first and second (current) DWPF melters has demonstrated that the strategy of using a liquidus temperature predictive model combined with a 100 °C offset from the normal melter operating temperature of 1150 °C (i.e., the predicted liquidus temperature (TL) of the glass must be 1050 °C or less) has been successful in preventing any detrimental accumulation of spinel in the DWPF melt pool, and spinel has not been observed in any of the pour stream glass samples. Spinel was observed at the bottom of DWPF Melter 1 as a result of K-3 refractory corrosion. Issues have occurred with accumulation of spinel in the pour spout during periods of operation at higher waste loadings. Given that both DWPF melters were or have been in operation for greater than 8 years, the service life of the melters has far exceeded design expectations. It is possible that the DWPF liquidus temperature approach is conservative, in that it may be possible to successfully operate the melter with a small degree of allowable crystallization in the glass. This could be a viable approach to increasing waste loading in the glass assuming that the crystals are suspended in the melt and swept out through the riser and pour spout. Additional study is needed, and development work for WTP might be leveraged to support a different operating limit for the DWPF. Several recommendations are made regarding considerations that need to be included as part of the WTP crystal tolerant strategy based on the DWPF development work and operational data reviewed here. These include: Identify and consider the impacts of potential heat sinks in the WTP melter and glass pouring system; Consider the contributions of refractory corrosion products, which may serve to nucleate additional crystals leading to further accumulation; Consider volatilization of components from the melt (e.g., boron, alkali, halides, etc.) and determine their impacts on glass crystallization behavior; Evaluate the impacts of glass REDuction/OXidation (REDOX) conditions and the distribution of temperature within the WTP melt pool and melter pour chamber on crystal accumulation rate; Consider the impact of precipitated crystals on glass viscosity; Consider the impact of an accumulated crystalline layer on thermal convection currents and bubbler effectiveness within the melt pool; Evaluate the impact of spinel accumulation on Joule heating of the WTP melt pool; and Include noble metals in glass melt experiments because of their potential to act as nucleation sites for spinel crystallization.« less

Assessment of the impact of TOA partitioning on DWPF off-gas flammability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, W. E.

2013-06-01

An assessment has been made to evaluate the impact on the DWPF melter off-gas flammability of increasing the amount of TOA in the current solvent used in the Modular Caustic-Side Solvent Extraction Process Unit (MCU) process. The results of this study showed that the concentrations of nonvolatile carbon of the current solvent limit (150 ppm) in the Slurry Mix Evaporator (SME) product would be about 7% higher and the nonvolatile hydrogen would be 2% higher than the actual current solvent (126 ppm) with an addition of up to 3 ppm of TOA when the concentration of Isopar L in themore » effluent transfer is controlled below 87 ppm and the volume of MCU effluent transfer to DWPF is limited to 15,000 gallons per Sludge Receipt and Adjustment Tank (SRAT)/SME cycle. Therefore, the DWPF melter off-gas flammability assessment is conservative for up to an additional 3 ppm of TOA in the effluent based on these assumptions. This report documents the calculations performed to reach this conclusion.« less

Composite analysis E-area vaults and saltstone disposal facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, J.R.

1997-09-01

This report documents the Composite Analysis (CA) performed on the two active Savannah River Site (SRS) low-level radioactive waste (LLW) disposal facilities. The facilities are the Z-Area Saltstone Disposal Facility and the E-Area Vaults (EAV) Disposal Facility. The analysis calculated potential releases to the environment from all sources of residual radioactive material expected to remain in the General Separations Area (GSA). The GSA is the central part of SRS and contains all of the waste disposal facilities, chemical separations facilities and associated high-level waste storage facilities as well as numerous other sources of radioactive material. The analysis considered 114 potentialmore » sources of radioactive material containing 115 radionuclides. The results of the CA clearly indicate that continued disposal of low-level waste in the saltstone and EAV facilities, consistent with their respective radiological performance assessments, will have no adverse impact on future members of the public.« less

Nuclear Waste: Defense Waste Processing Facility-Cost, Schedule, and Technical Issues.

DTIC Science & Technology

1992-06-17

gallons of high-level radioactive waste stored in underground tanks at the savannah major facility involved Is the Defense Waste Processing Facility ( DwPF ...As a result of concerns about potential problems with the DWPF and delays in its scheduled start-up, the Chairman of the Environment, Energy, and...Natural Resources Subcommittee, House Committee on Government Operations, asked GAO to review the status of the DWPF and other facilities. This report

Comparative risk assessments for the production and interim storage of glass and ceramic waste forms: Defense waste processing facility

NASA Astrophysics Data System (ADS)

Huang, J. C.; Wright, W. V.

1982-04-01

The Defense Waste Processing Facility (DWPF) for immobilizing nuclear high level waste (HLW) is scheduled to be built. High level waste is produced when reactor components are subjected to chemical separation operations. Two candidates for immobilizing this HLW are borosilicate glass and crystalline ceramic, either being contained in weld sealed stainless steel canisters. A number of technical analyses are being conducted to support a selection between these two waste forms. The risks associated with the manufacture and interim storage of these two forms in the DWPF are compared. Process information used in the risk analysis was taken primarily from a DWPF processibility analysis. The DWPF environmental analysis provided much of the necessary environmental information.

Infrasound Detection of Rocket Launches

DTIC Science & Technology

2000-09-01

infrasound pressure, and λ and µ are the Lame and shear modulii. Seismic data was available from the IRIS data center for the seismic station DWPF ...the bandwidth of interest. Figure 4 shows a recording of STS-93 (07/24/99 04:31:00GMT) at DWPF (97 km). The largest seismic amplitudes are consistent...lasts ~400 seconds. The dominant frequency (~4 Hz) at DWPF is consistent with the long-range infrasound signals observed at DLIAR. Figure 3. Seismic

Results for the DWPF Slurry Mix Evaporator Condensate Tank, Off Gas Condensate Tank, And Recycle Collection Tank Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

TERRI, FELLINGER

2004-12-21

The Defense Waste Processing Facility, DWPF, currently generates approximately 1.4 million gallons of recycle water per year during Sludge-Only operations. DWPF has minimized condensate generation to 1.4 million gallons by not operating the Steam Atomized Scrubbers, SASs, for the melter off gas system. By not operating the SASs, DWPF has reduced the total volume by approximately 800,000 gallons of condensate per year. Currently, the recycle stream is sent to back to the Tank Farm and processed through the 2H Evaporator system. To alleviate the load on the 2H Evaporator system, an acid evaporator design is being considered as an alternatemore » processing and/or concentration method for the DWPF recycle stream. In order to support this alternate processing option, the DWPF has requested that the chemical and radionuclide compositions of the Off Gas Condensate Tank, OGCT, Slurry Mix Evaporator Condensate Tank, SMECT, Recycle Collection Tank, RCT, and the Decontamination Waste Treatment Tank, DWTT, be determined as a part of the process development work for the acid evaporator design. Samples have been retrieved from the OGCT, RCT, and SMECT and have been sent to the Savannah River National Laboratory, SRNL for this characterization. The DWTT samples have been recently shipped to SRNL. The results for the DWTT samples will be issued at later date.« less

Characterization of DWPF recycle condensate tank materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.

2015-01-01

A Defense Waste Processing Facility (DWPF) Recycle Condensate Tank (RCT) sample was delivered to the Savannah River National Laboratory (SRNL) for characterization with particular interest in the concentration of I-129, U-233, U-235, total U, and total Pu. Since a portion of Salt Batch 8 will contain DWPF recycle materials, the concentration of I-129 is important to undertand for salt batch planning purposes. The chemical and physical characterizations are also needed as input to the interpretation of future work aimed at determining the propensity of the RCT material to foam, and methods to remediate any foaming potential. According to DWPF themore » Tank Farm 2H evaporator has experienced foaming while processing DWPF recycle materials. The characterization work on the RCT samples has been completed and is reported here. The composition of the Sludge Batch 8 (SB8) RCT material is largely a low base solution of 0.2M NaNO 2 and 0.1M NaNO 3 with a small amount of formate present. Insoluble solids comprise only 0.05 wt.% of the slurry. The solids appear to be largely sludge-like solids based on elemental composition and SEM-EDS analysis. The sample contains an elevated concentration of I-129 (38x) and substantial 59% fraction of Tc-99, as compared to the incoming SB8 Tank 40 feed material. The Hg concentration is 5x, when compared to Fe, of that expected based on sludge carryover. The total U and Pu concentrations are reduced significantly, 0.536 wt.% TS and 2.42E-03 wt.% TS, respectively, with the fissile components, U-233, U-235, Pu-239, and Pu-241, an order of magnitude lower in concentration than those in the SB8 Tank 40 DWPF feed material. This report will be revised to include the foaming study requested in the TTR and outlined in the TTQAP when that work is concluded.« less

Actual waste demonstration of the nitric-glycolic flowsheet for sludge batch 9 qualification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Newell, D.; Pareizs, J.; Martino, C.

For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) performs qualification testing to demonstrate that the sludge batch is processable. Based on the results of this actual-waste qualification and previous simulant studies, SRNL recommends implementation of the nitric-glycolic acid flowsheet in DWPF. Other recommendations resulting from this demonstration are reported in section 5.0.

Literature review: Assessment of DWPF melter and melter off-gas system lifetime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reigel, M. M.

2015-07-30

A glass melter for use in processing radioactive waste is a challenging environment for the materials of construction (MOC) resulting from a combination of high temperatures, chemical attack, and erosion/corrosion; therefore, highly engineered materials must be selected for this application. The focus of this report is to review the testing and evaluations used in the selection of the Defense Waste Processing Facility (DWPF), glass contact MOC specifically the Monofrax ® K-3 refractory and Inconel ® 690 alloy. The degradation or corrosion mechanisms of these materials during pilot scale testing and in-service operation were analyzed over a range of oxidizing andmore » reducing flowsheets; however, DWPF has primarily processed a reducing flowsheet (i.e., Fe 2+/ΣFe of 0.09 to 0.33) since the start of radioactive operations. This report also discusses the materials selection for the DWPF off-gas system and the corrosion evaluation of these materials during pilot scale testing and non-radioactive operations of DWPF Melter #1. Inspection of the off-gas components has not been performed during radioactive operations with the exception of maintenance because of plugging.« less

Literature review: Assessment of DWPF melter and melter off-gas system lifetime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reigel, M.

2015-07-30

A glass melter for use in processing radioactive waste is a challenging environment for the materials of construction (MOC) resulting from a combination of high temperatures, chemical attack, and erosion/corrosion; therefore, highly engineered materials must be selected for this application. The focus of this report is to review the testing and evaluations used in the selection of the Defense Waste Processing Facility (DWPF), glass contact MOC specifically the Monofrax® K-3 refractory and Inconel® 690 alloy. The degradation or corrosion mechanisms of these materials during pilot scale testing and in-service operation were analyzed over a range of oxidizing and reducing flowsheets;more » however, DWPF has primarily processed a reducing flowsheet (i.e., Fe 2+/ΣFe of 0.09 to 0.33) since the start of radioactive operations. This report also discusses the materials selection for the DWPF off-gas system and the corrosion evaluation of these materials during pilot scale testing and non-radioactive operations of DWPF Melter #1. Inspection of the off-gas components has not been performed during radioactive operations with the exception of maintenance because of plugging.« less

Sludge Washing and Demonstration of the DWPF Nitric/Formic Flowsheet in the SRNL Shielded Cells for Sludge Batch 9 Qualification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J.; Newell, D.; Martino, C.

Savannah River National Laboratory (SRNL) was requested by Savannah River Remediation (SRR) to qualify the next batch of sludge – Sludge Batch 9 (SB9). Current practice is to prepare sludge batches in Tank 51 by transferring sludge to Tank 51 from other tanks. The sludge is washed and transferred to Tank 40, the current Defense Waste Process Facility (DWPF) feed tank. Prior to sludge transfer from Tank 51 to Tank 40, the Tank 51 sludge must be qualified. SRNL qualifies the sludge in multiple steps. First, a Tank 51 sample is received, then characterized, washed, and again characterized. SRNL thenmore » demonstrates the DWPF Chemical Process Cell (CPC) flowsheet with the sludge. The final step of qualification involves chemical durability measurements of glass fabricated in the DWPF CPC demonstrations. In past sludge batches, SRNL had completed the DWPF demonstration with Tank 51 sludge. For SB9, SRNL has been requested to process a blend of Tank 51 and Tank 40 at a targeted ratio of 44% Tank 51 and 56% Tank 40 on an insoluble solids basis.« less

Evaluation of materials and surface treatments for the DWPF melter pour spout bellows protective liner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Imrich, K.J.; Bickford, D.F.; Wicks, G.G.

1997-06-27

A study was undertaken to evaluate a variety of materials and coatings for the DWPF pour spout bellows liner. The intent was to identify materials that would minimize or eliminate adherence of glass on the bellows liner wall and help minimize possible pluggage during glass pouring operations in DWPF. Glass has been observed adhering to the current bellow`s liner, which is made of 304L stainless steel. Materials were identified which successfully allowed molten glass to hit these surfaces and not adhere. Results of this study suggest that if these materials are used in the pouring system glass could still fallmore » into the canister without appreciable plugging, even if an unstable glass stream is produced. The materials should next be evaluated under the most realistic DWPF conditions possible. Other findings of this study include the following: (1) increasing coupon thickness produced a favorable increase in the glass sticking temperature; (2) highly polished surfaces, with the exception of the oxygen-free copper coupon coated with Armoloy dense chromium, did not produce a significant improvement in the glass sticking temperature, increasing angle of contact of the coupon to the falling glass did not yield a significant performance improvement; (3) electroplating with gold and silver and various diffusion coatings did not produce a significant increase in the glass sticking temperature. However, they may provide added oxidation and corrosion resistance for copper and bronze liners. Boron nitride coatings delaminated immediately after contact with the molten glass.« less

DWPF STARTUP FRIT VISCOSITY MEASUREMENT ROUND ROBIN RESULTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crum, Jarrod V.; Edwards, Tommy B.; Russell, Renee L.

2012-07-31

A viscosity standard is needed to replace the National Institute of Standards and Technology (NIST) glasses currently being used to calibrate viscosity measurement equipment. The current NIST glasses are either unavailable or less than ideal for calibrating equipment to measure the viscosity of high-level waste glasses. This report documents the results of a viscosity round robin study conducted on the Defense Waste Processing Facility (DWPF) startup frit. DWPF startup frit was selected because its viscosity-temperature relationship is similar to most DWPF and Hanford high-level waste glass compositions. The glass underwent grinding and blending to homogenize the large (100 lb) batch.more » Portions of the batch were supplied to the laboratories (named A through H) for viscosity measurements following a specified temperature schedule with a temperature range of 1150 C to 950 C and with an option to measure viscosity at lower temperatures if their equipment was capable of measuring at the higher viscosities. Results were used to fit the Vogel-Tamman-Fulcher and Arrhenius equations to viscosity as a function of temperature for the entire temperature range of 460 C through 1250 C as well as the limited temperature interval of approximately 950 C through 1250 C. The standard errors for confidence and prediction were determined for the fitted models.« less

IMPROVED ANTIFOAM AGENT STUDY END OF YEAR REPORT, EM PROJECT 3.2.3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D.; Koopman, D.; Newell, J.

2011-09-30

Antifoam 747 is added to minimize foam produced by process gases and water vapor during chemical processing of sludge in the Defense Waste Processing Facility (DWPF). This allows DWPF to maximize acid addition and evaporation rates to minimize the cycle time in the Chemical Processing Cell (CPC). Improvements in DWPF melt rate due to the addition of bubblers in the melter have resulted in the need for further reductions in cycle time in the CPC. This can only be accomplished with an effective antifoam agent. DWPF production was suspended on March 22, 2011 as the result of a Flammable Gasmore » New Information/(NI) Potential Inadequacy in the Safety Analysis (PISA). The issue was that the DWPF melter offgas flammability strategy did not take into account the H and C in the antifoam, potentially flammable components, in the melter feed. It was also determined the DWPF was using much more antifoam than anticipated due to a combination of longer processing in the CPC due to high Hg, longer processing due to Actinide Removal Process (ARP)/Modular Caustic Side Solvent Extraction Unit (MCU) additions, and adding more antifoam than recommended. The resolution to the PISA involved and assessment of the impact of the antifoam on melter flammability and the implementation of a strategy to control additions within acceptable levels. This led to the need to minimize the use of Antifoam 747 in processing beginning in May 2011. DWPF has had limited success in using Antifoam 747 in caustic processing. Since starting up the ARP facility, the ARP product (similar chemically to caustic sludge) is added to the Sludge Receipt and Adjustment Tank (SRAT) at boiling and evaporated to maintain a constant SRAT volume. Although there is very little offgas generated during caustic boiling, there is a large volume of water vapor produced which can lead to foaming. High additions and more frequent use of antifoam are used to mitigate the foaming during caustic boiling. The result of these three issues above is that DWPF had three antifoam needs in FY2011: (1) Determine the cause of the poor Antifoam 747 performance during caustic boiling; (2) Determine the decomposition products of Antifoam 747 during CPC processing; and (3) Improve the effectiveness of Antifoam 747, in order to minimize the amount used. Testing was completed by Illinois Institute of Technology (IIT) and Savannah River National Laboratory (SRNL) researchers to address these questions. The testing results reported were funded by both DWPF and DOE/EM 31. Both sets of results are reported in this document for completeness. The results of this research are summarized: (1) The cause for the poor Antifoam 747 performance during caustic boiling was the high hydrolysis rate, cleaving the antifoam molecule in two, leading to poor antifoam performance. In testing with pH solutions from 1 to 13, the antifoam degraded quickly at a pH < 4 and pH > 10. As the antifoam decomposed it lost its spreading ability (wetting agent performance), which is crucial to its antifoaming performance. During testing of a caustic sludge simulants, there was more foam in tests with added Antifoam 747 than in tests without added antifoam. (2) Analyses were completed to determine the composition of the two antifoam components and Antifoam 747. In addition, the decomposition products of Antifoam 747 were determined during CPC processing of sludge simulants. The main decomposition products were identified primarily as Long Chain Siloxanes, boiling point > 400 C. Total antifoam recovery was 33% by mass. In a subsequent study, various compounds potentially related to antifoam were found using semi-volatile organic analysis and volatile organic analysis on the hexane extractions and hexane rinses. These included siloxanes, trimethyl silanol, methoxy trimethyl silane, hexamethyl disiloxane, aliphatic hydrocarbons, dioctyl phthalate, and emulsifiers. Cumulatively, these species amounted to less than 3% of the antifoam mass. The majority of the antifoam was identified using carbon analysis of the SRAT product (40-80% by mass) and silicon analysis (23-83% by mass) of the condensate. Both studies recommended a better solvent for antifoam and more specific tests for antifoam degradation products than the Si and C analyses used. (3) The DWPF Antifoam 747 Purchase Specification was revised in Month, 2011 with a goal of increasing the quality of Antifoam 747. The purchase specification was changed to specify the manufacturer and product for both components that are blended by Siovation to produce Antifoam 747 for DWPF. Testing of Antifoam produced using both the old and new antifoam specifications perform very similarly in testing. Since the change in purchase specification has not improved antifoam performance, an improved antifoam agent is required.« less

Material compatibility evaluation for DWPF nitric-glycolic acid-literature review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J.; Skidmore, E.

2013-06-01

Glycolic acid is being evaluated as an alternative for formic and nitric acid in the DWPF flowsheet. Demonstration testing and modeling for this new flowsheet has shown that glycolic acid and glycolate has a potential to remain in certain streams generated during the production of the nuclear waste glass. A literature review was conducted to assess the impact of glycolic acid on the corrosion of the materials of construction for the DWPF facility as well as facilities downstream which may have residual glycolic acid and glycolates present. The literature data was limited to solutions containing principally glycolic acid.

DWPF RECYCLE EVAPORATOR FLOWSHEET EVALUATION (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M

2005-04-30

The Defense Waste Processing Facility (DWPF) converts the high level waste slurries stored at the Savannah River Site into borosilicate glass for long-term storage. The vitrification process results in the generation of approximately five gallons of dilute recycle streams for each gallon of waste slurry vitrified. This dilute recycle stream is currently transferred to the H-area Tank Farm and amounts to approximately 1,400,000 gallons of effluent per year. Process changes to incorporate salt waste could increase the amount of effluent to approximately 2,900,000 gallons per year. The recycle consists of two major streams and four smaller streams. The first majormore » recycle stream is condensate from the Chemical Process Cell (CPC), and is collected in the Slurry Mix Evaporator Condensate Tank (SMECT). The second major recycle stream is the melter offgas which is collected in the Off Gas Condensate Tank (OGCT). The four smaller streams are the sample flushes, sump flushes, decon solution, and High Efficiency Mist Eliminator (HEME) dissolution solution. These streams are collected in the Decontamination Waste Treatment Tank (DWTT) or the Recycle Collection Tank (RCT). All recycle streams are currently combined in the RCT and treated with sodium nitrite and sodium hydroxide prior to transfer to the tank farm. Tank Farm space limitations and previous outages in the 2H Evaporator system due to deposition of sodium alumino-silicates have led to evaluation of alternative methods of dealing with the DWPF recycle. One option identified for processing the recycle was a dedicated evaporator to concentrate the recycle stream to allow the solids to be recycled to the DWPF Sludge Receipt and Adjustment Tank (SRAT) and the condensate from this evaporation process to be sent and treated in the Effluent Treatment Plant (ETP). In order to meet process objectives, the recycle stream must be concentrated to 1/30th of the feed volume during the evaporation process. The concentrated stream must be pumpable to the DWPF SRAT vessel and should not precipitate solids to avoid fouling the evaporator vessel and heat transfer coils. The evaporation process must not generate excessive foam and must have a high Decontamination Factor (DF) for many species in the evaporator feed to allow the condensate to be transferred to the ETP. An initial scoping study was completed in 2001 to evaluate the feasibility of the evaporator which concluded that the concentration objectives could be met. This initial study was based on initial estimates of recycle concentration and was based solely on OLI modeling of the evaporation process. The Savannah River National Laboratory (SRNL) has completed additional studies using simulated recycle streams and OLI{reg_sign} simulations. Based on this work, the proposed flowsheet for the recycle evaporator was evaluated for feasibility, evaporator design considerations, and impact on the DWPF process. This work was in accordance with guidance from DWPF-E and was performed in accordance with the Technical Task and Quality Assurance Plan.« less

Preliminary analysis of species partitioning in the DWPF melter. Sludge batch 7A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, A. S.; Smith III, F. G.; McCabe, D. J.

2017-01-01

The work described in this report is preliminary in nature since its goal was to demonstrate the feasibility of estimating the off-gas carryover from the Defense Waste Processing Facility (DWPF) melter based on a simple mass balance using measured feed and glass pour stream (PS) compositions and time-averaged melter operating data over the duration of one canister-filling cycle. The DWPF has been in radioactive operation for over 20 years processing a wide range of high-level waste (HLW) feed compositions under varying conditions such as bubbled vs. non-bubbled and feeding vs. idling. So it is desirable to find out how themore » varying feed compositions and operating parameters would have impacted the off-gas entrainment. However, the DWPF melter is not equipped with off-gas sampling or monitoring capabilities, so it is not feasible to measure off-gas entrainment rates directly. The proposed method provides an indirect way of doing so.« less

Defense Waste Processing Facility (DWPF) Viscosity Model: Revisions for Processing High TiO 2 Containing Glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C. M.; Edwards, T. B.

Radioactive high-level waste (HLW) at the Savannah River Site (SRS) has successfully been vitrified into borosilicate glass in the Defense Waste Processing Facility (DWPF) since 1996. Vitrification requires stringent product/process (P/P) constraints since the glass cannot be reworked once it is poured into ten foot tall by two foot diameter canisters. A unique “feed forward” statistical process control (SPC) was developed for this control rather than statistical quality control (SQC). In SPC, the feed composition to the DWPF melter is controlled prior to vitrification. In SQC, the glass product would be sampled after it is vitrified. Individual glass property-composition modelsmore » form the basis for the “feed forward” SPC. The models transform constraints on the melt and glass properties into constraints on the feed composition going to the melter in order to guarantee, at the 95% confidence level, that the feed will be processable and that the durability of the resulting waste form will be acceptable to a geologic repository. The DWPF SPC system is known as the Product Composition Control System (PCCS). The DWPF will soon be receiving wastes from the Salt Waste Processing Facility (SWPF) containing increased concentrations of TiO 2, Na 2O, and Cs 2O . The SWPF is being built to pretreat the high-curie fraction of the salt waste to be removed from the HLW tanks in the F- and H-Area Tank Farms at the SRS. In order to process TiO 2 concentrations >2.0 wt% in the DWPF, new viscosity data were developed over the range of 1.90 to 6.09 wt% TiO 2 and evaluated against the 2005 viscosity model. An alternate viscosity model is also derived for potential future use, should the DWPF ever need to process other titanate-containing ion exchange materials. The ultimate limit on the amount of TiO 2 that can be accommodated from SWPF will be determined by the three PCCS models, the waste composition of a given sludge batch, the waste loading of the sludge batch, and the frit used for vitrification.« less

DWPF SIMULANT CPC STUDIES FOR SB7B

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopman, D.

2011-11-01

Lab-scale DWPF simulations of Sludge Batch 7b (SB7b) processing were performed. Testing was performed at the Savannah River National Laboratory - Aiken County Technology Laboratory (SRNL-ACTL). The primary goal of the simulations was to define a likely operating window for acid stoichiometry for the DWPF Sludge Receipt and Adjustment Tank (SRAT). In addition, the testing established conditions for the SRNL Shielded Cells qualification simulation of SB7b-Tank 40 blend, supported validation of the current glass redox model, and validated the coupled process flowsheet at the nominal acid stoichiometry. An acid window of 105-140% by the Koopman minimum acid (KMA) equation (107-142%more » DWPF Hsu equation) worked for the sludge-only flowsheet. Nitrite was present in the SRAT product for the 105% KMA run at 366 mg/kg, while SME cycle hydrogen reached 94% of the DWPF Slurry Mix Evaporator (SME) cycle limit in the 140% KMA run. The window was determined for sludge with added caustic (0.28M additional base, or roughly 12,000 gallons 50% NaOH to 820,000 gallons waste slurry). A suitable processing window appears to be 107-130% DWPF acid equation for sludge-only processing allowing some conservatism for the mapping of lab-scale simulant data to full-scale real waste processing including potentially non-conservative noble metal and mercury concentrations. This window should be usable with or without the addition of up to 7,000 gallons of caustic to the batch. The window could potentially be wider if caustic is not added to SB7b. It is recommended that DWPF begin processing SB7b at 115% stoichiometry using the current DWPF equation. The factor could be increased if necessary, but changes should be made with caution and in small increments. DWPF should not concentrate past 48 wt.% total solids in the SME cycle if moderate hydrogen generation is occurring simultaneously. The coupled flowsheet simulation made more hydrogen in the SRAT and SME cycles than the sludge-only run with the same acid stoichiometric factor. The slow acid addition in MCU seemed to alter the reactions that consumed the small excess acid present such that hydrogen generation was promoted relative to sludge-only processing. The coupled test reached higher wt.% total solids, and this likely contributed to the SME cycle hydrogen limit being exceeded at 110% KMA. It is clear from the trends in the SME processing GC data, however, that the frit slurry formic acid contributed to driving the hydrogen generation rate above the SME cycle limit. Hydrogen generation rates after the second frit addition generally exceeded those after the first frit addition. SRAT formate loss increased with increasing acid stoichiometry (15% to 35%). A substantial nitrate gain which was observed to have occurred after acid addition (and nitrite destruction) was reversed to a net nitrate loss in runs with higher acid stoichiometry (nitrate in SRAT product less than sum of sludge nitrate and added nitric acid). Increased ammonium ion formation was also indicated in the runs with nitrate loss. Oxalate loss on the order 20% was indicated in three of the four acid stoichiometry runs and in the coupled flowsheet run. The minimum acid stoichiometry run had no indicated loss. The losses were of the same order as the official analytical uncertainty of the oxalate concentration measurement, but were not randomly distributed about zero loss, so some actual loss was likely occurring. Based on the entire set of SB7b test data, it is recommended that DWPF avoid concentrating additional sludge solids in single SRAT batches to limit the concentrations of noble metals to SB7a processing levels (on a grams noble metal per SRAT batch basis). It is also recommended that DWPF drop the formic acid addition that accompanies the process frit 418 additions, since SME cycle data showed considerable catalytic activity for hydrogen generation from this additional acid (about 5% increase in stoichiometry occurred from the frit formic acid). Frit 418 also does not appear to need formic acid addition to prevent gel formation in the frit slurry. Simulant processing was successful using 100 ppm of 747 antifoam added prior to nitric acid instead of 200 ppm. This is a potential area for DWPF to cut antifoam usage in any future test program. An additional 100 ppm was added before formic acid addition. Foaming during formic acid addition was not observed. No build-up of oily or waxy material was observed in the off-gas equipment. Lab-scale mercury stripping behavior was similar to SB6 and SB7a. More mercury was unaccounted for as the acid stoichiometry increased.« less

Characterization of Radioactive Waste Melter Feed Vitrified By Microwave Energy,

DTIC Science & Technology

processed in the Defense Waste Processing Facility ( DWPF ) and poured into stainless steel canisters for eventual disposal in a geologic repository...Vitrification of melter feed samples is necessary for DWPF process and product control. Microwave fusion of melter feed at approximately 12OO deg C for 10

Urban Fire Simulation. Version 2

DTIC Science & Technology

1993-02-01

of the building. In this case the distribution of windows in the tract per floor ( DWPF (FLOORHT)) is calculated under the assumption that the number of...given urban area. The probability that no room on the subject floor will flash over is calculated at label (V) from PNRFOF DWPF (FLOORHT) (1 - FFORF

Results for the first quarter calendar year 2017 tank 50H salt solution sample

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, C. L.

2017-04-12

In this memorandum, the chemical and radionuclide contaminant results from the First Quarter Calendar Year 2017 (CY17) sample of Tank 50H salt solution are presented in tabulated form. The First Quarter CY17 Tank 50H samples [a 200 mL sample obtained 6” below the surface (HTF-50-17-7) and a 1 L sample obtained 66” from the tank bottom (HTF-50-17-8)] were obtained on January 15, 2017 and received at Savannah River National Laboratory (SRNL) on January 16, 2017. Prior to obtaining the samples from Tank 50H, a single pump was run at least 4.4 hours and the samples were pulled immediately after pumpmore » shut down. All volatile organic analysis (VOA) and semi-volatile organic analysis (SVOA) were performed on the surface sample and all other analyses were performed on the variable depth sample. The information from this characterization will be used by Savannah River Remediation (SRR) for the transfer of aqueous waste from Tank 50H to the Saltstone Production Facility, where the waste will be treated and disposed of in the Saltstone Disposal Facility. This memorandum compares results, where applicable, to Saltstone Waste Acceptance Criteria (WAC) limits and targets. The chemical and radionuclide contaminant results from the characterization of the First Quarter CY17 sampling of Tank 50H were requested by SRR personnel and details of the testing are presented in the SRNL Task Technical and Quality Assurance Plan (TTQAP). This memorandum is part of Deliverable 2 from SRR request. Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals will be documented at a later time per the TTQAP for the Tank 50H saltstone task.« less

Delisting petition for 300-M saltstone (treated F006 sludge) from the 300-M liquid effluent treatment facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1989-04-04

This petition seeks exclusion for stabilized and solidified sludge material generated by treatment of wastewater from the 300-M aluminum forming and metal finishing processes. The waste contains both hazardous and radioactive components and is classified as a mixed waste. The objective of this petition is to demonstrate that the stabilized sludge material (saltstone), when properly disposed, will not exceed the health-based standards for the hazardous constituents. This petition contains sampling and analytical data which justify the request for exclusion. The results show that when the data are applied to the EPA Vertical and Horizontal Spread (VHS) Model, health-based standards formore » all hazardous waste constituents will not be exceeded during worst case operating and environmental conditions. Disposal of the stabilized sludge material in concrete vaults will meet the requirements pertaining to Waste Management Activities for Groundwater Protection at the Savannah River Site in Aiken, S.C. Documents set forth performance objectives and disposal options for low-level radioactive waste disposal. Concrete vaults specified for disposal of 300-M saltstone (treated F006 sludge) assure that these performance objectives will be met.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pickenheim, B.; Hansen, E.; Leishear, R.

A 10-inch READCO mixer is used for mixing the premix (45 (wt%) fly ash, 45 wt% slag, and 10 wt% portland cement) with salt solution in the Saltstone Production Facility (SPF). The Saltstone grout free falls into the grout hopper which feeds the suction line leading to the Watson SPX 100 duplex hose pump. The Watson SPX 100 pumps the grout through approximately 1500 feet of piping prior to being discharged into the Saltstone Disposal Facility (SDF) vaults. The existing grout hopper has been identified by the Saltstone Enhanced Low Activity Waste Disposal (ELAWD) project for re-design. The current nominalmore » working volume of this hopper is 12 gallons and does not permit handling an inadvertent addition of excess dry feeds. Saltstone Engineering has proposed a new hopper tank that will have a nominal working volume of 300 gallons and is agitated with a mechanical agitator. The larger volume hopper is designed to handle variability in the output of the READCO mixer and process upsets without entering set back during processing. The objectives of this task involve scaling the proposed hopper design and testing the scaled hopper for the following processing issues: (1) The effect of agitation on radar measurement. Formation of a vortex may affect the ability to accurately measure the tank level. The agitator was run at varying speeds and with varying grout viscosities to determine what parameters cause vortex formation and whether measurement accuracy is affected. (2) A dry feeds over addition. Engineering Calculating X-ESR-Z-00017 1 showed that an additional 300 pounds of dry premix added to a 300 gallon working volume would lower the water to premix ratio (W/P) from the nominal 0.60 to 0.53 based on a Salt Waste Processing Facility (SWPF) salt simulant. A grout with a W/P of 0.53 represents the upper bound of grout rheology that could be processed at the facility. A scaled amount of dry feeds will be added into the hopper to verify that this is a recoverable situation. (3) The necessity of baffles in the hopper. The preference of the facility is not to have baffles in the hopper; however, if the initial testing indicates inadequate agitation or difficulties with the radar measurement, baffles will be tested.« less

Winter Severe Weather: A Case Study of the Intense Squall Line of 6-7 January 1995 in the Carolinas

DTIC Science & Technology

1996-01-01

line. 51 U- U- )C nM-,L Cz2r r Zr’.r - -52 cz bi2 0z CPIu Inu leu bts 533 rMPF DWPF 39 36- 30------- - - - - - - - - - - - - PMiL 014- Gusr DARR 10- 6...14u cz lo0 Go0 Go a- Nr, lou 58 ,t, 7!Ch 59 Lr, CC 7 ~ cr cz 60 z u-, II Zn zc z 11 L1X - CL Aar- c- 61 100 CCu ac- Go 62 mm IflIN Z N _ m 63 TMPF DWPF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raszewski, F; Tommy Edwards, T; David Peeler, D

Sludge Batch 4 (SB4) is currently being processed in the Defense Waste Processing Facility (DWPF) using Frit 510. The slurry pumps in Tank 40 are experiencing in-leakage of bearing water, which is causing the sludge slurry feed in Tank 40 to become dilute at a rapid rate. Currently, the DWPF is removing this dilution water by performing caustic boiling during the Sludge Receipt and Adjustment Tank (SRAT) cycle. In order to alleviate prolonged SRAT cycle times that may eventually impact canister production rates, decant scenarios of 100, 150, and 200 kilogallons of supernate were proposed for Tank 40 during themore » DWPF March outage. Based on the results of the preliminary assessment issued by the Savannah River National Laboratory (SRNL), the Liquid Waste Organization (LWO) issued a Technical Task Request (TTR) for SRNL to (1) perform a more detailed evaluation using updated SB4 compositional information and (2) assess the viability of Frit 510 and determine any potential impacts on the SB4 system. As defined in the TTR, LWO requested that SRNL validate the sludge--only SB4 flowsheet and the coupled operations flowsheet using the 100K gallon decant volume as well as the addition of 3 wt% sodium on a calcined oxide basis. Approximately 12 historical glasses were identified during a search of the ComProTM database that are located within at least one of the five glass regions defined by the proposed SB4 flowsheet options. While these glasses meet the requirements of a variability study there was some concern that the compositional coverage did not adequately bound all cases. Therefore, SRNL recommended that a supplemental experimental variability study be performed to support the various SB4 flowsheet options that may be implemented for future SB4 operations in DWPF. Eighteen glasses were selected based on nominal sludge projections representing the current as well as the proposed flowsheets over a WL interval of interest to DWPF (32-42%). The intent of the experimental portion of the variability study is to demonstrate that the glasses of the Frit 510-modified SB4 compositional region (Cases No.1-5) are both acceptable relative to the Environmental Assessment (EA) reference glass and predictable by the current DWPF process control models for durability. Frit 510 is a viable option for the processing of SB4 after a Tank 40 decant and the addition of products from the Actinide Removal Process (ARP). The addition of ARP did not have any negative impacts on the acceptability and predictability of the variability study glasses. The results of the variability study indicate that all of the study glasses (both quenched and centerline canister cooled (ccc)) have normalized releases for boron that are well below the reference EA glass (16.695 g/L). The durabilities of all of the study glasses are predictable using the current Product Composition Control System (PCCS) durability models with the exception of SB4VAR24ccc (Case No.2 at 41%). PCCS is not applicable to non-homogeneous glasses (i.e. glasses containing crystals such as acmite and nepheline), thus SB4VAR24ccc should not be predictable as it contains nepheline. The presence of nepheline has been confirmed in both SB4VAR13ccc and SB4VAR24ccc by X-ray diffraction (XRD). These two glasses are the first results which indicate that the current nepheline discriminator value of 0.62 is not conservative. The nepheline discriminator was implemented into PCCS for SB4 based on the fact that all of the historical glasses evaluated with nepheline values of 0.62 or greater did not contain nepheline via XRD analysis. Although these two glasses do cause some concern over the use of the 0.62 nepheline value for future DWPF glass systems, the impact to the current SB4 system is of little concern. More specifically, the formation of nepheline was observed in glasses targeting 41 or 42% WL. Current processing of the Frit 510-SB4 system in DWPF has nominally targeted 34% WL. For the SB4 variability study glasses targeting these lower WLs, nepheline formation was not observed and the minimal difference in PCT response between quenched and ccc versions supported its absence.« less

DWPF Safely Dispositioning Liquid Waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2016-01-05

The only operating radioactive waste glassification plant in the nation, the Defense Waste Processing Facility (DWPF) converts the liquid radioactive waste currently stored at the Savannah River Site (SRS) into a solid glass form suitable for long-term storage and disposal. Scientists have long considered this glassification process, called “vitrification,” as the preferred option for treating liquid radioactive waste.

Phase Stability Determinations of DWPF Waste Glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marra, S.L.

1999-10-22

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. To fulfill this requirement, glass samples were heat treated at various times and temperatures. These results will provide guidance to the repository program about conditions to be avoided during shipping, handling and storage of DWPF canistered waste forms.

Material Compatibility Evaluation for DWPF Nitric-Glycolic Acid - Literature Review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J. I.; Skidmore, T. E.

Glycolic acid is being evaluated as an alternative for formic and nitric acid in the DWPF flowsheet. Demonstration testing and modeling for this new flowsheet has shown that glycolic acid and glycolate has a potential to remain in certain streams generated during the production of the nuclear waste glass. A literature review was conducted to assess the impact of glycolic acid on the corrosion of the materials of construction for the DWPF facility as well as facilities downstream which may have residual glycolic acid and glycolates present. The literature data was limited to solutions containing principally glycolic acid. The reportedmore » corrosion rates and degradation characteristics have shown the following for the materials of construction.« less

Measures for Assessing Student Attitudes toward Older People

ERIC Educational Resources Information Center

Lin, Xiaoping; Bryant, Christina; Boldero, Jennifer

2011-01-01

Measuring medical and allied health students' attitudes towards older people has been identified as an important research area. The present study compared the use of implicit and explicit attitude measures. Sixty-five undergraduates completed one explicit measure, the Fraboni Scale of Ageism (FSA), (Fraboni, Saltstone, & Hughes, 1990) and one…

DWPF Safely Dispositioning Liquid Waste

ScienceCinema

None

2018-06-21

The only operating radioactive waste glassification plant in the nation, the Defense Waste Processing Facility (DWPF) converts the liquid radioactive waste currently stored at the Savannah River Site (SRS) into a solid glass form suitable for long-term storage and disposal. Scientists have long considered this glassification process, called “vitrification,” as the preferred option for treating liquid radioactive waste.

SIMULANT DEVELOPMENT FOR SAVANNAH RIVER SITE HIGH LEVEL WASTE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M; Russell Eibling, R; David Koopman, D

2007-09-04

The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies High Level Waste (HLW) for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. The HLW consists of insoluble metal hydroxides (primarily iron, aluminum, magnesium, manganese, and uranium) and soluble sodium salts (carbonate, hydroxide, nitrite, nitrate, and sulfate). The HLW is processed in large batches through DWPF; DWPF has recently completed processing Sludge Batch 3 (SB3) and is currently processing Sludge Batch 4 (SB4). The composition of metal species in SB4 is shown in Table 1 as a function of the ratiomore » of a metal to iron. Simulants remove radioactive species and renormalize the remaining species. Supernate composition is shown in Table 2.« less

ROLE OF MANGANESE REDUCTION/OXIDATION (REDOX) ON FOAMING AND MELT RATE IN HIGH LEVEL WASTE (HLW) MELTERS (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C; Michael Stone, M

2007-03-30

High-level nuclear waste is being immobilized at the Savannah River Site (SRS) by vitrification into borosilicate glass at the Defense Waste Processing Facility (DWPF). Control of the Reduction/Oxidation (REDOX) equilibrium in the DWPF melter is critical for processing high level liquid wastes. Foaming, cold cap roll-overs, and off-gas surges all have an impact on pouring and melt rate during processing of high-level waste (HLW) glass. All of these phenomena can impact waste throughput and attainment in Joule heated melters such as the DWPF. These phenomena are caused by gas-glass disequilibrium when components in the melter feeds convert to glass andmore » liberate gases such as H{sub 2}O vapor (steam), CO{sub 2}, O{sub 2}, H{sub 2}, NO{sub x}, and/or N{sub 2}. During the feed-to-glass conversion in the DWPF melter, multiple types of reactions occur in the cold cap and in the melt pool that release gaseous products. The various gaseous products can cause foaming at the melt pool surface. Foaming should be avoided as much as possible because an insulative layer of foam on the melt surface retards heat transfer to the cold cap and results in low melt rates. Uncontrolled foaming can also result in a blockage of critical melter or melter off-gas components. Foaming can also increase the potential for melter pressure surges, which would then make it difficult to maintain a constant pressure differential between the DWPF melter and the pour spout. Pressure surges can cause erratic pour streams and possible pluggage of the bellows as well. For these reasons, the DWPF uses a REDOX strategy and controls the melt REDOX between 0.09 {le} Fe{sup 2+}/{summation}Fe {le} 0.33. Controlling the DWPF melter at an equilibrium of Fe{sup +2}/{summation}Fe {le} 0.33 prevents metallic and sulfide rich species from forming nodules that can accumulate on the floor of the melter. Control of foaming, due to deoxygenation of manganic species, is achieved by converting oxidized MnO{sub 2} or Mn{sub 2}O{sub 3} species to MnO during melter preprocessing. At the lower redox limit of Fe{sup +2}/{summation}Fe {approx} 0.09 about 99% of the Mn{sup +4}/Mn{sup +3} is converted to Mn{sup +2}. Therefore, the lower REDOX limits eliminates melter foaming from deoxygenation.« less

Technical Insights for Saltstone PA Maintenance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flach, G.; Sarkar, S.; Mahadevan, S.

2011-07-20

The Cementitious Barriers Partnership (CBP) is a collaborative program sponsored by the US DOE Office of Waste Processing. The objective of the CBP is to develop a set of computational tools to improve understanding and prediction of the long-term structural, hydraulic, and chemical performance of cementitious barriers and waste forms used in nuclear applications. CBP tools are expected to better characterize and reduce the uncertainties of current methodologies for assessing cementitious barrier performance and increase the consistency and transparency of the assessment process, as the five-year program progresses. In September 2009, entering its second year of funded effort, the CBPmore » sought opportunities to provide near-term tangible support to DOE Performance Assessments (PAs). The Savannah River Saltstone Disposal Facility (SDF) was selected for the initial PA support effort because (1) cementitious waste forms and barriers play a prominent role in the performance of the facility, (2) certain important long-term behaviors of cementitious materials composing the facility are uncertain, (3) review of the SDF PA by external stakeholders is ongoing, and (4) the DOE contractor responsible for the SDF PA is open to receiving technical assistance from the CBP. A review of the current (SRR Closure & Waste Disposal Authority 2009) and prior Saltstone PAs (e.g., Cook et al. 2005) suggested five potential opportunities for improving predictions. The candidate topics considered were (1) concrete degradation from external sulfate attack, (2) impact of atmospheric exposure to concrete and grout before closure, such as accelerated slag and Tc-99 oxidation, (3) mechanistic prediction of geochemical conditions, (4) concrete degradation from rebar corrosion due to carbonation, and (5) early age cracking from drying and/or thermal shrinkage. The candidate topics were down-selected considering the feasibility of addressing each issue within approximately six months, and compatibility with existing CBP expertise and already-planned activities. Based on these criteria, the five original topics were down-selected to two: external sulfate attack and mechanistic geochemical prediction. For each of the selected topics, the CBP communicated with the PA analysts and subject matter experts at Savannah River to acquire input data specific to the Saltstone facility and related laboratory experiments. Simulations and analyses were performed for both topics using STADIUM (SIMCO 2008), LeachXS/ORCHESTRA (ECN 2007, Meeussen 2003), and other software tools. These supplemental CBP analyses produced valuable technical insights that can be used to strengthen the Saltstone PA using the ongoing PA maintenance process. This report in part summarizes key information gleaned from more comprehensive documents prepared by Sarkar et al. (2010), Samson (2010), and Sarkar (2010).« less

Short Term Weather Forecasting in Real Time in a Base Weather Station Setting

DTIC Science & Technology

1993-10-01

SMSL DWPF Figure 25. Plot of surface airways observations at 18 UTC, I April 1993. Data is plotted in conventional notation. 35 mu eb 23 -:.-j-32 29292 3...34 38 3 ... .. :......:.. . . O0i-02-93 0600 GMT CLCT TMPF WSYM SMSL DWPF Figure 26. As in Figure 25, except for 06 UTC, 2 April 1993. 36 Figure 27

Examination Of Sulfur Measurements In DWPF Sludge Slurry And SRAT Product Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.; Wiedenman, B. J.

2012-11-29

Savannah River National Laboratory (SRNL) was asked to re-sample the received SB7b WAPS material for wt. % solids, perform an aqua regia digestion and analyze the digested material by inductively coupled plasma - atomic emission spectroscopy (ICP-AES), as well as re-examine the supernate by ICP-AES. The new analyses were requested in order to provide confidence that the initial analytical subsample was representative of the Tank 40 sample received and to replicate the S results obtained on the initial subsample collected. The ICP-AES analyses for S were examined with both axial and radial detection of the sulfur ICP-AES spectroscopic emission linesmore » to ascertain if there was any significant difference in the reported results. The outcome of this second subsample of the Tank 40 WAPS material is the first subject of this report. After examination of the data from the new subsample of the SB7b WAPS material, a team of DWPF and SRNL staff looked for ways to address the question of whether there was in fact insoluble S that was not being accounted for by ion chromatography (IC) analysis. The question of how much S is reaching the melter was thought best addressed by examining a DWPF Slurry Mix Evaporator (SME) Product sample, but the significant dilution of sludge material, containing the S species in question, that results from frit addition was believed to add additional uncertainty to the S analysis of SME Product material. At the time of these discussions it was believed that all S present in a Sludge Receipt and Adjustment Tank (SRAT) Receipt sample would be converted to sulfate during the course of the SRAT cycle. A SRAT Product sample would not have the S dilution effect resulting from frit addition, and hence, it was decided that a DWPF SRAT Product sample would be obtained and submitted to SRNL for digestion and sample preparation followed by a round-robin analysis of the prepared samples by the DWPF Laboratory, F/H Laboratories, and SRNL for S and sulfate. The results of this round-robin analytical study are the second subject of this report.« less

Nitric-glycolic flowsheet testing for maximum hydrogen generation rate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martino, C. J.; Newell, J. D.; Williams, M. S.

The Defense Waste Processing Facility (DWPF) at the Savannah River Site is developing for implementation a flowsheet with a new reductant to replace formic acid. Glycolic acid has been tested over the past several years and found to effectively replace the function of formic acid in the DWPF chemical process. The nitric-glycolic flowsheet reduces mercury, significantly lowers the chemical generation of hydrogen and ammonia, allows purge reduction in the Sludge Receipt and Adjustment Tank (SRAT), stabilizes the pH and chemistry in the SRAT and the Slurry Mix Evaporator (SME), allows for effective adjustment of the SRAT/SME rheology, and is favorablemore » with respect to melter flammability. The objective of this work was to perform DWPF Chemical Process Cell (CPC) testing at conditions that would bound the catalytic hydrogen production for the nitric-glycolic flowsheet.« less

2013 CEF RUN - PHASE 1 DATA ANALYSIS AND MODEL VALIDATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, A.

2014-05-08

Phase 1 of the 2013 Cold cap Evaluation Furnace (CEF) test was completed on June 3, 2013 after a 5-day round-the-clock feeding and pouring operation. The main goal of the test was to characterize the CEF off-gas produced from a nitric-formic acid flowsheet feed and confirm whether the CEF platform is capable of producing scalable off-gas data necessary for the revision of the DWPF melter off-gas flammability model; the revised model will be used to define new safety controls on the key operating parameters for the nitric-glycolic acid flowsheet feeds including total organic carbon (TOC). Whether the CEF off-gas datamore » were scalable for the purpose of predicting the potential flammability of the DWPF melter exhaust was determined by comparing the predicted H{sub 2} and CO concentrations using the current DWPF melter off-gas flammability model to those measured during Phase 1; data were deemed scalable if the calculated fractional conversions of TOC-to-H{sub 2} and TOC-to-CO at varying melter vapor space temperatures were found to trend and further bound the respective measured data with some margin of safety. Being scalable thus means that for a given feed chemistry the instantaneous flow rates of H{sub 2} and CO in the DWPF melter exhaust can be estimated with some degree of conservatism by multiplying those of the respective gases from a pilot-scale melter by the feed rate ratio. This report documents the results of the Phase 1 data analysis and the necessary calculations performed to determine the scalability of the CEF off-gas data. A total of six steady state runs were made during Phase 1 under non-bubbled conditions by varying the CEF vapor space temperature from near 700 to below 300°C, as measured in a thermowell (T{sub tw}). At each steady state temperature, the off-gas composition was monitored continuously for two hours using MS, GC, and FTIR in order to track mainly H{sub 2}, CO, CO{sub 2}, NO{sub x}, and organic gases such as CH{sub 4}. The standard deviation of the average vapor space temperature during each steady state ranged from 2 to 6°C; however, those of the measured off-gas data were much larger due to the inherent cold cap instabilities in the slurry-fed melters. In order to predict the off-gas composition at the sampling location downstream of the film cooler, the measured feed composition was charge-reconciled and input into the DWPF melter off-gas flammability model, which was then run under the conditions for each of the six Phase 1 steady states. In doing so, it was necessary to perform an overall heat/mass balance calculation from the melter to the Off-Gas Condensate Tank (OGCT) in order to estimate the rate of air inleakage as well as the true gas temperature in the CEF vapor space (T{sub gas}) during each steady state by taking into account the effects of thermal radiation on the measured temperature (T{sub tw}). The results of Phase 1 data analysis and subsequent model runs showed that the predicted concentrations of H{sub 2} and CO by the DWPF model correctly trended and further bounded the respective measured data in the CEF off-gas by over predicting the TOC-to-H{sub 2} and TOC-to-CO conversion ratios by a factor of 2 to 5; an exception was the 7X over prediction of the latter at T{sub gas} = 371°C but the impact of CO on the off-gas flammability potential is only minor compared to that of H{sub 2}. More importantly, the seemingly-excessive over prediction of the TOC-to-H{sub 2} conversion by a factor of 4 or higher at T{sub gas} < ~350°C was attributed to the conservative antifoam decomposition scheme added recently to the model and therefore is considered a modeling issue and not a design issue. At T{sub gas} > ~350°C, the predicted TOC-to-H{sub 2} conversions were closer to but still higher than the measured data by a factor of 2, which may be regarded as adequate from the safety margin standpoint. The heat/mass balance calculations also showed that the correlation between T{sub tw} and T{sub gas} in the CEF vapor space was close to that of the ½ scale SGM, whose data were taken as directly applicable to the DWPF melter and thus used to set all the parameters of the original model. Based on these results of the CEF Phase 1 off-gas and thermal data analyses, it is concluded that: (1) The thermal characteristics of the CEF vapor space are prototypic thanks to its prototypic design; and (2) The CEF off-gas data are scalable in terms of predicting the flammability potential of the DWPF melter off-gas. These results also show that the existing DWPF safety controls on the TOC and antifoam as a function of nitrate are conservative by the same order of magnitude shown by the Phase 1 data at T{sub gas} < ~350°C, since they were set at T{sub gas} = 294°C, which falls into the region of excessive conservatism for the current DWPF model in terms of predicting the TOC-to-H{sub 2} conversion. In order to remedy the overly-conservative antifoam decomposition scheme used in the current DWPF model, the data from two recent tests will be analyzed in detail in order to gain additional insights into the antifoam decomposition chemistry in the cold cap. The first test was run in a temperature-programmed furnace using both normal and spiked feeds with fresh antifoam under inert and slightly oxidizing vapor space conditions. Phase 2 of the CEF test was run with the baseline nitric-glycolic acid flowsheet feeds that contained the “processed antifoam” and those spiked with fresh antifoam in order to study the effects of antifoam concentration as well as processing history on its decomposition chemistry under actual melter conditions. The goal is to develop an improved antifoam decomposition model from the analysis of these test data and incorporate it into a new multistage cold cap model to be developed concurrently for the nitric-glycolic acid flowsheet feeds. These activities will be documented in the Phase 2 report. Finally, it is recommended that some of the conservatism in the existing DWPF safety controls be removed by improving the existing measured-vs.-true gas temperature correlation used in the melter vapor space combustion calculations. The basis for this recommendation comes from the fact that the existing correlation was developed by linearly extrapolating the SGM data taken over a relatively narrow temperature range down to the safety basis minimum of 460°C, thereby under predicting the true gas temperature considerably, as documented in this report. Specifically, the task of improving the current temperature correlation will involve; (1) performing a similar heat/mass balance analysis used in this study on actual DWPF data, (2) validating the measured-vs.-true gas temperature correlation for the CEF developed in this study against the DWPF melter heat/mass balance results, and (3) making adjustments to the CEF correlation, if necessary, before incorporating it into the DWPF safety basis calculations. The steps described here can be completed with relatively minimum efforts.« less

Literature Review: Assessment of DWPF Melter and Melter Off-gas System Lifetime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reigel, M.

2015-07-30

Testing to date for the MOC for the Hanford Waste Treatment and Immobilization Plant (WTP) melters is being reviewed with the lessons learned from DWPF in mind and with consideration to the changes in the flowsheet/feed compositions that have occurred since the original testing was performed. This information will be presented in a separate technical report that identifies any potential gaps for WTP processing.

Assessment of the impact of the next generation solvent on DWPF melter off-gas flammability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, W. E.

2013-02-13

An assessment has been made to evaluate the impact on the DWPF melter off-gas flammability of replacing the current solvent used in the Modular Caustic-Side Solvent Extraction Process Unit (MCU) process with the Next Generation Solvent (NGS-MCU) and blended solvent. The results of this study showed that the concentrations of nonvolatile carbon and hydrogen of the current solvent in the Slurry Mix Evaporator (SME) product would both be about 29% higher than their counterparts of the NGS-MCU and blended solvent in the absence of guanidine partitioning. When 6 ppm of guanidine (TiDG) was added to the effluent transfer to DWPFmore » to simulate partitioning for the NGS-MCU and blended solvent cases and the concentration of Isopar{reg_sign} L in the effluent transfer was controlled below 87 ppm, the concentrations of nonvolatile carbon and hydrogen of the NGS-MCU and blended solvent were still about 12% and 4% lower, respectively, than those of the current solvent. It is, therefore, concluded that as long as the volume of MCU effluent transfer to DWPF is limited to 15,000 gallons per Sludge Receipt and Adjustment Tank (SRAT)/SME cycle and the concentration of Isopar{reg_sign} L in the effluent transfer is controlled below 87 ppm, using the current solvent assumption of 105 ppm Isopar{reg_sign} L or 150 ppm solvent in lieu of NGS-MCU or blended solvent in the DWPF melter off-gas flammability assessment is conservative for up to an additional 6 ppm of TiDG in the effluent due to guanidine partitioning. This report documents the calculations performed to reach this conclusion.« less

Defense Waste Processing Facility (DWPF) Durability-Composition Models and the Applicability of the Associated Reduction of Constraints (ROC) Criteria for High TiO 2 Containing Glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C. M.; Edwards, T. B.; Trivelpiece, C. L.

Radioactive high-level waste (HLW) at the Savannah River Site (SRS) has successfully been vitrified into borosilicate glass in the DWPF since 1996. Vitrification requires stringent product/process (P/P) constraints since the glass cannot be reworked once it has been poured into ten foot tall by two foot diameter canisters. A unique “feed forward” statistical process control (SPC) was developed for this control rather than relying on statistical quality control (SQC). In SPC, the feed composition to the DWPF melter is controlled prior to vitrification. In SQC, the glass product would be sampled after it is vitrified. Individual glass property-composition models formmore » the basis for the “feed forward” SPC. The models transform constraints on the melt and glass properties into constraints on the feed composition going to the melter in order to determine, at the 95% confidence level, that the feed will be processable and that the durability of the resulting waste form will be acceptable to a geologic repository. The DWPF SPC system is known as the Product Composition Control System (PCCS). One of the process models within PCCS is known as the Thermodynamic Hydration Energy Reaction MOdel (THERMO™). The DWPF will soon be receiving increased concentrations of TiO 2-, Na 2O-, and Cs 2O-enriched wastes from the Salt Waste Processing Facility (SWPF). The SWPF has been built to pretreat the high-curie fraction of the salt waste to be removed from the HLW tanks in the F- and H-Area Tank Farms at the SRS. In order to validate the existing TiO 2 term in THERMO™ beyond 2.0 wt% in the DWPF, new durability data were developed over the target range of 2.00 to 6.00 wt% TiO 2 and evaluated against the 1995 durability model. The durability was measured by the 7-day Product Consistency Test. This study documents the adequacy of the existing THERMO™ terms. It is recommended that the modified THERMO™ durability models and the modified property acceptable region limits for the durability constraints be incorporated in the next revision of the technical bases for PCCS and then implemented into PCCS. It is also recommended that an reduction of constraints of 4 wt% Al 2O 3 be implemented with no restrictions on the amount of alkali in the glass for TiO 2 values ≥2 wt%. The ultimate limit on the amount of TiO 2 that can be accommodated from SWPF will be determined by the three PCCS models, the waste composition of a given sludge batch, the waste loading of the sludge batch, and the frit used for vitrification.« less

Corrosion Testing of Monofrax K-3 Refractory in Defense Waste Processing Facility (DWPF) Alternate Reductant Feeds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, M.; Jantzen, C.; Burket, P.

The Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) uses a combination of reductants and oxidants while converting high level waste (HLW) to a borosilicate waste form. A reducing flowsheet is maintained to retain radionuclides in their reduced oxidation states which promotes their incorporation into borosilicate glass. For the last 20 years of processing, the DWPF has used formic acid as the main reductant and nitric acid as the main oxidant. During reaction in the Chemical Process Cell (CPC), formate and formic acid release measurably significant H 2 gas which requires monitoring of certain vessel’s vapor spaces.more » A switch to a nitric acid-glycolic acid (NG) flowsheet from the nitric-formic (NF) flowsheet is desired as the NG flowsheet releases considerably less H 2 gas upon decomposition. This would greatly simplify DWPF processing from a safety standpoint as close monitoring of the H 2 gas concentration could become less critical. In terms of the waste glass melter vapor space flammability, the switch from the NF flowsheet to the NG flowsheet showed a reduction of H 2 gas production from the vitrification process as well. Due to the positive impact of the switch to glycolic acid determined on the flammability issues, evaluation of the other impacts of glycolic acid on the facility must be examined.« less

Integration of the Uncertainties of Anion and TOC Measurements into the Flammability Control Strategy for Sludge Batch 8 at the DWPF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T. B.

2013-03-14

The Savannah River National Laboratory (SRNL) has been working with the Savannah River Remediation (SRR) Defense Waste Processing Facility (DWPF) in the development and implementation of a flammability control strategy for DWPF’s melter operation during the processing of Sludge Batch 8 (SB8). SRNL’s support has been in response to technical task requests that have been made by SRR’s Waste Solidification Engineering (WSE) organization. The flammability control strategy relies on measurements that are performed on Slurry Mix Evaporator (SME) samples by the DWPF Laboratory. Measurements of nitrate, oxalate, formate, and total organic carbon (TOC) standards generated by the DWPF Laboratory aremore » presented in this report, and an evaluation of the uncertainties of these measurements is provided. The impact of the uncertainties of these measurements on DWPF’s strategy for controlling melter flammability also is evaluated. The strategy includes monitoring each SME batch for its nitrate content and its TOC content relative to the nitrate content and relative to the antifoam additions made during the preparation of the SME batch. A linearized approach for monitoring the relationship between TOC and nitrate is developed, equations are provided that integrate the measurement uncertainties into the flammability control strategy, and sample calculations for these equations are shown to illustrate the impact of the uncertainties on the flammability control strategy.« less

DWPF Recycle Evaporator Simulant Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M

2005-04-05

Testing was performed to determine the feasibility and processing characteristics of an evaporation process to reduce the volume of the recycle stream from the Defense Waste Processing Facility (DWPF). The concentrated recycle would be returned to DWPF while the overhead condensate would be transferred to the Effluent Treatment Plant. Various blends of evaporator feed were tested using simulants developed from characterization of actual recycle streams from DWPF and input from DWPF-Engineering. The simulated feed was evaporated in laboratory scale apparatus to target a 30X volume reduction. Condensate and concentrate samples from each run were analyzed and the process characteristics (foaming,more » scaling, etc) were visually monitored during each run. The following conclusions were made from the testing: Concentration of the ''typical'' recycle stream in DWPF by 30X was feasible. The addition of DWTT recycle streams to the typical recycle stream raises the solids content of the evaporator feed considerably and lowers the amount of concentration that can be achieved. Foaming was noted during all evaporation tests and must be addressed prior to operation of the full-scale evaporator. Tests were conducted that identified Dow Corning 2210 as an antifoam candidate that warrants further evaluation. The condensate has the potential to exceed the ETP WAC for mercury, silicon, and TOC. Controlling the amount of equipment decontamination recycle in the evaporator blend would help meet the TOC limits. The evaporator condensate will be saturated with mercury and elemental mercury will collect in the evaporator condensate collection vessel. No scaling on heating surfaces was noted during the tests, but splatter onto the walls of the evaporation vessels led to a buildup of solids. These solids were difficult to remove with 2M nitric acid. Precipitation of solids was not noted during the testing. Some of the aluminum present in the recycle streams was converted from gibbsite to aluminum oxide during the evaporation process. The following recommendations were made: Recycle from the DWTT should be metered in slowly to the ''typical'' recycle streams to avoid spikes in solids content to allow consistent processing and avoid process upsets. Additional studies should be conducted to determine acceptable volume ratios for the HEME dissolution and decontamination solutions in the evaporator feed. Dow Corning 2210 antifoam should be evaluated for use to control foaming. Additional tests are required to determine the concentration of antifoam required to prevent foaming during startup, the frequency of antifoam additions required to control foaming during steady state processing, and the ability of the antifoam to control foam over a range of potential feed compositions. This evaluation should also include evaluation of the degradation of the antifoam and impact on the silicon and TOC content of the condensate. The caustic HEME dissolution recycle stream should be neutralized to at least pH of 7 prior to blending with the acidic recycle streams. Dow Corning 2210 should be used during the evaporation testing using the radioactive recycle samples received from DWPF. Evaluation of additional antifoam candidates should be conducted as a backup for Dow Corning 2210. A camera and/or foam detection instrument should be included in the evaporator design to allow monitoring of the foaming behavior during operation. The potential for foam formation and high solids content should be considered during the design of the evaporator vessel.« less

Antifoam degradation testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D. P.; Zamecnik, J. R.; Newell, D. D.

2015-08-20

This report describes the results of testing to quantify the degradation products resulting from the dilution and storage of Antifoam 747. Antifoam degradation is of concern to the Defense Waste Processing Facility (DWPF) due to flammable decomposition products in the vapor phase of the Chemical Process Cell vessels, as well as the collection of flammable and organic species in the offgas condensate. The discovery that hexamethyldisiloxane is formed from the antifoam decomposition was the basis for a Potential Inadequacy in the Safety Analysis declaration by the DWPF.

SLURRY MIX EVAPORATOR BATCH ACCEPTABILITY AND TEST CASES OF THE PRODUCT COMPOSITION CONTROL SYSTEM WITH THORIUM AS A REPORTABLE ELEMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.

2010-10-07

The Defense Waste Processing Facility (DWPF), which is operated by Savannah River Remediation, LLC (SRR), has recently begun processing Sludge Batch 6 (SB6) by combining it with Frit 418 at a nominal waste loading (WL) of 36%. A unique feature of the SB6/Frit 418 glass system, as compared to the previous glass systems processed in DWPF, is that thorium will be a reportable element (i.e., concentrations of elemental thorium in the final glass product greater than 0.5 weight percent (wt%)) for the resulting wasteform. Several activities were initiated based upon this unique aspect of SB6. One of these was anmore » investigation into the impact of thorium on the models utilized in DWPF's Product Composition and Control System (PCCS). While the PCCS is described in more detail below, for now note that it is utilized by Waste Solidification Engineering (WSE) to evaluate the acceptability of each batch of material in the Slurry Mix Evaporator (SME) before this material is passed on to the melter. The evaluation employs models that predict properties associated with processability and product quality from the composition of vitrified samples of the SME material. The investigation of the impact of thorium on these models was conducted by Peeler and Edwards [1] and led to a recommendation that DWPF can process the SB6/Frit 418 glass system with ThO{sub 2} concentrations up to 1.8 wt% in glass. Questions also arose regarding the handling of thorium in the SME batch acceptability process as documented by Brown, Postles, and Edwards [2]. Specifically, that document is the technical bases of PCCS, and while Peeler and Edwards confirmed the reliability of the models, there is a need to confirm that the current implementation of DWPF's PCCS appropriately handles thorium as a reportable element. Realization of this need led to a Technical Task Request (TTR) prepared by Bricker [3] that identified some specific SME-related activities that the Savannah River National Laboratory (SRNL) was requested to conduct. SRNL issued a Task Technical and Quality Assurance (TT&QA) plan [4] in response to the SRR request. The conclusions provided in this report are that no changes need to be made to the SME acceptability process (i.e., no modifications to WSRC-TR-95-00364, Revision 5, are needed) and no changes need to be made to the Product Composition Control System (PCCS) itself (i.e. the spreadsheet utilized by Waste Solidification Engineering (WSE) for acceptability decisions does not require modification) in response to thorium becoming a reportable element for DWPF operations. In addition, the inputs and results for the two test cases requested by WSE for use in confirming the successful activation of thorium as a reportable element for DWPF operations during the processing of SB6 are presented in this report.« less

DWPF DECON FRIT SUPERNATE ANALYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D.; Crawford, C.

2010-09-22

The Savannah River National Laboratory (SRNL) has been requested to perform analyses on samples of the Defense Waste Processing Facility (DWPF) decon frit slurry (i.e., supernate samples and sump solid samples). Four 1-L liquid slurry samples were provided to SRNL by Savannah River Remediation (SRR) from the 'front-end' decon activities. Additionally, two 1-L sump solids samples were provided to SRNL for compositional and physical analysis. This report contains the results of the supernate analyses, while the solids (sump and slurry) results will be reported in a supplemental report. The analytical data from the decon frit supernate indicate that all ofmore » the radionuclide, organic, and inorganic concentrations met the limits in Revision 4 of the Effluent Treatment Plant (ETP) Waste Acceptance Criteria (WAC) with the exception of boron. The ETP WAC limit for boron is 15.0 mg/L while the average measured concentration (based on quadruplicate analysis) was 15.5 mg/L. The measured concentrations of Li, Na, and Si were also relatively high in the supernate analysis. These results are consistent with the relatively high measured value of B given the compositional make-up of Frit 418. Given these results, it was speculated that either (a) Frit 418 was dissolving into the supernate or aqueous fraction and/or (b) fine frit particulates were carried forward to the analytical instrument based on the sampling procedure used (i.e., the supernate samples were not filtered - only settled with the liquid fraction being transferred with a pipette). To address this issue, a filtered supernate sample (using a 0.45 um filter) was prepared and submitted for analysis. The results of the filtered sample were consistent with 'unfiltered or settled' sample - relatively high values of B, Li, Na, and Si were found. This suggests that Frit 418 is dissolving in the liquid phase which could be enhanced by the high surface area of the frit fines or particulates in suspension. Based on the results of this study, it is recommended that DWPF re-evaluate the technical basis for the B WAC limit (the only component that exceeds the ETP WAC limit from the supernate analyses) or assess if a waiver or exception can be obtained for exceeding this limit. Given the possible dissolution of B, Li, Na, and Si into the supernate (due to dissolution of frit), DWPF may need to assess if the release of these frit components into the supernate are a concern for the disposal options being considered. It should be noted that the results of this study may not be representative of future decon frit solutions or sump/slurry solids samples. Therefore, future DWPF decisions regarding the possible disposal pathways for either the aqueous or solid portions of the Decon Frit system need to factor in the potential differences. More specifically, introduction of a different frit or changes to other DWPF flowsheet unit operations (e.g., different sludge batch or coupling with other process streams) may impact not only the results but also the conclusions regarding acceptability with respect to the ETF WAC limits.« less

DWPF Melter Off-Gas Flammability Assessment for Sludge Batch 9

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, A. S.

2016-07-11

The slurry feed to the Defense Waste Processing Facility (DWPF) melter contains several organic carbon species that decompose in the cold cap and produce flammable gases that could accumulate in the off-gas system and create potential flammability hazard. To mitigate such a hazard, DWPF has implemented a strategy to impose the Technical Safety Requirement (TSR) limits on all key operating variables affecting off-gas flammability and operate the melter within those limits using both hardwired/software interlocks and administrative controls. The operating variables that are currently being controlled include; (1) total organic carbon (TOC), (2) air purges for combustion and dilution, (3)more » melter vapor space temperature, and (4) feed rate. The safety basis limits for these operating variables are determined using two computer models, 4-stage cold cap and Melter Off-Gas (MOG) dynamics models, under the baseline upset scenario - a surge in off-gas flow due to the inherent cold cap instabilities in the slurry-fed melter.« less

HLW system plan - revision 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1994-01-14

The projected ability of the Tank Farm to support DWPF startup and continued operation has diminished somewhat since revision 1 of this Plan. The 13 month delay in DWPF startup, which actually helps the Tank Farm condition in the near term, was more than offset by the 9 month delay in ITP startup, the delay in the Evaporator startups and the reduction to Waste Removal funding. This Plan does, however, describe a viable operating strategy for the success of the HLW System and Mission, albeit with less contingency and operating flexibility than in the past. HLWM has focused resources frommore » within the division on five near term programs: The three evaporator restarts, DWPF melter heatup and completion of the ITP outage. The 1H Evaporator was restarted 12/28/93 after a 9 month shutdown for an extensive Conduct of Operations upgrade. The 2F and 2H Evaporators are scheduled to restart 3/94 and 4/94, respectively. The RHLWE startup remains 11/17/97.« less

SLUDGE WASHING AND DEMONSTRATION OF THE DWPF FLOWSHEET IN THE SRNL SHIELDED CELLS FOR SLUDGE BATCH 7A QUALIFICATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J.; Billings, A.; Click, D.

2011-07-08

Waste Solidification Engineering (WSE) has requested that characterization and a radioactive demonstration of the next batch of sludge slurry (Sludge Batch 7a*) be completed in the Shielded Cells Facility of the Savannah River National Laboratory (SRNL) via a Technical Task Request (TTR). This characterization and demonstration, or sludge batch qualification process, is required prior to transfer of the sludge from Tank 51 to the Defense Waste Processing Facility (DWPF) feed tank (Tank 40). The current WSE practice is to prepare sludge batches in Tank 51 by transferring sludge from other tanks. Discharges of nuclear materials from H Canyon are oftenmore » added to Tank 51 during sludge batch preparation. The sludge is washed and transferred to Tank 40, the current DWPF feed tank. Prior to transfer of Tank 51 to Tank 40, SRNL simulates the Tank Farm and DWPF processes with a Tank 51 sample (referred to as the qualification sample). Sludge Batch 7a (SB7a) is composed of portions of Tanks 4, 7, and 12; the Sludge Batch 6 heel in Tank 51; and a plutonium stream from H Canyon. SRNL received the Tank 51 qualification sample (sample ID HTF-51-10-125) following sludge additions to Tank 51. This report documents: (1) The washing (addition of water to dilute the sludge supernate) and concentration (decanting of supernate) of the SB7a - Tank 51 qualification sample to adjust sodium content and weight percent insoluble solids to Tank Farm projections. (2) The performance of a DWPF Chemical Process Cell (CPC) simulation using the washed Tank 51 sample. The simulation included a Sludge Receipt and Adjustment Tank (SRAT) cycle, where acid was added to the sludge to destroy nitrite and reduce mercury, and a Slurry Mix Evaporator (SME) cycle, where glass frit was added to the sludge in preparation for vitrification. The SME cycle also included replication of five canister decontamination additions and concentrations. Processing parameters were based on work with a non-radioactive simulant. (3) Vitrification of a portion of the SME product and characterization and durability testing (as measured by the Product Consistency Test (PCT)) of the resulting glass. (4) Rheology measurements of the initial slurry samples and samples after each phase of CPC processing. This program was controlled by a Task Technical and Quality Assurance Plan (TTQAP), and analyses were guided by an Analytical Study Plan. This work is Technical Baseline Research and Development (R&D) for the DWPF. It should be noted that much of the data in this document has been published in interoffice memoranda. The intent of this technical report is bring all of the SB7a related data together in a single permanent record and to discuss the overall aspects of SB7a processing.« less

EVALUATION OF ARG-1 SAMPLES PREPARED BY CESIUM CARBONATE DISSOLUTION DURING THE ISOLOK SME ACCEPTABILITY TESTING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.; Hera, K.; Coleman, C.

2011-12-05

Evaluation of Defense Waste Processing Facility (DWPF) Chemical Process Cell (CPC) cycle time identified several opportunities to improve the CPC processing time. The Mechanical Systems & Custom Equipment Development (MS&CED) Section of the Savannah River National Laboratory (SRNL) recently completed the evaluation of one of these opportunities - the possibility of using an Isolok sampling valve as an alternative to the Hydragard valve for taking DWPF process samples at the Slurry Mix Evaporator (SME). The use of an Isolok for SME sampling has the potential to improve operability, reduce maintenance time, and decrease CPC cycle time. The SME acceptability testingmore » for the Isolok was requested in Task Technical Request (TTR) HLW-DWPF-TTR-2010-0036 and was conducted as outlined in Task Technical and Quality Assurance Plan (TTQAP) SRNLRP-2011-00145. RW-0333P QA requirements applied to the task, and the results from the investigation were documented in SRNL-STI-2011-00693. Measurement of the chemical composition of study samples was a critical component of the SME acceptability testing of the Isolok. A sampling and analytical plan supported the investigation with the analytical plan directing that the study samples be prepared by a cesium carbonate (Cs{sub 2}CO{sub 3}) fusion dissolution method and analyzed by Inductively Coupled Plasma - Optical Emission Spectroscopy (ICP-OES). The use of the cesium carbonate preparation method for the Isolok testing provided an opportunity for an additional assessment of this dissolution method, which is being investigated as a potential replacement for the two methods (i.e., sodium peroxide fusion and mixed acid dissolution) that have been used at the DWPF for the analysis of SME samples. Earlier testing of the Cs{sub 2}CO{sub 3} method yielded promising results which led to a TTR from Savannah River Remediation, LLC (SRR) to SRNL for additional support and an associated TTQAP to direct the SRNL efforts. A technical report resulting from this work was issued that recommended that the mixed acid method be replaced by the Cs{sub 2}CO{sub 3} method for the measurement of magnesium (Mg), sodium (Na), and zirconium (Zr) with additional testing of the method by DWPF Laboratory being needed before further implementation of the Cs{sub 2}CO{sub 3} method at that laboratory. While the SME acceptability testing of the Isolok does not address any of the open issues remaining after the publication of the recommendation for the replacement of the mixed acid method by the Cs{sub 2}CO{sub 3} method (since those issues are to be addressed by the DWPF Laboratory), the Cs{sub 2}CO{sub 3} testing associated with the Isolok testing does provide additional insight into the performance of the method as conducted by SRNL. The performance is to be investigated by looking to the composition measurement data generated by the samples of a standard glass, the Analytical Reference Glass - 1 (ARG-1), that were prepared by the Cs{sub 2}CO{sub 3} method and included in the SME acceptability testing of the Isolok. The measurements of these samples were presented as part of the study results, but no statistical analysis of these measurements was conducted as part of those results. It is the purpose of this report to provide that analysis, which was supported using JMP Version 7.0.2.« less

Mercury in aqueous tank waste at the Savannah River Site: Facts, forms, and impacts

DOE PAGES

Bannochie, C. J.; Fellinger, T. L.; Garcia-Strickland, P.; ...

2017-03-28

Over the past two years, there has been an intense effort to understand the chemistry of mercury across the Savannah River Site’s high-level liquid waste system to determine the impacts of various mercury species. This effort started after high concentrations of mercury were measured in the leachates from a toxicity characteristic leaching procedure (TCLP) test on the low-level cementitious waste form produced in the Savannah River Saltstone facility. Speciation showed the dominant form of leached mercury to be the methylmercury cation. Neither the source of the methylmercury nor its concentration in the Saltstone feed was well established at the timemore » of the testing. Finally, this assessment of mercury was necessary to inform points in the process operations that may be subject to new separation technologies for the removal of mercury.« less

Mercury in aqueous tank waste at the Savannah River Site: Facts, forms, and impacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.; Fellinger, T. L.; Garcia-Strickland, P.

Over the past two years, there has been an intense effort to understand the chemistry of mercury across the Savannah River Site’s high-level liquid waste system to determine the impacts of various mercury species. This effort started after high concentrations of mercury were measured in the leachates from a toxicity characteristic leaching procedure (TCLP) test on the low-level cementitious waste form produced in the Savannah River Saltstone facility. Speciation showed the dominant form of leached mercury to be the methylmercury cation. Neither the source of the methylmercury nor its concentration in the Saltstone feed was well established at the timemore » of the testing. Finally, this assessment of mercury was necessary to inform points in the process operations that may be subject to new separation technologies for the removal of mercury.« less

REDUCTION OF CONSTRAINTS FOR COUPLED OPERATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raszewski, F.; Edwards, T.

2009-12-15

The homogeneity constraint was implemented in the Defense Waste Processing Facility (DWPF) Product Composition Control System (PCCS) to help ensure that the current durability models would be applicable to the glass compositions being processed during DWPF operations. While the homogeneity constraint is typically an issue at lower waste loadings (WLs), it may impact the operating windows for DWPF operations, where the glass forming systems may be limited to lower waste loadings based on fissile or heat load limits. In the sludge batch 1b (SB1b) variability study, application of the homogeneity constraint at the measurement acceptability region (MAR) limit eliminated muchmore » of the potential operating window for DWPF. As a result, Edwards and Brown developed criteria that allowed DWPF to relax the homogeneity constraint from the MAR to the property acceptance region (PAR) criterion, which opened up the operating window for DWPF operations. These criteria are defined as: (1) use the alumina constraint as currently implemented in PCCS (Al{sub 2}O{sub 3} {ge} 3 wt%) and add a sum of alkali constraint with an upper limit of 19.3 wt% ({Sigma}M{sub 2}O < 19.3 wt%), or (2) adjust the lower limit on the Al{sub 2}O{sub 3} constraint to 4 wt% (Al{sub 2}O{sub 3} {ge} 4 wt%). Herman et al. previously demonstrated that these criteria could be used to replace the homogeneity constraint for future sludge-only batches. The compositional region encompassing coupled operations flowsheets could not be bounded as these flowsheets were unknown at the time. With the initiation of coupled operations at DWPF in 2008, the need to revisit the homogeneity constraint was realized. This constraint was specifically addressed through the variability study for SB5 where it was shown that the homogeneity constraint could be ignored if the alumina and alkali constraints were imposed. Additional benefit could be gained if the homogeneity constraint could be replaced by the Al{sub 2}O{sub 3} and sum of alkali constraint for future coupled operations processing based on projections from Revision 14 of the High Level Waste (HLW) System Plan. As with the first phase of testing for sludge-only operations, replacement of the homogeneity constraint with the alumina and sum of alkali constraints will ensure acceptable product durability over the compositional region evaluated. Although these study glasses only provide limited data in a large compositional region, the approach and results are consistent with previous studies that challenged the homogeneity constraint for sludge-only operations. That is, minimal benefit is gained by imposing the homogeneity constraint if the other PCCS constraints are satisfied. The normalized boron releases of all of the glasses are well below the Environmental Assessment (EA) glass results, regardless of thermal history. Although one of the glasses had a normalized boron release of approximately 10 g/L and was not predictable, the glass is still considered acceptable. This particular glass has a low Al{sub 2}O{sub 3} concentration, which may have attributed to the anomalous behavior. Given that poor durability has been previously observed in other glasses with low Al{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} concentrations, including the sludge-only reduction of constraints study, further investigations appear to be warranted. Based on the results of this study, it is recommended that the homogeneity constraint (in its entirety with the associated low frit/high frit constraints) be eliminated for coupled operations as defined by Revision 14 of the HLW System Plan with up to 2 wt% TiO{sub 2}. The use of the alumina and sum of alkali constraints should be continued along with the variability study to determine the predictability of the current durability models and/or that the glasses are acceptable with respect to durability. The use of a variability study for each batch is consistent with the glass product control program and it will help to assess new streams or compositional changes. It is also recommended that the influence of alumina and alkali on durability be studied in greater detail. Limited data suggests that there may be a need to adjust the lower Al{sub 2}O{sub 3} limit and/or the upper alkali limit in order to prevent the fabrication of unacceptable glasses. An in-depth evaluation of all previous data as well as any new data would help to better define an alumina and alkali combination that would avoid potential phase separation and ensure glass durability.« less

Data Package for Secondary Waste Form Down-Selection—Cast Stone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Serne, R. Jeffrey; Westsik, Joseph H.

2011-09-05

Available literature on Cast Stone and Saltstone was reviewed with an emphasis on determining how Cast Stone and related grout waste forms performed in relationship to various criteria that will be used to decide whether a specific type of waste form meets acceptance criteria for disposal in the Integrated Disposal Facility (IDF) at Hanford. After the critical review of the Cast Stone/Saltstone literature, we conclude that Cast Stone is a good candidate waste form for further consideration. Cast stone meets the target IDF acceptance criteria for compressive strength, no free liquids, TCLP leachate are below the UTS permissible concentrations andmore » leach rates for Na and Tc-99 are suiteably low. The cost of starting ingredients and equipment necessary to generate Cast Stone waste forms with secondary waste streams are low and the Cast Stone dry blend formulation can be tailored to accommodate variations in liquid waste stream compositions. The database for Cast Stone short-term performance is quite extensive compared to the other three candidate waste solidification processes. The solidification of liquid wastes in Cast Stone is a mature process in comparison to the other three candidates. Successful production of Cast Stone or Saltstone has been demonstrated from lab-scale monoliths with volumes of cm3 through m3 sized blocks to 210-liter sized drums all the way to the large pours into vaults at Savannah River. To date over 9 million gallons of low activity liquid waste has been solidified and disposed in concrete vaults at Savannah River.« less

Results of an inter-laboratory study of glass formulation for the immobilization of excess plutonium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D.K.

1999-12-08

The primary focus of the current study is to determine allowable loadings of feed streams containing different ratios of plutonium, uranium, and minor components into the LaBS glass and to evaluate thermal stability with respect to the DWPF pour.

Results of Hg speciation testing on DWPF SMECT-8, OGCT-1, AND OGCT-2 samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C.

2016-02-22

The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team. The sixteenth shipment of samples was designated to include a Defense Waste Processing Facility (DWPF) Slurry Mix Evaporator Condensate Tank (SMECT) sample from Sludge Receipt and Adjustment Tank (SRAT) Batch 738 processing and two Off-Gas Condensate Tank (OGCT) samples, one following Batch 736 and one following Batch 738. The DWPF sample designations for the three samples analyzed are provided. The Batch 738 ‘End ofmore » SME Cycle’ SMECT sample was taken at the conclusion of Slurry Mix Evaporator (SME) operations for this batch and represents the fourth SMECT sample examined from Batch 738. Batch 738 experienced a sludge slurry carryover event, which introduced sludge solids to the SMECT that were particularly evident in the SMECT-5 sample, but less evident in the ‘End of SME Cycle’ SMECT-8 sample.« less

Product/Process (P/P) Models For The Defense Waste Processing Facility (DWPF): Model Ranges And Validation Ranges For Future Processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C.; Edwards, T.

Radioactive high level waste (HLW) at the Savannah River Site (SRS) has successfully been vitrified into borosilicate glass in the Defense Waste Processing Facility (DWPF) since 1996. Vitrification requires stringent product/process (P/P) constraints since the glass cannot be reworked once it is poured into ten foot tall by two foot diameter canisters. A unique “feed forward” statistical process control (SPC) was developed for this control rather than statistical quality control (SQC). In SPC, the feed composition to the DWPF melter is controlled prior to vitrification. In SQC, the glass product would be sampled after it is vitrified. Individual glass property-compositionmore » models form the basis for the “feed forward” SPC. The models transform constraints on the melt and glass properties into constraints on the feed composition going to the melter in order to guarantee, at the 95% confidence level, that the feed will be processable and that the durability of the resulting waste form will be acceptable to a geologic repository.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarrack, A.G.

The purpose of this report is to document fault tree analyses which have been completed for the Defense Waste Processing Facility (DWPF) safety analysis. Logic models for equipment failures and human error combinations that could lead to flammable gas explosions in various process tanks, or failure of critical support systems were developed for internal initiating events and for earthquakes. These fault trees provide frequency estimates for support systems failures and accidents that could lead to radioactive and hazardous chemical releases both on-site and off-site. Top event frequency results from these fault trees will be used in further APET analyses tomore » calculate accident risk associated with DWPF facility operations. This report lists and explains important underlying assumptions, provides references for failure data sources, and briefly describes the fault tree method used. Specific commitments from DWPF to provide new procedural/administrative controls or system design changes are listed in the ''Facility Commitments'' section. The purpose of the ''Assumptions'' section is to clarify the basis for fault tree modeling, and is not necessarily a list of items required to be protected by Technical Safety Requirements (TSRs).« less

Impact of Glycolate Anion on Aqueous Corrosion in DWPF and Downstream Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J.

Glycolic acid is being evaluated as an alternate reductant in the preparation of high level waste for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). During processing, the glycolic acid may not be completely consumed with small quantities of the glycolate anion being carried forward to other high level waste (HLW) facilities. The SRS liquid waste contractor requested an assessment of the impact of the glycolate anion on the corrosion of the materials of construction (MoC) throughout the waste processing system since this impact had not been previously evaluated. A literature review revealed that corrosion datamore » were not available for the MoCs in glycolic-bearing solutions applicable to SRS systems. Data on the material compatibility with only glycolic acid or its derivative products were identified; however, data were limited for solutions containing glycolic acid or the glycolate anion. For the proprietary coating systems applied to the DWPF concrete, glycolic acid was deemed compatible since the coatings were resistant to more aggressive chemistries than glycolic acid. Additionally, similar coating resins showed acceptable resistance to glycolic acid.« less

Impact of Glycolate Anion on Aqueous Corrosion in DWPF and Downstream Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J.

Glycolic acid is being evaluated as an alternate reductant in the preparation of high level waste for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). During processing, the glycolic acid may not be completely consumed with small quantities of the glycolate anion being carried forward to other high level waste (HLW) facilities. The SRS liquid waste contractor requested an assessment of the impact of the glycolate anion on the corrosion of the materials of construction (MoC) throughout the waste processing system since this impact had not been previously evaluated. A literature review revealed that corrosion datamore » were not available for the MoCs in glycolic-bearing solutions applicable to SRS systems. Data on the material compatibility with only glycolic acid or its derivative products were identified; however, data were limited for solutions containing glycolic acid or the glycolate anion. For the proprietary coating systems applied to the DWPF concrete, glycolic acid was deemed compatible since the coatings were resistant to more aggressive chemistries than glycolic acid. Additionally similar coating resins showed acceptable resistance to glycolic acid.« less

TRIPLICATE SODIUM IODIDE GAMMA RAY MONITORS FOR THE SMALL COLUMN ION EXCHANGE PROGRAM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Couture, A.

2011-09-20

This technical report contains recommendations from the Analytical Development (AD) organization of the Savannah River National Laboratory (SRNL) for a system of triplicate Sodium Iodide (NaI) detectors to be used to monitor Cesium-137 ({sup 137}Cs) content of the Decontaminated Salt Solution (DSS) output of the Small Column Ion Exchange (SCIX) process. These detectors need to be gain stabilized with respect to temperature shifts since they will be installed on top of Tank 41 at the Savannah River Site (SRS). This will be accomplished using NaI crystals doped with the alpha-emitting isotope, Americium-241({sup 241}Am). Two energy regions of the detector outputmore » will be monitored using single-channel analyzers (SCAs), the {sup 137}Cs full-energy {gamma}-ray peak and the {sup 241}Am alpha peak. The count rate in the gamma peak region will be proportional to the {sup 137}Cs content in the DSS output. The constant rate of alpha decay in the NaI crystal will be monitored and used as feedback to adjust the high voltage supply to the detector in response to temperature variation. An analysis of theoretical {sup 137}Cs breakthrough curves was used to estimate the gamma activity expected in the DSS output during a single iteration of the process. Count rates arising from the DSS and background sources were predicted using Microshield modeling software. The current plan for shielding the detectors within an enclosure with four-inch thick steel walls should allow the detectors to operate with the sensitivity required to perform these measurements. Calibration, testing, and maintenance requirements for the detector system are outlined as well. The purpose of SCIX is to remove and concentrate high-level radioisotopes from SRS salt waste resulting in two waste streams. The concentrated high-level waste containing {sup 137}Cs will be sent to the Defense Waste Processing Facility (DWPF) for vitrification and the low-level DSS will be sent to the Saltstone Production Facility (SPF) to be incorporated into grout.« less

High Level Waste System Impacts from Small Column Ion Exchange Implementation

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCabe, D. J.; Hamm, L. L.; Aleman, S. E.

2005-08-18

The objective of this task is to identify potential waste streams that could be treated with the Small Column Ion Exchange (SCIX) and perform an initial assessment of the impact of doing so on the High-Level Waste (HLW) system. Design of the SCIX system has been performed as a backup technology for decontamination of High-Level Waste (HLW) at the Savannah River Site (SRS). The SCIX consists of three modules which can be placed in risers inside underground HLW storage tanks. The pump and filter module and the ion exchange module are used to filter and decontaminate the aqueous tank wastesmore » for disposition in Saltstone. The ion exchange module contains Crystalline Silicotitanate (CST in its engineered granular form is referred to as IONSIV{reg_sign} IE-911), and is selective for removal of cesium ions. After the IE-911 is loaded with Cs-137, it is removed and the column is refilled with a fresh batch. The grinder module is used to size-reduce the cesium-loaded IE-911 to make it compatible with the sludge vitrification system in the Defense Waste Processing Facility (DWPF). If installed at the SRS, this SCIX would need to operate within the current constraints of the larger HLW storage, retrieval, treatment, and disposal system. Although the equipment has been physically designed to comply with system requirements, there is also a need to identify which waste streams could be treated, how it could be implemented in the tank farms, and when this system could be incorporated into the HLW flowsheet and planning. This document summarizes a preliminary examination of the tentative HLW retrieval plans, facility schedules, decontamination factor targets, and vitrified waste form compatibility, with recommendations for a more detailed study later. The examination was based upon four batches of salt solution from the currently planned disposition pathway to treatment in the SCIX. Because of differences in capabilities between the SRS baseline and SCIX, these four batches were combined into three batches for a total of about 3.2 million gallons of liquid waste. The chemical and radiological composition of these batches was estimated from the SpaceMan Plus{trademark} model using the same data set and assumptions as the baseline plans.« less

Interim glycol flowsheet reduction/oxidation (redox) model for the Defense Waste Processing Facility (DWPF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C. M.; Williams, M. S.; Zamecnik, J. R.

Control of the REDuction/OXidation (REDOX) state of glasses containing high concentrations of transition metals, such as High Level Waste (HLW) glasses, is critical in order to eliminate processing difficulties caused by overly reduced or overly oxidized melts. Operation of a HLW melter at Fe +2/ΣFe ratios of between 0.09 and 0.33, a range which is not overly oxidizing or overly reducing, helps retain radionuclides in the melt, i.e. long-lived radioactive 99Tc species in the less volatile reduced Tc 4+ state, 104Ru in the melt as reduced Ru +4 state as insoluble RuO 2, and hazardous volatile Cr 6+ in themore » less soluble and less volatile Cr +3 state in the glass. The melter REDOX control balances the oxidants and reductants from the feed and from processing additives such as antifoam. Currently, the Defense Waste Processing Facility (DWPF) is running a formic acid-nitric acid (FN) flowsheet where formic acid is the main reductant and nitric acid is the main oxidant. During decomposition formate and formic acid releases H 2 gas which requires close control of the melter vapor space flammability. A switch to a nitric acid-glycolic acid (GN) flowsheet is desired as the glycolic acid flowsheet releases considerably less H 2 gas upon decomposition. This would greatly simplify DWPF processing. Development of an EE term for glycolic acid in the GN flowsheet is documented in this study.« less

GROUT HOPPER MODELING STUDY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S.

2011-08-30

The Saltstone facility has a grout hopper tank to provide agitator stirring of the Saltstone feed materials. The tank has about 300 gallon capacity to provide a larger working volume for the grout slurry to be held in case of a process upset, and it is equipped with a mechanical agitator, which is intended to keep the grout in motion and agitated so that it won't start to set up. The dry feeds and the salt solution are already mixed in the mixer prior to being transferred to the hopper tank. The hopper modeling study through this work will focusmore » on fluid stirring and agitation, instead of traditional mixing in the literature, in order to keep the tank contents in motion during their residence time so that they will not be upset or solidified prior to transferring the grout to the Saltstone disposal facility. The primary objective of the work is to evaluate the flow performance for mechanical agitators to prevent vortex pull-through for an adequate stirring of the feed materials and to estimate an agitator speed which provides acceptable flow performance with a 45{sup o} pitched four-blade agitator. In addition, the power consumption required for the agitator operation was estimated. The modeling calculations were performed by taking two steps of the Computational Fluid Dynamics (CFD) modeling approach. As a first step, a simple single-stage agitator model with 45{sup o} pitched propeller blades was developed for the initial scoping analysis of the flow pattern behaviors for a range of different operating conditions. Based on the initial phase-1 results, the phase-2 model with a two-stage agitator was developed for the final performance evaluations. A series of sensitivity calculations for different designs of agitators and operating conditions have been performed to investigate the impact of key parameters on the grout hydraulic performance in a 300-gallon hopper tank. For the analysis, viscous shear was modeled by using the Bingham plastic approximation. Steady state analyses with a two-equation turbulence model were performed with the FLUENT{trademark} codes. All analyses were based on three-dimensional results. Recommended operational guidance was developed by using the basic concept that local shear rate profiles and flow patterns can be used as a measure of hydraulic performance and spatial stirring. Flow patterns were estimated by a Lagrangian integration technique along the flow paths from the material feed inlet. The modeling results show that when the two-stage agitator consisting of a 45{sup o} pitched propeller and radial flat-plate blades is run at 140 rpm speed with 28 in diameter, the agitator provides an adequate stirring of the feed materials for a wide range of yield stresses (1 to 21 Pa) and the vortex system is shed into the remote region of the tank boundary by the blade passage in an efficient way. The results of this modeling study were used to develop the design guidelines for the agitator stirring and dispersion of the Saltstone feed materials in a hopper tank.« less

Secondary Waste Cementitious Waste Form Data Package for the Integrated Disposal Facility Performance Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cantrell, Kirk J.; Westsik, Joseph H.; Serne, R Jeffrey

A review of the most up-to-date and relevant data currently available was conducted to develop a set of recommended values for use in the Integrated Disposal Facility (IDF) performance assessment (PA) to model contaminant release from a cementitious waste form for aqueous wastes treated at the Hanford Effluent Treatment Facility (ETF). This data package relies primarily upon recent data collected on Cast Stone formulations fabricated with simulants of low-activity waste (LAW) and liquid secondary wastes expected to be produced at Hanford. These data were supplemented, when necessary, with data developed for saltstone (a similar grout waste form used at themore » Savannah River Site). Work is currently underway to collect data on cementitious waste forms that are similar to Cast Stone and saltstone but are tailored to the characteristics of ETF-treated liquid secondary wastes. Recommended values for key parameters to conduct PA modeling of contaminant release from ETF-treated liquid waste are provided.« less

Inhibiting localized corrosion during storage of dilute SRP wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oblath, S.B.; Congdon, J.W.

1986-01-01

High-level radioactive waste will be incorporated in borosilicate glass in the Defense Waste Processing Facility (DWPF) at the Savannah River Plant (SRP). As part of this process, large volumes of inorganic salt wastes will be decontaminated for disposal as low-level waste. The principal contaminants, /sup 137/Cs and /sup 90/Sr, are removed by treatment with sodium tetraphenylborate and sodium titanate. The resulting solids will be slurried with a dilute salt solution and stored in existing carbon steel tanks for several years prior to processing and disposal. Initial tests indicated a tendency for localized corrosion of the tanks. An investigation, using nonradioactivemore » simulants for the expected solution compositions, identified inhibitors which would protect the steel. Changes in solution compositions over time, due to radiolytic effects, were also accounted for by the simulants. Six inhibitors were identified which would protect the steel tanks. The effects these inhibitors would have on later processing steps in the DWPF were then evaluated. After this process, only sodium nitrite remained as an inhibitor that was both effective and compatible with the DWPF. The use of this inhibitor has been demonstrated on a real waste slurry.« less

ISOLOK VALVE ACCEPTANCE TESTING FOR DWPF SME SAMPLING PROCESS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.; Hera, K.; Coleman, C.

2011-12-05

Evaluation of the Defense Waste Processing Facility (DWPF) Chemical Process Cell (CPC) cycle time identified several opportunities to improve the CPC processing time. Of the opportunities, a focus area related to optimizing the equipment and efficiency of the sample turnaround time for DWPF Analytical Laboratory was identified. The Mechanical Systems & Custom Equipment Development (MS&CED) Section of the Savannah River National Laboratory (SRNL) evaluated the possibility of using an Isolok{reg_sign} sampling valve as an alternative to the Hydragard{reg_sign} valve for taking process samples. Previous viability testing was conducted with favorable results using the Isolok sampler and reported in SRNL-STI-2010-00749 (1).more » This task has the potential to improve operability, reduce maintenance time and decrease CPC cycle time. This report summarizes the results from acceptance testing which was requested in Task Technical Request (TTR) HLW-DWPF-TTR-2010-0036 (2) and which was conducted as outlined in Task Technical and Quality Assurance Plan (TTQAP) SRNL-RP-2011-00145 (3). The Isolok to be tested is the same model which was tested, qualified, and installed in the Sludge Receipt Adjustment Tank (SRAT) sample system. RW-0333P QA requirements apply to this task. This task was to qualify the Isolok sampler for use in the DWPF Slurry Mix Evaporator (SME) sampling process. The Hydragard, which is the current baseline sampling method, was used for comparison to the Isolok sampling data. The Isolok sampler is an air powered grab sampler used to 'pull' a sample volume from a process line. The operation of the sampler is shown in Figure 1. The image on the left shows the Isolok's spool extended into the process line and the image on the right shows the sampler retracted and then dispensing the liquid into the sampling container. To determine tank homogeneity, a Coliwasa sampler was used to grab samples at a high and low location within the mixing tank. Data from the two locations were compared to determine if the contents of the tank were well mixed. The Coliwasa sampler is a tube with a stopper at the bottom and is designed to obtain grab samples from specific locations within the drum contents. A position paper (4) was issued to address the prototypic flow loop issues and simulant selections. A statistically designed plan (5) was issued to address the total number of samples each sampler needed to pull, to provide the random order in which samples were pulled and to group samples for elemental analysis. The TTR required that the Isolok sampler perform as well as the Hydragard sampler during these tests to ensure the acceptability of the Isolok sampler for use in the DWPF sampling cells. Procedure No.L9.4-5015 was used to document the sample parameters and process steps. Completed procedures are located in R&D Engineering job folder 23269.« less

SLUDGE BATCH 6/TANK 40 SIMULANT CHEMICAL PROCESS CELL SIMULATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopman, David

2010-04-28

Phase III simulant flowsheet testing was completed using the latest composition estimates for SB6/Tank 40 feed to DWPF. The goals of the testing were to determine reasonable operating conditions and assumptions for the startup of SB6 processing in the DWPF. Testing covered the region from 102-159% of the current DWPF stoichiometric acid equation. Nitrite ion concentration was reduced to 90 mg/kg in the SRAT product of the lowest acid run. The 159% acid run reached 60% of the DWPF Sludge Receipt and Adjustment Tank (SRAT) limit of 0.65 lb H2/hr, and then sporadically exceeded the DWPF Slurry Mix Evaporator (SME)more » limit of 0.223 lb H2/hr. Hydrogen generation rates peaked at 112% of the SME limit, but higher than targeted wt% total solids levels may have been partially responsible for rates seen. A stoichiometric factor of 120% met both objectives. A processing window for SB6 exists from 102% to something close to 159% based on the simulant results. An initial recommendation for SB6 processing is at 115-120% of the current DWPF stoichiometric acid equation. The addition of simulated Actinide Removal Process (ARP) and Modular Caustic Side Solvent Extraction Unit (MCU) streams to the SRAT cycle had no apparent impact on the preferred stoichiometric factor. Hydrogen generation occurred continuously after acid addition in three of the four tests. The three runs at 120%, 118.4% with ARP/MCU, and 159% stoichiometry were all still producing around 0.1 lb hydrogen/hr at DWPF scale after 36 hours of boiling in the SRAT. The 120% acid run reached 23% of the SRAT limit and 37% of the SME limit. Conversely, nitrous oxide generation was subdued compared to previous sludge batches, staying below 29 lb/hr in all four tests or about a fourth as much as in comparable SB4 testing. Two processing issues, identified during SB6 Phase II flowsheet testing and qualification simulant testing, were monitored during Phase III. Mercury material balance closure was impacted by acid stoichiometry, and significant mercury was not accounted for in the highest acid run. Coalescence of elemental mercury droplets in the mercury water wash tank (MWWT) appeared to degrade with increasing stoichiometry. Observations were made of mercury scale formation in the SRAT condenser and MWWT. A tacky mercury amalgam with Rh, Pd, and Cu, plus some Ru and Ca formed on the impeller at 159% acid. It contained a significant fraction of the available Pd, Cu, and Rh as well as about 25% of the total mercury charged. Free (elemental) mercury was found in all of the SME products. Ammonia scrubbers were used during the tests to capture off-gas ammonia for material balance purposes. Significant ammonium ion formation was again observed during the SRAT cycle, and ammonia gas entered the off-gas as the pH rose during boiling. Ammonium ion production was lower than in the SB6 Phase II and the qualification simulant testing. Similar ammonium ion formation was seen in the ARP/MCU simulation as in the 120% flowsheet run. A slightly higher pH caused most of the ammonium to vaporize and collect in the ammonia scrubber reflux solution. Two periods of foaminess were noted. Neither required additional antifoam to control the foam growth. A steady foam layer formed during reflux in the 120% acid run. It was about an inch thick, but was 2-3 times more volume of bubbles than is typically seen during reflux. A similar foam layer also was seen during caustic boiling of the simulant during the ARP addition. While frequently seen with the radioactive sludge, foaminess during caustic boiling with simulants has been relatively rare. Two further flowsheet tests were performed and will be documented separately. One test was to evaluate the impact of process conditions that match current DWPF operation (lower rates). The second test was to evaluate the impact of SRAT/SME processing on the rheology of a modified Phase III simulant that had been made five times more viscous using ultrasonication.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D.; Edwards, T.

High-level waste (HLW) throughput (i.e., the amount of waste processed per unit of time) is primarily a function of two critical parameters: waste loading (WL) and melt rate. For the Defense Waste Processing Facility (DWPF), increasing HLW throughput would significantly reduce the overall mission life cycle costs for the Department of Energy (DOE). Significant increases in waste throughput have been achieved at DWPF since initial radioactive operations began in 1996. Key technical and operational initiatives that supported increased waste throughput included improvements in facility attainment, the Chemical Processing Cell (CPC) flowsheet, process control models and frit formulations. As a resultmore » of these key initiatives, DWPF increased WLs from a nominal 28% for Sludge Batch 2 (SB2) to {approx}34 to 38% for SB3 through SB6 while maintaining or slightly improving canister fill times. Although considerable improvements in waste throughput have been obtained, future contractual waste loading targets are nominally 40%, while canister production rates are also expected to increase (to a rate of 325 to 400 canisters per year). Although implementation of bubblers have made a positive impact on increasing melt rate for recent sludge batches targeting WLs in the mid30s, higher WLs will ultimately make the feeds to DWPF more challenging to process. Savannah River Remediation (SRR) recently requested the Savannah River National Laboratory (SRNL) to perform a paper study assessment using future sludge projections to evaluate whether the current Process Composition Control System (PCCS) algorithms would provide projected operating windows to allow future contractual WL targets to be met. More specifically, the objective of this study was to evaluate future sludge batch projections (based on Revision 16 of the HLW Systems Plan) with respect to projected operating windows using current PCCS models and associated constraints. Based on the assessments, the waste loading interval over which a glass system (i.e., a projected sludge composition with a candidate frit) is predicted to be acceptable can be defined (i.e., the projected operating window) which will provide insight into the ability to meet future contractual WL obligations. In this study, future contractual WL obligations are assumed to be 40%, which is the goal after all flowsheet enhancements have been implemented to support DWPF operations. For a system to be considered acceptable, candidate frits must be identified that provide access to at least 40% WL while accounting for potential variation in the sludge resulting from differences in batch-to-batch transfers into the Sludge Receipt and Adjustment Tank (SRAT) and/or analytical uncertainties. In more general terms, this study will assess whether or not the current glass formulation strategy (based on the use of the Nominal and Variation Stage assessments) and current PCCS models will allow access to compositional regions required to targeted higher WLs for future operations. Some of the key questions to be considered in this study include: (1) If higher WLs are attainable with current process control models, are the models valid in these compositional regions? If the higher WL glass regions are outside current model development or validation ranges, is there existing data that could be used to demonstrate model applicability (or lack thereof)? If not, experimental data may be required to revise current models or serve as validation data with the existing models. (2) Are there compositional trends in frit space that are required by the PCCS models to obtain access to these higher WLs? If so, are there potential issues with the compositions of the associated frits (e.g., limitations on the B{sub 2}O{sub 3} and/or Li{sub 2}O concentrations) as they are compared to model development/validation ranges or to the term 'borosilicate' glass? If limitations on the frit compositional range are realized, what is the impact of these restrictions on other glass properties such as the ability to suppress nepheline formation or influence melt rate? The model based assessments being performed make the assumption that the process control models are applicable over the glass compositional regions being evaluated. Although the glass compositional region of interest is ultimately defined by the specific frit, sludge, and WL interval used, there is no prescreening of these compositional regions with respect to the model development or validation ranges which is consistent with current DWPF operations.« less

Defense waste processing facility (DWPF) liquids model: revisions for processing higher TIO 2 containing glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C. M.; Edwards, T. B.; Trivelpiece, C. L.

Radioactive high level waste (HLW) at the Savannah River Site (SRS) has successfully been vitrified into borosilicate glass in the Defense Waste Processing Facility (DWPF) since 1996. Vitrification requires stringent product/process (P/P) constraints since the glass cannot be reworked once it is poured into ten foot tall by two foot diameter canisters. A unique “feed forward” statistical process control (SPC) was developed for this control rather than statistical quality control (SQC). In SPC, the feed composition to the DWPF melter is controlled prior to vitrification. In SQC, the glass product would be sampled after it is vitrified. Individual glass property-compositionmore » models form the basis for the “feed forward” SPC. The models transform constraints on the melt and glass properties into constraints on the feed composition going to the melter in order to guarantee, at the 95% confidence level, that the feed will be processable and that the durability of the resulting waste form will be acceptable to a geologic repository. This report documents the development of revised TiO 2, Na 2O, Li 2O and Fe 2O 3 coefficients in the SWPF liquidus model and revised coefficients (a, b, c, and d).« less

Nucleation and crystal growth behavior of nepheline in simulated high-level waste glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, K.; Amoroso, J.; Mcclane, D.

The Savannah River National Laboratory (SRNL) has been tasked with supporting glass formulation development and process control strategies in key technical areas, relevant to the Department of Energy’s Office of River Protection (DOE-ORP) and related to high-level waste (HLW) vitrification at the Waste Treatment and Immobilization Plant (WTP). Of specific interest is the development of predictive models for crystallization of nepheline (NaAlSiO4) in HLW glasses formulated at high alumina concentrations. This report summarizes recent progress by researchers at SRNL towards developing a predicative tool for quantifying nepheline crystallization in HLW glass canisters using laboratory experiments. In this work, differential scanningmore » calorimetry (DSC) was used to obtain the temperature regions over which nucleation and growth of nepheline occur in three simulated HLW glasses - two glasses representative of WTP projections and one glass representative of the Defense Waste Processing Facility (DWPF) product. The DWPF glass, which has been studied previously, was chosen as a reference composition and for comparison purposes. Complementary quantitative X-ray diffraction (XRD) and optical microscopy confirmed the validity of the methodology to determine nucleation and growth behavior as a function of temperature. The nepheline crystallization growth region was determined to generally extend from ~ 500 to >850 °C, with the maximum growth rates occurring between 600 and 700 °C. For select WTP glass compositions (high Al2O3 and B2O3), the nucleation range extended from ~ 450 to 600 °C, with the maximum nucleation rates occurring at ~ 530 °C. For the DWPF glass composition, the nucleation range extended from ~ 450 to 750 °C with the maximum nucleation rate occurring at ~ 640 °C. The nepheline growth at the peak temperature, as determined by XRD, was between 35 - 75 wt.% /hour. A maximum nepheline growth rate of ~ 0.1 mm/hour at 700 °C was measured for the DWPF composition using optical microscopy. This research establishes a viable alternative to more traditional techniques for evaluating nepheline crystallization in large numbers of glasses, which are prohibitively time consuming or otherwise impractical. The ultimate objective is to combine the nucleation and growth information obtained from DSC, like that presented in this report, with computer simulations of glass cooling within the canister to accurately predict nepheline crystallization in HLW during processing through WTP.« less

NUMERICAL FLOW AND TRANSPORT SIMULATIONS SUPPORTING THE SALTSTONE FACILITY PERFORMANCE ASSESSMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flach, G.

2009-02-28

The Saltstone Disposal Facility Performance Assessment (PA) is being revised to incorporate requirements of Section 3116 of the Ronald W. Reagan National Defense Authorization Act for Fiscal Year 2005 (NDAA), and updated data and understanding of vault performance since the 1992 PA (Cook and Fowler 1992) and related Special Analyses. A hybrid approach was chosen for modeling contaminant transport from vaults and future disposal cells to exposure points. A higher resolution, largely deterministic, analysis is performed on a best-estimate Base Case scenario using the PORFLOW numerical analysis code. a few additional sensitivity cases are simulated to examine alternative scenarios andmore » parameter settings. Stochastic analysis is performed on a simpler representation of the SDF system using the GoldSim code to estimate uncertainty and sensitivity about the Base Case. This report describes development of PORFLOW models supporting the SDF PA, and presents sample results to illustrate model behaviors and define impacts relative to key facility performance objectives. The SDF PA document, when issued, should be consulted for a comprehensive presentation of results.« less

The Impact Of The MCU Life Extension Solvent On Sludge Batch 8 Projected Operating Windows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D. K.; Edwards, T. B.

2013-06-26

As a part of the Actinide Removal Process (ARP)/Modular Caustic Side Solvent Extraction Unit (MCU) Life Extension Project, a next generation solvent (NGS) and a new strip acid will be deployed. The strip acid will be changed from dilute nitric acid to dilute boric acid (0.01 M). Because of these changes, experimental testing or evaluations with the next generation solvent are required to determine the impact of these changes (if any) to Chemical Process Cell (CPC) activities, glass formulation strategies, and melter operations at the Defense Waste Processing Facility (DWPF). The introduction of the dilute (0.01 M) boric acid streammore » into the DWPF flowsheet has a potential impact on glass formulation and frit development efforts since B203 is a major oxide in frits developed for DWPF. Prior knowledge of this stream can be accounted for during frit development efforts but that was not the case for Sludge Batch 8 (SB8). Frit 803 has already been recommended and procured for SB8 processing; altering the frit to account for the incoming boron from the strip effluent (SE) is not an option for SB8. Therefore, the operational robustness of Frit 803 to the introduction of SE including its compositional tolerances (i.e., up to 0.0125M boric acid) is of interest and was the focus of this study. The primary question to be addressed in the current study was: What is the impact (if any) on the projected operating windows for the Frit 803 - SB8 flowsheet to additions of B203 from the SE in the Sludge Receipt and Adjustment Tank (SRAT)? More specifically, will Frit 803 be robust to the potential compositional changes occurring in the SRAT due to sludge variation, varying additions of ARP and/or the introduction of SE by providing access to waste loadings (WLs) of interest to DWPF? The Measurement Acceptability Region (MAR) results indicate there is very little, if any, impact on the projected operating windows for the Frit 803 - SB8 system regardless of the presence or absence of ARP and SE (up to 2 wt% B203 contained in the SRAT and up to 2000 gallons of ARP). It should be noted that 0.95 wt% B203 is the nominal projected concentration in the SRAT based on a 0.0125M boric acid flowsheet with 70,000 liters of SE being added to the SRAT.« less

Results of Hg speciation testing on DWPF SMECT-4, SMECT-6, and RCT-2 samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.

2016-02-04

The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team.i,ii The fifteenth shipment of samples was designated to include Defense Waste Processing Facility (DWPF) Slurry Mix Evaporator Condensate Tank (SMECT) samples from Sludge Receipt and Adjustment Tank (SRAT) Batch 738 and a Recycle Condensate Tank (RCT) sample from SRAT Batch 736. The DWPF sample designations for the three samples analyzed are provided in Table 1. The Batch 738 ‘Baseline’ SMECT sample was taken priormore » to Precipitate Reactor Feed Tank (PRFT) addition and concentration and therefore, precedes the SMECT-5 sample reported previously. iii The Batch 738 ‘End of SRAT Cycle’ SMECT sample was taken at the conclusion of SRAT operations for this batch (PRFT addition/concentration, acid additions, initial concentration, MCU addition, and steam stripping). Batch 738 experienced a sludge slurry carryover event, which introduced sludge solids to the SMECT that were particularly evident in the SMECT-5 sample, but less evident in the ‘End of SRAT Cycle’ SMECT-6 sample. The Batch 736 ‘After SME’ RCT sample was taken after completion of SMECT transfers at the end of the SME cycle.« less

In vitro dissolution of strontium titanate to estimate clearance rates in human lungs

NASA Astrophysics Data System (ADS)

Anderson, Jeri Lynn

At the In-Tank Precipitation facility (ITP) of the Savannah River Site, strontium and other radionuclides are removed from high-level radioactive waste and sent to the Defense Waste Processing Facility (DWPF). Strontium removal is accomplished by ion-exchange using monosodium titanate slurry which creates a form of strontium titanate with unknown solubility characteristics. In the case of accidental inhalation of a compound containing radioactive strontium, the ICRP, in Publication 66, recommends using default values for rates of absorption into body fluids at the lungs in the absence of reliable human or animal data. The default value depends on whether the absorption is considered to be fast, moderate, or slow (Type F, M, or S). Current dose assessment for an individual upon inadvertent exposure to airborne radioactive strontium assumes that all strontium compounds are Type F (soluble) or Type S (insoluble). Pure high-fired strontium titanate (SrTiOsb3) is considered Type S. The purpose of this project was to determine the solubility of strontium titanate in the form created at the ITP facility. An in vitro dissolution study was done with a precipitate simulant and with several types of strontium titanate and the results were compared. An in vivo study was also performed with high-fired SrTiOsb3 in rats. The data from both studies were used independently to assign the compounds to absorption type based on criteria specified in ICRP 71. Results of the in vitro studies showed that the DWPF simulant should be assigned to Type M and the strontium titanate should be assigned to Type S. It is possible the difference in the DWPF simulant is due to the other chemicals present. Results of the in vivo study verified that SrTiOsb3 should be assigned to Type S. Lung clearance data of SrTiOsb3 from rats showed that 85% cleared within the first 24 hours and the remaining 15% with a half-time of 130 days. The initial rapid clearance is attributed to deposition in airways as compared to the alveolar region.

SLUDGE BATCH 7B QUALIFICATION ACTIVITIES WITH SRS TANK FARM SLUDGE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J.; Click, D.; Lambert, D.

2011-11-16

Waste Solidification Engineering (WSE) has requested that characterization and a radioactive demonstration of the next batch of sludge slurry - Sludge Batch 7b (SB7b) - be completed in the Shielded Cells Facility of the Savannah River National Laboratory (SRNL) via a Technical Task Request (TTR). This characterization and demonstration, or sludge batch qualification process, is required prior to transfer of the sludge from Tank 51 to the Defense Waste Processing Facility (DWPF) feed tank (Tank 40). The current WSE practice is to prepare sludge batches in Tank 51 by transferring sludge from other tanks. Discharges of nuclear materials from Hmore » Canyon are often added to Tank 51 during sludge batch preparation. The sludge is washed and transferred to Tank 40, the current DWPF feed tank. Prior to transfer of Tank 51 to Tank 40, SRNL typically simulates the Tank Farm and DWPF processes with a Tank 51 sample (referred to as the qualification sample). With the tight schedule constraints for SB7b and the potential need for caustic addition to allow for an acceptable glass processing window, the qualification for SB7b was approached differently than past batches. For SB7b, SRNL prepared a Tank 51 and a Tank 40 sample for qualification. SRNL did not receive the qualification sample from Tank 51 nor did it simulate all of the Tank Farm washing and decanting operations. Instead, SRNL prepared a Tank 51 SB7b sample from samples of Tank 7 and Tank 51, along with a wash solution to adjust the supernatant composition to the final SB7b Tank 51 Tank Farm projections. SRNL then prepared a sample to represent SB7b in Tank 40 by combining portions of the SRNL-prepared Tank 51 SB7b sample and a Tank 40 Sludge Batch 7a (SB7a) sample. The blended sample was 71% Tank 40 (SB7a) and 29% Tank 7/Tank 51 on an insoluble solids basis. This sample is referred to as the SB7b Qualification Sample. The blend represented the highest projected Tank 40 heel (as of May 25, 2011), and thus, the highest projected noble metals content for SB7b. Characterization was performed on the Tank 51 SB7b samples and SRNL performed DWPF simulations using the Tank 40 SB7b material. This report documents: (1) The preparation and characterization of the Tank 51 SB7b and Tank 40 SB7b samples. (2) The performance of a DWPF Chemical Process Cell (CPC) simulation using the SB7b Tank 40 sample. The simulation included a Sludge Receipt and Adjustment Tank (SRAT) cycle, where acid was added to the sludge to destroy nitrite and reduce mercury, and a Slurry Mix Evaporator (SME) cycle, where glass frit was added to the sludge in preparation for vitrification. The SME cycle also included replication of five canister decontamination additions and concentrations. Processing parameters were based on work with a nonradioactive simulant. (3) Vitrification of a portion of the SME product and characterization and durability testing (as measured by the Product Consistency Test (PCT)) of the resulting glass. (4) Rheology measurements of the SRAT receipt, SRAT product, and SME product. This program was controlled by a Task Technical and Quality Assurance Plan (TTQAP), and analyses were guided by an Analytical Study Plan. This work is Technical Baseline Research and Development (R&D) for the DWPF. It should be noted that much of the data in this document has been published in interoffice memoranda. The intent of this technical report is bring all of the SB7b related data together in a single permanent record and to discuss the overall aspects of SB7b processing.« less

YIELD STRESS REDUCTION OF DWPF MELTER FEED SLURRIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M; Michael02 Smith, M

2006-12-28

The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies High Level Waste for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. The HLW consists of insoluble metal hydroxides (primarily iron, aluminum, magnesium, manganese, and uranium) and soluble sodium salts (carbonate, hydroxide, nitrite, nitrate, sulfate). The pretreatment process acidifies the sludge with nitric and formic acids, adds the glass formers as glass frit, then concentrates the resulting slurry to approximately 50 weight percent (wt%) total solids. This slurry is fed to the joule-heated melter where the remaining water is evaporated followedmore » by calcination of the solids and conversion to glass. The Savannah River National Laboratory (SRNL) is currently assisting DWPF efforts to increase throughput of the melter. As part of this effort, SRNL has investigated methods to increase the solids content of the melter feed to reduce the heat load required to complete the evaporation of water and allow more of the energy available to calcine and vitrify the waste. The process equipment in the facility is fixed and cannot process materials with high yield stresses, therefore increasing the solids content will require that the yield stress of the melter feed slurries be reduced. Changing the glass former added during pretreatment from an irregularly shaped glass frit to nearly spherical beads was evaluated. The evaluation required a systems approach which included evaluations of the effectiveness of beads in reducing the melter feed yield stress as well as evaluations of the processing impacts of changing the frit morphology. Processing impacts of beads include changing the settling rate of the glass former (which effects mixing and sampling of the melter feed slurry and the frit addition equipment) as well as impacts on the melt behavior due to decreased surface area of the beads versus frit. Beads were produced from the DWPF process frit by fire polishing. The frit was allowed to free fall through a flame, then quenched with a water spray. Approximately 90% of the frit was converted to beads by this process, as shown in Figure 1. Borosilicate beads of various diameters were also procured for initial testing.« less

Defense Waste Processing Facility Process Enhancements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bricker, Jonathan

2010-11-01

Jonathan Bricker provides an overview of process enhancements currently being done at the Defense Waste Processing Facility (DWPF) at SRS. Some of these enhancements include: melter bubblers; reduction in water use, and alternate reductant.

Impact of glycolate anion on aqueous corrosion in DWPF and downstream facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J. I.

2015-12-15

Glycolic acid is being evaluated as an alternate reductant in the preparation of high level waste for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). During processing, the glycolic acid may not be completely consumed with small quantities of the glycolate anion being carried forward to other high level waste (HLW) facilities. The impact of the glycolate anion on the corrosion of the materials of construction (MoC) throughout the waste processing system has not been previously evaluated. A literature review had revealed that corrosion data were not available for the MoCs in glycolic-bearing solutions applicable tomore » SRS systems. Data on the material compatibility with only glycolic acid or its derivative products were identified; however, data were limited for solutions containing glycolic acid or the glycolate anion.« less

Characterization Of The As-Received Sludge Batch 9 Qualification Sample (Htf-51-15-81)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J.

Savannah River National Laboratory (SRNL) personnel have been requested to qualify the next sludge batch (Sludge Batch 9 – SB9) for processing at the Defense Waste Processing Facility (DWPF). To accomplish this task, Savannah River Remediation (SRR) has sent SRNL a 3-L slurried sample of Tank 51H (HTF-51-15-81) to be characterized, washed, and then used in a lab-scale demonstration of the DWPF flowsheet (potentially after combining with Tank 40H sludge). This report documents the first steps of the qualification process – characterization of the as-received Tank 51H qualification sample. These results will be used to support a reprojection of SB9more » by SRR from which final Tank 51H washing, frit development, and Chemical Processing Cell (CPC) activities will be based.« less

Sludge batch 9 simulant runs using the nitric-glycolic acid flowsheet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D. P.; Williams, M. S.; Brandenburg, C. H.

Testing was completed to develop a Sludge Batch 9 (SB9) nitric-glycolic acid chemical process flowsheet for the Defense Waste Processing Facility’s (DWPF) Chemical Process Cell (CPC). CPC simulations were completed using SB9 sludge simulant, Strip Effluent Feed Tank (SEFT) simulant and Precipitate Reactor Feed Tank (PRFT) simulant. Ten sludge-only Sludge Receipt and Adjustment Tank (SRAT) cycles and four SRAT/Slurry Mix Evaporator (SME) cycles, and one actual SB9 sludge (SRAT/SME cycle) were completed. As has been demonstrated in over 100 simulations, the replacement of formic acid with glycolic acid virtually eliminates the CPC’s largest flammability hazards, hydrogen and ammonia. Recommended processingmore » conditions are summarized in section 3.5.1. Testing demonstrated that the interim chemistry and Reduction/Oxidation (REDOX) equations are sufficient to predict the composition of DWPF SRAT product and SME product. Additional reports will finalize the chemistry and REDOX equations. Additional testing developed an antifoam strategy to minimize the hexamethyldisiloxane (HMDSO) peak at boiling, while controlling foam based on testing with simulant and actual waste. Implementation of the nitric-glycolic acid flowsheet in DWPF is recommended. This flowsheet not only eliminates the hydrogen and ammonia hazards but will lead to shorter processing times, higher elemental mercury recovery, and more concentrated SRAT and SME products. The steady pH profile is expected to provide flexibility in processing the high volume of strip effluent expected once the Salt Waste Processing Facility starts up.« less

PRELIMINARY EVALUATION OF DWPF IMPACTS OF BORIC ACID USE IN CESIUM STRIP FOR SWPF AND MCU

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M.

2010-09-28

A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system includes the option to replace the current dilute nitric acid strip solution with boric acid. To support this effort, the impact of using 0.01M, 0.1M, 0.25M and 0.5M boric acid in place of 0.001M nitric acid was evaluated for impacts on the DWPF facility. The evaluation only covered the impacts of boric acid in the strip effluent and does not address the other changes in solvents (i.e., the new extractant, called MaxCalix,more » or the new suppressor, guanidine). Boric acid additions may lead to increased hydrogen generation during the SRAT and SME cycles as well as change the rheological properties of the feed. The boron in the strip effluent will impact glass composition and could require each SME batch to be trimmed with boric acid to account for any changes in the boron from strip effluent additions. Addition of boron with the strip effluent will require changes in the frit composition and could lead to changes in melt behavior. The severity of the impacts from the boric acid additions is dependent on the amount of boric acid added by the strip effluent. The use of 0.1M or higher concentrations of boric acid in the strip effluent was found to significantly impact DWPF operations while the impact of 0.01M boric acid is expected to be relatively minor. Experimental testing is required to resolve the issues identified during the preliminary evaluation. The issues to be addressed by the testing are: (1) Impact on SRAT acid addition and hydrogen generation; (2) Impact on melter feed rheology; (3) Impact on glass composition control; (4) Impact on frit production; and (5) Impact on melter offgas. A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system includes the option to replace the current dilute nitric acid strip solution with boric acid. To support this effort, the impact of using 0.01M, 0.1M, 0.25M and 0.5M boric acid in place of 0.001M nitric acid was evaluated for impacts on the DWPF facility. The evaluation only covered the impacts of boric acid in the strip effluent and does not address the other changes in solvents (i.e., the new extractant, called MaxCalix, or the new suppressor, guanidine). Experimental testing with the improved solvent is required to determine the impact of any changes in the entrained solvent on DWPF processing.« less

Solidification of Savannah River plant high level waste

NASA Astrophysics Data System (ADS)

Maher, R.; Shafranek, L. F.; Kelley, J. A.; Zeyfang, R. W.

1981-11-01

Authorization for construction of the Defense Waste Processing Facility (DWPF) is expected in FY-83. The optimum time for stage 2 authorization is about three years later. Detailed design and construction will require approximately five years for stage 1, with stage 2 construction completed about two to three years later. Production of canisters of waste glass would begin in 1988, and the existing backlog of high level waste sludge stored at SRP would be worked off by about the year 2000. Stage 2 operation could begin in 1990. The technology and engineering are ready for construction and eventual operation of the DWPF for immobilizing high level radioactive waste at Savannah River Plant (SRP). Proceeding with this project will provide the public, and the leadership of this country, with a crucial demonstration that a major quanitity of existing high level nuclear wastes can be safely and permanently immobilized.

Verification Of The Defense Waste Processing Facility's (DWPF) Process Digestion Methods For The Sludge Batch 8 Qualification Sample

DOE Office of Scientific and Technical Information (OSTI.GOV)

Click, D. R.; Edwards, T. B.; Wiedenman, B. J.

2013-03-18

This report contains the results and comparison of data generated from inductively coupled plasma – atomic emission spectroscopy (ICP-AES) analysis of Aqua Regia (AR), Sodium Peroxide/Sodium Hydroxide Fusion Dissolution (PF) and Cold Chem (CC) method digestions and Cold Vapor Atomic Absorption analysis of Hg digestions from the DWPF Hg digestion method of Sludge Batch 8 (SB8) Sludge Receipt and Adjustment Tank (SRAT) Receipt and SB8 SRAT Product samples. The SB8 SRAT Receipt and SB8 SRAT Product samples were prepared in the SRNL Shielded Cells, and the SRAT Receipt material is representative of the sludge that constitutes the SB8 Batch ormore » qualification composition. This is the sludge in Tank 51 that is to be transferred into Tank 40, which will contain the heel of Sludge Batch 7b (SB7b), to form the SB8 Blend composition.« less

Antifoam Degradation Products in Off Gas and Condensate of Sludge Batch 9 Simulant Nitric-Formic Flowsheet Testing for the Defense Waste Processing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, T.

Ten chemical processing cell (CPC) experiments were performed using simulant to evaluate Sludge Batch 9 for sludge-only and coupled processing using the nitric-formic flowsheet in the Defense Waste Processing Facility (DWPF). Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) cycles were performed on eight of the ten. The other two were SRAT cycles only. Samples of the condensate, sludge, and off gas were taken to monitor the chemistry of the CPC experiments. The Savannah River National Laboratory (SRNL) has previously shown antifoam decomposes to form flammable organic products, (hexamethyldisiloxane (HMDSO), trimethylsilanol (TMS), and propanal), that are presentmore » in the vapor phase and condensate of the CPC vessels. To minimize antifoam degradation product formation, a new antifoam addition strategy was implemented at SRNL and DWPF to add antifoam undiluted.« less

Analysis Of Condensate Samples In Support Of The Antifoam Degradation Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hay, M.; Martino, C.

2016-01-12

The degradation of Antifoam 747 to form flammable decomposition products has resulted in declaration of a Potential Inadequacy in the Safety Analysis (PISA) for the Defense Waste Processing Facility (DWPF). Savannah River National Laboratory (SRNL) testing with simulants showed that hexamethyldisiloxane (HMDSO), trimethylsilanol (TMS), and 1-propanal are formed in the offgas from the decomposition of the antifoam. A total of ten DWPF condensate samples from Batch 735 and 736 were analyzed by SRNL for three degradation products and additional analytes. All of the samples were analyzed to determine the concentrations of HMDSO, TMS, and propanal. The results of the organicmore » analysis found concentrations for propanal and HMDSO near or below the detection limits for the analysis. The TMS concentrations ranged from below detection to 11 mg/L. The samples from Batch 736 were also analyzed for formate and oxalate anions, total organic carbon, and aluminum, iron, manganese, and silicon. Most of the samples contained low levels of formate and therefore low levels of organic carbon. These two values for each sample show reasonable agreement in most cases. Low levels of all the metals (Al, Fe, Mn, and Si) were present in most of the samples.« less

ANALYSIS OF CONDENSATE SAMPLES IN SUPPORT OF THE ANTIFOAM DEGRADATION STUDY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hay, M.; Martino, C.

2016-02-29

The degradation of Antifoam 747 to form flammable decomposition products has resulted in declaration of a Potential Inadequacy in the Safety Analysis (PISA) for the Defense Waste Processing Facility (DWPF). Savannah River National Laboratory (SRNL) testing with simulants showed that hexamethyldisiloxane (HMDSO), trimethylsilanol (TMS), and 1-propanal are formed in the offgas from the decomposition of the antifoam. A total of ten DWPF condensate samples from Batch 735 and 736 were analyzed by SRNL for three degradation products and additional analytes. All of the samples were analyzed to determine the concentrations of HMDSO, TMS, and propanal. The results of the organicmore » analysis found concentrations for propanal and HMDSO near or below the detection limits for the analysis. The TMS concentrations ranged from below detection to 11 mg/L. The samples from Batch 736 were also analyzed for formate and oxalate anions, total organic carbon, and aluminum, iron, manganese, and silicon. Most of the samples contained low levels of formate and therefore low levels of organic carbon. These two values for each sample show reasonable agreement in most cases. Low levels of all the metals (Al, Fe, Mn, and Si) were present in most of the samples.« less

DEVELOPMENT OF REMOTE HANFORD CONNECTOR GASKET REPLACEMENT TOOLING FOR DWPF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krementz, D.; Coughlin, Jeffrey

2009-05-05

The Defense Waste Processing Facility (DWPF) requested the Savannah River National Laboratory (SRNL) to develop tooling and equipment to remotely replace gaskets in mechanical Hanford connectors to reduce personnel radiation exposure as compared to the current hands-on method. It is also expected that radiation levels will continually increase with future waste streams. The equipment is operated in the Remote Equipment Decontamination Cell (REDC), which is equipped with compressed air, two master-slave manipulators (MSM's) and an electro-mechanical manipulator (EMM) arm for operation of the remote tools. The REDC does not provide access to electrical power, so the equipment must be manuallymore » or pneumatically operated. The MSM's have a load limit at full extension of ten pounds, which limited the weight of the installation tool. In order to remotely replace Hanford connector gaskets several operations must be performed remotely, these include: removal of the spent gasket and retaining ring (retaining ring is also called snap ring), loading the new snap ring and gasket into the installation tool and installation of the new gasket into the Hanford connector. SRNL developed and tested tools that successfully perform all of the necessary tasks. Removal of snap rings from horizontal and vertical connectors is performed by separate air actuated retaining ring removal tools and is manipulated in the cell by the MSM. In order install a new gasket, the snap ring loader is used to load a new snap ring into a groove in the gasket installation tool. A new gasket is placed on the installation tool and retained by custom springs. An MSM lifts the installation tool and presses the mounted gasket against the connector block. Once the installation tool is in position, the gasket and snap ring are installed onto the connector by pneumatic actuation. All of the tools are located on a custom work table with a pneumatic valve station that directs compressed air to the desired tool and vents the tools as needed. Extensive testing of tooling operation was performed in the DWPF manipulator repair shop. This testing allowed the operators to gain confidence before the equipment was exposed to radioactive contamination. The testing also led to multiple design improvements. On July 17 and 29, 2008 the Remote Gasket Replacement Tooling was successfully demonstrated in the REDC at the DWPF of The Savannah River Site.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raszewski, F; Tommy Edwards, T; David Peeler, D

Sludge Batch 4 (SB4) is currently being processed in the Defense Waste Processing Facility (DWPF) using Frit 510. The slurry pumps in Tank 40 are experiencing in-leakage of bearing water, which is causing the sludge slurry in Tank 40 to become dilute at a rapid rate. Currently, the DWPF is removing this dilution water by performing caustic boiling during the Sludge Receipt and Adjustment Tank (SRAT) cycle. In order to alleviate prolonged SRAT cycle times, which may eventually impact canister production rates, the Liquid Waste Organization (LWO) performed a 100K gallon supernate decant of Tank 40 in April 2008. SRNLmore » performed a supplemental glass variability study to support the April 2008 100K gallon decant incorporating the impact of coupled operations (addition of the Actinide Removal Process (ARP) stream). Recently LWO requested that SRNL assess the impact of a second decant (up to 100K gallon) to the Frit 510-SB4 system. This second decant occurred in June 2008. LWO provided nominal compositions on May 6, 2008 representing Tank 40 prior to the second decant, following the second decant, and the SB4 Heel prior to blending with Tank 51 to constitute SB5. Paper study assessments were performed for these options based on sludge-only and coupled operations processing (ARP addition), as well as possible Na{sub 2}O additions (via NaOH additions) to both flowsheets. A review of the ComProTM database relative to the compositional region defined by the projections after the second decant coupled with Frit 510 identified only a few glasses with similar glass compositions. These glasses were acceptable from a durability perspective, but did not sufficiently cover the new glass compositional region. Therefore, SRNL recommended that a supplemental variability study be performed to support the June 2008 Tank 40 decant. Glasses were selected for the variability study based on three sludge compositional projections (sludge-only, coupled and coupled + 2 wt% Na{sub 2}O) at waste loadings (WLs) of interest to DWPF (32%, 35% and 38%). These nine glasses were fabricated and characterized using chemical composition analysis, X-ray Diffraction (XRD) and the Product Consistency Test (PCT). All of the glasses that were selected for this study satisfy the Product Composition Control System (PCCS) criteria and are deemed processable and acceptable for the DWPF, except for the SB4VS2-03 (sludge-only at 38% WL) target composition. This glass fails the T{sub L} criterion and would not be considered processable based on Slurry Mix Evaporator (SME) acceptability decisions. The durabilities of all of the study glasses (both quenched and ccc) are well below that of the normalized leachate for boron (NL [B]) of the reference EA glass (16.695 g/L) and are predictable using the current PCCS models. Very little variation exists between the NL [B] of the quenched and ccc versions of the glasses. There is some evidence of a trend toward a less durable glass as WL increases for some of the sludge projections. Frit 510 is a viable option for the processing of SB4 after a second Tank 40 decant with or without the addition of products from the ARP stream as well as the 2 wt% Na{sub 2}O addition. The addition of ARP had no negative impacts on the acceptability and predictability of the variability study glasses.« less

The regional cerebral blood flow changes in major depressive disorder with and without psychotic features.

PubMed

Gonul, Ali Saffet; Kula, Mustafa; Bilgin, Arzu Guler; Tutus, Ahmet; Oguz, Aslan

2004-09-01

Depressive patients with psychotic features demonstrate distinct biological abnormalities in the hypothalamic-pituitary-adrenal axis (HPA), dopaminergic activity, electroencephalogram sleep profiles and measures of serotonergic function when compared to nonpsychotic depressive patients. However, very few functional neuroimaging studies were specifically designed for studying the effects of psychotic features on neuroimaging findings in depressed patients. The objective of the present study was to compare brain Single Photon Emission Tomography (SPECT) images in a group of unmedicated depressive patients with and without psychotic features. Twenty-eight patients who fully met DSM-IV criteria for major depressive disorder (MDD, 12 had psychotic features) were included in the study. They were compared with 16 control subjects matched for age, gender and education. Both psychotic and nonpsychotic depressed patients showed significantly lower regional cerebral blood flow (rCBF) values in the left and right superior frontal cortex, and left anterior cingulate cortex compared to those of controls. In comparison with depressive patients without psychotic features (DwoPF), depressive patients with psychotic features (DwPF) showed significantly lower rCBF perfusion ratios in left parietal cortex, left cerebellum but had higher rCBF perfusion ratio in the left inferior frontal cortex and caudate nucleus. The present study showed that DwPF have a different rCBF pattern compared to patients without psychotic features. Abnormalities involving inferior frontal cortex, striatum and cerebellum may play an important role in the generation of psychotic symptoms in depression.

CHARACTERIZATION OF A PRECIPITATE REACTOR FEED TANK (PRFT) SAMPLE FROM THE DEFENSE WASTE PROCESSING FACILITY (DWPF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, C.; Bannochie, C.

2014-05-12

A sample of from the Defense Waste Processing Facility (DWPF) Precipitate Reactor Feed Tank (PRFT) was pulled and sent to the Savannah River National Laboratory (SRNL) in June of 2013. The PRFT in DWPF receives Actinide Removal Process (ARP)/ Monosodium Titanate (MST) material from the 512-S Facility via the 511-S Facility. This 2.2 L sample was to be used in small-scale DWPF chemical process cell testing in the Shielded Cells Facility of SRNL. A 1L sub-sample portion was characterized to determine the physical properties such as weight percent solids, density, particle size distribution and crystalline phase identification. Further chemical analysismore » of the PRFT filtrate and dissolved slurry included metals and anions as well as carbon and base analysis. This technical report describes the characterization and analysis of the PRFT sample from DWPF. At SRNL, the 2.2 L PRFT sample was composited from eleven separate samples received from DWPF. The visible solids were observed to be relatively quick settling which allowed for the rinsing of the original shipping vials with PRFT supernate on the same day as compositing. Most analyses were performed in triplicate except for particle size distribution (PSD), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and thermogravimetric analysis (TGA). PRFT slurry samples were dissolved using a mixed HNO3/HF acid for subsequent Inductively Coupled Plasma Atomic Emission Spectroscopy (ICPAES) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) analyses performed by SRNL Analytical Development (AD). Per the task request for this work, analysis of the PRFT slurry and filtrate for metals, anions, carbon and base were primarily performed to support the planned chemical process cell testing and to provide additional component concentrations in addition to the limited data available from DWPF. Analysis of the insoluble solids portion of the PRFT slurry was aimed at detailed characterization of these solids (TGA, PSD, XRD and SEM) in support of the Salt IPT chemistry team. The overall conclusions from analyses performed in this study are that the PRFT slurry consists of 0.61 Wt.% insoluble MST solids suspended in a 0.77 M [Na+] caustic solution containing various anions such as nitrate, nitrite, sulfate, carbonate and oxalate. The corresponding measured sulfur level in the PRFT slurry, a critical element for determining how much of the PRFT slurry gets blended into the SRAT, is 0.437 Wt.% TS. The PRFT slurry does not contain insoluble oxalates nor significant quantities of high activity sludge solids. The lack of sludge solids has been alluded to by the Salt IPT chemistry team in citing that the mixing pump has been removed from Tank 49H, the feed tank to ARP-MCU, thus allowing the sludge solids to settle out. The PRFT aqueous slurry from DWPF was found to contain 5.96 Wt.% total dried solids. Of these total dried solids, relatively low levels of insoluble solids (0.61 Wt.%) were measured. The densities of both the filtrate and slurry were 1.05 g/mL. Particle size distribution of the PRFT solids in filtered caustic simulant and XRD analysis of washed/dried PRFT solids indicate that the PRFT slurry contains a bimodal distribution of particles in the range of 1 and 6 μm and that the particles contain sodium titanium oxide hydroxide Na2Ti2O4(OH)2 crystalline material as determined by XRD. These data are in excellent agreement with similar data obtained from laboratory sampling of vendor supplied MST. Scanning Electron Microscopy (SEM) combined with Energy Dispersive X-ray Spectroscopy (EDS) analysis of washed/dried PRFT solids shows the particles to be like previous MST analyses consisting of irregular shaped micron-sized solids consisting primarily of Na and Ti. Thermogravimetric analysis of the washed and unwashed PRFT solids shows that the washed solids are very similar to MST solids. The TGA mass loss signal for the unwashed solids shows similar features to TGA performed on cellulose nitrate filter paper indicating significant presence of the deteriorated filter in this unwashed sample. Neither the washed nor unwashed PRFT solids TGA traces showed any features that would indicate presence of sodium oxalate solids. The PRFT Filtrate elemental analysis shows that Na, S and Al are major soluble species with trace levels of B, Cr, Cu, K, Li, Si, Tc, Th and U present. Nitrate, nitrite, sulfate, oxalate, carbonate and hydroxide are major soluble anion species. There is good agreement between the analyzed TOC and the total carbon calculated from the sum of oxalate and minor species formate. Comparison of the amount and speciation of the carbon species between filtrate and slurry indicates no significant carbon-containing species, e.g., sodium oxalate, are present in the slurry solids. Dissolution of the PRFT slurry and subsequent analysis shows that Na, Ti, Si and U are the major elements present on a Wt.% total dried solids basis with 30, 5.8 and 0.47 and 0.11 Wt.% total dried solids, respectively. The amount of Al in the dissolved PRFT slurry is less than that calculated from the PRFT filtrate alone which suggests that the mixed acid digestion used in this work is not optimized for Al recovery. The concentrations of Ca, Fe, Hg and U are all low (at or below 0.11 wt%) and there is no detectable Mn or Ni present which indicates no significant HLW sludge solids are present in the PRFT slurry sample.« less

Phase 2 Report--Mercury Behavior In The Defense Waste Processing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C.; Fellinger, T.

2016-07-27

The purpose of this report is to provide a summary of the DWPF processing history in regards to mercury, document the mercury results obtained on the product and condensate samples, and provide further recommendations based on the data obtained.

Characterization of the SRNL-Washed tank 51 sludge batch 9 qualification sample

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J. M.

2016-01-01

Savannah River National Laboratory (SRNL) personnel have been requested to qualify the next sludge batch (Sludge Batch 9 – SB9) for processing at the Defense Waste Processing Facility (DWPF). To accomplish this task, Savannah River Remediation (SRR) sent SRNL a 3-L sample of Tank 51H slurry to be characterized, washed, and then used in a lab-scale demonstration of the DWPF flowsheet (after combining with Tank 40H sludge). SRNL has washed the Tank 51H sample per the Tank Farm washing strategy as of October 20, 2015. A part of the qualification process is extensive radionuclide and chemical characterization of the SRNL-washedmore » Tank 51H slurry. This report documents the chemical characterization of the washed slurry; radiological characterization is in progress and will be documented in a separate report. The analytical results of this characterization are comparable to the Tank Farm projections. Therefore, it is recommended that SRNL use this washed slurry for the ongoing SB9 qualification activities.« less

Inhibition Of Washed Sludge With Sodium Nitrite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Congdon, J. W.; Lozier, J. S.

2012-09-25

This report describes the results of electrochemical tests used to determine the relationship between the concentration of the aggressive anions in washed sludge and the minimum effective inhibitor concentration. Sodium nitrate was added as the inhibitor because of its compatibility with the DWPF process. A minimum of 0.05M nitrite is required to inhibit the washed sludge simulant solution used in this study. When the worst case compositions and safety margins are considered, it is expected that a minimum operating limit of nearly 0.1M nitrite will be specified. The validity of this limit is dependent on the accuracy of the concentrationsmore » and solubility splits previously reported. Sodium nitrite additions to obtain 0.1M nitrite concentrations in washed sludge will necessitate the additional washing of washed precipitate in order to decrease its sodium nitrite inhibitor requirements sufficiently to remain below the sodium limits in the feed to the DWPF. Nitrite will be the controlling anion in "fresh" washed sludge unless the soluble chloride concentration is about ten times higher than predicted by the solubility splits. Inhibition of "aged" washed sludge will not be a problem unless significant chloride dissolution occurs during storage. It will be very important tomonitor the composition of washed sludge during processing and storage.« less

Hydrogen Production in Radioactive Solutions in the Defense Waste Processing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

CRAWFORD, CHARLES L.

2004-05-26

In the radioactive slurries and solutions to be processed in the Defense Waste Processing Facility (DWPF), hydrogen will be produced continuously by radiolysis. This production results from alpha, beta, and gamma rays from decay of radionuclides in the slurries and solutions interacting with the water. More than 1000 research reports have published data concerning this radiolytic production. The results of these studies have been reviewed in a comprehensive monograph. Information about radiolytic hydrogen production from the different process tanks is necessary to determine air purge rates necessary to prevent flammable mixtures from accumulating in the vapor spaces above these tanks.more » Radiolytic hydrogen production rates are usually presented in terms of G values or molecules of hydrogen produced per 100ev of radioactive decay energy absorbed by the slurry or solution. With the G value for hydrogen production, G(H2), for a particular slurry and the concentrations of radioactive species in that slurry, the rate of H2 production for that slurry can be calculated. An earlier investigation estimated that the maximum rate that hydrogen could be produced from the sludge slurry stream to the DWPF is with a G value of 0.45 molecules per 100ev of radioactive decay energy sorbed by the slurry.« less

High-Level Waste System Process Interface Description

DOE Office of Scientific and Technical Information (OSTI.GOV)

d'Entremont, P.D.

1999-01-14

The High-Level Waste System is a set of six different processes interconnected by pipelines. These processes function as one large treatment plant that receives, stores, and treats high-level wastes from various generators at SRS and converts them into forms suitable for final disposal. The three major forms are borosilicate glass, which will be eventually disposed of in a Federal Repository, Saltstone to be buried on site, and treated water effluent that is released to the environment.

Mercury Phase II Study - Mercury Behavior across the High-Level Waste Evaporator System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.; Crawford, C. L.; Jackson, D. G.

2016-06-17

The Mercury Program team’s effort continues to develop more fundamental information concerning mercury behavior across the liquid waste facilities and unit operations. Previously, the team examined the mercury chemistry across salt processing, including the Actinide Removal Process/Modular Caustic Side Solvent Extraction Unit (ARP/MCU), and the Defense Waste Processing Facility (DWPF) flowsheets. This report documents the data and understanding of mercury across the high level waste 2H and 3H evaporator systems.

TANK 40 FINAL SB7B CHEMICAL CHARACTERIZATION RESULTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C.

2012-03-15

A sample of Sludge Batch 7b (SB7b) was taken from Tank 40 in order to obtain radionuclide inventory analyses necessary for compliance with the Waste Acceptance Product Specifications (WAPS). The SB7b WAPS sample was also analyzed for chemical composition including noble metals and fissile constituents, and these results are reported here. These analyses along with the WAPS radionuclide analyses will help define the composition of the sludge in Tank 40 that is currently being fed to the Defense Waste Processing Facility (DWPF) as SB7b. At the Savannah River National Laboratory (SRNL) the 3-L Tank 40 SB7b sample was transferred frommore » the shipping container into a 4-L high density polyethylene bottle and solids were allowed to settle over the weekend. Supernate was then siphoned off and circulated through the shipping container to complete the transfer of the sample. Following thorough mixing of the 3-L sample, a 558 g sub-sample was removed. This sub-sample was then utilized for all subsequent analytical samples. Eight separate aliquots of the slurry were digested, four with HNO{sub 3}/HCl (aqua regia) in sealed Teflon{reg_sign} vessels and four with NaOH/Na{sub 2}O{sub 2} (alkali or peroxide fusion) using Zr crucibles. Two Analytical Reference Glass - 1 (ARG-1) standards were digested along with a blank for each preparation. Each aqua regia digestion and blank was diluted to 1:100 mL with deionized water and submitted to Analytical Development (AD) for inductively coupled plasma - atomic emission spectroscopy (ICP-AES) analysis, inductively coupled plasma - mass spectrometry (ICP-MS) analysis, atomic absorption spectroscopy (AA) for As and Se, and cold vapor atomic absorption spectroscopy (CV-AA) for Hg. Equivalent dilutions of the alkali fusion digestions and blank were submitted to AD for ICP-AES analysis. Tank 40 SB7b supernate was collected from a mixed slurry sample in the SRNL Shielded Cells and submitted to AD for ICP-AES, ion chromatography (IC), total base/free OH{sup -}/other base, total inorganic carbon/total organic carbon (TIC/TOC) analyses, and Cs-137 gamma scan. Weighted dilutions of slurry were submitted for IC, TIC/TOC, and total base/free OH{sup -}/other base analyses. Activities for U-233, U-235, and Pu-239 were determined from the ICP-MS data for the aqua regia digestions of the Tank 40 WAPS slurry using the specific activity of each isotope. The Pu-241 value was determined from a Pu-238/-241 method developed by SRNL AD and previously described. The following conclusions were drawn from the analytical results reported here: (1) The ratios of the major elements for the SB7b WAPS sample are different from those measured for the SB7a WAPS sample. There is less Al and Mn relative to Fe than the previous sludge batch. (2) The elemental composition of this sample and the analyses conducted here are reasonable and consistent with DWPF batch data measurements in light of DWPF pre-sample concentration and SRAT product heel contributions to the DWPF SRAT receipt analyses. The element ratios for Al/Fe, Ca/Fe, Mn/Fe, and U/Fe agree within 10% between this work and the DWPF Sludge Receipt and Adjustment Tank (SRAT) receipt analyses. (3) Sulfur in the SB7b WAPS sample is 82% soluble, slightly less than results reported for SB3, SB4, and SB6 samples but unlike the 50% insoluble sulfur observed in the SB5 WAPS sample. In addition, 23% of the soluble sulfur is not present as sulfate in SB7b. (4) The average activities of the fissile isotopes of interest in the SB7b WAPS sample are (in {mu}Ci/g of total dried solids): 4.22E-02 U-233, 6.12E-04 U-235, 1.08E+01 Pu-239, and 5.09E+01 Pu-241. The full radionuclide composition will be reported in a future document. (5) The fission product noble metal and Ag concentrations appear to have largely peaked in previous DWPF sludge batches, with the exception of Ru, which still shows a slight increase in SB7b.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiedenman, B. J.; White, T. L.; Mahannah, R. N.

Ion Chromatography (IC) is the principal analytical method used to support studies of Sludge Reciept and Adjustment Tank (SRAT) chemistry at DWPF. A series of prior analytical ''Round Robin'' (RR) studies included both supernate and sludge samples from SRAT simulant, previously reported as memos, are tabulated in this report.2,3 From these studies it was determined to standardize IC column size to 4 mm diameter, eliminating the capillary column from use. As a follow on test, the DWPF laboratory, the PSAL laboratory, and the AD laboratory participated in the current analytical RR to determine a suite of anions in SRAT simulantmore » by IC, results also are tabulated in this report. The particular goal was to confirm the laboratories ability to measure and quantitate glycolate ion. The target was + or - 20% inter-lab agreement of the analyte averages for the RR. Each of the three laboratories analyzed a batch of 12 samples. For each laboratory, the percent relative standard deviation (%RSD) of the averages on nitrate, glycolate, and oxalate, was 10% or less. The three laboratories all met the goal of 20% relative agreement for nitrate and glycolate. For oxalate, the PSAL laboratory reported an average value that was 20% higher than the average values reported by the DWPF laboratory and the AD laboratory. Because of this wider window of agreement, it was concluded to continue the practice of an additional acid digestion for total oxalate measurement. It should also be noted that large amounts of glycolate in the SRAT samples will have an impact on detection limits of near eluting peaks, namely Fluoride and Formate. A suite of scoping experiments are presented in the report to identify and isolate other potential interlaboratory disceprancies. Specific ion chromatography inter-laboratory method conditions and differences are tabulated. Most differences were minor but there are some temperature control equipment differences that are significant leading to a recommendation of a heated jacket for analytical columns that are remoted for use in radiohoods. A suggested method improvement would be to implement column temperture control at a temperature slightly above ambient to avoid peak shifting due to temperature fluctuations. Temperature control in this manner would improve short and longer term peak retention time stability. An unknown peak was observed during the analysis of glycolic acid and SRAT simulant. The unknown peak was determined to best match diglycolic acid. The development of a method for acetate is summaraized, and no significant amount of acetate was observed in the SRAT products tested. In addition, an alternative Gas Chromatograph (GC) method for glycolate is summarized.« less

DETERMINATION OF REPORTABLE RADIONUCLIDES FOR DWPF SLUDGE BATCH 7B (MACROBATCH 9)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, C. L.; Diprete, D. P.

The Waste Acceptance Product Specifications (WAPS) 1.2 require that “The Producer shall report the inventory of radionuclides (in Curies) that have half-lives longer than 10 years and that are, or will be, present in concentrations greater than 0.05 percent of the total inventory for each waste type indexed to the years 2015 and 3115”. As part of the strategy to comply with WAPS 1.2, the Defense Waste Processing Facility (DWPF) will report for each waste type, all radionuclides (with half-lives greater than 10 years) that have concentrations greater than 0.01 percent of the total inventory from time of production throughmore » the 1100 year period from 2015 through 3115. The initial listing of radionuclides to be included is based on the design-basis glass as identified in the Waste Form Compliance Plan (WCP) and Waste Form Qualification Report (WQR). However, it is required that this list be expanded if other radionuclides with half-lives greater than 10 years are identified that may meet the greater than 0.01% criterion for Curie content. Specification 1.6 of the WAPS, International Atomic Energy Agency (IAEA) Safeguards Reporting for High Level Waste (HLW), requires that the ratio by weights of the following uranium and plutonium isotopes be reported: U-233, U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, and Pu- 242. Therefore, the complete set of reportable radionuclides must also include this set of U and Pu isotopes. The DWPF is receiving radioactive sludge slurry from HLW Tank 40. The radioactive sludge slurry in Tank 40 is a blend of the heel from Sludge Batch 7a (SB7a) and Sludge Batch 7b (SB7b) that was transferred to Tank 40 from Tank 51. The blend of sludge in Tank 40 is also referred to as Macrobatch 9 (MB9). This report develops the list of reportable radionuclides and associated activities as a function of time. The DWPF will use this list and the activities as one of the inputs for the development of the Production Records that relate to radionuclide inventory. This work was initiated through Technical Task Request (TTR) HLW-DWPF-TTR-2011-0004; Rev. 0 entitled Sludge Batch 7b Qualification Studies. Specifically, this report details results from performing Subtask II, Item 2 of the TTR and, in part, meets Deliverable 6 of the TTR. The work was performed following the Task Technical and Quality Assurance Plan (TTQAP), SRNL-RP-2011-00247, Rev. 0 and Analytical Study Plan (ASP), SRNL-RP-2011-00248, Rev. 0. In order to determine the reportable radionuclides for SB7b (MB9), a list of radioisotopes that may meet the criteria as specified by the Department of Energy’s (DOE) WAPS was developed. All radioactive U- 235 fission products and all radioactive activation products that could be in the SRS HLW were considered. In addition, all U and Pu isotopes identified in WAPS 1.6 were included in the list. This list was then evaluated and some isotopes were excluded from the projection calculations. Based on measurements and analytical detection limits, 27 radionuclides have been identified as reportable for DWPF SB7b as specified by WAPS 1.2. The WCP and WQR require that all of the radionuclides present in the Design Basis glass be considered as the initial set of reportable radionuclides. For SB7b, all of the radionuclides in the Design Basis glass are reportable except for three radionuclides: Pd-107, Cs-135, and Th-230. At no time during the 1100- year period between 2015 and 3115 did any of these three radionuclides contribute to more than 0.01% of the radioactivity on a Curie basis. Two additional uranium isotopes (U-235 and -236) must be added to the list of reportable radionuclides in order to meet WAPS 1.6. All of the Pu isotopes (Pu-238, -239, -240, -241, and -242) and other U isotopes (U-233, -234, and -238) identified in WAPS 1.6 were already determined to be reportable according to WAPS 1.2 This brings the total number of reportable radionuclides for SB7b to 29. The radionuclide measurements made for SB7b are similar to those performed in the previous SB7a MB8 work. Some method development/refinement occurred during the conduct of these measurements, leading to lower detection limits and more accurate measurement of some isotopes than was previously possible. Improvement in the analytical measurements will likely continue, and this in turn should lead to improved detection limit values for some radionuclides and actual measurements for still others.« less

Determination Of Reportable Radionuclides For DWPF Sludge Batch 7B (Macrobatch 9)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, C. L.; DiPrete, D. P.

The Waste Acceptance Product Specifications (WAPS) 1.2 require that “The Producer shall report the inventory of radionuclides (in Curies) that have half-lives longer than 10 years and that are, or will be, present in concentrations greater than 0.05 percent of the total inventory for each waste type indexed to the years 2015 and 3115”. As part of the strategy to comply with WAPS 1.2, the Defense Waste Processing Facility (DWPF) will report for each waste type, all radionuclides (with half-lives greater than 10 years) that have concentrations greater than 0.01 percent of the total inventory from time of production throughmore » the 1100 year period from 2015 through 3115. The initial listing of radionuclides to be included is based on the design-basis glass as identified in the Waste Form Compliance Plan (WCP) and Waste Form Qualification Report (WQR). However, it is required that this list be expanded if other radionuclides with half-lives greater than 10 years are identified that may meet the greater than 0.01% criterion for Curie content. Specification 1.6 of the WAPS, International Atomic Energy Agency (IAEA) Safeguards Reporting for High Level Waste (HLW), requires that the ratio by weights of the following uranium and plutonium isotopes be reported: U-233, U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, and Pu-242. Therefore, the complete set of reportable radionuclides must also include this set of U and Pu isotopes. The DWPF is receiving radioactive sludge slurry from HLW Tank 40. The radioactive sludge slurry in Tank 40 is a blend of the heel from Sludge Batch 7a (SB7a) and Sludge Batch 7b (SB7b) that was transferred to Tank 40 from Tank 51. The blend of sludge in Tank 40 is also referred to as Macrobatch 9 (MB9). This report develops the list of reportable radionuclides and associated activities as a function of time. The DWPF will use this list and the activities as one of the inputs for the development of the Production Records that relate to radionuclide inventory. This work was initiated through Technical Task Request (TTR) HLW-DWPF-TTR-2011-0004; Rev. 0 entitled Sludge Batch 7b Qualification Studies. Specifically, this report details results from performing Subtask II, Item 2 of the TTR and, in part, meets Deliverable 6 of the TTR. The work was performed following the Task Technical and Quality Assurance Plan (TTQAP), SRNL-RP-2011-00247, Rev. 0 and Analytical Study Plan (ASP), SRNL-RP-2011-00248, Rev. 0. In order to determine the reportable radionuclides for SB7b (MB9), a list of radioisotopes that may meet the criteria as specified by the Department of Energy’s (DOE) WAPS was developed. All radioactive U-235 fission products and all radioactive activation products that could be in the SRS HLW were considered. In addition, all U and Pu isotopes identified in WAPS 1.6 were included in the list. This list was then evaluated and some isotopes were excluded from the projection calculations. Based on measurements and analytical detection limits, 27 radionuclides have been identified as reportable for DWPF SB7b as specified by WAPS 1.2. The WCP and WQR require that all of the radionuclides present in the Design Basis glass be considered as the initial set of reportable radionuclides. For SB7b, all of the radionuclides in the Design Basis glass are reportable except for three radionuclides: Pd-107, Cs-135, and Th-230. At no time during the 1100-year period between 2015 and 3115 did any of these three radionuclides contribute to more than 0.01% of the radioactivity on a Curie basis. Two additional uranium isotopes (U-235 and -236) must be added to the list of reportable radionuclides in order to meet WAPS 1.6. All of the Pu isotopes (Pu-238, -239, -240, -241, and -242) and other U isotopes (U-233, -234, and -238) identified in WAPS 1.6 were already determined to be reportable according to WAPS 1.2 This brings the total number of reportable radionuclides for SB7b to 29. The radionuclide measurements made for SB7b are similar to those performed in the previous SB7a MB8 work. Some method development/refinement occurred during the conduct of these measurements, leading to lower detection limits and more accurate measurement of some isotopes than was previously possible. Improvement in the analytical measurements will likely continue, and this in turn should lead to improved detection limit values for some radionuclides and actual measurements for still others.« less

The Impact Of The MCU Life Extension Solvent On Sludge Batch 8 Projected Operating Windows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D. K.; Edwards, T. B.; Stone, M. E.

2013-08-14

As a part of the Actinide Removal Process (ARP)/Modular Caustic Side Solvent Extraction Unit (MCU) Life Extension Project, a next generation solvent (NGS) and a new strip acid will be deployed. The strip acid will be changed from dilute nitric acid to dilute boric acid (0.01 M). Because of these changes, experimental testing or evaluations with the next generation solvent are required to determine the impact of these changes (if any) to Chemical Process Cell (CPC) activities, glass formulation strategies, and melter operations at the Defense Waste Processing Facility (DWPF). The introduction of the dilute (0.01M) boric acid stream intomore » the DWPF flowsheet has a potential impact on glass formulation and frit development efforts since B2O3 is a major oxide in frits developed for DWPF. Prior knowledge of this stream can be accounted for during frit development efforts but that was not the case for Sludge Batch 8 (SB8). Frit 803 has already been recommended and procured for SB8 processing; altering the frit to account for the incoming boron from the strip effluent (SE) is not an option for SB8. Therefore, the operational robustness of Frit 803 to the introduction of SE including its compositional tolerances (i.e., up to 0.0125M boric acid) is of interest and was the focus of this study. The primary question to be addressed in the current study was: What is the impact (if any) on the projected operating windows for the Frit 803 – SB8 flowsheet to additions of B2O3 from the SE in the Sludge Receipt and Adjustment Tank (SRAT)? More specifically, will Frit 803 be robust to the potential compositional changes occurring in the SRAT due to sludge variation, varying additions of ARP and/or the introduction of SE by providing access to waste loadings (WLs) of interest to DWPF? The Measurement Acceptability Region (MAR) results indicate there is very little, if any, impact on the projected operating windows for the Frit 803 – SB8 system regardless of the presence or absence of ARP and SE (up to 2 wt% B2O3 contained in the SRAT and up to 2000 gallons of ARP). It should be noted that 0.95 wt% B2O3 is the nominal projected concentration in the SRAT based on a 0.0125M boric acid flowsheet with 70,000 liters of SE being added to the SRAT. The impact on CPC processing of a 0.01M boric acid solution for elution of cesium during Modular Caustic Side Solvent Extraction Unit (MCU) processing has previously been evaluated by the Savannah River National Laboratory (SRNL). Increasing the acid strength to 0.0125M boric acid to account for variations in the boric acid strength has been reviewed versus the previous evaluation. The amount of acid from the boric acid represented approximately 5% of the total acid during the previous evaluation. An increase from 0.01 to 0.0125M boric acid represents a change of approximately 1.3% which is well within the error of the acid calculation. Therefore, no significant changes to CPC processing (hydrogen generation, metal solubilities, rheological properties, REDOX control, etc.) are expected from an increase in allowable boric acid concentration from 0.01M to 0.0125M.« less

DEVELOPMENT OF AN ANTIFOAM TRACKING SYSTEM AS AN OPTION TO SUPPORT THE MELTER OFF-GAS FLAMMABILITY CONTROL STRATEGY AT THE DWPF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.; Lambert, D.

The Savannah River National Laboratory (SRNL) has been working with the Savannah River Remediation (SRR) Defense Waste Processing Facility (DWPF) in the development and implementation of an additional strategy for confidently satisfying the flammability controls for DWPF’s melter operation. An initial strategy for implementing the operational constraints associated with flammability control in DWPF was based upon an analytically determined carbon concentration from antifoam. Due to the conservative error structure associated with the analytical approach, its implementation has significantly reduced the operating window for processing and has led to recurrent Slurry Mix Evaporator (SME) and Melter Feed Tank (MFT) remediation. Tomore » address the adverse operating impact of the current implementation strategy, SRR issued a Technical Task Request (TTR) to SRNL requesting the development and documentation of an alternate strategy for evaluating the carbon contribution from antifoam. The proposed strategy presented in this report was developed under the guidance of a Task Technical and Quality Assurance Plan (TTQAP) and involves calculating the carbon concentration from antifoam based upon the actual mass of antifoam added to the process assuming 100% retention. The mass of antifoam in the Additive Mix Feed Tank (AMFT), in the Sludge Receipt and Adjustment Tank (SRAT), and in the SME is tracked by mass balance as part of this strategy. As these quantities are monitored, the random and bias uncertainties affecting their values are also maintained and accounted for. This report documents: 1) the development of an alternate implementation strategy and associated equations describing the carbon concentration from antifoam in each SME batch derived from the actual amount of antifoam introduced into the AMFT, SRAT, and SME during the processing of the batch. 2) the equations and error structure for incorporating the proposed strategy into melter off-gas flammability assessments. Sample calculations of the system are also included in this report. Please note that the system developed and documented in this report is intended as an alternative to the current, analytically-driven system being utilized by DWPF; the proposed system is not intended to eliminate the current system. Also note that the system developed in this report to track antifoam mass in the AMFT, SRAT, and SME will be applicable beyond just Sludge Batch 8. While the model used to determine acceptability of the SME product with respect to melter off-gas flammability controls must be reassessed for each change in sludge batch, the antifoam mass tracking methodology is independent of sludge batch composition and as such will be transferable to future sludge batches.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jannik, Tim; Hartman, Larry

During the operational history of Savannah River Site, many different radionuclides have been released from site facilities. However, as shown in this analysis, only a relatively small number of the released radionuclides have been significant contributors to doses to the offsite public. This report is an update to the 2011 analysis, Critical Radionuclide and Pathway Analysis for the Savannah River Site. SRS-based Performance Assessments for E-Area, Saltstone, F-Tank Farm, H-Tank Farm, and a Comprehensive SRS Composite Analysis have been completed. The critical radionuclides and pathways identified in those extensive reports are also detailed and included in this analysis.

Glycolic acid physical properties and impurities assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D. P.; Pickenheim, B. R.; Bibler, N. E.

This document has been revised due to recent information that the glycolic acid used in Savannah River National Laboratory (SRNL) experiments contains both formaldehyde and methoxyacetic acid. These impurities were in the glycolic acid used in the testing included in this report and in subsequent testing using DuPont (now called Chemours) supplied Technical Grade 70 wt% glycolic acid. However, these impurities were not reported in earlier revisions. Additional data concerning the properties of glycolic acid have also been added to this report. The Defense Waste Processing Facility (DWPF) is planning to implement a nitric-glycolic acid flowsheets to increase attainment tomore » meet closure commitment dates during Sludge Batch 9. In fiscal year 2009, SRNL was requested to determine the physical properties of formic and glycolic acid blends. Blends of formic acid in glycolic acid were prepared and their physical properties tested. Increasing amounts of glycolic acid led to increases in blend density, viscosity and surface tension as compared to the 90 wt% formic acid that is currently used at DWPF. These increases are small, however, and are not expected to present any difficulties in terms of processing. The effect of sulfur impurities in Technical Grade glycolic acid was studied for its impact on DWPF glass quality. While the glycolic acid specification allows for more sulfate than the current formic acid specification, the ultimate impact is expected to be on the order of 0.033 wt% sulfur in glass. Note that lower sulfur content glycolic acid could likely be procured at some increased cost if deemed necessary. A paper study on the effects of radiation on glycolic acid was performed. The analysis indicates that substitution of glycolic acid for formic acid would not increase the radiolytic production rate of H2 and cause an adverse effect in the Slurry Receipt and Adjustment Tank (SRAT) or Slurry Mix Evaporator (SME) process. It has been cited that glycolic acid solutions that are depleted of O2 when subjected to large radiation doses produced considerable quantities of a non-diffusive polymeric material. Considering a constant air purge is maintained in the SRAT and the solution is continuously mixed, oxygen depletion seems unlikely, however, if this polymer is formed in the SRAT solution, the rheology of the solution may be affected and pumping of the solution may be hindered. However, an irradiation test with a simulated SRAT product supernate containing glycolic acid in an oxygen depleted atmosphere found no evidence of polymerization.« less

ACTUAL WASTE TESTING OF GYCOLATE IMPACTS ON THE SRS TANK FARM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martino, C.

2014-05-28

Glycolic acid is being studied as a replacement for formic acid in the Defense Waste Processing Facility (DWPF) feed preparation process. After implementation, the recycle stream from DWPF back to the high-level waste Tank Farm will contain soluble sodium glycolate. Most of the potential impacts of glycolate in the Tank Farm were addressed via a literature review and simulant testing, but several outstanding issues remained. This report documents the actual-waste tests to determine the impacts of glycolate on storage and evaporation of Savannah River Site high-level waste. The objectives of this study are to address the following: Determine the extentmore » to which sludge constituents (Pu, U, Fe, etc.) dissolve (the solubility of sludge constituents) in the glycolate-containing 2H-evaporator feed. Determine the impact of glycolate on the sorption of fissile (Pu, U, etc.) components onto sodium aluminosilicate solids. The first objective was accomplished through actual-waste testing using Tank 43H and 38H supernatant and Tank 51H sludge at Tank Farm storage conditions. The second objective was accomplished by contacting actual 2H-evaporator scale with the products from the testing for the first objective. There is no anticipated impact of up to 10 g/L of glycolate in DWPF recycle to the Tank Farm on tank waste component solubilities as investigated in this test. Most components were not influenced by glycolate during solubility tests, including major components such as aluminum, sodium, and most salt anions. There was potentially a slight increase in soluble iron with added glycolate, but the soluble iron concentration remained so low (on the order of 10 mg/L) as to not impact the iron to fissile ratio in sludge. Uranium and plutonium appear to have been supersaturated in 2H-evaporator feed solution mixture used for this testing. As a result, there was a reduction of soluble uranium and plutonium as a function of time. The change in soluble uranium concentration was independent of added glycolate concentration. The change in soluble plutonium content was dependent on the added glycolate concentration, with higher levels of glycolate (5 g/L and 10 g/L) appearing to suppress the plutonium solubility. The inclusion of glycolate did not change the dissolution of or sorption onto actual-waste 2H-evaporator pot scale to an extent that will impact Tank Farm storage and concentration. The effects that were noted involved dissolution of components from evaporator scale and precipitation of components onto evaporator scale that were independent of the level of added glycolate.« less

SDU6 Interior Liner Testing & Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skidmore, T. E.

Two liner materials (Marseal® M-3500 and REMA Chemoline® 4CN) proposed for use as a liner inside the Saltstone Disposal Unit 6 (SDU6) were subjected to specific ASTM tests (tensile and lap-shear) after immersion in 50% and 100% simulant solutions for 1000 hours at the Savannah River Ecology Laboratory. Both liner materials exhibited good resistance to the simulant chemistry, at least based on the tests performed and the test duration/conditions imposed. In lap-shear tests, both materials failed in the base material rather than peeling apart, confirming good adhesion. The REMA 4CN bromobutyl elastomer showed superior bonding characteristics and absence of warpingmore » or delamination at the conditions tested. The Marseal M-3500 material (PVC/EVA blend with polyester reinforcement) exhibited deformation and debonding in some locations. The cause of the deformation and delamination observed in the Marseal M-3500 material is not fully known, but possibly attributed to thermomechanical stress at immersion temperatures, and the thermoplastic nature of the material. The immersion temperature (68 °C) is slightly greater than the maximum use temperature limit quoted for the Marseal M- 3500 liner (65 °C), though the basis for the service limit is unknown. The testing performed was limited in scope and only for these two liner materials. These tests were primarily performed to screen for severe incompatibility or short-term degradation in Saltstone bleedwater simulants at bounding solution temperatures. Additional testing is recommended to assess long-term performance and the overall service life of the liner.« less

Simulated Waste Testing Of Glycolate Impacts On The 2H-Evaporator System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martino, C. J.

2013-08-13

Glycolic acid is being studied as a total or partial replacement for formic acid in the Defense Waste Processing Facility (DWPF) feed preparation process. After implementation, the recycle stream from DWPF back to the high-level waste tank farm will contain soluble sodium glycolate. Most of the potential impacts of glycolate in the tank farm were addressed via a literature review, but several outstanding issues remained. This report documents the non-radioactive simulant tests impacts of glycolate on storage and evaporation of Savannah River Site high-level waste. The testing for which non-radioactive simulants could be used involved the following: the partitioning ofmore » glycolate into the evaporator condensate, the impacts of glycolate on metal solubility, and the impacts of glycolate on the formation and dissolution of sodium aluminosilicate scale within the evaporator. The following are among the conclusions from this work: Evaporator condensate did not contain appreciable amounts of glycolate anion. Of all tests, the highest glycolate concentration in the evaporator condensate was 0.38 mg/L. A significant portion of the tests had glycolate concentration in the condensate at less than the limit of quantification (0.1 mg/L). At ambient conditions, evaporator testing did not show significant effects of glycolate on the soluble components in the evaporator concentrates. Testing with sodalite solids and silicon containing solutions did not show significant effects of glycolate on sodium aluminosilicate formation or dissolution.« less

Bubblers Speed Nuclear Waste Processing at SRS

ScienceCinema

None

2018-05-23

At the Department of Energy's Savannah River Site, American Recovery and Reinvestment Act funding has supported installation of bubbler technology and related enhancements in the Defense Waste Processing Facility (DWPF). The improvements will accelerate the processing of radioactive waste into a safe, stable form for storage and permit expedited closure of underground waste tanks holding 37 million gallons of liquid nuclear waste.

DWPF DECON FRIT: SUMP AND SLURRY SOLIDS ANALYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, C.; Peeler, D.; Click, D.

The Savannah River National Laboratory (SRNL) has been requested to perform analyses on samples of the Defense Waste Processing Facility (DWPF) decon frit slurry (i.e., supernate samples and sump solid samples). Four 1-L liquid slurry samples were provided to SRNL by Savannah River Remediation (SRR) from the 'front-end' decon activities. Additionally, two 1-L sump solids samples were provided to SRNL for compositional and physical analysis. In this report, the physical and chemical characterization results of the slurry solids and sump solids are reported. Crawford et al. (2010) provide the results of the supernate analysis. The results of the sump solidsmore » are reported on a mass basis given the samples were essentially dry upon receipt. The results of the slurry solids were converted to a volume basis given approximately 2.4 grams of slurry solids were obtained from the {approx}4 liters of liquid slurry sample. Although there were slight differences in the analytical results between the sump solids and slurry solids the following general summary statements can be made. Slight differences in the results are also captured for specific analysis. (1) Physical characterization - (a) SEM/EDS analysis suggested that the samples were enriched in Li and Si (B and Na not detectable using the current EDS system) which is consistent with two of the four principle oxides of Frit 418 (B{sub 2}O{sub 3}, Na{sub 2}O, Li{sub 2}O and SiO{sub 2}). (b) SEM/EDS analysis also identified impurities which were elementally consistent with stainless steel (i.e., Fe, Ni, Cr contamination). (c) XRD results indicated that the sump solids samples were amorphous which is consistent with XRD results expected for a Frit 418 based sample. (d) For the sump solids, SEM/EDS analysis indicated that the particle size of the sump solids were consistent with that of an as received Frit 418 sample from a current DWPF vendor. (e) For the slurry solids, SEM/EDS analysis indicated that the particle size range of the slurry solids was much broader than compared to the sump solids. More specifically, there were significantly more fines in the slurry solids as compared to the sump solids. (f) PSD results indicated that > 99% of both the sump and slurry solids were less than 350 microns. The PSD results also supported SEM/EDS analysis that there were significantly more fines in the slurry solids as compared to the sump solids. (2) Weight Percent Solids - Based on the measured supernate density and mass of insoluble solids (2.388 grams) filtered from the four liters of liquid slurry samples, the weight percent insoluble solids was estimated to be 0.060 wt%. This level of insoluble solids is higher than the ETP WAC limit of 100 mg/L, or 0.01 wt% which suggests a separation technology of some type would be required. (3) Chemical Analysis - (a) Elemental results from ICP-ES analysis indicated that the sump solids and slurry were very consistent with the nominal composition of Frit 418. There were other elements identified by ICP analysis which were either consistent with the presence of stainless steel (as identified by SEM/EDS analysis) or impurities that have been observed in 'as received' Frit 418 from the vendor. (b) IC anion analysis of the sump solids and slurry solids indicated all of the species were less than detection limits. (c) Radionuclide analysis of the sump solids also indicated that most of the analytes were either at or below the detection limits. (d) Organic analysis of the sump solids and slurry solids indicated all of the species were less than detection limits. It should be noted that the results of this study may not be representative of future decon frit solutions or sump/slurry solids samples. Therefore, future DWPF decisions regarding the possible disposal pathways for either the aqueous or solid portions of the Decon Frit system need to factor in the potential differences. More specifically, introduction of a different frit or changes to other DWPF flowsheet unit operations (e.g., different sludge batch or coupling with other process streams) may impact not only the results but also the conclusions regarding acceptability with respect to the ETF WAC limits or other alternative disposal options.« less

Technetium Sorption By Cementitious Materials Under Reducing Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaplan, Daniel I.; Estes, Shanna L.; Arai, Yuji

2013-07-18

The objective of this study was to measure Tc sorption to cementitious materials under reducing conditions to simulate Saltstone Disposal Facility conditions. Earlier studies were conducted and the experimental conditions were found not to simulate those of the facility. Through a five month subcontract with Clemson University, sorption of {sup 99}Tc to four cementitious materials was examined within an anaerobic glovebag targeting a 0.1% H{sub 2}(g)/ 99.9% N{sub 2}(g) atmosphere. Early experiments based on Tc sorption and Eh indicated that 0.1% H{sub 2}(g) (a reductant) was necessary to preclude experimental impacts from O{sub 2}(g) diffusion into the glovebag. Preliminary datamore » to date (up to 56 days) indicates that sorption of {sup 99}Tc to cementitious materials increased with increasing slag content for simulated saltstone samples. This is consistent with the conceptual model that redox active sulfide groups within the reducing slag facilitate reduction of Tc(VII) to Tc(IV). These experiments differ from previous experiments where a 2% H{sub 2}(g) atmosphere was maintained (Kaplan et al., 2011 (SRNL-STI-2010-00668)). The impact of the 2% H{sub 2}(g) reducing atmosphere on this data was examined and determined to cause the reduction of Tc in experimental samples without slag. In the present ongoing study, after 56 days, Tc sorption by the 50-year old cement samples (no slag) was undetectable, whereas Tc sorption in the cementitious materials containing slag continues to increase with contact time (measured after 1, 4, 8, 19 and 56 days). Sorption was not consistent with spike concentrations and steady state has not been demonstrated after 56 days. The average conditional K{sub d} value for the Vault 2 cementitious material was 873 mL/g (17% slag), for the TR547 Saltstone (45% slag) the conditional K{sub d} was 168 mL/g, and for TR545 (90% slag) the conditional K{sub d} was 1,619 mL/g. It is anticipated that additional samples will be collected until steady state conditions are established to permit measuring more representative K{sub d} and solubility values under these experimental conditions. The purpose of this revision is to correct K{sub d} values reported in the original document. This document reports results for the first 56 days of a 319 day experiment. After the experiment had finished and all the data were compiled for QA/QC analysis, a mistake in the K{sub d} calculations was found. The K{sub d} values reported in revision 0 of this report were essentially one order of magnitude higher than the actual values. In this revision, the text references to K{sub d} values have been updated along with the data in Figure 2 and Appendix B. Between the time the original document was issued, Janurary 2012, and this document was issued, a final report (Estes et al. 2012; SRNL-STI-2012-00596, Rev. 0) describing all the corrected data for the 319 day experiment was issued. This document does not contain any data that is not already reported in the final report (SRNL-STI-2012-00596, Rev. 0).« less

EVALUATION OF REQUIREMENTS FOR THE DWPF HIGHER CAPACITY CANISTER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, D.; Estochen, E.; Jordan, J.

2014-08-05

The Defense Waste Processing Facility (DWPF) is considering the option to increase canister glass capacity by reducing the wall thickness of the current production canister. This design has been designated as the DWPF Higher Capacity Canister (HCC). A significant decrease in the number of canisters processed during the life of the facility would be achieved if the HCC were implemented leading to a reduced overall reduction in life cycle costs. Prior to implementation of the change, Savannah River National Laboratory (SRNL) was requested to conduct an evaluation of the potential impacts. The specific areas of interest included loading and deformationmore » of the canister during the filling process. Additionally, the effect of the reduced wall thickness on corrosion and material compatibility needed to be addressed. Finally the integrity of the canister during decontamination and other handling steps needed to be determined. The initial request regarding canister fabrication was later addressed in an alternate study. A preliminary review of canister requirements and previous testing was conducted prior to determining the testing approach. Thermal and stress models were developed to predict the forces on the canister during the pouring and cooling process. The thermal model shows the HCC increasing and decreasing in temperature at a slightly faster rate than the original. The HCC is shown to have a 3°F ΔT between the internal and outer surfaces versus a 5°F ΔT for the original design. The stress model indicates strain values ranging from 1.9% to 2.9% for the standard canister and 2.5% to 3.1% for the HCC. These values are dependent on the glass level relative to the thickness transition between the top head and the canister wall. This information, along with field readings, was used to set up environmental test conditions for corrosion studies. Small 304-L canisters were filled with glass and subjected to accelerated environmental testing for 3 months. No evidence of stress corrosion cracking was indicated on either the canisters or U-bend coupons. Calculations and finite element modeling were used to determine forces over a range of handling conditions along with possible forces during decontamination. While expected reductions in some physical characteristics were found in the HCC, none were found to be significant when compared to the required values necessary to perform its intended function. Based on this study and a review of successful testing of thinner canisters at West Valley Demonstration Project (WVDP), the mechanical properties obtained with the thinner wall do not significantly undermine the ability of the canister to perform its intended function.« less

Modeling and simulation of large scale stirred tank

NASA Astrophysics Data System (ADS)

Neuville, John R.

The purpose of this dissertation is to provide a written record of the evaluation performed on the DWPF mixing process by the construction of numerical models that resemble the geometry of this process. There were seven numerical models constructed to evaluate the DWPF mixing process and four pilot plants. The models were developed with Fluent software and the results from these models were used to evaluate the structure of the flow field and the power demand of the agitator. The results from the numerical models were compared with empirical data collected from these pilot plants that had been operated at an earlier date. Mixing is commonly used in a variety ways throughout industry to blend miscible liquids, disperse gas through liquid, form emulsions, promote heat transfer and, suspend solid particles. The DOE Sites at Hanford in Richland Washington, West Valley in New York, and Savannah River Site in Aiken South Carolina have developed a process that immobilizes highly radioactive liquid waste. The radioactive liquid waste at DWPF is an opaque sludge that is mixed in a stirred tank with glass frit particles and water to form slurry of specified proportions. The DWPF mixing process is composed of a flat bottom cylindrical mixing vessel with a centrally located helical coil, and agitator. The helical coil is used to heat and cool the contents of the tank and can improve flow circulation. The agitator shaft has two impellers; a radial blade and a hydrofoil blade. The hydrofoil is used to circulate the mixture between the top region and bottom region of the tank. The radial blade sweeps the bottom of the tank and pushes the fluid in the outward radial direction. The full scale vessel contains about 9500 gallons of slurry with flow behavior characterized as a Bingham Plastic. Particles in the mixture have an abrasive characteristic that cause excessive erosion to internal vessel components at higher impeller speeds. The desire for this mixing process is to ensure the agitation of the vessel is adequate to produce a homogenous mixture but not so high that it produces excessive erosion to internal components. The main findings reported by this study were: (1) Careful consideration of the fluid yield stress characteristic is required to make predictions of fluid flow behavior. Laminar Models can predict flow patterns and stagnant regions in the tank until full movement of the flow field occurs. Power Curves and flow patterns were developed for the full scale mixing model to show the differences in expected performance of the mixing process for a broad range of fluids that exhibit Herschel--Bulkley and Bingham Plastic flow behavior. (2) The impeller power demand is independent of the flow model selection for turbulent flow fields in the region of the impeller. The laminar models slightly over predicted the agitator impeller power demand produced by turbulent models. (3) The CFD results show that the power number produced by the mixing system is independent of size. The 40 gallon model produced the same power number results as the 9300 gallon model for the same process conditions. (4) CFD Results show that the Scale-Up of fluid motion in a 40 gallon tank should compare with fluid motion at full scale, 9300 gallons by maintaining constant impeller Tip Speed.

Organics Characterization Of DWPF Alternative Reductant Simulants, Glycolic Acid, And Antifoam 747

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, T. L.; Wiedenman, B. J.; Lambert, D. P.

The present study examines the fate of glycolic acid and other organics added in the Chemical Processing Cell (CPC) of the Defense Waste Processing Facility (DWPF) as part of the glycolic alternate flowsheet. Adoption of this flowsheet is expected to provide certain benefits in terms of a reduction in the processing time, a decrease in hydrogen generation, simplification of chemical storage and handling issues, and an improvement in the processing characteristics of the waste stream including an increase in the amount of nitrate allowed in the CPC process. Understanding the fate of organics in this flowsheet is imperative because tankmore » farm waste processed in the CPC is eventually immobilized by vitrification; thus, the type and amount of organics present in the melter feed may affect optimal melt processing and the quality of the final glass product as well as alter flammability calculations on the DWPF melter off gas. To evaluate the fate of the organic compounds added as the part of the glycolic flowsheet, mainly glycolic acid and antifoam 747, samples of simulated waste that was processed using the DWPF CPC protocol for tank farm sludge feed were generated and analyzed for organic compounds using a variety of analytical techniques at the Savannah River National Laboratory (SRNL). These techniques included Ion Chromatography (IC), Gas Chromatography-Mass Spectrometry (GC-MS), Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES), and Nuclear Magnetic Resonance (NMR) Spectroscopy. A set of samples were also sent to the Catholic University of America Vitreous State Laboratory (VSL) for analysis by NMR Spectroscopy at the University of Maryland, College Park. Analytical methods developed and executed at SRNL collectively showed that glycolic acid was the most prevalent organic compound in the supernatants of Slurry Mix Evaporator (SME) products examined. Furthermore, the studies suggested that commercially available glycolic acid contained minor amounts of impurities such as formic and diglycolic acid that were then carried over in the SME products. Oxalic acid present in the simulated tank farm waste was also detected. Finally, numerous other compounds, at low concentrations, were observed present in etheric extracts of aqueous supernate solutions of the SME samples and are thought to be breakdown products of antifoam 747. The data collectively suggest that although addition of glycolic acid and antifoam 747 will introduce a number of impurities and breakdown products into the melter feed, the concentrations of these organics is expected to remain low and may not significantly impact REDOX or off-gas flammability predictions. In the SME products examined presently, which contained variant amounts of glycolic acid and antifoam 747, no unexpected organic degradation product was found at concentrations above 500 mg/kg, a reasonable threshold concentration for an organic compound to be taken into account in the REDOX modeling. This statement does not include oxalic or formic acid that were sometimes observed above 500 mg/kg and acetic acid that has an analytical detection limit of 1250 mg/kg due to high glycolate concentration in the SME products tested. Once a finalized REDOX equation has been developed and implemented, REDOX properties of known organic species will be determined and their impact assessed. Although no immediate concerns arose during the study in terms of a negative impact of organics present in SME products of the glycolic flowsheet, evidence of antifoam degradation suggest that an alternative antifoam to antifoam 747 is worth considering. The determination and implementation of an antifoam that is more hydrolysis resistant would have benefits such as increasing its effectiveness over time and reducing the generation of degradation products.« less

Rheological Characterization of Unusual DWPF Slurry Samples (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopman, D. C.

2005-09-01

A study was undertaken to identify and clarify examples of unusual rheological behavior in Defense Waste Processing Facility (DWPF) simulant slurry samples. Identification was accomplished by reviewing sludge, Sludge Receipt and Adjustment Tank (SRAT) product, and Slurry Mix Evaporator (SME) product simulant rheological results from the prior year. Clarification of unusual rheological behavior was achieved by developing and implementing new measurement techniques. Development of these new methods is covered in a separate report, WSRC-TR-2004-00334. This report includes a review of recent literature on unusual rheological behavior, followed by a summary of the rheological measurement results obtained on a set ofmore » unusual simulant samples. Shifts in rheological behavior of slurries as the wt. % total solids changed have been observed in numerous systems. The main finding of the experimental work was that the various unusual DWPF simulant slurry samples exhibit some degree of time dependent behavior. When a given shear rate is applied to a sample, the apparent viscosity of the slurry changes with time rather than remaining constant. These unusual simulant samples are more rheologically complex than Newtonian liquids or more simple slurries, neither of which shows significant time dependence. The study concludes that the unusual rheological behavior that has been observed is being caused by time dependent rheological properties in the slurries being measured. Most of the changes are due to the effect of time under shear, but SB3 SME products were also changing properties while stored in sample bottles. The most likely source of this shear-related time dependence for sludge is in the simulant preparation. More than a single source of time dependence was inferred for the simulant SME product slurries based on the range of phenomena observed. Rheological property changes were observed on the time-scale of a single measurement (minutes) as well as on a time scale of hours to weeks. The unusual shape of the slurry flow curves was not an artifact of the rheometric measurement. Adjusting the user-specified parameters in the rheometer measurement jobs can alter the shape of the flow curve of these time dependent samples, but this was not causing the unusual behavior. Variations in the measurement parameters caused the time dependence of a given slurry to manifest at different rates. The premise of the controlled shear rate flow curve measurement is that the dynamic response of the sample to a change in shear rate is nearly instantaneous. When this is the case, the data can be fitted to a time independent rheological equation, such as the Bingham plastic model. In those cases where this does not happen, interpretation of the data is difficult. Fitting time dependent data to time independent rheological equations, such as the Bingham plastic model, is also not appropriate.« less

Results Of Hg Speciation Testing On DWPF SMECT-1, SMECT-3, And SMECT-5 Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C.

2016-01-07

The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team. The thirteenth shipment of samples was designated to include Defense Waste Processing Facility (DWPF) Slurry Mix Evaporator Condensate Tank (SMECT) from Sludge Receipt and Adjustment Tank (SRAT) Batch 736 and 738 samples. Triplicate samples of each material were prepared for this shipment. Each replicate was analyzed for seven Hg species: total Hg, total soluble (dissolved) Hg, elemental Hg [Hg(0)], ionic (inorganic) Hg [Hg(I) andmore » Hg(II)], methyl Hg [CH 3Hg-X, where X is a counter anion], ethyl Hg [CH 3CH 2-Hg-X, where X is a counter anion], and dimethyl Hg [(CH 3) 2Hg]. The difference between the total Hg and total soluble Hg measurements gives the particulate Hg concentration, i.e. Hg adsorbed to the surface of particulate matter in the sample but without resolution of the specific adsorbed species. The average concentrations of Hg species in the aqueous samples derived from Eurofins reported data corrected for dilutions performed by SRNL are tabulated.« less

DWPF Melt Cell Crawler

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, C.R.

2003-04-08

On December 2, 2002, Remote and Specialty Equipment Systems (RSES) of the Savannah River Technology Center (SRTC) was requested to build a remotely operated crawler to assist in cleaning the Defense Waste Processing Facility (DWPF) melt cell floor of glass, tools, and other debris. The crawler was to assist a grapple and vacuum system in cleaning the cell. The crawler was designed to push glass and debris into piles so that the grapple could pick up the material and place it in waste bins. The crawler was also designed to maneuver the end of the vacuum hose, if needed. Inmore » addition, the crawler was designed to clean the area beneath the cell worktable that was inaccessible to the grapple and vacuum system. Originally, the system was to be ready for deployment by December 17. The date was moved up to December 12 to better utilize the available time for clean up. The crawler was designed and built in 10 days and completed cleaning the melt cell in 8 days. Due to initial problems with the grapple and vacuum system, the crawler completed essentially all of the cleanup tasks by itself. The crawler also cleaned an area on the west side of the cell that was not initially slated for cleaning.« less

Yield Stress Reduction of DWPF Melter Feed Slurries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M.E.; Smith, M.E.

2007-07-01

The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies High Level Waste for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. The HLW consists of insoluble metal hydroxides and soluble sodium salts. The pretreatment process acidifies the sludge with nitric and formic acids, adds the glass formers as glass frit, then concentrates the resulting slurry to approximately 50 weight percent (wt%) total solids. This slurry is fed to the joule-heated melter where the remaining water is evaporated followed by calcination of the solids and conversion to glass. The Savannah Rivermore » National Laboratory (SRNL) is currently assisting DWPF efforts to increase throughput of the melter. As part of this effort, SRNL has investigated methods to increase the solids content of the melter feed to reduce the heat load required to complete the evaporation of water and allow more of the energy available to calcine and vitrify the waste. The process equipment in the facility is fixed and cannot process materials with high yield stresses, therefore increasing the solids content will require that the yield stress of the melter feed slurries be reduced. Changing the glass former added during pretreatment from an irregularly shaped glass frit to nearly spherical beads was evaluated. The evaluation required a systems approach which included evaluations of the effectiveness of beads in reducing the melter feed yield stress as well as evaluations of the processing impacts of changing the frit morphology. Processing impacts of beads include changing the settling rate of the glass former (which effects mixing and sampling of the melter feed slurry and the frit addition equipment) as well as impacts on the melt behavior due to decreased surface area of the beads versus frit. Beads were produced from the DWPF process frit by fire polishing. The frit was allowed to free fall through a flame, then quenched with a water spray. Approximately 90% of the frit was converted to beads by this process. Yield stress reduction was measured by preparing melter feed slurries (using nonradioactive HLW simulants) that contain beads and comparing the yield stress with melter feed containing frit. A second set of tests was performed with beads of various diameters to determine if a decrease in diameter affected the results. Smaller particle size was shown to increase yield stress when frit is utilized. The settling rate of the beads was required to match the settling rate of the frit, therefore a decrease in particle size was anticipated. Settling tests were conducted in water, xanthan gum solutions, and in non-radioactive simulants of the HLW. The tests used time-lapse video-graphy as well as solids sampling to evaluate the settling characteristics of beads compared to frit of the same particle size. A preliminary melt rate evaluation was performed using a dry-fed Melt Rate Furnace (MRF) developed by SRNL. Preliminary evaluation of the impact of beading the frit on the frit addition system were completed by conducting flow loop testing. A recirculation loop was built with a total length of about 30 feet. Pump power, flow rate, outlet pressure, and observations of the flow in the horizontal upper section of the loop were noted. The recirculation flow was then gradually reduced and the above items recorded until settling was noted in the recirculation line. Overall, the data shows that the line pressure increased as the solids were increased for the same flow rate. In addition, the line pressure was higher for Frit 320 than the beads at the same solids level and flow. With the observations, a determination of minimum velocity to prevent settling could be done, but a graph of the line pressures versus velocity for the various tests was deemed to more objective. The graph shows that the inflection point in pressure drop is about the same for the beads and Frit 320. This indicates that the bead slurry would not require higher flows rates than frit slurry at DWPF during transfers. Another key finding was that the pump impeller was not significantly damaged by the bead slurry, while the Frit 320 slurry rapidly destroyed the impeller. Evidence of this was first observed when black particles were seen in the Frit 320 slurry being recirculated and then confirmed by a post-test inspection of the impeller. Finally, the pumping of bead slurry could be recovered even if flow is stopped. The Frit 320 slurry could not be restarted after stopping flow due to the nature of the frit to pack tightly when settled. Beads were shown to represent a significant process improvement versus frit for the DWPF process in lowering yield stress of the melter feed. Lower erosion of process equipment is another expected benefit.« less

Implementation of flowsheet change to minimize hydrogen and ammonia generation during chemical processing of high level waste in the Defense Waste Processing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, Dan P.; Woodham, Wesley H.; Williams, Matthew S.

Testing was completed to develop a chemical processing flowsheet for the Defense Waste Processing Facility (DWPF), designed to vitrify and stabilize high level radioactive waste. DWPF processing uses a reducing acid (formic acid) and an oxidizing acid (nitric acid) to rheologically thin the slurry and complete the necessary acid base and reduction reactions (primarily mercury and manganese). Formic acid reduces mercuric oxide to elemental mercury, allowing the mercury to be removed during the boiling phase of processing through steam stripping. In runs with active catalysts, formic acid can decompose to hydrogen and nitrate can be reduced to ammonia, both flammablemore » gases, due to rhodium and ruthenium catalysis. Replacement of formic acid with glycolic acid eliminates the generation of rhodium- and ruthenium-catalyzed hydrogen and ammonia. In addition, mercury reduction is still effective with glycolic acid. Hydrogen, ammonia and mercury are discussed in the body of the report. Ten abbreviated tests were completed to develop the operating window for implementation of the flowsheet and determine the impact of changes in acid stoichiometry and the blend of nitric and glycolic acid as it impacts various processing variables over a wide processing region. Three full-length 4-L lab-scale simulations demonstrated the viability of the flowsheet under planned operating conditions. The flowsheet is planned for implementation in early 2017.« less

Sludge batch 9 (SB9) acceptance evaluation. Radionuclide concentrations in tank 51 SB9 qualification sample prepared at SRNL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.; Diprete, D. P.; Pareizs, J. M.

Presented in this report are radionuclide concentrations required as part of the program of qualifying Sludge Batch 9 (SB9) for processing in the Defense Waste Processing Facility (DWPF). The SB9 material is currently in Tank 51 and has been washed and prepared for transfer to Tank 40. The acceptance evaluation needs to be completed prior to the transfer of the material in Tank 51 to Tank 40. The sludge slurry in Tank 40 has already been qualified for DWPF processing and is currently being processed as Sludge Batch 8 (SB8). The radionuclide concentrations were measured or estimated in the Tankmore » 51 SB9 Washed Qualification Sample prepared at Savannah River National Laboratory (SRNL). This sample was prepared from a three liter sample of Tank 51 sludge slurry (HTF-51-15-81) taken on July 23, 2015. The sample was delivered to SRNL where it was initially characterized in the Shielded Cells. Under the direction of Savannah River Remediation (SRR) it was then adjusted per the Tank Farm washing strategy as of October 20, 2015. This final slurry now has a composition expected to be similar to that of the slurry in Tank 51 after final preparations have been made for transfer of that slurry to Tank 40.« less

Sludge batch 9 (SB9) accepance evaluation: Radionuclide concentrations in tank 51 SB9 qualification sample prepared at SRNL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C.; Diprete, D.; Pareizs, J.

Presented in this report are radionuclide concentrations required as part of the program of qualifying Sludge Batch 9 (SB9) for processing in the Defense Waste Processing Facility (DWPF). The SB9 material is currently in Tank 51 and has been washed and prepared for transfer to Tank 40. The acceptance evaluation needs to be completed prior to the transfer of the material in Tank 51 to Tank 40. The sludge slurry in Tank 40 has already been qualified for DWPF processing and is currently being processed as Sludge Batch 8 (SB8). The radionuclide concentrations were measured or estimated in the Tankmore » 51 SB9 Washed Qualification Sample prepared at Savannah River National Laboratory (SRNL). This sample was prepared from a three liter sample of Tank 51 sludge slurry (HTF-51-15-81) taken on July 23, 2015. The sample was delivered to SRNL where it was initially characterized in the Shielded Cells. Under the direction of Savannah River Remediation (SRR) it was then adjusted per the Tank Farm washing strategy as of October 20, 2015. This final slurry now has a compositioniv expected to be similar to that of the slurry in Tank 51 after final preparations have been made for transfer of that slurry to Tank 40.« less

LITERATURE REVIEW ON IMPACT OF GLYCOLATE ON THE 2H EVAPORATOR AND THE EFFLUENT TREATMENT FACILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adu-Wusu, K.

2012-05-10

Glycolic acid (GA) is being studied as an alternate reductant in the Defense Waste Processing Facility (DWPF) feed preparation process. It will either be a total or partial replacement for the formic acid that is currently used. A literature review has been conducted on the impact of glycolate on two post-DWPF downstream systems - the 2H Evaporator system and the Effluent Treatment Facility (ETF). The DWPF recycle stream serves as a portion of the feed to the 2H Evaporator. Glycolate enters the evaporator system from the glycolate in the recycle stream. The overhead (i.e., condensed phase) from the 2H Evaporatormore » serves as a portion of the feed to the ETF. The literature search revealed that virtually no impact is anticipated for the 2H Evaporator. Glycolate may help reduce scale formation in the evaporator due to its high complexing ability. The drawback of the solubilizing ability is the potential impact on the criticality analysis of the 2H Evaporator system. It is recommended that at least a theoretical evaluation to confirm the finding that no self-propagating violent reactions with nitrate/nitrites will occur should be performed. Similarly, identification of sources of ignition relevant to glycolate and/or update of the composite flammability analysis to reflect the effects from the glycolate additions for the 2H Evaporator system are in order. An evaluation of the 2H Evaporator criticality analysis is also needed. A determination of the amount or fraction of the glycolate in the evaporator overhead is critical to more accurately assess its impact on the ETF. Hence, use of predictive models like OLI Environmental Simulation Package Software (OLI/ESP) and/or testing are recommended for the determination of the glycolate concentration in the overhead. The impact on the ETF depends on the concentration of glycolate in the ETF feed. The impact is classified as minor for feed glycolate concentrations {le} 33 mg/L or 0.44 mM. The ETF unit operations that will have minor/major impacts are chlorination, pH adjustment, 1st mercury removal, organics removal, 2nd mercury removal, and ion exchange. For minor impacts, the general approach is to use historical process operations data/modeling software like OLI/ESP and/or monitoring/compiled process operations data to resolve any uncertainties with testing as a last resort. For major impacts (i.e., glycolate concentrations > 33 mg/L or 0.44 mM), testing is recommended. No impact is envisaged for the following ETF unit operations regardless of the glycolate concentration - filtration, reverse osmosis, ion exchange resin regeneration, and evaporation.« less

SLUDGE BATCH 4 BASELINE MELT RATE FURNACE AND SLURRY-FED MELT RATE FURNACE TESTS WITH FRITS 418 AND 510 (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, M. E.; Jones, T. M.; Miller, D. H.

Several Slurry-Fed Melt Rate Furnace (SMRF) tests with earlier projections of the Sludge Batch 4 (SB4) composition have been performed.1,2 The first SB4 SMRF test used Frits 418 and 320, however it was found after the test that the REDuction/OXidation (REDOX) correlation at that time did not have the proper oxidation state for manganese. Because the manganese level in the SB4 sludge was higher than previous sludge batches tested, the impact of the higher manganese oxidation state was greater. The glasses were highly oxidized and very foamy, and therefore the results were inconclusive. After resolving this REDOX issue, Frits 418,more » 425, and 503 were tested in the SMRF with the updated baseline SB4 projection. Based on dry-fed Melt Rate Furnace (MRF) tests and the above mentioned SMRF tests, two previous frit recommendations were made by the Savannah River National Laboratory (SRNL) for processing of SB4 in the Defense Waste Processing Facility (DWPF). The first was Frit 503 based on the June 2006 composition projections.3 The recommendation was changed to Frit 418 as a result of the October 2006 composition projections (after the Tank 40 decant was implemented as part of the preparation plan). However, the start of SB4 processing was delayed due to the control room consolidation outage and the repair of the valve box in the Tank 51 to Tank 40 transfer line. These delays resulted in changes to the projected SB4 composition. Due to the slight change in composition and based on preliminary dry-fed MRF testing, SRNL believed that Frit 510 would increase throughput in processing SB4 in DWPF. Frit 418, which was used in processing Sludge Batch 3 (SB3), was a viable candidate and available in DWPF. Therefore, it was used during the initial SB4 processing. Due to the potential for higher melt rates with Frit 510, SMRF tests with the latest SB4 composition (1298 canisters) and Frits 510 and 418 were performed at a targeted waste loading (WL) of 35%. The '1298 canisters' describes the number of equivalent canisters that would be produced from the beginning of the current contract period before SB3 is blended with SB4. The melt rate for the SMRF SB4/Frit 510 test was 14.6 grams/minute. Due to cold cap mounding problems with the SMRF SB4/Frit 418 feed at 50 weight % solids that prevented a melt rate determination, this feed was diluted to 45 weight % solids. The melt rate for this diluted feed was 8.9 grams/minute. A correction factor of 1.2 for estimating the melt rate at 50 weight % solids from 45 weight % solids test results (based on previous SMRF testing5) was then used to estimate a melt rate of 10.7 grams/minute for SB4/Frit 418 at 50 weight % solids. Therefore, the use of Frit 510 versus Frit 418 with SB4 resulted in a higher melt rate (14.6 versus an estimated 10.7 grams/minute). For reference, a previous SMRF test with SB3/Frit 418 feed at 35% waste loading and 50 weight % solids resulted in a melt rate of 14.1 grams/minute. Therefore, depending on the actual feed rheology, the use of Frit 510 with SB4 could result in similar melt rates as experienced with SB3/Frit 418 feed in the DWPF.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Newell, J; Miller, D; Stone, M

The Savannah River National Laboratory (SRNL) was tasked to provide an assessment of the downstream impacts to the Defense Waste Processing Facility (DWPF) of decisions regarding the implementation of Al-dissolution to support sludge mass reduction and processing. Based on future sludge batch compositional projections from the Liquid Waste Organization's (LWO) sludge batch plan, assessments have been made with respect to the ability to maintain comparable projected operating windows for sludges with and without Al-dissolution. As part of that previous assessment, candidate frits were identified to provide insight into melt rate for average sludge batches representing with and without Al-dissolution flowsheets.more » Initial melt rate studies using the melt rate furnace (MRF) were performed using five frits each for Cluster 2 and Cluster 4 compositions representing average without and with Al-dissolution. It was determined, however, that the REDOX endpoint (Fe{sup 2+}/{Sigma}Fe for the glass) for Clusters 2 and 4 resulted in an overly oxidized feed which negatively affected the initial melt rate tests. After the sludge was adjusted to a more reduced state, additional testing was performed with frits that contained both high and low concentrations of sodium and boron oxides. These frits were selected strictly based on the ability to ascertain compositional trends in melt rate and did not necessarily apply to any acceptability criteria for DWPF processing. The melt rate data are in general agreement with historical trends observed at SRNL and during processing of SB3 (Sludge Batch 3)and SB4 in DWPF. When MAR acceptability criteria were applied, Frit 510 was seen to have the highest melt rate at 0.67 in/hr for Cluster 2 (without Al-dissolution), which is compositionally similar to SB4. For Cluster 4 (with Al-dissolution), which is compositionally similar to SB3, Frit 418 had the highest melt rate at 0.63 in/hr. Based on this data, there appears to be a slight advantage of the Frit 510 based system without Al-dissolution relative to the Frit 418 based system with Al-dissolution. Though the without aluminum dissolution scenario suggests a slightly higher melt rate with frit 510, several points must be taken into consideration: (1) The MRF does not have the ability to assess liquid feeds and, thus, rheology impacts. Instead, the MRF is a 'static' test bed in which a mass of dried melter feed (SRAT product plus frit) is placed in an 'isothermal' furnace for a period of time to assess melt rate. These conditions, although historically effective in terms of identifying candidate frits for specific sludge batches and mapping out melt rate versus waste loading trends, do not allow for assessments of the potential impact of feed rheology on melt rate. That is, if the rheological properties of the slurried melter feed resulted in the mounding of the feed in the melter (i.e., the melter feed was thick and did not flow across the cold cap), melt rate and/or melter operations (i.e., surges) could be negatively impacted. This could affect one or both flowsheets. (2) Waste throughput factors were not determined for Frit 510 and Frit 418 over multiple waste loadings. In order to provide insight into the mission life versus canister count question, one needs to define the maximum waste throughput for both flowsheets. Due to funding limitations, the melt rate testing only evaluated melt rate at a fixed waste loading. (3) DWPF will be processing SB5 through their facility in mid-November 2008. Insight into the over arching questions of melt rate, waste throughput, and mission life can be obtained directly from the facility. It is recommended that processing of SB5 through the facility be monitored closely and that data be used as input into the decision making process on whether to implement Al-dissolution for future sludge batches.« less

Road Map for Development of Crystal-Tolerant High Level Waste Glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matyas, Josef; Vienna, John D.; Peeler, David

This road map guides the research and development for formulation and processing of crystal-tolerant glasses, identifying near- and long-term activities that need to be completed over the period from 2014 to 2019. The primary objective is to maximize waste loading for Hanford waste glasses without jeopardizing melter operation by crystal accumulation in the melter or melter discharge riser. The potential applicability to the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF) is also addressed in this road map.

Review of Concrete Biodeterioration in Relation to Buried Nuclear Waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turick, C; Berry, C.

Long-term storage of low level radioactive material in below ground concrete disposal units (DUs) (Saltstone Disposal Facility) is a means of depositing wastes generated from nuclear operations of the U.S. Department of Energy. Based on the currently modeled degradation mechanisms, possible microbial induced effects on the structural integrity of buried low level wastes must be addressed. Previous international efforts related to microbial impacts on concrete structures that house low level radioactive waste showed that microbial activity can play a significant role in the process of concrete degradation and ultimately structural deterioration. This literature review examines the recent research in thismore » field and is focused on specific parameters that are applicable to modeling and prediction of the fate of concrete vaults housing stored wastes and the wastes themselves. Rates of concrete biodegradation vary with the environmental conditions, illustrating a need to understand the bioavailability of key compounds involved in microbial activity. Specific parameters require pH and osmotic pressure to be within a certain range to allow for microbial growth as well as the availability and abundance of energy sources like components involved in sulfur, iron and nitrogen oxidation. Carbon flow and availability are also factors to consider in predicting concrete biodegradation. The results of this review suggest that microbial activity in Saltstone, (grouted low level radioactive waste) is unlikely due to very high pH and osmotic pressure. Biodegradation of the concrete vaults housing the radioactive waste however, is a possibility. The rate and degree of concrete biodegradation is dependent on numerous physical, chemical and biological parameters. Results from this review point to parameters to focus on for modeling activities and also, possible options for mitigation that would minimize concrete biodegradation. In addition, key chemical components that drive microbial activity on concrete surfaces are discussed.« less

Performance Assessment Program for the Savannah River Site Liquid Waste Facilities - 13610

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosenberger, Kent H.

2013-07-01

The Liquid Waste facilities at the U.S. Department of Energy's (DOE) Savannah River Site (SRS) are operated by Liquid Waste Operations contractor Savannah River Remediation LLC (SRR). A separate Performance Assessment (PA) is prepared to support disposal operations at the Saltstone Disposal Facility and closure evaluations for the two liquid waste tank farm facilities at SRS, F-Tank Farm and H-Tank Farm. A PA provides the technical basis and results to be used in subsequent documents to demonstrate compliance with the pertinent requirements identified in operations and closure regulatory guidance. The Saltstone Disposal Facility is subject to a State of Southmore » Carolina industrial solid waste landfill permit and the tank farms are subject to a state industrial waste water permit. The three Liquid Waste facilities are also subject to a Federal Facility Agreement approved by the State, DOE and the Environmental Protection Agency (EPA). Due to the regulatory structure, a PA is a key technical document reviewed by the DOE, the State of South Carolina and the EPA. As the waste material disposed of in the Saltstone Disposal Facility and the residual material in the closed tank farms is also subject to reclassification prior to closure via a waste determination pursuant to Section 3116 of the Ronald W. Reagan National Defense Authorization Act of Fiscal Year 2005, the U.S. Nuclear Regulatory Commission (NRC) is also a reviewing agency for the PAs. Pursuant to the Act, the NRC also has a continuing role to monitor disposal actions to assess compliance with stated performance objectives. The Liquid Waste PA program at SRS represents a continual process over the life of the disposal and closure operations. When the need for a PA or PA revision is identified, the first step is to develop a conceptual model to best represent the facility conditions. The conceptual model will include physical dimensions of the closed system, both the engineered and natural system, and modeling input parameters associated with the modeled features, both initial values (at the time of facility closure) and degradation rates/values. During the development of the PA, evaluations are conducted to reflect not only the results associated with the best available information at the time but also to evaluate potential uncertainties and sensitivities associated with the modeled system. While the PA will reflect the modeled system results from the best available information, it will also identify areas for future work to reduce overall PA uncertainties moving forward. DOE requires a PA Maintenance Program such that work continues to reduce model uncertainties, thus bolstering confidence in PA results that support regulatory decisions. This maintenance work may include new Research and Development activities or modeling as informed by previous PA results and other new information that becomes available. As new information becomes available, it is evaluated against previous PAs and appropriate actions are taken to ensure continued confidence in the regulatory decisions. Therefore, the PA program is a continual process that is not just the development of a PA but seeks to incorporate new information to reduce overall model uncertainty and provide continuing confidence in regulatory decisions. (author)« less

Actual Waste Demonstration of the Nitric-Glycolic Flowsheet for Sludge Batch 9 Qualification

DOE Office of Scientific and Technical Information (OSTI.GOV)

J. D. Newell; Pareizs, J. M.; Martino, C. J.

For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) performs qualification testing to demonstrate that the sludge batch is processable. Testing performed by the Savannah River National Laboratory has shown glycolic acid to be effective in replacing the function of formic acid in the DWPF chemical process. The nitric-glycolic flowsheet reduces mercury, significantly lowers the catalytic generation of hydrogen and ammonia which could allow purge reduction in the Sludge Receipt and Adjustment Tank (SRAT), stabilizes the pH and chemistry in the SRAT and the Slurry Mix Evaporator (SME), allowsmore » for effective rheology adjustment, and is favorable with respect to melter flammability. In order to implement the new flowsheet, SRAT and SME cycles, designated SC-18, were performed using a Sludge Batch (SB) 9 slurry blended from SB8 Tank 40H and Tank 51H samples. The SRAT cycle involved adding nitric and glycolic acids to the sludge, refluxing to steam strip mercury, and dewatering to a targeted solids concentration. Data collected during the SRAT cycle included offgas analyses, process temperatures, heat transfer, and pH measurements. The SME cycle demonstrated the addition of glass frit and the replication of six canister decontamination additions. The demonstration concluded with dewatering to a targeted solids concentration. Data collected during the SME cycle included offgas analyses, process temperatures, heat transfer, and pH measurements. Slurry and condensate samples were collected for subsequent analysis« less

Alternate Reductant Cold Cap Evaluation Furnace Phase II Testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, F. C.; Stone, M. E.; Miller, D. H.

2014-09-03

Savannah River Remediation (SRR) conducted a Systems Engineering Evaluation (SEE) to determine the optimum alternate reductant flowsheet for the Defense Waste Processing Facility (DWPF). Specifically, two proposed flowsheets (nitric–formic–glycolic and nitric–formic–sugar) were evaluated based upon results from preliminary testing. Comparison of the two flowsheets among evaluation criteria indicated a preference towards the nitric–formic–glycolic flowsheet. Further research and development of this flowsheet eliminated the formic acid, and as a result, the nitric–glycolic flowsheet was recommended for further testing. Based on the development of a roadmap for the nitric–glycolic acid flowsheet, Waste Solidification Engineering (WS-E) issued a Technical Task Request (TTR) tomore » address flammability issues that may impact the implementation of this flowsheet. Melter testing was requested in order to define the DWPF flammability envelope for the nitric-glycolic acid flowsheet. The Savannah River National Laboratory (SRNL) Cold Cap Evaluation Furnace (CEF), a 1/12 th scale DWPF melter, was selected by the SRR Alternate Reductant project team as the melter platform for this testing. The overall scope was divided into the following sub-tasks as discussed in the Task Technical and Quality Assurance Plan (TTQAP): Phase I - A nitric–formic acid flowsheet melter test (unbubbled) to baseline the CEF cold cap and vapor space data to the benchmark melter flammability models; Phase II - A nitric–glycolic acid flowsheet melter test (unbubbled and bubbled) to: Define new cold cap reactions and global kinetic parameters in support of the melter flammability model development; Quantify off-gas surging potential of the feed; Characterize off-gas condensate for complete organic and inorganic carbon species. After charging the CEF with cullet from Phase I CEF testing, the melter was slurry-fed with glycolic flowsheet based SB6-Frit 418 melter feed at 36% waste loading and was operated continuously for 25 days. Process data was collected throughout testing and included melter operation parameters and off-gas chemistry. In order to generate off-gas data in support of the flammability model development for the nitric-glycolic flowsheet, vapor space steady state testing in the range of ~300-750°C was conducted under the following conditions, (i) 100% (nominal and excess antifoam levels) and 125% stoichiometry feed and (ii) with and without argon bubbling. Adjustments to feed rate, heater outputs and purge air flow were necessary in order to achieve vapor space temperatures in this range. Surge testing was also completed under nominal conditions for four days with argon bubbling and one day without argon bubbling.« less

IMPACTS OF ANTIFOAM ADDITIONS AND ARGON BUBBLING ON DEFENSE WASTE PROCESSING FACILITY REDUCTION/OXIDATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C.; Johnson, F.

2012-06-05

During melting of HLW glass, the REDOX of the melt pool cannot be measured. Therefore, the Fe{sup +2}/{Sigma}Fe ratio in the glass poured from the melter must be related to melter feed organic and oxidant concentrations to ensure production of a high quality glass without impacting production rate (e.g., foaming) or melter life (e.g., metal formation and accumulation). A production facility such as the Defense Waste Processing Facility (DWPF) cannot wait until the melt or waste glass has been made to assess its acceptability, since by then no further changes to the glass composition and acceptability are possible. therefore, themore » acceptability decision is made on the upstream process, rather than on the downstream melt or glass product. That is, it is based on 'feed foward' statistical process control (SPC) rather than statistical quality control (SQC). In SPC, the feed composition to the melter is controlled prior to vitrification. Use of the DWPF REDOX model has controlled the balanjce of feed reductants and oxidants in the Sludge Receipt and Adjustment Tank (SRAT). Once the alkali/alkaline earth salts (both reduced and oxidized) are formed during reflux in the SRAT, the REDOX can only change if (1) additional reductants or oxidants are added to the SRAT, the Slurry Mix Evaporator (SME), or the Melter Feed Tank (MFT) or (2) if the melt pool is bubble dwith an oxidizing gas or sparging gas that imposes a different REDOX target than the chemical balance set during reflux in the SRAT.« less

Defense Waste Processing Facility Canister Closure Weld Current Validation Testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korinko, P. S.; Maxwell, D. N.

Two closure welds on filled Defense Waste Processing Facility (DWPF) canisters failed to be within the acceptance criteria in the DWPF operating procedure SW4-15.80-2.3 (1). In one case, the weld heat setting was inadvertently provided to the canister at the value used for test welds (i.e., 72%) and this oversight produced a weld at a current of nominally 210 kA compared to the operating procedure range (i.e., 82%) of 240 kA to 263 kA. The second weld appeared to experience an instrumentation and data acquisition upset. The current for this weld was reported as 191 kA. Review of the datamore » from the Data Acquisition System (DAS) indicated that three of the four current legs were reading the expected values, approximately 62 kA each, and the fourth leg read zero current. Since there is no feasible way by further examination of the process data to ascertain if this weld was actually welded at either the target current or the lower current, a test plan was executed to provide assurance that these Nonconforming Welds (NCWs) meet the requirements for strength and leak tightness. Acceptance of the welds is based on evaluation of Test Nozzle Welds (TNW) made specifically for comparison. The TNW were nondestructively and destructively evaluated for plug height, heat tint, ultrasonic testing (UT) for bond length and ultrasonic volumetric examination for weld defects, burst pressure, fractography, and metallography. The testing was conducted in agreement with a Task Technical and Quality Assurance Plan (TTQAP) (2) and applicable procedures.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raszewski, F; Tommy Edwards, T; David Peeler, D

The Liquid Waste Organization (LWO) has requested that the Savannah River National Laboratory (SRNL) to assess the impact of a 100K gallon decant volume from Tank 40H on the existing sludge-only Sludge Batch 4 (SB4)-Frit 510 flowsheet and the coupled operations flowsheet (SB4 with the Actinide Removal Process (ARP)). Another potential SB4 flowsheet modification of interest includes the addition of 3 wt% sodium (on a calcined oxide basis) to a decanted sludge-only or coupled operations flowsheet. These potential SB4 flowsheet modifications could result in significant compositional shifts to the SB4 system. This paper study provides an assessment of the impactmore » of these compositional changes to the projected glass operating windows and to the variability study for the Frit 510-SB4 system. The influence of the compositional changes on melt rate was not assessed in this study nor was it requested. Nominal Stage paper study assessments were completed using the projected compositions for the various flowsheet options coupled with Frit 510 (i.e., variation was not applied to the sludge and frit compositions). In order to gain insight into the impacts of sludge variation and/or frit variation (due to the procurement specifications) on the projected operating windows, three versions of the Variation Stage assessment were performed: (1) the traditional Variation Stage assessment in which the nominal Frit 510 composition was coupled with the extreme vertices (EVs) of each sludge, (2) an assessment of the impact of possible frit variation (within the accepted frit specification tolerances) on each nominal SB4 option, and (3) an assessment of the impact of possible variation in the Frit 510 composition due to the vendor's acceptance specifications coupled with the EVs of each sludge case. The results of the Nominal Stage assessment indicate very little difference among the various flowsheet options. All of the flowsheets provide DWPF with the possibility of targeting waste loadings (WLs) from the low 30s to the low 40s with Frit 510. In general, the Tank 40H decant has a slight negative impact on the operating window, but DWPF still has the ability to target current WLs (34%) and higher WLs if needed. While the decant does not affect practical WL targets in DWPF, melt rate could be reduced due to the lower Na{sub 2}O content. If true, the addition of 3 wt% Na{sub 2}O to the glass system may regain melt rate, assuming that the source of alkali is independent of the impact on melt rate. Coupled operations with Frit 510 via the addition of ARP to the decanted SB4 flowsheet also appears to be viable based on the projected operating windows. The addition of both ARP and 3 wt% Na{sub 2}O to a decanted Tank 40H sludge may be problematic using Frit 510. Although the Nominal Stage assessments provide reasonable operating windows for the SB4 flowsheets being considered with Frit 510, introduction of potential sludge and/or frit compositional variation does have a negative impact. The magnitude of the impact on the projected operating windows is dependent on the specific flowsheet options as well as the applied variation. The results of the traditional Variation Stage assessments indicate that the three proposed Tank 40H decanted flowsheet options (Case No.2--100K gallon decant, Case No.3--100K gallon decant and 3 wt% Na{sub 2}O addition and Case No.4--100K gallon decant and ARP) demonstrate a relatively high degree of robustness to possible sludge variation over WLs of interest with Frit 510. However, the case where the addition of both ARP and 3 wt% Na{sub 2}O is considered was problematic during the traditional Variation Stage assessment. The impact of coupling the frit specifications with the nominal SB4 flowsheet options on the projected operating windows is highly dependent on whether the upper WLs are low viscosity or liquidus temperature limited in the Nominal Stage assessments. Systems that are liquidus temperature limited exhibit a high degree of robustness to the applied frit and sludge variation, while those that are low viscosity limited show significant reductions (6 percentage points) in the upper WLs that can be obtained. When both frit and sludge variations are applied, the paper study results indicate that DWPF could be severely restricted in terms of projected operating windows for the ARP and Na{sub 2}O addition options. An experimental variability study was not performed using the final SB4 composition and Frit 510 since glasses in the ComPro{trademark} data base were identified that bounded the potential operating window of this system. The bounding ARP case was not considered in that assessment. After the flowsheet cases were identified, an electronic search of ComPro{trademark} identified approximately 12 historical glasses within the compositional regions defined by at least one of the five flowsheet options, but the compositional coverage did not appear adequate to bound all cases.« less

THE IMPACT OF THE MCU LIFE EXTENSION SOLVENT ON DWPF GLASS FORMULATION EFFORTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D; Edwards, T

2011-03-24

As a part of the Actinide Removal Process (ARP)/Modular Caustic Side Solvent Extraction Unit (MCU) Life Extension Project, a next generation solvent (NG-CSSX), a new strip acid, and modified monosodium titanate (mMST) will be deployed. The strip acid will be changed from dilute nitric acid to dilute boric acid (0.01 M). Because of these changes, experimental testing with the next generation solvent and mMST is required to determine the impact of these changes in 512-S operations as well as Chemical Process Cell (CPC), Defense Waste Processing Facility (DWPF) glass formulation activities, and melter operations at DWPF. To support programmatic objectives,more » the downstream impacts of the boric acid strip effluent (SE) to the glass formulation activities and melter operations are considered in this study. More specifically, the impacts of boric acid additions to the projected SB7b operating windows, potential impacts to frit production temperatures, and the potential impact of boron volatility are evaluated. Although various boric acid molarities have been reported and discussed, the baseline flowsheet used to support this assessment was 0.01M boric acid. The results of the paper study assessment indicate that Frit 418 and Frit 418-7D are robust to the implementation of the 0.01M boric acid SE into the SB7b flowsheet (sludge-only or ARP-added). More specifically, the projected operating windows for the nominal SB7b projections remain essentially constant (i.e., 25-43 or 25-44% waste loading (WL)) regardless of the flowsheet options (sludge-only, ARP added, and/or the presence of the new SE). These results indicate that even if SE is not transferred to the Sludge Receipt and Adjustment Tank (SRAT), there would be no need to add boric acid (from a trim tank) to compositionally compensate for the absence of the boric acid SE in either a sludge-only or ARP-added SB7b flowsheet. With respect to boron volatility, the Measurement Acceptability Region (MAR) assessments also suggest that Slurry Mix Evaporator (SME) acceptability decisions would not be different assuming either 100% of the B{sub 2}O{sub 3} from the SE were retained or volatilized. More specifically, the 0.84 wt% B{sub 2}O{sub 3} in the SE is so minor that its presence in the SME analysis does not influence SME acceptability decisions. In fact, using the 100% retention and 100% volatilization composition projections, only minor differences in the predicted properties of the glass product occur with all of the glasses being acceptable over a WL interval of 32-42%. Based on the 0.01M boric acid flowsheet, there is very little difference between Frit 418 and Frit 418-7D (a frit that was compositionally altered to account for the 0.84 wt% B{sub 2}O{sub 3} in the SE) with respect to melt temperature. In fact, when one evaluates the composition of Frit 418-7D, it lies within the current Frit 418 vendor specifications and therefore could have been produced by the vendor targeting the nominal composition of Frit 418.« less

Digestion of Crystalline Silicotitanate (CST)

DOE Office of Scientific and Technical Information (OSTI.GOV)

DARREL, WALKER

2004-11-04

Researchers tested methods for chemically dissolving crystalline silicotitanate (CST) as a substitute for mechanical grinding to reduce particle size before vitrification. Testing used the commercially available form of CST, UOP IONSIV(R) IE-911. Reduction of the particle size to a range similar to that of the glass frit used by the Defense Waste Processing Facility (DWPF) could reduce problems with coupling cesium ion exchange to the vitrification process. This study found that IONSIV(R) IE-911 dissolves completely using a combination of acid, hydrogen peroxide, and fluoride ion. Neutralization of the resulting acidic solution precipitates components of the IONSIV(R) IE-911. Digestion requires extremelymore » corrosive conditions. Also, large particles may reform during neutralization, and the initiation and rate of gas generation are unpredictable. Therefore, the method is not recommended as a substitute for mechanical grinding.« less

Nuclear criticality safety evaluation of the passage of decontaminated salt solution from the ITP filters into tank 50H for interim storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hobbs, D.T.; Davis, J.R.

This report assesses the nuclear criticality safety associated with the decontaminated salt solution after passing through the In-Tank Precipitation (ITP) filters, through the stripper columns and into Tank 50H for interim storage until transfer to the Saltstone facility. The criticality safety basis for the ITP process is documented. Criticality safety in the ITP filtrate has been analyzed under normal and process upset conditions. This report evaluates the potential for criticality due to the precipitation or crystallization of fissionable material from solution and an ITP process filter failure in which insoluble material carryover from salt dissolution is present. It is concludedmore » that no single inadvertent error will cause criticality and that the process will remain subcritical under normal and credible abnormal conditions.« less

PROCESSING ALTERNATIVES FOR DESTRUCTION OF TETRAPHENYLBORATE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D; Thomas Peters, T; Samuel Fink, S

Two processes were chosen in the 1980's at the Savannah River Site (SRS) to decontaminate the soluble High Level Waste (HLW). The In Tank Precipitation (ITP) process (1,2) was developed at SRS for the removal of radioactive cesium and actinides from the soluble HLW. Sodium tetraphenylborate was added to the waste to precipitate cesium and monosodium titanate (MST) was added to adsorb actinides, primarily uranium and plutonium. Two products of this process were a low activity waste stream and a concentrated organic stream containing cesium tetraphenylborate and actinides adsorbed on monosodium titanate (MST). A copper catalyzed acid hydrolysis process wasmore » built to process (3, 4) the Tank 48H cesium tetraphenylborate waste in the SRS's Defense Waste Processing Facility (DWPF). Operation of the DWPF would have resulted in the production of benzene for incineration in SRS's Consolidated Incineration Facility. This process was abandoned together with the ITP process in 1998 due to high benzene in ITP caused by decomposition of excess sodium tetraphenylborate. Processing in ITP resulted in the production of approximately 1.0 million liters of HLW. SRS has chosen a solvent extraction process combined with adsorption of the actinides to decontaminate the soluble HLW stream (5). However, the waste in Tank 48H is incompatible with existing waste processing facilities. As a result, a processing facility is needed to disposition the HLW in Tank 48H. This paper will describe the process for searching for processing options by SRS task teams for the disposition of the waste in Tank 48H. In addition, attempts to develop a caustic hydrolysis process for in tank destruction of tetraphenylborate will be presented. Lastly, the development of both a caustic and acidic copper catalyzed peroxide oxidation process will be discussed.« less

Results from tests of TFL Hydragard sampling loop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steimke, J.L.

When the Defense Waste Processing Facility (DWPF) is operational, processed radioactive sludge will be transferred in batches to the Slurry Mix Evaporator (SME), where glass frit will be added and the contents concentrated by boiling. Batches of the slurry mixture are transferred from the SME to the Melter Feed Tank (MFT). Hydragard{reg_sign} sampling systems are used on the SME and the MFT for collecting slurry samples in vials for chemical analysis. An accurate replica of the Hydragard sampling system was built and tested in the thermal Fluids Laboratory (TFL) to determine the hydragard accuracy. It was determined that the originalmore » Hydragard valve frequently drew a non-representative sample stream through the sample vial that ranged from frit enriched to frit depleted. The Hydragard valve was modified by moving the plunger and its seat backwards so that the outer surface of the plunger was flush with the inside diameter of the transfer line when the valve was open. The slurry flowing through the vial accurately represented the composition of the slurry in the reservoir for two types of slurries, different dilution factors, a range of transfer flows and a range of vial flows. It was then found that the 15 ml of slurry left in the vial when the Hydragard valve was closed, which is what will be analyzed at DWPF, had a lower ratio of frit to sludge as characterized by the lithium to iron ratio than the slurry flowing through it. The reason for these differences is not understood at this time but it is recommended that additional experimentation be performed with the TFL Hydragard loop to determine the cause.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, K. M.

The U.S. Department of Energy (DOE), Office of Environmental Management (EM) is sponsoring an international, collaborative project to develop a fundamental model for sulfate solubility in nuclear waste glass. The solubility of sulfate has a significant impact on the achievable waste loading for nuclear waste forms within the DOE complex. These wastes can contain relatively high concentrations of sulfate, which has low solubility in borosilicate glass. This is a significant issue for low-activity waste (LAW) glass and is projected to have a major impact on the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Sulfate solubility has also been amore » limiting factor for recent high level waste (HLW) sludge processed at the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF). The low solubility of sulfate in glass, along with melter and off-gas corrosion constraints, dictate that the waste be blended with lower sulfate concentration waste sources or washed to remove sulfate prior to vitrification. The development of enhanced borosilicate glass compositions with improved sulfate solubility will allow for higher waste loadings and accelerate mission completion.The objective of the current scope being pursued by SHU is to mature the sulfate solubility model to the point where it can be used to guide glass composition development for DWPF and WTP, allowing for enhanced waste loadings and waste throughput at these facilities. A series of targeted glass compositions was selected to resolve data gaps in the model and is identified as Stage III. SHU fabricated these glasses and sent samples to SRNL for chemical composition analysis. SHU will use the resulting data to enhance the sulfate solubility model and resolve any deficiencies. In this report, SRNL provides chemical analyses for the Stage III, simulated HLW glasses fabricated by SHU in support of the sulfate solubility model development.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, D. H.; Reigel, M. M.

A full-scale formed core sampler was designed and functionally tested for use in the Saltstone Disposal Facility (SDF). Savannah River National Laboratory (SRNL) was requested to compare properties of the formed core samples and core drilled samples taken from adjacent areas in the full-scale sampler. While several physical properties were evaluated, the primary property of interest was hydraulic conductivity. Differences in hydraulic conductivity between the samples from the formed core sampler and those representing the bulk material were noted with respect to the initial handling and storage of the samples. Due to testing conditions, the site port samples were exposedmore » to uncontrolled temperature and humidity conditions prior to testing whereas the formed core samples were kept in sealed containers with minimal exposure to an uncontrolled environment prior to testing. Based on the results of the testing, no significant differences in porosity or density were found between the formed core samples and those representing the bulk material in the test stand.« less

OPC Paste Samples Exposed To Aggressive Solutions. Cementitious Barriers Partnership

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langton, C.

2014-11-01

The study presented in this report focused on a low-activity wasteform containing a high-pH pore solution with a significant level of sulfate. The purpose of the study was to improve understanding of the complex concrete/wasteform reactive transport problem, in particular, the role of pH in sulfate attack. Paste samples prepared at three different water-to-cement ratios were tested. The mixtures were prepared with ASTM Type I cement, without additional admixtures. The samples were exposed to two different sodium sulfate contact solutions. The first solution was prepared at 0.15M Na 2SO 4. The second solution also incorporated 0.5M NaOH, to mimic themore » high pH conditions found in Saltstone. The data collected indicated that, in Na 2SO 4 solution, damage occurs to the pastes. In the case of the high-pH sulfate solution (Na 2SO 4 + NaOH), no signs of damage were observed on any of the paste mixtures. These results indicate that the high sulfate content found in the wasteform pore solution will not necessarily lead to severe damage to concrete. Good-quality mixtures could thus prove durable over the long term, and act as an effective barrier to prevent radionuclides from reaching the environment.« less

Impact of scaling on the nitric-glycolic acid flowsheet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D.

Savannah River Remediation (SRR) is considering using glycolic acid as a replacement for formic acid in Sludge Receipt and Adjustment Tank (SRAT) processing in the Defense Waste Processing Facility (DWPF). Catalytic decomposition of formic acid is responsible for the generation of hydrogen, a potentially flammable gas, during processing. To prevent the formation of a flammable mixture in the offgas, an air purge is used to dilute the hydrogen concentration below the 60% of the Composite Lower Flammability Limit (CLFL). The offgas is continuously monitored for hydrogen using Gas Chromatographs (GCs). Since formic acid is much more volatile and toxic thanmore » glycolic acid, a formic acid spill would lead to the release of much larger quantities to the environment. Switching from formic acid to glycolic acid is expected to eliminate the hydrogen flammability hazard leading to lower air purges, thus downgrading of Safety Significant GCs to Process Support GCs, and minimizing the consequence of a glycolic acid tank leak in DWPF. Overall this leads to a reduction in process operation costs and an increase in safety margin. Experiments were completed at three different scales to demonstrate that the nitric-glycolic acid flowsheet scales from the 4-L lab scale to the 22-L bench scale and 220-L engineering scale. Ten process demonstrations of the sludge-only flowsheet for SRAT and Slurry Mix Evaporator (SME) cycles were performed using Sludge Batch 8 (SB8)-Tank 40 simulant. No Actinide Removal Process (ARP) product or strip effluent was added during the runs. Six experiments were completed at the 4-L scale, two experiments were completed at the 22-L scale, and two experiments were completed at the 220-L scale. Experiments completed at the 4-L scale (100 and 110% acid stoichiometry) were repeated at the 22-L and 220-L scale for scale comparisons.« less

Long-term high-level waste technology. Composite report

NASA Astrophysics Data System (ADS)

Cornman, W. R.

1981-12-01

Research and development studies on the immobilization of high-level wastes from the chemical reprocessing of nuclear reactor fuels are summarized. The reports are grouped under the following tasks: (1) program management and support; (2) waste preparation; (3) waste fixation; and (4) final handling. Some of the highlights are: leaching properties were obtained for titanate and tailored ceramic materials being developed at ICPP to immobilize zirconia calcine; comparative leach tests, hot-cell tests, and process evaluations were conducted of waste form alternatives to borosilicate glass for the immobilization of SRP high-level wastes, experiments were run at ANL to qualify neutron activation analysis and radioactive tracers for measuring leach rates from simulated waste glasses; comparative leach test samples of SYNROC D were prepared, characterized, and tested at LLNL; encapsulation of glass marbles with lead or lead alloys was demonstrated on an engineering scale at PNL; a canister for reference Commercial HLW was designed at PNL; a study of the optimization of salt-crete was completed at SRL; a risk assessment showed that an investment for tornado dampers in the interim storage building of the DWPF is unjustified.

IMPACT OF NOBLE METALS AND MERCURY ON HYDROGEN GENERATION DURING HIGH LEVEL WASTE PRETREATMENT AT THE SAVANNAH RIVER SITE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M; Tommy Edwards, T; David Koopman, D

2009-03-03

The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies radioactive High Level Waste (HLW) for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. HLW consists of insoluble metal hydroxides (primarily iron, aluminum, calcium, magnesium, manganese, and uranium) and soluble sodium salts (carbonate, hydroxide, nitrite, nitrate, and sulfate). The pretreatment process in the Chemical Processing Cell (CPC) consists of two process tanks, the Sludge Receipt and Adjustment Tank (SRAT) and the Slurry Mix Evaporator (SME) as well as a melter feed tank. During SRAT processing, nitric and formic acids are addedmore » to the sludge to lower pH, destroy nitrite and carbonate ions, and reduce mercury and manganese. During the SME cycle, glass formers are added, and the batch is concentrated to the final solids target prior to vitrification. During these processes, hydrogen can be produced by catalytic decomposition of excess formic acid. The waste contains silver, palladium, rhodium, ruthenium, and mercury, but silver and palladium have been shown to be insignificant factors in catalytic hydrogen generation during the DWPF process. A full factorial experimental design was developed to ensure that the existence of statistically significant two-way interactions could be determined without confounding of the main effects with the two-way interaction effects. Rh ranged from 0.0026-0.013% and Ru ranged from 0.010-0.050% in the dried sludge solids, while initial Hg ranged from 0.5-2.5 wt%, as shown in Table 1. The nominal matrix design consisted of twelve SRAT cycles. Testing included: a three factor (Rh, Ru, and Hg) study at two levels per factor (eight runs), three duplicate midpoint runs, and one additional replicate run to assess reproducibility away from the midpoint. Midpoint testing was used to identify potential quadratic effects from the three factors. A single sludge simulant was used for all tests and was spiked with the required amount of noble metals immediately prior to performing the test. Acid addition was kept effectively constant except to compensate for variations in the starting mercury concentration. SME cycles were also performed during six of the tests.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boggess, A.

Existing models and simulants of tank disposition media at SRS have presumed the presence of high concentrations of inorganic mercury. However, recent quarterly tank analyses show that mercury is present as organomercurial species at concentrations that may present challenges to remediation and disposition and may exceed the Saltstone Waste Acceptance Criteria (WAC). To-date, methylmercury analysis for Savannah River Remediation (SRR) has been performed off-site by Eurofins Scientific (Lancaster, PA). A series of optimization and validation experiments has been performed at SRNL, which has resulted in the development of on-site organomercury speciation capabilities using purge and trap gas chromatography coupled withmore » thermal desorption cold vapor atomic fluorescence spectroscopy (P&T GC/CVAFS). Speciation has been achieved for methylmercury, with a method reporting limit (MRL) values of 1.42 pg for methylmercury. Results obtained by SRNL from the analysis of past quarterly samples from tanks 21, 40, and 50 have demonstrated statistically indistinguishable concentration values compared with the concentration data obtained from Eurofins, while the data from SRNL has demonstrated significantly improved precision and processing time.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zamecnik, J. R.; Edwards, T. B.

The conversions of nitrite to nitrate, the destruction of glycolate, and the conversion of glycolate to formate and oxalate were modeled for the Nitric-Glycolic flowsheet using data from Chemical Process Cell (CPC) simulant runs conducted by SRNL from 2011 to 2015. The goal of this work was to develop empirical correlations for these variables versus measureable variables from the chemical process so that these quantities could be predicted a-priori from the sludge composition and measurable processing variables. The need for these predictions arises from the need to predict the REDuction/OXidation (REDOX) state of the glass from the Defense Waste Processingmore » Facility (DWPF) melter. This report summarizes the initial work on these correlations based on the aforementioned data. Further refinement of the models as additional data is collected is recommended.« less

CEMENTITIOUS BARRIERS PARTNERSHIP FY13 MID-YEAR REPORT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burns, H.; Flach, G.; Langton, C.

2013-05-01

In FY2013, the Cementitious Barriers Partnership (CBP) is continuing in its effort to develop and enhance software tools demonstrating tangible progress toward fulfilling the objective of developing a set of tools to improve understanding and prediction of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. In FY2012, the CBP released the initial inhouse “Beta-version” of the CBP Software Toolbox, a suite of software for simulating reactive transport in cementitious materials and important degradation phenomena. The current primary software components are LeachXS/ORCHESTRA, STADIUM, and a GoldSim interface for probabilistic analysis of selected degradation scenarios. THAMESmore » is a planned future CBP Toolbox component (FY13/14) focused on simulation of the microstructure of cementitious materials and calculation of resultant hydraulic and constituent mass transfer parameters needed in modeling. This past November, the CBP Software Toolbox Version 1.0 was released that supports analysis of external sulfate attack (including damage mechanics), carbonation, and primary constituent leaching. The LeachXS component embodies an extensive material property measurements database along with chemical speciation and reactive mass transport simulation cases with emphasis on leaching of major, trace and radionuclide constituents from cementitious materials used in DOE facilities, such as Saltstone (Savannah River) and Cast Stone (Hanford), tank closure grouts, and barrier concretes. STADIUM focuses on the physical and structural service life of materials and components based on chemical speciation and reactive mass transport of major cement constituents and aggressive species (e.g., chloride, sulfate, etc.). The CBP issued numerous reports and other documentation that accompanied the “Version 1.0” release including a CBP Software Toolbox User Guide and Installation Guide. These documents, as well as, the presentations from the CBP Software Toolbox Demonstration and User Workshop, which are briefly described below, can be accessed from the CBP webpage at http://cementbarriers.org/. The website was recently modified to describe the CBP Software Toolbox and includes an interest form for application to use the software. The CBP FY13 program is continuing research to improve and enhance the simulation tools as well as develop new tools that model other key degradation phenomena not addressed in Version 1.0. Also efforts to continue to verify the various simulation tools thru laboratory experiments and analysis of field specimens are ongoing to quantify and reduce the uncertainty associated with performance assessments are ongoing. This mid-year report also includes both a summary on the FY13 software accomplishments in addition to the release of Version 1.0 of the CBP Software Toolbox and the various experimental programs that are providing data for calibration and validation of the CBP developed software. The focus this year for experimental studies was to measure transport in cementitious material by utilization of a leaching method and reduction capacity of saltstone field samples. Results are being used to calibrate and validate the updated carbonation model.« less

Overview of Corrosion, Erosion, and Synergistic Effects of Erosion and Corrosion in the WTP Pre-treatment Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Imrich, K. J.

2015-03-27

Corrosion is an extremely complex process that is affected by numerous factors. Addition of a flowing multi-phase solution further complicates the analysis. The synergistic effects of the multiple corrosive species as well as the flow-induced synergistic effects from erosion and corrosion must be thoroughly evaluated in order to predict material degradation responses. Public domain data can help guide the analysis, but cannot reliably provide the design basis especially when the process is one-of-a-kind, designed for 40 plus years of service, and has no viable means for repair or replacement. Testing in representative simulants and environmental conditions with prototypic components willmore » provide a stronger technical basis for design. This philosophy was exemplified by the Defense Waste Processing Facility (DWPF) at the Savannah River Site and only after 15 plus years of successful operation has it been validated. There have been “hiccups”, some identified during the cold commissioning phase and some during radioactive operations, but they were minor and overcome. In addition, the system is robust enough to tolerate most flowsheet changes and the DWPF design allows minor modifications and replacements – approaches not available with the Hanford Waste Treatment Plant (WTP) “Black Cell” design methodology. Based on the available data, the synergistic effect between erosion and corrosion is a credible – virtually certain – degradation mechanism and must be considered for the design of the WTP process systems. Testing is recommended due to the number of variables (e.g., material properties, process parameters, and component design) that can affect synergy between erosion and corrosion and because the available literature is of limited applicability for the complex process chemistries anticipated in the WTP. Applicable testing will provide a reasonable and defensible path forward for design of the WTP Black Cell and Hard-to-Reach process equipment. These conclusions are consistent with findings from the various Bechtel National Inc., Independent Review Teams, and Department of Energy (DOE) reviews. A test methodology is outlined, which should provide a clear, logical road map for the testing that is necessary to provide applicable and defensible data essential to support design calculations.« less

Description of Defense Waste Processing Facility reference waste form and canister. Revision 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baxter, R.G.

1983-08-01

The Defense Waste Processing Facility (DWPF) will be located at the Savannah River Plant in Aiken, SC, and is scheduled for construction authorization during FY-1984. The reference waste form is borosilicate glass containing approx. 28 wt % sludge oxides, with the balance glass frit. Borosilicate glass was chosen because of its high resistance to leaching by water, its relatively high solubility for nuclides found in the sludge, and its reasonably low melting temperature. The glass frit contains about 58% SiO/sub 2/ and 15% B/sub 2/O/sub 3/. Leachabilities of SRP waste glasses are expected to approach 10/sup -8/ g/m/sup 2/-day basedmore » upon 1000-day tests using glasses containing SRP radioactive waste. Tests were performed under a wide variety of conditions simulating repository environments. The canister is filled with 3260 lb of glass which occupies about 85% of the free canister volume. The filled canister will generate approx. 470 watts when filled with oxides from 5-year-old sludge and 15-year-old supernate from the sludge and supernate processes. The radionuclide content of the canister is about 177,000 ci, with a radiation level of 5500 rem/h at canister surface contact. The reference canister is fabricated of standard 24-in.-OD, Schedule 20, 304L stainless steel pipe with a dished bottom, domed head, and a combined lifting and welding flange on the head neck. The overall canister length is 9 ft 10 in. with a 3/8-in. wall thickness. The 3-m canister length was selected to reduce equipment cell height in the DWPF to a practical size. The canister diameter was selected as an optimum size from glass quality considerations, a logical size for repository handling and to ensure that a filled canister with its double containment shipping cask could be accommodated on a legal-weight truck. The overall dimensions and weight appear to be compatible with preliminary assessments of repository requirements. 10 references.« less

Impact of Salt Waste Processing Facility Streams on the Nitric-Glycolic Flowsheet in the Chemical Processing Cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martino, C.

An evaluation of the previous Chemical Processing Cell (CPC) testing was performed to determine whether the planned concurrent operation, or “coupled” operations, of the Defense Waste Processing Facility (DWPF) with the Salt Waste Processing Facility (SWPF) has been adequately covered. Tests with the nitricglycolic acid flowsheet, which were both coupled and uncoupled with salt waste streams, included several tests that required extended boiling times. This report provides the evaluation of previous testing and the testing recommendation requested by Savannah River Remediation. The focus of the evaluation was impact on flammability in CPC vessels (i.e., hydrogen generation rate, SWPF solvent components,more » antifoam degradation products) and processing impacts (i.e., acid window, melter feed target, rheological properties, antifoam requirements, and chemical composition).« less

Definition of an Acceptable Glass composition Region (AGCR) via an Index System and a Partitioning Function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D. K.; Taylor, A. S.; Edwards, T.B.

2005-06-26

The objective of this investigation was to appeal to the available ComPro{trademark} database of glass compositions and measured PCTs that have been generated in the study of High Level Waste (HLW)/Low Activity Waste (LAW) glasses to define an Acceptable Glass Composition Region (AGCR). The term AGCR refers to a glass composition region in which the durability response (as defined by the Product Consistency Test (PCT)) is less than some pre-defined, acceptable value that satisfies the Waste Acceptance Product Specifications (WAPS)--a value of 10 g/L was selected for this study. To assess the effectiveness of a specific classification or index systemmore » to differentiate between acceptable and unacceptable glasses, two types of errors (Type I and Type II errors) were monitored. A Type I error reflects that a glass with an acceptable durability response (i.e., a measured NL [B] < 10 g/L) is classified as unacceptable by the system of composition-based constraints. A Type II error occurs when a glass with an unacceptable durability response is classified as acceptable by the system of constraints. Over the course of the efforts to meet this objective, two approaches were assessed. The first (referred to as the ''Index System'') was based on the use of an evolving system of compositional constraints which were used to explore the possibility of defining an AGCR. This approach was primarily based on ''glass science'' insight to establish the compositional constraints. Assessments of the Brewer and Taylor Index Systems did not result in the definition of an AGCR. Although the Taylor Index System minimized Type I errors which allowed access to composition regions of interest to improve melt rate or increase waste loadings for DWPF as compared to the current durability model, Type II errors were also committed. In the context of the application of a particular classification system in the process control system, Type II errors are much more serious than Type I errors. A Type I error only reflects that the particular constraint system being used is overly conservative (i.e., its application restricts access to glasses that have an acceptable measured durability response). A Type II error results in a more serious misclassification that could result in allowing the transfer of a Slurry Mix Evaporator (SME) batch to the melter, which is predicted to produce a durable product based on the specific system applied but in reality does not meet the defined ''acceptability'' criteria. More specifically, a nondurable product could be produced in DWPF. Given the presence of Type II errors, the Index System approach was deemed inadequate for further implementation consideration at the DWPF. The second approach (the JMP partitioning process) was purely data driven and empirically derived--glass science was not a factor. In this approach, the collection of composition--durability data in ComPro was sequentially partitioned or split based on the best available specific criteria and variables. More specifically, the JMP software chose the oxide (Al{sub 2}O{sub 3} for this dataset) that most effectively partitions the PCT responses (NL [B]'s)--perhaps not 100% effective based on a single oxide. Based on this initial split, a second request was made to split a particular set of the ''Y'' values (good or bad PCTs based on the 10 g/L limit) based on the next most critical ''X'' variable. This ''splitting'' or ''partitioning'' process was repeated until an AGCR was defined based on the use of only 3 oxides (Al{sub 2}O{sub 3}, CaO, and MgO) and critical values of > 3.75 wt% Al{sub 2}O{sub 3}, {ge} 0.616 wt% CaO, and < 3.521 wt% MgO. Using this set of criteria, the ComPro database was partitioned in which no Type II errors were committed. The automated partitioning function screened or removed 978 of the 2406 ComPro glasses which did cause some initial concerns regarding excessive conservatism regardless of its ability to identify an AGCR. However, a preliminary review of glasses within the 1428 ''acceptable'' glasses defining the ACGR includes glass systems of interest to support the accelerated mission.« less

Final Report - "Foaming and Antifoaming and Gas Entrainment in Radioactive Waste Pretreatment and Immobilization Processes"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wasan, Darsh T.

2007-10-09

The Savannah River Site (SRS) and Hanford site are in the process of stabilizing millions of gallons of radioactive waste slurries remaining from production of nuclear materials for the Department of Energy (DOE). The Defense Waste Processing Facility (DWPF) at SRS is currently vitrifying the waste in borosilicate glass, while the facilities at the Hanford site are in the construction phase. Both processes utilize slurry-fed joule-heated melters to vitrify the waste slurries. The DWPF has experienced difficulty during operations. The cause of the operational problems has been attributed to foaming, gas entrainment and the rheological properties of the process slurries.more » The rheological properties of the waste slurries limit the total solids content that can be processed by the remote equipment during the pretreatment and meter feed processes. Highly viscous material can lead to air entrainment during agitation and difficulties with pump operations. Excessive foaming in waste evaporators can cause carryover of radionuclides and non-radioactive waste to the condensate system. Experimental and theoretical investigations of the surface phenomena, suspension rheology and bubble generation of interactions that lead to foaming and air entrainment problems in the DOE High Level and Low Activity Radioactive Waste separation and immobilization processes were pursued under this project. The first major task accomplished in the grant proposal involved development of a theoretical model of the phenomenon of foaming in a three-phase gas-liquid-solid slurry system. This work was presented in a recently completed Ph.D. thesis (9). The second major task involved the investigation of the inter-particle interaction and microstructure formation in a model slurry by the batch sedimentation method. Both experiments and modeling studies were carried out. The results were presented in a recently completed Ph.D. thesis. The third task involved the use of laser confocal microscopy to study the effectiveness of three slurry rheology modifiers. An effective modifier was identified which resulted in lowering the yield stress of the waste simulant. Therefore, the results of this research have led to the basic understanding of the foaming/antifoaming mechanism in waste slurries as well as identification of a rheology modifier, which enhances the processing throughput, and accelerates the DOE mission. The objectives of this research effort were to develop a fundamental understanding of the physico-chemical mechanisms that produced foaming and air entrainment in the DOE High Level (HLW) and Low Activity (LAW) radioactive waste separation and immobilization processes, and to develop and test advanced antifoam/defoaming/rheology modifier agents. Antifoams/rheology modifiers developed from this research ere tested using non-radioactive simulants of the radioactive wastes obtained from Hanford and the Savannah River Site (SRS).« less

ANALYTICAL PLANS SUPPORTING THE SWPF GAP ANALYSIS BEING CONDUCTED WITH ENERGYSOLUTIONS AND THE VITREOUS STATE LABORATORY AT THE CUA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.; Peeler, D.

2014-10-28

EnergySolutions (ES) and its partner, the Vitreous State Laboratory (VSL) of The Catholic University of America (CUA), are to provide engineering and technical services support to Savannah River Remediation, LLC (SRR) for ongoing operation of the Defense Waste Processing Facility (DWPF) flowsheet as well as for modifications to improve overall plant performance. SRR has requested that the glass formulation team of Savannah River National Laboratory (SRNL) and ES-VSL develop a technical basis that validates the current Product Composition Control System models for use during the processing of the coupled flowsheet or that leads to the refinements of or modifications tomore » the models that are needed so that they may be used during the processing of the coupled flowsheet. SRNL has developed a matrix of test glasses that are to be batched and fabricated by ES-VSL as part of this effort. This document provides two analytical plans for use by ES-VSL: one plan is to guide the measurement of the chemical composition of the study glasses while the second is to guide the measurement of the durability of the study glasses based upon the results of testing by ASTM’s Product Consistency Test (PCT) Method A.« less

ROAD MAP FOR DEVELOPMENT OF CRYSTAL-TOLERANT HIGH LEVEL WASTE GLASSES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, K.; Peeler, D.; Herman, C.

The U.S. Department of Energy (DOE) is building a Tank Waste Treatment and Immobilization Plant (WTP) at the Hanford Site in Washington to remediate 55 million gallons of radioactive waste that is being temporarily stored in 177 underground tanks. Efforts are being made to increase the loading of Hanford tank wastes in glass while meeting melter lifetime expectancies and process, regulatory, and product quality requirements. This road map guides the research and development for formulation and processing of crystaltolerant glasses, identifying near- and long-term activities that need to be completed over the period from 2014 to 2019. The primary objectivemore » is to maximize waste loading for Hanford waste glasses without jeopardizing melter operation by crystal accumulation in the melter or melter discharge riser. The potential applicability to the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF) will also be addressed in this road map. The planned research described in this road map is motivated by the potential for substantial economic benefits (significant reductions in glass volumes) that will be realized if the current constraints (T1% for WTP and TL for DWPF) are approached in an appropriate and technically defensible manner for defense waste and current melter designs. The basis of this alternative approach is an empirical model predicting the crystal accumulation in the WTP glass discharge riser and melter bottom as a function of glass composition, time, and temperature. When coupled with an associated operating limit (e.g., the maximum tolerable thickness of an accumulated layer of crystals), this model could then be integrated into the process control algorithms to formulate crystal-tolerant high-level waste (HLW) glasses targeting high waste loadings while still meeting process related limits and melter lifetime expectancies. The modeling effort will be an iterative process, where model form and a broader range of conditions, e.g., glass composition and temperature, will evolve as additional data on crystal accumulation are gathered. Model validation steps will be included to guide the development process and ensure the value of the effort (i.e., increased waste loading and waste throughput). A summary of the stages of the road map for developing the crystal-tolerant glass approach, their estimated durations, and deliverables is provided.« less

SIMPLE TRANSIENT CALCULATIONS OF CELL FLAMMABLE GAS CONCENTRATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

NOEMAIL), J; David Allison; John Mccord, J

2009-05-06

The Saltstone Facility at Savannah River Site (SRS) mixes low-level radiological liquid waste with grout for permanent disposal as cement in vault cells. The grout mixture is poured into each cell in approximately 17 batches (8 to 10 hours duration). The grout mixture contains ten flammable gases of concern that are released from the mixture into the cell. Prior to operations, simple parametric transient calculations were performed to develop batch parameters (including schedule of batch pours) to support operational efficiency while ensuring that a flammable gas mixture does not develop in the cell vapor space. The analysis demonstrated that amore » nonflammable vapor space environment can be achieved, with workable operational constraints, without crediting the ventilation flow as a safety system control. Isopar L was identified as the primary flammable gas of concern. The transient calculations balanced inflows of the flammable gases into the vapor space with credited outflows of diurnal breathing through vent holes and displacement from new grout pours and gases generated. Other important features of the analyses included identifying conditions that inhibited a well-mixed vapor space, the expected frequency and duration of such conditions, and the estimated level of stratification that could develop.« less

Glycolic acid physical properties and impurities assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D. P.; Pickenheim, B. R.; Hay, M. S.

This document has been revised to add analytical data for fresh, 1 year old, and 4 year old glycolic acid as recommended in Revision 2 of this document. This was needed to understand the concentration of formaldehyde and methoxyacetic acid, impurities present in the glycolic acid used in Savannah River National Laboratory (SRNL) experiments. Based on this information, the concentration of these impurities did not change during storage. These impurities were in the glycolic acid used in the testing included in this report and in subsequent testing using DuPont (now called Chemours) supplied Technical Grade 70 wt% glycolic acid. However,more » these impurities were not reported in the first two versions of this report. The Defense Waste Processing Facility (DWPF) is planning to implement a nitric-glycolic acid flowsheets to increase attainment to meet closure commitment dates during Sludge Batch 9. In fiscal year 2009, SRNL was requested to determine the physical properties of formic and glycolic acid blends.« less

Defense Waste Processing Facility Nitric- Glycolic Flowsheet Chemical Process Cell Chemistry: Part 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zamecnik, J.; Edwards, T.

The conversions of nitrite to nitrate, the destruction of glycolate, and the conversion of glycolate to formate and oxalate were modeled for the Nitric-Glycolic flowsheet using data from Chemical Process Cell (CPC) simulant runs conducted by Savannah River National Laboratory (SRNL) from 2011 to 2016. The goal of this work was to develop empirical correlation models to predict these values from measureable variables from the chemical process so that these quantities could be predicted a-priori from the sludge or simulant composition and measurable processing variables. The need for these predictions arises from the need to predict the REDuction/OXidation (REDOX) statemore » of the glass from the Defense Waste Processing Facility (DWPF) melter. This report summarizes the work on these correlations based on the aforementioned data. Previous work on these correlations was documented in a technical report covering data from 2011-2015. This current report supersedes this previous report. Further refinement of the models as additional data are collected is recommended.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jain, V.; Shah, H.; Bannochie, C. J.

Mercury (Hg) in the Savannah River Site Liquid Waste System (LWS) originated from decades of canyon processing where it was used as a catalyst for dissolving the aluminum cladding of reactor fuel. Approximately 60 metric tons of mercury is currently present throughout the LWS. Mercury has long been a consideration in the LWS, from both hazard and processing perspectives. In February 2015, a Mercury Program Team was established at the request of the Department of Energy to develop a comprehensive action plan for long-term management and removal of mercury. Evaluation was focused in two Phases. Phase I activities assessed themore » Liquid Waste inventory and chemical processing behavior using a system-by-system review methodology, and determined the speciation of the different mercury forms (Hg+, Hg++, elemental Hg, organomercury, and soluble versus insoluble mercury) within the LWS. Phase II activities are building on the Phase I activities, and results of the LWS flowsheet evaluations will be summarized in three reports: Mercury Behavior in the Salt Processing Flowsheet (i.e. this report); Mercury Behavior in the Defense Waste Processing Facility (DWPF) Flowsheet; and Mercury behavior in the Tank Farm Flowsheet (Evaporator Operations). The evaluation of the mercury behavior in the salt processing flowsheet indicates, inter alia, the following: (1) In the assembled Salt Batches 7, 8 and 9 in Tank 21, the total mercury is mostly soluble with methylmercury (MHg) contributing over 50% of the total mercury. Based on the analyses of samples from 2H Evaporator feed and drop tanks (Tanks 38/43), the source of MHg in Salt Batches 7, 8 and 9 can be attributed to the 2H evaporator concentrate used in assembling the salt batches. The 2H Evaporator is used to evaporate DWPF recycle water. (2) Comparison of data between Tank 21/49, Salt Solution Feed Tank (SSFT), Decontaminated Salt Solution Hold Tank (DSSHT), and Tank 50 samples suggests that the total mercury as well as speciated forms in the assembled salt batches in Tanks 21/49 pass through the Actinide Removal Process (ARP) / Modular Caustic Side Solvent Extraction Unit (MCU) process to Tank 50 with no significant change in the mercury chemistry. (3) In Tank 50, Decontaminated Salt Solution (DSS) from ARP/MCU is the major contributor to the total mercury including MHg. (4) Speciation analyses of TCLP leached solutions of the grout samples prepared from Tank 21, as well as Tank 50 samples, show the majority of the mercury released in the solution is MHg.« less

Groundwater flow simulation of the Savannah River Site general separations area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flach, G.; Bagwell, L.; Bennett, P.

The most recent groundwater flow model of the General Separations Area, Savannah River Site, is referred to as the “GSA/PORFLOW” model. GSA/PORFLOW was developed in 2004 by porting an existing General Separations Area groundwater flow model from the FACT code to the PORFLOW code. The preceding “GSA/FACT” model was developed in 1997 using characterization and monitoring data through the mid-1990’s. Both models were manually calibrated to field data. Significantly more field data have been acquired since the 1990’s and model calibration using mathematical optimization software has become routine and recommended practice. The current task involved updating the GSA/PORFLOW model usingmore » selected field data current through at least 2015, and use of the PEST code to calibrate the model and quantify parameter uncertainty. This new GSA groundwater flow model is named “GSA2016” in reference to the year in which most development occurred. The GSA2016 model update is intended to address issues raised by the DOE Low-Level Waste (LLW) Disposal Facility Federal Review Group (LFRG) in a 2008 review of the E-Area Performance Assessment, and by the Nuclear Regulatory Commission in reviews of tank closure and Saltstone Disposal Facility Performance Assessments.« less

Estimating Residual Solids Volume In Underground Storage Tanks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, Jason L.; Worthy, S. Jason; Martin, Bruce A.

2014-01-08

The Savannah River Site liquid waste system consists of multiple facilities to safely receive and store legacy radioactive waste, treat, and permanently dispose waste. The large underground storage tanks and associated equipment, known as the 'tank farms', include a complex interconnected transfer system which includes underground transfer pipelines and ancillary equipment to direct the flow of waste. The waste in the tanks is present in three forms: supernatant, sludge, and salt. The supernatant is a multi-component aqueous mixture, while sludge is a gel-like substance which consists of insoluble solids and entrapped supernatant. The waste from these tanks is retrieved andmore » treated as sludge or salt. The high level (radioactive) fraction of the waste is vitrified into a glass waste form, while the low-level waste is immobilized in a cementitious grout waste form called saltstone. Once the waste is retrieved and processed, the tanks are closed via removing the bulk of the waste, chemical cleaning, heel removal, stabilizing remaining residuals with tailored grout formulations and severing/sealing external penetrations. The comprehensive liquid waste disposition system, currently managed by Savannah River Remediation, consists of 1) safe storage and retrieval of the waste as it is prepared for permanent disposition; (2) definition of the waste processing techniques utilized to separate the high-level waste fraction/low-level waste fraction; (3) disposition of LLW in saltstone; (4) disposition of the HLW in glass; and (5) closure state of the facilities, including tanks. This paper focuses on determining the effectiveness of waste removal campaigns through monitoring the volume of residual solids in the waste tanks. Volume estimates of the residual solids are performed by creating a map of the residual solids on the waste tank bottom using video and still digital images. The map is then used to calculate the volume of solids remaining in the waste tank. The ability to accurately determine a volume is a function of the quantity and quality of the waste tank images. Currently, mapping is performed remotely with closed circuit video cameras and still photograph cameras due to the hazardous environment. There are two methods that can be used to create a solids volume map. These methods are: liquid transfer mapping / post transfer mapping and final residual solids mapping. The task is performed during a transfer because the liquid level (which is a known value determined by a level measurement device) is used as a landmark to indicate solids accumulation heights. The post transfer method is primarily utilized after the majority of waste has been removed. This method relies on video and still digital images of the waste tank after the liquid transfer is complete to obtain the relative height of solids across a waste tank in relation to known and usable landmarks within the waste tank (cooling coils, column base plates, etc.). In order to accurately monitor solids over time across various cleaning campaigns, and provide a technical basis to support final waste tank closure, a consistent methodology for volume determination has been developed and implemented at SRS.« less

Mercury Reduction and Removal from High Level Waste at the Defense Waste Processing Facility - 12511

DOE Office of Scientific and Technical Information (OSTI.GOV)

Behrouzi, Aria; Zamecnik, Jack

2012-07-01

The Defense Waste Processing Facility processes legacy nuclear waste generated at the Savannah River Site during production of enriched uranium and plutonium required by the Cold War. The nuclear waste is first treated via a complex sequence of controlled chemical reactions and then vitrified into a borosilicate glass form and poured into stainless steel canisters. Converting the nuclear waste into borosilicate glass is a safe, effective way to reduce the volume of the waste and stabilize the radionuclides. One of the constituents in the nuclear waste is mercury, which is present because it served as a catalyst in the dissolutionmore » of uranium-aluminum alloy fuel rods. At high temperatures mercury is corrosive to off-gas equipment, this poses a major challenge to the overall vitrification process in separating mercury from the waste stream prior to feeding the high temperature melter. Mercury is currently removed during the chemical process via formic acid reduction followed by steam stripping, which allows elemental mercury to be evaporated with the water vapor generated during boiling. The vapors are then condensed and sent to a hold tank where mercury coalesces and is recovered in the tank's sump via gravity settling. Next, mercury is transferred from the tank sump to a purification cell where it is washed with water and nitric acid and removed from the facility. Throughout the chemical processing cell, compounds of mercury exist in the sludge, condensate, and off-gas; all of which present unique challenges. Mercury removal from sludge waste being fed to the DWPF melter is required to avoid exhausting it to the environment or any negative impacts to the Melter Off-Gas system. The mercury concentration must be reduced to a level of 0.8 wt% or less before being introduced to the melter. Even though this is being successfully accomplished, the material balances accounting for incoming and collected mercury are not equal. In addition, mercury has not been effectively purified and collected in the Mercury Purification Cell (MPC) since 2008. A significant cleaning campaign aims to bring the MPC back up to facility housekeeping standards. Two significant investigations are being undertaken to restore mercury collection. The SMECT mercury pump has been removed from the tank and will be functionally tested. Also, research is being conducted by the Savannah River National Laboratory to determine the effects of antifoam addition on the behavior of mercury. These path forward items will help us better understand what is occurring in the mercury collection system and ultimately lead to an improved DWPF production rate and mercury recovery rate. (authors)« less

ANALYSIS OF 2H-EVAPORATOR SCALE WALL [HTF-13-82] AND POT BOTTOM [HTF-13-77] SAMPLES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oji, L.

2013-06-21

Savannah River Remediation (SRR) is planning to remove a buildup of sodium aluminosilicate scale from the 2H-evaporator pot by loading and soaking the pot with heated 1.5 M nitric acid solution. Sampling and analysis of the scale material has been performed so that uranium and plutonium isotopic analysis can be input into a Nuclear Criticality Safety Assessment (NCSA) for scale removal by chemical cleaning. Historically, since the operation of the Defense Waste Processing Facility (DWPF), silicon in the DWPF recycle stream combines with aluminum in the typical tank farm supernate to form sodium aluminosilicate scale mineral deposits in the 2Hevaporatormore » pot and gravity drain line. The 2H-evaporator scale samples analyzed by Savannah River National Laboratory (SRNL) came from the bottom cone sections of the 2H-evaporator pot [Sample HTF-13-77] and the wall 2H-evaporator [sample HTF-13-82]. X-ray diffraction analysis (XRD) confirmed that both the 2H-evaporator pot scale and the wall samples consist of nitrated cancrinite (a crystalline sodium aluminosilicate solid) and clarkeite (a uranium oxy-hydroxide mineral). On “as received” basis, the bottom pot section scale sample contained an average of 2.59E+00 ± 1.40E-01 wt % total uranium with a U-235 enrichment of 6.12E-01 ± 1.48E-02 %, while the wall sample contained an average of 4.03E+00 ± 9.79E-01 wt % total uranium with a U-235 enrichment of 6.03E-01% ± 1.66E-02 wt %. The bottom pot section scale sample analyses results for Pu-238, Pu-239, and Pu-241 are 3.16E- 05 ± 5.40E-06 wt %, 3.28E-04 ± 1.45E-05 wt %, and <8.80E-07 wt %, respectively. The evaporator wall scale samples analysis values for Pu-238, Pu-239, and Pu-241 averages 3.74E-05 ± 6.01E-06 wt %, 4.38E-04 ± 5.08E-05 wt %, and <1.38E-06 wt %, respectively. The Pu-241 analyses results, as presented, are upper limit values. These results are provided so that SRR can calculate the equivalent uranium-235 concentrations for the NCSA. Results confirm that the uranium contained in the scale remains depleted with respect to natural uranium. SRNL did not calculate an equivalent U-235 enrichment, which takes into account other fissionable isotopes U-233, Pu-239 and Pu-241. The applicable method for calculation of equivalent U-235 will be determined in the NCSA.« less

Cementitious Barriers Partnership FY2013 End-Year Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flach, G. P.; Langton, C. A.; Burns, H. H.

2013-11-01

In FY2013, the Cementitious Barriers Partnership (CBP) demonstrated continued tangible progress toward fulfilling the objective of developing a set of software tools to improve understanding and prediction of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. In November 2012, the CBP released “Version 1.0” of the CBP Software Toolbox, a suite of software for simulating reactive transport in cementitious materials and important degradation phenomena. In addition, the CBP completed development of new software for the “Version 2.0” Toolbox to be released in early FY2014 and demonstrated use of the Version 1.0 Toolbox on DOEmore » applications. The current primary software components in both Versions 1.0 and 2.0 are LeachXS/ORCHESTRA, STADIUM, and a GoldSim interface for probabilistic analysis of selected degradation scenarios. The CBP Software Toolbox Version 1.0 supports analysis of external sulfate attack (including damage mechanics), carbonation, and primary constituent leaching. Version 2.0 includes the additional analysis of chloride attack and dual regime flow and contaminant migration in fractured and non-fractured cementitious material. The LeachXS component embodies an extensive material property measurements database along with chemical speciation and reactive mass transport simulation cases with emphasis on leaching of major, trace and radionuclide constituents from cementitious materials used in DOE facilities, such as Saltstone (Savannah River) and Cast Stone (Hanford), tank closure grouts, and barrier concretes. STADIUM focuses on the physical and structural service life of materials and components based on chemical speciation and reactive mass transport of major cement constituents and aggressive species (e.g., chloride, sulfate, etc.). THAMES is a planned future CBP Toolbox component focused on simulation of the microstructure of cementitious materials and calculation of resultant hydraulic and constituent mass transfer parameters needed in modeling. Two CBP software demonstrations were conducted in FY2013, one to support the Saltstone Disposal Facility (SDF) at SRS and the other on a representative Hanford high-level waste tank. The CBP Toolbox demonstration on the SDF provided analysis on the most probable degradation mechanisms to the cementitious vault enclosure caused by sulfate and carbonation ingress. This analysis was documented and resulted in the issuance of a SDF Performance Assessment Special Analysis by Liquid Waste Operations this fiscal year. The two new software tools supporting chloride attack and dual-regime flow will provide additional degradation tools to better evaluate performance of DOE and commercial cementitious barriers. The CBP SRNL experimental program produced two patent applications and field data that will be used in the development and calibration of CBP software tools being developed in FY2014. The CBP software and simulation tools varies from other efforts in that all the tools are based upon specific and relevant experimental research of cementitious materials utilized in DOE applications. The CBP FY2013 program involved continuing research to improve and enhance the simulation tools as well as developing new tools that model other key degradation phenomena not addressed in Version 1.0. Also efforts to continue to verify the various simulation tools through laboratory experiments and analysis of field specimens are ongoing and will continue into FY2014 to quantify and reduce the uncertainty associated with performance assessments. This end-year report summarizes FY2013 software development efforts and the various experimental programs that are providing data for calibration and validation of the CBP developed software.« less

EVALUATION OF FABRIC MEMBRANES FOR USE IN SALTSTONE DRAIN WATER SYSTEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pickenheim, B.; Miller, D.; Burket, P.

2012-03-08

Saltstone Disposal Unit 2 contains a sheet drain fabric intended to separate solids from drain water to be returned to the Salt Feed Tank. A similar system installed in Vault 4 appears to be ineffective in keeping solids out of the drain water return lines. Waste Solidification Engineering is considering installation of an additional fabric membrane to supplement the existing sheet drain in SDU 2. Amerdrain 200 is the product currently installed in SDU 2. This product is no longer available, so Sitedrain 94 was used as the replacement product in this testing. Fabrics with apparent opening sizes of 10,more » 25, 50 and 100 microns were evaluated. These fabrics were evaluated under three separate test conditions, a water flow test, a solids retention test and a grout pour test. A flow test with water showed that installation of an additional filter layer will predictably reduce the theoretical flux through the sheet drain. The manufacturer reports the flux for Sitedrain 94 as 150 gpm/ft{sup 2} by ASTM D-4491. This compares reasonably well with the 117 gpm/ft{sup 2} obtained in this testing. A combination of the 10 micron fabric with Sitedrain 94 could be expected to decrease flux by about 10 times as compared to Sitedrain 94 alone. The different media were used to filter a slag and fly ash mixture from water. Slag historically has the smallest nominal particle size of the premix components. Cement was omitted from the test because of its reactivity with water would prohibit accurately particle size measurements of the filtered samples. All four media sizes were able to remove greater than 95% of particles larger than 100 microns from the slurry. The smaller opening sizes were increasingly effective in removing more particles. The 10 micron filter captured 15% of the total amount of solids used in the test. This result implies that some insoluble particles may still be able to enter the drain water collection system, although the overall solids rejection is significantly improved over the current design. Test boxes were filled with grout to evaluate the performance of the sheet drain and fabrics in a simulated vault environment. All of the tests produced a similar amount of drain water, between 8-11% of the amount of water in the mix, which is expected with the targeted formulation. All of the collected drain waters contained some amount of solids, although the 10 micron filter did not appear to allow any premix materials to pass through. The solids collected from this box are believed to consist of calcium carbonate based on one ICP-AES measurement. Any of the four candidate fabrics would be an improvement over the sheet drain alone relative to solids removal. The 10 micron fabric is the only candidate that stopped all premix material from passing. The 10 micron fabric will also cause the largest decrease in flux. This decrease in flux was not enough to inhibit the total amount of drain water removed, but may lead to increased time to remove standing water prior to subsequent pours in the facility. The acceptability of reduced liquid flux through the 10 micron fabric will depend on the amount of excess water to be removed, the time available for water removal and the total area of fabric installed at the disposal cell.« less

The U.S. Department of Energy - Office of Environmental Management Cooperation Program with the Russian Federal Atomic Energy Agency (ROSATOM)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerdes, K.D.; Holtzscheiter, E.W.

2006-07-01

The U.S. Department of Energy's (DOE) Office of Environmental Management (EM) has collaborated with the Russian Federal Atomic Energy Agency - Rosatom (formerly Minatom) for 14 years on waste management challenges of mutual concern. Currently, EM is cooperating with Rosatom to explore issues related to high-level waste and investigate Russian experience and technologies that could support EM site cleanup needs. EM and Rosatom are currently implementing six collaborative projects on high-level waste issues: 1) Advanced Melter Technology Application to the U.S. DOE Defense Waste Processing Facility (DWPF) - Cold Crucible Induction Heated Melter (CCIM); 2) - Design Improvements to themore » Cold Crucible Induction Heated Melter; 3) Long-term Performance of Hanford Low-Activity Glasses in Burial Environments; 4) Low-Activity-Waste (LAW) Glass Sulfur Tolerance; 5) Improved Retention of Key Contaminants of Concern in Low Temperature Immobilized Waste Forms; and, 6) Documentation of Mixing and Retrieval Experience at Zheleznogorsk. Preliminary results and the path forward for these projects will be discussed. An overview of two new projects 7) Entombment technology performance and methodology for the Future 8) Radiation Migration Studies at Key Russian Nuclear Disposal Sites is also provided. The purpose of this paper is to provide an overview of EM's objectives for participating in cooperative activities with the Russian Federal Atomic Energy Agency, present programmatic and technical information on these activities, and outline specific technical collaborations currently underway and planned to support DOE's cleanup and closure mission. (authors)« less

Nitric-glycolic flowsheet reduction/oxidation (redox) model for the defense waste processing facility (DWPF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C. M.; Williams, M. S.; Edwards, T. B.

Control of the REDuction/OXidation (REDOX) state of glasses containing high concentrations of transition metals, such as High Level Waste (HLW) glasses, is critical in order to eliminate processing difficulties caused by overly reduced or overly oxidized melts. Operation of a HLW melter at Fe +2/ΣFe ratios of between 0.09 and 0.33, retains radionuclides in the melt and thus the final glass. Specifically, long-lived radioactive 99Tc species are less volatile in the reduced Tc 4+ state as TcO 2 than as NaTcO 4 or Tc 2O 7, and ruthenium radionuclides in the reduced Ru 4+ state are insoluble RuO 2 inmore » the melt which are not as volatile as NaRuO 4 where the Ru is in the +7 oxidation state. Similarly, hazardous volatile Cr 6+ occurs in oxidized melt pools as Na 2CrO 4 or Na 2Cr 2O 7, while the Cr +3 state is less volatile and remains in the melt as NaCrO 2 or precipitates as chrome rich spinels. The melter REDOX control balances the oxidants and reductants from the feed and from processing additives such as antifoam.« less

Batch Tests with IONSIV IE-911 and a Simulant of the Savannah River Site ''Average'' Supernatant: Distribution Ratios vs Time

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, K.K.; Collins, J.L.; Hunt, R.D.

1999-02-01

The Department of Energy (DOE) is required by law to treat and safely dispose of the radioactive wastes from its nuclear weapon production activities. The primary radionuclide in the DOE liquid wastes or supernatants is {sup 137}Cs. At the Savannah River Site (SRS), the In-Tank Precipitation (ITP) process was selected as the baseline technology to remove {sup 137}Cs from the supernatants, which are stored in underground storage tanks. In the ITP process, tetraphenylborate reacts with the water-soluble cesium to form a precipitant. The treated supernatant can then be immobilized in grout or saltstone and stored in vaults at the SRS.more » However, problems were encountered during the full-scale ITP processing. These difficulties have led to the evaluation of alternative technologies and/or concepts to the currently configured ITP process. The High-Level Waste Salt Disposition Team at the SRS is currently performing this assessment. After an initial screening of all potential alternatives, the Salt Disposition Team selected four primary options to evaluate further before the final down-selection. Crystalline silicotitanate (CST), an inorganic ion exchanger, was chosen as one of the leading alternatives. Since nearly all of the CST tests have been performed on supernatants from Hanford and Oak Ridge, the Salt Disposition Team has requested that personnel at the SRS and Oak Ridge National Laboratory (ORNL) determine the performance of the engineered form of CST, IONSIV{reg_sign} IE-911, with actual and simulated SRS supernatants.« less

Development and Demonstration of Material Properties Database and Software for the Simulation of Flow Properties in Cementitious Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, F.; Flach, G.

This report describes work performed by the Savannah River National Laboratory (SRNL) in fiscal year 2014 to develop a new Cementitious Barriers Project (CBP) software module designated as FLOExcel. FLOExcel incorporates a uniform database to capture material characterization data and a GoldSim model to define flow properties for both intact and fractured cementitious materials and estimate Darcy velocity based on specified hydraulic head gradient and matric tension. The software module includes hydraulic parameters for intact cementitious and granular materials in the database and a standalone GoldSim framework to manipulate the data. The database will be updated with new data asmore » it comes available. The software module will later be integrated into the next release of the CBP Toolbox, Version 3.0. This report documents the development efforts for this software module. The FY14 activities described in this report focused on the following two items that form the FLOExcel package; 1) Development of a uniform database to capture CBP data for cementitious materials. In particular, the inclusion and use of hydraulic properties of the materials are emphasized; and 2) Development of algorithms and a GoldSim User Interface to calculate hydraulic flow properties of degraded and fractured cementitious materials. Hydraulic properties are required in a simulation of flow through cementitious materials such as Saltstone, waste tank fill grout, and concrete barriers. At SRNL these simulations have been performed using the PORFLOW code as part of Performance Assessments for salt waste disposal and waste tank closure.« less

Alternate paddle configuration for improved wear resistance in the saltstone mixer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reigel, M.; Fowley, M.

The Saltstone Production Facility has a 10-inch Readco-Kurimoto continuous mixer that mixes the premix dry feeds and low-level waste salt solution to make fresh (uncured) saltstone. Inspection of the mixer in January 2013 showed significant wear on the third, fourth and fifth paddle pairs after the conveying augers. A 2-inch Readco-Kurimoto continuous mixer was used to test alternate paddle configurations for use in the 10-inch mixer to decrease the wear rate on the paddles. Two wear tests were conducted to investigate a method of reducing wear on the mixer paddles. The first test (wear test 2a) had a paddle configurationmore » similar to the currently installed 10-inch mixer in the SPF. This test established baseline wear. The second test (wear test 2b) had a reconfigured paddle arrangement that replaced the flat paddles with helical paddles for paddle pairs 2 - 6 and aligned paddle pair 1 with the augers. The intent of the reconfiguration was to more effectively convey the partially wetted dry feeds through the transition region and into the liquid feed where paddle wear is reduced due to dry feeds and salt solution being mixed at the intended water to premix ratio. The design of the helical paddles provides conveyance through the transition region to the liquid feed inlet. The alignment with the auger is aimed to provide a smoother transition (minimizing the discontinuity between the auger and paddle pair 1) into the downstream paddles. A soft metal with low wear resistance (6000 series aluminum) was used for the wear testing paddles to determine wear patterns while minimizing run time and maximizing wear rate. For the two paddle configurations tested using the scaled 2-inch Readco-Kurimoto continuous mixer, with the first six paddles after the augers replaced by the wear paddles and the remaining paddles were stainless steel. Since the 10-inch SPF mixer is designed with the liquid inlet centered over paddle pairs 5 and 6, the scaled 2-inch mixer was configured the same way. The wear rate from wear test 2a was approximately double the wear rate from wear test 2b for paddle pairs 4 and 5. For both configurations, there was little or no wear on paddle pairs 1, 2, 3 and 6 based on mass change, indicating that the un-wetted and fully wetted premix materials cause less wear than the partially wetted premix. Additionally, inspection of the wear surface of the paddles showed more deformation on the flat paddles than the helical paddles which was consistent with the wear rates. Aligning of the auger discharge flight with paddle pair 1 resulted in a lower wear rate paddle pair 1 rather than having them misaligned with the feed augers. During the paddle wear tests, polishing wear was observed on the inside barrel of the mixer. The polishing wear is evident on the upper housing clamshell and the lower housing clamshell primarily at paddle pairs 4 and 5, which is the transition region of the mixer. Wear on the mixer barrel increases the space between the paddles and the barrel, resulting in increased grout build up on the barrel. Since the mixer barrel cannot be reconfigured or replaced in the SPF, the method for mitigating wear on the barrel is to move the more viscous grout through the transition region as quickly as possible. In addition, the location of the liquid inlet does not allow for sufficient cleaning of the mixer since residual grout remains on paddle pairs 1 - 4. As the paddles continue to wear and the self-cleaning capability of the paddles is lost, the lack of sufficient flushing would aid in grout build up between the barrel and the paddles which could eventually lead to decreased throughput capacity of the dry feeds. Changing the paddle configuration from flat to helical resulted in no change to the rheological properties of the grout mixture. Both tests produced a grout that is within the processing range of the SPF. Based on the results of this testing, it is recommended for the currently installed SPF mixer that paddle pairs 1 through 6 be helical rather than flat, with the paddle pair 1 aligned with the feed augers in order to minimize the wear occurring in the SPF mixer. Based on the results of this testing, it is recommended that the mixer be inspected and critical measurements be taken whenever the SPF processing schedule allows in order to establish a wear rate of the 10-inch mixer paddles.5 Based on these measurements, the lifetime of paddles in the transition region can be established in order to set up a maintenance schedule for the mixer. Since replacing the entire mixer is very expensive and time intensive, replacing the worn paddles after a specific time period would allow for planned shutdowns as well as process optimization such that the mixer throughput is not compromised. In addition, further testing should be performed to determine an alternate liquid inlet location to better flush the mixer of residual grout at the end of processing. Sufficiently cleaning the mixer will help eliminate another potential source of wear. Another potential method for reducing the wear rate in the mixer is to reduce the mixer speed without affecting the throughput capacity. Since wear rate is a function of impact velocity of the grout and mixing paddles, testing could be done using the 2-inch mixer determine the optimum mixer speed to reduce wear but not adversely impact facility operations (e.g. throughput capacity and grout properties).« less

NRC Consultation and Monitoring at the Savannah River Site: Focusing Reviews of Two Different Disposal Actions - 12181

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ridge, A. Christianne; Barr, Cynthia S.; Pinkston, Karen E.

Section 3116 of the Ronald W. Reagan National Defense Authorization Act for Fiscal Year 2005 (NDAA) requires the U.S. Department of Energy (DOE) to consult with the U.S. Nuclear Regulatory Commission (NRC) for certain non-high level waste determinations. The NDAA also requires NRC to monitor DOE's disposal actions related to those determinations. In Fiscal Year 2011, the NRC staff reviewed DOE performance assessments for tank closure at the F-Tank Farm (FTF) Facility and salt waste disposal at the Saltstone Disposal Facility (SDF) at the Savannah River Site (SRS) as part of consultation and monitoring, respectively. Differences in inventories, waste forms,more » and key barriers led to different areas of focus in the NRC reviews of these two activities at the SRS. Because of the key role of chemically reducing grouts in both applications, the evaluation of chemical barriers was significant to both reviews. However, radionuclide solubility in precipitated metal oxides is expected to play a significant role in FTF performance whereas release of several key radionuclides from the SDF is controlled by sorption or precipitation within the cementitious wasteform itself. Similarly, both reviews included an evaluation of physical barriers to flow, but differences in the physical configurations of the waste led to differences in the reviews. For example, NRC's review of the FTF focused on the modeled degradation of carbon steel tank liners while the staff's review of the SDF performance included a detailed evaluation of the physical degradation of the saltstone wasteform and infiltration-limiting closure cap. Because of the long time periods considered (i.e., tens of thousands of years), the NRC reviews of both facilities included detailed evaluation of the engineered chemical and physical barriers. The NRC staff reviews of residual waste disposal in the FTF and salt waste disposal in the SDF focused on physical barriers to flow and chemical barriers to radionuclide release from the waste. Because the waste inventory and concentration at both sites is sufficient to generate unacceptable doses to an off-site member of the public or inadvertent intruder in the absence of engineered barriers, the NRC staff review focused on the engineering features DOE plans to put in place to limit radionuclide release. At the FTF, DOE expects that peak doses are delayed beyond a 10,000 year performance period by a combination of (1) the flow-limiting effect of the steel tank liner and (2) chemical conditions created by the stabilizing grout overlying the waste that limit the solubility of key radionuclides for tens of thousands of years. At the SDF, DOE expects that flow will be significantly limited by water shedding along the closure cap lower drainage layer and that radionuclide release will be further limited by radionuclide precipitation or sorption within the high pH, chemically reducing conditions created within the saltstone waste form. Because the performance of both facilities depends on the performance of engineered barriers for thousands of years, the reviews included a detailed evaluation of the expected long-term behavior of these barriers. As previously discussed, NRC staff reviews of DOE waste determinations during consultation are designed to evaluate the three NDAA criteria, whereas the review of an updated PA during monitoring only addresses whether the NRC staff has reasonable assurance that the planned disposal action will meet the performance objectives of 10 CFR Part 61. The NRC staff review of the Waste Determination for the FTF did not include conclusions about whether the planned disposal of residual waste at the FTF would meet the NDAA criteria because of the substantial uncertainties in the degree of waste removal DOE would achieve and other technical uncertainties. The main product of the NRC staff review of the planned FTF disposal action is the recommendation that DOE should conduct waste release experiments to increase support for key modeling assumptions related to: (1) the evolution of pH and Eh in the grouted tank system over time; (2) identification of HRR association with solid phases comprising the residual wastes; and (3) expected solubility of HRRs under a range of environmental or service conditions that the residual wastes in the contaminated zone are expected to be exposed to over time. Implementation of this recommendation is deemed crucial for NRC staff to have reasonable assurance that the performance objectives in 10 CFR Part 61, Subpart C can be met. Given the risk-significance of Tank 18 to the overall PA and the short timeline for closure of this tank, the NRC staff recommended that DOE should initiate discussions with NRC staff regarding implementation of this recommendation for Tank 18 as soon as practical. The NRC staff also recommended that experiments to address this recommendation should be conducted prior to final closure of Tank 18. Results of the Tank 18 residual waste experiments, if conducted, will be evaluated by NRC staff to determine the need for additional data collection, experiments, and modeling for Tank 18, as well as other FTF tanks. Additional information regarding the NRC staff's recommendations in this area, including details on the suggested implementation of other recommendations will be provided in the NRC staff's plan for monitoring the FTF later in FY 2012, after DOE makes a final decision on the waste determination. The NRC staff's review of waste disposal at the SDF is ongoing. When complete, the SDF TER will indicate whether the NRC staff continues to have reasonable assurance that waste disposal at the SDF will meet the performance objectives of 10 CFR Part 61 (NDAA Criterion 3). The TER also will include risk insights that will form the basis of the NRC staff's revised monitoring plan for the SDF. The NRC staff will publish an updated monitoring plan for the SDF later in FY 2012. (authors)« less

Analysis Of 2H-Evaporator Scale Pot Bottom Sample [HTF-13-11-28H

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oji, L. N.

2013-07-15

Savannah River Remediation (SRR) is planning to remove a buildup of sodium aluminosilicate scale from the 2H-evaporator pot by loading and soaking the pot with heated 1.5 M nitric acid solution. Sampling and analysis of the scale material from the 2H evaporator has been performed so that the evaporator can be chemically cleaned beginning July of 2013. Historically, since the operation of the Defense Waste Processing Facility (DWPF), silicon in the DWPF recycle stream combines with aluminum in the typical tank farm supernate to form sodium aluminosilicate scale mineral deposits in the 2H-evaporator pot and gravity drain line. The 2H-evaporatormore » scale samples analyzed by Savannah River National Laboratory (SRNL) came from the bottom cone sections of the 2H-evaporator pot. The sample holder from the 2H-evaporator wall was virtually empty and was not included in the analysis. It is worth noting that after the delivery of these 2H-evaporator scale samples to SRNL for the analyses, the plant customer determined that the 2H evaporator could be operated for additional period prior to requiring cleaning. Therefore, there was no need for expedited sample analysis as was presented in the Technical Task Request. However, a second set of 2H evaporator scale samples were expected in May of 2013, which would need expedited sample analysis. X-ray diffraction analysis (XRD) confirmed the bottom cone section sample from the 2H-evaporator pot consisted of nitrated cancrinite, (a crystalline sodium aluminosilicate solid), clarkeite and uranium oxide. There were also mercury compound XRD peaks which could not be matched and further X-ray fluorescence (XRF) analysis of the sample confirmed the existence of elemental mercury or mercuric oxide. On ''as received'' basis, the scale contained an average of 7.09E+00 wt % total uranium (n = 3; st.dev. = 8.31E-01 wt %) with a U-235 enrichment of 5.80E-01 % (n = 3; st.dev. = 3.96E-02 %). The measured U-238 concentration was 7.05E+00 wt % (n=3, st. dev. = 8.25E-01 wt %). Analyses results for Pu-238 and Pu-239, and Pu-241 are 7.06E-05 {+-} 7.63E-06 wt %, 9.45E-04 {+-} 3.52E-05 wt %, and <2.24E-06 wt %, respectively. These results are provided so that SRR can calculate the equivalent uranium-235 concentrations for the NCSA. Because this 2H evaporator pot bottom scale sample contained a significant amount of elemental mercury (11.7 wt % average), it is recommended that analysis for mercury be included in future Technical Task Requests on 2H evaporator sample analysis at SRNL. Results confirm that the uranium contained in the scale remains depleted with respect to natural uranium. SRNL did not calculate an equivalent U-235 enrichment, which takes into account other fissionable isotopes U-233, Pu-239 and Pu-241.« less

Pilot-scale tests of HEME and HEPA dissolution process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qureshi, Z.H.; Strege, D.K.

A series of pilot-scale demonstration tests for the dissolution of High Efficiency Mist Eliminators (HEME`s) and High Efficiency Particulate Airfilters (HEPA) were performed on a 1/5th linear scale. These fiberglass filters are to be used in the Defense Waste Processing Facility (DWPF) to decontaminate the effluents from the off-gases generated during the feed preparation process and vitrification. When removed, these filters will be dissolved in the Decontamination Waste Treatment Tank (DWTT) using 5 wt% NaOH solution. The contaminated fiberglass is converted to an aqueous stream which will be transferred to the waste tanks. The filter metal structure will be rinsedmore » with process water before its disposal as low-level solid waste. The pilot-scale study reported here successfully demonstrated a simple one step process using 5 wt% NaOH solution. The proposed process requires the installation of a new water spray ring with 30 nozzles. In addition to the reduced waste generated, the total process time is reduced to 48 hours only (66% saving in time). The pilot-scale tests clearly demonstrated that the dissolution process of HEMEs has two stages - chemical digestion of the filter and mechanical erosion of the digested filter. The digestion is achieved by a boiling 5 wt% caustic solutions, whereas the mechanical break down of the digested filter is successfully achieved by spraying process water on the digested filter. An alternate method of breaking down the digested filter by increased air sparging of the solution was found to be marginally successful are best. The pilot-scale tests also demonstrated that the products of dissolution are easily pumpable by a centrifugal pump.« less

Automatic detection of blood versus non-blood regions on intravascular ultrasound (IVUS) images using wavelet packet signatures

NASA Astrophysics Data System (ADS)

Katouzian, Amin; Baseri, Babak; Konofagou, Elisa E.; Laine, Andrew F.

2008-03-01

Intravascular ultrasound (IVUS) has been proven a reliable imaging modality that is widely employed in cardiac interventional procedures. It can provide morphologic as well as pathologic information on the occluded plaques in the coronary arteries. In this paper, we present a new technique using wavelet packet analysis that differentiates between blood and non-blood regions on the IVUS images. We utilized the multi-channel texture segmentation algorithm based on the discrete wavelet packet frames (DWPF). A k-mean clustering algorithm was deployed to partition the extracted textural features into blood and non-blood in an unsupervised fashion. Finally, the geometric and statistical information of the segmented regions was used to estimate the closest set of pixels to the lumen border and a spline curve was fitted to the set. The presented algorithm may be helpful in delineating the lumen border automatically and more reliably prior to the process of plaque characterization, especially with 40 MHz transducers, where appearance of the red blood cells renders the border detection more challenging, even manually. Experimental results are shown and they are quantitatively compared with manually traced borders by an expert. It is concluded that our two dimensional (2-D) algorithm, which is independent of the cardiac and catheter motions performs well in both in-vivo and in-vitro cases.

Geochemical Data Package for Performance Assessment Calculations Related to the Savannah River Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaplan, Daniel I.

The Savannah River Site (SRS) disposes of low-level radioactive waste (LLW) and stabilizes high-level radioactive waste (HLW) tanks in the subsurface environment. Calculations used to establish the radiological limits of these facilities are referred to as Performance Assessments (PA), Special Analyses (SA), and Composite Analyses (CA). The objective of this document is to revise existing geochemical input values used for these calculations. This work builds on earlier compilations of geochemical data (2007, 2010), referred to a geochemical data packages. This work is being conducted as part of the on-going maintenance program of the SRS PA programs that periodically updates calculationsmore » and data packages when new information becomes available. Because application of values without full understanding of their original purpose may lead to misuse, this document also provides the geochemical conceptual model, the approach used for selecting the values, the justification for selecting data, and the assumptions made to assure that the conceptual and numerical geochemical models are reasonably conservative (i.e., bias the recommended input values to reflect conditions that will tend to predict the maximum risk to the hypothetical recipient). This document provides 1088 input parameters for geochemical parameters describing transport processes for 64 elements (>740 radioisotopes) potentially occurring within eight subsurface disposal or tank closure areas: Slit Trenches (ST), Engineered Trenches (ET), Low Activity Waste Vault (LAWV), Intermediate Level (ILV) Vaults, Naval Reactor Component Disposal Areas (NRCDA), Components-in-Grout (CIG) Trenches, Saltstone Facility, and Closed Liquid Waste Tanks. The geochemical parameters described here are the distribution coefficient, Kd value, apparent solubility concentration, k s value, and the cementitious leachate impact factor.« less

Saltstone SDU6 Modeling Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Si Y.; Hyun, Sinjae

2013-01-10

A new disposal unit, designated as Saltstone Disposal Unit 6 (SDU6), is being designed for support of site accelerated closure goals and salt waste projections identified in the new Liquid Waste System Plan. The unit is a cylindrical disposal cell of 375 ft in diameter and 43 ft in height, and it has a minimum 30 million gallons of capacity. SRNL was requested to evaluate the impact of an increased grout placement height on the flow patterns radially spread on the floor and to determine whether grout quality is impacted by the height. The primary goals of the work aremore » to develop the baseline Computational Fluid Dynamics (CFD) model and to perform the evaluations for the flow patterns of grout material in SDU6 as a function of elevation of grout discharge port and grout rheology. Two transient grout models have been developed by taking a three-dimensional multiphase CFD approach to estimate the domain size of the grout materials radially spread on the facility floor and to perform the sensitivity analysis with respect to the baseline design and operating conditions such as elevation height of the discharge port and fresh grout properties. For the CFD modeling calculations, air-grout Volume of Fluid (VOF) method combined with Bingham plastic and time-dependent grout models were used for examining the impact of fluid spread performance for the initial baseline configurations and to evaluate the impact of grout pouring height on grout quality. The grout quality was estimated in terms of the air volume fraction for the grout layer formed on the SDU6 floor, resulting in the change of grout density. The study results should be considered as preliminary scoping analyses since benchmarking analysis is not included in this task scope. Transient analyses with the Bingham plastic model were performed with the FLUENTTM code on the high performance parallel computing platform in SRNL. The analysis coupled with a transient grout aging model was performed by using ANSYS-CFX code in the parallel computing platform in Mercer University. Recommended operational guidance was developed assuming that local shear rates and flow patterns related to radial spread along the SDU floor can be used as a measure of grout performance and spatial dispersion affected by the grout height and viscosity. The 5 ft height baseline results show that when the 150 gpm grout flow with a 5 Pa yield stress and a 60 cp viscosity is poured down through a 3 inch discharge port, the grout is spread radially up to about 64 ft distance from the pouring center after 2 hours' pouring time. The air volume fraction of the grout layer is about 29% at 5 minutes' transient time, and it is reduced by about 9% in 2 hours' pouring time, resulting in the grout density consisting of about 80% grout and 20% air volume fractions. The sensitivity results show that when the discharge port is located at a higher position, a larger amount of air is trapped inside the layer formed below the discharge port at the early transient time of less than 30 minutes because of the higher impinging momentum of the grout flow on the floor, resulting in the formation of less smooth layer. The results clearly indicate that the radial spread for the 43 ft discharge port is about 10% faster than that of the 5 ft discharge port for the early transient period of 5 minutes. However, for the pouring time longer than half an hour, the discharge port height does not affect the radial distance spread on the disposal floor. When grout quality is related to grout volume fraction, the grout volume fraction for the 43 ft discharge port has lower volume fraction than the 5 ft discharge port for the transient period of the first 5 minutes. However, for the pouring time longer than half an hour, the discharge port height does not affect the grout volume fraction for the layer accumulated on the disposal floor. A modified Bingham plastic model coupled with time-dependent viscosity behavior was developed for conducting the initial scoping calculations to assess the impact of fluid residence time on radial spreading and basic flow patterns. The results for the transient viscosity model show that when grout material becomes more viscous, the thickness of the grout layer accumulated on the floor becomes higher, but the radial distance spread on the horizontal floor becomes smaller. The early transient results for the grout density with about 32% air volume fractions are in reasonable agreement with those of the idealized Bingham plastic model. It is recommended that the current models developed here be benchmarked against the experimental results for critical applications of the modeling results.« less

THE HYDROTHERMAL REACTIONS OF MONOSODIUM TITANATE, CRYSTALLINE SILICOTITANATE AND SLUDGE IN THE MODULAR SALT PROCESS: A LITERATURE SURVEY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fondeur, F.; Pennebaker, F.; Fink, S.

2010-11-11

The use of crystalline silicotitanate (CST) is proposed for an at-tank process to treat High Level Waste at the Savannah River Site. The proposed configuration includes deployment of ion exchange columns suspended in the risers of existing tanks to process salt waste without building a new facility. The CST is available in an engineered form, designated as IE-911-CW, from UOP. Prior data indicates CST has a proclivity to agglomerate from deposits of silica rich compounds present in the alkaline waste solutions. This report documents the prior literature and provides guidance for the design and operations that include CST to mitigatemore » that risk. The proposed operation will also add monosodium titanate (MST) to the supernate of the tank prior to the ion exchange operation to remove strontium and select alpha-emitting actinides. The cesium loaded CST is ground and then passed forward to the sludge washing tank as feed to the Defense Waste Processing Facility (DWPF). Similarly, the MST will be transferred to the sludge washing tank. Sludge processing includes the potential to leach aluminum from the solids at elevated temperature (e.g., 65 C) using concentrated (3M) sodium hydroxide solutions. Prior literature indicates that both CST and MST will agglomerate and form higher yield stress slurries with exposure to elevated temperatures. This report assessed that data and provides guidance on minimizing the impact of CST and MST on sludge transfer and aluminum leaching sludge.« less

Analysis of Tank 13H (HTF-13-14-156, 157) Surface and Subsurface Supernatant Samples in Support of Enrichment Control, Corrosion Control and Sodium Aluminosilicate Formation Potential Programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oji, L. N.

2015-02-18

The 2H Evaporator system includes mainly Tank 43H (feed tank) and Tank 38H (drop tank) with Tank 22H acting as the DWPF recycle receipt tank. The Tank 13H is being characterized to ensure that it can be transferred to the 2H evaporator. This report provides the results of analyses on Tanks 13H surface and subsurface supernatant liquid samples to ensure compliance with the Enrichment Control Program (ECP), the Corrosion Control Program and Sodium Aluminosilicate Formation Potential in the Evaporator. The U-235 mass divided by the total uranium averaged 0.00799 (0.799 % uranium enrichment) for both the surface and subsurface Tankmore » 13H samples. This enrichment is slightly above the enrichment for Tanks 38H and 43H, where the enrichment normally ranges from 0.59 to 0.7 wt%. The U-235 concentration in Tank 13H samples ranged from 2.01E-02 to 2.63E-02 mg/L, while the U-238 concentration in Tank 13H ranged from 2.47E+00 to 3.21E+00 mg/L. Thus, the U-235/total uranium ratio is in line with the prior 2H-evaporator ECP samples. Measured sodium and silicon concentrations averaged, respectively, 2.46 M and 1.42E-04 M (3.98 mg/L) in the Tank 13H subsurface sample. The measured aluminum concentration in Tanks 13H subsurface samples averaged 2.01E-01 M.« less

Commercial Submersible Mixing Pump For SRS Tank Waste Removal - 15223

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hubbard, Mike; Herbert, James E.; Scheele, Patrick W.

The Savannah River Site Tank Farms have 45 active underground waste tanks used to store and process nuclear waste materials. There are 4 different tank types, ranging in capacity from 2839 m 3 to 4921 m 3 (750,000 to 1,300,000 gallons). Eighteen of the tanks are older style and do not meet all current federal standards for secondary containment. The older style tanks are the initial focus of waste removal efforts for tank closure and are referred to as closure tanks. Of the original 51 underground waste tanks, six of the original 24 older style tanks have completed waste removalmore » and are filled with grout. The insoluble waste fraction that resides within most waste tanks at SRS requires vigorous agitation to suspend the solids within the waste liquid in order to transfer this material for eventual processing into glass filled canisters at the Defense Waste Processing Facility (DWPF). SRS suspends the solid waste by use of recirculating mixing pumps. Older style tanks generally have limited riser openings which will not support larger mixing pumps, since the riser access is typically 58.4 cm (23 inches) in diameter. Agitation for these tanks has been provided by four long shafted standard slurry pumps (SLP) powered by an above tank 112KW (150 HP) electric motor. The pump shaft is lubricated and cooled in a pressurized water column that is sealed from the surrounding waste in the tank. Closure of four waste tanks has been accomplished utilizing long shafted pump technology combined with heel removal using multiple technologies. Newer style waste tanks at SRS have larger riser openings, allowing the processing of waste solids to be accomplished with four large diameter SLPs equipped with 224KW (300 HP) motors. These tanks are used to process the waste from closure tanks for DWPF. In addition to the SLPs, a 224KW (300 HP) submersible mixer pump (SMP) has also been developed and deployed within older style tanks. The SMPs are product cooled and product lubricated canned motor pumps designed to fit within available risers and have significant agitation capabilities to suspend waste solids. Waste removal and closure of two tanks has been accomplished with agitation provided by 3 SMPs installed within the tanks. In 2012, a team was assembled to investigate alternative solids removal technologies to support waste removal for closing tanks. The goal of the team was to find a more cost effective approach that could be used to replace the current mixing pump technology. This team was unable to identify an alternative technology outside of mixing pumps to support waste agitation and removal from SRS waste tanks. However, the team did identify a potentially lower cost mixing pump compared to the baseline SLPs and SMPs. Rather than using the traditional procurement using an engineering specification, the team proposed to seek commercially available submersible mixer pumps (CSMP) as alternatives to SLPs and SMPs. SLPs and SMPs have a high procurement cost and the actual cost of moving pumps between tanks has shown to be significantly higher than the original estimates that justified the reuse of SMPs and SLPs. The team recommended procurement of “off-the-shelf” industry pumps which may be available for significant savings, but at an increased risk of failure and reduced operating life in the waste tank. The goal of the CSMP program is to obtain mixing pumps that could mix from bulk waste removal through tank closure and then be abandoned in place as part of tank closure. This paper will present the development, progress and relative advantages of the CSMP.« less

Analysis Of 2H-Evaporator Scale Wall [HTF-13-82] And Pot Bottom [HTF-13-77] Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oji, L. N.

2013-09-11

Savannah River Remediation (SRR) is planning to remove a buildup of sodium aluminosilicate scale from the 2H-evaporator pot by loading and soaking the pot with heated 1.5 M nitric acid solution. Sampling and analysis of the scale material has been performed so that uranium and plutonium isotopic analysis can be input into a Nuclear Criticality Safety Assessment (NCSA) for scale removal by chemical cleaning. Historically, since the operation of the Defense Waste Processing Facility (DWPF), silicon in the DWPF recycle stream combines with aluminum in the typical tank farm supernate to form sodium aluminosilicate scale mineral deposits in the 2H-evaporatormore » pot and gravity drain line. The 2H-evaporator scale samples analyzed by Savannah River National Laboratory (SRNL) came from two different locations within the evaporator pot; the bottom cone sections of the 2H-evaporator pot [Sample HTF-13-77] and the wall 2H-evaporator [sample HTF-13-82]. X-ray diffraction analysis (XRD) confirmed that both the 2H-evaporator pot scale and the wall samples consist of nitrated cancrinite (a crystalline sodium aluminosilicate solid) and clarkeite (a uranium oxyhydroxide mineral). On ''as received'' basis, the bottom pot section scale sample contained an average of 2.59E+00 {+-} 1.40E-01 wt % total uranium with a U-235 enrichment of 6.12E-01 {+-} 1.48E-02 %, while the wall sample contained an average of 4.03E+00 {+-} 9.79E-01 wt % total uranium with a U-235 enrichment of 6.03E-01% {+-} 1.66E-02 wt %. The bottom pot section scale sample analyses results for Pu-238, Pu-239, and Pu-241 are 3.16E-05 {+-} 5.40E-06 wt %, 3.28E-04 {+-} 1.45E-05 wt %, and <8.80E-07 wt %, respectively. The evaporator wall scale samples analysis values for Pu-238, Pu-239, and Pu-241 averages 3.74E-05 {+-} 6.01E-06 wt %, 4.38E-04 {+-} 5.08E-05 wt %, and <1.38E-06 wt %, respectively. The Pu-241 analyses results, as presented, are upper limit values. For these two evaporator scale samples obtained at two different locations within the evaporator pot the major radioactive components (on a mass basis) in the additional radionuclide analyses were Sr-90, Cs-137 Np-237, Pu-239/240 and Th-232. Small quantities of americium and curium were detected in the blanks used for Am/Cm method for these radionuclides. These trace radionuclide amounts are assumed to come from airborne contamination in the shielded cells drying or digestion oven, which has been replaced. Therefore, the Am/Cm results, as presented, may be higher than the true Am/Cm values for these samples. These results are provided so that SRR can calculate the equivalent uranium-235 concentrations for the NCSA. Results confirm that the uranium contained in the scale remains depleted with respect to natural uranium. SRNL did not calculate an equivalent U-235 enrichment, which takes into account other fissionable isotopes U-233, Pu-239 and Pu-241. The applicable method for calculation of equivalent U-235 will be determined in the NCSA. With a few exceptions, a comparison of select radionuclides measurements from this 2013 2H evaporator scale characterization (pot bottom and wall scale samples) with those measurements for the same radionuclides in the 2010 2H evaporator scale analysis shows that the radionuclide analysis for both years are fairly comparable; the analyses results are about the same order of magnitude.« less

Coupling of Nuclear Waste Form Corrosion and Radionuclide Transports in Presence of Relevant Repository Sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wall, Nathalie A.; Neeway, James J.; Qafoku, Nikolla P.

2015-09-30

Assessments of waste form and disposal options start with the degradation of the waste forms and consequent mobilization of radionuclides. Long-term static tests, single-pass flow-through tests, and the pressurized unsaturated flow test are often employed to study the durability of potential waste forms and to help create models that predict their durability throughout the lifespan of the disposal site. These tests involve the corrosion of the material in the presence of various leachants, with different experimental designs yielding desired information about the behavior of the material. Though these tests have proved instrumental in elucidating various mechanisms responsible for material corrosion,more » the chemical environment to which the material is subject is often not representative of a potential radioactive waste repository where factors such as pH and leachant composition will be controlled by the near-field environment. Near-field materials include, but are not limited to, the original engineered barriers, their resulting corrosion products, backfill materials, and the natural host rock. For an accurate performance assessment of a nuclear waste repository, realistic waste corrosion experimental data ought to be modeled to allow for a better understanding of waste form corrosion mechanisms and the effect of immediate geochemical environment on these mechanisms. Additionally, the migration of radionuclides in the resulting chemical environment during and after waste form corrosion must be quantified and mechanisms responsible for migrations understood. The goal of this research was to understand the mechanisms responsible for waste form corrosion in the presence of relevant repository sediments to allow for accurate radionuclide migration quantifications. The rationale for this work is that a better understanding of waste form corrosion in relevant systems will enable increased reliance on waste form performance in repository environments and potentially decrease the need for expensive engineered barriers.Our current work aims are 1) quantifying and understanding the processes associated with glass alteration in contact with Fe-bearing materials; 2) quantifying and understanding the processes associated with glass alteration in presence of MgO (example of engineered barrier used in WIPP); 3) identifying glass alteration suppressants and the processes involved to reach glass alteration suppression; 4) quantifying and understanding the processes associated with Saltstone and Cast Stone (SRS and Hanford cementitious waste forms) in various representative groundwaters; 5) investigating positron annihilation as a new tool for the study of glass alteration; and 6) quantifying and understanding the processes associated with glass alteration under gamma irradiation.« less

SOLIDIFICATION OF THE HANFORD LAW WASTE STREAM PRODUCED AS A RESULT OF NEAR-TANK CONTINUOUS SLUDGE LEACHING AND SODIUM HYDROXIDE RECOVERY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reigel, M.; Johnson, F.; Crawford, C.

2011-09-20

The U.S. Department of Energy (DOE), Office of River Protection (ORP), is responsible for the remediation and stabilization of the Hanford Site tank farms, including 53 million gallons of highly radioactive mixed wasted waste contained in 177 underground tanks. The plan calls for all waste retrieved from the tanks to be transferred to the Waste Treatment Plant (WTP). The WTP will consist of three primary facilities including pretreatment facilities for Low Activity Waste (LAW) to remove aluminum, chromium and other solids and radioisotopes that are undesirable in the High Level Waste (HLW) stream. Removal of aluminum from HLW sludge canmore » be accomplished through continuous sludge leaching of the aluminum from the HLW sludge as sodium aluminate; however, this process will introduce a significant amount of sodium hydroxide into the waste stream and consequently will increase the volume of waste to be dispositioned. A sodium recovery process is needed to remove the sodium hydroxide and recycle it back to the aluminum dissolution process. The resulting LAW waste stream has a high concentration of aluminum and sodium and will require alternative immobilization methods. Five waste forms were evaluated for immobilization of LAW at Hanford after the sodium recovery process. The waste forms considered for these two waste streams include low temperature processes (Saltstone/Cast stone and geopolymers), intermediate temperature processes (steam reforming and phosphate glasses) and high temperature processes (vitrification). These immobilization methods and the waste forms produced were evaluated for (1) compliance with the Performance Assessment (PA) requirements for disposal at the IDF, (2) waste form volume (waste loading), and (3) compatibility with the tank farms and systems. The iron phosphate glasses tested using the product consistency test had normalized release rates lower than the waste form requirements although the CCC glasses had higher release rates than the quenched glasses. However, the waste form failed to meet the vapor hydration test criteria listed in the WTP contract. In addition, the waste loading in the phosphate glasses were not as high as other candidate waste forms. Vitrification of HLW waste as borosilicate glass is a proven process; however the HLW and LAW streams at Hanford can vary significantly from waste currently being immobilized. The ccc glasses show lower release rates for B and Na than the quenched glasses and all glasses meet the acceptance criterion of < 4 g/L. Glass samples spiked with Re{sub 2}O{sub 7} also passed the PCT test. However, further vapor hydration testing must be performed since all the samples cracked and the test could not be performed. The waste loading of the iron phosphate and borosilicate glasses are approximately 20 and 25% respectively. The steam reforming process produced the predicted waste form for both the high and low aluminate waste streams. The predicted waste loadings for the monolithic samples is approximately 39%, which is higher than the glass waste forms; however, at the time of this report, no monolithic samples were made and therefore compliance with the PA cannot be determined. The waste loading in the geopolymer is approximately 40% but can vary with the sodium hydroxide content in the waste stream. Initial geopolymer mixes revealed compressive strengths that are greater than 500 psi for the low aluminate mixes and less than 500 psi for the high aluminate mixes. Further work testing needs to be performed to formulate a geopolymer waste form made using a high aluminate salt solution. A cementitious waste form has the advantage that the process is performed at ambient conditions and is a proven process currently in use for LAW disposal. The Saltstone/Cast Stone formulated using low and high aluminate salt solutions retained at least 97% of the Re that was added to the mix as a dopant. While this data is promising, additional leaching testing must be performed to show compliance with the PA. Compressive strength tests must also be performed on the Cast Stone monoliths to verify PA compliance. Based on testing performed for this report, the borosilicate glass and Cast Stone are the recommended waste forms for further testing. Both are proven technologies for radioactive waste disposal and the initial testing using simulated Hanford LAW waste shows compliance with the PA. Both are resistant to leaching and have greater than 25% waste loading.« less

FY13 GLYCOLIC-NITRIC ACID FLOWSHEET DEMONSTRATIONS OF THE DWPF CHEMICAL PROCESS CELL WITH SIMULANTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D.; Zamecnik, J.; Best, D.

Savannah River Remediation is evaluating changes to its current Defense Waste Processing Facility flowsheet to replace formic acid with glycolic acid in order to improve processing cycle times and decrease by approximately 100x the production of hydrogen, a potentially flammable gas. Higher throughput is needed in the Chemical Processing Cell since the installation of the bubblers into the melter has increased melt rate. Due to the significant maintenance required for the safety significant gas chromatographs and the potential for production of flammable quantities of hydrogen, eliminating the use of formic acid is highly desirable. Previous testing at the Savannah Rivermore » National Laboratory has shown that replacing formic acid with glycolic acid allows the reduction and removal of mercury without significant catalytic hydrogen generation. Five back-to-back Sludge Receipt and Adjustment Tank (SRAT) cycles and four back-to-back Slurry Mix Evaporator (SME) cycles were successful in demonstrating the viability of the nitric/glycolic acid flowsheet. The testing was completed in FY13 to determine the impact of process heels (approximately 25% of the material is left behind after transfers). In addition, back-to-back experiments might identify longer-term processing problems. The testing was designed to be prototypic by including sludge simulant, Actinide Removal Product simulant, nitric acid, glycolic acid, and Strip Effluent simulant containing Next Generation Solvent in the SRAT processing and SRAT product simulant, decontamination frit slurry, and process frit slurry in the SME processing. A heel was produced in the first cycle and each subsequent cycle utilized the remaining heel from the previous cycle. Lower SRAT purges were utilized due to the low hydrogen generation. Design basis addition rates and boilup rates were used so the processing time was shorter than current processing rates.« less

Report of the oversight assessment of the operational readiness review of the Savannah River Site Defense Waste Processing Facility Cold Chemical Runs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, B.

1993-03-01

This report presents the results of an oversight assessment (OA) conducted by the US Department of Energy's (DOE) Office of Environment, Safety and Health (EH) of the operational readiness review (ORR) activities for the Cold Chemical Runs (CCRs) at the Defense Waste Processing Facility (DWPF) located at Savannah River Site (SRS). The EH OA of this facility took place concurrently with an ORR performed by the DOE Office of Environmental Restoration and Waste Management (EM). The EM ORR was conducted from September 28, 1992, through October 9, 1992, although portions of the EM ORR were extended beyond this period. Themore » EH OA evaluated the comprehensiveness and effectiveness of the EM ORR. The EH OA was designed to ascertain whether the EM ORR was thorough and demonstrated sufficient inquisitiveness to verify that the implementation of programs and procedures is adequate to assure the protection of worker safety and health. The EH OA was carried out in accordance with the protocol and procedures of the EH Program for Oversight Assessment of Operational Readiness Evaluations for Startups and Restarts,'' dated September 15, 1992. Based on its OA and verification of the resolution of EH OA findings, the EH OA Team believes that the startup of the CCRs may be safely begun, pending satisfactory completion and verification of the prestart findings identified by the EM ORR. The EH OA was based primarily on an evaluation of the comprehensiveness and effectiveness of the EM ORR and addressed the following areas: industrial safety, industrial hygiene, and respiratory protection; fire protection; and chemical safety. The EH OA conducted independent vertical-slice'' reviews to confirm EM ORR results in the areas of confined-space entry, respiratory protection, fire protection, and chemical safety.« less

SCM Paste Samples Exposed To Aggressive Solutions. Cementitious Barriers Partnership

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foster, T.

This report summarizes experimental work performed by SIMCO Technologies Inc. (SIMCO) as part of the Cementitious Barriers Partnership (CBP) project. The test series followed an experimental program dedicated to the study of ordinary Portland cement (OPC) hydrated cement pastes exposed to aggressive solutions. In the present study, the scope is extended to hydrated cement pastes incorporating supplementary cementitious materials (SCM) such as fly ash and ground granulated blast furnace slag (GGBFS). Also, the range of aggressive contact solutions was expanded. The experimental program aimed at testing aggressive contact solutions that more closely mimic the chemical composition of saltstone pore solution.more » Five different solutions, some of which incorporated high levels of carbonate and nitrate, were placed in contact with four different hydrated cement paste mixes. In all solutions, 150 mmol/L of SO 4 2– (14 400 ppm) were present. The solutions included different pH conditions and different sodium content. Two paste mixes were equivalent to Vault 1/4 and Vault 2 concrete mixes used at SRS in storage structures. Two additional paste mixes, cast at the same water-to-cement ratio and using the same cements but without SCMs, were also tested. The damage evolution in samples was monitored using ultrasonic pulse velocity (UPV) and mass measurements. After three and twelve months of exposure conditions, samples were taken out of solution containers and analyzed to perform migration tests and porosity measurements. Globally, results were in line with the previous study and confirmed that high pH may limit the formation of some deleterious phases like gypsum. In this case, ettringite may form but is not necessarily associated with damage. However, the high concentration of sodium may be associated with the formation of an AFm-like mineral called U-phase. The most significant evidences of damage were all associated with the Vault 2 paste analog. This material proved very sensitive to high pH. All measurement techniques used to monitor and evaluate damage to samples indicated significant alterations to this mix when immersed in contact solutions containing sodium hydroxide. It was hypothesized that the low cement content, combined with high silica content coming from silica fume, fly ash and GGBFS led to the presence unreacted silica. It is possible that the pozzolanic reaction of these SCMs could not be activated due to the low alkali content, a direct consequence of low cement content. In this scenario, the material end up having a lot of silica available to react upon contact with sodium hydroxide, possibly forming a gel that may be similar to the gel formed in alkali-silica reactions. This scenario needs further experimental confirmation, but it may well explain the poor behavior of mix PV2 in presence of NaOH.« less

Final Report - Crystal Settling, Redox, and High Temperature Properties of ORP HLW and LAW Glasses, VSL-09R1510-1, Rev. 0, dated 6/18/09

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.; Wang, C.; Gan, H.

2013-11-13

The radioactive tank waste treatment programs at the U. S. Department of Energy (DOE) have featured joule heated ceramic melter technology for the vitrification of high level waste (HLW). The Hanford Tank Waste Treatment and Immobilization Plant (WTP) employs this same basic technology not only for the vitrification of HLW streams but also for the vitrification of Low Activity Waste (LAW) streams. Because of the much greater throughput rates required of the WTP as compared to the vitrification facilities at the West Valley Demonstration Project (WVDP) or the Defense Waste Processing Facility (DWPF), the WTP employs advanced joule heated meltersmore » with forced mixing of the glass pool (bubblers) to improve heat and mass transport and increase melting rates. However, for both HLW and LAW treatment, the ability to increase waste loadings offers the potential to significantly reduce the amount of glass that must be produced and disposed and, therefore, the overall project costs. This report presents the results from a study to investigate several glass property issues related to WTP HLW and LAW vitrification: crystal formation and settling in selected HLW glasses; redox behavior of vanadium and chromium in selected LAW glasses; and key high temperature thermal properties of representative HLW and LAW glasses. The work was conducted according to Test Plans that were prepared for the HLW and LAW scope, respectively. One part of this work thus addresses some of the possible detrimental effects due to considerably higher crystal content in waste glass melts and, in particular, the impact of high crystal contents on the flow property of the glass melt and the settling rate of representative crystalline phases in an environment similar to that of an idling glass melter. Characterization of vanadium redox shifts in representative WTP LAW glasses is the second focal point of this work. The third part of this work focused on key high temperature thermal properties of representative WTP HLW and LAW glasses over a wide range of temperatures, from the melter operating temperature to the glass transition.« less

SUMMARY OF 2010 DOE EM INTERNATIONAL PROGRAM STUDIES OF WASTE GLASS STRUCTURE AND PROPERTIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, K.; Choi, A.; Marra, J.

2011-02-07

Collaborative work between the Savannah River National Laboratory (SRNL) and SIA Radon in Russia was divided among three tasks for calendar year 2010. The first task focused on the study of simplified high level waste glass compositions with the objective of identifying the compositional drivers that lead to crystallization and poor chemical durability. The second task focused on detailed characterization of more complex waste glass compositions with unexpectedly poor chemical durabilities. The third task focused on determining the structure of select high level waste glasses made with varying frit compositions in order to improve models under development for predicting themore » melt rate of the Defense Waste Processing Facility (DWPF) glasses. The majority of these tasks were carried out at SIA Radon. Selection and fabrication of the glass compositions, along with chemical composition measurements and evaluations of durability were carried out at SRNL and are described in this report. SIA Radon provided three summary reports based on the outcome of the three tasks. These reports are included as appendices to this document. Briefly, the result of characterization of the Task 1 glasses may indicate that glass compositions where iron is predominantly tetrahedrally coordinated have more of a tendency to crystallize nepheline or nepheline-like phases. For the Task 2 glasses, the results suggested that the relatively low fraction of tetrahedrally coordinated boron and the relatively low concentrations of Al{sub 2}O{sub 3} available to form [BO{sub 4/2}]{sup -}Me{sup +} and [AlO{sub 4/2}]{sup -}Me{sup +} tetrahedral units are not sufficient to consume all of the alkali ions, and thus these alkali ions are easily leached from the glasses. All of the twelve Task 3 glass compositions were determined to be mainly amorphous, with some minor spinel phases. Several key structural units such as metasilicate chains and rings were identified, which confirms the current modeling approach for the silicate phase. The coordination of aluminum and iron was found to be mainly tetrahedral, with some octahedral iron ions. In all samples, trigonally-coordinated boron was determined to dominate over tetrahedrally-coordinated boron. The results further suggested that BO{sub 4} tetrahedra and BO{sub 3} triangles form complex borate units and may be present as separate constituents. However, no quantification of tetrahedral-to-trigonal boron ratio was made.« less

CBP Toolbox Version 3.0 “Beta Testing” Performance Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, III, F. G.

2016-07-29

One function of the Cementitious Barriers Partnership (CBP) is to assess available models of cement degradation and to assemble suitable models into a “Toolbox” that would be made available to members of the partnership, as well as the DOE Complex. To this end, SRNL and Vanderbilt University collaborated to develop an interface using the GoldSim software to the STADIUM @ code developed by SIMCO Technologies, Inc. and LeachXS/ORCHESTRA developed by Energy research Centre of the Netherlands (ECN). Release of Version 3.0 of the CBP Toolbox is planned in the near future. As a part of this release, an increased levelmore » of quality assurance for the partner codes and the GoldSim interface has been developed. This report documents results from evaluation testing of the ability of CBP Toolbox 3.0 to perform simulations of concrete degradation applicable to performance assessment of waste disposal facilities. Simulations of the behavior of Savannah River Saltstone Vault 2 and Vault 1/4 concrete subject to sulfate attack and carbonation over a 500- to 1000-year time period were run using a new and upgraded version of the STADIUM @ code and the version of LeachXS/ORCHESTRA released in Version 2.0 of the CBP Toolbox. Running both codes allowed comparison of results from two models which take very different approaches to simulating cement degradation. In addition, simulations of chloride attack on the two concretes were made using the STADIUM @ code. The evaluation sought to demonstrate that: 1) the codes are capable of running extended realistic simulations in a reasonable amount of time; 2) the codes produce “reasonable” results; the code developers have provided validation test results as part of their code QA documentation; and 3) the two codes produce results that are consistent with one another. Results of the evaluation testing showed that the three criteria listed above were met by the CBP partner codes. Therefore, it is concluded that the codes can be used to support performance assessment. This conclusion takes into account the QA documentation produced for the partner codes and for the CBP Toolbox.« less

The Cementitious Barriers Partnership (CBP) Software Toolbox Capabilities in Assessing the Degradation of Cementitious Barriers - 13487

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flach, G.P.; Burns, H.H.; Langton, C.

2013-07-01

The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the U.S. Department of Energy (US DOE) Office of Tank Waste and Nuclear Materials Management. The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that help improve understanding and predictions of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. Tools selected for and developed under this program have been used to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance up tomore » 100 years and longer for operating facilities and longer than 1000 years for waste disposal. The CBP Software Toolbox has produced tangible benefits to the DOE Performance Assessment (PA) community. A review of prior DOE PAs has provided a list of potential opportunities for improving cementitious barrier performance predictions through the use of the CBP software tools. These opportunities include: 1) impact of atmospheric exposure to concrete and grout before closure, such as accelerated slag and Tc-99 oxidation, 2) prediction of changes in K{sub d}/mobility as a function of time that result from changing pH and redox conditions, 3) concrete degradation from rebar corrosion due to carbonation, 4) early age cracking from drying and/or thermal shrinkage and 5) degradation due to sulfate attack. The CBP has already had opportunity to provide near-term, tangible support to ongoing DOE-EM PAs such as the Savannah River Saltstone Disposal Facility (SDF) by providing a sulfate attack analysis that predicts the extent and damage that sulfate ingress will have on the concrete vaults over extended time (i.e., > 1000 years). This analysis is one of the many technical opportunities in cementitious barrier performance that can be addressed by the DOE-EM sponsored CBP software tools. Modification of the existing tools can provide many opportunities to bring defense in depth in prediction of the performance of cementitious barriers over time. (authors)« less

Report of the oversight assessment of the operational readiness review of the Savannah River Site Defense Waste Processing Facility Cold Chemical Runs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, B.

1993-03-01

This report presents the results of an oversight assessment (OA) conducted by the US Department of Energy`s (DOE) Office of Environment, Safety and Health (EH) of the operational readiness review (ORR) activities for the Cold Chemical Runs (CCRs) at the Defense Waste Processing Facility (DWPF) located at Savannah River Site (SRS). The EH OA of this facility took place concurrently with an ORR performed by the DOE Office of Environmental Restoration and Waste Management (EM). The EM ORR was conducted from September 28, 1992, through October 9, 1992, although portions of the EM ORR were extended beyond this period. Themore » EH OA evaluated the comprehensiveness and effectiveness of the EM ORR. The EH OA was designed to ascertain whether the EM ORR was thorough and demonstrated sufficient inquisitiveness to verify that the implementation of programs and procedures is adequate to assure the protection of worker safety and health. The EH OA was carried out in accordance with the protocol and procedures of the ``EH Program for Oversight Assessment of Operational Readiness Evaluations for Startups and Restarts,`` dated September 15, 1992. Based on its OA and verification of the resolution of EH OA findings, the EH OA Team believes that the startup of the CCRs may be safely begun, pending satisfactory completion and verification of the prestart findings identified by the EM ORR. The EH OA was based primarily on an evaluation of the comprehensiveness and effectiveness of the EM ORR and addressed the following areas: industrial safety, industrial hygiene, and respiratory protection; fire protection; and chemical safety. The EH OA conducted independent ``vertical-slice`` reviews to confirm EM ORR results in the areas of confined-space entry, respiratory protection, fire protection, and chemical safety.« less

NRC Monitoring of Salt Waste Disposal at the Savannah River Site - 13147

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pinkston, Karen E.; Ridge, A. Christianne; Alexander, George W.

2013-07-01

As part of monitoring required under Section 3116 of the Ronald W. Reagan National Defense Authorization Act for Fiscal Year 2005 (NDAA), the NRC staff reviewed an updated DOE performance assessment (PA) for salt waste disposal at the Saltstone Disposal Facility (SDF). The NRC staff concluded that it has reasonable assurance that waste disposal at the SDF meets the 10 CFR 61 performance objectives for protection of individuals against intrusion (chap.61.42), protection of individuals during operations (chap.61.43), and site stability (chap.61.44). However, based on its evaluation of DOE's results and independent sensitivity analyses conducted with DOE's models, the NRC staffmore » concluded that it did not have reasonable assurance that DOE's disposal activities at the SDF meet the performance objective for protection of the general population from releases of radioactivity (chap.61.41) evaluated at a dose limit of 0.25 mSv/yr (25 mrem/yr) total effective dose equivalent (TEDE). NRC staff also concluded that the potential dose to a member of the public is expected to be limited (i.e., is expected to be similar to or less than the public dose limit in chap.20.1301 of 1 mSv/yr [100 mrem/yr] TEDE) and is expected to occur many years after site closure. The NRC staff used risk insights gained from review of the SDF PA, its experience monitoring DOE disposal actions at the SDF over the last 5 years, as well as independent analysis and modeling to identify factors that are important to assessing whether DOE's disposal actions meet the performance objectives. Many of these factors are similar to factors identified in the NRC staff's 2005 review of salt waste disposal at the SDF. Key areas of interest continue to be waste form and disposal unit degradation, the effectiveness of infiltration and erosion controls, and estimation of the radiological inventory. Based on these factors, NRC is revising its plan for monitoring salt waste disposal at the SDF in coordination with South Carolina Department of Health and Environmental Control (SCDHEC). DOE has completed or begun additional work related to salt waste disposal to address these factors. NRC staff continues to evaluate information related to the performance of the SDF and has been working with DOE and SCDHEC to resolve NRC staff's technical concerns. (authors)« less

Development of Risk Insights for Regulatory Review of a Near-Surface Disposal Facility for Radioactive Waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Esh, D.W.; Ridge, A.C.; Thaggard, M.

2006-07-01

Section 3116 of the Ronald W. Reagan National Defense Authorization Act for Fiscal Year 2005 (NDAA) requires the Department of Energy (DOE) to consult with the Nuclear Regulatory Commission (NRC) about non-High Level Waste (HLW) determinations. In its consultative role, NRC performs technical reviews of DOE's waste determinations but does not have regulatory authority over DOE's waste disposal activities. The safety of disposal is evaluated by comparing predicted disposal facility performance to the performance objectives specified in NRC regulations for the disposal of low-level waste (10 CFR Part 61 Subpart C). The performance objectives contain criteria for protection of themore » public, protection of inadvertent intruders, protection of workers, and stability of the disposal site after closure. The potential radiological dose to receptors typically is evaluated with a performance assessment (PA) model that simulates the release of radionuclides from the disposal site, transport of radionuclides through the environment, and exposure of potential receptors to residual contamination for thousands of years. This paper describes NRC's development and use of independent performance assessment modeling to facilitate review of DOE's non-HLW determination for the Saltstone Disposal Facility (SDF) at the Savannah River Site. NRC's review of the safety of near-surface disposal of radioactive waste at the SDF was facilitated and focused by risk insights developed with an independent PA model. The main components of NRC's performance assessment model are presented. The development of risk insights that allow the staff to focus review efforts on those areas that are most important to satisfying the performance objectives is discussed. Uncertainty analysis was performed of the full stochastic model using genetic variable selection algorithms. The results of the uncertainty analysis were then used to guide the development of simulations of other scenarios to understand the key risk drivers and risk limiters of the SDF. Review emphasis was placed on those aspects of the disposal system that were expected to drive performance: the physical and chemical performance of the cementitious wasteform and concrete vaults. Refinement of the modeling of the degradation and release from the cementitious wasteform had a significant effect on the predicted dose to a member of the public. (authors)« less

Supplemental Immobilization of Hanford Low-Activity Waste: Cast Stone Screening Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Westsik, Joseph H.; Piepel, Gregory F.; Lindberg, Michael J.

2013-09-30

More than 56 million gallons of radioactive and hazardous waste are stored in 177 underground storage tanks at the U.S. Department of Energy’s (DOE’s) Hanford Site in southeastern Washington State. The Hanford Tank Waste Treatment and Immobilization Plant (WTP) is being constructed to treat the wastes and immobilize them in a glass waste form. The WTP includes a pretreatment facility to separate the wastes into a small volume of high-level waste (HLW) containing most of the radioactivity and a larger volume of low-activity waste (LAW) containing most of the nonradioactive chemicals. The HLW will be converted to glass in themore » HLW vitrification facility for ultimate disposal at an offsite federal repository. At least a portion (~35%) of the LAW will be converted to glass in the LAW vitrification facility and will be disposed of onsite at the Integrated Disposal Facility (IDF). The pretreatment and HLW vitrification facilities will have the capacity to treat and immobilize the wastes destined for each facility. However, a second LAW immobilization facility will be needed for the expected volume of LAW requiring immobilization. A cementitious waste form known as Cast Stone is being considered to provide the required additional LAW immobilization capacity. The Cast Stone waste form must be acceptable for disposal in the IDF. The Cast Stone waste form and immobilization process must be tested to demonstrate that the final Cast Stone waste form can comply with the waste acceptance criteria for the disposal facility and that the immobilization processes can be controlled to consistently provide an acceptable waste form product. Further, the waste form must be tested to provide the technical basis for understanding the long-term performance of the waste form in the disposal environment. These waste form performance data are needed to support risk assessment and performance assessment (PA) analyses of the long-term environmental impact of the waste disposal in the IDF. The PA is needed to satisfy both Washington State IDF Permit and DOE Order requirements. Cast Stone has been selected for solidification of radioactive wastes including WTP aqueous secondary wastes treated at the Effluent Treatment Facility (ETF) at Hanford. A similar waste form called Saltstone is used at the Savannah River Site (SRS) to solidify its LAW tank wastes.« less

WTP Waste Feed Qualification: Glass Fabrication Unit Operation Testing Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M. E.; Newell, J. D.; Johnson, F. C.

The waste feed qualification program is being developed to protect the Hanford Tank Waste Treatment and Immobilization Plant (WTP) design, safety basis, and technical basis by assuring waste acceptance requirements are met for each staged waste feed campaign prior to transfer from the Tank Operations Contractor to the feed receipt vessels inside the Pretreatment Facility. The Waste Feed Qualification Program Plan describes the three components of waste feed qualification: 1. Demonstrate compliance with the waste acceptance criteria 2. Determine waste processability 3. Test unit operations at laboratory scale. The glass fabrication unit operation is the final step in the processmore » demonstration portion of the waste feed qualification process. This unit operation generally consists of combining each of the waste feed streams (high-level waste (HLW) and low-activity waste (LAW)) with Glass Forming Chemicals (GFCs), fabricating glass coupons, performing chemical composition analysis before and after glass fabrication, measuring hydrogen generation rate either before or after glass former addition, measuring rheological properties before and after glass former addition, and visual observation of the resulting glass coupons. Critical aspects of this unit operation are mixing and sampling of the waste and melter feeds to ensure representative samples are obtained as well as ensuring the fabrication process for the glass coupon is adequate. Testing was performed using a range of simulants (LAW and HLW simulants), and these simulants were mixed with high and low bounding amounts of GFCs to evaluate the mixing, sampling, and glass preparation steps in shielded cells using laboratory techniques. The tests were performed with off-the-shelf equipment at the Savannah River National Laboratory (SRNL) that is similar to equipment used in the SRNL work during qualification of waste feed for the Defense Waste Processing Facility (DWPF) and other waste treatment facilities at the Savannah River Site. It is not expected that the exact equipment used during this testing will be used during the waste feed qualification testing for WTP, but functionally similar equipment will be used such that the techniques demonstrated would be applicable. For example, the mixing apparatus could use any suitable mixer capable of being remoted and achieving similar mixing speeds to those tested.« less

Waste Determination Equivalency - 12172

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freeman, Rebecca D.

2012-07-01

The Savannah River Site (SRS) is a Department of Energy (DOE) facility encompassing approximately 800 square kilometers near Aiken, South Carolina which began operations in the 1950's with the mission to produce nuclear materials. The SRS contains fifty-one tanks (2 stabilized, 49 yet to be closed) distributed between two liquid radioactive waste storage facilities at SRS containing carbon steel underground tanks with storage capacities ranging from 2,800,000 to 4,900,000 liters. Treatment of the liquid waste from these tanks is essential both to closing older tanks and to maintaining space needed to treat the waste that is eventually vitrified or disposedmore » of onsite. Section 3116 of the Ronald W. Reagan National Defense Authorization Act of Fiscal Year 2005 (NDAA) provides the Secretary of Energy, in consultation with the Nuclear Regulatory Commission (NRC), a methodology to determine that certain waste resulting from prior reprocessing of spent nuclear fuel are not high-level radioactive waste if it can be demonstrated that the waste meets the criteria set forth in Section 3116(a) of the NDAA. The Secretary of Energy, in consultation with the NRC, signed a determination in January 2006, pursuant to Section 3116(a) of the NDAA, for salt waste disposal at the SRS Saltstone Disposal Facility. This determination is based, in part, on the Basis for Section 3116 Determination for Salt Waste Disposal at the Savannah River Site and supporting references, a document that describes the planned methods of liquid waste treatment and the resulting waste streams. The document provides descriptions of the proposed methods for processing salt waste, dividing them into 'Interim Salt Processing' and later processing through the Salt Waste Processing Facility (SWPF). Interim Salt Processing is separated into Deliquification, Dissolution, and Adjustment (DDA) and Actinide Removal Process/Caustic Side Solvent Extraction Unit (ARP/MCU). The Waste Determination was signed by the Secretary of Energy in January of 2006 based on proposed processing techniques with the expectation that it could be revised as new processing capabilities became viable. Once signed, however, it became evident that any changes would require lengthy review and another determination signed by the Secretary of Energy. With the maturation of additional salt removal technologies and the extension of the SWPF start-up date, it becomes necessary to define 'equivalency' to the processes laid out in the original determination. For the purposes of SRS, any waste not processed through Interim Salt Processing must be processed through SWPF or an equivalent process, and therefore a clear statement of the requirements for a process to be equivalent to SWPF becomes necessary. (authors)« less

Liquid secondary waste: Waste form formulation and qualification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cozzi, A. D.; Dixon, K. L.; Hill, K. A.

The Hanford Site Effluent Treatment Facility (ETF) currently treats aqueous waste streams generated during site cleanup activities. When the Hanford Tank Waste Treatment and Immobilization Plant (WTP) begins operations, including Direct Feed Low Activity Waste (DFLAW) vitrification, a liquid secondary waste (LSW) stream from the WTP will need to be treated. The volume of effluent for treatment at the ETF will increase significantly. The powdered salt waste form produced by the ETF will be replaced by a stabilized solidified waste form for disposal in Hanford’s Integrated Disposal Facility (IDF). Washington River Protection Solutions is implementing a Secondary Liquid Waste Immobilizationmore » Technology Development Plan to address the technology needs for a waste form and solidification process to treat the increased volume of waste planned for disposal at the IDF. Waste form testing to support this plan is composed of work in the near term to provide data as input to a performance assessment (PA) for Hanford’s IDF. In 2015, three Hanford Liquid Secondary Waste simulants were developed based on existing and projected waste streams. Using these waste simulants, fourteen mixes of Hanford Liquid Secondary Waste were prepared and tested varying the waste simulant, the water-to-dry materials ratio, and the dry materials blend composition.1 In FY16, testing was performed using a simulant of the EMF process condensate blended with the caustic scrubber—from the Low Activity Waste (LAW) melter—, processed through the ETF. The initial EMF-16 simulant will be based on modeling efforts performed to determine the mass balance of the ETF for the DFLAW.2 The compressive strength of all of the mixes exceeded the target of 3.4 MPa (500 psi) to meet the requirements identified as potential IDF Waste Acceptance Criteria in Table 1 of the Secondary Liquid Waste Immobilization Technology Development Plan.3 The hydraulic properties of the waste forms tested (hydraulic conductivity and water characteristic curves) were comparable to the properties measured on the Savannah River Site (SRS) Saltstone waste form. Future testing should include efforts to first; 1) determine the rate and amount of ammonia released during each unit operation of the treatment process to determine if additional ammonia management is required, then; 2) reduce the ammonia content of the ETF concentrated brine prior to solidification, making the waste more amenable to grouting, or 3) manage the release of ammonia during production and ongoing release during storage of the waste form, or 4) develop a lower pH process/waste form thereby precluding ammonia release.« less

DEMONSTRATION OF LEACHXS/ORCHESTRA CAPABILITIES BY SIMULATING CONSTITUENT RELEASE FROM A CEMENTITIOUS WASTE FORM IN A REINFORCED CONCRETE VAULT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langton, C.; Meeussen, J.; Sloot, H.

2010-03-31

The objective of the work described in this report is to demonstrate the capabilities of the current version of LeachXS{trademark}/ORCHESTRA for simulating chemical behavior and constituent release processes in a range of applications that are relevant to the CBP. This report illustrates the use of LeachXS{trademark}/ORCHESTRA for the following applications: (1) Comparing model and experimental results for leaching tests for a range of cementitious materials including cement mortars, grout, stabilized waste, and concrete. The leaching test data includes liquid-solid partitioning as a function of pH and release rates based on laboratory column, monolith, and field testing. (2) Modeling chemical speciationmore » of constituents in cementitious materials, including liquid-solid partitioning and release rates. (3) Evaluating uncertainty in model predictions based on uncertainty in underlying composition, thermodynamic, and transport characteristics. (4) Generating predominance diagrams to evaluate predicted chemical changes as a result of material aging using the example of exposure to atmospheric conditions. (5) Modeling coupled geochemical speciation and diffusion in a three layer system consisting of a layer of Saltstone, a concrete barrier, and a layer of soil in contact with air. The simulations show developing concentration fronts over a time period of 1000 years. (6) Modeling sulfate attack and cracking due to ettringite formation. A detailed example for this case is provided in a separate article by the authors (Sarkar et al. 2010). Finally, based on the computed results, the sensitive input parameters for this type of modeling are identified and discussed. The chemical speciation behavior of substances is calculated for a batch system and also in combination with transport and within a three layer system. This includes release from a barrier to the surrounding soil as a function of time. As input for the simulations, the physical and chemical properties of the materials are used. The test cases used in this demonstration are taken from Reference Cases for Use in the Cementitious Barriers Partnership (Langton et al. 2009). Before it is possible to model the release of substances from stabilized waste or radioactive grout through a cement barrier into the engineered soil barrier or natural soil, the relevant characteristics of such materials must be known. Additional chemical characteristics are needed for mechanistic modeling to be undertaken, not just the physical properties relevant for modeling of transport. The minimum required properties for modeling are given in Section 5.0, 'Modeling the chemical speciation of a material'.« less

BEHAVIOR OF MERCURY DURING DWPF CHEMICAL PROCESS CELL PROCESSING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zamecnik, J.; Koopman, D.

2012-04-09

The Defense Waste Processing Facility has experienced significant issues with the stripping and recovery of mercury in the Chemical Processing Cell (CPC). The stripping rate has been inconsistent, often resulting in extended processing times to remove mercury to the required endpoint concentration. The recovery of mercury in the Mercury Water Wash Tank has never been high, and has decreased significantly since the Mercury Water Wash Tank was replaced after the seventh batch of Sludge Batch 5. Since this time, essentially no recovery of mercury has been seen. Pertinent literature was reviewed, previous lab-scale data on mercury stripping and recovery wasmore » examined, and new lab-scale CPC Sludge Receipt and Adjustment Tank (SRAT) runs were conducted. For previous lab-scale data, many of the runs with sufficient mercury recovery data were examined to determine what factors affect the stripping and recovery of mercury and to improve closure of the mercury material balance. Ten new lab-scale SRAT runs (HG runs) were performed to examine the effects of acid stoichiometry, sludge solids concentration, antifoam concentration, form of mercury added to simulant, presence of a SRAT heel, operation of the SRAT condenser at higher than prototypic temperature, varying noble metals from none to very high concentrations, and higher agitation rate. Data from simulant runs from SB6, SB7a, glycolic/formic, and the HG tests showed that a significant amount of Hg metal was found on the vessel bottom at the end of tests. Material balance closure improved from 12-71% to 48-93% when this segregated Hg was considered. The amount of Hg segregated as elemental Hg on the vessel bottom was 4-77% of the amount added. The highest recovery of mercury in the offgas system generally correlated with the highest retention of Hg in the slurry. Low retention in the slurry (high segregation on the vessel bottom) resulted in low recovery in the offgas system. High agitation rates appear to result in lower retention of mercury in the slurry. Both recovery of mercury in the offgas system and removal (segregation + recovery) from the slurry correlate with slurry consistency. Higher slurry consistency results in better retention of Hg in the slurry (less segregation) and better recovery in the offgas system, but the relationships of recovery and retention with consistency are sludge dependent. Some correlation with slurry yield stress and acid stoichiometry was also found. Better retention of mercury in the slurry results in better recovery in the offgas system because the mercury in the slurry is stripped more easily than the segregated mercury at the bottom of the vessel. Although better retention gives better recovery, the time to reach a particular slurry mercury content (wt%) is longer than if the retention is poorer because the segregation is faster. The segregation of mercury is generally a faster process than stripping. The stripping factor (mass of water evaporated per mass of mercury stripped) of mercury at the start of boiling were found to be less than 1000 compared to the assumed design basis value of 750 (the theoretical factor is 250). However, within two hours, this value increased to at least 2000 lb water per lb Hg. For runs with higher mercury recovery in the offgas system, the stripping factor remained around 2000, but runs with low recovery had stripping factors of 4000 to 40,000. DWPF data shows similar trends with the stripping factor value increasing during boiling. These high values correspond to high segregation and low retention of mercury in the sludge. The stripping factor for a pure Hg metal bead in water was found to be about 10,000 lb/lb. About 10-36% of the total Hg evaporated in a SRAT cycle was refluxed back to the SRAT during formic acid addition and boiling. Mercury is dissolved as a result of nitric acid formation from absorption of NO{sub x}. The actual solubility of dissolved mercury in the acidic condensate is about 100 times higher than the actual concentrations measured. Mercury metal present in the MWWT from previous batches could be dissolved by this acidic condensate. The test of the effect of higher SRAT condenser temperature on recovery of mercury in the MWWT and offgas system was inconclusive. The recovery at higher temperature was lower than several low temperature runs, but about the same as other runs. Factors other than temperature appear to affect the mercury recovery. The presence of chloride and iodide in simulants resulted in the formation of mercurous chloride and mercurous iodide, respectively, in the offgas system. Actual waste data shows that the chloride content is much less than the simulant concentrations. Future simulant tests should minimize the addition of chloride. Similarly, iodine addition should be eliminated unless actual waste analyses show it to be present; currently, total iodine is not measured on actual waste samples.« less

System analyses on advanced nuclear fuel cycle and waste management

NASA Astrophysics Data System (ADS)

Cheon, Myeongguk

To evaluate the impacts of accelerator-driven transmutation of waste (ATW) fuel cycle on a geological repository, two mathematical models are developed: a reactor system analysis model and a high-level waste (HLW) conditioning model. With the former, fission products and residual trans-uranium (TRU) contained in HLW generated from a reference ATW plant operations are quantified and the reduction of TRU inventory included in commercial spent-nuclear fuel (CSNF) is evaluated. With the latter, an optimized waste loading and composition in solidification of HLW are determined and the volume reduction of waste packages associated with CSNF is evaluated. WACOM, a reactor system analysis code developed in this study for burnup calculation, is validated by ORIGEN2.1 and MCNP. WACOM is used to perform multicycle analysis for the reference lead-bismuth eutectic (LBE) cooled transmuter. By applying the results of this analysis to the reference ATW deployment scenario considered in the ATW roadmap, the HLW generated from the ATW fuel cycle is quantified and the reduction of TRU inventory contained in CSNF is evaluated. A linear programming (LP) model has been developed for determination of an optimized waste loading and composition in solidification of HLW. The model has been applied to a US-defense HLW. The optimum waste loading evaluated by the LP model was compared with that estimated by the Defense Waste Processing Facility (DWPF) in the US and a good agreement was observed. The LP model was then applied to the volume reduction of waste packages associated with CSNF. Based on the obtained reduction factors, the expansion of Yucca Mountain Repository (YMR) capacity is evaluated. It is found that with the reference ATW system, the TRU contained in CSNF could be reduced by a factor of ˜170 in terms of inventory and by a factor of ˜40 in terms of toxicity under the assumed scenario. The number of waste packages related to CSNF could be reduced by a factor of ˜8 in terms of volume and by factor of ˜10 on the basis of electricity generation when a sufficient cooling time for discharged spent fuel and zero process chemicals in HLW are assumed. The expansion factor of Yucca Mountain Repository capacity is estimated to be a factor of 2.4, much smaller than the reduction factor of CSNF waste packages, due to the existence of DOE-owned spent fuel and HLW. The YMR, however, could support 10 times greater electricity generation as long as the statutory capacity of DOE-owned SNF and HLW remains unchanged. This study also showed that the reduction of the number of waste packages could strongly be subject to the heat generation rate of HLW and the amount of process chemicals contained in HLW. For a greater reduction of the number of waste packages, a sufficient cooling time for discharged fuel and efforts to minimize the amount of process chemicals contained in HLW are crucial.

The Cementitious Barriers Partnership Experimental Programs and Software Advancing DOE’s Waste Disposal/Tank Closure Efforts – 15436

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burns, Heather; Flach, Greg; Smith, Frank

2015-01-27

The U.S. Department of Energy Environmental Management (DOE-EM) Office of Tank Waste Management-sponsored Cementitious Barriers Partnership (CBP) is chartered with providing the technical basis for implementing cement-based waste forms and radioactive waste containment structures for long-term disposal. DOE needs in this area include the following to support progress in final treatment and disposal of legacy waste and closure of High-Level Waste (HLW) tanks in the DOE complex: long-term performance predictions, flow sheet development and flow sheet enhancements, and conceptual designs for new disposal facilities. The DOE-EM Cementitious Barriers Partnership is producing software and experimental programs resulting in new methods andmore » data needed for end-users involved with environmental cleanup and waste disposal. Both the modeling tools and the experimental data have already benefited the DOE sites in the areas of performance assessments by increasing confidence backed up with modeling support, leaching methods, and transport properties developed for actual DOE materials. In 2014, the CBP Partnership released the CBP Software Toolbox –“Version 2.0” which provides concrete degradation models for 1) sulfate attack, 2) carbonation, and 3) chloride initiated rebar corrosion, and includes constituent leaching. These models are applicable and can be used by both DOE and the Nuclear Regulatory Commission (NRC) for service life and long-term performance evaluations and predictions of nuclear and radioactive waste containment structures across the DOE complex, including future SRS Saltstone and HLW tank performance assessments and special analyses, Hanford site HLW tank closure projects and other projects in which cementitious barriers are required, the Advanced Simulation Capability for Environmental Management (ASCEM) project which requires source terms from cementitious containment structures as input to their flow simulations, regulatory reviews of DOE performance assessments, and Nuclear Regulatory Commission reviews of commercial nuclear power plant (NPP) structures which are part of the overall US Energy Security program to extend the service life of NPPs. In addition, the CBP experimental programs have had a significant impact on the DOE complex by providing specific data unique to DOE sodium salt wastes at Hanford and SRS which are not readily available in the literature. Two recent experimental programs on cementitious phase characterization and on technetium (Tc) mobility have provided significant conclusions as follows: recent mineralogy characterization discussed in this paper illustrates that sodium salt waste form matrices are somewhat similar to but not the same as those found in blended cement matrices which to date have been used in long-term thermodynamic modeling and contaminant sequestration as a first approximation. Utilizing the CBP generated data in long-term performance predictions provides for a more defensible technical basis in performance evaluations. In addition, recent experimental studies related to technetium mobility indicate that conventional leaching protocols may not be conservative for direct disposal of Tc-containing waste forms in vadose zone environments. These results have the potential to influence the current Hanford supplemental waste treatment flow sheet and disposal conceptual design.« less

Dissolution of Simulated and Radioactive Savannah River Site High-Level Waste Sludges with Oxalic Acid & Citric Acid Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

STALLINGS, MARY

This report presents findings from tests investigating the dissolution of simulated and radioactive Savannah River Site sludges with 4 per cent oxalic acid and mixtures of oxalic and citric acid previously recommended by a Russian team from the Khlopin Radium Institute and the Mining and Chemical Combine (MCC). Testing also included characterization of the simulated and radioactive waste sludges. Testing results showed the following: Dissolution of simulated HM and PUREX sludges with oxalic and citric acid mixtures at SRTC confirmed general trends reported previously by Russian testing. Unlike the previous Russian testing six sequential contacts of a mixture of oxalicmore » acid citric acids at a 2:1 ratio (v/w) of acid to sludge did not produce complete dissolution of simulated HM and PUREX sludges. We observed that increased sludge dissolution occurred at a higher acid to sludge ratio, 50:1 (v/w), compared to the recommended ratio of 2:1 (v/w). We observed much lower dissolution of aluminum in a simulated HM sludge by sodium hydroxide leaching. We attribute the low aluminum dissolution in caustic to the high fraction of boehmite present in the simulated sludge. Dissolution of HLW sludges with 4 per cent oxalic acid and oxalic/citric acid followed general trends observed with simulated sludges. The limited testing suggests that a mixture of oxalic and citric acids is more efficient for dissolving HM and PUREX sludges and provides a more homogeneous dissolution of HM sludge than oxalic acid alone. Dissolution of HLW sludges in oxalic and oxalic/citric acid mixtures produced residual sludge solids that measured at higher neutron poison to equivalent 235U weight ratios than that in the untreated sludge solids. This finding suggests that residual solids do not present an increased nuclear criticality safety risk. Generally the neutron poison to equivalent 235U weight ratios of the acid solutions containing dissolved sludge components are lower than those in the untreated sludge solids. We recommend that these results be evaluated further to determine if these solutions contain sufficient neutron poisons. We observed low general corrosion rates in tests in which carbon steel coupons were contacted with solutions of oxalic acid, citric acid and mixtures of oxalic and citric acids. Wall thinning can be minimized by maintaining short contact times with these acid solutions. We recommend additional testing with oxalic and oxalic/citric acid mixtures to measure dissolution performance of sludges that have not been previously dried. This testing should include tests to clearly ascertain the effects of total acid strength and metal complexation on dissolution performance. Further work should also evaluate the downstream impacts of citric acid on the SRS High-Level Waste System (e.g., radiochemical separations in the Salt Waste Processing Facility and addition of organic carbon in the Saltstone and Defense Waste Processing facilities).« less

Using polymerization, glass structure, and quasicrystalline theory to produce high level radioactive borosilicate glass remotely: a 20+ year legacy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, Carol M.

Vitrification is currently the most widely used technology for the treatment of high level radioactive wastes (HLW) throughout the world. Most of the nations that have generated HLW are immobilizing in borosilicate glass. One of the primary reasons that glass has become the most widely used immobilization media is the relative simplicity of the vitrification process, e.g. melt a highly variable waste with some glass forming additives such as SiO 2 and B 2O 3 in the form of a premelted frit and pour the molten mixture into a stainless steel canister. Seal the canister before moisture can enter themore » canister (10’ tall by 2’ in diameter) so the canister does not corrode from the inside out. Glass has also become widely used for HLW is that due to the fact that the short range order (SRO) and medium range order (MRO) found in the structure of glass atomistically bonds the radionuclides and hazardous species in the waste. The SRO and MRO have also been found to govern the melt properties such as viscosity and resistivity of the melt and the crystallization potential and solubility of certain species. Furthermore, the molecular structure of the glass also controls the glass durability, i.e. the contaminant/radionuclide release, by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. The molecular structure is flexible and hence accounts for the flexibility of glass formulations to HLW waste variability. Nuclear waste glasses melt between 1050-1150°C which minimizes the volatility of radioactive components such as 99Tc, 137Cs, and 129I. Nuclear waste glasses have good long term stability including irradiation resistance. Process control models were developed based on the molecular structure of glass, polymerization theory of glass, and quasicrystalline theory of glass crystallization. These models create a glass which is durable, pourable, and processable with 95% accuracy without knowing from batch to batch what the composition of the waste coming out of the storage tanks will be. These models have operated the Savannah River Site Defense Waste Processing Facility (SRS DWPF), which is the world’s largest HLW Joule heated ceramic melter, since 1996. This unique “feed forward” process control, which qualifies the durability, pourability, and processability of the waste plus glass additive mixture before it enters the melter, has enabled ~8000 tons of HLW glass and 4242 canisters to be produced since 1996 with only one melter replacement.« less

Tank 40 Final Sludge Batch 8 Chemical Characterization Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, Christopher J.

2013-09-19

A sample of Sludge Batch 8 (SB8) was pulled from Tank 40 in order to obtain radionuclide inventory analyses necessary for compliance with the Waste Acceptance Product Specifications (WAPS). The SB8 WAPS sample was also analyzed for chemical composition, including noble metals, and fissile constituents, and these results are reported here. These analyses along with the WAPS radionuclide analyses will help define the composition of the sludge in Tank 40 that is currently being fed to the Defense Waste Processing Facility (DWPF) as SB8. At SRNL, the 3-L Tank 40 SB8 sample was transferred from the shipping container into amore » 4-L high density polyethylene bottle and solids were allowed to settle. Supernate was then siphoned off and circulated through the shipping container to complete the transfer of the sample. Following thorough mixing of the 3-L sample, a 553 g sub-sample was removed. This sub-sample was then utilized for all subsequent slurry sample preparations. Eight separate aliquots of the slurry were digested, four with HNO{sub 3}/HCl (aqua regia) in sealed Teflon(r) vessels and four with NaOH/Na{sub 2}O{sub 2} (alkali or peroxide fusion) using Zr crucibles. Two Analytical Reference Glass - 1 (ARG-1) standards were digested along with a blank for each preparation. Each aqua regia digestion and blank was diluted to 1:100 mL with deionized water and submitted to Analytical Development (AD) for inductively coupled plasma - atomic emission spectroscopy (ICP-AES) analysis, inductively coupled plasma - mass spectrometry (ICP-MS) analysis, atomic absorption spectroscopy (AA) for As and Se, and cold vapor atomic absorption spectroscopy (CV-AA) for Hg. Equivalent dilutions of the alkali fusion digestions and blank were submitted to AD for ICP-AES analysis. Tank 40 SB8 supernate was collected from a mixed slurry sample in the SRNL Shielded Cells and submitted to AD for ICP-AES, ion chromatography (IC), total base/free OH-/other base, total inorganic carbon/total organic carbon (TIC/TOC) analyses. Weighted dilutions of slurry were submitted for IC, TIC/TOC, and total base/free OH-/other base analyses. Activities for U-233, U-235, and Pu-239 were determined from the ICP-MS data for the aqua regia digestions of the Tank 40 WAPS slurry using the specific activity of each isotope. The Pu-241 value was determined from a Pu-238/-241 method developed by SRNL AD and previously described.« less

Tank 40 final sludge batch 9 chemical and fissile radionuclide characterization results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.; Kubilius, W. P.; Pareizs, J. M.

A sample of Sludge Batch (SB) 9 was pulled from Tank 40 in order to obtain radionuclide inventory analyses necessary for compliance with the Waste Acceptance Product Specifications (WAPS)i. The SB9 WAPS sample was also analyzed for chemical composition, including noble metals, and fissile constituents, and these results are reported here. These analyses along with the WAPS radionuclide analyses will help define the composition of the sludge in Tank 40 that is fed to the Defense Waste Processing Facility (DWPF) as SB9. At the Savannah River National Laboratory (SRNL), the 3-L Tank 40 SB9 sample was transferred from the shippingmore » container into a 4-L high density polyethylene bottle and solids were allowed to settle. Supernate was then siphoned off and circulated through the shipping container to complete the transfer of the sample. Following thorough mixing of the 3-L sample, a 547 g sub-sample was removed. This sub-sample was then utilized for all subsequent slurry sample preparations. Eight separate aliquots of the slurry were digested, four with HNO3/HCl (aqua regiaii) in sealed Teflon® vessels and four with NaOH/Na2O2 (alkali or peroxide fusioniii) using Zr crucibles. Three Analytical Reference Glass – 1iv (ARG-1) standards were digested along with a blank for each preparation. Each aqua regia digestion and blank was diluted to 1:100 with deionized water and submitted to Analytical Development (AD) for inductively coupled plasma – atomic emission spectroscopy (ICP-AES) analysis, inductively coupled plasma – mass spectrometry (ICP-MS) analysis, atomic absorption spectroscopy (AA) for As and Se, and cold vapor atomic absorption spectroscopy (CV-AA) for Hg. Equivalent dilutions of the alkali fusion digestions and blank were submitted to AD for ICP-AES analysis. Tank 40 SB9 supernate was collected from a mixed slurry sample in the SRNL Shielded Cells and submitted to AD for ICP-AES, ion chromatography (IC), total base/free OH-/other base, total inorganic carbon/total organic carbon (TIC/TOC) analyses. Weighted dilutions of slurry were submitted for IC, TIC/TOC, and total base/free OH-/other base analyses. Activities for U-233, U-235, and Pu-239 were determined from the ICP-MS data for the aqua regia digestions of the SB9 WAPS slurry using the specific activity of each isotope. The Pu-241 value was determined from a Pu-238/-241 method developed by SRNL AD and previously described.v« less

Using polymerization, glass structure, and quasicrystalline theory to produce high level radioactive borosilicate glass remotely: a 20+ year legacy

DOE PAGES

Jantzen, Carol M.

2017-03-27

Vitrification is currently the most widely used technology for the treatment of high level radioactive wastes (HLW) throughout the world. Most of the nations that have generated HLW are immobilizing in borosilicate glass. One of the primary reasons that glass has become the most widely used immobilization media is the relative simplicity of the vitrification process, e.g. melt a highly variable waste with some glass forming additives such as SiO 2 and B 2O 3 in the form of a premelted frit and pour the molten mixture into a stainless steel canister. Seal the canister before moisture can enter themore » canister (10’ tall by 2’ in diameter) so the canister does not corrode from the inside out. Glass has also become widely used for HLW is that due to the fact that the short range order (SRO) and medium range order (MRO) found in the structure of glass atomistically bonds the radionuclides and hazardous species in the waste. The SRO and MRO have also been found to govern the melt properties such as viscosity and resistivity of the melt and the crystallization potential and solubility of certain species. Furthermore, the molecular structure of the glass also controls the glass durability, i.e. the contaminant/radionuclide release, by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. The molecular structure is flexible and hence accounts for the flexibility of glass formulations to HLW waste variability. Nuclear waste glasses melt between 1050-1150°C which minimizes the volatility of radioactive components such as 99Tc, 137Cs, and 129I. Nuclear waste glasses have good long term stability including irradiation resistance. Process control models were developed based on the molecular structure of glass, polymerization theory of glass, and quasicrystalline theory of glass crystallization. These models create a glass which is durable, pourable, and processable with 95% accuracy without knowing from batch to batch what the composition of the waste coming out of the storage tanks will be. These models have operated the Savannah River Site Defense Waste Processing Facility (SRS DWPF), which is the world’s largest HLW Joule heated ceramic melter, since 1996. This unique “feed forward” process control, which qualifies the durability, pourability, and processability of the waste plus glass additive mixture before it enters the melter, has enabled ~8000 tons of HLW glass and 4242 canisters to be produced since 1996 with only one melter replacement.« less

RESULTS OF THE FY09 ENHANCED DOE HIGH LEVEL WASTE MELTER THROUGHPUT STUDIES AT SRNL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, F.; Edwards, T.

2010-06-23

High-level waste (HLW) throughput (i.e., the amount of waste processed per unit time) is a function of two critical parameters: waste loading (WL) and melt rate. For the Waste Treatment and Immobilization Plant (WTP) at the Hanford Site and the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS), increasing HLW throughput would significantly reduce the overall mission life cycle costs for the Department of Energy (DOE). The objective of this task is to develop data, assess property models, and refine or develop the necessary models to support increased WL of HLW at SRS. It is a continuationmore » of the studies initiated in FY07, but is under the specific guidance of a Task Change Request (TCR)/Work Authorization received from DOE headquarters (Project Number RV071301). Using the data generated in FY07, FY08 and historical data, two test matrices (60 glasses total) were developed at the Savannah River National Laboratory (SRNL) in order to generate data in broader compositional regions. These glasses were fabricated and characterized using chemical composition analysis, X-ray Diffraction (XRD), viscosity, liquidus temperature (TL) measurement and durability as defined by the Product Consistency Test (PCT). The results of this study are summarized below: (1) In general, the current durability model predicts the durabilities of higher waste loading glasses quite well. A few of the glasses exhibited poorer durability than predicted. (2) Some of the glasses exhibited anomalous behavior with respect to durability (normalized leachate for boron (NL [B])). The quenched samples of FY09EM21-02, -07 and -21 contained no nepheline or other wasteform affecting crystals, but have unacceptable NL [B] values (> 10 g/L). The ccc sample of FY09EM21-07 has a NL [B] value that is more than one half the value of the quenched sample. These glasses also have lower concentrations of Al{sub 2}O{sub 3} and SiO{sub 2}. (3) Five of the ccc samples (EM-13, -14, -15, -29 and -30) completely crystallized with both magnetite and nepheline, and still had extremely low NL [B] values. These particular glasses have more CaO present than any of the other glasses in the matrix. It appears that while all of the glasses contain nepheline, the NL [B] values decrease as the CaO concentration increases from 2.3 wt% to 4.3 wt%. A different form of nepheline may be created at higher concentrations of CaO that does not significantly reduce glass durability. (4) The T{sub L} model appears to be under-predicting the measured values of higher waste loading glasses. Trends in T{sub L} with composition are not evident in the data from these studies. (5) A small number of glasses in the FY09 matrix have measured viscosities that are much lower than the viscosity range over which the current model was developed. The decrease in viscosity is due to a higher concentration of non-bridging oxygens (NBO). A high iron concentration is the cause of the increase in NBO. Durability, viscosity and T{sub L} data collected during FY07 and FY09 that specifically targeted higher waste loading glasses was compiled and assessed. It appears that additional data may be required to expand the coverage of the T{sub L} and viscosity models for higher waste loading glasses. In general, the compositional regions of the higher waste loading glasses are very different than those used to develop these models. On the other hand, the current durability model seems to be applicable to the new data. At this time, there is no evidence to modify this model; however additional experimental studies should be conducted to determine the cause of the anomalous durability data.« less

On the structure and radiation chemistry of iron phosphate glasses: New insights from electron spin resonance, Mössbauer, and evolved-gas mass spectroscopy

NASA Astrophysics Data System (ADS)

Griscom, D. L.; Merzbacher, C. I.; Bibler, N. E.; Imagawa, H.; Uchiyama, S.; Namiki, A.; Marasinghe, G. K.; Mesko, M.; Karabulut, M.

1998-05-01

Several vitreous forms for immobilization of plutonium and/or high-level nuclear wastes have been surveyed by electron spin resonance (ESR) to gain insights into their atomic-scale structures and to look for signs of radiolytic decomposition resulting from exposures to γ-ray doses of 30 MGy. While preliminary results are reported for Defense Waste Processing Facility (DWPF) borosilicate compositions and an experimental lanthanum-silicate glass, this paper focusses primarily on a class of glasses containing 40-75 mol% P 2O 5 and up to 40 mol% Fe 2O 3. Each of the six diverse compositions investigated displayed characteristic ESR signals (not resembling those of the iron-containing phosphorus-free glasses) comprising combinations of an extremely broad "X resonance" and a narrow "Z resonance", both centered near g=2.00 and both displaying nearly perfect Lorentzian line shapes (peak-to-peak derivative widths ˜300-600 mT and ˜30 mT, respectively, at 300 K). The X-resonance intensities in the air-melted glasses correlated linearly with Fe:P ratio up to [Fe 2O 3]/[P 2O 5] ≈ 0.6, where intensity values ˜1 spin/phosphorus were reached. Mössbauer studies showed that the [Fe 3+]/[Fe] tot ratio could be varied from 0.82 to 0.49 by raising the melting temperature in air from 1150°C to 1450°C and/or by employing mildly reducing atmospheres. The combined X + Z-resonance intensities were reduced to zero for [Fe 3+]/[Fe] tot less than ˜0.6, leaving only a much weaker spectrum attributable to Fe 3+ ions. The X and Z ESR signals of the iron phosphate glasses resemble nothing else in the literature except the correspondingly denoted signals in an iron-free amorphous peroxyborate (APB) preparation. The X and Z resonances in the latter are deemed to arise from superoxide ions (O 2-) in the borate network and in a separated Na 2O 2 phase, respectively. An asymmetric Z resonance signal attributable to interstitial O 2- species was a radiation-induced manifestation in phosphate glass of composition 50P 2O 5-20Fe 2O 3-23Li 2O-7CeO 2. Irradiated and unirradiated samples of this same glass were studied by ESR isochronal annealing and differential thermal analysis, revealing a one-for-one conversion of X to Z upon partial crystallization near 670°C and a Z → X reconversion upon partial remelting near 970°C. Heating to 1070°C in dry Ar resulted in a weight loss of ˜5 wt%, while quadrupole mass spectrometry (QMS) during ramped heating to 1550°C at a pressure of 10 -5 Pa revealed the evolution of O 2 molecules with (radiation sensitive) ion-current peaks near 1170°C and 1350-1400°C. To account for the totality of these and other results, it is suggested that air-melted iron phosphate glasses may contain macroscopic numbers of superoxide ions as an intrinsic chemical feature of their as-quenched structures. A specific four-connected phosphorus-oxygen glass network incorporating O 2- ions is proposed.

NRC Perspectives on Waste Incidental to Reprocessing Consultations and Monitoring - 13398

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKenney, Christepher A.; Suber, Gregory F.; Felsher, Harry D.

2013-07-01

Section 3116 of the Ronald W. Reagan National Defense Authorization Act for Fiscal Year 2005 (NDAA) requires the U.S. Department of Energy (DOE) to consult with the U.S. Nuclear Regulatory Commission (NRC) for certain non-high level waste (HLW) determinations. The NDAA also requires NRC to monitor DOE's disposal actions related to those determinations to assess compliance with NRC regulations in 10 CFR Part 61, Subpart C. The NDAA applies to DOE activities that will remain within the States of South Carolina and Idaho. DOE has chosen to, under DOE Order 435.1, engage in consultation with NRC for similar activities inmore » the State of Washington and New York, however, the NRC has no monitoring responsibilities. In 2007, the NRC developed a draft Final Report for Interim Use entitled, NUREG-1854: NRC Staff Guidance for Activities Related to U.S. Department of Energy Waste Determinations. Since the law was enacted, the DOE and NRC have consulted on three waste determinations within the affected States: (1) the Saltstone Disposal Facility at the Savannah River Site (SRS) within the State of South Carolina in 2005, (2) the INTEC Tank Farm at the Idaho National Laboratory within the State of Idaho in 2006, and (3) the F Tank Farm at SRS in 2011. After the end of consultation and issuance by DOE of the final waste determination, monitoring began at each of these sites, including the development of monitoring plans. In addition to the NDAA sites, DOE has requested NRC consultation support on both individual tanks and the entire C Tank Farm at the Hanford Nuclear Reservation in the State of Washington. DOE also requested consultation of waste determinations performed on the melter and related feed tanks at the West Valley site in New York that would be disposed offsite. In the next few years, NRC and DOE will consult on the last of the NDAA waste determinations for a while, the H Tank Farm waste determination at SRS. DOE may identify other activities in the future but largely NRC's role will change from doing both consultation and monitoring to being focused on monitoring activities within NDAA. DOE has identified other activities at the Hanford Nuclear Reservation that would continue consultation activities but outside of the NDAA in the future. During the past seven years of consultations and monitoring a number of lessons learned about the process, communication issues, and technical guidance have been identified. With the change in focus from reviewing initial performance assessments and draft waste determinations to long-term monitoring (e.g., individual waste tank closure, at F Tank Farm or complete tank farm closure at INTEC expected in the near future), the NRC is going to revise and update its guidance over the next few years to reflect the lessons learned and the change in focus. In addition to the lessons learned, improvements in the guidance will have to account possible rule and guidance changes underway within Part 61. This paper will discuss the initial plans, approaches, and time lines to revise the guidance within NUREG-1854, including opportunities for public involvement. (authors)« less

FY2010 ANNUAL REVIEW E-AREA LOW-LEVEL WASTE FACILITY PERFORMANCE ASSESSMENT AND COMPOSITE ANALYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butcher, T.; Swingle, R.; Crapse, K.

2011-01-01

The E-Area Low-Level Waste Facility (ELLWF) consists of a number of disposal units described in the Performance Assessment (PA)(WSRC, 2008b) and Composite Analysis (CA)(WSRC, 1997; WSRC, 1999): Low-Activity Waste (LAW) Vault, Intermediate Level (IL) Vault, Trenches (Slit Trenches [STs], Engineered Trenches [ETs], and Component-in-Grout [CIG] Trenches), and Naval Reactor Component Disposal Areas (NRCDAs). This annual review evaluates the adequacy of the approved 2008 ELLWF PA along with the Special Analyses (SAs) approved since the PA was issued. The review also verifies that the Fiscal Year (FY) 2010 low-level waste (LLW) disposal operations were conducted within the bounds of the PA/SAmore » baseline, the Savannah River Site (SRS) CA, and the Department of Energy (DOE) Disposal Authorization Statement (DAS). Important factors considered in this review include waste receipts, results from monitoring and research and development (R&D) programs, and the adequacy of controls derived from the PA/SA baseline. Sections 1.0 and 2.0 of this review are a summary of the adequacy of the PA/SA and CA, respectively. An evaluation of the FY2010 waste receipts and the resultant impact on the ELLWF is summarized in Section 3.1. The results of the monitoring program, R&D program, and other relevant factors are found in Section 3.2, 3.3 and 3.4, respectively. Section 4.0 contains the CA annual determination similarly organized. SRS low-level waste management is regulated under DOE Order 435.1 (DOE, 1999a) and is authorized under a DAS as a federal permit. The original DAS was issued by the DOE-Headquarters (DOE-HQ) on September 28, 1999 (DOE, 1999b) for the operation of the ELLWF and the Saltstone Disposal Facility (SDF). The 1999 DAS remains in effect for the regulation of the SDF. Those portions of that DAS applicable to the ELLWF were superseded by revision 1 of the DAS on July 15, 2008 (DOE, 2008b). The 2008 PA and DAS were officially implemented by the facility on October 31, 2008 and are the authorization documents for this FY2010 Annual Review. Department of Energy Headquarters approval of the 2008 DAS was subject to numerous conditions specified in the document. Two of those conditions are to update the ELLWF closure plan and monitoring plan to align with the conceptual model analyzed in the PA. Both of these conditions were met with the issuance of the PA Monitoring Plan (Millings, 2009a) and the Closure Plan (Phifer et al, 2009a). The PA Monitoring Plan was approved by DOE on July 22, 2009 and the Closure Plan was approved by DOE on May 21, 2009. Both will be updated as needed to remain consistent with the PA. The DAS also specifies that the maintenance plan include activities to resolve each of the secondary issues identified in the DOEHQ review of the 2008 PA that were not completely addressed either with supplemental material provided to the review team or in final revisions to the PA. These outstanding issues were originally documented in the 2008 update of the PA/CA Maintenance Plan (WSRC, 2008a) and in subsequent PA/CA Maintenance Plans (most recently SRNS, 2010a) as required and are actively being worked.« less

Technical Approach for Determining Key Parameters Needed for Modeling the Performance of Cast Stone for the Integrated Disposal Facility Performance Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yabusaki, Steven B.; Serne, R. Jeffrey; Rockhold, Mark L.

2015-03-30

Washington River Protection Solutions (WRPS) and its contractors at Pacific Northwest National Laboratory (PNNL) and Savannah River National Laboratory (SRNL) are conducting a development program to develop / refine the cementitious waste form for the wastes treated at the ETF and to provide the data needed to support the IDF PA. This technical approach document is intended to provide guidance to the cementitious waste form development program with respect to the waste form characterization and testing information needed to support the IDF PA. At the time of the preparation of this technical approach document, the IDF PA effort is justmore » getting started and the approach to analyze the performance of the cementitious waste form has not been determined. Therefore, this document looks at a number of different approaches for evaluating the waste form performance and describes the testing needed to provide data for each approach. Though the approach addresses a cementitious secondary aqueous waste form, it is applicable to other waste forms such as Cast Stone for supplemental immobilization of Hanford LAW. The performance of Cast Stone as a physical and chemical barrier to the release of contaminants of concern (COCs) from solidification of Hanford liquid low activity waste (LAW) and secondary wastes processed through the Effluent Treatment Facility (ETF) is of critical importance to the Hanford Integrated Disposal Facility (IDF) total system performance assessment (TSPA). The effectiveness of cementitious waste forms as a barrier to COC release is expected to evolve with time. PA modeling must therefore anticipate and address processes, properties, and conditions that alter the physical and chemical controls on COC transport in the cementitious waste forms over time. Most organizations responsible for disposal facility operation and their regulators support an iterative hierarchical safety/performance assessment approach with a general philosophy that modeling provides the critical link between the short-term understanding from laboratory and field tests, and the prediction of repository performance over repository time frames and scales. One common recommendation is that experiments be designed to permit the appropriate scaling in the models. There is a large contrast in the physical and chemical properties between the Cast Stone waste package and the IDF backfill and surrounding sediments. Cast Stone exhibits low permeability, high tortuosity, low carbonate, high pH, and low Eh whereas the backfill and native sediments have high permeability, low tortuosity, high carbonate, circumneutral pH, and high Eh. These contrasts have important implications for flow, transport, and reactions across the Cast Stone – backfill interface. Over time with transport across the interface and subsequent reactions, the sharp geochemical contrast will blur and there will be a range of spatially-distributed conditions. In general, COC mobility and transport will be sensitive to these geochemical variations, which also include physical changes in porosity and permeability from mineral reactions. Therefore, PA modeling must address processes, properties, and conditions that alter the physical and chemical controls on COC transport in the cementitious waste forms over time. Section 2 of this document reviews past Hanford PAs and SRS Saltstone PAs, which to date have mostly relied on the lumped parameter COC release conceptual models for TSPA predictions, and provides some details on the chosen values for the lumped parameters. Section 3 provides more details on the hierarchical modeling strategy and processes and mechanisms that control COC release. Section 4 summarizes and lists the key parameters for which numerical values are needed to perform PAs. Section 5 provides brief summaries of the methods used to measure the needed parameters and references to get more details.« less

RADIOACTIVE DEMONSTRATIONS OF FLUIDIZED BED STEAM REFORMING AS A SUPPLEMENTARY TREATMENT FOR HANFORD'S LOW ACTIVITY WASTE AND SECONDARY WASTES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C.; Crawford, C.; Cozzi, A.

The U.S. Department of Energy's Office of River Protection (ORP) is responsible for the retrieval, treatment, immobilization, and disposal of Hanford's tank waste. Currently there are approximately 56 million gallons of highly radioactive mixed wastes awaiting treatment. A key aspect of the River Protection Project (RPP) cleanup mission is to construct and operate the Waste Treatment and Immobilization Plant (WTP). The WTP will separate the tank waste into high-level and low-activity waste (LAW) fractions, both of which will subsequently be vitrified. The projected throughput capacity of the WTP LAW Vitrification Facility is insufficient to complete the RPP mission in themore » time frame required by the Hanford Federal Facility Agreement and Consent Order, also known as the Tri-Party Agreement (TPA), i.e. December 31, 2047. Therefore, Supplemental Treatment is required both to meet the TPA treatment requirements as well as to more cost effectively complete the tank waste treatment mission. The Supplemental Treatment chosen will immobilize that portion of the retrieved LAW that is not sent to the WTP's LAW Vitrification facility into a solidified waste form. The solidified waste will then be disposed on the Hanford site in the Integrated Disposal Facility (IDF). In addition, the WTP LAW vitrification facility off-gas condensate known as WTP Secondary Waste (WTP-SW) will be generated and enriched in volatile components such as Cs-137, I-129, Tc-99, Cl, F, and SO4 that volatilize at the vitrification temperature of 1150 C in the absence of a continuous cold cap. The current waste disposal path for the WTP-SW is to recycle it to the supplemental LAW treatment to avoid a large steady state accumulation in the pretreatment-vitrification loop. Fluidized Bed Steam Reforming (FBSR) offers a moderate temperature (700-750 C) continuous method by which LAW and/or WTP-SW wastes can be processed irrespective of whether they contain organics, nitrates, sulfates/sulfides, chlorides, fluorides, volatile radionuclides or other aqueous components. The FBSR technology can process these wastes into a crystalline ceramic (mineral) waste form. The mineral waste form that is produced by co-processing waste with kaolin clay in an FBSR process has been shown to be as durable as LAW glass. Monolithing of the granular FBSR product is being investigated to prevent dispersion during transport or burial/storage but is not necessary for performance. A Benchscale Steam Reformer (BSR) was designed and constructed at the Savannah River National Laboratory (SRNL) to treat actual radioactive wastes to confirm the findings of the non-radioactive FBSR pilot scale tests and to qualify the waste form for applications at Hanford. Radioactive testing commenced in 2010 with a demonstration of Hanford's WTP-SW where Savannah River Site (SRS) High Level Waste (HLW) secondary waste from the Defense Waste Processing Facility (DWPF) was shimmed with a mixture of I-125/129 and Tc-99 to chemically resemble WTP-SW. Ninety six grams of radioactive product were made for testing. The second campaign commenced using SRS LAW chemically trimmed to look like Hanford's LAW. Six hundred grams of radioactive product were made for extensive testing and comparison to the non-radioactive pilot scale tests. The same mineral phases were found in the radioactive and non-radioactive testing.« less

RADIOACTIVE DEMONSTRATION OF FINAL MINERALIZED WASTE FORMS FOR HANFORD WASTE TREATMENT PLANT SECONDARY WASTE BY FLUIDIZED BED STEAM REFORMING USING THE BENCH SCALE REFORMER PLATFORM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, C.; Burket, P.; Cozzi, A.

2012-02-02

The U.S. Department of Energy's Office of River Protection (ORP) is responsible for the retrieval, treatment, immobilization, and disposal of Hanford's tank waste. Currently there are approximately 56 million gallons of highly radioactive mixed wastes awaiting treatment. A key aspect of the River Protection Project (RPP) cleanup mission is to construct and operate the Waste Treatment and Immobilization Plant (WTP). The WTP will separate the tank waste into high-level and low-activity waste (LAW) fractions, both of which will subsequently be vitrified. The projected throughput capacity of the WTP LAW Vitrification Facility is insufficient to complete the RPP mission in themore » time frame required by the Hanford Federal Facility Agreement and Consent Order, also known as the Tri-Party Agreement (TPA), i.e. December 31, 2047. Therefore, Supplemental Treatment is required both to meet the TPA treatment requirements as well as to more cost effectively complete the tank waste treatment mission. In addition, the WTP LAW vitrification facility off-gas condensate known as WTP Secondary Waste (WTP-SW) will be generated and enriched in volatile components such as {sup 137}Cs, {sup 129}I, {sup 99}Tc, Cl, F, and SO{sub 4} that volatilize at the vitrification temperature of 1150 C in the absence of a continuous cold cap (that could minimize volatilization). The current waste disposal path for the WTP-SW is to process it through the Effluent Treatment Facility (ETF). Fluidized Bed Steam Reforming (FBSR) is being considered for immobilization of the ETF concentrate that would be generated by processing the WTP-SW. The focus of this current report is the WTP-SW. FBSR offers a moderate temperature (700-750 C) continuous method by which WTP-SW wastes can be processed irrespective of whether they contain organics, nitrates, sulfates/sulfides, chlorides, fluorides, volatile radionuclides or other aqueous components. The FBSR technology can process these wastes into a crystalline ceramic (mineral) waste form. The mineral waste form that is produced by co-processing waste with kaolin clay in an FBSR process has been shown to be as durable as LAW glass. Monolithing of the granular FBSR product is being investigated to prevent dispersion during transport or burial/storage, but is not necessary for performance. A Benchscale Steam Reformer (BSR) was designed and constructed at the SRNL to treat actual radioactive wastes to confirm the findings of the non-radioactive FBSR pilot scale tests and to qualify the waste form for applications at Hanford. BSR testing with WTP SW waste surrogates and associated analytical analyses and tests of granular products (GP) and monoliths began in the Fall of 2009, and then was continued from the Fall of 2010 through the Spring of 2011. Radioactive testing commenced in 2010 with a demonstration of Hanford's WTP-SW where Savannah River Site (SRS) High Level Waste (HLW) secondary waste from the Defense Waste Processing Facility (DWPF) was shimmed with a mixture of {sup 125/129}I and {sup 99}Tc to chemically resemble WTP-SW. Prior to these radioactive feed tests, non-radioactive simulants were also processed. Ninety six grams of radioactive granular product were made for testing and comparison to the non-radioactive pilot scale tests. The same mineral phases were found in the radioactive and non-radioactive testing.« less

LITERATURE REVIEWS TO SUPPORT ION EXCHANGE TECHNOLOGY SELECTION FOR MODULAR SALT PROCESSING

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, W

2007-11-30

This report summarizes the results of literature reviews conducted to support the selection of a cesium removal technology for application in a small column ion exchange (SCIX) unit supported within a high level waste tank. SCIX is being considered as a technology for the treatment of radioactive salt solutions in order to accelerate closure of waste tanks at the Savannah River Site (SRS) as part of the Modular Salt Processing (MSP) technology development program. Two ion exchange materials, spherical Resorcinol-Formaldehyde (RF) and engineered Crystalline Silicotitanate (CST), are being considered for use within the SCIX unit. Both ion exchange materials havemore » been studied extensively and are known to have high affinities for cesium ions in caustic tank waste supernates. RF is an elutable organic resin and CST is a non-elutable inorganic material. Waste treatment processes developed for the two technologies will differ with regard to solutions processed, secondary waste streams generated, optimum column size, and waste throughput. Pertinent references, anticipated processing sequences for utilization in waste treatment, gaps in the available data, and technical comparisons will be provided for the two ion exchange materials to assist in technology selection for SCIX. The engineered, granular form of CST (UOP IE-911) was the baseline ion exchange material used for the initial development and design of the SRS SCIX process (McCabe, 2005). To date, in-tank SCIX has not been implemented for treatment of radioactive waste solutions at SRS. Since initial development and consideration of SCIX for SRS waste treatment an alternative technology has been developed as part of the River Protection Project Waste Treatment Plant (RPP-WTP) Research and Technology program (Thorson, 2006). Spherical RF resin is the baseline media for cesium removal in the RPP-WTP, which was designed for the treatment of radioactive waste supernates and is currently under construction in Hanford, WA. Application of RF for cesium removal in the Hanford WTP does not involve in-riser columns but does utilize the resin in large scale column configurations in a waste treatment facility. The basic conceptual design for SCIX involves the dissolution of saltcake in SRS Tanks 1-3 to give approximately 6 M sodium solutions and the treatment of these solutions for cesium removal using one or two columns supported within a high level waste tank. Prior to ion exchange treatment, the solutions will be filtered for removal of entrained solids. In addition to Tanks 1-3, solutions in two other tanks (37 and 41) will require treatment for cesium removal in the SCIX unit. The previous SCIX design (McCabe, 2005) utilized CST for cesium removal with downflow supernate processing and included a CST grinder following cesium loading. Grinding of CST was necessary to make the cesium-loaded material suitable for vitrification in the SRS Defense Waste Processing Facility (DWPF). Because RF resin is elutable (and reusable) and processing requires conversion between sodium and hydrogen forms using caustic and acidic solutions more liquid processing steps are involved. The WTP baseline process involves a series of caustic and acidic solutions (downflow processing) with water washes between pH transitions across neutral. In addition, due to resin swelling during conversion from hydrogen to sodium form an upflow caustic regeneration step is required. Presumably, one of these basic processes (or some variation) will be utilized for MSP for the appropriate ion exchange technology selected. CST processing involves two primary waste products: loaded CST and decontaminated salt solution (DSS). RF processing involves three primary waste products: spent RF resin, DSS, and acidic cesium eluate, although the resin is reusable and typically does not require replacement until completion of multiple treatment cycles. CST processing requires grinding of the ion exchange media, handling of solids with high cesium loading, and handling of liquid wash and conditioning solutions. RF processing requires handling and evaporation of cesium eluates, disposal of spent organic resin, and handling of the various liquid wash and regenerate solutions used. In both cases, the DSS will be immobilized in a low activity waste form. It appears that both technologies are mature, well studied, and generally suitable for this application. Technology selection will likely be based on downstream impacts or preferences between the various processing options for the two materials rather than on some unacceptable performance property identified for one material. As a result, the following detailed technical review and summary of the two technologies should be useful to assist in technology selection for SCIX.« less

76 FR 40379 - New Proposed Collection; Comment Request; Study Logistic Formative Research Methodology Studies...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-08

...; Comment Request; Study Logistic Formative Research Methodology Studies for the National Children's Study... Collection Title: Study Logistics Formative Research Methodology Studies for the National Children's Study... national longitudinal study of environmental influences (including physical, chemical, biological, and...

Project Notes

ERIC Educational Resources Information Center

School Science Review, 1977

1977-01-01

Listed and described are student A-level biology projects in the following areas: Angiosperm studies (e.g., factors affecting growth of various plants), 7; Bacterial studies, 1; Insect studies, 2; Fish studies, 1; Mammal studies, 1; Human studies, 1; Synecology studies, 2; Environmental studies, 2; and Enzyme studies, 1. (CS)

Agreement studies in radiology research.

PubMed

Farzin, B; Gentric, J-C; Pham, M; Tremblay-Paquet, S; Brosseau, L; Roy, C; Jamali, S; Chagnon, M; Darsaut, T E; Guilbert, F; Naggara, O; Raymond, J

2017-03-01

The goal of this study was to estimate the frequency and the quality of agreement studies published in diagnostic imaging journals. All studies published between January 2011 and December 2012 in four radiology journals were reviewed. Four trained readers evaluated agreement studies using a 24-item form that included the 15 items of the Guidelines for Reporting Reliability and Agreement Studies criteria. Of 2229 source titles, 280 studies (13%) reported agreement. The mean number of patients per study was 81±99 (SD) (range, 0-180). Justification for sample size was found in 9 studies (3%). The number of raters was≤2 in 226 studies (81%). No intra-observer study was performed in 212 (76%) articles. Confidence intervals and interpretation of statistical estimates were provided in 98 (35%) and 147 (53%) of the studies, respectively. In 168 studies (60%), the agreement study was not mentioned in the discussion section. In 8 studies (3%), reporting of the agreement study was judged to be adequate. Twenty studies (7%) were dedicated to agreement. Agreement studies are preliminary and not adequately reported. Studies dedicated to agreement are infrequent. They are research opportunities that should be promoted. Copyright © 2016 Éditions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.

Use of Statins to Augment Progenitor Cell Function in Preclinical and Clinical Studies of Regenerative Therapy: a Systematic Review.

PubMed

Park, Angela; Barrera-Ramirez, Juliana; Ranasinghe, Indee; Pilon, Sophie; Sy, Richmond; Fergusson, Dean; Allan, David S

2016-06-01

Mesenchymal stromal cells (MSCs) and endothelial progenitor cells (EPCs) are used in cell-based regenerative therapy. HMG CoA reductase inhibitors (statins) appear promising in blocking apoptosis, prolonging progenitor cell survival and improving their capacity to repair organ function. We performed a systematic review of preclinical and clinical studies to clarify whether statins can improve cell-based repair of organ injury. MEDLINE, EMBASE, and PUBMED databases were searched (1947 to June 25, 2013). Controlled clinical and pre-clinical studies were included that evaluated statin therapy used alone or in combination with MSCs or EPCs in patients or animals with organ injury. After screening 771 citations, 100 records underwent full eligibility screening of which 38 studies met eligibility and were included in the review: Studies were grouped into pre-clinical studies that involved statin treatment in combination with cell therapy (18 studies), preclinical studies of statin therapy alone (13 studies) and clinical studies of statin therapy (7 studies). Studies addressed cardiac injury (14 studies), vascular disorders (15 studies), neurologic conditions (8 studies) and bone fractures (1 study). Pre-clinical studies of statins in combination with MSC infusion (15 studies) or EPC therapy (3 studies) were described and despite marked heterogeneity in reporting outcomes of cellular analysis and organ function, all of these cell-based pre-clinical studies reported improved organ recovery with the addition of statin therapy. Moreover, 13 pre-clinical studies involved the administration of a statin drug alone to animals. An increase in EPC number and/or function (no studies of MSCs) was reported in 11 of these studies (85 %) and improved organ function in 12 studies (92 %). We also identified 7 clinical studies and none involved the administration of cells but described an increased number and/or function of EPCs (no studies of MSCs) and improved organ function with statin therapy (1.2-fold to 35-fold improvement over controls) in all 7 studies. Our systematic review provides a foundation of encouraging results that support further study of statins in regenerative therapy to augment the number and/or function of MSCs used in cell-based repair and to augment the number and function of EPCs in vivo to repair damaged tissues. Larger studies are needed to ensure safety and confirm clinical benefits.

76 FR 48872 - Proposed Collection; Comment Request; The Hispanic Community Health Study (HCHS)/Study of Latinos...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-09

... Request; The Hispanic Community Health Study (HCHS)/Study of Latinos (SOL) SUMMARY: In compliance with the...: Hispanic Community Health Study (HCHS)/ Study of Latinos (SOL). Type of Information Collection Request... Health Study (HCHS)/Study of Latinos (SOL) will identify risk factors for cardiovascular and lung disease...

Driving clinical study efficiency by using a productivity breakdown model: comparative evaluation of a global clinical study and a similar Japanese study.

PubMed

Takahashi, K; Sengoku, S; Kimura, H

2011-02-01

A fundamental management imperative of pharmaceutical companies is to contain surging costs of developing and launching drugs globally. Clinical studies are a research and development (R&D) cost driver. The objective of this study was to develop a productivity breakdown model, or a key performance indicator (KPI) tree, for an entire clinical study and to use it to compare a global clinical study with a similar Japanese study. We, thereby, hope to identify means of improving study productivity. We developed the new clinical study productivity breakdown model, covering operational aspects and cost factors. Elements for improving clinical study productivity were assessed from a management viewpoint by comparing empirical tracking data from a global clinical study with a Japanese study with similar protocols. The following unique and material differences, beyond simple international difference in cost of living, that could affect the efficiency of future clinical trials were identified: (i) more frequent site visits in the Japanese study, (ii) head counts at the Japanese study sites more than double those of the global study and (iii) a shorter enrollment time window of about a third that of the global study at the Japanese study sites. We identified major differences in the performance of the two studies. These findings demonstrate the potential of the KPI tree for improving clinical study productivity. Trade-offs, such as those between reduction in head count at study sites and expansion of the enrollment time window, must be considered carefully. © 2010 Blackwell Publishing Ltd.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobson, L. O.; Doyle, M.

Abstracts are provided for presentations in these areas: studies in immunology; studies in molecular biology; experimental and clinical studies of cell differentiation; studies on the blood; general metabolic studies; problems in scanning; clinical and experimental studies on the effects of radiation; and studies with high energy radiations.

Investigating Prospective Social Studies Teachers? Perceptions of European Union through Metaphor Analysis

ERIC Educational Resources Information Center

Akgün, Ismail Hakan

2017-01-01

The purpose of this study is to investigate metaphors developed by social studies teacher candidates about the European Union. 185 second, third and fourth year social studies teacher candidates participated in the study. This study was designed as a phenomenological study and mataphor analysis was conducted. At the end of the study, the students…

78 FR 76629 - The National Children's Study, Vanguard (Pilot) Study; Submission for OMB Review; 30-Day Comment...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-18

..., revisions to existing Study visits, and the initiation of methodological substudies. The NCS Vanguard Study... design of the Main Study of the National Children's Study. Background: The National Children's Study is a... questionnaire containing key variables and designed to collect core data at every study visit contact from the...

Social Studies Teachers' Viewpoints of the Social Studies Lesson "Sample of Turkey and Afghanistan"

ERIC Educational Resources Information Center

Sonmez, Omer Faruk

2014-01-01

This study was conducted to reveal the perceptions of history, geography and social studies teachers giving the social studies lesson at primary schools in Turkey and Afghanistan towards the social studies lesson. The working group of the study involves history, geography and social studies teachers rendering service in Tokat and Kayseri provinces…

Observational Studies: Cohort and Case-Control Studies

PubMed Central

Song, Jae W.; Chung, Kevin C.

2010-01-01

Observational studies are an important category of study designs. To address some investigative questions in plastic surgery, randomized controlled trials are not always indicated or ethical to conduct. Instead, observational studies may be the next best method to address these types of questions. Well-designed observational studies have been shown to provide results similar to randomized controlled trials, challenging the belief that observational studies are second-rate. Cohort studies and case-control studies are two primary types of observational studies that aid in evaluating associations between diseases and exposures. In this review article, we describe these study designs, methodological issues, and provide examples from the plastic surgery literature. PMID:20697313

The use of dogs as second species in regulatory testing of pesticides. Part II: Subacute, subchronic and chronic studies in the dog.

PubMed

Spielmann, H; Gerbracht, U

2001-03-01

Data on 172 pesticides (fungicides, herbicides, insecticides and other pesticides) submitted for regulatory purposes during the past 40 years to the German Federal Institute for the Health Protection of Consumers and Veterinary Medicine (BgVV) were analysed to determine whether chronic studies in dogs (52/104 weeks) provide essential additional specific toxicological compared with subchronic (13 weeks) or subacute (4 weeks) studies in the same species. Comparison of the lowest observed effect levels (LOELs) in dogs revealed no significant differences between subchronic and chronic studies but a significant difference between subacute studies and subchronic or chronic studies. Moreover, there was a significant correlation between the LOELs determined in subchronic studies and those determined in chronic studies in dogs (r = 0.78-0.84). The distribution of target organ toxicity determined in chronic studies in dogs was not significantly different from the distribution determined in subchronic studies, except for effects on the spleen in studies on herbicides which were only observed in chronic studies and in combined subchronic/chronic studies, but never in subchronic studies. Organ-specific effects that were observed in chronic studies but not in subchronic studies were found in 30 of 55 studies on fungicides, in 25 of 44 on herbicides, in 17 of 38 on insecticides and in 10 of 16 on other pesticides. Compared with 26-week studies, additional organ-specific toxic effects were found in three of five, in three of four, in one of three and in one of one 52/104-week studies on fungicides, of herbicides, of insecticides and other pesticides, respectively. The organ-specific effects that were seen only in the chronic dog studies were evaluated according to their severity, e.g. significant damage to organs versus changes in enzyme activities that do not affect organ function or histology. Such effects were not considered to be specific for dogs in chronic studies if similar effects were also found in chronic studies in rodents (rat or mouse). In 15 of 141 studies in dogs serious side effects were observed in chronic studies that were not observed in subchronic studies. Furthermore, for 9 of 172 pesticides significant new effects were seen in 52/104-week studies when compared with 4- or 13-week studies and in 7 of 141 52/104-week studies when compared with 13-week studies. Analysis of the severity of organ-specific toxic effects of pesticides revealed that chronic long-term studies (52/104 weeks) in dogs do not provide specific additional information to 26-week studies in the same species.

Supplementary search methods were more effective and offered better value than bibliographic database searching: A case study from public health and environmental enhancement.

PubMed

Cooper, Chris; Lovell, Rebecca; Husk, Kerryn; Booth, Andrew; Garside, Ruth

2018-06-01

We undertook a systematic review to evaluate the health benefits of environmental enhancement and conservation activities. We were concerned that a conventional process of study identification, focusing on exhaustive searches of bibliographic databases as the primary search method, would be ineffective, offering limited value. The focus of this study is comparing study identification methods. We compare (1) an approach led by searches of bibliographic databases with (2) an approach led by supplementary search methods. We retrospectively assessed the effectiveness and value of both approaches. Effectiveness was determined by comparing (1) the total number of studies identified and screened and (2) the number of includable studies uniquely identified by each approach. Value was determined by comparing included study quality and by using qualitative sensitivity analysis to explore the contribution of studies to the synthesis. The bibliographic databases approach identified 21 409 studies to screen and 2 included qualitative studies were uniquely identified. Study quality was moderate, and contribution to the synthesis was minimal. The supplementary search approach identified 453 studies to screen and 9 included studies were uniquely identified. Four quantitative studies were poor quality but made a substantive contribution to the synthesis; 5 studies were qualitative: 3 studies were good quality, one was moderate quality, and 1 study was excluded from the synthesis due to poor quality. All 4 included qualitative studies made significant contributions to the synthesis. This case study found value in aligning primary methods of study identification to maximise location of relevant evidence. Copyright © 2017 John Wiley & Sons, Ltd.

Student Use of Out-of-Class Study Groups in an Introductory Undergraduate Biology Course

PubMed Central

Rybczynski, Stephen M.; Schussler, Elisabeth E.

2011-01-01

Self-formed out-of-class study groups may benefit student learning; however, few researchers have quantified the relationship between study group use and achievement or described changes in study group usage patterns over a semester. We related study group use to performance on content exams, explored patterns of study group use, and qualitatively described student perceptions of study groups. A pre- and posttest were used to measure student content knowledge. Internet-based surveys were used to collect quantitative data on exam performance and qualitative data on study group usage trends and student perceptions of study groups. No relationship was found between gains in content knowledge and study group use. Students who participated in study groups did, however, believe they were beneficial. Four patterns of study group use were identified: students either always (14%) or never (55%) used study groups, tried but quit using them (22%), or utilized study groups only late in the semester (9%). Thematic analysis revealed preconceptions and in-class experiences influence student decisions to utilize study groups. We conclude that students require guidance in the successful use of study groups. Instructors can help students maximize study group success by making students aware of potential group composition problems, helping students choose group members who are compatible, and providing students materials on which to focus their study efforts. PMID:21364102

The value of including observational studies in systematic reviews was unclear: a descriptive study.

PubMed

Seida, Jennifer; Dryden, Donna M; Hartling, Lisa

2014-12-01

To evaluate (1) how often observational studies are included in comparative effectiveness reviews (CERs); (2) the rationale for including observational studies; (3) how data from observational studies are appraised, analyzed, and graded; and (4) the impact of observational studies on strength of evidence (SOE) and conclusions. Descriptive study of 23 CERs published through the Effective Health Care Program of the U.S. Agency for Healthcare Research and Quality. Authors searched for observational studies in 20 CERs, of which 18 included a median of 11 (interquartile range, 2-31) studies. Sixteen CERs incorporated the observational studies in their SOE assessments. Seventy-eight comparisons from 12 CERs included evidence from both trials and observational studies; observational studies had an impact on SOE and conclusions for 19 (24%) comparisons. There was diversity across the CERs regarding decisions to include observational studies; study designs considered; and approaches used to appraise, synthesize, and grade SOE. Reporting and methods guidance are needed to ensure clarity and consistency in how observational studies are incorporated in CERs. It was not always clear that observational studies added value in light of the additional resources needed to search for, select, appraise, and analyze such studies. Copyright © 2014 Elsevier Inc. All rights reserved.

Length of Study-Time Behaviour and Academic Achievement of Social Studies Education Students in the University of Uyo

ERIC Educational Resources Information Center

Ukpong, D. E.; George, I. N.

2013-01-01

This study investigated the length of study time behaviour and academic achievement of Social Studies Education students in the University of Uyo. The purpose was to determine the difference in the academic achievement of the long study time behaviour students and their short study time behaviour counterparts in Social Studies Education. The study…

Water-quality assessment of part of the Upper Mississippi River Basin, Minnesota and Wisconsin - Ground-water quality in three different land-use areas, 1996-98

USGS Publications Warehouse

Fong, Alison L.

2000-01-01

Comparisons of previous land-use studies in Minnesota with the three NAWQA land-use studies generally indicated the same patterns. Ground-water quality in surficial sand and gravel aquifers is affected by land-use practices. Ground water in urban studies has greater specific conductances, alkalinities, chloride, sodium, sulfate, and dissolved solid concentrations than agricultural or forested/undeveloped studies. Nitrate-nitrogen was detected in greater concentrations in agricultural studies than in urban studies, with concentrations in the forested/undeveloped studies less than in the agricultural or the urban studies. Agricultural studies have the greatest detection rates, numbers, and total concentrations of pesticides. Pesticide detection rates and total pesticide concentrations in the urban studies were less than in the agricultural studies, with the most frequently detected pesticides (prometon and dicamba) different than those in the agricultural studies (atrazine and deethylatrazine). A greater number of VOCs were detected in urban studies and at greater concentrations than in agricultural studies. Few pesticides or VOCs were detected in forested/undeveloped studies.

77 FR 70451 - Proposed Collection; Comment Request; Methodological Studies for the Population Assessment of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-26

... Request; Methodological Studies for the Population Assessment of Tobacco and Health (PATH) Study SUMMARY... Collection: Title: Methodological Studies for Population Assessment of Tobacco and Health (PATH) Study. Type... methodological studies to improve the PATH study instrumentation and data collection procedures. These...

Four Futures for Social Studies.

ERIC Educational Resources Information Center

Morrissett, Irving

The current status of social studies education provides information for assessing and predicting future trends in social studies education. A 3-year study, "Social Studies Priorities and Needs," found that: social studies/social science educators are concerned with constructing a rationale and definition of social studies; the dominant approach to…

Impact of study outcome on submission and acceptance metrics for peer reviewed medical journals: six year retrospective review of all completed GlaxoSmithKline human drug research studies.

PubMed

Evoniuk, Gary; Mansi, Bernadette; DeCastro, Barbara; Sykes, Jennie

2017-04-21

Objectives  To determine whether the outcome of drug studies influenced submission and/or acceptance rates for publication in peer reviewed medical journals. Design  A six year retrospective review of publication status by study outcome for all human drug research studies conducted by a single industry sponsor (GlaxoSmithKline) that completed from 1 January 2009 to 30 June 2014 and were therefore due for manuscript submission (per the sponsor's policy) to peer reviewed journals within 18 months of study completion-that is, 31 December 2015. In addition, manuscripts from studies completing after 30 June 2014 were included irrespective of outcome if they were submitted before 31 December 2015. Setting  Studies conducted by a single industry sponsor (GlaxoSmithKline) Studies reviewed  1064 human drug research studies. Main outcome measures  All studies were assigned a publication status at 26 February 2016 including (as applicable): study completion date, date of first primary manuscript submission, number of submissions, journal decision(s), and publication date. All studies were also classified with assessors blinded to publication status as "positive" (perceived favorable outcome for the drug under study), "negative" (perceived unfavorable outcome for the drug under study), mixed, or non-comparative based on the presence and outcome of the primary outcome measure(s) for each study. "Negative" studies included safety studies in which the primary outcome was achieved but was adverse for the drug under study. For the total cohort and each of the four study outcomes, measures included descriptive statistics for study phase, time from study completion to submission and publication, and number and outcome (accepted/rejected) of publication submissions. Results  Of the 1064 studies (phase I-IV, interventional and non-interventional) included, 321 had study outcomes classified as positive, 155 as negative, 52 as mixed, and 536 as non-comparative. At the time of publication cut-off date (26 February 2016), 904 (85%) studies had been submitted for publication as full manuscripts and 751 (71%) had been successfully published or accepted, with 100 (9%) still under journal review. An additional 77 (7%) studies were conference abstracts and were not included in submission or publication rates. Submission rates by study outcome were 79% for the 321 studies with positive outcomes, 92% for the 155 with negative outcomes, 94% for the 52 with mixed outcomes, and 85% for the 536 non-comparative studies; while rates of publication at the cut-off date were 66%, 77%, 77%, and 71%, respectively. Median time from study completion to submission was 537 days (interquartile range 396-638 days) and 823 days (650-1063 days) from completion to publication, with similar times observed across study outcomes. First time acceptance rates were 56% for studies with positive outcomes and 48% for studies with negative outcomes. Over 10% of studies across all categories required three or more submissions to achieve successful publication. At the time of analysis, 83 studies had not been submitted for publication, including 49 bioequivalence studies with positive outcomes and 33 non-comparative studies. Most studies (98%, 1041/1064) had results posted to one or more public registers, including all studies subject to FDAAA (Food and Drug Administration Amendments Act) requirements for posting to www.clinicaltrials.gov Conclusions  Over the period studied, there was no evidence of submission or publication bias: 92% of studies with negative outcomes were submitted for publication by the cut-off date versus 79% of those with positive outcomes. Publication rates were slightly higher for studies with a negative (that is, unfavorable) outcome compared with a positive outcome, despite a slightly lower rate of acceptance at first submission. Many studies required multiple submission attempts before they were accepted for publication. Analyses focusing solely on publication rates do not take into account unsuccessful efforts to publish. Sponsors and journal editors should share similar information to contribute to better understanding of issues and barriers to full transparency. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

How Do the Different Study Profiles of First-Year Students Predict Their Study Success, Study Progress and the Completion of Degrees?

ERIC Educational Resources Information Center

Haarala-Muhonen, Anne; Ruohoniemi, Mirja; Parpala, Anna; Komulainen, Erkki; Lindblom-Ylänne, Sari

2017-01-01

The relationship between study success and the nature of 550 first-year law students' study processes was investigated using a modified version of the Approaches to Learning and Studying Inventory. The students were classified into four study profiles according to their approaches to learning, indicating the nature of their study processes. In…

Overview of registered studies in orthodontics: Evaluation of the ClinicalTrials.gov registry.

PubMed

Allareddy, Veerasathpurush; Rampa, Sankeerth; Masoud, Mohamed I; Lee, Min Kyeong; Nalliah, Romesh; Allareddy, Veerajalandhar

2014-11-01

The Food and Drug Administration Modernization Act of 1997 made it mandatory for all phase II through IV trials regulated by this Act to be registered. After this, the National Institutes of Health created ClinicalTrials.gov, which is a registry of publicly and privately supported clinical studies of human participants. The objective of this study was to examine the characteristics of registered studies in orthodontics. The ClinicalTrials.gov Web site was used to query all registered orthodontic studies. The search term used was "orthodontics." No limitations were placed for the time period. All registered studies regardless of their recruitment status, study results, and study type were selected for analysis. A total of 64 orthodontic studies were registered as of January 1, 2014. Of these, 52 were interventional, and 12 were observational. Close to 60% of the interventional studies and 66.7% of the observational studies had sample sizes of 50 or fewer subjects. About 21.2% of the interventional studies and 16.7% of the observational studies had sample sizes greater than 100. Only 1 study was funded by the National Institutes of Health, and the rest were funded by "other" or "industry" sources. Close to 87.7% of the interventional studies were randomized. Interventional model assignments included factorial assignment (3.9%), parallel assignments (74.5%), crossover assignment (7.8%), and single-group assignment (13.7%). Most studies were treatment oriented (80.4%). The types of masking used by the interventional studies included open label (28.9%), single blind (44.2%), and double blind (26.9%). Outcome assessors were blinded in only 6 studies. Orthodontic studies registered in ClinicalTrials.gov are dominated by small single-center studies. There are wide variations with regard to treatment allocation approaches and randomization methods in the studies. These results also indicate the need for multicenter clinical studies in orthodontics. Copyright © 2014 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

78 FR 12335 - Submission for OMB review; Comment Request: Methodological Studies for the Population Assessment...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-22

...; Comment Request: Methodological Studies for the Population Assessment of Tobacco and Health (PATH) Study... approval from OMB for methodological studies to improve the PATH study instrumentation and data collection procedures. These methodological studies will support ongoing assessment and refinement of the PATH study's...

Contemporary Social Studies: An Essential Reader. Teaching and Learning Social Studies

ERIC Educational Resources Information Center

Russell, William B., III, Ed.

2012-01-01

The field of social studies is unique and complex. It is challenged by the differing perspectives related to the definition, goals, content, and purpose of social studies. Contemporary Social Studies: An Essential Reader discusses the contemporary issues surrounding social studies education today. Contemporary Social Studies: An Essential Reader…

Variation in Study Patterns among College Students: A Review of Literature

ERIC Educational Resources Information Center

Lei, Simon A.

2015-01-01

An effective studying strategy requires developed personalized study skills to increase student success and retention at the college level. Within these personalized study skills, different students have developed different study habits and environments (study patterns). Yet, the study patterns of people who have achieved outstanding academic…

Dental Student Study Strategies: Are Self-Testing and Scheduling Related to Academic Performance?

PubMed

McAndrew, Maureen; Morrow, Christina S; Atiyeh, Lindsey; Pierre, Gaëlle C

2016-05-01

Self-testing, a strategy wherein a student actively engages in creating questions and answers from study materials to assist with studying, has been found to be especially advantageous because it enhances future retrieval of information. Studies have found correlations among students' grade point averages (GPAs), self-testing, and rereading study strategies, as well as the spacing of study sessions over time. The aim of this study was to assess relationships among dental students' study strategies, scheduling of study time, and academic achievement. A 16-item survey requesting information on study habits, study schedules, and GPAs was distributed to 358 second-year dental students at New York University College of Dentistry. Additionally, the survey asked students to report the average number of hours per week they devoted to studying for didactic courses and preparing for hands-on preclinical courses. Of the 358 students, 94 (26%) responded to the survey. The vast majority of the respondents reported utilizing self-testing and rereading study strategies. High performers (with higher GPAs) were more likely to use self-testing, especially with flashcards, and to space their studying over multiple sessions. Lower performing students were more likely to highlight or underline their notes and to mass their study sessions or cram. Longer hours devoted to studying and practicing for simulation courses were associated with stronger performance; lower performers reported spending significantly fewer hours practicing for simulation courses. Half of the dental students surveyed said that they felt their studying would be more productive in the morning, although 84% reported doing most of their studying in the evening or late night. Sound study decisions depend on accurate regulation of ongoing learning and appropriate use and timing of evidence-based study strategies, so these results suggest that dental students may require guidance in these areas.

Overdiagnosis across medical disciplines: a scoping review

PubMed Central

de Groot, Joris A H; Reitsma, Johannes B; Moons, Karel G M; Hooft, Lotty; Naaktgeboren, Christiana A

2017-01-01

Objective To provide insight into how and in what clinical fields overdiagnosis is studied and give directions for further applied and methodological research. Design Scoping review. Data sources Medline up to August 2017. Study selection All English studies on humans, in which overdiagnosis was discussed as a dominant theme. Data extraction Studies were assessed on clinical field, study aim (ie, methodological or non-methodological), article type (eg, primary study, review), the type and role of diagnostic test(s) studied and the context in which these studies discussed overdiagnosis. Results From 4896 studies, 1851 were included for analysis. Half of all studies on overdiagnosis were performed in the field of oncology (50%). Other prevalent clinical fields included mental disorders, infectious diseases and cardiovascular diseases accounting for 9%, 8% and 6% of studies, respectively. Overdiagnosis was addressed from a methodological perspective in 20% of studies. Primary studies were the most common article type (58%). The type of diagnostic tests most commonly studied were imaging tests (32%), although these were predominantly seen in oncology and cardiovascular disease (84%). Diagnostic tests were studied in a screening setting in 43% of all studies, but as high as 75% of all oncological studies. The context in which studies addressed overdiagnosis related most frequently to its estimation, accounting for 53%. Methodology on overdiagnosis estimation and definition provided a source for extensive discussion. Other contexts of discussion included definition of disease, overdiagnosis communication, trends in increasing disease prevalence, drivers and consequences of overdiagnosis, incidental findings and genomics. Conclusions Overdiagnosis is discussed across virtually all clinical fields and in different contexts. The variability in characteristics between studies and lack of consensus on overdiagnosis definition indicate the need for a uniform typology to improve coherence and comparability of studies on overdiagnosis. PMID:29284720

Systematic review of the quality of prognosis studies in systemic lupus erythematosus.

PubMed

Lim, Lily S H; Lee, Senq J; Feldman, Brian M; Gladman, Dafna D; Pullenayegum, Eleanor; Uleryk, Elizabeth; Silverman, Earl D

2014-10-01

Prognosis studies examine outcomes and/or seek to identify predictors or factors associated with outcomes. Many prognostic factors have been identified in systemic lupus erythematosus (SLE), but few have been consistently found across studies. We hypothesized that this is due to a lack of rigor of study designs. This study aimed to systematically assess the methodologic quality of prognosis studies in SLE. A search of prognosis studies in SLE was performed using MEDLINE and Embase, from January 1990 to June 2011. A representative sample of 150 articles was selected using a random number generator and assessed by 2 reviewers. Each study was assessed by a risk of bias tool according to 6 domains: study participation, study attrition, measurement of prognostic factors, measurement of outcomes, measurement/adjustment for confounders, and appropriateness of statistical analysis. Information about missing data was also collected. A cohort design was used in 71% of studies. High risk of bias was found in 65% of studies for confounders, 57% for study participation, 56% for attrition, 36% for statistical analyses, 20% for prognostic factors, and 18% for outcome. Missing covariate or outcome information was present in half of the studies. Only 6 studies discussed reasons for missing data and 2 imputed missing data. Lack of rigorous study design, especially in addressing confounding, study participation and attrition, and inadequately handled missing data, has limited the quality of prognosis studies in SLE. Future prognosis studies should be designed with consideration of these factors to improve methodologic rigor. Copyright © 2014 by the American College of Rheumatology.

Methodology Series Module 1: Cohort Studies

PubMed Central

Setia, Maninder Singh

2016-01-01

Cohort design is a type of nonexperimental or observational study design. In a cohort study, the participants do not have the outcome of interest to begin with. They are selected based on the exposure status of the individual. They are then followed over time to evaluate for the occurrence of the outcome of interest. Some examples of cohort studies are (1) Framingham Cohort study, (2) Swiss HIV Cohort study, and (3) The Danish Cohort study of psoriasis and depression. These studies may be prospective, retrospective, or a combination of both of these types. Since at the time of entry into the cohort study, the individuals do not have outcome, the temporality between exposure and outcome is well defined in a cohort design. If the exposure is rare, then a cohort design is an efficient method to study the relation between exposure and outcomes. A retrospective cohort study can be completed fast and is relatively inexpensive compared with a prospective cohort study. Follow-up of the study participants is very important in a cohort study, and losses are an important source of bias in these types of studies. These studies are used to estimate the cumulative incidence and incidence rate. One of the main strengths of a cohort study is the longitudinal nature of the data. Some of the variables in the data will be time-varying and some may be time independent. Thus, advanced modeling techniques (such as fixed and random effects models) are useful in analysis of these studies. PMID:26955090

Methodology Series Module 1: Cohort Studies.

PubMed

Setia, Maninder Singh

2016-01-01

Cohort design is a type of nonexperimental or observational study design. In a cohort study, the participants do not have the outcome of interest to begin with. They are selected based on the exposure status of the individual. They are then followed over time to evaluate for the occurrence of the outcome of interest. Some examples of cohort studies are (1) Framingham Cohort study, (2) Swiss HIV Cohort study, and (3) The Danish Cohort study of psoriasis and depression. These studies may be prospective, retrospective, or a combination of both of these types. Since at the time of entry into the cohort study, the individuals do not have outcome, the temporality between exposure and outcome is well defined in a cohort design. If the exposure is rare, then a cohort design is an efficient method to study the relation between exposure and outcomes. A retrospective cohort study can be completed fast and is relatively inexpensive compared with a prospective cohort study. Follow-up of the study participants is very important in a cohort study, and losses are an important source of bias in these types of studies. These studies are used to estimate the cumulative incidence and incidence rate. One of the main strengths of a cohort study is the longitudinal nature of the data. Some of the variables in the data will be time-varying and some may be time independent. Thus, advanced modeling techniques (such as fixed and random effects models) are useful in analysis of these studies.

Methodology Series Module 3: Cross-sectional Studies.

PubMed

Setia, Maninder Singh

2016-01-01

Cross-sectional study design is a type of observational study design. In a cross-sectional study, the investigator measures the outcome and the exposures in the study participants at the same time. Unlike in case-control studies (participants selected based on the outcome status) or cohort studies (participants selected based on the exposure status), the participants in a cross-sectional study are just selected based on the inclusion and exclusion criteria set for the study. Once the participants have been selected for the study, the investigator follows the study to assess the exposure and the outcomes. Cross-sectional designs are used for population-based surveys and to assess the prevalence of diseases in clinic-based samples. These studies can usually be conducted relatively faster and are inexpensive. They may be conducted either before planning a cohort study or a baseline in a cohort study. These types of designs will give us information about the prevalence of outcomes or exposures; this information will be useful for designing the cohort study. However, since this is a 1-time measurement of exposure and outcome, it is difficult to derive causal relationships from cross-sectional analysis. We can estimate the prevalence of disease in cross-sectional studies. Furthermore, we will also be able to estimate the odds ratios to study the association between exposure and the outcomes in this design.

Methodology Series Module 3: Cross-sectional Studies

PubMed Central

Setia, Maninder Singh

2016-01-01

Cross-sectional study design is a type of observational study design. In a cross-sectional study, the investigator measures the outcome and the exposures in the study participants at the same time. Unlike in case–control studies (participants selected based on the outcome status) or cohort studies (participants selected based on the exposure status), the participants in a cross-sectional study are just selected based on the inclusion and exclusion criteria set for the study. Once the participants have been selected for the study, the investigator follows the study to assess the exposure and the outcomes. Cross-sectional designs are used for population-based surveys and to assess the prevalence of diseases in clinic-based samples. These studies can usually be conducted relatively faster and are inexpensive. They may be conducted either before planning a cohort study or a baseline in a cohort study. These types of designs will give us information about the prevalence of outcomes or exposures; this information will be useful for designing the cohort study. However, since this is a 1-time measurement of exposure and outcome, it is difficult to derive causal relationships from cross-sectional analysis. We can estimate the prevalence of disease in cross-sectional studies. Furthermore, we will also be able to estimate the odds ratios to study the association between exposure and the outcomes in this design. PMID:27293245

U.S. Geological Survey ground-water studies in Florida

USGS Publications Warehouse

Vecchioli, John

1988-01-01

The first groundwater study by the U.S. Geological Survey (USGS) in Florida began in 1910. In 1930, a cooperative program of study was started with the Florida Geological Survey, and in 1938, the first groundwater office of the USGS was established in Miami. In fiscal year 1987, the USGS program in Florida included 35 active groundwater studies, all of which dealt with at least one of the principal groundwater issues. The 35 active studies were divided among the issues as follows: groundwater quality management, 9 studies; groundwater availability, 12 studies; seawater intrusion, 3 studies; contamination from wastewater disposal, 6 studies; contamination from landfills and hazardous waste sites, 3 studies; and contamination from agricultural practices, 2 studies. (Lantz-PTT)

The geographic location (latitude) of studies evaluating protective effect of BCG vaccine and it's efficacy/effectiveness against tuberculosis.

PubMed

Zodpey, Sanjay P; Shrikhande, Sunanda N

2007-01-01

To study association between the geographic location (latitude) of studies evaluating protective effect of BCG vaccine and it's efficacy / effectiveness against tuberculosis. A comprehensive literature search was carried out to identify relevant studies. Data extraction from these studies included place of study (geographic latitude), study design and reported point estimate of protective effect of BCG vaccine against tuberculosis. Information on latitude was obtained from Oxford School Atlas for World Geography. A spearman rank correlation coefficient was estimated to study the association between the latitude of studies and protective effect of BCG vaccine. The Spearman's rank correlation coefficient was significant for all studies grouped together & trials and marginally non-significant for other observational studies. However it was not statistically significant for case-control studies and cohort studies. Overall rho (for 80 studies) between latitude and protective effect of BCG was calculated to be 0.3853 (p = 0.0004). The results thus demonstrated that, in general BCG appeared to provide greater protection at higher latitudes. Thus a correlation coefficient of 0.3853 between latitude and protective effect would indicate that (0.3853)(2) or 15% of the variance in protective effect was accounted for by latitude. The study recognized an association between geographic locations of studies and reported protective effects of BCG vaccine against tuberculosis.

Groundwater quality in the Delaware and St. Lawrence River Basins, New York, 2010

USGS Publications Warehouse

Nystrom, Elizabeth A.

2012-01-01

Water quality in both study areas is generally good, but concentrations of some constituents equaled or exceeded current or proposed Federal or New York State drinking-water standards. The standards exceeded are color (one sample in the St. Lawrence study area), pH (three samples in the Delaware study area), sodium (one sample in the St. Lawrence study area), total dissolved solids (one sample in the St. Lawrence study area), aluminum (one sample in the Delaware study area and one sample in the St. Lawrence study area), iron (seven samples in the St. Lawrence study area), manganese (one sample in the Delaware study area and five samples in the St. Lawrence study area), gross alpha radioactivity (one sample in the St. Lawrence study area), radon-222 (10 samples in the Delaware study area and 14 samples in the St. Lawrence study area), and bacteria (5 samples in the Delaware study area and 10 samples in the St. Lawrence study area). E. coli bacteria were detected in samples from two wells in the St. Lawrence study area. Concentrations of chloride, fluoride, sulfate, nitrate, nitrite, antimony, arsenic, barium, beryllium, cadmium, chromium, copper, lead, mercury, selenium, silver, thallium, zinc, and uranium did not exceed existing drinking-water standards in any of the samples collected.

Research Methods in Healthcare Epidemiology and Antimicrobial Stewardship-Observational Studies.

PubMed

Snyder, Graham M; Young, Heather; Varman, Meera; Milstone, Aaron M; Harris, Anthony D; Munoz-Price, Silvia

2016-10-01

Observational studies compare outcomes among subjects with and without an exposure of interest, without intervention from study investigators. Observational studies can be designed as a prospective or retrospective cohort study or as a case-control study. In healthcare epidemiology, these observational studies often take advantage of existing healthcare databases, making them more cost-effective than clinical trials and allowing analyses of rare outcomes. This paper addresses the importance of selecting a well-defined study population, highlights key considerations for study design, and offers potential solutions including biostatistical tools that are applicable to observational study designs. Infect Control Hosp Epidemiol 2016;1-6.

Systematic review of communication partner training in aphasia: methodological quality.

PubMed

Cherney, Leora R; Simmons-Mackie, Nina; Raymer, Anastasia; Armstrong, Elizabeth; Holland, Audrey

2013-10-01

Twenty-three studies identified from a previous systematic review examining the effects of communication partner training on persons with aphasia and their communication partners were evaluated for methodological quality. Two reviewers rated the studies on defined methodological quality criteria relevant to each study design. There were 11 group studies, seven single-subject participant design studies, and five qualitative studies. Quality scores were derived for each study. The mean inter-rater reliability of scores for each study design ranged from 85-93%, with Cohen's Kappa indicating substantial agreement between raters. Methodological quality of research on communication partner training in aphasia was highly varied. Overall, group studies employed the least rigorous methodology as compared to single subject and qualitative research. Only two of 11 group studies complied with more than half of the quality criteria. No group studies reported therapist blinding and only one group study reported participant blinding. Across all types of studies, the criterion of treatment fidelity was most commonly omitted. Failure to explicitly report certain methodological quality criteria may account for low ratings. Using methodological rating scales specific to the type of study design may help improve the methodological quality of aphasia treatment studies, including those on communication partner training.

Meta-analyses of animal studies: an introduction of a valuable instrument to further improve healthcare.

PubMed

Hooijmans, Carlijn R; IntHout, Joanna; Ritskes-Hoitinga, Merel; Rovers, Maroeska M

2014-01-01

In research aimed at improving human health care, animal studies still play a crucial role, despite political and scientific efforts to reduce preclinical experimentation in laboratory animals. In animal studies, the results and their interpretation are not always straightforward, as no single study is executed perfectly in all steps. There are several possible sources of bias, and many animal studies are replicates of studies conducted previously. Use of meta-analysis to combine the results of studies may lead to more reliable conclusions and a reduction of unnecessary duplication of animal studies. In addition, due to the more exploratory nature of animal studies as compared to clinical trials, meta-analyses of animal studies have greater potential in exploring possible sources of heterogeneity. There is an abundance of literature on how to perform meta-analyses on clinical data. Animal studies, however, differ from clinical studies in some aspects, such as the diversity of animal species studied, experimental design, and study characteristics. In this paper, we will discuss the main principles and practices for meta-analyses of experimental animal studies. © The Author 2014. Published by Oxford University Press.

18 CFR 5.13 - Revised study plan and study plan determination.

Code of Federal Regulations, 2014 CFR

2014-04-01

... differences over study requests. If the potential applicant does not adopt a requested study, it must explain... deadline for filing comments on the potential applicant's proposed study plan, as provided for in § 5.12, the potential applicant must file a revised study plan for Commission approval. The revised study plan...

18 CFR 5.13 - Revised study plan and study plan determination.

Code of Federal Regulations, 2013 CFR

2013-04-01

... differences over study requests. If the potential applicant does not adopt a requested study, it must explain... deadline for filing comments on the potential applicant's proposed study plan, as provided for in § 5.12, the potential applicant must file a revised study plan for Commission approval. The revised study plan...

18 CFR 5.13 - Revised study plan and study plan determination.

Code of Federal Regulations, 2012 CFR

2012-04-01

... differences over study requests. If the potential applicant does not adopt a requested study, it must explain... deadline for filing comments on the potential applicant's proposed study plan, as provided for in § 5.12, the potential applicant must file a revised study plan for Commission approval. The revised study plan...

Social Studies Student Teachers' Levels of Understanding Sociology Concepts within Social Studies Curriculum

ERIC Educational Resources Information Center

Karatekin, Kadir

2013-01-01

This study aims at investigating social studies student teachers' levels of understanding sociology concepts within social studies curriculum. Study group of the research consists of 266 teacher candidates attending the Department of Social Studies, Faculty of Education, Kastamonu University during 2012 to 2013 education year. A semi-structured…

Fostering Effective Studying and Study Planning with Study Questions

ERIC Educational Resources Information Center

Wilhelm, Pascal; Pieters, Jules M.

2007-01-01

In a course on biological psychology and neuropsychology, study questions were provided that also appeared as test questions in the course exam. This method was introduced to support students in active processing and reproduction of the study texts, and study planning. Data were gathered to test the hypothesis that study question use would be…

Social Studies Teachers' In-Service Training Needs towards Project Tasks: A Comparative Case Study

ERIC Educational Resources Information Center

Uyar, Melis Yesilpinar; Karakus, Fatma

2017-01-01

This study aims to determine in-service training needs of novice and professionally experienced social studies teachers regarding the planning, implementation and assessment processes of project tasks. The study was carried out using comparative case study from qualitative research patterns as base. Eight social studies teachers who were…

18 CFR 5.11 - Potential Applicant's proposed study plan and study plan meetings.

Code of Federal Regulations, 2010 CFR

2010-04-01

... proposed study plan and study plan meetings. 5.11 Section 5.11 Conservation of Power and Water Resources... INTEGRATED LICENSE APPLICATION PROCESS § 5.11 Potential Applicant's proposed study plan and study plan..., including information and study requests, the potential applicant must file with the Commission a proposed...

18 CFR 5.11 - Potential Applicant's proposed study plan and study plan meetings.

Code of Federal Regulations, 2011 CFR

2011-04-01

... proposed study plan and study plan meetings. 5.11 Section 5.11 Conservation of Power and Water Resources... INTEGRATED LICENSE APPLICATION PROCESS § 5.11 Potential Applicant's proposed study plan and study plan..., including information and study requests, the potential applicant must file with the Commission a proposed...

A Model of Microteaching Lesson Study Implementation in the Prospective History Teacher Education

ERIC Educational Resources Information Center

Utami, Indah Wahyu Puji; Mashuri; Nafi'ah, Ulfatun

2016-01-01

Microteaching lesson study is a model to improve prospective teacher quality by incorporating several element of microteaching and lesson study. This study concern on the implementation of microteaching lesson study in prospective history teacher education. Microteaching lesson study model implemented in this study consist of three stages: plan,…

Exemplary Social Studies Teachers Use of Computer-Supported Instruction in the Classroom

ERIC Educational Resources Information Center

Acikalin, Mehmet

2010-01-01

Educators increasingly support the use of computer-supported instruction in social studies education. However few studies have been conducted to study teacher use of computer-supported instruction in social studies education. This study was therefore designed to examine the use of exemplary social studies teachers' computer-supported instruction…

Watching MOOCs Together: Investigating Co-Located MOOC Study Groups

ERIC Educational Resources Information Center

Li, Nan; Verma, Himanshu; Skevi, Afroditi; Zufferey, Guillaume; Blom, Jan; Dillenbourg, Pierre

2014-01-01

Research suggests that massive open online course (MOOC) students prefer to study in groups, and that social facilitation within the study groups may render the learning of difficult concepts a pleasing experience. We report on a longitudinal study that investigates how co-located study groups watch and study MOOC videos together. The study was…

Comparative Study of Physics Curriculum in Iran with Several Other Countries

ERIC Educational Resources Information Center

Shekarbaghani, Ashrafoalsadat

2016-01-01

This article is a qualitative study, which was done in 2013-2014. In this study using a comparative study was conducted to compare physics curriculum elements of Iran with the countries studied. Countries studied: Singapore, Turkey, India, England and Australia have diverse educational system. In this study, the structure of the educational…

A Study of Learning Strategies in Foreign Language Instruction: Findings of the Longitudinal Study.

ERIC Educational Resources Information Center

Chamot, Anna Uhl; And Others

Part of a larger research project, this longitudinal study analyzed differences between effective and ineffective high school and college language learners and changes in strategy uses over time. Related studies include a descriptive study, which identified learning strategies used in studying foreign languages, and a course development study, in…

India Renewable Integration Study | Energy Analysis | NREL

Science.gov Websites

India Renewable Integration Study India Renewable Integration Study An NREL grid integration study Energy into India's Electric Grid Vol. I-National Study and Vol. II-Regional Study resolves many system modeling, the study explored operational impacts of meeting India's 2022 targets and identified

Hyperbaric oxygen treatment for inflammatory bowel disease: a systematic review and analysis

PubMed Central

2012-01-01

Background Traditionally, hyperbaric oxygen treatment (HBOT) has been used to treat a limited repertoire of disease, including decompression sickness and healing of problem wounds. However, some investigators have used HBOT to treat inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis. Methods Comprehensive searches were conducted in 8 scientific databases through 2011 to identify publications using HBOT in IBD. Human studies and animal models were collated separately. Results Thirteen studies of HBOT in Crohn's disease and 6 studies in ulcerative colitis were identified. In all studies, participants had severe disease refractory to standard medical treatments, including corticosteroids, immunomodulators and anti-inflammatory medications. In patients with Crohn's disease, 31/40 (78%) had clinical improvements with HBOT, while all 39 patients with ulcerative colitis improved. One study in Crohn's disease reported a significant decrease in proinflammatory cytokines (IL-1, IL-6 and TNF-alpha) and one study in ulcerative colitis reported a decrease in IL-6 with HBOT. Adverse events were minimal. Twelve publications reported using HBOT in animal models of experimentally-induced IBD, including several studies reporting decreased markers of inflammation or immune dysregulation, including TNF-alpha (3 studies), IL-1beta (2 studies), neopterin (1 study) and myeloperoxidase activity (5 studies). HBOT also decreased oxidative stress markers including malondialdehyde (3 studies) and plasma carbonyl content (2 studies), except for one study that reported increased plasma carbonyl content. Several studies reported HBOT lowered nitric oxide (3 studies) and nitric oxide synthase (3 studies) and one study reported a decrease in prostaglandin E2 levels. Four animal studies reported decreased edema or colonic tissue weight with HBOT, and 8 studies reported microscopic improvements on histopathological examination. Although most publications reported improvements with HBOT, some studies suffered from limitations, including possible publication and referral biases, the lack of a control group, the retrospective nature and a small number of participants. Conclusions HBOT lowered markers of inflammation and oxidative stress and ameliorated IBD in both human and animal studies. Most treated patients were refractory to standard medical treatments. Additional studies are warranted to investigate the effects of HBOT on biomarkers of oxidative stress and inflammation as well as clinical outcomes in individuals with IBD. PMID:22417628

A Multi-Study Analysis of Conceptual and Measurement Issues Related to Health Research on Acculturation in Latinos

PubMed Central

Andrews, Arthur R.; Bridges, Ana J.; Gomez, Debbie

2014-01-01

Purpose The aims of the study were to evaluate the orthogonality of acculturation for Latinos. Design Regression analyses were used to examine acculturation in two Latino samples (N = 77; N = 40). In a third study (N = 673), confirmatory factor analyses compared unidimensional and bidimensional models. Method Acculturation was assessed with the ARSMA-II (Studies 1 and 2), and language proficiency items from the Children of Immigrants Longitudinal Study (Study 3). Results In Studies 1 and 2, the bidimensional model accounted for slightly more variance (R2Study 1 = .11; R2Study 2 = .21) than the unidimensional model (R2Study 1 = .10; R2Study 2 = .19). In Study 3, the bidimensional model evidenced better fit (Akaike information criterion = 167.36) than the unidimensional model (Akaike information criterion = 1204.92). Discussion/Conclusions Acculturation is multidimensional. Implications for Practice Care providers should examine acculturation as a bidimensional construct. PMID:23361579

Study design in medical research: part 2 of a series on the evaluation of scientific publications.

PubMed

Röhrig, Bernd; du Prel, Jean-Baptist; Blettner, Maria

2009-03-01

The scientific value and informativeness of a medical study are determined to a major extent by the study design. Errors in study design cannot be corrected afterwards. Various aspects of study design are discussed in this article. Six essential considerations in the planning and evaluation of medical research studies are presented and discussed in the light of selected scientific articles from the international literature as well as the authors' own scientific expertise with regard to study design. The six main considerations for study design are the question to be answered, the study population, the unit of analysis, the type of study, the measuring technique, and the calculation of sample size. This article is intended to give the reader guidance in evaluating the design of studies in medical research. This should enable the reader to categorize medical studies better and to assess their scientific quality more accurately.

What's in a Name? The Incorrect Use of Case Series as a Study Design Label in Studies Involving Dogs and Cats.

PubMed

Sargeant, J M; O'Connor, A M; Cullen, J N; Makielski, K M; Jones-Bitton, A

2017-07-01

Study design labels are used to identify relevant literature to address specific clinical and research questions and to aid in evaluating the evidentiary value of research. Evidence from the human healthcare literature indicates that the label "case series" may be used inconsistently and inappropriately. Our primary objective was to determine the proportion of studies in the canine and feline veterinary literature labeled as case series that actually corresponded to descriptive cohort studies, population-based cohort studies, or other study designs. Our secondary objective was to identify the proportion of case series in which potentially inappropriate inferential statements were made. Descriptive evaluation of published literature. One-hundred published studies (from 19 journals) labeled as case series. Studies were identified by a structured literature search, with random selection of 100 studies from the relevant citations. Two reviewers independently characterized each study, with disagreements resolved by consensus. Of the 100 studies, 16 were case series. The remaining studies were descriptive cohort studies (35), population-based cohort studies (36), or other observational or experimental study designs (13). Almost half (48.8%) of the case series or descriptive cohort studies, with no control group and no formal statistical analysis, included inferential statements about the efficacy of treatment or statistical significance of potential risk factors. Authors, peer-reviewers, and editors should carefully consider the design elements of a study to accurately identify and label the study design. Doing so will facilitate an understanding of the evidentiary value of the results. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Comparison of Estimates between Cohort and Case-Control Studies in Meta-Analyses of Therapeutic Interventions: A Meta-Epidemiological Study.

PubMed

Lanza, Amy; Ravaud, Philippe; Riveros, Carolina; Dechartres, Agnes

2016-01-01

Observational studies are increasingly being used for assessing therapeutic interventions. Case-control studies are generally considered to have greater risk of bias than cohort studies, but we lack evidence of differences in effect estimates between the 2 study types. We aimed to compare estimates between cohort and case-control studies in meta-analyses of observational studies of therapeutic interventions by using a meta-epidemiological study. We used a random sample of meta-analyses of therapeutic interventions published in 2013 that included both cohort and case-control studies assessing a binary outcome. For each meta-analysis, the ratio of estimates (RE) was calculated by comparing the estimate in case-control studies to that in cohort studies. Then, we used random-effects meta-analysis to estimate a combined RE across meta-analyses. An RE < 1 indicated that case-control studies yielded larger estimates than cohort studies. The final analysis included 23 meta-analyses: 138 cohort and 133 case-control studies. Treatment effect estimates did not significantly differ between case-control and cohort studies (combined RE 0.97 [95% CI 0.86-1.09]). Heterogeneity was low, with between-meta-analysis variance τ2 = 0.0049. Estimates did not differ between case-control and prospective or retrospective cohort studies (RE = 1.05 [95% CI 0.96-1.15] and RE = 0.99 [95% CI, 0.83-1.19], respectively). Sensitivity analysis of studies reporting adjusted estimates also revealed no significant difference (RE = 1.03 [95% CI 0.91-1.16]). Heterogeneity was also low for these analyses. We found no significant difference in treatment effect estimates between case-control and cohort studies assessing therapeutic interventions.

Environmental toxicants and autism spectrum disorders: a systematic review

PubMed Central

Rossignol, D A; Genuis, S J; Frye, R E

2014-01-01

Although the involvement of genetic abnormalities in autism spectrum disorders (ASD) is well-accepted, recent studies point to an equal contribution by environmental factors, particularly environmental toxicants. However, these toxicant-related studies in ASD have not been systematically reviewed to date. Therefore, we compiled publications investigating potential associations between environmental toxicants and ASD and arranged these publications into the following three categories: (a) studies examining estimated toxicant exposures in the environment during the preconceptional, gestational and early childhood periods; (b) studies investigating biomarkers of toxicants; and (c) studies examining potential genetic susceptibilities to toxicants. A literature search of nine electronic scientific databases through November 2013 was performed. In the first category examining ASD risk and estimated toxicant exposures in the environment, the majority of studies (34/37; 92%) reported an association. Most of these studies were retrospective case–control, ecological or prospective cohort studies, although a few had weaker study designs (for example, case reports or series). Toxicants implicated in ASD included pesticides, phthalates, polychlorinated biphenyls (PCBs), solvents, toxic waste sites, air pollutants and heavy metals, with the strongest evidence found for air pollutants and pesticides. Gestational exposure to methylmercury (through fish exposure, one study) and childhood exposure to pollutants in water supplies (two studies) were not found to be associated with ASD risk. In the second category of studies investigating biomarkers of toxicants and ASD, a large number was dedicated to examining heavy metals. Such studies demonstrated mixed findings, with only 19 of 40 (47%) case–control studies reporting higher concentrations of heavy metals in blood, urine, hair, brain or teeth of children with ASD compared with controls. Other biomarker studies reported that solvent, phthalate and pesticide levels were associated with ASD, whereas PCB studies were mixed. Seven studies reported a relationship between autism severity and heavy metal biomarkers, suggesting evidence of a dose–effect relationship. Overall, the evidence linking biomarkers of toxicants with ASD (the second category) was weaker compared with the evidence associating estimated exposures to toxicants in the environment and ASD risk (the first category) because many of the biomarker studies contained small sample sizes and the relationships between biomarkers and ASD were inconsistent across studies. Regarding the third category of studies investigating potential genetic susceptibilities to toxicants, 10 unique studies examined polymorphisms in genes associated with increased susceptibilities to toxicants, with 8 studies reporting that such polymorphisms were more common in ASD individuals (or their mothers, 1 study) compared with controls (one study examined multiple polymorphisms). Genes implicated in these studies included paraoxonase (PON1, three of five studies), glutathione S-transferase (GSTM1 and GSTP1, three of four studies), δ-aminolevulinic acid dehydratase (one study), SLC11A3 (one study) and the metal regulatory transcription factor 1 (one of two studies). Notably, many of the reviewed studies had significant limitations, including lack of replication, limited sample sizes, retrospective design, recall and publication biases, inadequate matching of cases and controls, and the use of nonstandard tools to diagnose ASD. The findings of this review suggest that the etiology of ASD may involve, at least in a subset of children, complex interactions between genetic factors and certain environmental toxicants that may act synergistically or in parallel during critical periods of neurodevelopment, in a manner that increases the likelihood of developing ASD. Because of the limitations of many of the reviewed studies, additional high-quality epidemiological studies concerning environmental toxicants and ASD are warranted to confirm and clarify many of these findings. PMID:24518398

Assessing the first wave of epidemiological studies of nanomaterial workers

NASA Astrophysics Data System (ADS)

Liou, Saou-Hsing; Tsai, Candace S. J.; Pelclova, Daniela; Schubauer-Berigan, Mary K.; Schulte, Paul A.

2015-10-01

The results of early animal studies of engineered nanomaterials (ENMs) and air pollution epidemiology suggest that it is important to assess the health of ENM workers. Initial epidemiological studies of workers' exposure to ENMs (<100 nm) are reviewed and characterized for their study designs, findings, and limitations. Of the 15 studies, 11 were cross-sectional, 4 were longitudinal (1 was both cross-sectional and longitudinal in design), and 1 was a descriptive pilot study. Generally, the studies used biologic markers as the dependent variables. All 11 cross-sectional studies showed a positive relationship between various biomarkers and ENM exposures. Three of the four longitudinal studies showed a negative relationship; the fourth showed positive findings after a 1-year follow-up. Each study considered exposure to ENMs as the independent variable. Exposure was assessed by mass concentration in 10 studies and by particle count in six studies. Six of them assessed both mass and particle concentrations. Some of the studies had limited exposure data because of inadequate exposure assessment. Generally, exposure levels were not very high in comparison to those in human inhalation chamber studies, but there were some exceptions. Most studies involved a small sample size, from 2 to 258 exposed workers. These studies represent the first wave of epidemiological studies of ENM workers. They are limited by small numbers of participants, inconsistent (and in some cases inadequate) exposure assessments, generally low exposures, and short intervals between exposure and effect. Still, these studies are a foundation for future work; they provide insight into where ENM workers are experiencing potentially adverse effects that might be related to ENM exposures.

Alcohol Intake and Risk of Thyroid Cancer: A Meta-Analysis of Observational Studies.

PubMed

Hong, Seung-Hee; Myung, Seung-Kwon; Kim, Hyeon Suk

2017-04-01

The purpose of this study was to assess whether alcohol intake is associated with the risk of thyroid cancer by a meta-analysis of observational studies. We searched PubMed and EMBASE in June of 2015 to locate eligible studies. We included observational studies such as cross-sectional studies, case-control studies, and cohort studies reporting odd ratios (ORs) or relative risk (RRs) with 95% confidence intervals (CIs). We included 33 observational studies with two cross-sectional studies, 20 case-controls studies, and 11 cohort studies, which involved a total of 7,725 thyroid cancer patients and 3,113,679 participants without thyroid cancer in the final analysis. In the fixed-effect model meta-analysis of all 33 studies, we found that alcohol intake was consistently associated with a decreased risk of thyroid cancer (OR or RR, 0.74; 95% CI, 0.67 to 0.83; I 2 =38.6%). In the subgroup meta-analysis by type of study, alcohol intake also decreased the risk of thyroid cancer in both case-control studies (OR, 0.77; 95% CI, 0.65 to 0.92; I 2 =29.5%; n=20) and cohort studies (RR, 0.70; 95% CI, 0.60 to 0.82; I 2 =0%; n=11). Moreover, subgroup meta-analyses by type of thyroid cancer, gender, amount of alcohol consumed, and methodological quality of study showed that alcohol intake was significantly associated with a decreased risk of thyroid cancer. The current meta-analysis of observational studies found that, unlike most of other types of cancer, alcohol intake decreased the risk of thyroid cancer.

The Family-Study Interface and Academic Outcomes: Testing a Structural Model

ERIC Educational Resources Information Center

Meeuwisse, Marieke; Born, Marise Ph.; Severiens, Sabine E.

2011-01-01

Expanding on family-work and work-study models, this article investigated a model for family-study conflict and family-study facilitation. The focus of the study was the relationship of family-study conflict and family-study facilitation with students' effortful behaviors and academic performance among a sample of university students (N = 1,656).…

Meta-Travel: A Critical Inquiry into a China Study Tour

ERIC Educational Resources Information Center

Riggan, Jennifer; Gwak, Sonya; Lesnick, Joy; Jackson, Kara; Olitsky, Stacey

2011-01-01

Short-term study tours are among the fastest growing of study abroad experiences and serve the largest percentage of students choosing to study abroad. Fifty-six percent of students studying abroad go on short-term study trips lasting anywhere from two to eight weeks. These trips have the advantage of being able to provide study travel experiences…

40 CFR 152.94 - Citation of a public literature study or study generated at government expense.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Citation of a public literature study... public literature study or study generated at government expense. (a) An applicant may demonstrate... study from the public literature. (2) A valid study generated by, or at the expense of, any government...

Increasing Asian American women's research participation: the Asian grocery store-based cancer education program.

PubMed

Sadler, Georgia Robins; Ko, Celine M; Takahashi, Mitsuko; Ching, Christy R; Lee, Irene; Chuang, Gin C; Lee, Kathy K

2010-07-01

Research study participants with diverse characteristics produce the most generalizable outcomes, but recruiting heterogeneous samples is difficult. This pilot study tests whether Asian women (N=1079) with diverse language proficiencies, who were personally recruited to one study by a linguistically and culturally aligned recruiter, would enroll in another study with a single mailed invitation in English. The 134 participants in the second study represented 17.2% of those 779 women who had completed both baseline and follow-up surveys in the original study, making this characteristic the best predictor of future study participation. Of the 303 women in the first study who said they would be willing to participate in future studies, 17% (51) participated in the second study. Of the 733 who said they would not be willing to participate in future studies, 11% (83) participated. However, given the larger size of this group, researchers may recruit a greater absolute number of participants from it. While this rate of participation was less than the 25% rate achieved in the first study, the second study's single, mailed English language invitation was likely a barrier to participation. Securing IRB-approval to invite prior study participants from traditionally underrepresented communities to a new study is a strategy investigators can use to increase the diversity of their samples. Further research is warranted to determine whether Asian women who have participated in one study might also become effective recruiters for future studies.

The scale of the evidence base on the health effects of conventional yogurt consumption: findings of a scoping review

PubMed Central

Glanville, Julie M.; Brown, Sam; Shamir, Raanan; Szajewska, Hania; Eales, Jacqualyn F.

2015-01-01

Background: The health effects of conventional yogurt have been investigated for over a century; however, few systematic reviews have been conducted to assess the extent of the health benefits of yogurt. Objective: The aim of this scoping review was to assess the volume of available evidence on the health effects of conventional yogurt. Methods: The review was guided by a protocol agreed a priori and informed by an extensive literature search conducted in November 2013. Randomized controlled trials were selected and categorized according to the eligibility criteria established in the protocol. Results: 213 studies were identified as relevant to the scoping question. The number of eligible studies identified for each outcome were: bone health (14 studies), weight management and nutrition related health outcomes (81 studies), metabolic health (6 studies); cardiovascular health (57 studies); gastrointestinal health (24 studies); cancer (39 studies); diabetes (13 studies), Parkinson's disease risk (3 studies), all-cause mortality (3 studies), skin complaints (3 studies), respiratory complaints (3 studies), joint pain/function (2 studies); the remaining 8 studies reported a variety of other outcomes. For studies of a similar design and which assessed the same outcomes in similar population groups, we report the potential for the combining of data across studies in systematic reviews. Conclusions: This scoping review has revealed the extensive evidence base for many outcomes which could be the focus of systematic reviews exploring the health effects of conventional yogurt consumption. PMID:26578956

How do veterinary students' motivation and study practices relate to academic success?

PubMed

Mikkonen, Johanna; Ruohoniemi, Mirja

2011-01-01

The aim of the present study was to explore the factors associated with veterinary students' study success. All veterinary students who began their studies at the University of Helsinki in 2005 participated in this qualitative longitudinal study (N=52). The data consisted of assignments that the students completed at the beginning of their studies and again after three years of studying. The focus was on differences in motivation and study practices as well as possible changes in these over the three-year period. The students were divided into three groups according to their study success (grade point average and study progress). These groups were compared according to group-level differences in the categorized data. The most successful students already described themselves using more positive words than other students at the beginning of their veterinary studies. In addition, they seemed more adaptive in relation to the study's demands. However, there were drops in both the most and least successful students' motivation during their studies. The findings suggest that it is possible to predict forthcoming study problems by analyzing students' study practices and their own descriptions of themselves as learners. In addition, the results show that veterinary students' high motivation cannot be taken for granted. The comparative and longitudinal perspective of the present study can be useful in the development of curricula and in student support.

Heterogeneity in application, design, and analysis characteristics was found for controlled before-after and interrupted time series studies included in Cochrane reviews.

PubMed

Polus, Stephanie; Pieper, Dawid; Burns, Jacob; Fretheim, Atle; Ramsay, Craig; Higgins, Julian P T; Mathes, Tim; Pfadenhauer, Lisa M; Rehfuess, Eva A

2017-11-01

The aim of the study was to examine the application, design, and analysis characteristics of controlled before-after (CBA) and interrupted time series (ITS) studies and their use in Cochrane reviews. We searched the Cochrane library for reviews including these study designs from May 2012 to March 2015 and purposively selected, where available, two reviews each across 10 prespecified intervention types. We randomly selected two CBA and two ITS studies from each review. Two researchers independently extracted information from the studies and the respective reviews. Sixty-nine reviews considered CBA and ITS studies for inclusion. We analyzed 21 CBA and 16 ITS studies from 11 to 8 reviews, respectively. Cochrane reviews inconsistently defined and labeled CBA and ITS studies. Many studies did not meet the Cochrane definition or the minimum criteria provided by Cochrane Effective Practice and Organisation of Care. The studies present a heterogeneous set of study features and applied a large variety of analyses. While CBA and ITS studies represent important study designs to evaluate the effects of interventions, especially on a population or organizational level, unclear study design features challenge unequivocal classification and appropriate use. We discuss options for more specific definitions and explicit criteria for CBA and ITS studies. Copyright © 2017 Elsevier Inc. All rights reserved.

Poor relation between biomechanical and clinical studies for the proximal femoral locking compression plate

PubMed Central

Viberg, Bjarke; Rasmussen, Katrine M V; Overgaard, Søren; Rogmark, Cecilia

2017-01-01

Background and purpose The proximal femur locking compression plate (PF-LCP) is a new concept in the treatment of hip fractures. When releasing new implants onto the market, biomechanical studies are conducted to evaluate performance of the implant. We investigated the relation between biomechanical and clinical studies on PF-LCP. Methods A systematic literature search of relevant biomechanical and clinical studies was conducted in PubMed on December 1, 2015. 7 biomechanical studies and 15 clinical studies were included. Results Even though the biomechanical studies showed equivalent or higher failure loads for femoral neck fracture, the clinical results were far worse, with a 37% complication rate. There were no biomechanical studies on pertrochanteric fractures. Biomechanical studies on subtrochanteric fractures showed that PF-LCP had a lower failure load than with proximal femoral nail, but higher than with angled blade plate. 4 clinical studies had complication rates less than 8% and 9 studies had complication rates between 15% and 53%. Interpretation There was no clear relation between biomechanical and clinical studies. Biomechanical studies are generally inherently different from clinical studies, as they examine the best possible theoretical use of the implant without considering the long-term outcome in a clinical setting. Properly designed clinical studies are mandatory when introducing new implants, and they cannot be replaced by biomechanical studies. PMID:28287002

A tutorial on pilot studies: the what, why and how

PubMed Central

2010-01-01

Pilot studies for phase III trials - which are comparative randomized trials designed to provide preliminary evidence on the clinical efficacy of a drug or intervention - are routinely performed in many clinical areas. Also commonly know as "feasibility" or "vanguard" studies, they are designed to assess the safety of treatment or interventions; to assess recruitment potential; to assess the feasibility of international collaboration or coordination for multicentre trials; to increase clinical experience with the study medication or intervention for the phase III trials. They are the best way to assess feasibility of a large, expensive full-scale study, and in fact are an almost essential pre-requisite. Conducting a pilot prior to the main study can enhance the likelihood of success of the main study and potentially help to avoid doomed main studies. The objective of this paper is to provide a detailed examination of the key aspects of pilot studies for phase III trials including: 1) the general reasons for conducting a pilot study; 2) the relationships between pilot studies, proof-of-concept studies, and adaptive designs; 3) the challenges of and misconceptions about pilot studies; 4) the criteria for evaluating the success of a pilot study; 5) frequently asked questions about pilot studies; 7) some ethical aspects related to pilot studies; and 8) some suggestions on how to report the results of pilot investigations using the CONSORT format. PMID:20053272

Integrating Human Factors into Crew Exploration Vehicle (CEV) Design

NASA Technical Reports Server (NTRS)

Whitmore, Mihriban; Holden, Kritina; Baggerman, Susan; Campbell, Paul

2007-01-01

The purpose of this design process is to apply Human Engineering (HE) requirements and guidelines to hardware/software and to provide HE design, analysis and evaluation of crew interfaces. The topics include: 1) Background/Purpose; 2) HE Activities; 3) CASE STUDY: Net Habitable Volume (NHV) Study; 4) CASE STUDY: Human Modeling Approach; 5) CASE STUDY: Human Modeling Results; 6) CASE STUDY: Human Modeling Conclusions; 7) CASE STUDY: Human-in-the-Loop Evaluation Approach; 8) CASE STUDY: Unsuited Evaluation Results; 9) CASE STUDY: Suited Evaluation Results; 10) CASE STUDY: Human-in-the-Loop Evaluation Conclusions; 11) Near-Term Plan; and 12) In Conclusion

Mineral Resources of the Morey and Fandango Wilderness Study Areas, Nye County, Nevada

USGS Publications Warehouse

John, David A.; Nash, J. Thomas; Plouff, Donald; McDonnell, John R.

1987-01-01

The Morey (NV-060-191) and Fandango (NV-060-190) Wilderness Study Areas are located in the northern Hot Creek Range about 25 mi north of Warm Springs, Nev. At the request of the Bureau of Land Management, 46,300 acres of the Morey and Fandango Wilderness Study Areas were studied. In this report, the area studied is referred to as 'the wilderness study area', or simply 'the study area'. Geologic, geochemical, geophysical, and mineral surveys were conducted by the USGS and the USBM in 1984 to appraise the identified mineral resources and to assess the mineral resource potential of the study areas. These studies indicate that there are small identified resources of zinc, lead, and silver at the Lead Pipe property in the Fandango Wilderness Study Area, several areas of high potential for the occurrence of gold resources in the Fandango study area, small areas of low and moderate potential for the occurrence of silver, lead, and zinc resources in the Fandango study area, areas of moderate and high potential for the occurrence of silver, lead, and zinc resources in the Morey study area, and an area of low potential for copper, molybdenum, and tin in the Morey study area. Both study areas have low resource potential for petroleum, natural gas, uranium, and geothermal energy.

Qualitative "trial-sibling" studies and "unrelated" qualitative studies contributed to complex intervention reviews.

PubMed

Noyes, Jane; Hendry, Margaret; Lewin, Simon; Glenton, Claire; Chandler, Jackie; Rashidian, Arash

2016-06-01

To compare the contribution of "trial-sibling" and "unrelated" qualitative studies in complex intervention reviews. Researchers are using qualitative "trial-sibling" studies undertaken alongside trials to provide explanations to understand complex interventions. In the absence of qualitative "trial-sibling" studies, it is not known if qualitative studies "unrelated" to trials are helpful. Trials, "trial-sibling," and "unrelated" qualitative studies looking at three health system interventions were identified. We looked for similarities and differences between the two types of qualitative studies, such as participants, intervention delivery, context, study quality and reporting, and contribution to understanding trial results. Reporting was generally poor in both qualitative study types. We detected no substantial differences in participant characteristics. Interventions in qualitative "trial-sibling" studies were delivered using standardized protocols, whereas interventions in "unrelated" qualitative studies were delivered in routine care. Qualitative "trial-sibling" studies alone provided insufficient data to develop meaningful transferrable explanations beyond the trial context, and their limited focus on immediate implementation did not address all phenomena of interest. Together, "trial-sibling" and "unrelated" qualitative studies provided larger, richer data sets across contexts to better understand the phenomena of interest. Findings support inclusion of "trial-sibling" and "unrelated" qualitative studies to explore complexity in complex intervention reviews. Copyright © 2016 Elsevier Inc. All rights reserved.

Activity and participation, quality of life and user satisfaction outcomes of environmental control systems and smart home technology: a systematic review.

PubMed

Brandt, Ase; Samuelsson, Kersti; Töytäri, Outi; Salminen, Anna-Liisa

2011-01-01

To examine activity and participation, quality of life, and user satisfaction outcomes of environmental control systems (ECSs) and smart home technology (SHT) interventions for persons with impairments. A systematic review. Seventeen databases, three conference proceedings, and two journals were searched without language or study design restrictions covering the period January 1993 - June 2009. Reviewers selected studies, extracted data, and assessed the methodological quality independently. Of 1739 studies identified, five effect studies and six descriptive studies were included. One study was on SHT and the remainder on ECS; functionalities were overlapping. The studies varied in most aspects, and no synthesis could be drawn. However, ECS/SHT tended to increase study participants' independence, instrumental activities of daily living, socialising, and quality of life. Two studies showed high user satisfaction. The level of evidence was regarded as low, mainly due to small study sizes, lacking confounder control, and a majority of descriptive studies. Due to few and small studies and study diversity, it was not possible to determine whether ECS/SHT have positive outcomes for persons with impairment, even though the technologies seem to be promising. High quality outcomes studies such as randomised controlled trials, when feasible, and large longitudinal multi-centre studies are required.

Reporting of methodological features in observational studies of pre-harvest food safety.

PubMed

Sargeant, Jan M; O'Connor, Annette M; Renter, David G; Kelton, David F; Snedeker, Kate; Wisener, Lee V; Leonard, Erin K; Guthrie, Alessia D; Faires, Meredith

2011-02-01

Observational studies in pre-harvest food safety may be useful for identifying risk factors and for evaluating potential mitigation strategies to reduce foodborne pathogens. However, there are no structured reporting guidelines for these types of study designs in livestock species. Our objective was to evaluate the reporting of observational studies in the pre-harvest food safety literature using guidelines modified from the human healthcare literature. We identified 100 pre-harvest food safety studies published between 1999 and 2009. Each study was evaluated independently by two reviewers using a structured checklist. Of the 38 studies that explicitly stated the observational study design, 27 were described as cross-sectional studies, eight as case-control studies, and three as cohort studies. Study features reported in over 75% of the selected studies included: description of the geographic location of the studies, definitions and sources of data for outcomes, organizational level and source of data for independent variables, description of statistical methods and results, number of herds enrolled in the study and included in the analysis, and sources of study funding. However, other features were not consistently reported, including details related to eligibility criteria for groups (such as barn, room, or pen) and individuals, numbers of groups and individuals included in various stages of the study, identification of primary outcomes, the distinction between putative risk factors and confounding variables, the identification of a primary exposure variable, the referent level for evaluation of categorical variable associations, methods of controlling confounding variables and missing variables, model fit, details of subset analysis, demographic information at the sampling unit level, and generalizability of the study results. Improvement in reporting of observational studies of pre-harvest food safety will aid research readers and reviewers in interpreting and evaluating the results of such studies. Copyright © 2010 Elsevier B.V. All rights reserved.

78 FR 66945 - Proposed Collection; 60-Day Comment request: Gulf Long-Term Follow-Up Study (GuLF STUDY)

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-07

... Comment request: Gulf Long-Term Follow-Up Study (GuLF STUDY) Summary: In compliance with the requirement... days of the date of this publication. Proposed Collection: Gulf Long-Term Follow-Up Study (GuLF STUDY... GuLF STUDY is to investigate potential short- and long-term health effects associated with oil spill...

Assessment of the Basic Law Lesson Consistent with the Opinions of Social Studies Pre-Service Teachers

ERIC Educational Resources Information Center

Haçat, Sibel Oguz

2018-01-01

The aim of the present study is to identify the approach of social studies pre-service teachers to legal topics in the "Basic Law" lesson within the Social Studies Teaching Bachelor's Degree Program. A case study based on qualitative research methods was employed. The study group consisted of 57 social studies pre-service teachers. Data…

Alabama Course of Study: Social Studies K-12. Bulletin 1980, No. 22. Revised.

ERIC Educational Resources Information Center

Alabama State Dept. of Education, Montgomery.

This guide presents in four sections a course of study in social studies for use in Alabama for grades K-12. Section one includes a rationale for teaching social studies; a listing of management, methods, and content characteristics of a good social studies program; and an extensive list of social studies objectives. Some objectives of the program…

Responses of Study Abroad Students in Australia to Experience-Based Pedagogy in Sport Studies

ERIC Educational Resources Information Center

Light, Richard; Georgakis, Steve

2008-01-01

This paper contributes to research on the scholarship of teaching in the physical education/sport studies fields by examining the responses of study abroad students from overseas studying in Australia to a unit of study in sport studies that placed the interpretation of experience as the centre of the learning process. It draws on research…

Why don't girls choose technological studies? Adolescents' stereotypes and attitudes towards studies related to medicine or engineering.

PubMed

López-Sáez, Mercedes; Puertas, Susana; Sáinz, Milagros

2011-05-01

Gender differences in choice of studies emerge already in adolescence. Two studies with adolescents are presented, the goal of which is to explore the influence of gender by assessing males and females who choose studies related to Medicine or Engineering. Study 1, correlational (N = 330, mean age 15.9, 56.7% girls), shows that girls who choose technology are more poorly appraised than girls who choose other studies. Study 2 (N = 130; mean age 16.77, 56.2% girls), experimental, measures implicit attitudes (using the IAT) towards males and females from Medicine and Engineering. Implicit attitudes are more favorable towards women if they are studying Medicine and towards men if they study Engineering. The results are analyzed with relation to the percentages of boys and girls in the different fields of study.

Evaluation of streams in selected communities for the application of limited-detail study methods for flood-insurance studies

USGS Publications Warehouse

Cobb, Ernest D.

1986-01-01

The U.S. Geological Survey evaluated 2,349 communities in 1984 for the application of limited-detail flood-insurance study methods, that is, methods with a reduced effort and cost compared to the detailed studies. Limited-detail study methods were found to be appropriate for 1,705 communities, while detailed studies were appropriate for 62 communities and no studies were appropriate for 582 communities. The total length of streams for which limited-detail studies are recommended is 9 ,327 miles with a corresponding cost of $23,007,000. This results in average estimated costs for conducting limited-detail studies of $2,500 per mile of studied stream length. The purpose of the report is to document the limited-detail study methods and the results of the evaluation. (USGS)

Human Health Exposure Assessment for Rocky Mountain Arsenal. Volume 8. Response to Comments on the Draft Exposure Assessment Version 4.1

DTIC Science & Technology

1990-09-01

ASSESSMENT (INCLUDES ARMY AND SHELL TOXICITY PROFILES). VOL. 41V - PPLV METHODOLOGY. VOL. V - PPLV CALCULATIONS. VOL. VI - STUDY AREA EXPOSURE ANALYSIS (A...INTRODUCTION, B WESTERN STUDY AREA, C SOUTHERN STUDY AREA, D NORTHERN CENTRAL STUDY AREA, E CENTRAL STUDY AREA, F EASTERN STUDY AREA, G SOUTH PLANTS... STUDY AREA, AND H NORTH PLANTS STUDY AREA. VOL. VII - SUMMARY EXPOSURE ASSESSMENT. VOL. VIII - 14. SUBJECT TERMS 15. NUMBER OF PAGES PPLV, LAND USE

Adjusting to death: the effects of mortality salience and self-esteem on psychological well-being, growth motivation, and maladaptive behavior.

PubMed

Routledge, Clay; Ostafin, Brian; Juhl, Jacob; Sedikides, Constantine; Cathey, Christie; Liao, Jiangqun

2010-12-01

This research builds on terror management theory to examine the relationships among self-esteem, death cognition, and psychological adjustment. Self-esteem was measured (Studies 1-2, 4-8) or manipulated (Study 3), and thoughts of death were manipulated (Studies 1-3, 5-8) or measured (Study 4). Subsequently, satisfaction with life (Study 1), subjective vitality (Study 2), meaning in life (Studies 3-5), positive and negative affect (Studies 1, 4, 5), exploration (Study 6), state anxiety (Study 7), and social avoidance (Study 8) were assessed. Death-related cognition (a) decreased satisfaction with life, subjective vitality, meaning in life, and exploration; (b) increased negative affect and state anxiety; and (c) exacerbated social avoidance for individuals with low self-esteem but not for those with high self-esteem. These effects occurred only when death thoughts were outside of focal attention. Parallel effects were found in American (Studies 1-4, 6-8) and Chinese (Study 5) samples. PsycINFO Database Record (c) 2010 APA, all rights reserved.

A Systematic Review of Interventions to Change Staff Care Practices in Order to Improve Resident Outcomes in Nursing Homes

PubMed Central

Low, Lee-Fay; Fletcher, Jennifer; Goodenough, Belinda; Jeon, Yun-Hee; Etherton-Beer, Christopher; MacAndrew, Margaret; Beattie, Elizabeth

2015-01-01

Background We systematically reviewed interventions that attempted to change staff practice to improve long-term care resident outcomes. Methods Studies met criteria if they used a control group, included 6 or more nursing home units and quantitatively assessed staff behavior or resident outcomes. Intervention components were coded as including education material, training, audit and feedback, monitoring, champions, team meetings, policy or procedures and organizational restructure. Results Sixty-three unique studies were broadly grouped according to clinical domain—oral health (3 studies), hygiene and infection control (3 studies), nutrition (2 studies), nursing home acquired pneumonia (2 studies), depression (2 studies) appropriate prescribing (7 studies), reduction of physical restraints (3 studies), management of behavioral and psychological symptoms of dementia (6 studies), falls reduction and prevention (11 studies), quality improvement (9 studies), philosophy of care (10 studies) and other (5 studies). No single intervention component, combination of, or increased number of components was associated with greater likelihood of positive outcomes. Studies with positive outcomes for residents also tended to change staff behavior, however changing staff behavior did not necessarily improve resident outcomes. Studies targeting specific care tasks (e.g. oral care, physical restraints) were more likely to produce positive outcomes than those requiring global practice changes (e.g. care philosophy). Studies using intervention theories were more likely to be successful. Program logic was rarely articulated, so it was often unclear whether there was a coherent connection between the intervention components and measured outcomes. Many studies reported barriers relating to staff (e.g. turnover, high workload, attitudes) or organizational factors (e.g. funding, resources, logistics). Conclusion Changing staff practice in nursing homes is possible but complex. Interventionists should consider barriers and feasibility of program components to impact on each intended outcome. PMID:26559675

Empirical evidence of the importance of comparative studies of diagnostic test accuracy.

PubMed

Takwoingi, Yemisi; Leeflang, Mariska M G; Deeks, Jonathan J

2013-04-02

Systematic reviews that "compare" the accuracy of 2 or more tests often include different sets of studies for each test. To investigate the availability of direct comparative studies of test accuracy and to assess whether summary estimates of accuracy differ between meta-analyses of noncomparative and comparative studies. Systematic reviews in any language from the Database of Abstracts of Reviews of Effects and the Cochrane Database of Systematic Reviews from 1994 to October 2012. 1 of 2 assessors selected reviews that evaluated at least 2 tests and identified meta-analyses that included both noncomparative studies and comparative studies. 1 of 3 assessors extracted data about review and study characteristics and test performance. 248 reviews compared test accuracy; of the 6915 studies, 2113 (31%) were comparative. Thirty-six reviews (with 52 meta-analyses) had adequate studies to compare results of noncomparative and comparative studies by using a hierarchical summary receiver-operating characteristic meta-regression model for each test comparison. In 10 meta-analyses, noncomparative studies ranked tests in the opposite order of comparative studies. A total of 25 meta-analyses showed more than a 2-fold discrepancy in the relative diagnostic odds ratio between noncomparative and comparative studies. Differences in accuracy estimates between noncomparative and comparative studies were greater than expected by chance (P < 0.001). A paucity of comparative studies limited exploration of direction in bias. Evidence derived from noncomparative studies often differs from that derived from comparative studies. Robustly designed studies in which all patients receive all tests or are randomly assigned to receive one or other of the tests should be more routinely undertaken and are preferred for evidence to guide test selection. National Institute for Health Research (United Kingdom).

Pending studies at hospital discharge: a pre-post analysis of an electronic medical record tool to improve communication at hospital discharge.

PubMed

Kantor, Molly A; Evans, Kambria H; Shieh, Lisa

2015-03-01

Achieving safe transitions of care at hospital discharge requires accurate and timely communication. Both the presence of and follow-up plan for diagnostic studies that are pending at hospital discharge are expected to be accurately conveyed during these transitions, but this remains a challenge. To determine the prevalence, characteristics, and communication of studies pending at hospital discharge before and after the implementation of an electronic medical record (EMR) tool that automatically generates a list of pending studies. Pre-post analysis. 260 consecutive patients discharged from inpatient general medicine services from July to August 2013. Development of an EMR-based tool that automatically generates a list of studies pending at discharge. The main outcomes were prevalence and characteristics of pending studies and communication of studies pending at hospital discharge. We also surveyed internal medicine house staff on their attitudes about communication of pending studies. Pre-intervention, 70% of patients had at least one pending study at discharge, but only 18% of these were communicated in the discharge summary. Most studies were microbiology cultures (68%), laboratory studies (16%), or microbiology serologies (10%). The majority of study results were ultimately normal (83%), but 9% were newly abnormal. Post-intervention, communication of studies pending increased to 43% (p < 0.001). Most patients are discharged from the hospital with pending studies, but in usual practice, the presence of these studies has rarely been communicated to outpatient providers in the discharge summary. Communication significantly increased with the implementation of an EMR-based tool that automatically generated a list of pending studies from the EMR and allowed users to import this list into the discharge summary. This is the first study to our knowledge to introduce an automated EMR-based tool to communicate pending studies.

Alcohol Intake and Risk of Thyroid Cancer: A Meta-Analysis of Observational Studies

PubMed Central

Hong, Seung-Hee; Myung, Seung-Kwon; Kim, Hyeon Suk

2017-01-01

Purpose The purpose of this study was to assess whether alcohol intake is associated with the risk of thyroid cancer by a meta-analysis of observational studies. Materials and Methods We searched PubMed and EMBASE in June of 2015 to locate eligible studies. We included observational studies such as cross-sectional studies, case-control studies, and cohort studies reporting odd ratios (ORs) or relative risk (RRs) with 95% confidence intervals (CIs). Results We included 33 observational studies with two cross-sectional studies, 20 case-controls studies, and 11 cohort studies, which involved a total of 7,725 thyroid cancer patients and 3,113,679 participants without thyroid cancer in the final analysis. In the fixed-effect model meta-analysis of all 33 studies, we found that alcohol intake was consistently associated with a decreased risk of thyroid cancer (OR or RR, 0.74; 95% CI, 0.67 to 0.83; I2=38.6%). In the subgroup meta-analysis by type of study, alcohol intake also decreased the risk of thyroid cancer in both case-control studies (OR, 0.77; 95% CI, 0.65 to 0.92; I2=29.5%; n=20) and cohort studies (RR, 0.70; 95% CI, 0.60 to 0.82; I2=0%; n=11). Moreover, subgroup meta-analyses by type of thyroid cancer, gender, amount of alcohol consumed, and methodological quality of study showed that alcohol intake was significantly associated with a decreased risk of thyroid cancer. Conclusion The current meta-analysis of observational studies found that, unlike most of other types of cancer, alcohol intake decreased the risk of thyroid cancer. PMID:27456949

Endogenous Opioid Antagonism in Physiological Experimental Pain Models: A Systematic Review

PubMed Central

Werner, Mads U.; Pereira, Manuel P.; Andersen, Lars Peter H.; Dahl, Jørgen B.

2015-01-01

Opioid antagonists are pharmacological tools applied as an indirect measure to detect activation of the endogenous opioid system (EOS) in experimental pain models. The objective of this systematic review was to examine the effect of mu-opioid-receptor (MOR) antagonists in placebo-controlled, double-blind studies using ʻinhibitoryʼ or ʻsensitizingʼ, physiological test paradigms in healthy human subjects. The databases PubMed and Embase were searched according to predefined criteria. Out of a total of 2,142 records, 63 studies (1,477 subjects [male/female ratio = 1.5]) were considered relevant. Twenty-five studies utilized ʻinhibitoryʼ test paradigms (ITP) and 38 studies utilized ʻsensitizingʼ test paradigms (STP). The ITP-studies were characterized as conditioning modulation models (22 studies) and repetitive transcranial magnetic stimulation models (rTMS; 3 studies), and, the STP-studies as secondary hyperalgesia models (6 studies), ʻpainʼ models (25 studies), summation models (2 studies), nociceptive reflex models (3 studies) and miscellaneous models (2 studies). A consistent reversal of analgesia by a MOR-antagonist was demonstrated in 10 of the 25 ITP-studies, including stress-induced analgesia and rTMS. In the remaining 14 conditioning modulation studies either absence of effects or ambiguous effects by MOR-antagonists, were observed. In the STP-studies, no effect of the opioid-blockade could be demonstrated in 5 out of 6 secondary hyperalgesia studies. The direction of MOR-antagonist dependent effects upon pain ratings, threshold assessments and somatosensory evoked potentials (SSEP), did not appear consistent in 28 out of 32 ʻpainʼ model studies. In conclusion, only in 2 experimental human pain models, i.e., stress-induced analgesia and rTMS, administration of MOR-antagonist demonstrated a consistent effect, presumably mediated by an EOS-dependent mechanisms of analgesia and hyperalgesia. PMID:26029906

The Use of Social Media in Recruitment for Medical Research Studies: A Scoping Review.

PubMed

Topolovec-Vranic, Jane; Natarajan, Karthik

2016-11-07

Recruiting an adequate number of participants into medical research studies is challenging for many researchers. Over the past 10 years, the use of social media websites has increased in the general population. Consequently, social media websites are a new, powerful method for recruiting participants into such studies. The objective was to answer the following questions: (1) Is the use of social media more effective at research participant recruitment than traditional methods? (2) Does social media recruit a sample of research participants comparable to that recruited via other methods? (3) Is social media more cost-effective at research participant recruitment than traditional methods? Using the MEDLINE, PsycINFO, and EMBASE databases, all medical research studies that used social media and at least one other method for recruitment were identified. These studies were then categorized as either interventional studies or observational studies. For each study, the effectiveness of recruitment, demographic characteristics of the participants, and cost-effectiveness of recruitment using social media were evaluated and compared with that of the other methods used. The social media sites used in recruitment were identified, and if a study stated that the target population was "difficult to reach" as identified by the authors of the study, this was noted. Out of 30 studies, 12 found social media to be the most effective recruitment method, 15 did not, and 3 found social media to be equally effective as another recruitment method. Of the 12 studies that found social media to be the best recruitment method, 8 were observational studies while 4 were interventional studies. Of the 15 studies that did not find social media to be the best recruitment method, 7 were interventional studies while 8 were observational studies. In total, 8 studies stated that the target population was "hard-to-reach," and 6 of these studies found social media to be the most effective recruitment method. Out of 14 studies that reported demographic data for participants, 2 studies found that social media recruited a sample comparable to that recruited via traditional methods and 12 did not. Out of 13 studies that reported cost-effectiveness, 5 studies found social media to be the most cost-effective recruitment method, 7 did not, and 1 study found social media equally cost-effective as compared with other methods. Only 12 studies out of 30 found social media to be the most effective recruitment method. There is evidence that social media can be the best recruitment method for hard-to-reach populations and observational studies. With only 30 studies having compared recruitment through social media with other methods, more studies need to be done that report the effectiveness of recruitment for each strategy, demographics of participants recruited, and cost-effectiveness of each method. ©Jane Topolovec-Vranic, Karthik Natarajan. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 07.11.2016.

The Use of Social Media in Recruitment for Medical Research Studies: A Scoping Review

PubMed Central

2016-01-01

Background Recruiting an adequate number of participants into medical research studies is challenging for many researchers. Over the past 10 years, the use of social media websites has increased in the general population. Consequently, social media websites are a new, powerful method for recruiting participants into such studies. Objective The objective was to answer the following questions: (1) Is the use of social media more effective at research participant recruitment than traditional methods? (2) Does social media recruit a sample of research participants comparable to that recruited via other methods? (3) Is social media more cost-effective at research participant recruitment than traditional methods? Methods Using the MEDLINE, PsycINFO, and EMBASE databases, all medical research studies that used social media and at least one other method for recruitment were identified. These studies were then categorized as either interventional studies or observational studies. For each study, the effectiveness of recruitment, demographic characteristics of the participants, and cost-effectiveness of recruitment using social media were evaluated and compared with that of the other methods used. The social media sites used in recruitment were identified, and if a study stated that the target population was “difficult to reach” as identified by the authors of the study, this was noted. Results Out of 30 studies, 12 found social media to be the most effective recruitment method, 15 did not, and 3 found social media to be equally effective as another recruitment method. Of the 12 studies that found social media to be the best recruitment method, 8 were observational studies while 4 were interventional studies. Of the 15 studies that did not find social media to be the best recruitment method, 7 were interventional studies while 8 were observational studies. In total, 8 studies stated that the target population was “hard-to-reach,” and 6 of these studies found social media to be the most effective recruitment method. Out of 14 studies that reported demographic data for participants, 2 studies found that social media recruited a sample comparable to that recruited via traditional methods and 12 did not. Out of 13 studies that reported cost-effectiveness, 5 studies found social media to be the most cost-effective recruitment method, 7 did not, and 1 study found social media equally cost-effective as compared with other methods. Conclusions Only 12 studies out of 30 found social media to be the most effective recruitment method. There is evidence that social media can be the best recruitment method for hard-to-reach populations and observational studies. With only 30 studies having compared recruitment through social media with other methods, more studies need to be done that report the effectiveness of recruitment for each strategy, demographics of participants recruited, and cost-effectiveness of each method. PMID:27821383

The case-control design in veterinary sciences: A survey.

PubMed

Cullen, Jonah N; Sargeant, Jan M; Makielski, Kelly M; O'Connor, Annette M

2016-11-01

The case-control study design is deceptively simple. However, many design considerations influence the estimated effect measure. An investigation of case-control studies in the human health literature suggested that some of these considerations are not described in reports of case-control studies. Our hypothesis was that the majority of veterinary studies labeled as case-controls would be incident density designs, and many would not interpret the effect measure obtained from those studies as the rate ratio rather than the odds ratio. Reference databases were searched for author-designated case-control studies. A survey of 100 randomly selected studies was conducted to examine the different design options described and estimated effect measures. Of the 100 author-identified case-control studies, 83 assessed an exposure-outcome association and, of those, only 54 (65.1%) sampled the study population based on an outcome and would thus be considered case-control designs. Twelve studies were incidence density designs but none used this terminology. Of the studies that reported an odds ratio as the effect measure, none reported on additional considerations that would have enabled a more interpretable result. This survey indicated many case-control-labeled studies were not case-control designs and among case-control studies, key design aspects were not often described. The absence of information about study design elements and underlying assumptions in case-control studies limits the ability to establish the effect measured by the study and the evidentiary value of the study might be underestimated. Copyright © 2016 Elsevier B.V. All rights reserved.

How to Study: The Neglected Basic.

ERIC Educational Resources Information Center

Wilcox, Wayne C.; Wilson, Brent G.

This paper examines knowledge of studying--knowing how and when to apply study strategies. Study strategies may be classified into three categories: memory strategies, comprehension strategies, and problem-solving strategies. Memory-study strategies help students remember what they study. Five attributes often characterize memory strategies:…

The healthy men study: design and recruitment considerations for environmental epidemiologic studies in male reproductive health

EPA Science Inventory

Study Objective: To describe study conduct and response and participant characteristics. Design: Prospective cohort study. Setting: Participants were male partners of women enrolled in a community-based study of drinking water disinfection by-products and pregnancy healt...

Causal Inference in Retrospective Studies.

ERIC Educational Resources Information Center

Holland, Paul W.; Rubin, Donald B.

1988-01-01

The problem of drawing causal inferences from retrospective case-controlled studies is considered. A model for causal inference in prospective studies is applied to retrospective studies. Limitations of case-controlled studies are formulated concerning relevant parameters that can be estimated in such studies. A coffee-drinking/myocardial…

The CDC SHIELD Orange County Project – Baseline Multi Drug-Resistant Organism (MDRO) Prevalence in a Southern California Region

PubMed Central

Singh, Raveena D; Jernigan, John A; Slayton, Rachel B; Stone, Nimalie D; McKinnell, James A; Miller, Loren G; Kleinman, Ken; Heim, Lauren; Dutciuc, Tabitha D; Estevez, Marlene; Gussin, Gabrielle; Chang, Justin; Peterson, Ellena M; Evans, Kaye D; Lee, Bruce Y; Mueller, Leslie E; Bartsch, Sarah M; Zahn, Matthew; Janssen, Lynn; Weinstein, Robert A; Hayden, Mary K; Gohil, Shruti K; Park, Steven; Tam, Steven; Saavedra, Raheeb; Yamaguchi, Stacey; Custodio, Harold; Nguyen, Jenny; Tjoa, Thomas; He, Jiayi; O’Donnell, Kathleen; Coady, Micaela H; Platt, Richard; Huang, Susan S

2017-01-01

Abstract Background MDROs can spread between hospitals, nursing homes (NH), and long-term acute care facilities (LTACs) via shared patients. SHIELD OC is a regional decolonization collaborative involving 38 of 104 countywide adult facilities identified by their high degree of direct and indirect patient sharing with one another. We report baseline MDRO prevalence in these facilities. Methods Adult patients in 38 facilities (17 hospitals, 18 NHs, 3 LTACs) underwent point-prevalence screening between September 2016–April 2017 for MRSA, VRE, ESBL, and CRE using nares, skin (axilla/groin), and peri-rectal swabs. In NHs and LTACs, residents were randomly selected until 50 sets of swabs were obtained. Swabbing in hospitals involved all patients in contact precautions. An additional set of swabs were also performed for all LTAC admissions from November 2016–February 2017. Results The overall prevalence of any MDRO among patients was 64% (44%–88%) in NHs, 80% (range 72%–86%) in LTACs, and 64% (54–84%) in hospitals (contact precaution patients) (Table 1). Only 25%, 64%, and 81% of patients were already known to harbor an MDRO in NHs, LTACs, and hospitals, respectively. Known MDRO patients also harbored another MDRO 49%, 63%, and 34% of the time for NHs, LTACs, and hospitals, respectively. In LTACs, MDRO point prevalence was 38% higher than the usual admission prevalence (65% higher for MRSA, 34% higher for VRE, 95% higher for ESBL, and 50% higher for CRE). Conclusion MDRO carriage in highly inter-connected NHs and LTACs was widespread, rivaling that found in hospitalized patients on contact precautions. MRSA, VRE, and ESBL carriage far outnumbered CRE carriage. A history of MDRO was insensitive for identifying MDRO carriers, and many patients carried multiple MDROs. The extensive MDRO burden and transmission in long-term care settings suggests that regional MDRO prevention efforts must include MDRO control in long-term care facilities. Disclosures R. D. Singh, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; J. A. McKinnell, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; L. G. Miller, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; K. Kleinman, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Molnlycke: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; L. Heim, Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; T. D. Dutciuc, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; M. Estevez, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; G. Gussin, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; L’Oreal: Consultant, Consulting fee; J. Chang, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; E. M. Peterson, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; B. Y. Lee, GSK: Consultant, Consulting fee; R. A. Weinstein, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Molnlycke: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; OpGen Company: Study support, Provided services at no charge; M. K. Hayden, Sage Products: Receipt of contributed product, Sage is contributing product to healthcare facilities participating in a regional collaborative on which I am a co-investigator. Neither I nor my hospital receive product.; Clorox: Receipt of contributed product, Research support; CDC: Grant Investigator and Receipt of contributed product, Research grant; Molnlycke: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; OpGen Company: Study support, Provided services at no charge for studies; S. K. Gohil, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; S. Park, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; S. Tam, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; R. Saavedra, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; S. Yamaguchi, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; H. Custodio, Xttrium Laboratories: Study coordination, Conducting studies in healthcare facilities that are receiving contributed product; Sage Products: Study coordination, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Study coordination, Conducting studies in healthcare facilities that are receiving contributed product; J. Nguyen, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; T. Tjoa, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; J. He, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; M. H. Coady, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Molnlycke: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; R. Platt, Sage Products: Receipt of contributed product, Conducting clinical studies in which participating healthcare facilities are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting clinical studies in which participating healthcare facilities are receiving contributed product; Clorox: Receipt of contributed product, Conducting clinical studies in which participating healthcare facilities are receiving contributed product; receive research funds from Clorox, but Clorox has no role in the design; Molnlycke: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; S. S. Huang, Sage Products: Receipt of contributed product, Conducting studies in which participating healthcare facilities are receiving contributed product (no contribution in submitted abstract), Participating healthcare facilities in my studies received contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in which participating healthcare facilities are receiving contributed product (no contribution in submitted abstract), Participating healthcare facilities in my studies received contributed product; Clorox: Receipt of contributed product, Conducting studies in which participating healthcare facilities are receiving contributed product (no contribution in submitted abstract), Participating healthcare facilities in my studies received contributed product; 3M: Receipt of contributed product, Conducting studies in which participating healthcare facilities are receiving contributed product (no contribution in submitted abstract), Participating healthcare facilities in my studies received contributed product; Molnlycke: Receipt of contributed product, Conducting studies in which participating healthcare facilities are receiving contributed product (no contribution in submitted abstract), Participating healthcare facilities in my studies received contributed product

Challenges to Effective Implementation of Christian Religious Studies Curriculum: A Study of Secondary School Pupils in Ebonyi State of Nigeria

ERIC Educational Resources Information Center

Njoku, N. C.; Njoku, D. I.

2015-01-01

The study is designed to investigate challenges to effective implementation of Christian Religious Studies among secondary school pupils in Ebonyi state. Two research questions were raised to guide the study. The study adopted a descriptive survey design. Ebonyi state is the area of study and the population comprised all the 232 CRS teachers in…

The Army Study Program, FY 1982.

DTIC Science & Technology

1982-05-31

COMPLETED, DELETED, AND DEFERRED STUDIES (FOR THE PERIOD: 10/01/81 TO 05/31/82) STUDY TITLE SPONSOR METHOD CAT ACTION STUDY # SUBMILLIMETER MODELING...Studies and Analyses Agencies and Reference Facilities ............... C-1 Appendix D: Completed, Deleted, and Deferred Studies. ....... D-1 Appendix...understanding of relevant issues and lead to conclusions and recommendations for use by decisionmakers. The central purpose of each study is to support action

Study Habits and Academic Performance of Secondary School Students in Mathematic: A Case Study of Selected Secondary Schools in Uyo Local Education Council

ERIC Educational Resources Information Center

Sakirudeen, Abisola Oladeni; Sanni, Kudirat Bimbo

2017-01-01

The study examined study habits and academic performance of secondary school students in Mathematics. A case study of selected secondary schools in Uyo Local Education Council. The main purpose of the study was to investigate the relationship between study habits and academic performance of secondary school students in Mathematics. To carry out…

An Analysis of the Academic Achievement of the Students Who Listen to Music While Studying

ERIC Educational Resources Information Center

Umzdas, Serpil

2015-01-01

This study's aim is to examine the correlation between the study type, the type and quality of the music students listen to while studying as well as their educational level. The participants of the study are 481 students on a scale of different ages listening to music while studying. The data of the study were collected through a survey…

Study Habit and Its Impact on Secondary School Students' Academic Performance in Biology in the Federal Capital Territory, Abuja

ERIC Educational Resources Information Center

Ebele, Uju F.; Olofu, Paul A.

2017-01-01

Study habits is how one studies. That is, the habits which students form during their school years. Without good study habits, a student cannot succeed. Thus, this study investigated the impact of study habits on secondary school students' academic performance in the Federal Capital Territory, Abuja. The study was guided by one null hypothesis.…

Balancing the Values of Ethnic Studies and Academe: Exploring Efforts to Advance the Organizational Stability of American Indian and Asian American Studies

ERIC Educational Resources Information Center

Kimura-Walsh, Erin Fukiko

2009-01-01

This study examines Ethnic Studies' efforts to gain institutional stability at the university. The issue is explored through a qualitative, multi-case study of Ethnic Studies units, specifically American Indian and Asian American Studies at San Francisco State University and University of California, Los Angeles. To gain insight into their…

Studying the Longitudinal Study. I. Introduction: Do Impromptu Essays Show Changes in Critical Thinking over the Span of College? Cautions and Insights from a Pilot Case Study.

ERIC Educational Resources Information Center

Clark, Francelia

The problematic results of longitudinal studies on college writing indicate the need for multidimensional studies to be able to explore perceptible changes in students' writing. Accordingly a small pilot case study, to explore the promise and the limitations of doing a longitudinal multidimensional study, investigated whether impromptu essays…

To What did They Consent? Understanding Consent Among Low Literacy Participants in a Microbicide Feasibility Study in Mazabuka, Zambia.

PubMed

Munalula-Nkandu, Esther; Ndebele, Paul; Siziya, Seter; Munthali, J C

2015-12-01

We conducted a study to review the consenting process in a vaginal microbicide feasibility study conducted in Mazabuka, Zambia. Participants were drawn from those participating in the microbicide study. A questionnaire and focus group discussion were used to collect information on participants' understanding of study aims, risks and benefits. Altogether, 200 participants took part in this study. The results of the study showed that while all participants signed or endorsed their thumbprints to the consent forms, full informed consent was not attained from most of the participants since 77% (n = 154) of the participants had numerous questions about the study and 34% (n = 68) did not know who to get in touch with concerning the study. Study objectives were not fully understood by over 61% of the participants. Sixty four percent of the participants were not sure of the risks of taking part in the microbicide study. A significant number thought the study was all about determining their HIV status. Some participants were concerned that their partners were not on the trial as they were convinced that being on the study meant that that they had a lifetime protection from HIV infection. The process of obtaining consent was inadequate as various phases of the study were not fully understood. We recommend the need for researchers to reinforce the consenting process in all studies and more so when studies are conducted in low literacy populations. © 2014 John Wiley & Sons Ltd.

Occupational factors and pancreatic cancer.

PubMed Central

Norell, S; Ahlbom, A; Olin, R; Erwald, R; Jacobson, G; Lindberg-Navier, I; Wiechel, K L

1986-01-01

The relation between occupational factors and pancreatic cancer has been studied by two different approaches: a population based case-control study with two series of controls and a retrospective cohort study based on register data. With both approaches, some support was found for an association with occupational exposure to petroleum products. Associations were also indicated with exposure to paint thinner (case-control study) and work in painting and in paint and varnish factories (cohort study), for exposure to detergents, floor cleaning agents, or polish (case-control study) and with floor polishing or window cleaning (cohort study), and for exposure to refuse (case-control study) and work in refuse disposal plants (cohort study). PMID:3790458

Comparing Management Approaches for Automatic Test Systems: A Strategic Missile Case Study

DTIC Science & Technology

2005-03-01

ground up, and is commonly conducted following five methods : ethnography , grounded theory , case study , phenomenological study , and biography...traditions frequently used (Creswell, 1998:5). The five traditions are biography, phenomenological study , grounded theory study , ethnography , and... Ethnography Biography Case Study Grounded Theory

Analysis of 2-Week Data from Two Randomized, Controlled Trials Conducted in Subjects with Frequent Heartburn Treated with Esomeprazole 20 mg.

PubMed

Katz, Philip O; Le Moigne, Anne; Pollack, Charles

2017-05-01

These secondary analyses used data from 2 similarly designed studies in subjects experiencing frequent heartburn to evaluate the efficacy of esomeprazole 20 mg once daily for 2 weeks, which reflects the approved over-the-counter dosage and duration. Subjects without endoscopically identified erosive esophagitis who were experiencing heartburn for ≥6 months and ≥4 of 7 days prior to baseline (study 1, N = 368; study 2, N = 349) were randomly assigned to receive double-blind treatment with esomeprazole 40 or 20 mg (administered as esomeprazole magnesium trihydrate 44.5 and 22.3 mg, respectively) or placebo once daily for 4 weeks. Subjects recorded the severity of heartburn in a daily diary, and investigators assessed subjects at each study visit. Two-week assessments were the primary end points of interest in these analyses and included the percentage of subjects with complete heartburn resolution (no episodes during 7 consecutive days), time to sustained complete heartburn resolution (the first of 7 consecutive episode-free days), and heartburn relief (no episodes other than ≤1 mild episode during 7 consecutive days). At week 2, the percentages of subjects who experienced complete heartburn resolution were significantly greater with esomeprazole 40 mg (study 1, 26.1%; study 2, 35.3%) and 20 mg (study 1, 25.2%; study 2, 35.7%) compared with placebo (study 1, 9.0%; study 2, 3.4%) (all, P ≤ 0.001). Beginning on day 1, the percentages of subjects who experienced sustained heartburn resolution was significantly greater in the groups treated with esomeprazole 40 mg (study 1, 19%; study 2, 19%; P < 0.0001) and 20 mg (study 1, 10%; study 2, 15%; P < 0.05) compared with the group that received placebo (study 1, 2%; study 2, 1%). Additionally, at week 2, the percentages of subjects experiencing heartburn relief were significantly greater with esomeprazole 40 mg (study 1, 35.3%; study 2, 40.5%) and 20 mg (study 1, 34.5%; study 2, 46.4%) compared with placebo (study 1, 16.5%; study 2, 8.6%) (all, P ≤ 0.001). The results of this study demonstrate that once-daily treatment with esomeprazole 20 mg for 2 weeks effectively resolved subjects׳ heartburn compared with placebo, beginning on day 1. Studies precede FDA Act 801 clinical trial registration and results submission requirements. Copyright © 2017 Elsevier HS Journals, Inc. All rights reserved.

Poor replication validity of biomedical association studies reported by newspapers

PubMed Central

Smith, Andy; Boraud, Thomas; Gonon, François

2017-01-01

Objective To investigate the replication validity of biomedical association studies covered by newspapers. Methods We used a database of 4723 primary studies included in 306 meta-analysis articles. These studies associated a risk factor with a disease in three biomedical domains, psychiatry, neurology and four somatic diseases. They were classified into a lifestyle category (e.g. smoking) and a non-lifestyle category (e.g. genetic risk). Using the database Dow Jones Factiva, we investigated the newspaper coverage of each study. Their replication validity was assessed using a comparison with their corresponding meta-analyses. Results Among the 5029 articles of our database, 156 primary studies (of which 63 were lifestyle studies) and 5 meta-analysis articles were reported in 1561 newspaper articles. The percentage of covered studies and the number of newspaper articles per study strongly increased with the impact factor of the journal that published each scientific study. Newspapers almost equally covered initial (5/39 12.8%) and subsequent (58/600 9.7%) lifestyle studies. In contrast, initial non-lifestyle studies were covered more often (48/366 13.1%) than subsequent ones (45/3718 1.2%). Newspapers never covered initial studies reporting null findings and rarely reported subsequent null observations. Only 48.7% of the 156 studies reported by newspapers were confirmed by the corresponding meta-analyses. Initial non-lifestyle studies were less often confirmed (16/48) than subsequent ones (29/45) and than lifestyle studies (31/63). Psychiatric studies covered by newspapers were less often confirmed (10/38) than the neurological (26/41) or somatic (40/77) ones. This is correlated to an even larger coverage of initial studies in psychiatry. Whereas 234 newspaper articles covered the 35 initial studies that were later disconfirmed, only four press articles covered a subsequent null finding and mentioned the refutation of an initial claim. Conclusion Journalists preferentially cover initial findings although they are often contradicted by meta-analyses and rarely inform the public when they are disconfirmed. PMID:28222122

Poor replication validity of biomedical association studies reported by newspapers.

PubMed

Dumas-Mallet, Estelle; Smith, Andy; Boraud, Thomas; Gonon, François

2017-01-01

To investigate the replication validity of biomedical association studies covered by newspapers. We used a database of 4723 primary studies included in 306 meta-analysis articles. These studies associated a risk factor with a disease in three biomedical domains, psychiatry, neurology and four somatic diseases. They were classified into a lifestyle category (e.g. smoking) and a non-lifestyle category (e.g. genetic risk). Using the database Dow Jones Factiva, we investigated the newspaper coverage of each study. Their replication validity was assessed using a comparison with their corresponding meta-analyses. Among the 5029 articles of our database, 156 primary studies (of which 63 were lifestyle studies) and 5 meta-analysis articles were reported in 1561 newspaper articles. The percentage of covered studies and the number of newspaper articles per study strongly increased with the impact factor of the journal that published each scientific study. Newspapers almost equally covered initial (5/39 12.8%) and subsequent (58/600 9.7%) lifestyle studies. In contrast, initial non-lifestyle studies were covered more often (48/366 13.1%) than subsequent ones (45/3718 1.2%). Newspapers never covered initial studies reporting null findings and rarely reported subsequent null observations. Only 48.7% of the 156 studies reported by newspapers were confirmed by the corresponding meta-analyses. Initial non-lifestyle studies were less often confirmed (16/48) than subsequent ones (29/45) and than lifestyle studies (31/63). Psychiatric studies covered by newspapers were less often confirmed (10/38) than the neurological (26/41) or somatic (40/77) ones. This is correlated to an even larger coverage of initial studies in psychiatry. Whereas 234 newspaper articles covered the 35 initial studies that were later disconfirmed, only four press articles covered a subsequent null finding and mentioned the refutation of an initial claim. Journalists preferentially cover initial findings although they are often contradicted by meta-analyses and rarely inform the public when they are disconfirmed.

Overdiagnosis across medical disciplines: a scoping review.

PubMed

Jenniskens, Kevin; de Groot, Joris A H; Reitsma, Johannes B; Moons, Karel G M; Hooft, Lotty; Naaktgeboren, Christiana A

2017-12-27

To provide insight into how and in what clinical fields overdiagnosis is studied and give directions for further applied and methodological research. Scoping review. Medline up to August 2017. All English studies on humans, in which overdiagnosis was discussed as a dominant theme. Studies were assessed on clinical field, study aim (ie, methodological or non-methodological), article type (eg, primary study, review), the type and role of diagnostic test(s) studied and the context in which these studies discussed overdiagnosis. From 4896 studies, 1851 were included for analysis. Half of all studies on overdiagnosis were performed in the field of oncology (50%). Other prevalent clinical fields included mental disorders, infectious diseases and cardiovascular diseases accounting for 9%, 8% and 6% of studies, respectively. Overdiagnosis was addressed from a methodological perspective in 20% of studies. Primary studies were the most common article type (58%). The type of diagnostic tests most commonly studied were imaging tests (32%), although these were predominantly seen in oncology and cardiovascular disease (84%). Diagnostic tests were studied in a screening setting in 43% of all studies, but as high as 75% of all oncological studies. The context in which studies addressed overdiagnosis related most frequently to its estimation, accounting for 53%. Methodology on overdiagnosis estimation and definition provided a source for extensive discussion. Other contexts of discussion included definition of disease, overdiagnosis communication, trends in increasing disease prevalence, drivers and consequences of overdiagnosis, incidental findings and genomics. Overdiagnosis is discussed across virtually all clinical fields and in different contexts. The variability in characteristics between studies and lack of consensus on overdiagnosis definition indicate the need for a uniform typology to improve coherence and comparability of studies on overdiagnosis. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

38 CFR 1.17 - Evaluation of studies relating to health effects of radiation exposure.

Code of Federal Regulations, 2012 CFR

2012-07-01

... health effects of radiation exposure. (a) From time to time, the Secretary shall publish evaluations of... paragraph a valid study is one which: (i) Has adequately described the study design and methods of data... studies affecting epidemiological assessments including case series, correlational studies and studies...

38 CFR 1.17 - Evaluation of studies relating to health effects of radiation exposure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... health effects of radiation exposure. (a) From time to time, the Secretary shall publish evaluations of... paragraph a valid study is one which: (i) Has adequately described the study design and methods of data... studies affecting epidemiological assessments including case series, correlational studies and studies...

38 CFR 1.17 - Evaluation of studies relating to health effects of radiation exposure.

Code of Federal Regulations, 2014 CFR

2014-07-01

... health effects of radiation exposure. (a) From time to time, the Secretary shall publish evaluations of... paragraph a valid study is one which: (i) Has adequately described the study design and methods of data... studies affecting epidemiological assessments including case series, correlational studies and studies...

38 CFR 1.17 - Evaluation of studies relating to health effects of radiation exposure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... health effects of radiation exposure. (a) From time to time, the Secretary shall publish evaluations of... paragraph a valid study is one which: (i) Has adequately described the study design and methods of data... studies affecting epidemiological assessments including case series, correlational studies and studies...

38 CFR 1.17 - Evaluation of studies relating to health effects of radiation exposure.

Code of Federal Regulations, 2011 CFR

2011-07-01

... health effects of radiation exposure. (a) From time to time, the Secretary shall publish evaluations of... paragraph a valid study is one which: (i) Has adequately described the study design and methods of data... studies affecting epidemiological assessments including case series, correlational studies and studies...

Matching Three Classifications of Secondary Students to Differential Levels of Study Guides.

ERIC Educational Resources Information Center

Horton, Steven V.; And Others

1991-01-01

This study examined the effectiveness of matching 82 secondary students (learning disabled, remedial, and nondisabled) to differential levels of study guides. The study evaluated two treatment conditions (multilevel study guides containing different levels of referential cues, and single-level study guides without referential cues), used in…

Research on Community Bands: Past, Present, and Future

ERIC Educational Resources Information Center

Rohwer, Debbie

2016-01-01

The purpose of this review of literature was to synthesize findings of studies investigating community bands. This review of literature centers on research that has been conducted on community bands in status studies, historical/cultural studies, pedagogical studies, health and wellness studies, and intergenerational studies. The last section of…

40 CFR 792.33 - Study director.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Study director. 792.33 Section 792.33...) GOOD LABORATORY PRACTICE STANDARDS Organization and Personnel § 792.33 Study director. For each study... thereof, shall be identified as the study director. The study director has overall responsibility for the...

40 CFR 160.33 - Study director.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Study director. 160.33 Section 160.33... PRACTICE STANDARDS Organization and Personnel § 160.33 Study director. For each study, a scientist or other... the study director. The study director has overall responsibility for the technical conduct of the...

18 CFR 5.12 - Comments on proposed study plan.

Code of Federal Regulations, 2010 CFR

2010-04-01

... study plan. 5.12 Section 5.12 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... PROCESS § 5.12 Comments on proposed study plan. Comments on the potential applicant's proposed study plan, including any revised information or study requests, must be filed within 90 days after the proposed study...

29 CFR 1607.5 - General standards for validity studies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 4 2010-07-01 2010-07-01 false General standards for validity studies. 1607.5 Section 1607... studies. A. Acceptable types of validity studies. For the purposes of satisfying these guidelines, users may rely upon criterion-related validity studies, content validity studies or construct validity...

40 CFR 160.33 - Study director.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Study director. 160.33 Section 160.33... PRACTICE STANDARDS Organization and Personnel § 160.33 Study director. For each study, a scientist or other... the study director. The study director has overall responsibility for the technical conduct of the...

Learning Social Studies through Mastery Approach

ERIC Educational Resources Information Center

Adeyemi, B. A.

2007-01-01

This study examined learning Social Studies by investigating the effectiveness of mastery approach on students' performance in Social Studies of two groups of students drawn from Osun State College of Education, Ila-Orangun and University of Uyo, Ila-Orangun Study Centre which consisted of 200 level Social Studies students and 200 level degree…

78 FR 21611 - Guidance for Industry on Self-Selection Studies for Nonprescription Drug Products; Availability

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-11

... recommendations regarding study design, study conduct, and final reporting of self-selection studies. The guidance...] Guidance for Industry on Self-Selection Studies for Nonprescription Drug Products; Availability AGENCY... announcing the availability of a guidance for industry entitled ``Self-Selection Studies for Nonprescription...

Personal Study Planning in Doctoral Education in Industrial Engineering

ERIC Educational Resources Information Center

Lahenius, K.; Martinsuo, M.

2010-01-01

The duration of doctoral studies has increased in Europe. Personal study planning has been considered as one possible solution to help students in achieving shorter study times. This study investigates how doctoral students experience and use personal study plans in one university department of industrial engineering. The research material…

The Development of Study Orientations and Study Success in Students of Pharmacy

ERIC Educational Resources Information Center

Nieminen, Juha; Lindblom-Ylanne, Sari; Lonka, Kirsti

2004-01-01

In research literature, two study orientations have been identified: meaning orientation and reproducing orientation. Few studies have examined how study orientations and conceptions of knowledge (epistemologies) interrelate. Further, longitudinal studies of the development of orientations and of conceptions of knowledge in relation to academic…

APPROACHES FOR MEASURING APPLICATOR EXPOSURE IN THE AGRICULTURAL HEALTH STUDY/PESTICIDE EXPOSURE STUDY

EPA Science Inventory

The Agricultural Health Study (AHS) is a prospective epidemiologic study of a large cohort of pesticide applicators and their spouses in Iowa and North Carolina. The Pesticide Exposure Study is a sub-study to evaluate exposure factors and to provide data to assess exposure cla...

Eastern Renewable Generation Integration Study | Grid Modernization | NREL

Science.gov Websites

Eastern Renewable Generation Integration Study Eastern Renewable Generation Integration Study Using perform the Eastern Renewable Generation Integration Study (ERGIS), a scenario-based study of four % targets under the study assumptions sometimes requires coordinating operations from Montreal to Miami and

Interconnections Seam Study | Energy Analysis | NREL

Science.gov Websites

Interconnections Seam Study Interconnections Seam Study Through the Interconnections Seam Study between the interconnections. This study will quantify the value of strengthening the connections (or Peer Review - Interconnections Seam Study to learn more. Our Approach To quantify the value of

Peace Studies.

ERIC Educational Resources Information Center

Perrone, Vito

1986-01-01

Themes that should be included in an elementary and secondary peace studies curriculum are discussed in this newsletter essay. Social studies teachers must use great discretion as to what topics in the peace studies curriculum are taught at what level. The study of nuclear arms should be included in peace studies at the secondary level. Research…

A Study on Preschoolers' Conceptual Perceptions of States of Matter: A Case Study of Turkish Students

ERIC Educational Resources Information Center

Demirbas, Murat; Ertuðrul, Nurcan

2014-01-01

The purpose of the present study is to identify preschoolers' conceptual perceptions of states of matter, this issue that they often come across in their daily and social life. The study was designed as a qualitative case study. The population of the study was comprised of 25 preschoolers studying at two primary schools located in Kýrýkkale and…

How Can I Describe Social Studies Curriculum in the First Three Years of Primary School? A Case Study

ERIC Educational Resources Information Center

Aktan, Sümer

2016-01-01

The aim of this study is to determine the opinions of a multigrade class teacher on the nature of social studies lesson, the structure of the social studies curriculum, and the teaching process of social studies lesson. The study was structured in line with a holistic single case design which is contained in the tradition of qualitative research.…

Liquid Rocket Booster (LRB) for the Space Transportation System (STS) Systems Study. Amendment 13: Orientation meeting

NASA Technical Reports Server (NTRS)

1990-01-01

The topics are presented in viewgraph form and include the following: LRB study results summary -- Feb. 1989; LRB study results -- Jan. 1990; Shuttle configuration with booster options; LRB study results -- Sept. 1990; LRB statement of work tasks; ground rules and assumptions; study flow of design, manufacturing/production, and test program/certification; study products; study schedule; and candidate 1.5 stage engine arrangements.

Into the Curriculum: Art/Social Studies: The Arts and Native Americans [and] Reading/Language Arts/Social Studies: Haiku Poetry [and] Reading/Language Arts: Let's Make a Book [and] Science: The Microscope [and] Social Studies: Native American Life [and] Social Studies/Foreign Languages: Pasta Perfect.

ERIC Educational Resources Information Center

Wheeler, Kathleen; Lane, Patricia J.; Yates, Marci Fletcher; Bikhazi, Cristi; Davis, Shirley; Cook, Sybilla A.

1998-01-01

Provides lesson plans for grades one to three science, grades two to six social studies/Italian, grade three reading/language arts, grade four and five reading/language arts/social studies, grade five art/social studies, and grades five and six social studies. Lists print and nonprint resources and discusses library media skills and subject area…

CORRELATIONS BETWEEN INTELLIGENCE, HEAD CIRCUMFERENCE AND HEIGHT: EVIDENCE FROM TWO SAMPLES IN SAUDI ARABIA.

PubMed

Bakhiet, Salaheldin Farah Attallah; Essa, Yossry Ahmed Sayed; Dwieb, Amira Mahmood Mohsen; Elsayed, Abdelkader Mohamed Abdelkader; Sulman, Afra Sulman Mohammed; Cheng, Helen; Lynn, Richard

2017-03-01

This study was based on two independent studies which in total consisted of 1812 school pupils aged 6-12 years in Saudi Arabia. Study I consisted of 1591 school pupils (609 boys and 982 girls) attending state schools, and Study II consisted of 211 boys with learning disabilities. Intelligence (measured using the Standard Progressive Matrices Plus for Study I and the Standard Progressive Matrices for Study II), head size and height were measured for the two samples. The results showed that intelligence was statistically significantly correlated with head circumference (r=0.350, p<0.001 for Study I and r=0.168, p<0.05 for Study II) and height (r=0.271, p<0.001 for Study I and r=0.178, p<0.05 for Study II).

Compassionate Parenting as a Key to Satisfaction, Efficacy and Meaning Among Mothers of Children with Autism.

PubMed

Conti, Regina

2015-07-01

Two studies examine the role of compassionate and self-image parenting goals in the experience of mothers of children with autism. In Study 1, a comparison sample was included. Study 1 included measures of parenting goals, life satisfaction, family life satisfaction, parenting satisfaction, and meaning in life. Study 2 incorporated a measure of parenting efficacy. Study 1 showed that mothers of children with autism were higher than comparison mothers in compassionate parenting goals. In both studies, compassionate parenting predicted positive outcomes including higher parenting satisfaction (both studies), family life satisfaction, meaning in life (Study 1) and higher parenting efficacy (Study 2). These studies support the notion that compassionate parenting is a key to satisfaction for mothers of children with autism.

Methodological considerations in cost of illness studies on Alzheimer disease

PubMed Central

2012-01-01

Cost-of-illness studies (COI) can identify and measure all the costs of a particular disease, including the direct, indirect and intangible dimensions. They are intended to provide estimates about the economic impact of costly disease. Alzheimer disease (AD) is a relevant example to review cost of illness studies because of its costliness.The aim of this study was to review relevant published cost studies of AD to analyze the method used and to identify which dimension had to be improved from a methodological perspective. First, we described the key points of cost study methodology. Secondly, cost studies relating to AD were systematically reviewed, focussing on an analysis of the different methods used. The methodological choices of the studies were analysed using an analytical grid which contains the main methodological items of COI studies. Seventeen articles were retained. Depending on the studies, annual total costs per patient vary from $2,935 to $52, 954. The methods, data sources, and estimated cost categories in each study varied widely. The review showed that cost studies adopted different approaches to estimate costs of AD, reflecting a lack of consensus on the methodology of cost studies. To increase its credibility, closer agreement among researchers on the methodological principles of cost studies would be desirable. PMID:22963680

Response rates in case-control studies of cancer by era of fieldwork and by characteristics of study design.

PubMed

Xu, Mengting; Richardson, Lesley; Campbell, Sally; Pintos, Javier; Siemiatycki, Jack

2018-04-09

The purpose of this study was to describe time trends in response rates in case-control studies of cancer and identify study design factors that influence response rate. We reviewed 370 case-control studies of cancer published in 12 journals during indicator years in each of the last four decades. We estimated time trends of response rates and reasons for nonresponse in each of the following types of study subjects: cases, medical source controls, and population controls. We also estimated response rates according to characteristics of study context. Median response rates among cases and population controls were between 75% and 80% in the 1970s. Between 1971 and 2010, study response rates declined by 0.31% per year for cases and 0.78% for population controls. Only a minority of studies reported reasons for nonparticipation; subject refusal was the most common reported reason. Studies conducted in North America had lower median response rates than studies conducted in Europe. In-person and telephone interviews elicited higher response rates than mail questionnaires. Response rates from case-control studies of cancer have declined, and this could threaten the validity of results derived from these studies. Copyright © 2018 Elsevier Inc. All rights reserved.

Have we progressed in the surgical literature? Thirty-year trends in clinical studies in 3 surgical journals.

PubMed

Shawhan, Robert R; Hatch, Quinton M; Bingham, Jason R; Nelson, Daniel W; Fitzpatrick, Emile B; McLeod, Robin; Johnson, Eric K; Maykel, Justin A; Steele, Scott R

2015-01-01

We practice in an era of evidence-based medicine. In 1993, Solomon and McLeod published an article examining study designs in 3 surgical journals from 1980 and 1990. The purpose of this study was to evaluate subsequent 30-year trends in the quality of selected literature. All of the articles from Diseases of the Colon & Rectum, Surgery, and the British Journal of Surgery during 2000 and 2010 were classified by study design. Nonclinical studies were substratified by animal/laboratory, surgical technique, editorial/review, or miscellaneous articles. Clinical articles were categorized as case or comparative studies, further categorized by study design, and rated on a 10-point scale to determine strength. We compared interobserver reliability using a random sample. This study was conducted at 3 North American medical centers. Patients described in the scope of the literature were included in this study. Frequency, type, and strength of study design were measured. We evaluated 1911 articles (967 clinical; 17% comparative). There was a significant increase in multicenter clinical studies (from 12% to 27%; p < 0.0001) and mean study population (from 326 to 6775; p < 0.05). Studies using administrative data increased from 14% to 43% (p < 0.0001). Case reports decreased from 16% to 7% of all clinical studies (p < 0.001), whereas the percentage of comparative studies increased from 14% to 21% (p = 0.001). The percentage of randomized controlled trials did not increase significantly (8.5% in 2000; 10.0% in 2010; p = 0.44). The mean 10-point score for comparative studies was 6.7 for both years (p = 0.50). There was good interobserver agreement in the classification of studies (κ = 0.70) and moderate agreement in scoring comparative studies (κ = 0.47). This descriptive study cannot fully account for the reasons behind the identified differences. Comparative and multicenter studies, mean study population, and the use of administrative data increased from 2000 to 2010. This suggests that increased use of administrative databases has allowed larger populations of patients from more institutions to be studied and may be more generalizable. Researchers should strive toward improving the level of evidence (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A167).

Endoscopy in neutropenic and/or thrombocytopenic patients

PubMed Central

Tong, Michelle C; Tadros, Micheal; Vaziri, Haleh

2015-01-01

AIM: To evaluate the safety of endoscopic procedures in neutropenic and/or thrombocytopenic cancer patients. METHODS: We performed a literature search for English language studies in which patients with neutropenia and/or thrombocytopenia underwent endoscopy. Studies were included if endoscopic procedures were used as part of the evaluation of neutropenic and/or thrombocytopenic patients, yielding 13 studies. Two studies in which endoscopy was not a primary evaluation tool were excluded. Eleven relevant studies were identified by two independent reviewers on PubMed, Scopus, and Ovid databases. RESULTS: Most of the studies had high diagnostic yield with relatively low complication rates. Therapeutic endoscopic interventions were performed in more than half the studies, including high-risk procedures, such as sclerotherapy. Platelet transfusion was given if counts were less than 50000/mm3 in four studies and less than 10000/mm3 in one study. Other thrombocytopenic precautions included withholding of biopsy if platelet count was less than 30000/mm3 in one study and less than 20000/mm3 in another study. Two of the ten studies which examined thrombocytopenic patient populations reported bleeding complications related to endoscopy, none of which caused major morbidity or mortality. All febrile neutropenic patients received prophylactic broad-spectrum antibiotics in the studies reviewed. Regarding afebrile neutropenic patients, prophylactic antibiotics were given if absolute neutrophil count was less than 1000/mm3 in one study, if the patient was undergoing colonoscopy and had a high inflammatory condition without clear definition of significance in another study, and if the patient was in an aplastic phase in a third study. Endoscopy was also withheld in one study for severe pancytopenia. CONCLUSION: Endoscopy can be safely performed in patients with thrombocytopenia/neutropenia. Prophylactic platelet transfusion and/or antibiotic administration prior to endoscopy may be considered in some cases and should be individualized. PMID:26674926

Dissemination and implementation: INQRI's potential impact.

PubMed

Titler, Marita G; Wilson, Deleise S; Resnick, Barbara; Shever, Leah L

2013-04-01

Application of research evidence in care delivery improves patient outcomes. Large gaps still exist, however, between recommended care and that used in practice. To increase the understanding of implementation studies, and dissemination of research findings, we present the perspective of investigators from seven Interdisciplinary Nursing Quality Research Initiative (INQRI)-funded studies. To describe implementation strategies, challenges, and lessons learned from conducting 5 INQRI-funded implementation studies, and present 2 case examples of other INQRI studies to illustrate dissemination strategies. Potential impact of study findings are set forth. Qualitative descriptive methods were used for the implementation studies. Case examples were set forth by investigators using reflection questions. Four of the 5 implementation studies focused on clinical topics and 1 on professional development of nurse managers, 4 were multisite studies. Common implementation strategies used across studies addressed education, ongoing interaction with sites, use of implementation tools, and visibility of the projects on the study units. Major challenges were the Institutional Review Board approval process and the short length of time allocated for implementation. Successes and lessons learned included creating excitement about research, packaging of study tools and resources for use by other organizations, and understanding the importance of context when conducting this type of research. Case examples revealed that study findings have been disseminated to study sites and to the health care community through publications and presentations. The potential impact of all 7 studies is far reaching. This study captures several nuanced perspectives from 5 Principal Investigators, who were completing INQRI-funded implementation studies. These nuanced perspectives are important lessons for other scientists embarking on implementation studies. The INQRI case examples illustrate important dissemination strategies and impact of findings on quality of care.

IDGenerator: unique identifier generator for epidemiologic or clinical studies.

PubMed

Olden, Matthias; Holle, Rolf; Heid, Iris M; Stark, Klaus

2016-09-15

Creating study identifiers and assigning them to study participants is an important feature in epidemiologic studies, ensuring the consistency and privacy of the study data. The numbering system for identifiers needs to be random within certain number constraints, to carry extensions coding for organizational information, or to contain multiple layers of numbers per participant to diversify data access. Available software can generate globally-unique identifiers, but identifier-creating tools meeting the special needs of epidemiological studies are lacking. We have thus set out to develop a software program to generate IDs for epidemiological or clinical studies. Our software IDGenerator creates unique identifiers that not only carry a random identifier for a study participant, but also support the creation of structured IDs, where organizational information is coded into the ID directly. This may include study center (for multicenter-studies), study track (for studies with diversified study programs), or study visit (baseline, follow-up, regularly repeated visits). Our software can be used to add a check digit to the ID to minimize data entry errors. It facilitates the generation of IDs in batches and the creation of layered IDs (personal data ID, study data ID, temporary ID, external data ID) to ensure a high standard of data privacy. The software is supported by a user-friendly graphic interface that enables the generation of IDs in both standard text and barcode 128B format. Our software IDGenerator can create identifiers meeting the specific needs for epidemiologic or clinical studies to facilitate study organization and data privacy. IDGenerator is freeware under the GNU General Public License version 3; a Windows port and the source code can be downloaded at the Open Science Framework website: https://osf.io/urs2g/ .

The experiences of relatives with the practice of palliative sedation: a systematic review.

PubMed

Bruinsma, Sophie M; Rietjens, Judith A C; Seymour, Jane E; Anquinet, Livia; van der Heide, Agnes

2012-09-01

Guidelines about palliative sedation typically include recommendations to protect the well-being of relatives. The aim of this study was to systematically review evidence on the experiences of relatives with the practice of palliative sedation. PubMed, Embase, Web of Science, PsycINFO, and CINAHL were searched for empirical studies on relatives' experiences with palliative sedation. We investigated relatives' involvement in the decision-making and sedation processes, whether they received adequate information and support, and relatives' emotions. Of the 564 studies identified, 39 were included. The studies (30 quantitative, six qualitative, and three mixed methods) were conducted in 16 countries; three studies were based on relatives' reports, 26 on physicians' and nurses' proxy reports, seven on medical records, and three combined different sources. The 39 studies yielded a combined total of 8791 respondents or studied cases. Caregivers involved relatives in the decision making in 69%-100% of all cases (19 quantitative studies), and in 60%-100% of all cases, relatives were reported to have received adequate information (five quantitative studies). Only two quantitative studies reported on relatives' involvement in the provision of sedation. Despite the fact that the majority of relatives were reported to be comfortable with the use of palliative sedation (seven quantitative studies, four qualitative studies), several studies found that relatives were distressed by the use of sedation (five quantitative studies, five qualitative studies). No studies reported specifically about the support provided to the relatives. Relatives' experiences with palliative sedation are mainly studied from the perspective of proxies, mostly professional caregivers. The majority of relatives seems to be comfortable with the use of palliative sedation; however, they may experience substantial distress by the use of sedation. Copyright © 2012 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.

Characteristics and follow-up of postmarketing studies of conditionally authorized medicines in the EU.

PubMed

Hoekman, Jarno; Klamer, Thea T; Mantel-Teeuwisse, Aukje K; Leufkens, Hubert G M; De Bruin, Marie L

2016-07-01

The aim of the present study was to provide an insight into the characteristics and follow-up of postmarketing studies of medicines that were conditionally authorized in the European Union (EU). We compiled a list of all postmarketing studies attached as specific obligations to the licence of medicines that were granted conditional marketing authorization from January 2006 to April 2014. Studies were characterized based on their objective, design, status upon marketing authorization (MA) and due data set by authorities. They were linked to online study registrations (Clinicaltrials.gov, ENCePP) to determine completion date. We described and associated characteristics of studies and medicines, and determined whether studies were completed on time. A total of 59 postmarketing studies were requested for 21 conditionally authorized medicines. Most studies had an interventional study design (73%), were ongoing upon MA (61%) and aimed to provide additional data on efficacy (45%). Interventional studies were more often ongoing and providing efficacy data, while observational and other studies were more often new and providing safety data. Frequent grounds for requesting postmarketing studies were 'long-term follow-up' and 'increase data on subpopulations'. Of the 34 studies eligible for follow-up analysis, 26 (76%) were completed and 17 (50%) completed on time. Actual completion time took a median (interquartile range) of 274 (-121 to 556) days longer than expected. Our results indicated that most postmarketing studies attached to a conditional marketing authorization were eventually completed but that half were completed with a substantial delay. The observations suggest caution when broadening the use of postmarketing studies for resolving uncertainties about benefits and risks after MA. © 2016 The British Pharmacological Society.

Recruiting vulnerable populations into research: a systematic review of recruitment interventions.

PubMed

UyBico, Stacy J; Pavel, Shani; Gross, Cary P

2007-06-01

Members of vulnerable populations are underrepresented in research studies. To evaluate and synthesize the evidence regarding interventions to enhance enrollment of vulnerable populations into health research studies. Studies were identified by searching MEDLINE, the Web of Science database, personal sources, hand searching of related journals, and article references. Studies that contained data on recruitment interventions for vulnerable populations (minority, underserved, poor, rural, urban, or inner city) and for which the parent study (study for which recruitment was taking place) was an intervention study were included. A total of 2,648 study titles were screened and 48 articles met inclusion criteria, representing 56 parent studies. Two investigators extracted data from each study. African Americans were the most frequently targeted population (82% of the studies), while 46% targeted Hispanics/Latinos. Many studies assessed 2 or more interventions, including social marketing (82% of studies), community outreach (80%), health system recruitment (52%), and referrals (28%). The methodologic rigor varied substantially. Only 40 studies (71%) incorporated a control group and 21% used statistical analysis to compare interventions. Social marketing, health system, and referral recruitment were each found to be the most successful intervention about 35-45% of the studies in which they were attempted, while community outreach was the most successful intervention in only 2 of 16 studies (13%) in which it was employed. People contacted as a result of social marketing were no less likely to enroll than people contacted through other mechanisms. Further work with greater methodologic rigor is needed to identify evidence-based strategies for increasing minority enrollment in research studies; community outreach, as an isolated strategy, may be less successful than other strategies.

Characteristics and follow‐up of postmarketing studies of conditionally authorized medicines in the EU

PubMed Central

Klamer, Thea T.; Mantel‐Teeuwisse, Aukje K.; Leufkens, Hubert G. M.; De Bruin, Marie L.

2016-01-01

Aim The aim of the present study was to provide an insight into the characteristics and follow‐up of postmarketing studies of medicines that were conditionally authorized in the European Union (EU). Methods We compiled a list of all postmarketing studies attached as specific obligations to the licence of medicines that were granted conditional marketing authorization from January 2006 to April 2014. Studies were characterized based on their objective, design, status upon marketing authorization (MA) and due data set by authorities. They were linked to online study registrations (Clinicaltrials.gov, ENCePP) to determine completion date. We described and associated characteristics of studies and medicines, and determined whether studies were completed on time. Results A total of 59 postmarketing studies were requested for 21 conditionally authorized medicines. Most studies had an interventional study design (73%), were ongoing upon MA (61%) and aimed to provide additional data on efficacy (45%). Interventional studies were more often ongoing and providing efficacy data, while observational and other studies were more often new and providing safety data. Frequent grounds for requesting postmarketing studies were ‘long‐term follow‐up’ and ‘increase data on subpopulations’. Of the 34 studies eligible for follow‐up analysis, 26 (76%) were completed and 17 (50%) completed on time. Actual completion time took a median (interquartile range) of 274 (−121 to 556) days longer than expected. Conclusions Our results indicated that most postmarketing studies attached to a conditional marketing authorization were eventually completed but that half were completed with a substantial delay. The observations suggest caution when broadening the use of postmarketing studies for resolving uncertainties about benefits and risks after MA. PMID:26992001

Recruiting Vulnerable Populations into Research: A Systematic Review of Recruitment Interventions

PubMed Central

UyBico, Stacy J.; Pavel, Shani

2007-01-01

Background Members of vulnerable populations are underrepresented in research studies. Objective To evaluate and synthesize the evidence regarding interventions to enhance enrollment of vulnerable populations into health research studies. Data sources Studies were identified by searching MEDLINE, the Web of Science database, personal sources, hand searching of related journals, and article references. Studies that contained data on recruitment interventions for vulnerable populations (minority, underserved, poor, rural, urban, or inner city) and for which the parent study (study for which recruitment was taking place) was an intervention study were included. A total of 2,648 study titles were screened and 48 articles met inclusion criteria, representing 56 parent studies. Two investigators extracted data from each study. Results African Americans were the most frequently targeted population (82% of the studies), while 46% targeted Hispanics/Latinos. Many studies assessed 2 or more interventions, including social marketing (82% of studies), community outreach (80%), health system recruitment (52%), and referrals (28%). The methodologic rigor varied substantially. Only 40 studies (71%) incorporated a control group and 21% used statistical analysis to compare interventions. Social marketing, health system, and referral recruitment were each found to be the most successful intervention about 35–45% of the studies in which they were attempted, while community outreach was the most successful intervention in only 2 of 16 studies (13%) in which it was employed. People contacted as a result of social marketing were no less likely to enroll than people contacted through other mechanisms. Conclusions Further work with greater methodologic rigor is needed to identify evidence-based strategies for increasing minority enrollment in research studies; community outreach, as an isolated strategy, may be less successful than other strategies. PMID:17375358

When a Home is Not a Home: MultiDrug-Resistant Organism (MDRO) Colonization and Environmental Contamination in 28 Nursing Homes (NHs)

PubMed Central

McKinnell, James A; Miller, Loren; Singh, Raveena D; Mendez, Job; Franco, Ryan; Gussin, Gabrielle; Chang, Justin; Dutciuc, Tabitha D; Saavedra, Raheeb; Kleinman, Ken; Peterson, Ellena M; Evans, Kaye D; Heim, Lauren; Miner, Aaron; Estevez, Marlene; Custodio, Harold; Yamaguchi, Stacey; Nguyen, Jenny; Varasteh, Alex; Launer, Bryn; Agrawal, Shalini; Tjoa, Thomas; He, Jiayi; Park, Steven; Tam, Steven; Gohil, Shruti K; Stone, Nimalie D; Steinberg, Karl; Montgomery, Jocelyn; Beecham, Nancy; Huang, Susan S

2017-01-01

Abstract Background The majority of healthcare-associated infections due to MDROs occur in the post-discharge setting. Understanding MDRO spread and containment in NHs can help identify infection prevention activities needed to care for vulnerable patients in a medical home setting. Methods We conducted a baseline point prevalence study of MDRO colonization in residents of 28 Southern California NHs participating in a decolonization trial. In Fall 2016, residents were randomly sampled to obtain a set of 50 nares and skin (axilla/groin) swabs from each NH. Nasal swabs were processed for MRSA and skin swabs were processed for MRSA, VRE, ESBL, and CRE. In addition, environmental swabs were collected from high touch objects in resident rooms (bedrail, call button/TV remote, door knobs, light switch, bathroom) and common areas (nursing station, table, chair, railing, and drinking fountain). Results A total of 2,797 body swabs were obtained from 1400 residents. Overall, 48.6% (N = 680) of residents harbored MDROs. MRSA was found in 37% of residents (29.5% nares, 24.4% skin), followed by ESBL in 16% (Table 1). Resident MDRO status was only known for 11% of MRSA (59/518), 18% ESBL (40/228), 4% VRE (4/99), and none of the CRE (0/13) carriers. Colonization did not differ between long stay (48.8%, 534/1094) vs. post-acute (47.7%, 146/306) residents (P = NS), but bedbound residents were more likely to be MDRO colonized (58.7%, 182/310) vs. ambulatory residents (45.7%, 497/1088, P < 0.001). A total of 560 environmental swabs were obtained with 93% of common areas and 74% of resident rooms having an MDRO+ object with an average of 2.5 and 1.9 objects found to be contaminated (Table 2). Conclusion One in two NH residents are colonized with MDROs, which is largely unknown to the facility. MDRO carriage is associated with total care needs, but not long stay status. Environmental contamination in resident rooms and common areas is common. The burden of MDRO colonization and contamination is sufficiently high that universal strategies to reduce colonization and transmission are warranted. Disclosures J. A. McKinnell, Allergan: Research Contractor, Scientific Advisor and Speaker’s Bureau, Consulting fee, Research support and Speaker honorarium; Achaogen: Research Contractor, Scientific Advisor and Shareholder, Research support; Cempra: Research Contractor and Scientific Advisor, Research support; Theravance: Research Contractor, Research support; Science 37: Research Contractor, Salary; Expert Stewardship, LLC: Board Member and Employee, Salary; Thermo Fisher: Scientific Advisor, Salary; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; L. Miller, 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; R. D. Singh, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; J. Mendez, Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; R. Franco, Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; G. Gussin, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; L’Oreal: Consultant, Consulting fee; J. Chang, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; T. D. Dutciuc, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; R. Saavedra, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; K. Kleinman, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Molnlycke: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; E. M. Peterson, Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; L. Heim, Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; A. Miner, Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; M. Estevez, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; H. Custodio, Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; S. Yamaguchi, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; J. Nguyen, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; A. Varasteh, Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Sage Product: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; B. Launer, 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; S. Agrawal, Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; T. Tjoa, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; J. He, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; S. Park, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; S. Tam, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; 3M: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; S. K. Gohil, Sage Products: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; Clorox: Receipt of contributed product, Conducting studies in healthcare facilities that are receiving contributed product; S. S. Huang, Sage Products: Receipt of contributed product, Conducting studies in which participating healthcare facilities are receiving contributed product (no contribution in submitted abstract), Participating healthcare facilities in my studies received contributed product; Xttrium Laboratories: Receipt of contributed product, Conducting studies in which participating healthcare facilities are receiving contributed product (no contribution in submitted abstract), Participating healthcare facilities in my studies received contributed product; Clorox: Receipt of contributed product, Conducting studies in which participating healthcare facilities are receiving contributed product (no contribution in submitted abstract), Participating healthcare facilities in my studies received contributed product; 3M: Receipt of contributed product, Conducting studies in which participating healthcare facilities are receiving contributed product (no contribution in submitted abstract), Participating healthcare facilities in my studies received contributed product; Molnlycke: Receipt of contributed product, Conducting studies in which participating healthcare facilities are receiving contributed product (no contribution in submitted abstract), Participating healthcare facilities in my studies received contributed product

Assessment of the quality of reporting observational studies in the pediatric dental literature.

PubMed

Butani, Yogita; Hartz, Arthur; Levy, Steven; Watkins, Catherine; Kanellis, Michael; Nowak, Arthur

2006-01-01

The purpose of this assessment was to evaluate reporting of observational studies in the pediatric dental literature. This assessment included the following steps: (1) developing a model for reporting information in clinical dentistry studies; (2) identifying treatment comparisons in pediatric dentistry that were evaluated by at least 5 observational studies; (3) abstracting from these studies any data indicated by applying the reporting model; and (4) comparing available data elements to the desired data elements in the reporting model. The reporting model included data elements related to: (1) patients; (2) providers; (3) treatment details; and (4) study design. Two treatment comparisons in pediatric dentistry were identified with 5 or more observational studies: (1) stainless steel crowns vs amalgams (10 studies); and (2) composite restorations vs amalgam (5 studies). Results from studies comparing the same treatments varied substantially. Data elements from the reporting model that could have explained some of the variation were often reported inadequately or not at all. Reporting of observational studies in the pediatric dental literature may be inadequate for an informed interpretation of the results. Models similar to that used in this study could be used for developing standards for the conduct and reporting of observational studies in pediatric dentistry.

Heavier drinking American college students may self-select into study abroad programs: An examination of sex and ethnic differences within a high-risk group.

PubMed

Pedersen, Eric R; LaBrie, Joseph W; Hummer, Justin F; Larimer, Mary E; Lee, Christine M

2010-09-01

As with other heavier drinking groups, heavier drinking American college students may self-select into study abroad programs with specific intentions to use alcohol in the foreign environment. This cross-sectional study used a sample of 2144 students (mean age=20.00, SD=1.47) to explore differences in alcohol use and related negative consequences among (1) students intending to study abroad while in college, (2) students not intending to study abroad, and (3) students reporting prior study abroad participation. Results revealed that participants with no intention to study abroad drank less and experienced fewer alcohol-related consequences than participants intending to study abroad. In addition, students reporting prior completion of study abroad programs drank more and reported more hazardous alcohol use than those not intending to study abroad. Ethnic and sex differences existed; with White students, males, and females intending to study abroad and non-White students who previously completed study abroad programs demonstrating the most risk. These findings provide empirical support that study abroad students may be a heavier drinking subgroup necessitating intervention prior to beginning programs abroad. Copyright 2010 Elsevier Ltd. All rights reserved.

Heavier drinking American college students may self-select into study abroad programs: An examination of sex and ethnic differences within a high-risk group

PubMed Central

Pedersen, Eric R.; LaBrie, Joseph W.; Hummer, Justin F.; Larimer, Mary E.; Lee, Christine M.

2010-01-01

As with other heavier drinking groups, heavier drinking American college students may self-select into study abroad programs with specific intentions to use alcohol in the foreign environment. This cross-sectional study used a sample of 2144 students (mean age = 20.00, SD = 1.47) to explore differences in alcohol use and related negative consequences among (1) students intending to study abroad while in college, (2) students not intending to study abroad, and (3) students reporting prior study abroad participation. Results revealed that participants with no intention to study abroad drank less and experienced fewer alcohol-related consequences than participants intending to study abroad. In addition, students reporting prior completion of study abroad programs drank more and reported more hazardous alcohol use than those not intending to study abroad. Ethnic and sex differences existed; with White students, males, and females intending to study abroad and non-White students who previously completed study abroad programs demonstrating the most risk. These findings provide empirical support that study abroad students may be a heavier drinking subgroup necessitating intervention prior to beginning programs abroad. PMID:20510524

Current status of evidence-based sports medicine.

PubMed

Harris, Joshua D; Cvetanovich, Gregory; Erickson, Brandon J; Abrams, Geoffrey D; Chahal, Jaskarndip; Gupta, Anil K; McCormick, Frank M; Bach, Bernard R

2014-03-01

The purpose of this investigation is to determine the proportion of sports medicine studies that are labeled as Level I Evidence in 5 journals and compare the quality of surgical and nonsurgical studies using simple quality assessment tools (Consolidated Standards of Reporting Trials [CONSORT] and Jadad). By use of PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines over the prior 2 years in the top 5 (citation and impact factor based) sports medicine journals, only Level I Evidence studies were eligible for inclusion and were analyzed. All study types (therapeutic, prognostic, diagnostic, and economic) were analyzed. Study quality was assessed with the level of evidence, Jadad score, and CONSORT 2010 guidelines. Study demographic data were compared among journals and between surgical and nonsurgical studies by use of χ(2), 1-way analysis of variance, and 2-sample Z tests. We analyzed 190 Level I Evidence studies (10% of eligible studies) (119 randomized controlled trials [RCTs]). Therapeutic, nonsurgical, single-center studies from the United States were the most common studies published. Sixty-two percent of studies reported a financial conflict of interest. The knee was the most common body part studied, and track-and-field/endurance sports were the most common sports analyzed. Significant differences (P < .05) were shown in Jadad and CONSORT scores among the journals reviewed. Overall, the Jadad and CONSORT scores were 2.71 and 77%, respectively. No differences (P > .05) were shown among journals based on the proportion of Level I studies or appropriate randomization. Significant strengths and limitations of RCTs were identified. This study showed that Level I Evidence and RCTs comprise 10% and 6% of contemporary sports medicine literature, respectively. Therapeutic, nonsurgical, single-center studies are the most common publications with Level I Evidence. Significant differences across sports medicine journals were found in study quality. Surgical studies appropriately described randomization, blinding, and patient enrollment significantly more than nonsurgical studies. Level I, systematic review of Level I studies. Copyright © 2014 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Space station human productivity study. Volume 5: Management plans

NASA Technical Reports Server (NTRS)

1985-01-01

The 67 Management Plans represent recommended study approaches for resolving 108 of the 305 Issues which were identified. Each study Management Plan is prepared in three formats: Management Plan Overview (lists the subsumed Issues, study background, and related overview information); Study Plan (details the study approach by tasks, lists special needs, and describes expected study products); Schedule-Task Flow (provides a time-lined schedule for the study tasks and resource requirements). The Management Relationships Matrix, included in this volume, shows the data input-output relationships among all recommended studies. A listing is also included which cross-references the unresolved requirements to Issues to management plans. A glossary of all abbreviations utilized is provided.

Enhancing the quality of case studies in health services research.

PubMed Central

Yin, R K

1999-01-01

OBJECTIVE: To provide guidance on improving the quality of case studies in health services research. DATA SOURCES: Secondary data, drawing from previous case study research. RESEARCH DESIGN: Guidance is provided to two audiences: potential case study investigators (eight items) and reviewers of case study proposals (four additional items). PRINCIPAL FINDINGS: The guidance demonstrates that many operational steps can be undertaken to improve the quality of case studies. These steps have been a hallmark of high-quality case studies in related fields but have not necessarily been practiced in health services research. CONCLUSIONS: Given higher-quality case studies, the case study method can become a valuable tool for health services research. Images Figure 3 PMID:10591280

Maldi-tof fingerprinting of seminal plasma lipids in the study of human male infertility.

PubMed

Camargo, Mariana; Intasqui, Paula; de Lima, Camila Bruna; Montani, Daniela Antunes; Nichi, Marcílio; Pilau, Eduardo Jorge; Gozzo, Fabio Cesar; Lo Turco, Edson Guimarães; Bertolla, Ricardo Pimenta

2014-09-01

This study proposed lipid fingerprinting of human seminal plasma by mass spectrometry as an analytical method to differentiate biological conditions. For this purpose, we chose infertile men as a model to study specific conditions, namely: high and low seminal plasma lipid peroxidation levels (sub-study 1.1), high and low sperm nuclear DNA fragmentation (sub-study 1.2), and intervention status: before and after subinguinal microsurgical varicocelectomy (study 2). Study 1 included 133 patients, of which 113 were utilized for sub-study 1.1 and 89 for sub-study 1.2. Study 2 included 17 adult men submitted to subinguinal varicocelectomy, before and 90 days after varicocelectomy. Lipids were extracted from seminal plasma and submitted to Matrix-Assisted Laser Desorption Ionization Quadrupole-Time-of-Flight Mass Spectrometry in the positive ionization mode. Spectra were processed using Waters(®) MassLynx, and MetaboAnalyst online software was used for statistical analyses. For sub-studies 1.1 and 1.2, and study 2, univariate analysis revealed 8, 87 and 34 significant ions, respectively. Multivariate analysis was performed through PCA and PLS-DA. PCA generated 56, 32 and 34 components respectively for each study and these were submitted to logistic regression. A ROC curve was plotted and the area under the curve was equal to 97.4, 92.5 and 96.5%. PLS-DA generated a list of 19, 24 and 23 VIP ions for sub-studies 1.1 and 1.2, and study 2, respectively. Therefore, this study established the lipid profile and comparison of patterns altered in response to specific biological conditions.

Top 100 cited articles on epilepsy and status epilepticus: A bibliometric analysis.

PubMed

Park, Kang Min; Kim, Sung Eun; Lee, Byung In; Kim, Hyung Chan; Yoon, Dae Young; Song, Hong Ki; Bae, Jong Seok

2017-08-01

The purpose of this study is to identify the top 100-cited articles dedicated to epilepsy and status epilepticus published in journals from January, 1950 through February, 2016 that have made key contributions in the field. We performed a search of journals and selected the top 100-cited articles on epilepsy and status epilepticus, respectively, by utilizing the Institute for Scientific Information database available under the banner of the Web of Science. The top-cited articles on epilepsy and status epilepticus were all published in 24 journals, respectively. In both fields of epilepsy and status epilepticus, the most frequently cited journal was Epilepsia (26 articles on epilepsy and 19 articles on status epilepticus). The 100 most-cited articles in the field of both epilepsy and status epilepticus mainly originated from institutions in the United States of America. The articles on epilepsy included 25 laboratory studies, 15 pharmacotherapy studies, 13 general review studies, 12 surgery studies, 11 neuroimaging studies, eight epidemiology studies, eight neuropsychiatry studies, six genetic studies, and two electrophysiology studies, whereas 41 laboratory studies, 21 epidemiology studies, 16 pharmacotherapy studies, nine electrophysiology studies, nine general review studies, and four neuroimaging studies were included in the field of status epilepticus. We demonstrate that neuroimaging, genetics, and surgery are emerging topics in the field of epilepsy over the past decades. Moreover, we found that the majority of top-cited articles on epilepsy and status epilepticus originated from institutions in the United States of America and most were published in Epilepsia. Copyright © 2017 Elsevier Ltd. All rights reserved.

Extended cooperation in clinical studies through exchange of CDISC metadata between different study software solutions.

PubMed

Kuchinke, W; Wiegelmann, S; Verplancke, P; Ohmann, C

2006-01-01

Our objectives were to analyze the possibility of an exchange of an entire clinical study between two different and independent study software solutions. The question addressed was whether a software-independent transfer of study metadata can be performed without programming efforts and with software routinely used for clinical research. Study metadata was transferred with ODM standard (CDISC). Study software systems employed were MACRO (InferMed) and XTrial (XClinical). For the Proof of Concept, a test study was created with MACRO and exported as ODM. For modification and validation of the ODM export file XML-Spy (Altova) and ODM-Checker (XML4Pharma) were used. Through exchange of a complete clinical study between two different study software solutions, a Proof of Concept of the technical feasibility of a system-independent metadata exchange was conducted successfully. The interchange of study metadata between two different systems at different centers was performed with minimal expenditure. A small number of mistakes had to be corrected in order to generate a syntactically correct ODM file and a "vendor extension" had to be inserted. After these modifications, XTrial exhibited the study, including all data fields, correctly. However, the optical appearance of both CRFs (case report forms) was different. ODM can be used as an exchange format for clinical studies between different study software. Thus, new forms of cooperation through exchange of metadata seem possible, for example the joint creation of electronic study protocols or CRFs at different research centers. Although the ODM standard represents a clinical study completely, it contains no information about the representation of data fields in CRFs.

The Misconception of Case-Control Studies in the Plastic Surgery Literature: A Literature Audit.

PubMed

Hatchell, Alexandra C; Farrokhyar, Forough; Choi, Matthew

2017-06-01

Case-control study designs are commonly used. However, many published case-control studies are not true case-controls and are in fact mislabeled. The purpose of this study was to identify all case-control studies published in the top three plastic surgery journals over the past 10 years, assess which were truly case-control studies, clarify the actual design of the articles, and address common misconceptions. MEDLINE, Embase, and Web of Science databases were searched for case-control studies in the three highest-impact factor plastic surgery journals (2005 to 2015). Two independent reviewers screened the resulting titles, abstracts, and methods, if applicable, to identify articles labeled as case-control studies. These articles were appraised and classified as true case-control studies or non-case-control studies. The authors found 28 articles labeled as case-control studies. However, only six of these articles (21 percent) were truly case-control designs. Of the 22 incorrectly labeled studies, one (5 percent) was a randomized controlled trial, three (14 percent) were nonrandomized trials, two (9 percent) were prospective comparative cohort designs, 14 (64 percent) were retrospective comparative cohort designs, and two (9 percent) were cross-sectional designs. The mislabeling was worse in recent years, despite increases in evidence-based medicine awareness. The majority of published case-control studies are not in fact case-control studies. This misunderstanding is worsening with time. Most of these studies are actually comparative cohort designs. However, some studies are truly clinical trials and thus a higher level of evidence than originally proposed.

The relationship between urban environment and the inflammatory bowel diseases: a systematic review and meta-analysis.

PubMed

Soon, Ing Shian; Molodecky, Natalie A; Rabi, Doreen M; Ghali, William A; Barkema, Herman W; Kaplan, Gilaad G

2012-05-24

The objective of this study was to conduct a systematic review with meta-analysis of studies assessing the association between living in an urban environment and the development of the Crohn's disease (CD) or ulcerative colitis (UC). A systematic literature search of MEDLINE (1950-Oct. 2009) and EMBASE (1980-Oct. 2009) was conducted to identify studies investigating the relationship between urban environment and IBD. Cohort and case-control studies were analyzed using incidence rate ratio (IRR) or odds ratio (OR) with 95 % confidence intervals (CIs), respectively. Stratified and sensitivity analyses were performed to explore heterogeneity between studies and assess effects of study quality. The search strategy retrieved 6940 unique citations and 40 studies were selected for inclusion. Of these, 25 investigated the relationship between urban environment and UC and 30 investigated this relationship with CD. Included in our analysis were 7 case-control UC studies, 9 case-control CD studies, 18 cohort UC studies and 21 cohort CD studies. Based on a random effects model, the pooled IRRs for urban compared to rural environment for UC and CD studies were 1.17 (1.03, 1.32) and 1.42 (1.26, 1.60), respectively. These associations persisted across multiple stratified and sensitivity analyses exploring clinical and study quality factors. Heterogeneity was observed in the cohort studies for both UC and CD, whereas statistically significant heterogeneity was not observed for the case-control studies. A positive association between urban environment and both CD and UC was found. Heterogeneity may be explained by differences in study design and quality factors.

Mineral Resources of the Black Mountains North and Burns Spring Wilderness Study Areas, Mohave County, Arizona

USGS Publications Warehouse

Conrad, James E.; Hill, Randall H.; Jachens, Robert C.; Neubert, John T.

1990-01-01

At the request of the U.S. Bureau of Land Management, approximately 19,300 acres of the Black Mountains North Wilderness Study Area (AZ-020-009) and 23,310 acres of the Burns Spring Wilderness Study Area (AZ-02D-010) were evaluated for mineral resources and mineral resource potential. In this report, the area studied is referred to, collectively or individually, as the 'wilderness study area' or simply 'the study area'; any reference to the Black Mountains North or Burns Spring Wilderness Study Areas refers only to that part of the wilderness study area for which a mineral survey was requested by the U.S. Bureau of Land Management. The study area is located in western Arizona, about 30 mi northwest of Kingman. There are no identified resources in the study area. An area surrounding the Portland mine and including the southern part of the Black Mountains North Wilderness Study Area and the extreme northwestern part of the Burns Spring Wilderness Study Area has high resource potential for gold and moderate resource potential for silver, lead, and mercury. The area surrounding this and including much of the northern part of the Burns Spring Wilderness Study Area has moderate potential for gold, silver, and lead. The northeastern corner of the Black Mountains North Wilderness Study Area has moderate potential for gold and low potential for silver, copper, and molybdenum resources. The central part, including the narrow strip of land just west of the central part, of the Black Mountains North Wilderness Study Area and the southern and extreme eastern parts of the Burns Spring Wilderness Study Area have low resource potential for gold. The central and southern parts of the Black Mountains North Wilderness Study Area and all but the southwestern part of the Burns Spring Wilderness Study Area have moderate resource potential for perlite. Moderate resource potential for zeolites is assigned to a large area around the Portland mine that includes parts of both study areas, to a narrow strip of land just west of the central part of the Black Mountains North Wilderness Study Area, and to all but the southwest corner of the Burns Spring Wilderness Study Area. There is no potential for oil and gas in either study area. Sand and gravel are present in both study areas, but abundant quantities of these resources are available closer to existing markets.

An Examination of University Conducting Faculty Members' Score Study Attitudes and Practices

ERIC Educational Resources Information Center

Silvey, Brian A.; Springer, D. Gregory; Eubanks, Stephen C.

2016-01-01

The purpose of this study was to examine university conducting teachers' attitudes about score study, the source materials they used to teach score study, their personal score study practices, and the score study approaches they taught their undergraduate conducting students. Respondents (N = 236) were members of the College Band Directors…

A Study on the Spatial Abilities of Prospective Social Studies Teachers: A Mixed Method Research

ERIC Educational Resources Information Center

Yurt, Eyüp; Tünkler, Vural

2016-01-01

This study investigated prospective social studies teachers' spatial abilities. It was conducted with 234 prospective teachers attending Social Studies Teaching departments at Education Faculties of two universities in Central and Southern Anatolia. This study, designed according to the explanatory-sequential design, is a mixed research method,…

Korean University Students' Attitudes and Motivation towards Studying English

ERIC Educational Resources Information Center

Geddes, Aaron J.

2016-01-01

The main objective of this study was to identify the attitudes of Korean university students towards studying English and to determine if attending after-school English academies has had a negative impact on their attitudes towards studying English. The study also sought to determine if studying English leads to anxiety, and more importantly if…

41 CFR 101-30.701-1 - Item reduction study.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 2 2011-07-01 2007-07-01 true Item reduction study. 101....7-Item Reduction Program § 101-30.701-1 Item reduction study. Item reduction study means the study... so identified, a replacement item shall be proposed. The result of item reduction studies will...

41 CFR 101-30.701-1 - Item reduction study.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Item reduction study. 101....7-Item Reduction Program § 101-30.701-1 Item reduction study. Item reduction study means the study... so identified, a replacement item shall be proposed. The result of item reduction studies will...

University Students' Study Orientations, Learning Experiences and Study Success in Innovative Courses

ERIC Educational Resources Information Center

Honkimaki, Sanna; Tynjala, Paivi; Valkonen, Sakari

2004-01-01

The aim of this study was to find out whether university students' study orientations on four innovative courses differed from their usual orientations to their studies. Furthermore, students' study success and learning experiences were examined. The pedagogical innovations carried out on the courses included different kinds of activating…

[A Critical Condition of Clinical Studies in Japan -- A Battle of Clinical Study Groups].

PubMed

Furukawa, Hiroshi

2016-04-01

The post-marketing clinical study groups have been losing their activity due to stop of financial support. As the result, clinical study groups cannot achieve any EBM for treatment guidelines. Financial supports should be restarted immediately not to extinguish the post-marketing clinical studies and study groups.

Gender Issues in the Implementation of Social Studies Curriculum in Nigerian Universities

ERIC Educational Resources Information Center

Mezieobi, Dan I.; Oyeoku, E. K.; Ezegbe, B. N.; Igbo, Janeth

2012-01-01

The study investigated gender issues in the implementation of social studies curriculum in Nigerian universities. The subjects for the study comprised of all the 200 final-year sandwich social studies students of University of Port-Harcourt in the 2009 contact session. Five research questions guided the study. Researchers developed questionnaire…

Assessing Statistical Change Indices in Selected Social Work Intervention Research Studies

ERIC Educational Resources Information Center

Ham, Amanda D.; Huggins-Hoyt, Kimberly Y.; Pettus, Joelle

2016-01-01

Objectives: This study examined how evaluation and intervention research (IR) studies assessed statistical change to ascertain effectiveness. Methods: Studies from six core social work journals (2009-2013) were reviewed (N = 1,380). Fifty-two evaluation (n= 27) and intervention (n = 25) studies met the inclusion criteria. These studies were…

Social Studies--The Next Generation: Re-Searching in the Postmodern. Counterpoints, Studies in the Postmodern Theory of Education Volume 272

ERIC Educational Resources Information Center

Segall, Avner, Ed.; Heilman, Elizabeth E., Ed.; Cherryholmes, Cleo H., Ed.

2006-01-01

This book broadens the imagination within social studies education by highlighting current, cutting-edge scholarship incorporating critical discourses. Drawing on postmodern, poststructural, postcolonial, and feminist theories often borrowed from cultural studies, curriculum theory, critical geography, women's studies, and queer studies, the…

Female Islamic Studies Teachers in Saudi Arabia: A Phenomenological Study

ERIC Educational Resources Information Center

Jamjoom, Mounira I.

2010-01-01

This study highlights on describing the experiences of Saudi Arabian female Islamic Studies teachers by exploring what is means to be an Islamic Studies teacher teaching in the current unprecedented vibrant and complex tapestry of social, religious and political debates occurring in the larger context of the country. The study draws on…

Study Abroad Survey Instruments: A Comparison of Survey Types and Experiences

ERIC Educational Resources Information Center

Durrant, Marie Bradshaw; Dorius, Cassandra Rasmussen

2007-01-01

This study examines different survey instruments used to assess the experiences of U.S. study abroad participants. The intended audience is international and area study practitioners interested in assessing study abroad programs through postprogram interviews. An interview with the top 20 universities for number of students sent on study abroad…

Social Studies Doctoral Dissertations in the United States and Turkey: A Comparative Study

ERIC Educational Resources Information Center

Savas, Behsat

2016-01-01

This study delves into 169 social studies doctoral dissertations published from January 2012 to October 2015. The results of the included studies were qualitatively synthesized and presented in narrative form in the results section. In preliminary searching for systematic reviews concerning social studies, we concentrated on 169 doctoral…

Relationship between Study Habits and Test Anxiety of Higher Secondary Students

ERIC Educational Resources Information Center

Lawrence, Arul A. S.

2014-01-01

The present study aims to probe the relationship between study habits and test anxiety of higher secondary students. In this normative study survey method was employed. The population for the present study consisted of higher secondary students studying in Tirunelveli district. The investigator used the simple random sampling technique. The sample…

Conceptualizing Agency: Preservice Social Studies Teachers' Thinking about Professional Decisions

ERIC Educational Resources Information Center

Clark, J. Spencer

2011-01-01

This qualitative study investigated preservice social studies teachers' thinking about personal agency. This study used a case study design and was conducted in a semester long undergraduate social studies methods course. The findings drew upon data from eight participants. The participants were selected based on their stated purpose for teaching…

Teacher Characteristics as Correlates of Students Achievement in Social Studies: A Case Study in Nigeria

ERIC Educational Resources Information Center

Enwelim, Samuel Chiedu

2016-01-01

The study on teacher characteristics and students achievement in social Studies in Nigeria is geared towards investigating and determining the relationship between teachers' characteristics and students achievement in social studies in Nigeria. The main purpose of the study is to determine if there is relationship between certain teacher…

Behavior Modification of Studying Through Study Skills Advice and Self-Control Procedures

ERIC Educational Resources Information Center

Richards, C. Steven

1975-01-01

Investigates the efficacy of two behavioral self-control procedures as additions to the typical treatment for college students' study behavior--study skills advice. Predicted self-monitoring would be an effective treatment addition to study skills advice and study skills advice would be superior to the control groups. Results supported…

Science and Social Studies Teachers' Beliefs and Practices about Teaching Controversial Issues: Certain Comparisons

ERIC Educational Resources Information Center

Kus, Zafer

2015-01-01

The current study aims to investigate social studies and science teachers' attitudes and classroom practices associated with controversial issues. The study is a qualitative research based on data collected through interviews and observation. Social studies and Science teachers participated in the current study which was conducted in Kirsehir, a…

How to Study a Matrix

ERIC Educational Resources Information Center

Jairam, Dharmananda; Kiewra, Kenneth A.; Kauffman, Douglas F.; Zhao, Ruomeng

2012-01-01

This study investigated how best to study a matrix. Fifty-three participants studied a matrix topically (1 column at a time), categorically (1 row at a time), or in a unified way (all at once). Results revealed that categorical and unified study produced higher: (a) performance on relationship and fact tests, (b) study material satisfaction, and…

An Analysis of the Quality Assurance Policies in a Ghanian University

ERIC Educational Resources Information Center

Seniwoliba, Joseph Attiah; Yakubu, Richard Nalarb

2015-01-01

The study examined the implementation challenges of quality assurance in public universities in Ghana with a focus on University for Development Studies (UDS). The study adopted a qualitative case study design. The data for the study was collected through in-depth interviews, document analysis and participants observation. The study revealed that…

Studying for Success: Diaries of Students' Study Behaviours

ERIC Educational Resources Information Center

Tomes, Jennifer L.; Wasylkiw, Louise; Mockler, Brittany

2011-01-01

The current study examined students' study behaviours using a diary methodology. Given the limitations of previous investigations, participants were asked to complete daily study diaries for 10 days prior to a course test to assess students' actual study behaviours. Results showed that students engaged in a diverse set of behaviours with only some…

Baccalaureate Student Nurses' Study Habits Prior to Admission to Nursing Program: A Descriptive Qualitative Study.

PubMed

Felicilda-Reynaldo, Rhea Faye D; Cruz, Jonas Preposi; Bigley, Louise; Adams, Kathryn

2017-06-01

Faculty continue to observe students struggling as they adapt their study strategies to learn nursing core content. This study described the study habits of Bachelor of Science in Nursing (BSN) students prior to admission to the program. This study used a descriptive qualitative research design. A purposive sample of 19 BSN students (juniors [n=10] and seniors [n=9]) from a 4-year public Midwestern university were included in this study. Two focus group sessions, using a semi-structured interview guide, were conducted in the spring semester of 2013. The four themes which emerged from the analysis of data were: "I just got it," "I had a lot of time then," "I studied alone" mostly, and "…a little struggle with the sciences." The findings suggest the BSN students did not study much or employed poor study strategies during their years completing general education courses. Academic support is needed by students prior to admission to the nursing program so they can learn effective study skills and modify their study habits for easier adaptation to the rigors of nursing education. Published by Elsevier Ltd.

An In Vivo Study of Self-Regulated Study Sequencing in Introductory Psychology Courses

PubMed Central

de Leeuw, Joshua R.; Motz, Benjamin A.; Goldstone, Robert L.

2016-01-01

Study sequence can have a profound influence on learning. In this study we investigated how students decide to sequence their study in a naturalistic context and whether their choices result in improved learning. In the study reported here, 2061 undergraduate students enrolled in an Introductory Psychology course completed an online homework tutorial on measures of central tendency, a topic relevant to an exam that counted towards their grades. One group of students was enabled to choose their own study sequence during the tutorial (Self-Regulated group), while the other group of students studied the same materials in sequences chosen by other students (Yoked group). Students who chose their sequence of study showed a clear tendency to block their study by concept, and this tendency was positively associated with subsequent exam performance. In the Yoked group, study sequence had no effect on exam performance. These results suggest that despite findings that blocked study is maladaptive when assigned by an experimenter, it may actually be adaptive when chosen by the learner in a naturalistic context. PMID:27003164

An In Vivo Study of Self-Regulated Study Sequencing in Introductory Psychology Courses.

PubMed

Carvalho, Paulo F; Braithwaite, David W; de Leeuw, Joshua R; Motz, Benjamin A; Goldstone, Robert L

2016-01-01

Study sequence can have a profound influence on learning. In this study we investigated how students decide to sequence their study in a naturalistic context and whether their choices result in improved learning. In the study reported here, 2061 undergraduate students enrolled in an Introductory Psychology course completed an online homework tutorial on measures of central tendency, a topic relevant to an exam that counted towards their grades. One group of students was enabled to choose their own study sequence during the tutorial (Self-Regulated group), while the other group of students studied the same materials in sequences chosen by other students (Yoked group). Students who chose their sequence of study showed a clear tendency to block their study by concept, and this tendency was positively associated with subsequent exam performance. In the Yoked group, study sequence had no effect on exam performance. These results suggest that despite findings that blocked study is maladaptive when assigned by an experimenter, it may actually be adaptive when chosen by the learner in a naturalistic context.

The fate of prospective spine studies registered on www.ClinicalTrials.gov.

PubMed

Ohnmeiss, Donna D

2015-03-01

There has been concern expressed about research ethics with respect to not fully reporting data collected during clinical studies. One site available for all clinical trials is ClinicalTrials.gov. The original purpose of this site was to facilitate patients seeking a trial for the treatment of their particular condition. The internationally available site offers general information about the study, sponsor name, principal investigator, patient selection criteria, enrollment goal, study design, outcome measures, participating centers, initiation date, date posted, date completed, and other pertinent data. The site can be used to identify studies conducted for a particular condition or intervention. The purpose of this study was to investigate the fate of spine-related studies registered on www.ClinicalTrials.gov, with particular focus on the publication rate of completed trials. Analysis and classification of clinical studies posted on an international research registry Web page and literature search for related publications. Not applicable. The primary outcome measure was publication of the study registered on ClinicalTrials.gov. Multiple searches were conducted on ClinicalTrials.gov Web site to identify studies related to commonly treated spinal conditions, including herniated disc, degenerative disc disease, stenosis, and spondylolisthesis. Studies related to tumors, fractures, or that included nonspine conditions were not included. For studies classified as completed more than 18 months before this review, literature searches were conducted to determine if the results of the study had been published and factors related to publication. The author has no financial conflict related to this work. There were 263 spine-related studies identified from searches on the ClinicalTrials.gov site. Data on the site had the studies classified as follows: 72 completed, 70 active, not recruiting (generally indicates collecting follow-up data), 74 recruiting, 11 recruiting by invitation, 13 not yet recruiting, 18 terminated, 4 withdrawn, and 1 suspended. Among the 72 studies indicated to be completed, 28 (38.9%) have been published. The mean time to publish was 27.9 months from the date of completion. Among unpublished studies, the mean length of time from study completion to the preparation of this article was 62.0 months. There was no difference in the likelihood of publication based on the geographic region of study origin or whether the study was registered before or after initiation. There were statistically significant relationships between the publication rate and the funding type as well as the research type (p<.05) with industrial-funded studies and those evaluating devices having a lower publication rate and those that were funded by a federal agency and comparing surgery to nonoperative care had the highest publication rates. Although the 38.9% publication rate for spine-related studies found in this study appears low, it is in line with other studies reporting a 22.8% publication rate for arthroplasty trials and 43.2% for orthopedic trauma trials. In addition to ClinicalTrials.gov Web site fulfilling its original goal of providing patients information about clinical studies, it can also provide a means of tracking publication of prospective studies, changes to protocols, matching publication content to posted study design, and others and raise queries concerning the reasons for not publishing what appear to be well-designed studies. The posting of spine studies before initiation can increase transparency and ability to evaluate clinical trials in spine. Copyright © 2015 Elsevier Inc. All rights reserved.

Larvivorous fish for preventing malaria transmission

PubMed Central

Walshe, Deirdre P; Garner, Paul; Adeel, Ahmed A; Pyke, Graham H; Burkot, Thomas R

2017-01-01

Background Adult female Anopheles mosquitoes can transmit Plasmodium parasites that cause malaria. Some fish species eat mosquito larvae and pupae. In disease control policy documents, the World Health Organization (WHO) includes biological control of malaria vectors by stocking ponds, rivers, and water collections near where people live with larvivorous fish to reduce Plasmodium parasite transmission. In the past, the Global Fund has financed larvivorous fish programmes in some countries, and, with increasing efforts in eradication of malaria, policymakers may return to this option. Therefore, we assessed the evidence base for larvivorous fish programmes in malaria control. Objectives To evaluate whether introducing larvivorous fish to anopheline larval habitats impacts Plasmodium parasite transmission. We also sought to summarize studies that evaluated whether introducing larvivorous fish influences the density and presence of Anopheles larvae and pupae in water sources. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; MEDLINE (PubMed); Embase (Ovid); CABS Abstracts; LILACS; and the metaRegister of Controlled Trials (mRCT) up to 6 July 2017. We checked the reference lists of all studies identified by the search. We examined references listed in review articles and previously compiled bibliographies to look for eligible studies. Also we contacted researchers in the field and the authors of studies that met the inclusion criteria for additional information regarding potential studies for inclusion and ongoing studies. This is an update of a Cochrane Review published in 2013. Selection criteria Randomized controlled trials (RCTs) and non-RCTs, including controlled before-and-after studies, controlled time series, and controlled interrupted time series studies from malaria-endemic regions that introduced fish as a larvicide and reported on malaria in the community or the density of the adult anopheline population. In the absence of direct evidence of an effect on transmission, we performed a secondary analysis on studies that evaluated the effect of introducing larvivorous fish on the density or presence of immature anopheline mosquitoes (larvae and pupae forms) in water sources to determine whether this intervention has any potential that may justify further research in the control of malaria vectors. Data collection and analysis Two review authors independently screened each article by title and abstract, and examined potentially relevant studies for inclusion using an eligibility form. At least two review authors independently extracted data and assessed risk of bias of included studies. If relevant data were unclear or were not reported, we contacted the study authors for clarification. We presented data in tables, and we summarized studies that evaluated the effects of introducing fish on anopheline immature density or presence, or both. We used the GRADE approach to summarize the certainty of the evidence. We also examined whether the included studies reported any possible adverse impact of introducing larvivorous fish on non-target native species. Main results We identified no studies that reported the effects of introducing larvivorous fish on the primary outcomes of this review: malaria infection in nearby communities, entomological inoculation rate, or on adult Anopheles density. For the secondary analysis, we examined the effects of introducing larvivorous fish on the density and presence of anopheline larvae and pupae in community water sources, and found 15 small studies with a follow-up period between 22 days and five years. These studies were undertaken in Sri Lanka (two studies), India (three studies), Ethiopia (one study), Kenya (two studies), Sudan (one study), Grande Comore Island (one study), Korea (two studies), Indonesia (one study), and Tajikistan (two studies). These studies were conducted in a variety of settings, including localized water bodies (such as wells, domestic water containers, fishponds, and pools (seven studies); riverbed pools below dams (two studies)); rice field plots (five studies); and water canals (two studies). All included studies were at high risk of bias. The research was insufficient to determine whether larvivorous fish reduce the density of Anopheles larvae and pupae (12 studies, unpooled data, very low certainty evidence). Some studies with high stocking levels of fish seemed to arrest the increase in immature anopheline populations, or to reduce the number of immature anopheline mosquitoes, compared with controls. However, this finding was not consistent, and in studies that showed a decrease in immature anopheline populations, the effect was not always consistently sustained. In contrast, some studies reported larvivorous fish reduced the number of water sources withAnopheles larvae and pupae (five studies, unpooled data, low certainty evidence). None of the included studies reported effects of larvivorous fish on local native fish populations or other species. Authors' conclusions We do not know whether introducing larvivorous fish reduces malaria transmission or the density of adult anopheline mosquito populations. In research studies that examined the effects on immature anopheline stages of introducing fish to potential malaria vector larval habitats, high stocking levels of fish may reduce the density or presence of immature anopheline mosquitoes in the short term. We do not know whether this translates into impact on malaria transmission. Our interpretation of the current evidence is that countries should not invest in fish stocking as a stand alone or supplementary larval control measure in any malaria transmission areas outside the context of research using carefully controlled field studies or quasi-experimental designs. Such research should examine the effects on native fish and other non-target species. Fish that feed on mosquito larvae for preventing malaria transmission What is the aim of this review? Adult female Anopheles mosquitoes transmit the Plasmodium parasites that cause malaria. The aim of this Cochrane Review was to evaluate whether introducing fish that eat mosquito larvae and pupae (early life stages of mosquitoes) into water sources near where people live will decrease the adult Anopheles mosquito population and thus the number of people infected with Plasmodium parasites. Key messages We do not know if introducing fish that eat mosquito larvae and pupae has an impact on the number of people with malaria or on the adult Anopheles mosquito population. What was studied in the review? The review authors examined the available research that evaluated introducing fish that eat larvae ('larvivorous') to Anopheles mosquito larval habitats in areas where malaria was common. Fifteen small studies looked at the effects of larvivorous fish on Anopheles larvae and pupae in different larval habitats, including localized water bodies (such as wells, domestic water containers, fishponds, and pools; seven studies), riverbed pools below dams (two studies), rice field plots (four studies), and water canals (two studies). These studies were undertaken in Sri Lanka (two studies), India (three studies), Ethiopia (one study), Kenya (two studies), Sudan (one study), Grande Comore Island (one study), Korea (two studies), Indonesia (one study), and Tajikistan (two studies). This is an update of a 2013 Cochrane Review and includes some older unpublished studies from Tajikistan and a new trial from India. What are the main results of the review? In our main analysis, we found no studies that looked at the effects of larvivorous fish on adult Anopheles mosquito populations or on the number of people infected with Plasmodium parasites. In our analysis exploring the effect of fish introduction on the number of Anopheles larvae and pupae in water collections, these studies produced inconsistent results on immature mosquito density (12 studies, unpooled data, very low certainty evidence). Some studies that measured the number of water sources withAnopheles larvae and pupae reported a reduction in the number of sites with Anopheles larvae and pupae after introducing fish (five studies, unpooled data, low certainty evidence). None of the included studies examined the effects of introducing larvivorous fish on other native species present, but these studies were not designed to do this. All included studies were at high risk of bias. Before much is invested in this intervention, we need better research to determine the effect of introducing larvivorous fish on the number of people infected with malaria, and on adult Anopheles populations. Researchers need to use robust controlled designs with an adequate number of sites. In addition, researchers should explore the potential harms from introducing these fish on native fish and other non-Anopheles species. How up-to-date is this review? The review authors searched for studies published up to 6 July 2017. PMID:29226959

Ecological baseline studies

NASA Technical Reports Server (NTRS)

Vickers, D.

1980-01-01

Environmental studies of Merritt Island are discussed. Five areas of the island's ecology are examined. They include: a terrestrial community analyses, a plant community study, a small mammal population study, a rainfall study, and an ichthyological analyses.

Do Studies Evaluating QT/QTc Interval Prolongation with Dietary Supplements Meet FDA Standards: A Systematic Review.

PubMed

Nguyen, Tinh An; Kurian, Amy; Leong, Jessica; Patel, Umang M; Shah, Sachin A

2017-07-04

Dietary supplement use is continuously increasing, but the safety evaluation of these products remains partial. While dietary supplements have no mandate for assessing cardiovascular safety, all new drug entities (NDE) are required to undergo a thorough QT/corrected QT (QTc) assessment to determine their propensity to impact cardiac repolarization. Independent investigators and manufacturers of dietary supplements voluntarily initiate safety studies; however, the quality of these studies is controversial. We sought to compare studies evaluating the QT/QTc effects of dietary supplements based on the International Conference of Harmonization (ICH)-E14 recommendations for NDE. Twenty-six published dietary supplement studies assessed QT/QTc interval prolongation. Sample sizes ranged from nine subjects to 206 among the 15 crossover studies, six parallel design studies, and five observational studies. A plan to account for electrocardiogram (ECG) morphological abnormalities was included in 10 studies, and two studies reported cardiovascular adverse events. Eight studies found a significant change in QT/QTc intervals. The majority of studies included in this review contained many of the critical elements recommended by the ICH E14, which includes the U.S. Food and Drug Administration guidance document for QT/QTc interval assessment. Compared with the thorough QT (TQT) standards, studies are typically well performed but can be bolstered by some study design changes. More than 30% of the included studies showed some degree of ECG changes, suggesting the need for continued cardiovascular safety assessment of dietary supplements.

A traits-based approach for prioritizing species for monitoring and surrogacy selection

DOE PAGES

Pracheil, Brenda M.; McManamay, Ryan A.; Bevelhimer, Mark S.; ...

2016-11-28

The bar for justifying the use of vertebrate animals for study is being increasingly raised, thus requiring increased rigor for species selection and study design. Although we have power analyses to provide quantitative backing for the numbers of organisms used, quantitative backing for selection of study species is not frequently employed. This can be especially important when measuring the impacts of ecosystem alteration, when study species must be chosen that are both sensitive to the alteration and of sufficient abundance for study. Just as important is providing justification for designation of surrogate species for study, especially when the species ofmore » interest is rare or of conservation concern and selection of an appropriate surrogate can have legal implications. In this study, we use a combination of GIS, a fish traits database and multivariate statistical analyses to quantitatively prioritize species for study and to determine potential study surrogate species. We provide two case studies to illustrate our quantitative, traits-based approach for designating study species and surrogate species. In the first case study, we select broadly representative fish species to understand the effects of turbine passage on adult fishes based on traits that suggest sensitivity to turbine passage. In our second case study, we present a framework for selecting a surrogate species for an endangered species. Lastly, we suggest that our traits-based framework can provide quantitative backing and added justification to selection of study species while expanding the inference space of study results.« less

Vitamin C Intake and Pancreatic Cancer Risk: A Meta-Analysis of Published Case-Control and Cohort Studies.

PubMed

Hua, Yong-Fei; Wang, Gao-Qing; Jiang, Wei; Huang, Jing; Chen, Guo-Chong; Lu, Cai-De

2016-01-01

Observational studies inconsistently reported the relationship between vitamin C intake and risk of pancreatic cancer. We conducted a meta-analysis of published case-control and cohort studies to quantify the association. Potentially eligible studies were found on PubMed and EMBASE databases through May 31, 2015. A random-effects model was assigned to compute summary point estimates with corresponding 95% confidence intervals (CIs). Subgroup and meta-regression analyses were also performed to explore sources of heterogeneity. Our final analyses included 20 observational studies comprising nearly 5 thousand cases of pancreatic cancer. When comparing the highest with the lowest categories of vitamin C intake, the summary odds ratio/relative risk for case-control studies (14 studies), cohort studies (6 studies) and all studies combined was 0.58 (95% CI: 0.52-0.66), 0.93 (95% CI: 0.78-1.11) and 0.66 (95% CI: 0.58-0.75), respectively. The difference in the findings between case-control and cohort studies was statistically significant (P < .001). Possible publication bias was shown in the meta-analysis of case-control studies. There is insufficient evidence to conclude any relationship between vitamin C intake and risk of pancreatic cancer. The strong inverse association observed in case-control studies may be affected by biases (eg, recall and selection biases) that particularly affect case-control studies and/or potential publication bias. Future prospective studies of vitamin C intake and pancreatic cancer are needed.

Eating for the better: a social marketing review (2000-2012).

PubMed

Carins, Julia E; Rundle-Thiele, Sharyn R

2014-07-01

The present study sought to identify both the ingredients for success and the potential impediments to social marketing effectiveness for healthy eating behaviour, focusing on studies conducted over the last 10 years. A comprehensive literature review was undertaken examining seventeen databases to identify studies reporting the use of social marketing to address healthy eating. Thirty-four empirical studies were analysed to examine the effectiveness of social marketing interventions to improve healthy eating behaviour using Andreasen's (2002) social marketing benchmark criteria. Statistical analysis was undertaken to quantitatively evaluate whether effectiveness varied between study categories (subsets). Healthy eating empirical studies published from 2000 onwards. Empirical studies that self-identified as social marketing. Sixteen social marketing studies (subset 1) were identified in the review. These were systematic studies which sought to change behaviour through tailored solutions (e.g. use of marketing tools beyond communication was clearly evident) that delivered value to the target audience. For these sixteen studies, the mean number of criteria identified was five. Six studies met all six criteria. Positive change to healthy eating behaviour was found in fourteen of sixteen studies. The sixteen studies that met the definition of social marketing used significantly more of Andreasen's (2002) criteria and were more effective in achieving behavioural change than the eighteen studies in subset 2. Social marketing is an involved process and it is important that studies identifying as social marketing adopt social marketing benchmark criteria. Social marketing when employed to its full extent offers the potential to change healthy eating.

Palliative Sedation in Advanced Cancer Patients: Does it Shorten Survival Time? - A Systematic Review

PubMed Central

Barathi, B; Chandra, Prabha S

2013-01-01

Background: Patients with advanced cancer often suffer from multiple refractory symptoms in the terminal phase of their life. Palliative sedation is one of the few ways to relieve this refractory suffering. Objectives: This systematic review investigated the effect of palliative sedation on survival time in terminally ill cancer patients. Materials and Methods: Six electronic databases were searched for both prospective and retrospective studies which evaluated the effect of palliative sedation on survival time. Only those studies which had a comparison group that did not receive palliative sedation were selected for the review. Abstracts of all retrieved studies were screened to include the most relevant studies and only studies which met inclusion criteria were selected. References of all retrieved studies were also screened for relevant studies. Selected studies were assessed for quality and data extraction was done using the structured data extraction form. Results: Eleven studies including four prospective and seven retrospective studies were identified. Mean survival time (MST) was measured as the time from last admission until death. A careful analysis of the results of all the 11 studies indicated that MST of sedated and non-sedated group was not statistically different in any of the studies. Conclusion: This systematic review supports the fact that palliative sedation does not shorten survival in terminally ill cancer patients. However, this conclusion needs to be taken with consideration of the methodology, study design, and the population studied of the included studies in this review. PMID:23766594

Palliative Sedation in Advanced Cancer Patients: Does it Shorten Survival Time? - A Systematic Review.

PubMed

Barathi, B; Chandra, Prabha S

2013-01-01

Patients with advanced cancer often suffer from multiple refractory symptoms in the terminal phase of their life. Palliative sedation is one of the few ways to relieve this refractory suffering. This systematic review investigated the effect of palliative sedation on survival time in terminally ill cancer patients. Six electronic databases were searched for both prospective and retrospective studies which evaluated the effect of palliative sedation on survival time. Only those studies which had a comparison group that did not receive palliative sedation were selected for the review. Abstracts of all retrieved studies were screened to include the most relevant studies and only studies which met inclusion criteria were selected. References of all retrieved studies were also screened for relevant studies. Selected studies were assessed for quality and data extraction was done using the structured data extraction form. Eleven studies including four prospective and seven retrospective studies were identified. Mean survival time (MST) was measured as the time from last admission until death. A careful analysis of the results of all the 11 studies indicated that MST of sedated and non-sedated group was not statistically different in any of the studies. This systematic review supports the fact that palliative sedation does not shorten survival in terminally ill cancer patients. However, this conclusion needs to be taken with consideration of the methodology, study design, and the population studied of the included studies in this review.

A traits-based approach for prioritizing species for monitoring and surrogacy selection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pracheil, Brenda M.; McManamay, Ryan A.; Bevelhimer, Mark S.

The bar for justifying the use of vertebrate animals for study is being increasingly raised, thus requiring increased rigor for species selection and study design. Although we have power analyses to provide quantitative backing for the numbers of organisms used, quantitative backing for selection of study species is not frequently employed. This can be especially important when measuring the impacts of ecosystem alteration, when study species must be chosen that are both sensitive to the alteration and of sufficient abundance for study. Just as important is providing justification for designation of surrogate species for study, especially when the species ofmore » interest is rare or of conservation concern and selection of an appropriate surrogate can have legal implications. In this study, we use a combination of GIS, a fish traits database and multivariate statistical analyses to quantitatively prioritize species for study and to determine potential study surrogate species. We provide two case studies to illustrate our quantitative, traits-based approach for designating study species and surrogate species. In the first case study, we select broadly representative fish species to understand the effects of turbine passage on adult fishes based on traits that suggest sensitivity to turbine passage. In our second case study, we present a framework for selecting a surrogate species for an endangered species. Lastly, we suggest that our traits-based framework can provide quantitative backing and added justification to selection of study species while expanding the inference space of study results.« less

Methodological and ethical challenges in studying patients' perceptions of coercion: a systematic mixed studies review.

PubMed

Soininen, Päivi; Putkonen, Hanna; Joffe, Grigori; Korkeila, Jyrki; Välimäki, Maritta

2014-06-04

Despite improvements in psychiatric inpatient care, patient restrictions in psychiatric hospitals are still in use. Studying perceptions among patients who have been secluded or physically restrained during their hospital stay is challenging. We sought to review the methodological and ethical challenges in qualitative and quantitative studies aiming to describe patients' perceptions of coercive measures, especially seclusion and physical restraints during their hospital stay. Systematic mixed studies review was the study method. Studies reporting patients' perceptions of coercive measures, especially seclusion and physical restraints during hospital stay were included. Methodological issues such as study design, data collection and recruitment process, participants, sampling, patient refusal or non-participation, and ethical issues such as informed consent process, and approval were synthesized systematically. Electronic searches of CINALH, MEDLINE, PsychINFO and The Cochrane Library (1976-2012) were carried out. Out of 846 initial citations, 32 studies were included, 14 qualitative and 18 quantitative studies. A variety of methodological approaches were used, although descriptive and explorative designs were used in most cases. Data were mainly collected in qualitative studies by interviews (n = 13) or in quantitative studies by self-report questionnaires (n = 12). The recruitment process was explained in 59% (n = 19) of the studies. In most cases convenience sampling was used, yet five studies used randomization. Patient's refusal or non-participation was reported in 37% (n = 11) of studies. Of all studies, 56% (n = 18) had reported undergone an ethical review process in an official board or committee. Respondents were informed and consent was requested in 69% studies (n = 22). The use of different study designs made comparison methodologically challenging. The timing of data collection (considering bias and confounding factors) and the reasons for non-participation of eligible participants are likewise methodological challenges, e.g. recommended flow charts could aid the information. Other challenges identified were the recruitment of large and representative samples. Ethical challenges included requesting participants' informed consent and respecting ethical procedures.

Postmarketing studies for novel drugs approved by both the FDA and EMA between 2005 and 2010: a cross-sectional study

PubMed Central

Zeitoun, Jean-David; Ross, Joseph S; Atal, Ignacio; Vivot, Alexandre; Downing, Nicholas S; Baron, Gabriel; Ravaud, Philippe

2017-01-01

Objectives To characterise postmarketing studies for drugs that were newly approved by the US Food and Drug Administration and the European Medicines Agency. Design and setting Cross-sectional analysis of postmarketing studies registered in ClinicalTrials.gov until September 2014 for all novel drugs approved by both regulators between 2005 and 2010. Regulatory documents from both agencies were used. Primary and secondary outcome measures All identified postmarketing studies were classified according to planned enrolment, funding, status and geographical location, and we determined whether studies studied the originally approved indication. Results Overall, 69 novel drugs approved between 2005 and 2010 were eligible for inclusion. A total of 6679 relevant postmarketing studies were identified; 5972 were interventional (89.4%). The median number of studies per drug was 55 (IQR 33–119) and median number of patients to be enrolled per study was 60 (IQR 28–183). Industry was the primary sponsor of 2713 studies (40.6%) and was a primary or secondary sponsor in 4176 studies (62.5%). In all, 2901 studies (43.4%) were completed, 487 (7.3%) terminated, 1013 (15.2%) active yet not recruiting, 1895 (28.4%) recruiting and 319 (4.8%) not yet recruiting. A total of 80% of studies were conducted in only one country and 84.4% took place in Europe and/or North America; 2441 (36.5%) studied another indication than the originally approved indication. Studies designed in the originally approved indication were found to be more industry-sponsored than others 68.7%vs53.7%; P<0.0001. Conclusions Postmarketing pharmaceutical research was highly variable and predominantly located in North America and Europe. Postmarketing studies were frequently designed to study indications other than the originally approved one. Although some findings were reassuring, others question the lack of coordination of postmarketing research. PMID:29273664

Why are medical and health-related studies not being published? A systematic review of reasons given by investigators.

PubMed

Song, Fujian; Loke, Yoon; Hooper, Lee

2014-01-01

About half of medical and health-related studies are not published. We conducted a systematic review of reports on reasons given by investigators for not publishing their studies in peer-reviewed journals. MEDLINE, EMBASE, PsycINFO, and SCOPUS (until 13/09/2013), and references of identified articles were searched to identify reports of surveys that provided data on reasons given by investigators for not publishing studies. The proportion of non-submission and reasons for non-publication was calculated using the number of unpublished studies as the denominator. Because of heterogeneity across studies, quantitative pooling was not conducted. Exploratory subgroup analyses were conducted. We included 54 survey reports. Data from 38 included reports were available to estimate proportions of at least one reason given for not publishing studies. The proportion of non-submission among unpublished studies ranged from 55% to 100%, with a median of 85%. The reasons given by investigators for not publishing their studies included: lack of time or low priority (median 33%), studies being incomplete (median 15%), study not for publication (median 14%), manuscript in preparation or under review (median 12%), unimportant or negative result (median 12%), poor study quality or design (median 11%), fear of rejection (median 12%), rejection by journals (median 6%), author or co-author problems (median 10%), and sponsor or funder problems (median 9%). In general, the frequency of reasons given for non-publication was not associated with the source of unpublished studies, study design, or time when a survey was conducted. Non-submission of studies for publication remains the main cause of non-publication of studies. Measures to reduce non-publication of studies and alternative models of research dissemination need to be developed to address the main reasons given by investigators for not publishing their studies, such as lack of time or low priority and fear of being rejected by journals.

Why Are Medical and Health-Related Studies Not Being Published? A Systematic Review of Reasons Given by Investigators

PubMed Central

Song, Fujian; Loke, Yoon; Hooper, Lee

2014-01-01

Objective About half of medical and health-related studies are not published. We conducted a systematic review of reports on reasons given by investigators for not publishing their studies in peer-reviewed journals. Methods MEDLINE, EMBASE, PsycINFO, and SCOPUS (until 13/09/2013), and references of identified articles were searched to identify reports of surveys that provided data on reasons given by investigators for not publishing studies. The proportion of non-submission and reasons for non-publication was calculated using the number of unpublished studies as the denominator. Because of heterogeneity across studies, quantitative pooling was not conducted. Exploratory subgroup analyses were conducted. Results We included 54 survey reports. Data from 38 included reports were available to estimate proportions of at least one reason given for not publishing studies. The proportion of non-submission among unpublished studies ranged from 55% to 100%, with a median of 85%. The reasons given by investigators for not publishing their studies included: lack of time or low priority (median 33%), studies being incomplete (median 15%), study not for publication (median 14%), manuscript in preparation or under review (median 12%), unimportant or negative result (median 12%), poor study quality or design (median 11%), fear of rejection (median 12%), rejection by journals (median 6%), author or co-author problems (median 10%), and sponsor or funder problems (median 9%). In general, the frequency of reasons given for non-publication was not associated with the source of unpublished studies, study design, or time when a survey was conducted. Conclusions Non-submission of studies for publication remains the main cause of non-publication of studies. Measures to reduce non-publication of studies and alternative models of research dissemination need to be developed to address the main reasons given by investigators for not publishing their studies, such as lack of time or low priority and fear of being rejected by journals. PMID:25335091

Motives for participating in a clinical research trial: a pilot study in Brazil.

PubMed

Nappo, Solange A; Iafrate, Giovanna B; Sanchez, Zila M

2013-01-10

In the past, clinical study participants have suffered from the experiments that they were subjected to. Study subjects may not understand the study process or may participate in clinical studies because they do not have access to medical care. The objectives of the present study were 1. to analyze the motives that might cause a volunteer to participate as a study subject; 2. to identify the social-demographic profile of this study subjects; and 3. to determine whether the motives to volunteer as a study subject are in accordance with the established legal and ethical principles for research in Brazil. Mixed-methods research was used (a qualitative-quantitative approach). A sample of 80 volunteers underwent a semi-structured interview, which was based on a survey script that was elaborated from discussions with key informants. The sample was randomly selected from a database of clinical study volunteers that was provided by Brazilian clinical study centers. The interviews were recorded and transcribed. Descriptive statistics were used for content analysis, including contingency tables with hypothesis testing. The motivations for clinical study participation were linked to types of benefit. The most frequently encountered motivations were financial gain and therapeutic alternative. Altruism was not a common motivator, and when altruism was present, it was observed as a secondary motivator. All participants reported that they understood the Informed Consent Statement (ICS). However, only two parts of the form were remembered by all of the volunteers: the section on being able to leave the study at any point and the section that stated that there would be some responsible professional at their disposal for the entirety of the study. The present study shows that study participants are primarily motivated by personal benefit when volunteering to participate in clinical studies. Whether these study participants had an integral understanding of the ICS is not clear.

Effects of case management in community aged care on client and carer outcomes: a systematic review of randomized trials and comparative observational studies

PubMed Central

2012-01-01

Background Case management has been applied in community aged care to meet frail older people’s holistic needs and promote cost-effectiveness. This systematic review aims to evaluate the effects of case management in community aged care on client and carer outcomes. Methods We searched Web of Science, Scopus, Medline, CINAHL (EBSCO) and PsycINFO (CSA) from inception to 2011 July. Inclusion criteria were: no restriction on date, English language, community-dwelling older people and/or carers, case management in community aged care, published in refereed journals, randomized control trials (RCTs) or comparative observational studies, examining client or carer outcomes. Quality of studies was assessed by using such indicators as quality control, randomization, comparability, follow-up rate, dropout, blinding assessors, and intention-to-treat analysis. Two reviewers independently screened potentially relevant studies, extracted information and assessed study quality. A narrative summary of findings were presented. Results Ten RCTs and five comparative observational studies were identified. One RCT was rated high quality. Client outcomes included mortality (7 studies), physical or cognitive functioning (6 studies), medical conditions (2 studies), behavioral problems (2 studies) , unmet service needs (3 studies), psychological health or well-being (7 studies) , and satisfaction with care (4 studies), while carer outcomes included stress or burden (6 studies), satisfaction with care (2 studies), psychological health or well-being (5 studies), and social consequences (such as social support and relationships with clients) (2 studies). Five of the seven studies reported that case management in community aged care interventions significantly improved psychological health or well-being in the intervention group, while all the three studies consistently reported fewer unmet service needs among the intervention participants. In contrast, available studies reported mixed results regarding client physical or cognitive functioning and carer stress or burden. There was also limited evidence indicating significant effects of the interventions on the other client and carer outcomes as described above. Conclusions Available evidence showed that case management in community aged care can improve client psychological health or well-being and unmet service needs. Future studies should investigate what specific components of case management are crucial in improving clients and their carers’ outcomes. PMID:23151143

Final report on low-dose estramustine phosphate (EMP) monotherapy and very low-dose EMP therapy combined with LH-RH agonist for previously untreated advanced prostate cancer.

PubMed

Kitamura, T; Suzuki, M; Nishimatsu, H; Kurosaki, T; Enomoto, Y; Fukuhara, H; Kume, H; Takeuchi, T; Miao, L; Jiangang, H; Xiaoqiang, L

2010-01-01

In order to assess the efficacy and toxicity of oral estramustine phosphate (EMP) administration, low-dose EMP monotherapy (study 1) and very low-dose EMP therapy with luteinizing hormone-releasing hormone (LH-RH) agonist (study 2) were conducted in previously untreated prostate cancer and long-term outcomes were compared between the 2 study groups. Studies 1 and 2 were independently performed beginning in June 1999 and November 2001, respectively. Study 1 was composed of 87 patients including 85 assessable patients. All 108 patients recruited for study 2 were assessable. Low-dose EMP monotherapy (2 capsules/day or 280 mg/day) was used in study 1 and very low-dose EMP (1 capsule/day or 140 mg/day) combined with LH-RH agonist was adopted in study 2. Overall prostate specific antigen (PSA) -response rates in studies 1 and 2 were 92.3% and 94.2%, respectively, and overall toxicity rates were 54.1% and 38.9%, respectively. EMP discontinuation due to side effects was encountered more often in study 1 (45.9%) than in study 2 (27.8%). Among the adverse side effects gastrointestinal toxicity was most prevalent in both studies. One patient died of acute pulmonary embolism in study 1, but no one died in study 2. There were 6 cancer deaths in the gastrointestinal tract in study 1 but only 2 cancer deaths in study 2. Our data indicate that the overall PSA response rate was comparable between both studies. However, rates in overall toxicity and drug discontinuation were higher in study 1 than in study 2. We consider that study 2 is more promising for the treatment of previously untreated advanced prostate cancer, although the rate of adverse side effects is still high as compared with other hormonal therapies. In order to overcome the high toxicity rate, especially the gastrointestinal toxicity, we recently elaborated a method employing tailor-made medicine using SNPs of 1A1 gene in cytochrome P-450 for decreasing the rate of gastrointestinal toxicity. Using this method of patient selection, study 3 has been successfully launched on September 2005 with high drug compliance. Better clinical results are being accumulated.

Mid-Pacific Marine Laboratory. Annual report for the period, 1 October 1977--30 September 1978

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reese, E.S.; Johnson, V.R. Jr.

1979-03-01

Studies on behavior included reproduction and sociobiology of reef fishes and aggression, hearing, and ultrasonic telemetry in sharks. Ecological studies included population, growth, and mortality studies on birds, corals, crustacea, echinoderms, fishes, molluscs, and rats. Geochemistry studies included biogeochemistry of reef organisms and hydrogeochemistry of groundwater. Geology studies included bioerosion of sea urchins, biology of endolithic processes, and survey of soils. Oceanography studies were conducted on lagoon circulation. Physiological studies were conducted on symbiosis in corals and utilization of organic material by Foraminifera. Studies on systematics of algae, echinoderms, and fishes were conducted. (HLW)

Pooling job physical exposure data from multiple independent studies in a consortium study of carpal tunnel syndrome

PubMed Central

Kapellusch, Jay M.; Garg, Arun; Bao, Stephen S.; Silverstein, Barbara A.; Burt, Susan E.; Dale, Ann Marie; Evanoff, Bradley A.; Gerr, Frederic E.; Harris-Adamson, Carisa; Hegmann, Kurt T.; Merlino, Linda A.; Rempel, David M.

2015-01-01

Pooling data from different epidemiological studies of musculoskeletal disorders (MSDs) is necessary to improve statistical power and to more precisely quantify exposure–response relationships for MSDs. The pooling process is difficult and time-consuming, and small methodological differences could lead to different exposure–response relationships. A subcommittee of a six-study research consortium studying carpal tunnel syndrome: (i) visited each study site, (ii) documented methods used to collect physical exposure data and (iii) determined compatibility of exposure variables across studies. Certain measures of force, frequency of exertion and duty cycle were collected by all studies and were largely compatible. A portion of studies had detailed data to investigate simultaneous combinations of force, frequency and duration of exertions. Limited compatibility was found for hand/wrist posture. Only two studies could calculate compatible Strain Index scores, but Threshold Limit Value for Hand Activity Level could be determined for all studies. Challenges of pooling data, resources required and recommendations for future researchers are discussed. PMID:23697792

The BioStudies database-one stop shop for all data supporting a life sciences study.

PubMed

Sarkans, Ugis; Gostev, Mikhail; Athar, Awais; Behrangi, Ehsan; Melnichuk, Olga; Ali, Ahmed; Minguet, Jasmine; Rada, Juan Camillo; Snow, Catherine; Tikhonov, Andrew; Brazma, Alvis; McEntyre, Johanna

2018-01-04

BioStudies (www.ebi.ac.uk/biostudies) is a new public database that organizes data from biological studies. Typically, but not exclusively, a study is associated with a publication. BioStudies offers a simple way to describe the study structure, and provides flexible data deposition tools and data access interfaces. The actual data can be stored either in BioStudies or remotely, or both. BioStudies imports supplementary data from Europe PMC, and is a resource for authors and publishers for packaging data during the manuscript preparation process. It also can support data management needs of collaborative projects. The growth in multiomics experiments and other multi-faceted approaches to life sciences research mean that studies result in a diversity of data outputs in multiple locations. BioStudies presents a solution to ensuring that all these data and the associated publication(s) can be found coherently in the longer term. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Methodology or method? A critical review of qualitative case study reports.

PubMed

Hyett, Nerida; Kenny, Amanda; Dickson-Swift, Virginia

2014-01-01

Despite on-going debate about credibility, and reported limitations in comparison to other approaches, case study is an increasingly popular approach among qualitative researchers. We critically analysed the methodological descriptions of published case studies. Three high-impact qualitative methods journals were searched to locate case studies published in the past 5 years; 34 were selected for analysis. Articles were categorized as health and health services (n=12), social sciences and anthropology (n=7), or methods (n=15) case studies. The articles were reviewed using an adapted version of established criteria to determine whether adequate methodological justification was present, and if study aims, methods, and reported findings were consistent with a qualitative case study approach. Findings were grouped into five themes outlining key methodological issues: case study methodology or method, case of something particular and case selection, contextually bound case study, researcher and case interactions and triangulation, and study design inconsistent with methodology reported. Improved reporting of case studies by qualitative researchers will advance the methodology for the benefit of researchers and practitioners.

Effective leadership in salient groups: revisiting leader-member exchange theory from the perspective of the social identity theory of leadership.

PubMed

Hogg, Michael A; Martin, Robin; Epitropaki, Olga; Mankad, Aditi; Svensson, Alicia; Weeden, Karen

2005-07-01

Two studies compared leader-member exchange (LMX) theory and the social identity theory of leadership. Study 1 surveyed 439 employees of organizations in Wales, measuring work group salience, leader-member relations, and perceived leadership effectiveness. Study 2 surveyed 128 members of organizations in India, measuring identification not salience and also individualism/collectivism. Both studies provided good support for social identity predictions. Depersonalized leader-member relations were associated with greater leadership effectiveness among high-than low-salient groups (Study 1) and among high than low identifiers (Study 2). Personalized leadership effectiveness was less affected by salience (Study 1) and unaffected by identification (Study 2). Low-salience groups preferred personalized leadership more than did high-salience groups (Study 1). Low identifiers showed no preference but high identifiers preferred depersonalized leadership (Study 2). In Study 2, collectivists did not prefer depersonalized as opposed to personalized leadership, whereas individualists did, probably because collectivists focus more on the relational self.

Optimal designs for prediction studies of whiplash.

PubMed

Kamper, Steven J; Hancock, Mark J; Maher, Christopher G

2011-12-01

Commentary. To provide guidance for the design and interpretation of predictive studies of whiplash associated disorders (WAD). Numerous studies have sought to define and explain the clinical course and response to treatment of people with WAD. Design of these studies is often suboptimal, which can lead to biased findings and issues with interpreting the results. Literature review and commentary. Predictive studies can be grouped into four broad categories; studies of symptomatic course, studies that aim to identify factors that predict outcome, studies that aim to isolate variables that are causally responsible for outcome, and studies that aim to identify patients who respond best to particular treatments. Although the specific research question will determine the optimal methods, there are a number of generic features that should be incorporated into design of such studies. The aim of these features is to minimize bias, generate adequately precise prognostic estimates, and ensure generalizability of the findings. This paper provides a summary of important considerations in the design, conduct, and reporting of prediction studies in the field of whiplash.

Developing the DESCARTE Model: The Design of Case Study Research in Health Care.

PubMed

Carolan, Clare M; Forbat, Liz; Smith, Annetta

2016-04-01

Case study is a long-established research tradition which predates the recent surge in mixed-methods research. Although a myriad of nuanced definitions of case study exist, seminal case study authors agree that the use of multiple data sources typify this research approach. The expansive case study literature demonstrates a lack of clarity and guidance in designing and reporting this approach to research. Informed by two reviews of the current health care literature, we posit that methodological description in case studies principally focuses on description of case study typology, which impedes the construction of methodologically clear and rigorous case studies. We draw from the case study and mixed-methods literature to develop the DESCARTE model as an innovative approach to the design, conduct, and reporting of case studies in health care. We examine how case study fits within the overall enterprise of qualitatively driven mixed-methods research, and the potential strengths of the model are considered. © The Author(s) 2015.

Lunar Science Conference, 8th, Houston, Tex., March 14-18, 1977, Proceedings. Volume 1 - The moon and the inner solar system. Volume 2 - Petrogenetic studies of mare and highland rocks. Volume 3 - Planetary and lunar surfaces

NASA Technical Reports Server (NTRS)

Merril, R. B.

1977-01-01

Solar system processes are considered along with the origin and evolution of the moon, planetary geophysics, lunar basins and crustal layering, lunar magnetism, the lunar surface as a planetary probe, remote observations of lunar and planetary surfaces, earth-based measurements, integrated studies, physical properties of lunar materials, and asteroids, meteorites, and the early solar system. Attention is also given to studies of mare basalts, the kinetics of basalt crystallization, topical studies of mare basalts, highland rocks, experimental studies of highland rocks, geochemical studies of highland rocks, studies of materials of KREEP composition, a consortium study of lunar breccia 73215, topical studies on highland rocks, Venus, and regional studies of the moon. Studies of surface processes, are reported, taking into account cratering mechanics and fresh crater morphology, crater statistics and surface dating, effects of exposure and gardening, and the chemistry of surfaces.

Manned Mars System Study (MMSS): Mars transportation and facility study. Volume 1: Executive Summary

NASA Technical Reports Server (NTRS)

1990-01-01

The purpose of the study was to design and analyze systems for conducting human missions to Mars and the moon, with special emphasis on the transportation and facility infrastructure. This study was conducted by Martin Marietta Astronautics Group, with an important teaming role by Science Applications International Corporation (SAIC). This work included the studies and separate reports of the FY-1988 and 1989 case studies as well as special analyses and parametric studies.

Multiple imputation for IPD meta-analysis: allowing for heterogeneity and studies with missing covariates.

PubMed

Quartagno, M; Carpenter, J R

2016-07-30

Recently, multiple imputation has been proposed as a tool for individual patient data meta-analysis with sporadically missing observations, and it has been suggested that within-study imputation is usually preferable. However, such within study imputation cannot handle variables that are completely missing within studies. Further, if some of the contributing studies are relatively small, it may be appropriate to share information across studies when imputing. In this paper, we develop and evaluate a joint modelling approach to multiple imputation of individual patient data in meta-analysis, with an across-study probability distribution for the study specific covariance matrices. This retains the flexibility to allow for between-study heterogeneity when imputing while allowing (i) sharing information on the covariance matrix across studies when this is appropriate, and (ii) imputing variables that are wholly missing from studies. Simulation results show both equivalent performance to the within-study imputation approach where this is valid, and good results in more general, practically relevant, scenarios with studies of very different sizes, non-negligible between-study heterogeneity and wholly missing variables. We illustrate our approach using data from an individual patient data meta-analysis of hypertension trials. © 2015 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd. © 2015 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

Limited responsiveness related to the minimal important difference of patient-reported outcomes in rare diseases.

PubMed

Johnston, Bradley C; Miller, Patricia A; Agarwal, Arnav; Mulla, Sohail; Khokhar, Rabia; De Oliveira, Kyle; Hitchcock, Christine L; Sadeghirad, Behnam; Mohiuddin, Mukarram; Sekercioglu, Nigar; Seweryn, Michal; Koperny, Magdalena; Bala, Malgorzata M; Adams-Webber, Thomasin; Granados, Alicia; Hamed, Alaa; Crawford, Mark W; van der Ploeg, Ans T; Guyatt, Gordon H

2016-11-01

To explore the responsiveness of patient-reported outcomes (PROs) in interventional studies involving patients with rare lysosomal storage diseases (LSDs). We searched eight databases for experimental and nonexperimental studies. Pairs of trained reviewers independently screened articles and subsequently extracted data from the eligible studies. Among studies with 10 or more patients using a valid PRO, we assessed the responsiveness of PROs based on a reanalysis of the data using minimal important difference estimates. Our analyses focused on statistically significant within-group differences in PROs for observational studies or the statistically significant between-group differences in PRO scores for controlled studies. Of 2,679 unique records, 62 interventional studies addressing patients with Fabry (55%), Gaucher (19%), Pompe (16%), and mucopolysaccharidoses (11%) proved eligible. The most frequently used PROs were the Short-Form-36 (25 studies), Brief Pain Inventory (20 studies), EuroQoL-5D (9 studies), and the Fatigue Severity Scale (6 studies). Observational studies suggest that PROs sometimes detect significant within-group changes when present. Randomized trials raise questions regarding the responsiveness of PROs to small differences between groups. Most studies have relied on generic PROs to evaluate quality of life and symptoms in patients with rare LSDs. PROs appear more responsive in observational studies than randomized trials. Copyright © 2016 Elsevier Inc. All rights reserved.

Assessing study skills among university students: an Iranian survey.

PubMed

Didarloo, Alireza; Khalkhali, Hamid Reza

2014-05-05

Numerous studies have revealed that study skills have a constructive role on the academic performance of students, in addition to educational quality, student' intelligence, and their affective characteristics. This study aims to examine study skills and the factors influencing them among the health sciences students of Urmia University of Medical Sciences in Iran. This was a cross-sectional study carried out from May to November 2013. A total of 340 Urmia health sciences students were selected using a simple sampling method. Data were collected using the Study Skills Assessment Questionnaire of Counseling Center of Houston University and analyzed with descriptive and analytical statistics. The mean and standard deviation of the students' study skills were 172.5±23.2, out of a total score of 240. Around 1.2% of the study skills were weak; 86.8%, moderate; and 12%, good. Among the study skills, the scores of time management, and memory and concentration were better than the others. Also, there was a significant positive correlation between study skills scores and the students' family housing status and academic level (P<0.05). Although the majority of the participants had moderate study skills, these were not sufficient and far from good. Improving and promoting the study skills of university students require the designing and implementing of education programs for study strategies. Therefore, decision makers and planners in the educational areas of universities should consider the topic described above.

Case Study: Testing with Case Studies

ERIC Educational Resources Information Center

Herreid, Clyde Freeman

2015-01-01

This column provides original articles on innovations in case study teaching, assessment of the method, as well as case studies with teaching notes. This month's issue discusses using case studies to test for knowledge or lessons learned.

40 CFR 716.21 - Chemical specific reporting requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... bioconcentration, environmental fate studies on biodegradation, and health effects studies on pharmacokinetics... fate studies on hydrolysis and biodegradation and health effects studies on pharmacokinetics... on biodegradation and health effects studies on pharmacokinetics, subchronic toxicity, neurotoxicity...

40 CFR 716.21 - Chemical specific reporting requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... bioconcentration, environmental fate studies on biodegradation, and health effects studies on pharmacokinetics... fate studies on hydrolysis and biodegradation and health effects studies on pharmacokinetics... on biodegradation and health effects studies on pharmacokinetics, subchronic toxicity, neurotoxicity...

40 CFR 716.21 - Chemical specific reporting requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... bioconcentration, environmental fate studies on biodegradation, and health effects studies on pharmacokinetics... fate studies on hydrolysis and biodegradation and health effects studies on pharmacokinetics... on biodegradation and health effects studies on pharmacokinetics, subchronic toxicity, neurotoxicity...

40 CFR 716.21 - Chemical specific reporting requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... bioconcentration, environmental fate studies on biodegradation, and health effects studies on pharmacokinetics... fate studies on hydrolysis and biodegradation and health effects studies on pharmacokinetics... on biodegradation and health effects studies on pharmacokinetics, subchronic toxicity, neurotoxicity...

40 CFR 716.21 - Chemical specific reporting requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... bioconcentration, environmental fate studies on biodegradation, and health effects studies on pharmacokinetics... fate studies on hydrolysis and biodegradation and health effects studies on pharmacokinetics... on biodegradation and health effects studies on pharmacokinetics, subchronic toxicity, neurotoxicity...

Research News

MedlinePlus

... in Research Studies Participate in a Clinical Trial Surveys and Other Research Studies Participate in Genetic Studies Donate to Tissue ... Learn More Participate in Genetic Studies Learn More Surveys and Other Research Studies Learn More Donate to Tissue Banks Learn ...

Are They "American" Enough to Teach Social Studies?: Korean American Teachers' Social Studies Teaching Experiences in American Public Schools

ERIC Educational Resources Information Center

Choi, Yoonjung

2012-01-01

This study explores three Korean American social studies teachers' experiences of teaching social studies, focusing on their curricular and pedagogical perceptions and practices. Framed by sociocultural theory, this study aims to shed light on the heterogeneous stories and socially and culturally contextualized teaching experiences of Korean…

Study Abroad for Global Engagement: The Long-Term Impact of Mobility Experiences

ERIC Educational Resources Information Center

Paige, R. Michael; Fry, Gerald W.; Stallman, Elizabeth M.; Josic, Jasmina; Jon, Jae-Eun

2009-01-01

This paper reports on the preliminary results of a research project "'Beyond immediate impact: Study abroad for global engagement' (SAGE)" which examines the long-term impact of study abroad on various forms of global engagement. The study employs a retrospective tracer study and mixed methods research design. Survey results from 6391 study-abroad…

Examining English Language Learning Motivation of Adult International Learners Studying Abroad in the US

ERIC Educational Resources Information Center

Weger, Heather D.

2013-01-01

The present study reports on the motivations of adult, international learners of English, studying English 20 hours a week in a US-based Intensive English Program (IEP). Though often used as participants in language acquisition studies, there are few studies of these learners' motivational profiles. In the current study, a questionnaire designed…

78 FR 52548 - The National Children's Study, Vanguard (Pilot) Study Proposed Collection; 60-day Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-23

... the initiation of methodological substudies. The NCS Vanguard Study is a prospective, longitudinal pilot study of child health and development that will inform the design of the Main Study of the... variables and designed to collect core data at every study visit contact from the time that the enrolled...

Faculty Self-Study in the Elementary School. Working Papers. Revised Edition 1973.

ERIC Educational Resources Information Center

Pennsylvania State Dept. of Education, Harrisburg. Bureau of Planning and Evaluation.

This guide for the study of a school district by its faculty members and administrators, along with parents, begins with suggested procedures for initiating and conducting a self-study. The guide itself contains two major sections: comprehensive study areas and content study areas. Included in the comprehensive areas for study are administration…

43 CFR 404.47 - How will a feasibility study be conducted under this program?

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false How will a feasibility study be conducted... Studies § 404.47 How will a feasibility study be conducted under this program? Feasibility studies will be... feasibility study, including the Principles and Guidelines (incorporated by reference at § 404.4). You can...

A Parent's Guide to the Social Studies. Revised.

ERIC Educational Resources Information Center

Roselle, Daniel; Singleton, Laurel R.

This guide for parents seeks to answer seven questions concerning the social studies: (1) What is social studies? (2) Why is social studies important at every grade level? (3) What kinds of materials are used to teach social studies? (4) What teaching strategies are used in social studies classes? (5) What have the national reports on education…

A Parent's Guide to the Social Studies.

ERIC Educational Resources Information Center

Roselle, Daniel

1974-01-01

This guide gives parents answers to seven questions: (1) What are the social studies? (2) How are the social studies taught? (3) Why do social studies educators say that knowing information is not enough? (4) Why are there so many social studies courses? (5) What is happening to the language of the social studies? (6) What issues are discussed in…

Balancing Act: A Phenomenological Study of Female Adult Learners Who Successfully Persisted in Graduate Studies

ERIC Educational Resources Information Center

Shepherd, Jeff; Nelson, Barbara Mullins

2012-01-01

A study was conducted utilizing Cross' (1981) barriers to adult learning as a framework to better understand how adults successfully complete their graduate studies. Participants in the study were solicited via Facebook and LinkedIn. Three female adult learners who persisted in their graduate studies while balancing demands outside academics…

Interpretation in Historical Writing: The Study of Development in Librarianship.

ERIC Educational Resources Information Center

Colson, John Calvin

Study of the development of libraries and librarianship may be done only historically, by analysis of the records of development. Such study necessarily is interpretive because historical study does not establish facts, but proceeds from them. In historical study an hypothesis may not be used as in scientific study, because the hypothesis is not…

Opinions of Teachers and Preservice Teachers of Social Studies on Geo-Literacy

ERIC Educational Resources Information Center

Memisoglu, Hatice

2017-01-01

The purpose of this study is to investigate the opinions of teachers and preservice teachers of social studies on geo-literacy. The study used the qualitative research design of phenomenology to collect data. The study consisted of 20 teachers and 30 prospective teachers of social studies. The purposive sampling method of criterion sampling was…

Social Problem Solving Levels of Pre-Service Social Studies Teachers

ERIC Educational Resources Information Center

Içen, Mustafa; Öztaskin, Özlem Bektas

2017-01-01

The purpose of this study is to examine pre-service Social Studies teachers' social problem solving levels based on different variables. A total of 247 preservice Social Studies teachers (103 females (41.7%) and 144 males (58.3%)) from Erzincan University, Faculty of Education, Department of Social Studies Teaching participated in the study. The…

Study on the University Students' Self-Expressive Tendency in Mongolia

ERIC Educational Resources Information Center

Jagdag, Davaa; Dembereldorj, Zoljargal

2017-01-01

The study aimed to explore Mongolian students' tendency of self-expression and a conduct of self-study at one university of Mongolia. It employed quantitative research method to explore the relationship between self-expression and self-study and examined them in terms of age, gender, years of study and field of study. The chi-squared test found…

18 CFR 5.13 - Revised study plan and study plan determination.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Revised study plan and study plan determination. 5.13 Section 5.13 Conservation of Power and Water Resources FEDERAL ENERGY... APPLICATION PROCESS § 5.13 Revised study plan and study plan determination. (a) Within 30 days following the...

Social Studies Skills or Something Else? An Analysis of How the "Essential Social Studies Skills and Strategies" Reflects Social Studies Instruction

ERIC Educational Resources Information Center

Brugar, Kristy A.; Whitlock, Annie McMahon

2018-01-01

This article describes the National Council for the Social Studies (NCSS) collection of "Essential Social Studies Skills and Strategies" in terms of common approaches to social studies teaching and learning (e.g., informed social criticism, reflective inquiry, transmission). We conducted descriptive and inferential analyses and found…

40 CFR 160.130 - Conduct of a study.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Conduct of a study. 160.130 Section... LABORATORY PRACTICE STANDARDS Protocol for and Conduct of a Study § 160.130 Conduct of a study. (a) The study... conformity with the protocol. (c) Specimens shall be identified by test system, study, nature, and date of...

18 CFR 5.13 - Revised study plan and study plan determination.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Revised study plan and study plan determination. 5.13 Section 5.13 Conservation of Power and Water Resources FEDERAL ENERGY... APPLICATION PROCESS § 5.13 Revised study plan and study plan determination. (a) Within 30 days following the...

Exploring Individual Factors Affecting Business Students' Willingness to Study Abroad: A Case Study from the Caribbean

ERIC Educational Resources Information Center

Hernández-Díaz, Arleen; Fernández-Morales, Leticia M.; Vega-Vilca, José C.; Córdova-Claudio, Mario

2016-01-01

Despite a low rate of student participation in study abroad programs in the Caribbean, there is insufficient research about the individual factors that help determine business students' willingness to study or to participate in internship programs abroad. This study aims to explore business students' attitudes toward study abroad. The positive…

40 CFR 160.130 - Conduct of a study.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Conduct of a study. 160.130 Section... LABORATORY PRACTICE STANDARDS Protocol for and Conduct of a Study § 160.130 Conduct of a study. (a) The study... conformity with the protocol. (c) Specimens shall be identified by test system, study, nature, and date of...

75 FR 29754 - Claims of Confidentiality of Certain Chemical Identities Contained in Health and Safety Studies...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-27

... Certain Chemical Identities Contained in Health and Safety Studies and Data from Health and Safety Studies... identities in health and safety studies, and in data from health and safety studies, submitted under the.... Section 14(b) of TSCA does not extend confidential treatment to health and safety studies, or data from...

An Investigation of the Raudenbush (1988) Test for Studying Variance Heterogeneity.

ERIC Educational Resources Information Center

Harwell, Michael

1997-01-01

The meta-analytic method proposed by S. W. Raudenbush (1988) for studying variance heterogeneity was studied. Results of a Monte Carlo study indicate that the Type I error rate of the test is sensitive to even modestly platykurtic score distributions and to the ratio of study sample size to the number of studies. (SLD)

Secondary Social Studies Teachers' Experiences Implementing Common Core State Literacy Standards: A Phenomenological Study

ERIC Educational Resources Information Center

Webb, Krista Faith Huskey

2014-01-01

The purpose of this phenomenological study was to examine the experiences of secondary social studies teachers who implemented Common Core State Standards for English Language Arts & Literacy in history/social studies, science and technical subjects in social studies courses requiring End of Course Tests at secondary schools in one suburban…

Programs of Study: A Cross-Study Examination of Programs in Three States

ERIC Educational Resources Information Center

Stringfield, Sam; Shumer, Robert; Stipanovic, Natalie; Murphy, Nora

2013-01-01

The National Research Center on Career and Technical Education has supported four studies on one of the major components of Perkins legislation: programs of study. In this article, we present qualitative data linking the research center's longitudinal projects based on programs of study, via a one-time cross-case study of sites deemed highly…

40 CFR 152.94 - Citation of a public literature study or study generated at government expense.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Citation of a public literature study... literature study or study generated at government expense. (a) An applicant may demonstrate compliance for a... the public literature. (2) A valid study generated by, or at the expense of, any government (Federal...

40 CFR 152.94 - Citation of a public literature study or study generated at government expense.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Citation of a public literature study... literature study or study generated at government expense. (a) An applicant may demonstrate compliance for a... the public literature. (2) A valid study generated by, or at the expense of, any government (Federal...

40 CFR 152.94 - Citation of a public literature study or study generated at government expense.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Citation of a public literature study... literature study or study generated at government expense. (a) An applicant may demonstrate compliance for a... the public literature. (2) A valid study generated by, or at the expense of, any government (Federal...

40 CFR 152.94 - Citation of a public literature study or study generated at government expense.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Citation of a public literature study... literature study or study generated at government expense. (a) An applicant may demonstrate compliance for a... the public literature. (2) A valid study generated by, or at the expense of, any government (Federal...

"Oh Events" for the Professor: Studies and Stories of Religious Studies Abroad

ERIC Educational Resources Information Center

Barbour, John D.

2015-01-01

This response explains three ways in which the preceding essays are a significant contribution to the study of study abroad, explores three additional issues, and makes three suggestions for future work on religious studies and study abroad. This response is published alongside of six other essays, comprising a special section of the journal (see…