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Sample records for cementitious waste option

  1. Cementitious waste option scoping study report

    SciTech Connect

    Lee, A.E.; Taylor, D.D.

    1998-02-01

    A Settlement Agreement between the Department of Energy (DOE) and the State of Idaho mandates that all high-level radioactive waste (HLW) now stored at the Idaho Chemical Processing Plant (ICPP) on the Idaho National Engineering and Environmental Laboratory (INEEL) will be treated so that it is ready to be moved out of Idaho for disposal by a target date of 2035. This study investigates the nonseparations Cementitious Waste Option (CWO) as a means to achieve this goal. Under this option all liquid sodium-bearing waste (SBW) and existing HLW calcine would be recalcined with sucrose, grouted, canisterized, and interim stored as a mixed-HLW for eventual preparation and shipment off-Site for disposal. The CWO waste would be transported to a Greater Confinement Disposal Facility (GCDF) located in the southwestern desert of the US on the Nevada Test Site (NTS). All transport preparation, shipment, and disposal facility activities are beyond the scope of this study. CWO waste processing, packaging, and interim storage would occur over a 5-year period between 2013 and 2017. Waste transport and disposal would occur during the same time period.

  2. Direct cementitious waste option study report

    SciTech Connect

    Dafoe, R.E.; Losinski, S.J.

    1998-02-01

    A settlement agreement between the Department of Energy (DOE) and the State of Idaho mandates that all high-level radioactive waste (HLW) now stored at the Idaho Chemical Processing Plant (ICPP) will be treated so that it is ready to be moved out of Idaho for disposal by a target data of 2035. This study investigates the direct grouting of all ICPP calcine (including the HLW dry calcine and those resulting from calcining sodium-bearing liquid waste currently residing in the ICPP storage tanks) as the treatment method to comply with the settlement agreement. This method involves grouting the calcined waste and casting the resulting hydroceramic grout into stainless steel canisters. These canisters will be stored at the Idaho National Engineering and Environmental Laboratory (INEEL) until they are sent to a national geologic repository. The operating period for grouting treatment will be from 2013 through 2032, and all the HLW will be treated and in interim storage by the end of 2032.

  3. Cementitious Stabilization of Mixed Wastes with High Salt Loadings

    SciTech Connect

    Spence, R.D.; Burgess, M.W.; Fedorov, V.V.; Downing, D.J.

    1999-04-01

    Salt loadings approaching 50 wt % were tolerated in cementitious waste forms that still met leach and strength criteria, addressing a Technology Deficiency of low salt loadings previously identified by the Mixed Waste Focus Area. A statistical design quantified the effect of different stabilizing ingredients and salt loading on performance at lower loadings, allowing selection of the more effective ingredients for studying the higher salt loadings. In general, the final waste form needed to consist of 25 wt % of the dry stabilizing ingredients to meet the criteria used and 25 wt % water to form a workable paste, leaving 50 wt % for waste solids. The salt loading depends on the salt content of the waste solids but could be as high as 50 wt % if all the waste solids are salt.

  4. Characteristics of Cast Stone cementitious waste form for immobilization of secondary wastes from vitrification process

    NASA Astrophysics Data System (ADS)

    Chung, Chul-Woo; Um, Wooyong; Valenta, Michelle M.; Sundaram, S. K.; Chun, Jaehun; Parker, Kent E.; Kimura, Marcia L.; Westsik, Joseph H.

    2012-01-01

    The high-temperature in vitrification process of radioactive wastes could cause radioactive technetium ( 99Tc) in secondary liquid wastes to become volatile. Solidified cementitious waste forms at low temperature were developed to immobilize radioactive secondary waste. This research focuses on the characterization of a cementitious waste form called Cast Stone. Properties including compressive strength, surface area, phase composition, and technetium leaching were measured. The results indicate that technetium diffusivity is affected by simulant type. Additionally, ettringite and AFm (Al 2O 3-Fe 2O 3-mono) main crystalline phases were formed during hydration. The Cast Stone waste form passed the qualification requirements for a secondary waste form, which are compressive strength of 3.45 MPa and technetium diffusivity of 10 -9 cm 2/s. Cast Stone was found to be a good candidate for immobilizing secondary waste streams.

  5. Mixed waste management options

    SciTech Connect

    Owens, C.B.; Kirner, N.P.

    1991-12-31

    Disposal fees for mixed waste at proposed commercial disposal sites have been estimated to be $15,000 to $40,000 per cubit foot. If such high disposal fees are imposed, generators may be willing to apply extraordinary treatment or regulatory approaches to properly dispose of their mixed waste. This paper explores the feasibility of several waste management scenarios and attempts to answer the question: Can mixed waste be managed out of existence? Existing data on commercially generated mixed waste streams are used to identify the realm of mixed waste known to be generated. Each waste stream is evaluated from both a regulatory and technical perspective in order to convert the waste into a strictly low-level radioactive or a hazardous waste. Alternative regulatory approaches evaluated in this paper include a delisting petition, no migration petition, and a treatability variance. For each waste stream, potentially available treatment options are identified that could lead to these variances. Waste minimization methodology and storage for decay are also considered. Economic feasibility of each option is discussed broadly.

  6. CEMENTITIOUS GROUT FOR CLOSING SRS HIGH LEVEL WASTE TANKS - #12315

    SciTech Connect

    Langton, C.; Burns, H.; Stefanko, D.

    2012-01-10

    In 1997, the first two United States Department of Energy (US DOE) high level waste tanks (Tanks 17-F and 20-F: Type IV, single shell tanks) were taken out of service (permanently closed) at the Savannah River Site (SRS). In 2012, the DOE plans to remove from service two additional Savannah River Site (SRS) Type IV high-level waste tanks, Tanks 18-F and 19-F. These tanks were constructed in the late 1950's and received low-heat waste and do not contain cooling coils. Operational closure of Tanks 18-F and 19-F is intended to be consistent with the applicable requirements of the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and will be performed in accordance with South Carolina Department of Health and Environmental Control (SCDHEC). The closure will physically stabilize two 4.92E+04 cubic meter (1.3 E+06 gallon) carbon steel tanks and isolate and stabilize any residual contaminants left in the tanks. The closure will also fill, physically stabilize and isolate ancillary equipment abandoned in the tanks. A Performance Assessment (PA) has been developed to assess the long-term fate and transport of residual contamination in the environment resulting from the operational closure of the F-Area Tank Farm (FTF) waste tanks. Next generation flowable, zero-bleed cementitious grouts were designed, tested, and specified for closing Tanks 18-F and 19-F and for filling the abandoned equipment. Fill requirements were developed for both the tank and equipment grouts. All grout formulations were required to be alkaline with a pH of 12.4 and chemically reduction potential (Eh) of -200 to -400 to stabilize selected potential contaminants of concern. This was achieved by including Portland cement and Grade 100 slag in the mixes, respectively. Ingredients and proportions of cementitious reagents were selected and adjusted, respectively, to support the mass placement strategy developed by closure

  7. Waste E-glass particles used in cementitious mixtures

    SciTech Connect

    Chen, C.H.; Huang, R. . E-mail: ranhuang@mail.ntou.edu.tw; Wu, J.K.; Yang, C.C.

    2006-03-15

    The properties of concretes containing various waste E-glass particle contents were investigated in this study. Waste E-glass particles were obtained from electronic grade glass yarn scrap by grinding to small particle size. The size distribution of cylindrical glass particle was from 38 to 300 {mu}m and about 40% of E-glass particle was less than 150 {mu}m. The E-glass mainly consists of SiO{sub 2}, Al{sub 2}O{sub 3}, Ca O and MgO, and is indicated as amorphous by X-ray diffraction (XRD) technique. Compressive strength and resistance of sulfate attack and chloride ion penetration were significantly improved by utilizing proper amount of waste E-glass in concrete. The compressive strength of specimen with 40 wt.% E-glass content was 17%, 27% and 43% higher than that of control specimen at age of 28, 91 and 365 days, respectively. E-glass can be used in concrete as cementitious material as well as inert filler, which depending upon the particle size, and the dividing size appears to be 75 {mu}m. The workability decreased as the glass content increased due to reduction of fineness modulus, and the addition of high-range water reducers was needed to obtain a uniform mix. Little difference was observed in ASR testing results between control and E-glass specimens. Based on the properties of hardened concrete, optimum E-glass content was found to be 40-50 wt.%.

  8. Cementitious Grout for Closing SRS High Level Waste Tanks - 12315

    SciTech Connect

    Langton, C.A.; Stefanko, D.B.; Burns, H.H.; Waymer, J.; Mhyre, W.B.; Herbert, J.E.; Jolly, J.C. Jr.

    2012-07-01

    In 1997, the first two United States Department of Energy (US DOE) high level waste tanks (Tanks 17-F and 20-F: Type IV, single shell tanks) were taken out of service (permanently closed) at the Savannah River Site (SRS). In 2012, the DOE plans to remove from service two additional Savannah River Site (SRS) Type IV high-level waste tanks, Tanks 18-F and 19-F. These tanks were constructed in the late 1950's and received low-heat waste and do not contain cooling coils. Operational closure of Tanks 18-F and 19-F is intended to be consistent with the applicable requirements of the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and will be performed in accordance with South Carolina Department of Health and Environmental Control (SCDHEC). The closure will physically stabilize two 4.92E+04 cubic meter (1.3 E+06 gallon) carbon steel tanks and isolate and stabilize any residual contaminants left in the tanks. Ancillary equipment abandoned in the tanks will also be filled to the extent practical. A Performance Assessment (PA) has been developed to assess the long-term fate and transport of residual contamination in the environment resulting from the operational closure of the F-Area Tank Farm (FTF) waste tanks. Next generation flowable, zero-bleed cementitious grouts were designed, tested, and specified for closing Tanks 18-F and 19-F and for filling the abandoned equipment. Fill requirements were developed for both the tank and equipment grouts. All grout formulations were required to be alkaline with a pH of 12.4 and to be chemically reducing with a reduction potential (Eh) of -200 to -400. Grouts with this chemistry stabilize potential contaminants of concern. This was achieved by including Portland cement and Grade 100 slag in the mixes, respectively. Ingredients and proportions of cementitious reagents were selected and adjusted to support the mass placement strategy developed by

  9. Glass science tutorial: Lecture No. 8, introduction cementitious systems for Low-Level Waste immobilization

    SciTech Connect

    Young, J.F.; Kirkpatrick, R.J.; Mason, T.O.; Brough, A.

    1995-07-01

    This report presents details about cementitious systems for low-level waste immobilization. Topics discussed include: composition and properties of portland cement; hydration properties; microstructure of concrete; pozzolans; slags; zeolites; transport properties; and geological aspects of long-term durability of concrete.

  10. Appraisal of a cementitious material for waste disposal: Neutron imaging studies of pore structure and sorptivity

    SciTech Connect

    McGlinn, Peter J.; Beer, Frikkie C. de; Aldridge, Laurence P.; Radebe, Mabuti J.; Nshimirimana, Robert; Brew, Daniel R.M.; Payne, Timothy E.; Olufson, Kylie P.

    2010-08-15

    Cementitious materials are conventionally used in conditioning intermediate and low level radioactive waste. In this study a candidate cement-based wasteform has been investigated using neutron imaging to characterise the wasteform for disposal in a repository for radioactive materials. Imaging showed both the pore size distribution and the extent of the cracking that had occurred in the samples. The rate of the water penetration measured both by conventional sorptivity measurements and neutron imaging was greater than in pastes made from Ordinary Portland Cement. The ability of the cracks to distribute the water through the sample in a very short time was also evident. The study highlights the significant potential of neutron imaging in the investigation of cementitious materials. The technique has the advantage of visualising and measuring, non-destructively, material distribution within macroscopic samples and is particularly useful in defining movement of water through the cementitious materials.

  11. CEMENTITIOUS BARRIERS MODELING FOR PERFORMANCE ASSESSMENTS OF SHALLOW LAND BURIAL OF LOW LEVEL RADIOACTIVE WASTE - 9243

    SciTech Connect

    Taylor, G

    2009-01-09

    The Cementitious Barriers Partnership (CBP) was created to develop predictive capabilities for the aging of cementitious barriers over long timeframes. The CBP is a multi-agency, multi-national consortium working under a U.S. Department of Energy (DOE) Environmental Management (EM-21) funded Cooperative Research and Development Agreement (CRADA) with the Savannah River National Laboratory (SRNL) as the lead laboratory. Members of the CBP are SRNL, Vanderbilt University, the U.S. Nuclear Regulatory Commission (USNRC), National Institute of Standards and Technology (NIST), SIMCO Technologies, Inc. (Canada), and the Energy Research Centre of the Netherlands (ECN). A first step in developing advanced tools is to determine the current state-of-the-art. A review has been undertaken to assess the treatment of cementitious barriers in Performance Assessments (PA). Representatives of US DOE sites which have PAs for their low level waste disposal facilities were contacted. These sites are the Idaho National Laboratory, Oak Ridge National Laboratory, Los Alamos National Laboratory, Nevada Test Site, and Hanford. Several of the more arid sites did not employ cementitious barriers. Of those sites which do employ cementitious barriers, a wide range of treatment of the barriers in a PA was present. Some sites used conservative, simplistic models that even though conservative still showed compliance with disposal limits. Other sites used much more detailed models to demonstrate compliance. These more detailed models tend to be correlation-based rather than mechanistically-based. With the US DOE's Low Level Waste Disposal Federal Review Group (LFRG) moving towards embracing a risk-based, best estimate with an uncertainties type of analysis, the conservative treatment of the cementitious barriers seems to be obviated. The CBP is creating a tool that adheres to the LFRG chairman's paradigm of continuous improvement.

  12. The effect of concentration on the structure and crystallinity of a cementitious waste form for caustic wastes

    SciTech Connect

    Chung, Chul-Woo; Turo, Laura A.; Ryan, Joseph V.; Johnson, Bradley R.; McCloy, John S.

    2013-06-01

    Cement-based waste forms have long been considered economical technologies for disposal of various types of waste. A solidified cementitious waste form, Cast Stone, was developed to immobilize the radioactive secondary waste from vitrification processes. In this work, Cast Stone was considered for a Na-based caustic liquid waste, and its physical properties were analyzed as a function of liquid waste loading up to 2 M Na. Differences in crystallinity (phase composition), microstructure, mesostructure (pore size distribution, surface area), and macrostructure (density, compressive strength) were investigated using various analytical techniques, in order to assess the suitability of Cast Stone as a chemically durable waste. It was found that the concentration of secondary waste simulant (caustic waste) had little effect on the relevant engineering properties of Cast Stone, showing that Cast Stone could be an effective and tolerant waste form for a wide range of concentrations of high sodium waste.

  13. The effect of concentration on the structure and crystallinity of a cementitious waste form for caustic wastes

    NASA Astrophysics Data System (ADS)

    Chung, Chul-Woo; Turo, Laura A.; Ryan, Joseph V.; Johnson, Bradley R.; McCloy, John S.

    2013-06-01

    Cement-based waste forms have long been considered economical technologies for disposal of various types of waste. A solidified cementitious waste form, Cast Stone, has been identified to immobilize the radioactive secondary waste from vitrification processes. In this work, Cast Stone was considered for a Na-based caustic liquid waste, and its physical properties were analyzed as a function of liquid waste loading up to 2 M Na. Differences in crystallinity (phase composition), microstructure, mesostructure (pore size distribution and surface area), and macrostructure (density and compressive strength) were investigated using various analytical techniques, in order to assess the suitability of Cast Stone as a chemically durable waste. It was found that the concentration of secondary waste simulant (caustic waste) had little effect on the relevant engineering properties of Cast Stone, showing that Cast Stone could be an effective and tolerant waste form for a wide range of concentrations of high sodium waste.

  14. The evolution of clay rock/cement interfaces in a cementitious repository for low- and intermediate level radioactive waste

    NASA Astrophysics Data System (ADS)

    Kosakowski, Georg; Berner, Urs

    In Switzerland, deep geological storage in clay rich host rocks is the preferred option for low- and intermediate-level radioactive waste. For these waste types cementitious materials are used for tunnel support and backfill, waste containers and waste matrixes. The different geochemical characteristics of clay and cementitious materials may induce mineralogical and pore water changes which might affect the barrier functionality of host rocks and concretes. We present numerical reactive transport calculations that systematically compare the geochemical evolution at cement/clay interfaces for the proposed host rocks in Switzerland for different transport scenarios. We developed a consistent set of thermodynamic data, simultaneously valid for cementitious (concrete) and clay materials. With our setup we successfully reproduced mineralogies, water contents and pore water compositions of the proposed host rocks and of a reference concrete. Our calculations show that the effects of geochemical gradients between concrete and clay materials are very similar for all investigated host rocks. The mineralogical changes at material interfaces are restricted to narrow zones for all host rocks. The extent of strong pH increase in the host rocks is limited, although a slight increase of pH over greater distances seems possible in advective transport scenarios. Our diffusive and partially also the advective calculations show massive porosity changes due to precipitation/dissolution of mineral phases near the interface, in line with many other reported transport calculations on cement/clay interactions. For all investigated transport scenarios the degradation of concrete materials in emplacement caverns due to diffusive and advective transport of clay pore water into the caverns is limited to narrow zones. A specific effort has been made to improve the geochemical setup and the extensive use of solid solution phases demonstrated the successful application of a thermodynamically

  15. Setting and Stiffening of Cementitious Components in Cast Stone Waste Form for Disposal of Secondary Wastes from the Hanford waste treatment and immobilization plant

    SciTech Connect

    Chung, Chul-Woo; Chun, Jaehun; Um, Wooyong; Sundaram, S. K.; Westsik, Joseph H.

    2013-04-01

    Cast stone is a cementitious waste form, a viable option to immobilize secondary nuclear liquid wastes generated from Hanford vitrification plant. While the strength and radioactive technetium leaching of different waste form candidates have been reported, no study has been performed to understand the flow and stiffening behavior of Cast Stone, which is essential to ensure the proper workability, especially considering necessary safety as a nuclear waste form in a field scale application. The rheological and ultrasonic wave reflection (UWR) measurements were used to understand the setting and stiffening Cast Stone batches. X-ray diffraction (XRD) was used to find the correlation between specific phase formation and the stiffening of the paste. Our results showed good correlation between rheological properties of the fresh Cast Stone mixture and phase formation during hydration of Cast Stone. Secondary gypsum formation originating from blast furnace slag was observed in Cast Stone made with low concentration simulants. The formation of gypsum was suppressed in high concentration simulants. It was found that the stiffening of Cast Stone was strongly dependent on the concentration of simulant. A threshold concentration for the drastic change in stiffening was found at 1.56 M Na concentration.

  16. Setting and stiffening of cementitious components in Cast Stone waste form for disposal of secondary wastes from the Hanford waste treatment and immobilization plant

    SciTech Connect

    Chung, Chul-Woo; Chun, Jaehun Um, Wooyong; Sundaram, S.K.; Westsik, Joseph H.

    2013-04-01

    Cast Stone is a cementitious waste form, a viable option to immobilize secondary nuclear liquid wastes generated from the Hanford Waste Treatment and Immobilization Plant. However, no study has been performed to understand the flow and stiffening behavior, which is essential to ensure proper workability and is important to safety in a nuclear waste field-scale application. X-ray diffraction, rheology, and ultrasonic wave reflection methods were used to understand the specific phase formation and stiffening of Cast Stone. Our results showed a good correlation between rheological properties of the fresh mixture and phase formation in Cast Stone. Secondary gypsum formation was observed with low concentration simulants, and the formation of gypsum was suppressed in high concentration simulants. A threshold concentration for the drastic change in stiffening was found at 1.56 M Na concentration. It was found that the stiffening of Cast Stone was strongly dependent on the concentration of simulant. Highlights: • A combination of XRD, UWR, and rheology gives a better understanding of Cast Stone. • Stiffening of Cast Stone was strongly dependent on the concentration of simulant. • A drastic change in stiffening of Cast Stone was found at 1.56 M Na concentration.

  17. Heat of Hydration of Low Activity Cementitious Waste Forms

    SciTech Connect

    Nasol, D.

    2015-07-23

    During the curing of secondary waste grout, the hydraulic materials in the dry mix react exothermally with the water in the secondary low-activity waste (LAW). The heat released, called the heat of hydration, can be measured using a TAM Air Isothermal Calorimeter. By holding temperature constant in the instrument, the heat of hydration during the curing process can be determined. This will provide information that can be used in the design of a waste solidification facility. At the Savannah River National Laboratory (SRNL), the heat of hydration and other physical properties are being collected on grout prepared using three simulants of liquid secondary waste generated at the Hanford Site. From this study it was found that both the simulant and dry mix each had an effect on the heat of hydration. It was also concluded that the higher the cement content in the dry materials mix, the greater the heat of hydration during the curing of grout.

  18. Frequency Characteristics of Acoustic Emission Signals from Cementitious Waste-forms with Encapsulated Al

    SciTech Connect

    Spasova, Lyubka M.; Ojovan, Michael I.

    2007-07-01

    Acoustic emission (AE) signals were continuously recorded and their intrinsic frequency characteristics examined in order to evaluate the mechanical performance of cementitious wasteform samples with encapsulated Al waste. The primary frequency in the power spectrum and its range of intensity for the detected acoustic waves were potentially related with appearance of different micro-mechanical events caused by Al corrosion within the encapsulating cement system. In addition the process of cement matrix hardening has been shown as a source of AE signals characterized with essentially higher primary frequency (above 2 MHz) compared with those due to Al corrosion development (below 40 kHz) and cement cracking (above 100 kHz). (authors)

  19. Managing Nuclear Waste: Options Considered

    SciTech Connect

    DOE

    2002-05-02

    Starting in the 1950s, U.S. scientists began to research ways to manage highly radioactive materials accumulating at power plants and other sites nationwide. Long-term surface storage of these materials poses significant potential health, safety, and environmental risks. Scientists studied a broad range of options for managing spent nuclear fuel and high-level radioactive waste. The options included leaving it where it is, disposing of it in various ways, and making it safer through advanced technologies. International scientific consensus holds that these materials should eventually be disposed of deep underground in what is called a geologic repository. In a recent special report, the National Academy of Sciences summarized the various studies and emphasized that geologic disposal is ultimately necessary.

  20. Interpretation of leaching data for cementitious waste forms using analytical solutions based on mass transport theory and empiricism

    SciTech Connect

    Spence, R.D.; Godbee, H.W.; Tallent, O.K.; Nestor, C.W. Jr. )

    1989-01-01

    The analysis of leaching data using analytical solutions based on mass transport theory and empiricism is presented. The waste forms leached to generate the data used in this analysis were prepared with a simulated radioactive waste slurry with traces of potassium ion, manganese ions, carbonate ions, phosphate ions, and sulfate ions solidified with several blends of cementitious materials. Diffusion coefficients were estimated from the results of ANS - 16.1 tests. Data of fraction leached versus time is presented and discussed.

  1. Transient Thermal Response of Lightweight Cementitious Composites Made with Polyurethane Foam Waste

    NASA Astrophysics Data System (ADS)

    Kismi, M.; Poullain, P.; Mounanga, P.

    2012-07-01

    The development of low-cost lightweight aggregate (LWA) mortars and concretes presents many advantages, especially in terms of lightness and thermal insulation performances of structures. Low-cost LWA mainly comes from the recovery of vegetal or plastic wastes. This article focuses on the characterization of the thermal conductivity of innovative lightweight cementitious composites made with fine particles of rigid polyurethane (PU) foam waste. Five mortars were prepared with various mass substitution rates of cement with PU-foam particles. Their thermal conductivity was measured with two transient methods: the heating-film method and the hot-disk method. The incorporation of PU-foam particles causes a reduction of up to 18 % of the mortar density, accompanied by a significant improvement of the thermal insulating performance. The effect of segregation on the thermal properties of LWA mortars due to the differences of density among the cementitious matrix, sand, and LWA has also been quantified. The application of the hot-disk method reveals a gradient of thermal conductivity along the thickness of the specimens, which could be explained by a non-uniform repartition of fine PU-foam particles and mineral aggregates within the mortars. The results show a spatial variation of the thermal conductivity of the LWA mortars, ranging from 9 % to 19 %. However, this variation remains close to or even lower than that observed on a normal weight aggregate mortar. Finally, a self-consistent approach is proposed to estimate the thermal conductivity of PU-foam cement-based composites.

  2. Waste disposal options report. Volume 1

    SciTech Connect

    Russell, N.E.; McDonald, T.G.; Banaee, J.; Barnes, C.M.; Fish, L.W.; Losinski, S.J.; Peterson, H.K.; Sterbentz, J.W.; Wenzel, D.R.

    1998-02-01

    This report summarizes the potential options for the processing and disposal of mixed waste generated by reprocessing spent nuclear fuel at the Idaho Chemical Processing Plant. It compares the proposed waste-immobilization processes, quantifies and characterizes the resulting waste forms, identifies potential disposal sites and their primary acceptance criteria, and addresses disposal issues for hazardous waste.

  3. Effect of calcite on lead-rich cementitious solid waste forms

    SciTech Connect

    Lee, Dongjin; Swarbrick, Gareth; Waite, T. David . E-mail: D.waite@unsw.edu.au

    2005-06-01

    The effect of calcite on lead-rich solidified waste forms generated using Portland cement has been investigated. Samples of cementitious wastes in the absence and presence of Pb and in the absence and presence of calcite were examined separately at 2, 7, 14 and 28 days of hydration by X-ray diffraction and SEM/EDS and for compressive strength. The presence of lead was observed to produce lead carbonate sulfate hydroxide (Pb{sub 4}SO{sub 4}(CO{sub 3}){sub 2}(OH){sub 2}), lead carbonate hydroxide hydrate (3PbCO{sub 3}.2Pb(OH){sub 2}.H{sub 2}O) and two other unidentified lead salts in cavity areas, and was observed to significantly retard the hydration of cement. Calcite addition to the Pb wastes was found to induce the rapid crystallization of calcium hydroxide coincident with the onset of C-S-H gel germination. The rapid dissolution of lead precipitates was observed with the subsequent development of very insoluble gel products of the form C-Pb-S-H. These products are formed by chemical incorporation of re-dissolved Pb species into silicate structures.

  4. Valorization of post-consumer waste plastic in cementitious concrete composites.

    PubMed

    Marzouk, O Yazoghli; Dheilly, R M; Queneudec, M

    2007-01-01

    The sheer amount of disposable bottles being produced nowadays makes it imperative to identify alternative procedures for recycling them since they are non-biodegradable. This paper describes an innovative use of consumed plastic bottle waste as sand-substitution aggregate within composite materials for building application. Particularly, bottles made of polyethylene terephthalate (PET) have been used as partial and complete substitutes for sand in concrete composites. Various volume fractions of sand varying from 2% to 100% were substituted by the same volume of granulated plastic, and various sizes of PET aggregates were used. The bulk density and mechanical characteristics of the composites produced were evaluated. To study the relationship between mechanical properties and composite microstructure, scanning electron microscopy technique was employed. The results presented show that substituting sand at a level below 50% by volume with granulated PET, whose upper granular limit equals 5mm, affects neither the compressive strength nor the flexural strength of composites. This study demonstrates that plastic bottles shredded into small PET particles may be used successfully as sand-substitution aggregates in cementitious concrete composites. These new composites would appear to offer an attractive low-cost material with consistent properties; moreover, they would help in resolving some of the solid waste problems created by plastics production and in saving energy. PMID:16730969

  5. The role of oxygen diffusion in the release of technetium from reducing cementitious waste forms

    SciTech Connect

    Smith, R.W.; Walton, J.C.

    1993-12-31

    Cementitious materials provide an ideal geochemical environment (e.g., high pH pore fluids and large surface areas for sorption) for immobilizing nuclear waste. The inclusion of reducing agents, such as blast furnace slag (BFS) can immobilize radionuclides by forming of solid sulfide phases. Thermodynamic calculations using the MINTEQ geochemical computer code indicate the elemental sulfur present in BPS reacts with the highly mobile pertechnetate anion (TcO{sub 4}{sup -}) anion to form an insoluble technetium sulfide phase (Tc{sub 2}S{sub 7(s)}). Initially, the waste form very effectively immobilizes technetium. However, as oxygen diffuses into the waste form, an outer zone of oxidized concrete and a shrinking core of reduced intact concrete develops. Oxidation of sulfur in the outer zone results in increased technetium concentrations in the pore fluid because Tc{sub 2}S{sub 7(a)} oxidizes to the mobile TcO{sub 4}{sup -} anion. The TcO{sub 4}{sup -} anion can then diffuse from the waste form into the environment. A mathematical model that accounts for diffusion of oxygen into concrete coupled with oxidation of sulfur and sulfide to sulfate has been developed. This model assumes the existence of an oxidized outer layer of concrete surrounding a shrinking core of reducing intact concrete. A sharp boundary between the two zones moves slowly inward resulting in oxidation of Tc{sub 2}S{sub 7(s)} and subsequent release of TcO{sub 4}{sup -} via aqueous diffusion in the concrete pore fluids. The model indicates that this mechanism results in a linear dependance of release with the square root of time similar to pure diffusion. In addition, the release of technetium is related to the inverse of the square root of the concentration of BFS, indicating that performance will significantly increases with the addition of approximately 20 percent BFS to the cement mix.

  6. Long-term degradation (or improvement?) of cementitious grout/concrete for waste disposal at Hanford

    SciTech Connect

    Piepho, M.G.

    1997-12-31

    If grout and/or concrete barriers and containments are considered for long-term (500 yrs to 100,000 ) waste disposal, then long-term degradation of grout/cement materials (and others) need to be studied. Long-term degradations of a cementitious grout monolith (15.4mW x 10.4mH x 37.6mL) and its containment concrete shell and asphalt shell (each 1-m thick) were analyzed. The main degradation process of the concrete shell was believed to be fractures due to construction joints, shrinkage, thermal stress, settlement, and seismic events. A scenario with fractures was modeled (flow and transport model) for long-term risk performance (out to a million yrs). Even though the concrete/grout is expected to fracture, the concrete/grout chemistry, which has high Ph value, is very beneficial in causing calcite deposits from calcium in the water precipitating in the fractures. These calcite deposits will tend to plug the fracture and keep water from entering. The effectiveness of such plugging needs to be studied more. It`s possible that the plugged fractures are more impermeable than the original concrete/grout. The long-term performance of concrete/grout barriers will be determined by its chemistry, not its mechanical properties.

  7. Zinc Bromide Waste Solution Treatment Options

    SciTech Connect

    Langston, C.A.

    2001-01-16

    The objective of this effort was to identify treatment options for 20,000 gallons of low-level radioactively contaminated zinc bromide solution currently stored in C-Area. These options will be relevant when the solutions are declared waste.

  8. INTERNATIONAL PROGRAM: SUMMARY REPORT ON THE PROPERTIES OF CEMENTITIOUS WASTE FORMS

    SciTech Connect

    Harbour, J

    2007-03-02

    This report provides a summary of the results on the properties of cementitious waste forms obtained as part of the International Program. In particular, this report focuses on the results of Task 4 of the Program that was initially entitled ''Improved Retention of Key Contaminants of Concern in Low Temperature Immobilized Waste Forms''. Task 4 was a joint program between Khlopin Radium Institute and the Savannah River National Laboratory. The task evolved during this period into a study of cementitious waste forms with an expanded scope that included heat of hydration and fate and transport modeling. This report provides the results for Task 4 of the International Program as of the end of FY06 at which time funding for Task 4 was discontinued due to the needs of higher priority tasks within the International Program. Consequently, some of the subtasks were only partially completed, but it was considered important to capture the results up to this point in time. Therefore, this report serves as the closeout report for Task 4. The degree of immobilization of Tc-99 within the Saltstone waste form was measured through monolithic and crushed grout leaching tests. An effective diffusion coefficient of 4.8 x 10{sup -12} (Leach Index of 11.4) was measured using the ANSI/ANS-16.1 protocol which is comparable with values obtained for tank closure grouts using a dilute salt solution. The leaching results show that, in the presence of concentrated salt solutions such as those that will be processed at the Saltstone Production Facility, blast furnace slag can effectively reduce pertechnetate to the immobile +4 oxidation state. Leaching tests were also initiated to determine the degree of immobilization of selenium in the Saltstone waste form. Results were obtained for the upper bound of projected selenium concentration ({approx}5 x 10{sup -3} M) in the salt solution that will be treated at Saltstone. The ANSI/ANS 16.1 leaching tests provided a value for the effective

  9. The solubility of nickel and its migration through the cementitious backfill of a geological disposal facility for nuclear waste.

    PubMed

    Felipe-Sotelo, M; Hinchliff, J; Field, L P; Milodowski, A E; Holt, J D; Taylor, S E; Read, D

    2016-08-15

    This work describes the solubility of nickel under the alkaline conditions anticipated in the near field of a cementitious repository for intermediate level nuclear waste. The measured solubility of Ni in 95%-saturated Ca(OH)2 solution is similar to values obtained in water equilibrated with a bespoke cementitious backfill material, on the order of 5×10(-7)M. Solubility in 0.02M NaOH is one order of magnitude lower. For all solutions, the solubility limiting phase is Ni(OH)2; powder X-ray diffraction and scanning transmission electron microscopy indicate that differences in crystallinity are the likely cause of the lower solubility observed in NaOH. The presence of cellulose degradation products causes an increase in the solubility of Ni by approximately one order of magnitude. The organic compounds significantly increase the rate of Ni transport under advective conditions and show measurable diffusive transport through intact monoliths of the cementitious backfill material. PMID:27198634

  10. Photovoltaic's silica-rich waste sludge as supplementary cementitious material (SCM)

    SciTech Connect

    Quercia, G.; Putten, J.J.G. van der; Hüsken, G.; Brouwers, H.J.H.

    2013-12-15

    Waste sludge, a solid recovered from wastewater of photovoltaic-industries, composes of agglomerates of nano-particles like SiO{sub 2} and CaCO{sub 3}. This sludge deflocculates in aqueous solutions into nano-particles smaller than 1 μm. Thus, this sludge constitutes a potentially hazardous waste when it is improperly disposed. Due to its high content of amorphous SiO{sub 2}, this sludge has a potential use as supplementary cementitious material (SCM) in concrete. In this study the main properties of three different samples of photovoltaic's silica-rich waste sludge (nSS) were physically and chemically characterized. The characterization techniques included: scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), nitrogen physical adsorption isotherm (BET method), density by Helium pycnometry, particle size distribution determined by laser light scattering (LLS) and zeta-potential measurements by dynamic light scattering (DLS). In addition, a dispersability study was performed to design stable slurries to be used as liquid additives for the concrete production on site. The effects on the hydration kinetics of cement pastes by the incorporation of nSS in the designed slurries were determined using an isothermal calorimeter. A compressive strength test of standard mortars with 7% of cement replacement was performed to determine the pozzolanic activity of the waste nano-silica sludge. Finally, the hardened system was fully characterized to determine the phase composition. The results demonstrate that the nSS can be utilized as SCM to replace portion of cement in mortars, thereby decreasing the CO{sub 2} footprint and the environmental impact of concrete. -- Highlights: •Three different samples of PV nano-silica sludge (nSS) were fully characterized. •nSS is composed of agglomerates of nano-particles like SiO{sub 2} and CaCO{sub 3}. •Dispersability studies demonstrated that nSS agglomerates are broken to nano

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

    SciTech Connect

    Burns, Heather; Flach, Greg; Smith, Frank; Langton, Christine; Brown, Kevin; Mallick, Pramod

    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 and 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

  12. Modelling the leaching of Pb, Cd, As, and Cr from cementitious waste using PHREEQC.

    PubMed

    Halim, Cheryl E; Short, Stephen A; Scott, Jason A; Amal, Rose; Low, Gary

    2005-10-17

    A leaching model was developed using the United States Geological Survey public domain PHREEQC geochemical package to simulate the leaching of Pb, Cd, As, and Cr from cementitious wastes. The model utilises both kinetic terms and equilibrium thermodynamics of key compounds and provides information on leachate and precipitate speciation. The model was able to predict the leaching of Pb, Cd, As, and Cr from cement in the presence of both simple (0.1 and 0.6M acetic acid) and complex municipal landfill leachates. Heavy metal complexation by the municipal landfill leachate was accounted for by the introduction of a monoprotic organic species into the model. The model indicated Pb and As were predominantly incorporated within the calcium silicate hydrate matrix while a greater portion of Cd was seen to exist as discrete particles in the cement pores and Cr (VI) existed mostly as free CrO4(2-) ions. Precipitation was found to be the dominant mechanism controlling heavy metal solubility with carbonate and silicate species governing the solubility of Pb and carbonate, silicate and hydroxide species governing the solubility of Cd. In the presence of acetic acid, at low pH values Pb and Cd acetate complexes were predominant whereas, at high pH values, hydroxide species dominated. At high pH values, the concentration of As in the leachate was governed by the solubility of Ca3(AsO4)2 with the presence of carbonate alkalinity competing with arsenate for Ca ions. In the presence of municipal landfill leachate, Pb and Cd organic complexes dominated the heavy metal species in solution. The reduction of As and Cr in municipal landfill leachate was crucial for determining aqueous speciation, with typical municipal landfill conditions providing the reduced forms of As and Cr. PMID:16043281

  13. Waste disposal options report. Volume 2

    SciTech Connect

    Russell, N.E.; McDonald, T.G.; Banaee, J.; Barnes, C.M.; Fish, L.W.; Losinski, S.J.; Peterson, H.K.; Sterbentz, J.W.; Wenzel, D.R.

    1998-02-01

    Volume 2 contains the following topical sections: estimates of feed and waste volumes, compositions, and properties; evaluation of radionuclide inventory for Zr calcine; evaluation of radionuclide inventory for Al calcine; determination of k{sub eff} for high level waste canisters in various configurations; review of ceramic silicone foam for radioactive waste disposal; epoxides for low-level radioactive waste disposal; evaluation of several neutralization cases in processing calcine and sodium-bearing waste; background information for EFEs, dose rates, watts/canister, and PE-curies; waste disposal options assumptions; update of radiation field definition and thermal generation rates for calcine process packages of various geometries-HKP-26-97; and standard criteria of candidate repositories and environmental regulations for the treatment and disposal of ICPP radioactive mixed wastes.

  14. Vitrified waste option study report

    SciTech Connect

    Lopez, D.A.; Kimmitt, R.R.

    1998-02-01

    A {open_quotes}Settlement Agreement{close_quotes} between the Department of Energy and the State of Idaho mandates that all radioactive high-level waste (HLW) now stored at the Idaho Chemical Processing Plant (ICPP) will be treated so that it is ready to be moved out of Idaho for disposal by a target date of 2035. This report investigates vitrification treatment of all ICPP calcine, including the existing and future HLW calcine resulting from calcining liquid Sodium-Bearing Waste (SBW). Currently, the SBW is stored in the tank farm at the ICPP. Vitrification of these wastes is an acceptable treatment method for complying with the Settlement Agreement. This method involves vitrifying the calcined waste and casting the vitrified mass into stainless steel canisters that will be ready to be moved out of the Idaho for disposal by 2035. These canisters will be stored at the Idaho National Engineering and Environmental Laboratory (INEEL) until they are sent to a HLW national repository. The operating period for vitrification treatment will be from 2013 through 2032; all HLW will be treated and in storage by the end of 2032.

  15. Intended long term performances of cementitious engineered barriers for future storage and disposal facilities for radioactive wastes in Romania

    NASA Astrophysics Data System (ADS)

    Fako, R.; Barariu, Gh.; Toma, R.; Georgescu, R.; Sociu, F.

    2013-07-01

    Considering the EU statements, Romania is engaged to endorse in the near future the IAEA relevant publications on geological repository (CNCANa), to update the Medium and Long Term National Strategy for Safe Management of Radioactive Waste and to approve the Road Map for Geological Repository Development. Currently, for example, spent fuel is wet stored for 6 years and after this period it is transported to dry storage in MACSTOR-200 (a concrete monolithic module) where it is intended to remain at least 50 years. The present situation for radioactive waste management in Romania is reviewed in the present paper. Focus will be done on existent disposal facilities but, also, on future facilities planned for storage / disposal of radioactive wastes. Considering specific data for Romanian radioactive waste inventory, authors are reviewing the advance in the radioactive waste management in Romania considering its particularities. The team tries to highlight the expected limitations and unknown data related with cementitious engineered barriers that has to be faced in the near future incase of interim storage or for the upcoming long periods of disposal.

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

    SciTech Connect

    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 speciation 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

  17. Experimental and Modeling Indications for Self-Sealing of a Cementitious Low- and Intermediate-Level Waste Repository by Calcite Precipitation

    SciTech Connect

    Pfingsten, Wilfried

    2002-10-15

    In the vicinity of a cementitious nuclear waste repository, mineral reactions will change the hydraulic conditions and the parameters describing radionuclide transport with time during the cement degradation phase. Porosity changes due to mineral and cement reactions will influence permeability and diffusivity. Formation water rich in CO{sub 2} will lead to calcite precipitation in the water-conducting zones surrounding the cementitious waste repository. This will have an impact on the radionuclide release from the cementitious repository into the host rock environment. The sequentially coupled flow, transport, and chemical reaction code MCOTAC is used to include such processes in the modeling. A porosity-permeability relation and a porosity-diffusivity relation are used for describing cement degradation and related secondary mineral precipitation and their coupling to reactive transport modeling. Two-dimensional model calculations are used to predict the temporal evolution of transport parameters for radionuclides within a 'small-scale' near field of a cementitious waste repository. Reduced solute transport is calculated in the repository near field due to porosity and permeability changes at the rock-repository interface. Within the small-scale porous medium approach, coupling of chemical reactions and hydrodynamic parameters indicates a self-sealing barrier at the host rock-repository interface for several scenarios. This barrier might persist for very long times and effectively contain radionuclides within the engineered repository system. Taking into account flow path and barrier-specific heterogeneity will be a further step to improve the understanding of coupled processes in the vicinity of a real cementitious near field.

  18. Are there options for nuclear waste?

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    The problems of storage of nuclear wastes are reaching crisis proportions. Although conceding that a measure of the crises has been caused by the ‘enormous emotion’ of ‘protesting green ecologists,’ (ISR, Interdisciplinary Science Reviews, 5(4), 1980), the bottom line is that nuclear wastes have been and continue to be dumped into the oceans and scattered in leaking and leakable containers on the surface. There is a fear among members of the nuclear engineering community that the U.S., under recent government restrictions, has placed itself in a compromising position on the development of nuclear power facilities. One area of concern is that of nuclear waste disposal. Other countries are subject to the same problems and fears. For example, in the Federal Republic of Germany the term ‘Enstorgungszentrum’ has been coined to describe the total process of reprocessing and disposal of spent nuclear fuel elements. The concern is that spent fuel continues to accumulate because restrictions and laws have affected efforts to resolve the problems of reprocessing and disposal. Right now the environment is subject to damage from the inadequate storage practices of the past. Geoscientists working on the problem of waste disposal await the answers to questions about the projected quantity of waste to be disposed. The options to be explored depend on the volumes to be handled.

  19. Contribution to the French program dedicated to cementitious and clayey materials behavior in the context of Intermediate Level Waste management - Hydrogen transfer and materials durability

    NASA Astrophysics Data System (ADS)

    Bary, B.; Bouniol, P.; Chomat, L.; Dridi, W.; Gatabin, C.; Imbert, C.; L´Hostis, V.; Le Bescop, P.; Muzeau, B.; Poyet, S.

    2013-07-01

    This article illustrates a contribution of the CEA Laboratory of Concrete and Clay Behavior (“LECBA”s) for the assessment and modeling of the Long-Term behavior of cementitious and clayey materials in the context of nuclear ILW (Intermediate Level Waste) management. In particular, we aim at presenting two main topics that are studied at the Lab. The first one is linked to safety aspects and concern hydrogen transfer within cementitious as well as clayey materials (host rock for French nuclear waste disposal). The second point concerns the assessment of durability properties of reinforced concrete structures in the disposal (pre-closure and post-closure) conditions. Experimental specific tests and phenomenological modelling are presented.

  20. Engineering Options Assessment Report: Nitrate Salt Waste Stream Processing

    SciTech Connect

    Anast, Kurt Roy

    2015-11-18

    This report examines and assesses the available systems and facilities considered for carrying out remediation activities on remediated nitrate salt (RNS) and unremediated nitrate salt (UNS) waste containers at Los Alamos National Laboratory (LANL). The assessment includes a review of the waste streams consisting of 60 RNS, 29 aboveground UNS, and 79 candidate belowground UNS containers that may need remediation. The waste stream characteristics were examined along with the proposed treatment options identified in the Options Assessment Report . Two primary approaches were identified in the five candidate treatment options discussed in the Options Assessment Report: zeolite blending and cementation. Systems that could be used at LANL were examined for housing processing operations to remediate the RNS and UNS containers and for their viability to provide repackaging support for remaining LANL legacy waste.

  1. Engineering Options Assessment Report. Nitrate Salt Waste Stream Processing

    SciTech Connect

    Anast, Kurt Roy

    2015-11-13

    This report examines and assesses the available systems and facilities considered for carrying out remediation activities on remediated nitrate salt (RNS) and unremediated nitrate salt (UNS) waste containers at Los Alamos National Laboratory (LANL). The assessment includes a review of the waste streams consisting of 60 RNS, 29 above-ground UNS, and 79 candidate below-ground UNS containers that may need remediation. The waste stream characteristics were examined along with the proposed treatment options identified in the Options Assessment Report . Two primary approaches were identified in the five candidate treatment options discussed in the Options Assessment Report: zeolite blending and cementation. Systems that could be used at LANL were examined for housing processing operations to remediate the RNS and UNS containers and for their viability to provide repackaging support for remaining LANL legacy waste.

  2. Proposed HWIR alters waste treatment, disposal options

    SciTech Connect

    Hill, M.; Robinson, C.

    1996-04-01

    In what it has called its most important change to the hazardous waste rules since 1980, the Environmental Protection Agency has proposed the Hazardous Waste Identification Rule for process wastes that currently are regulated by the hazardous waste provisions in the Resource Conservation and Recovery Act, or RCRA Subtitle C. The rule addresses wastes that EPA has individually listed as hazardous, as well as wastes that are mixed with, derived from or contain listed hazardous wastes. The HWIR sets constituent-specific exit levels that would let low-risk process wastes escape the rigorous regulations of Subtitle C. EPA also proposes changes to RCRA`s land disposal restrictions so that some wastes that currently must be treated according to strict universal treatment standards may not have to be treated at all -- or could be treated in a less expensive manner -- before disposal. The proposed rule is important to virtually every company that is subject to RCRA`s hazardous waste regulations and raises many issues on which companies may want to comment.

  3. Geochemical modeling of leaching of Ca, Mg, Al, and Pb from cementitious waste forms

    SciTech Connect

    Martens, E.; Jacques, D.; Van Gerven, T.; Wang, L.; Mallants, D.

    2010-08-15

    Results from extraction tests on cement-waste samples were simulated with a thermodynamic equilibrium model using a consistent database, to which lead data were added. Subsequent diffusion tests were modeled by means of a 3D diffusive transport model combined with the geochemical model derived from the extraction tests. Modeling results of the leached major element concentrations for both uncarbonated and (partially) carbonated samples agreed well with the extraction test using the set of pure minerals and solid solutions present in the database. The observed decrease in Ca leaching with increasing carbonation level was qualitatively predicted. Simulations also revealed that Pb leaching is not controlled by dissolution/precipitation only. The addition of the calcite-cerrusite solid solution and adsorption reactions on amorphous Fe- and Al-oxides improved the predictions and are considered to control the Pb leaching during the extractions tests. The dynamic diffusive leaching tests were appropriately modeled for Na, K, Ca and Pb.

  4. Hot isostatic press waste option study report

    SciTech Connect

    Russell, N.E.; Taylor, D.D.

    1998-02-01

    A Settlement Agreement between the Department of Energy and the State of Idaho mandates that all high-level radioactive waste now stored at the Idaho Chemical Processing Plant be treated so that it is ready to move out of Idaho for disposal by the target date of 2035. This study investigates the immobilization of all Idaho Chemical Processing Plant calcine, including calcined sodium bearing waste, via the process known as hot isostatic press, which produces compact solid waste forms by means of high temperature and pressure (1,050 C and 20,000 psi), as the treatment method for complying with the settlement agreement. The final waste product would be contained in stainless-steel canisters, the same type used at the Savannah River Site for vitrified waste, and stored at the Idaho National Engineering and Environmental Laboratory until a national geological repository becomes available for its disposal. The waste processing period is from 2013 through 2032, and disposal at the High Level Waste repository will probably begin sometime after 2065.

  5. Modeling of Solid Waste Processing Options in BIO-Plex

    NASA Technical Reports Server (NTRS)

    Rodriguez, Luis F.; Finn, Cory; Kang, Sukwon; Hogan, John; Luna, Bernadette (Technical Monitor)

    2000-01-01

    BIO-Plex is a ground-based test bed currently under development by NASA for testing technologies and practices that may be utilized in future long-term life support missions. All aspects of such an Advanced Life Support (ALS) System must be considered to confidently construct a reliable system, which will not only allow the crew to survive in harsh environments, but allow the crew time to perform meaningful research. Effective handling of solid wastes is a critical aspect of the system, especially when recovery of resources contained in the waste is required. This is particularly important for ALS Systems configurations that include a Biomass Production Chamber. In these cases, significant amounts of inedible biomass waste may be produced, which can ultimately serve as a repository of necessary resources for sustaining life, notably carbon, water, and plant nutrients. Numerous biological and physicochemical solid waste processing options have been considered. Biological options include composting, aerobic digestion, and anaerobic digestion. Physicochemical options include pyrolysis, SCWO (supercritical water oxidation), various incineration configurations, microwave incineration, magnetically assisted gasification, and low temperature plasma reaction. Modeling of these options is a necessary step to assist in the design process. A previously developed top-level model of BIO-Plex implemented in MATLAB Simulink (r) for the use of systems analysis and design has been adopted for this analysis. Presently, this model only considered incineration for solid waste processing. Present work, reported here, includes the expansion of this model to include a wider array of solid waste processing options selected from the above options, bearing in mind potential, near term solid waste treatment systems. Furthermore, a trade study has also been performed among these solid waste processing technologies in an effort to determine the ideal technology for long-term life support

  6. Mixed Waste Management Options: 1995 Update. National Low-Level Waste Management Program

    SciTech Connect

    Kirner, N.; Kelly, J.; Faison, G.; Johnson, D.

    1995-05-01

    In the original mixed Waste Management Options (DOE/LLW-134) issued in December 1991, the question was posed, ``Can mixed waste be managed out of existence?`` That study found that most, but not all, of the Nation`s mixed waste can theoretically be managed out of existence. Four years later, the Nation is still faced with a lack of disposal options for commercially generated mixed waste. However, since publication of the original Mixed Waste Management Options report in 1991, limited disposal capacity and new technologies to treat mixed waste have become available. A more detailed estimate of the Nation`s mixed waste also became available when the US Environmental Protection Agency (EPA) and the US Nuclear Regulatory Commission (NRC) published their comprehensive assessment, titled National Profile on Commercially Generated Low-Level Radioactive Mixed Waste (National Profile). These advancements in our knowledge about mixed waste inventories and generation, coupled with greater treatment and disposal options, lead to a more applied question posed for this updated report: ``Which mixed waste has no treatment option?`` Beyond estimating the volume of mixed waste requiring jointly regulated disposal, this report also provides a general background on the Atomic Energy Act (AEA) and the Resource Conservation and Recovery Act (RCRA). It also presents a methodical approach for generators to use when deciding how to manage their mixed waste. The volume of mixed waste that may require land disposal in a jointly regulated facility each year was estimated through the application of this methodology.

  7. Evaluation of blends bauxite-calcination-method red mud with other industrial wastes as a cementitious material: properties and hydration characteristics.

    PubMed

    Zhang, Na; Liu, Xiaoming; Sun, Henghu; Li, Longtu

    2011-01-15

    Red mud is generated from alumina production, and its disposal is currently a worldwide problem. In China, large quantities of red mud derived from bauxite calcination method are being discharged annually, and its utilization has been an urgent topic. This experimental research was to evaluate the feasibility of blends red mud derived from bauxite calcination method with other industrial wastes for use as a cementitious material. The developed cementitious material containing 30% of the bauxite-calcination-method red mud possessed compressive strength properties at a level similar to normal Portland cement, in the range of 45.3-49.5 MPa. Best compressive strength values were demonstrated by the specimen RSFC2 containing 30% bauxite-calcination-method red mud, 21% blast-furnace slag, 10% fly ash, 30% clinker, 8% gypsum and 1% compound agent. The mechanical and physical properties confirm the usefulness of RSFC2. The hydration characteristics of RSFC2 were characterized by XRD, FTIR, (27)Al MAS-NMR and SEM. As predominant hydration products, ettringite and amorphous C-S-H gel are principally responsible for the strength development of RSFC2. Comparing with the traditional production for ordinary Portland cement, this green technology is easier to be implemented and energy saving. This paper provides a key solution to effectively utilize bauxite-calcination-method red mud. PMID:20932639

  8. Research and Development of a New Silica-Alumina Based Cementitious Material Largely Using Coal Refuse for Mine Backfill, Mine Sealing and Waste Disposal Stabilization

    SciTech Connect

    Henghu Sun; Yuan Yao

    2012-06-29

    Coal refuse and coal combustion byproducts as industrial solid waste stockpiles have become great threats to the environment. To activate coal refuse is one practical solution to recycle this huge amount of solid waste as substitute for Ordinary Portland Cement (OPC). The central goal of this project is to investigate and develop a new silica-alumina based cementitious material largely using coal refuse as a constituent that will be ideal for durable construction, mine backfill, mine sealing and waste disposal stabilization applications. This new material is an environment-friendly alternative to Ordinary Portland Cement. The main constituents of the new material are coal refuse and other coal wastes including coal sludge and coal combustion products (CCPs). Compared with conventional cement production, successful development of this new technology could potentially save energy and reduce greenhouse gas emissions, recycle vast amount of coal wastes, and significantly reduce production cost. A systematic research has been conducted to seek for an optimal solution for enhancing pozzolanic reactivity of the relatively inert solid waste-coal refuse in order to improve the utilization efficiency and economic benefit as a construction and building material.

  9. Chemical fixation increases options for hazardous waste treatment

    SciTech Connect

    Indelicato, G.J.; Tipton, G.A.

    1996-05-01

    The Hazardous and Solid Waste Amendments (HSWA) to the Resource Conservation and Recovery Act (RCRA) govern the manner in which hazardous materials are managed. Disposing RCRA hazardous wastes on or in the land is no longer an accepted remedial option. This land disposal restriction requires that all listed and characteristic hazardous wastes must be treated according to specified standards before they are disposed. These treatment standards define technologies and concentration limits. Hazardous wastes that do not meet the standards are prohibited from being disposed on land, such as in landfills, surface impoundments, land treatment units, injection wells, and mines or caves.

  10. Hanford Waste Vitrification Plant capacity increase options

    SciTech Connect

    Larson, D.E.

    1996-04-01

    Studies are being conducted by the Hanford Waste Vitrification Plant (HWVP) Project on ways to increase the waste processing capacity within the current Vitrification Building structural design. The Phase 1 study on remote systems concepts identification and extent of capacity increase was completed. The study concluded that the HWVP capacity could be increased to four times the current capacity with minor design adjustments to the fixed facility design, and the required design changes would not impact the current footprint of the vitrification building. A further increase in production capacity may be achievable but would require some technology development, verification testing, and a more systematic and extensive engineering evaluation. The primary changes included a single advance melter with a higher capacity, new evaporative feed tank, offgas quench collection tank, ejector venturi scrubbers, and additional inner canister closure station,a smear test station, a new close- coupled analytical facility, waste hold capacity of 400,000 gallon, the ability to concentrate out-of-plant HWVP feed to 90 g/L waste oxide concentration, and limited changes to the current base slab construction package.

  11. Impact assessment of waste management options in Singapore.

    PubMed

    Tan, Reginald B H; Khoo, Hsien H

    2006-03-01

    This paper describes the application of life cycle assessment for evaluating various waste management options in Singapore, a small-island city state. The impact assessment method by SimaPro is carried out for comparing the potential environmental impacts of waste treatment options including landfilling, incineration, recycling, and composting. The inventory data include gases and leachate from landfills, air emissions and energy recovery from incinerators, energy (and emission) savings from recycling, composting gases, and transport pollution. The impact assessment results for climate change, acidification, and ecotoxicity show that the incineration of materials imposes considerable harm to both human health and the environment, especially for the burning of plastics, paper/cardboard, and ferrous metals. The results also show that, although some amount of energy can be derived from the incineration of wastes, these benefits are outweighed by the air pollution (heavy metals and dioxins/furans) that incinerators produce. For Singapore, landfill gases and leachate generate minimal environmental damage because of the nation's policy to landfill only 10% of the total disposed wastes. Land transportation and separation of waste materials also pose minimal environmental damage. However, sea transportation to the landfill could contribute significantly to acidification because of the emissions of sulfur oxides and nitrogen oxides from barges. The composting of horticultural wastes hardly imposes any environmental damage. Out of all the waste strategies, the recycling of wastes offers the best solution for environmental protection and improved human health for the nation. Significant emission savings can be realized through recycling. PMID:16573187

  12. Immobilized low-level waste disposal options configuration study

    SciTech Connect

    Mitchell, D.E.

    1995-02-01

    This report compiles information that supports the eventual conceptual and definitive design of a disposal facility for immobilized low-level waste. The report includes the results of a joint Westinghouse/Fluor Daniel Inc. evaluation of trade-offs for glass manufacturing and product (waste form) disposal. Though recommendations for the preferred manufacturing and disposal option for low-level waste are outside the scope of this document, relative ranking as applied to facility complexity, safety, remote operation concepts and ease of retrieval are addressed.

  13. Cementitious barriers partnership transport properties of damaged materials

    SciTech Connect

    Langton, C.

    2014-11-01

    The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the United States Department of Energy (US DOE) Office of Waste Processing. The objective of the CBP project is to develop 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.

  14. Cementitious Barriers Partnership Scm Paste Samples Exposed To Aggressive Solutions

    SciTech Connect

    Foster, T.

    2014-12-01

    The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the United States Department of Energy (US DOE) Office of Waste Processing. The objective of the CBP project is to develop 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.

  15. An environmental analysis for comparing waste management options and strategies.

    PubMed

    Marchettini, N; Ridolfi, R; Rustici, M

    2007-01-01

    The debate on different waste management practices has become an issue of utmost importance as human activities have overloaded the assimilative capacity of the biosphere. Recent Italian law on solid waste management recommends an increase in material recycling and energy recovery, and only foresees landfill disposal for inert materials and residues from recovery and recycling. A correct waste management policy should be based on the principles of sustainable development, according to which our refuse is not simply regarded as something to eliminate but rather as a potential resource. This requires the creation of an integrated waste management plan that makes full use of all available technologies. In this context, eMergy analysis is applied to evaluate three different forms of waste treatment and construct an approach capable of assessing the whole strategy of waste management. The evaluation included how much investment is needed for each type of waste management and how much "utility" is extracted from wastes, through the use of two indicators: Environmental yield ratio (EYR) and Net eMergy. Our results show that landfill is the worst system in terms of eMergy costs and eMergy benefits. Composting is the most efficient system in recovering eMergy (highest EYR) from municipal solid waste (MSW) while incineration is capable of saving the greatest quantity of eMergy per gram of MSW (highest net eMergy). This analysis has made it possible to assess the sustainability and the efficiency of individual options but could also be used to assess a greater environmental strategy for waste management, considering a system that might include landfills, incineration, composting, etc. PMID:16765586

  16. RADIOACTIVE WASTE STREAMS FROM VARIOUS POTENTIAL NUCLEAR FUEL CYCLE OPTIONS

    SciTech Connect

    Nick Soelberg; Steve Piet

    2010-11-01

    Five fuel cycle options, about which little is known compared to more commonly known options, have been studied in the past year for the United States Department of Energy. These fuel cycle options, and their features relative to uranium-fueled light water reactor (LWR)-based fuel cycles, include: • Advanced once-through reactor concepts (Advanced Once-Through, or AOT) – intended for high uranium utilization and long reactor operating life, use depleted uranium in some cases, and avoid or minimize used fuel reprocessing • Fission-fusion hybrid (FFH) reactor concepts – potential variations are intended for high uranium or thorium utilization, produce fissile material for use in power generating reactors, or transmute transuranic (TRU) and some radioactive fission product (FP) isotopes • High temperature gas reactor (HTGR) concepts - intended for high uranium utilization, high reactor thermal efficiencies; they have unique fuel designs • Molten salt reactor (MSR) concepts – can breed fissile U-233 from Th fuel and avoid or minimize U fuel enrichment, use on-line reprocessing of the used fuel, produce lesser amounts of long-lived, highly radiotoxic TRU elements, and avoid fuel assembly fabrication • Thorium/U-233 fueled LWR (Th/U-233) concepts – can breed fissile U-233 from Th fuel and avoid or minimize U fuel enrichment, and produce lesser amounts of long-lived, highly radiotoxic TRU elements. These fuel cycle options could result in widely different types and amounts of used or spent fuels, spent reactor core materials, and waste streams from used fuel reprocessing, such as: • Highly radioactive, high-burnup used metal, oxide, or inert matrix U and/or Th fuels, clad in Zr, steel, or composite non-metal cladding or coatings • Spent radioactive-contaminated graphite, SiC, carbon-carbon-composite, metal, and Be reactor core materials • Li-Be-F salts containing U, TRU, Th, and fission products • Ranges of separated or un-separated activation

  17. Investigating humic substances interactions with Th4+, UO22+, and NpO2+ at high pH: Relevance to cementitious disposal of radioactive wastes

    NASA Astrophysics Data System (ADS)

    Stockdale, Anthony; Bryan, Nick D.; Lofts, Stephen; Tipping, Edward

    2013-11-01

    A number of geodisposal concepts for intermediate level radioactive waste involve geological emplacement within cementitious repositories. Such facilities, once rehydrated with groundwater, will create high pH environments due to aqueous phase reaction of the cements. This work focuses on the interactions of several important long-lived radionuclide cations with dissolved organic matter (DOM) constituents (humic and fulvic acids) under high pH conditions. We also sought to test the comprehensive speciation model WHAM/Humic Ion Binding Model VII for these specific conditions. Results for Th demonstrate high fractions present as organic complexes at all pH values. Binding of neptunyl to DOM shows a maximum over the pH range expected within an evolving repository. Uranyl exhibits decreasing binding with pH, however, the majority of metal in solution is present as organic complexes under the lower pH conditions investigated (10-10.5). We have updated the WHAM/Model VII binding values for UO22+, and have for the first time added NpO2+ values to the database. These updates now allow application of the model for more complex mixtures across the entire repository pH range. Calculations for three simulated cement interstitial waters (representing different degradation phases) suggest U(VI) and Np(V) are not likely to be significantly bound to DOM under these conditions.

  18. Life cycle assessment of bagasse waste management options

    SciTech Connect

    Kiatkittipong, Worapon; Wongsuchoto, Porntip; Pavasant, Prasert

    2009-05-15

    Bagasse is mostly utilized for steam and power production for domestic sugar mills. There have been a number of alternatives that could well be applied to manage bagasse, such as pulp production, conversion to biogas and electricity production. The selection of proper alternatives depends significantly on the appropriateness of the technology both from the technical and the environmental points of view. This work proposes a simple model based on the application of life cycle assessment (LCA) to evaluate the environmental impacts of various alternatives for dealing with bagasse waste. The environmental aspects of concern included global warming potential, acidification potential, eutrophication potential and photochemical oxidant creation. Four waste management scenarios for bagasse were evaluated: landfilling with utilization of landfill gas, anaerobic digestion with biogas production, incineration for power generation, and pulp production. In landfills, environmental impacts depended significantly on the biogas collection efficiency, whereas incineration of bagasse to electricity in the power plant showed better environmental performance than that of conventional low biogas collection efficiency landfills. Anaerobic digestion of bagasse in a control biogas reactor was superior to the other two energy generation options in all environmental aspects. Although the use of bagasse in pulp mills created relatively high environmental burdens, the results from the LCA revealed that other stages of the life cycle produced relatively small impacts and that this option might be the most environmentally benign alternative.

  19. High durability cementitious material with mineral admixtures and carbonation curing

    SciTech Connect

    Watanabe, K. . E-mail: kenzo@kajima.com; Yokozeki, K.; Ashizawa, R.; Sakata, N.; Morioka, M.; Sakai, E.; Daimon, M.

    2006-07-01

    Nuclear waste repositories need highly durable cementitious materials to function for over thousands of years while resisting leaching and degradation. The durability of cementitious material can be effectively improved by reducing permeability and by changing cement hydrates to a less soluble matrix. This paper describes the properties of carbonated new cementitious materials containing belite-rich cement and {gamma}-2CaO . SiO{sub 2} as main components. In addition, the long-term leaching properties are investigated and compared with ordinary Portland cement by using a predictive leaching model.

  20. ENVIROCARE OF UTAH: EXPANDING WASTE ACCEPTANCE CRITERIA TO PROVIDE LOW-LEVEL AND MIXED WASTE DISPOSAL OPTIONS

    SciTech Connect

    Rogers, B.; Loveland, K.

    2003-02-27

    Envirocare of Utah operates a low-level radioactive waste disposal facility 80 miles west of Salt Lake City in Clive, Utah. Accepted waste types includes NORM, 11e2 byproduct material, Class A low-level waste, and mixed waste. Since 1988, Envirocare has offered disposal options for environmental restoration waste for both government and commercial remediation projects. Annual waste receipts exceed 12 million cubic feet. The waste acceptance criteria (WAC) for the Envirocare facility have significantly expanded to accommodate the changing needs of restoration projects and waste generators since its inception, including acceptable physical waste forms, radiological acceptance criteria, RCRA requirements and treatment capabilities, PCB acceptance, and liquids acceptance. Additionally, there are many packaging, transportation, and waste management options for waste streams acceptable at Envirocare. Many subcontracting vehicles are also available to waste generators for both government and commercial activities.

  1. Test plan: Sealing of the Disturbed Rock Zone (DRZ), including Marker Bed 139 (MB139) and the overlying halite, below the repository horizon, at the Waste Isolation Pilot Plant. [Cementitious grout into fractured WIPP rock

    SciTech Connect

    Ahrens, E.H.

    1992-05-01

    This test plan describes activities intended to demonstrate equipment and techniques for producing, injecting, and evaluating microfine cementitious grout. The grout will be injected in fractured rock located below the repository horizon at the Waste Isolation Pilot Plant (WIPP). These data are intended to support the development of the Alcove Gas Barrier System (AGBS), the design of upcoming, large-scale seal tests, and ongoing laboratory evaluations of grouting efficacy. Degradation of the grout will be studied in experiments conducted in parallel with the underground grouting experiment.

  2. Conceptual waste packaging options for deep borehole disposal

    SciTech Connect

    Su, Jiann -Cherng; Hardin, Ernest L.

    2015-07-01

    -profile threaded connections at each end. The internal-flush design would be suitable for loading waste that arrives from the originating site in weld-sealed, cylindrical canisters. Internal, tapered plugs with sealing filet welds would seal the tubing at each end. The taper would be precisely machined onto both the tubing and the plug, producing a metal-metal sealing surface that is compressed as the package is subjected to hydrostatic pressure. The lower plug would be welded in place before loading, while the upper plug would be placed and welded after loading. Conceptual Waste Packaging Options for Deep Borehole Disposal July 30, 2015 iv Threaded connections between packages would allow emplacement singly or in strings screwed together at the disposal site. For emplacement on a drill string the drill pipe would be connected directly into the top package of a string (using an adapter sub to mate with premium semi-flush tubing threads). Alternatively, for wireline emplacement the same package designs could be emplaced singly using a sub with wireline latch, on the upper end. Threaded connections on the bottom of the lowermost package would allow attachment of a crush box, instrumentation, etc.

  3. Waste reduction options for manufacturers of copper indium diselenide photovoltaic cells

    SciTech Connect

    DePhillips, M.P.; Fthenakis, V.M.; Moskowitz, P.D.

    1994-03-01

    This paper identifies general waste reduction concepts and specific waste reduction options to be used in the production of copper indium diselenide (CIS) photovoltaic cells. A general discussion of manufacturing processes used for the production of photovoltaic cells is followed by a description of the US Environmental Protection Agency (EPA) guidelines for waste reduction (i.e., waste minimization through pollution prevention). A more specific discussion of manufacturing CIS cells is accompanied by detailed suggestions regarding waste minimization options for both inputs and outputs for ten stages of this process. Waste reduction from inputs focuses on source reduction and process changes, and reduction from outputs focuses on material reuse and recycling.

  4. Use of optimization modeling to evaluate industrial waste reduction options: Application to a sour gas plant

    SciTech Connect

    Roberge, H.D. ); Sikora, R.P. ); Baetz, B.W. . Dept. of Civil Engineering)

    1994-01-01

    This note reports on a study of waste reduction options for the upstream oil and gas industry and involves the application of a waste reduction optimization model to a generic sour gas plant. The waste reduction optimization model is meant as an aid for decision-making relating to the implementation of waste reduction options. The generic facility was developed from process knowledge provided by industry members of a project steering committee, as well as waste management information from industry manuals and represents a facility of average capacity and typical configuration. Several waste minimization options were modeled for selected waste streams. The selected streams were chosen based upon waste flows and disposal costs and their potential for waste reduction. The results of the modeling for the generic sour gas plant have shown that a set of cost-effective waste reduction options exist, there is significant potential for reducing the total quantity of waste to be managed and disposed of, and that implementation of the options would lead to considerable cost savings. The value and usefulness of the modeling approach lie not only in the generated results, but also in the fact that to construct the model, relevant waste flows and every possible manner that these waste flows can be minimized or processed are systematically identified. Once modeled, the parameters can be readily manipulated to determine various possible waste management strategies. To effectively use the modeling approach, the waste reduction team should have knowledge of the plant processes, existing waste management practices and costs, information on potential waste reduction options and technologies, as well as experience in mathematical modeling and analysis.

  5. Interpretation of leaching data for cementitious waste forms using analytical solutions based on mass transport theory and empiricism

    SciTech Connect

    Spence, R.D.; Godbee, H.W.; Tallent, O.K.; McDaniel, E.W.; Nestor, C.W.

    1991-01-01

    Despite the demonstrated importance of diffusion control in leaching, other mechanisms have been observed to play a role and leaching from porous solid bodies is not simple diffusion. Only simple diffusion theory has been developed well enough for extrapolation, as yet. The well developed diffusion theory, used in data analysis by ANSI/ANS-16.1 and the NEWBOX program, can help in trying to extrapolate and predict the performance of solidified waste forms over decades and centuries, but the limitations and increased uncertainty must be understood in so doing. Treating leaching as a semi-infinite medium problem, as done in the Cote model, results in simpler equations, but limits, application to early leaching behavior when less than 20% of a given component has been leached. 18 refs., 2 tabs.

  6. Options assessment report: Treatment of nitrate salt waste at Los Alamos National Laboratory

    SciTech Connect

    Robinson, Bruce Alan; Stevens, Patrice Ann

    2015-09-16

    This report documents the methodology used to select a method of treatment for the remediated nitrate salt (RNS) and unremediated nitrate salt (UNS) waste containers at Los Alamos National Laboratory (LANL). The method selected should treat the containerized waste in a manner that renders the waste safe and suitable for transport and final disposal in the Waste Isolation Pilot Plant (WIPP) repository, under specifications listed in the WIPP Waste Acceptance Criteria (DOE/CBFO, 2013). LANL recognized that the results must be thoroughly vetted with the New Mexico Environment Department (NMED) and the a modification to the LANL Hazardous Waste Facility Permit is a necessary step before implementation of this or any treatment option. Likewise, facility readiness and safety basis approvals must be received from the Department of Energy (DOE). This report presents LANL's preferred option, and the documentation of the process for reaching the recommended treatment option for RNS and UNS waste, and is presented for consideration by NMED and DOE.

  7. A multi-criteria decision analysis assessment of waste paper management options

    SciTech Connect

    Hanan, Deirdre; Burnley, Stephen; Cooke, David

    2013-03-15

    Highlights: ► Isolated communities have particular problems in terms of waste management. ► An MCDA tool allowed a group of non-experts to evaluate waste management options. ► The group preferred local waste management solutions to export to the mainland. ► Gasification of paper was the preferred option followed by recycling. ► The group concluded that they could be involved in the decision making process. - Abstract: The use of Multi-criteria Decision Analysis (MCDA) was investigated in an exercise using a panel of local residents and stakeholders to assess the options for managing waste paper on the Isle of Wight. Seven recycling, recovery and disposal options were considered by the panel who evaluated each option against seven environmental, financial and social criteria. The panel preferred options where the waste was managed on the island with gasification and recycling achieving the highest scores. Exporting the waste to the English mainland for incineration or landfill proved to be the least preferred options. This research has demonstrated that MCDA is an effective way of involving community groups in waste management decision making.

  8. 327 Building liquid waste handling options modification project plan

    SciTech Connect

    Ham, J.E.

    1998-03-28

    This report evaluates the modification options for handling radiological liquid waste (RLW) generated during decontamination and cleanout of the 327 Building. The overall objective of the 327 Facility Stabilization Project is to establish a passively safe and environmentally secure configuration of the 327 Facility. The issue of handling of RLW from the 327 Facility (assuming the 34O Facility is not available to accept the RLW) has been conceptually examined in at least two earlier engineering studies (Parsons 1997a and Hobart l997). Each study identified a similar preferred alternative that included modifying the 327 Facility RLWS handling systems to provide a truck load-out station, either within the confines of the facility or exterior to the facility. The alternatives also maximized the use of existing piping, tanks, instrumentation, controls and other features to minimize costs and physical changes. An issue discussed in each study involved the anticipated volume of the RLW stream. Estimates ranged between 113,550 and 387,500 liters in the earlier studies. During the development of the 324/327 Building Stabilization/Deactivation Project Management Plan, the lower estimate of approximately 113,550 liters was confirmed and has been adopted as the baseline for the 327 Facility RLW stream. The goal of this engineering study is to reevaluate the existing preferred alternative and select a new preferred alternative, if appropriate. Based on the new or confirmed preferred alternative, this study will also provide a conceptual design and cost estimate for required modifications to the 327 Facility to allow removal of RLWS and treatment of the RLW generated during deactivation.

  9. Technological options for management of hazardous wastes from US Department of Energy facilities

    SciTech Connect

    Chiu, S.; Newsom, D.; Barisas, S.; Humphrey, J.; Fradkin, L.; Surles, T.

    1982-08-01

    This report provides comprehensive information on the technological options for management of hazardous wastes generated at facilities owned or operated by the US Department of Energy (DOE). These facilities annually generate a large quantity of wastes that could be deemed hazardous under the Resource Conservation and Recovery Act (RCRA). Included in these wastes are liquids or solids containing polychlorinated biphenyls, pesticides, heavy metals, waste oils, spent solvents, acids, bases, carcinogens, and numerous other pollutants. Some of these wastes consist of nonnuclear hazardous chemicals; others are mixed wastes containing radioactive materials and hazardous chemicals. Nearly 20 unit processes and disposal methods are presented in this report. They were selected on the basis of their proven utility in waste management and potential applicability at DOE sites. These technological options fall into five categories: physical processes, chemical processes, waste exchange, fixation, and ultimate disposal. The options can be employed for either resource recovery, waste detoxification, volume reduction, or perpetual storage. Detailed descriptions of each technological option are presented, including information on process performance, cost, energy and environmental considerations, waste management of applications, and potential applications at DOE sites. 131 references, 25 figures, 23 tables.

  10. CEMENTITIOUS BARRIERS PARTNERSHIP ACCOMPLISHMENTS AND RELEVANCE TO THE DOE COMPLEX

    SciTech Connect

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

    2010-11-15

    The Cementitious Barriers Partnership (CBP) was initiated to reduce risk and uncertainties in the performance assessments that directly impact U.S. Department of Energy (DOE) environmental cleanup and closure programs. The CBP is supported by the DOE Office of Environmental Management (DOE-EM) and has been specifically addressing the following critical EM program needs: (i) the long-term performance of cementitious barriers and materials in nuclear waste disposal facilities and (ii) increased understanding of contaminant transport behavior within cementitious barrier systems to support the development and deployment of adequate closure technologies. To accomplish this, the CBP has two initiatives: (1) an experimental initiative to increase understanding of changes in cementitious materials over long times (> 1000 years) over changing conditions and (2) a modeling initiative to enhance and integrate a set of computational tools validated by laboratory and field experimental data to improve understanding and prediction of the long-term performance of cementitious barriers and waste forms used in nuclear applications. In FY10, the CBP developed the initial phase of an integrated modeling tool that would serve as a screening tool which could help in making decisions concerning disposal and tank closure. The CBP experimental programs are underway to validate this tool and provide increased understanding of how CM changes over time and under changing conditions. These initial CBP products that will eventually be enhanced are anticipated to reduce the uncertainties of current methodologies for assessing cementitious barrier performance and increase the consistency and transparency of the DOE assessment process. These tools have application to low activity waste forms, high level waste tank closure, D&D and entombment of major nuclear facilities, landfill waste acceptance criteria, and in-situ grouting and immobilization of vadose zone contamination. This paper summarizes

  11. Alternative disposal options for alpha-mixed low-level waste

    SciTech Connect

    Loomis, G.G.; Sherick, M.J.

    1995-12-01

    This paper presents several disposal options for the Department of Energy alpha-mixed low-level waste. The mixed nature of the waste favors thermally treating the waste to either an iron-enriched basalt or glass waste form, at which point a multitude of reasonable disposal options, including in-state disposal, are a possibility. Most notably, these waste forms will meet the land-ban restrictions. However, the thermal treatment of this waste involves considerable waste handling and complicated/expensive offgas systems with secondary waste management problems. In the United States, public perception of offgas systems in the radioactive incinerator area is unfavorable. The alternatives presented here are nonthermal in nature and involve homogenizing the waste with cryogenic techniques followed by complete encapsulation with a variety of chemical/grouting agents into retrievable waste forms. Once encapsulated, the waste forms are suitable for transport out of the state or for actual in-state disposal. This paper investigates variances that would have to be obtained and contrasts the alternative encapsulation idea with the thermal treatment option.

  12. Alternative disposal options for alpha-mixed low-level waste

    SciTech Connect

    Loomis, G.G.; Sherick, M.J.

    1995-12-31

    This paper presents several disposal options for the Department of Energy alpha-mixed low-level waste. The mixed nature of the waste favors thermally treating the waste to either an iron-enriched basalt or glass waste form, at which point a multitude of reasonable disposal options, including in-state disposal, are a possibility. Most notably, these waste forms will meet the land-ban restrictions. However, the thermal treatment of this waste involves considerable waste handling and complicated/expensive offgas, systems with secondary waste management problems. In the United States, public perception of off gas systems in the radioactive incinerator area is unfavorable. The alternatives presented here are nonthermal in nature and involve homogenizing the waste with cryogenic techniques followed by complete encapsulation with a variety of chemical/grouting agents into retrievable waste forms. Once encapsulated, the waste forms are suitable for transport out of the state or for actual in-state disposal. This paper investigates variances that would have to be obtained and contrasts the alternative encapsulation idea with the thermal treatment option.

  13. Modelling approach to LILW-SL repository safety evaluation for different waste packing options

    SciTech Connect

    Perko, Janez; Mallants, Dirk; Volckaert, Geert; Towler, George; Egan, Mike; Virsek, Sandi; Hertl, Bojan

    2007-07-01

    The key objective of the work described here was to support the identification of a preferred disposal concept and packaging option for low and short-lived intermediate level waste (LILW-SL). The emphasis of the assessment, conducted on behalf of the Slovenian radioactive waste management agency (ARAO), was the consideration of several waste treatment and packaging options in an attempt to identify optimised containment characteristics that would result in safe disposal, taking into account the cost-benefit of alternative safety measures. Waste streams for which alternative treatment and packaging solutions were developed and evaluated include decommissioning waste and NPP operational wastes, including drums with unconditioned ion exchange resins in over-packed tube type containers (TTCs). For decommissioning wastes, the disposal options under consideration were either direct disposal of loose pieces grouted into a vault or use of high integrity containers (HIC). In relation to operational wastes, three main options were foreseen. The first is over-packing of resin containing TTCs grouted into high integrity containers, the second option is complete treatment with hydration, neutralization, and cementation of the dry resins into drums grouted into high integrity containers and the third is direct disposal of TTCs into high integrity containers without additional treatment. The long-term safety of radioactive waste repositories is usually demonstrated with the support of a safety assessment. This normally includes modelling of radionuclide release from a multi-barrier near-surface or deep repository to the geosphere and biosphere. For the current work, performance assessment models were developed for each combination of siting option, repository design and waste packaging option. Modelling of releases from the engineered containment system (the 'near-field') was undertaken using the AMBER code. Detailed unsaturated water flow modelling was undertaken using the

  14. REFERENCE CASES FOR USE IN THE CEMENTITIOUS BARRIERS PARTNERSHIP

    SciTech Connect

    Langton, C

    2009-01-06

    The Cementitious Barriers Project (CBP) is a multidisciplinary cross cutting project initiated by the US Department of Energy (DOE) to develop a reasonable and credible set of tools to improve understanding and prediction of the structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. The period of performance is >100 years for operating facilities and > 1000 years for waste management. The CBP has defined a set of reference cases to provide the following functions: (1) a common set of system configurations to illustrate the methods and tools developed by the CBP, (2) a common basis for evaluating methodology for uncertainty characterization, (3) a common set of cases to develop a complete set of parameter and changes in parameters as a function of time and changing conditions, and (4) a basis for experiments and model validation, and (5) a basis for improving conceptual models and reducing model uncertainties. These reference cases include the following two reference disposal units and a reference storage unit: (1) a cementitious low activity waste form in a reinforced concrete disposal vault, (2) a concrete vault containing a steel high-level waste tank filled with grout (closed high-level waste tank), and (3) a spent nuclear fuel basin during operation. Each case provides a different set of desired performance characteristics and interfaces between materials and with the environment. Examples of concretes, grout fills and a cementitious waste form are identified for the relevant reference case configurations.

  15. Environmental and economic analyses of waste disposal options for traditional markets in Indonesia

    SciTech Connect

    Aye, Lu . E-mail: lua@unimelb.edu.au; Widjaya, E.R.

    2006-07-01

    Waste from traditional markets in Indonesia is the second largest stream of municipal solid waste after household waste. It has a higher organic fraction and may have greater potential to be managed on a business scale compared to household wastes. The attributed reason is that in general the wastes generated from traditional markets are more uniform, more concentrated and less hazardous than waste from other sources. This paper presents the results of environmental and economic assessments to compare the options available for traditional market waste disposal in Indonesia. The options compared were composting in labour intensive plants, composting in a centralised plant that utilised a simple wheel loader, centralised biogas production and landfill for electricity production. The current open dumping practice was included as the baseline case. A life cycle assessment (LCA) was used for environmental analysis. All options compared have lower environmental impacts than the current practice of open dumping. The biogas production option has the lowest environmental impacts. A cost-benefit analysis, which considered greenhouse gas savings, was used for the economic assessment. It was found that composting at a centralised plant is the most economically feasible option under the present Indonesian conditions. The approach reported in this study could be applied for 'a pre-feasibility first cut comparison' that includes environmental aspects in a decision-making framework for developing countries even though European emission factors were used.

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

    SciTech Connect

    Flach, G.P.; Burns, H.H.; Langton, C.; Smith, F.G. III; Brown, K.G.; Kosson, D.S.; Garrabrants, A.C.; Sarkar, S.; Van der Sloot, H.; Meeussen, J.C.L.; Samson, E.; Mallick, P.; Suttora, L.; Esh, D.W.; Fuhrmann, M.J.; Philip, J.

    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 to 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

  17. The Cementitious Barriers Partnership (CBP) Software Toolbox Capabilities In Assessing The Degradation Of Cementitious Barriers

    SciTech Connect

    Flach, G. P.; Burns, H. H.; Langton, C.; Smith, F. G. III; Brown, K. G.; Kosson, D. S.; Garrabrants, A. C.; Sarkar, S.; van der Sloot, H.; Meeussen, J. C.L.; Samson, E.; Mallick, P.; Suttora, L.; Esh, D. W.; Fuhrmann, M. J.; Philip, J.

    2013-01-11

    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 to 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 Kd/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

  18. Landfill area estimation based on integrated waste disposal options and solid waste forecasting using modified ANFIS model.

    PubMed

    Younes, Mohammad K; Nopiah, Z M; Basri, N E Ahmad; Basri, H; Abushammala, Mohammed F M; Younes, Mohammed Y

    2016-09-01

    Solid waste prediction is crucial for sustainable solid waste management. The collection of accurate waste data records is challenging in developing countries. Solid waste generation is usually correlated with economic, demographic and social factors. However, these factors are not constant due to population and economic growth. The objective of this research is to minimize the land requirements for solid waste disposal for implementation of the Malaysian vision of waste disposal options. This goal has been previously achieved by integrating the solid waste forecasting model, waste composition and the Malaysian vision. The modified adaptive neural fuzzy inference system (MANFIS) was employed to develop a solid waste prediction model and search for the optimum input factors. The performance of the model was evaluated using the root mean square error (RMSE) and the coefficient of determination (R(2)). The model validation results are as follows: RMSE for training=0.2678, RMSE for testing=3.9860 and R(2)=0.99. Implementation of the Malaysian vision for waste disposal options can minimize the land requirements for waste disposal by up to 43%. PMID:26522806

  19. Emergy analysis of the recycling options for construction and demolition waste.

    PubMed

    Yuan, Fang; Shen, Li-yin; Li, Qi-ming

    2011-12-01

    Construction and demolition (C&D) waste is becoming a major contributor to environmental pollution. In Shanghai, China, the quantity of C&D waste is 2.11E+07 t/yr, which accounts for 45% of the total quantity of solid waste. There has been a growing promotion of recycling C&D waste as an effective way to solve this waste problem. However, the evaluation of the efficiency of recycling C&D waste as a potential source of resources is largely based on traditional economic analysis. The economic analysis emphasizes money instead of the harmony between economic benefit and environmental effects. There is a need for a new strategic approach to investigate the efficiency of recycling C&D waste to achieve the integration between economic, social and environmental effects. Emergy theory can be employed to analyze different recycling options for C&D waste. With reference to the Chinese construction industry, this paper demonstrates that the close-loop recycling option is better than the open-loop recycling option for C&D waste in terms of the integration of social, environmental and sustainable aspects. To evaluate different technology solutions for C&D waste recycling, the emergy theory and method is not limited to a cost-benefit balance but can include economic, social, environmental and sustainable effects. PMID:21820302

  20. Options and cost for disposal of NORM waste.

    SciTech Connect

    Veil, J. A.

    1998-10-22

    Oil field waste containing naturally occurring radioactive material (NORM) is presently disposed of both on the lease site and at off-site commercial disposal facilities. The majority of NORM waste is disposed of through underground injection, most of which presently takes place at a commercial injection facility located in eastern Texas. Several companies offer the service of coming to an operator's site, grinding the NORM waste into a fine particle size, slurrying the waste, and injecting it into the operator's own disposal well. One company is developing a process whereby the radionuclides are dissolved out of the NORM wastes, leaving a nonhazardous oil field waste and a contaminated liquid stream that is injected into the operator's own injection well. Smaller quantities of NORM are disposed of through burial in landfills, encapsulation inside the casing of wells that are being plugged and abandoned, or land spreading. It is difficult to quantify the total cost for disposing of NORM waste. The cost components that must be considered, in addition to the cost of the operation, include analytical costs, transportation costs, container decontamination costs, permitting costs, and long-term liability costs. Current NORM waste disposal costs range from $15/bbl to $420/bbl.

  1. Study of investigation-derived waste management options. Master's thesis

    SciTech Connect

    Mountain, B.C.

    1993-09-01

    USAF is dedicated to the clean up of past releases of hazardous substances at its bases under the Installation Restoration Program (IRP) . Clean up decisions are based upon data produced from investigations. Large amounts of waste may be derived from investigations. Investigation-derived waste (IDW), especially that with a hazardous component, may pose significant health protection and regulatory compliance problems if neglected. This study identifies the status and the need for improvement of IDW management to avoid those problems. Information on the background of IDW management was collected through a review of environmental laws, waste management regulations, and existing guidance. Practical IDW management information was gleaned from conversations with iRP managers at twelve USAF bases around the country. This study revealed that IDW management needs improvement. All bases acknowledged IDW concerns and have adopted various methods to deal with them. However, current methods appear to rely more upon expediency rather than permanence. This study showed that critical protection and compliance issues are being overlooked. Development of specific IDW management guidance may better assure that critical issues are addressed. Waste minimization, Waste management, Environmental management, Nonhazardous wastes, Hazardous material, Solid wastes.

  2. Analysis of options for coal combustion waste management in the Pacific Basin

    SciTech Connect

    Elcock, D.; Gasper, J.

    1993-10-01

    Many Pacific Basin countries rely on oil for electricity production. Alternative fuel sources such as coal, which is available in the Pacific Basin, can help mitigate adverse impacts of sudden price increases or supply disruptions. Coal combustion produces solid and potentially hazardous wastes of concern to environmental regulators and utility managers. This paper identifies issues associated with managing coal combustion wastes in the Pacific Basin, using the state of Hawaii as a case study. Hawaii is typical of many Pacific Basin locations in that it depends on oil, has limited sites, for waste management operations, and is subject to domestic and international waste management regulations. The paper discusses coal-fired utility wastes, environmental impacts of coal combustion waste disposal, and regulatory requirements that impact coal waste management. From this baseline, potential on- and off-island options for coal waste management are identified. Waste management costs are estimated and non-quantifiable issues are addressed for each option. Many options are applicable across the Pacific Rim and may serve as a basis for future fuel-use decisions.

  3. Anaerobic digestion as a waste disposal option for American Samoa

    SciTech Connect

    Rivard, C

    1993-01-01

    Tuna sludge and municipal solid waste (MSW) generated on Tutuila Island, American Samoa, represent an ongoing disposal problem as well as an emerging opportunity for use in renewable fuel production. This research project focuses on the biological conversion of the organic fraction of these wastes to useful products including methane and fertilizer-grade residue through anaerobic high solids digestion. In this preliminary study, the anaerobic bioconversion of tuna sludge with MSW appears promising.

  4. Ultrafine cementitious grout

    SciTech Connect

    Ahrens, Ernst H.

    1998-01-01

    An ultrafine cementitious grout having a particle size 90% of which are less than 6 .mu.m in diameter and an average size of about 2.5 .mu.m or less, and preferably 90% of which are less than 5 .mu.m in diameter and an average size of about 2 .mu.m or less containing Portland cement, pumice as a pozzolanic material and superplasticizer in the amounts of about 40 wt. % to about 50 wt. % Portland cement; from about 50 wt. % to about 60 wt. % pumice containing at least 60% amorphous silicon dioxide; and from 0.1 wt. % to about 1.5 wt. % superplasticizer. The grout is mixed with water in the W/CM ratio of about 0.4-0.6/1. The grout has very high strength and very low permeability with good workability. The ultrafine particle sizes allow for sealing of microfractures below 10 .mu.m in width.

  5. Ultrafine cementitious grout

    SciTech Connect

    Ahrens, Ernst H.

    1999-01-01

    An ultrafine cementitious grout in three particle grades containing Portland cement, pumice as a pozzolanic material and superplasticizer in the amounts of about 30 wt. % to about 70 wt. % Portland cement; from about 30 wt. % to about 70 wt. % pumice containing at least 70% amorphous silicon dioxide; and from 1.2 wt. % to about 5.0 wt. % superplasticizer. The superplasticizer is dispersed in the mixing water prior to the addition of dry grout and the W/CM ratio is about 0.4 to 1/1. The grout has very high strength and very low permeability with good workability. The ultrafine particle sizes allow for sealing of microfractures below 10 .mu.m in width.

  6. Ultrafine cementitious grout

    SciTech Connect

    Ahrens, E.H.

    1999-10-19

    An ultrafine cementitious grout in three particle grades containing Portland cement, pumice as a pozzolanic material and superplasticizer in the amounts of about 30 wt. % to about 70 wt. % Portland cement; from about 30 wt. % to about 70 wt. % pumice containing at least 70% amorphous silicon dioxide; and from 1.2 wt. % to about 5.0 wt. % superplasticizer. The superplasticizer is dispersed in the mixing water prior to the addition of dry grout and the W/CM ratio is about 0.4 to 1/1. The grout has very high strength and very low permeability with good workability. The ultrafine particle sizes allow for sealing of microfractures below 10 {mu}m in width.

  7. Non-deposit system option for waste management on small islands.

    PubMed

    Vilms, Monica; Voronova, Viktoria

    2016-08-01

    This paper analyses waste management on small islands (on a global scale these are micro-islands). In the context of the paper, small islands are islands that have an area less than 50 km(2) The study presents an overview of the problems connected with waste transport from islands to the mainland. Waste generation on islands is very much related to tourists. If tourists do not handle waste properly, it will cause problems. Four small Estonian islands in the range of 3-19 km(2) are studied in detail. For these and other small islands, the main problem is the waste produced by tourists, or related to tourists and waste transport to the mainland. Currently, the local municipality has to arrange and finance waste transport. In fact, and based on the polluter-pays principle, the tourists should bear the cost of waste management. There are different tax options available in order to collect the money from tourists - waste tax, harbour tax, tourist tax, donations, environmental tax and others. The study results revealed that the best possible solution for Estonian islands may be a non-deposit system - including an additional charge on ferry ticket prices. The extra money should cover the costs of waste management and waste shipping. The tourists arriving in their own boats should pay a harbour tax, which includes a waste tax to compensate for the cost of waste management. PMID:27344037

  8. Options Assessment Report: Treatment of Nitrate Salt Waste at Los Alamos National Laboratory

    SciTech Connect

    Robinson, Bruce Alan; Stevens, Patrice Ann

    2015-12-17

    This report documents the methodology used to select a method of treatment for the remediated nitrate salt (RNS) and unremediated nitrate salt (UNS) waste containers at Los Alamos National Laboratory (LANL). The method selected should treat the containerized waste in a manner that renders the waste safe and suitable for transport and final disposal in the Waste Isolation Pilot Plant (WIPP) repository, under specifications listed in the WIPP Waste Acceptance Criteria (DOE/CBFO, 2013). LANL recognizes that the results must be thoroughly vetted with the New Mexico Environment Department (NMED) and that a modification to the LANL Hazardous Waste Facility Permit is a necessary step before implementation of this or any treatment option. Likewise, facility readiness and safety basis approvals must be received from the Department of Energy (DOE). This report presents LANL’s preferred option, and the documentation of the process for reaching the recommended treatment option for RNS and UNS waste, and is presented for consideration by NMED and DOE.

  9. Waste management options to reduce greenhouse gas emissions from paper in Australia

    NASA Astrophysics Data System (ADS)

    Pickin, J. G.; Yuen, S. T. S.; Hennings, H.

    A lifecycle assessment to estimate greenhouse gas emissions in Australia from the paper cycle is summarised. The greenhouse gas emissions from paper in Australia in 1999/2000 were estimated to be 12.1 million tonnes (Mt) of CO 2 equivalent. Nearly half of this amount consisted of CH 4 emissions from landfilled waste paper. Various waste management options were modelled to investigate the greenhouse impact of a tonne of paper over its whole lifecycle. Options that keep paper out of landfills significantly reduce greenhouse emissions, waste-to-energy recovery being most effective. Recycling is also beneficial, and is of particular interest from a management perspective because it can be controlled by the pulp and paper industry. These findings can be extended to other wood-based and organic wastes.

  10. Evaluation of flammable gas monitoring options for waste tank intrusive activities

    SciTech Connect

    Shultz, M.V.

    1996-09-03

    This calc note documents an evaluation of three options for monitoring hydrogen during waste tank intrusive activities. The three options are (1) one Combustible Gas Monitor with an operator monitoring the readout, (2) two CGMs with separate operators monitoring each gas monitor, and (3) one CGM with audible alarm, no dedicated operator monitoring readout. A comparison of the failure probabilities of the three options is provided. This Calculation Note supports the Flammable Gas Analysis for TWRS FSAR and BIO. This document is not to be used as the sole basis to authorize activities or to change authorization, safety or design bases.

  11. Waste Management Options for Long-Duration Space Missions: When to Reject, Reuse, or Recycle

    NASA Technical Reports Server (NTRS)

    Linne, Diane L.; Palaszewski, Bryan A.; Gokoglu, Suleyman; Gallo, Christopher A.; Balasubramaniam, Ramaswamy; Hegde, Uday G.

    2014-01-01

    The amount of waste generated on long-duration space missions away from Earth orbit creates the daunting challenge of how to manage the waste through reuse, rejection, or recycle. The option to merely dispose of the solid waste through an airlock to space was studied for both Earth-moon libration point missions and crewed Mars missions. Although the unique dynamic characteristics of an orbit around L2 might allow some discarded waste to intersect the lunar surface before re-impacting the spacecraft, the large amount of waste needed to be managed and potential hazards associated with volatiles recondensing on the spacecraft surfaces make this option problematic. A second option evaluated is to process the waste into useful gases to be either vented to space or used in various propulsion systems. These propellants could then be used to provide the yearly station-keeping needs at an L2 orbit, or if processed into oxygen and methane propellants, could be used to augment science exploration by enabling lunar mini landers to the far side of the moon.

  12. Shale: an overlooked option for US nuclear waste disposal

    USGS Publications Warehouse

    Neuzil, Christopher E.

    2014-01-01

    Toss a dart at a map of the United States and, more often than not, it will land where shale can be found underground. A drab, relatively featureless sedimentary rock that historically attracted little interest, shale (as used here, the term includes clay and a range of clay-rich rocks) is entering Americans’ consciousness as a new source of gas and oil. But shale may also offer something entirely different—the ability to safely and permanently house high-level nuclear waste.

  13. Effects of Iron Oxides on the Rheological Properties of Cementitious Slurry

    SciTech Connect

    Chung, Chul-Woo; Chun, Jaehun; Wang, Guohui; Um, Wooyong

    2014-04-02

    Iron oxide has been considered a promising host for immobilizing and encapsulating radioactive 99Tc (t1/2=2.1x105 year), which significantly enhances the stability of 99Tc within a cementitious waste form. However, the flow behavior of cementitious slurry containing iron oxide has never been investigated to ensure its workability, which directly influences the preparation and performance of the cementitious waste form monolith. Variation in the rheological properties of the cementitious slurry were studied using rheometry and ultrasonic wave reflection to understand the effects of various iron oxides (magnetite, hematite, ferrihydrite, and goethite) during the cement setting and stiffening processes. The rheological behavior significantly varied with the addition of different chemical compounds of iron oxides. Complementary microscopic characteristics such as colloidal vibration currents, morphology, and particle size distributions further suggest that the most adverse alteration of cement setting and stiffening behavior caused by the presence of goethite may be attributed to its acicular shape.

  14. Ultrafine cementitious grout

    DOEpatents

    Ahrens, E.H.

    1998-07-07

    An ultrafine cementitious grout is described having a particle size 90% of which are less than 6 {micro}m in diameter and an average size of about 2.5 {micro}m or less, and preferably 90% of which are less than 5 {micro}m in diameter and an average size of about 2 {micro}m or less containing Portland cement, pumice as a pozzolanic material and superplasticizer in the amounts of about 40 wt. % to about 50 wt. % Portland cement; from about 50 wt. % to about 60 wt. % pumice containing at least 60% amorphous silicon dioxide; and from 0.1 wt. % to about 1.5 wt. % superplasticizer. The grout is mixed with water in the W/CM ratio of about 0.4--0.6/1. The grout has very high strength and very low permeability with good workability. The ultrafine particle sizes allow for sealing of microfractures below 10 {micro}m in width. 4 figs.

  15. Evaluating greenhouse gas impacts of organic waste management options using life cycle assessment.

    PubMed

    Kong, Dung; Shan, Jilei; Iacoboni, Mario; Maguin, Stephen R

    2012-08-01

    Efforts to divert organics away from landfills are viewed by many as an important measure to significantly reduce the climate change impacts of municipal solid waste management. However, the actual greenhouse gas (GHG) impacts of organics diversion from landfills have yet to be thoroughly evaluated and whether such a diversion provides significant environmental benefits in terms of GHG impacts must be answered. This study, using California-specific information, aimed to analyse the GHG impacts of organics diversion through a life-cycle assessment (LCA). This LCA considered all aspects of organics management including transportation, materials handling, GHG emissions, landfill gas capture/utilization, energy impacts, and carbon sequestration. The LCA study evaluated overall GHG impacts of landfilling, and alternative management options such as composting and anaerobic digestion for diverted organic waste. The LCA analysis resulted in net GHG reductions of 0.093, 0.048, 0.065 and 0.073 tonnes carbon equivalent per tonne organic waste for landfilling, windrow composting, aerated static pile composting, and anaerobic digestion, respectively. This study confirms that all three options for organics management result in net reductions of GHG emissions, but it also shows that organics landfilling, when well-managed, generates greater GHG reductions. The LCA provides scientific insight with regards to the environmental impacts of organics management options, which should be considered in decision and policy-making. The study also highlights the importance of how site and case-specific conditions influence project outcomes when considering organic waste management options. PMID:22588112

  16. Commercial disposal options for Idaho National Engineering Laboratory low-level radioactive waste

    SciTech Connect

    Porter, C.L.; Widmayer, D.A.

    1995-09-01

    The Idaho National Engineering Laboratory (INEL) is a Department of Energy (DOE)-owned, contractor-operated site. Significant quantities of low-level radioactive waste (LLW) have been generated and disposed of onsite at the Radioactive Waste Management Complex (RWMC). The INEL expects to continue generating LLW while performing its mission and as aging facilities are decommissioned. An on-going Performance Assessment process for the RWMC underscores the potential for reduced or limited LLW disposal capacity at the existing onsite facility. In order to properly manage the anticipated amount of LLW, the INEL is investigating various disposal options. These options include building a new facility, disposing the LLW at other DOE sites, using commercial disposal facilities, or seeking a combination of options. This evaluation reports on the feasibility of using commercial disposal facilities.

  17. Nuclear Waste Vitrification in the U.S.: Recent Developments and Future Options

    SciTech Connect

    Vienna, John D.

    2010-06-23

    Nuclear power plays a key role in maintaining current world wide energy growth while minimizing the greenhouse gas emissions. A disposition path for used nuclear fuel (UNF) must be found for this technology to achieve its promise. One likely option is the recycling of UNF and immobilization of the high-level waste (HLW) by vitrification. Vitrification is the technology of choice for immobilizing HLW from defense and commercial fuel reprocessing around the world. Recent advances in both recycling technology and vitrification show great promise in closing the nuclear fuel cycle in an efficient and economical fashion. This article summarizes the recent trends developments and future options in waste vitrification for both defense waste cleanup and closing the nuclear fuel cycle in the U.S.

  18. A choice experiment analysis for solid waste disposal option: a case study in Malaysia.

    PubMed

    Pek, Chuen-Khee; Jamal, Othman

    2011-11-01

    In Malaysia, most municipal wastes currently are disposed into poorly managed 'controlled tipping' systems with little or no pollution protection measures. This study was undertaken to assist the relevant governmental bodies and service providers to identify an improved waste disposal management strategy. The study applied the choice experiment technique to estimate the nonmarket values for a number of waste disposal technologies. Implicit prices for environmental attributes such as psychological fear, land use, air pollution, and river water quality were estimated. Compensating surplus estimates incorporating distance from the residences of the respondents to the proposed disposal facility were calculated for a number of generic and technology-specific choice sets. The resulting estimates were higher for technology-specific options, and the distance factor was a significant determinant in setting an equitable solid waste management fee. PMID:21820795

  19. Organic fraction of municipal solid waste from mechanical selection: biological stabilization and recovery options.

    PubMed

    Cesaro, Alessandra; Russo, Lara; Farina, Anna; Belgiorno, Vincenzo

    2016-01-01

    Although current trends address towards prevention strategies, the organic fraction of municipal solid waste is greatly produced, especially in high-income contexts. Its recovery-oriented collection is a common practice, but a relevant portion of the biodegradable waste is not source selected. Mechanical and biological treatments (MBT) are the most common option to sort and stabilize the biodegradable matter ending in residual waste stream. Following the changes of the framework around waste management, this paper aimed at analyzing the quality of the mechanically selected organic waste produced in MBT plants, in order to discuss its recovery options. The material performance was obtained by its composition as well as by its main chemical and physical parameters; biological stability was also assessed by both aerobic and anaerobic methods. On this basis, the effectiveness of an aerobic biostabilization process was assessed at pilot scale. After 21 days of treatment, results proved that the biomass had reached an acceptable biostabilization level, with a potential Dynamic Respirometric Index (DRIP) value lower than the limit required for its use as daily or final landfill cover material. However, the final stabilization level was seen to be influenced by scaling factors and the 21 days of treatment turned to be not so adequate when applied in the existing full-scale facility. PMID:26377969

  20. Rheological characterization of cementitious grouts used to dispose of intermediate-level radioactive waste by hydrofracturing at Oak Ridge National Laboratory

    SciTech Connect

    McDaniel, E.W.; Moore, J.G.

    1981-01-01

    The hydrofracturing process is a waste disposal process in use at the Oak Ridge National Laboratory for the permanent disposal of locally generated waste solutions. This process is now being modified for use in the disposal of sludge that results from the sodium hydroxide neutralization of acid waste solutions. In this process, the sludges will be slurried in a bentonite clay suspension and mixed with a solids blend of cement and other additives. The amount of dry solids required for each liter of waste slurry will be determined from a rheogram that relates the viscosity of the slurry with the grams per liter recommended for grouts with desirable flow properties. A description of the process and the development of rheograms are included. Data are presented on the use of chemical additives to control the flow properties of grouts.

  1. Life cycle analysis of management options for organic waste collected in an urban area.

    PubMed

    Di Maria, Francesco; Micale, Caterina

    2015-01-01

    Different options for managing the organic fraction (OF) of municipal solid waste generated in a given urban area were analyzed by life cycle assessment (LCA) for different source segregation (SS) intensities ranging from 0 to 52%. The best management option for processing the OF remaining in the residual organic fraction (ROF) for the different SS intensities was by incineration. Landfilling and mechanical biological treatment (MBT) of ROF gave higher impacts. Aerobic treatment alone or combined with anaerobic digestion (AD) for processing the source-segregated organic fraction (SSOF) led to relevant environmental impact reduction even if the difference between the two options was quite negligible. The weighted impact showed that scenarios using incineration always gave environmental gains, whereas there was a higher environmental burden with the scenarios using MBT. PMID:25060312

  2. Waste heat recovery options in a large gas-turbine combined power plant

    NASA Astrophysics Data System (ADS)

    Upathumchard, Ularee

    This study focuses on power plant heat loss and how to utilize the waste heat in energy recovery systems in order to increase the overall power plant efficiency. The case study of this research is a 700-MW natural gas combined cycle power plant, located in a suburban area of Thailand. An analysis of the heat loss of the combustion process, power generation process, lubrication system, and cooling system has been conducted to evaluate waste heat recovery options. The design of the waste heat recovery options depends to the amount of heat loss from each system and its temperature. Feasible waste heat sources are combustion turbine (CT) room ventilation air and lubrication oil return from the power plant. The following options are being considered in this research: absorption chillers for cooling with working fluids Ammonia-Water and Water-Lithium Bromide (in comparison) and Organic Rankine Cycle (ORC) with working fluids R134a and R245fa. The absorption cycles are modeled in three different stages; single-effect, double-effect and half-effect. ORC models used are simple ORC as a baseline, ORC with internal regenerator, ORC two-phase flash expansion ORC and ORC with multiple heat sources. Thermodynamic models are generated and each system is simulated using Engineering Equation Solver (EES) to define the most suitable waste heat recovery options for the power plant. The result will be synthesized and evaluated with respect to exergy utilization efficiency referred as the Second Law effectiveness and net output capacity. Results of the models give recommendation to install a baseline ORC of R134a and a double-effect water-lithium bromide absorption chiller, driven by ventilation air from combustion turbine compartment. The two technologies yield reasonable economic payback periods of 4.6 years and 0.7 years, respectively. The fact that this selected power plant is in its early stage of operation allows both models to economically and effectively perform waste heat

  3. Haiti: Feasibility of Waste-to-Energy Options at the Trutier Waste Site

    SciTech Connect

    Conrad, M. D.; Hunsberger, R.; Ness, J. E.; Harris, T.; Raibley, T.; Ursillo, P.

    2014-08-01

    This report provides further analysis of the feasibility of a waste-to-energy (WTE) facility in the area near Port-au-Prince, Haiti. NREL's previous analysis and reports identified anaerobic digestion (AD) as the optimal WTE technology at the facility. Building on the prior analyses, this report evaluates the conceptual financial and technical viability of implementing a combined waste management and electrical power production strategy by constructing a WTE facility at the existing Trutier waste site north of Port-au-Prince.

  4. Electrochemical migration technique to accelerate ageing of cementitious materials

    NASA Astrophysics Data System (ADS)

    Babaahmadi, A.; Tang, L.; Abbas, Z.

    2013-07-01

    Durability assessment of concrete structures for constructions in nuclear waste repositories requires long term service life predictions. As deposition of low and intermediate level radioactive waste (LILW) takes up to 100 000 years, it is necessary to analyze the service life of cementitious materials in this time perspective. Using acceleration methods producing aged specimens would decrease the need of extrapolating short term data sets. Laboratory methods are therefore, needed for accelerating the ageing process without making any influencing distortion in the properties of the materials. This paper presents an electro-chemical migration method to increase the rate of calcium leaching from cementitious specimens. This method is developed based on the fact that major long term deterioration process of hardened cement paste in concrete structures for deposition of LILW is due to slow diffusion of calcium ions. In this method the cementitious specimen is placed in an electrochemical cell as a porous path way through which ions can migrate at a rate far higher than diffusion process. The electrical field is applied to the cell in a way to accelerate the ion migration without making destructions in the specimen's micro and macroscopic properties. The anolyte and catholyte solutions are designed favoring dissolution of calcium hydroxide and compensating for the leached calcium ions with another ion like lithium.

  5. Cementitious Barriers Partnership FY2013 End-Year Report

    SciTech Connect

    Flach, G. P.; Langton, C. A.; Burns, H. H.; Smith, F. G.; Kosson, D. S.; Brown, K. G.; Samson, E.; Meeussen, J. C.L.; van der Sloot, H. A.; Garboczi, E. J.

    2013-11-01

    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.

  6. Waste Separation Press (WSP): a mechanical pretreatment option for organic waste from source separation.

    PubMed

    Jank, Anna; Müller, Wolfgang; Schneider, Irene; Gerke, Frederic; Bockreis, Anke

    2015-05-01

    An efficient biological treatment of source separated organic waste from household kitchens and gardens (biowaste) requires an adequate upfront mechanical preparation which possibly includes a hand sorting for the separation of contaminants. In this work untreated biowaste from households and gardens and the screen overflow >60mm of the same waste were mechanically treated by a Waste Separation Press (WSP). The WSP separates the waste into a wet fraction for biological treatment and a fraction of dry contaminants for incineration. The results show that it is possible to replace a hand sorting of contaminants, the milling and a screening of organic waste before the biological treatment by using the WSP. A special focus was put on the contaminants separation. The separation of plastic film from the untreated biowaste was 67% and the separation rate of glass was about 92%. About 90% of the organics were transferred to the fraction for further biological treatment. When treating the screen overflow >60mm with the WSP 86% of the plastic film and 88% of the glass were transferred to the contaminants fraction. 32% of the organic was transferred to the contaminants fraction and thereby lost for a further biological treatment. Additionally it was calculated that national standards for glass contaminants in compost can be met when using the WSP to mechanically treat the total biowaste. The loss of biogas by transferring biodegradable organics to the contaminants fraction was about 11% when preparing the untreated biowaste with the WSP. PMID:25761398

  7. Options and costs for offsite disposal of oil and gas exploration and production wastes.

    SciTech Connect

    Puder, M. G.; Veil, J. A.; Environmental Science Division

    2007-01-01

    In the United States, most of the exploration and production (E&P) wastes generated at onshore oil and gas wells are disposed of or otherwise managed at the well site. Certain types of wastes are not suitable for onsite management, and some well locations in sensitive environments cannot be used for onsite management. In these situations, operators must transport the wastes offsite for disposal. In 1997, Argonne National Laboratory (Argonne) prepared a report that identified offsite commercial disposal facilities in the United States. This information has since become outdated. Over the past year, Argonne has updated the study through contacts with state oil and gas agencies and commercial disposal companies. The new report, including an extensive database for more than 200 disposal facilities, provides an excellent reference for information about commercial disposal operations. This paper describes Argonne's report. The national study provides summaries of the types of offsite commercial disposal facilities found in each state. Data are presented by waste type and by disposal method. The categories of E&P wastes in the database include: contaminated soils, naturally occurring radioactive material (NORM), oil-based muds and cuttings, produced water, tank bottoms, and water-based muds and cuttings. The different waste management or disposal methods in the database involve: bioremediation, burial, salt cavern, discharge, evaporation, injection, land application, recycling, thermal treatment, and treatment. The database includes disposal costs for each facility. In the United States, most of the 18 billion barrels (bbl) of produced water, 149 million bbl of drilling wastes, and 21 million bbl of associated wastes generated at onshore oil and gas wells are disposed of or otherwise managed at the well site. However, under certain conditions, operators will seek offsite management options for these E&P wastes. Commercial disposal facilities are offsite businesses that

  8. Development of a Performance and Processing Property Acceptance Region for Cementitious Low-Level Waste Forms at Savannah River Site - 13174

    SciTech Connect

    Staub, Aaron V.; Reigel, Marissa M.

    2013-07-01

    The Saltstone Production and Disposal Facilities (SPF and SDF) at the Savannah River Site (SRS) have been treating decontaminated salt solution, a low-level aqueous waste stream (LLW) since facility commissioning in 1990. In 2012, the Saltstone Facilities implemented a new Performance Assessment (PA) that incorporates an alternate design for the disposal facility to ensure that the performance objectives of DOE Order 435.1 and the National Defense Authorization Act (NDAA) of Fiscal Year 2005 Section 3116 are met. The PA performs long term modeling of the waste form, disposal facility, and disposal site hydrogeology to determine the transport history of radionuclides disposed in the LLW. Saltstone has been successfully used to dispose of LLW in a grout waste form for 15 years. Numerous waste form property assumptions directly impact the fate and transport modeling performed in the PA. The extent of process variability and consequence on performance properties are critical to meeting the assumptions of the PA. The SPF has ensured performance property acceptability by way of implementing control strategies that ensure the process operates within the analyzed limits of variability, but efforts continue to improve the understanding of facility performance in relation to the PA analysis. A similar understanding of the impact of variability on processing parameters is important from the standpoint of the operability of the production facility. The fresh grout slurry properties (particularly slurry rheology and the rate of hydration and structure formation) of the waste form directly impact the pressure and flow rates that can be reliably processed. It is thus equally important to quantify the impact of variability on processing parameters to ensure that the design basis assumptions for the production facility are maintained. Savannah River Remediation (SRR) has been pursuing a process that will ultimately establish a property acceptance region (PAR) to incorporate

  9. Life-cycle assessment of selected management options for air pollution control residues from waste incineration.

    PubMed

    Fruergaard, Thilde; Hyks, Jiri; Astrup, Thomas

    2010-09-15

    Based on available technology and emission data seven selected management options for air-pollution-control (APC) residues from waste incineration were evaluated by life-cycle assessment (LCA) using the EASEWASTE model. Scenarios were evaluated with respect to both non-toxicity impact categories (e.g. global warming) and toxicity related impact categories (e.g. ecotoxicity and human toxicity). The assessment addressed treatment and final placement of 1 tonne of APC residue in seven scenarios: 1) direct landfilling without treatment (baseline), 2) backfilling in salt mines, 3) neutralization of waste acid, 4) filler material in asphalt, 5) Ferrox stabilization, 6) vitrification, and 7) melting with automobile shredder residues (ASR). The management scenarios were selected as examples of the wide range of different technologies available worldwide while at the same time using realistic technology data. Results from the LCA were discussed with respect to importance of: energy consumption/substitution, material substitution, leaching, air emissions, time horizon aspects for the assessment, and transportation distances. The LCA modeling showed that thermal processes were associated with the highest loads in the non-toxicity categories (energy consumption), while differences between the remaining alternatives were small and generally considered insignificant. In the toxicity categories, all treatment/utilization options were significantly better than direct landfilling without treatment (lower leaching), although the thermal processes had somewhat higher impacts than the others options (air emissions). Transportation distances did not affect the overall ranking of the management alternatives. PMID:20599249

  10. Achieving Resource Conservation in Electronic Waste Management: A Review of Options Available to Developing Countries

    NASA Astrophysics Data System (ADS)

    Chidi Nnorom, Innocent; Osibanjo, Oladele; Onyedikachi Nnorom, Stanley

    Large quantities of waste electronic devices (e-waste) at their end-of-life, generated internally or imported illegally from developed countries, are currently being managed in the developing countries, through low-end means such as crude backyard recycling and disposal at unlined landfills or open dumps. The extension of the lifespan of electronic devices through reuse options such as repair, reconditioning and remanufacturing should be a priority in the management of electronic waste in developing countries considering the near absence of state-of-the-art recycling facilities in these countries. Life extension through product and component reuse is especially critical to electronic products because in recent years, electronics have increased in technological complexity, with new product innovations and ever shortening product life expectancy. For many products, environmentalists assume that reuse is environmentally beneficial because it replaces the manufacturing and purchase of new goods. However, on the contrary, manufacturers may oppose this type of reuse for the same reason. There is an urgent need to control the trans-boundary movement of electronic scrap especially to countries without established recycling facilities. Importations of secondhand electronics make such devices available to those who cannot afford new products. However, an international method of testing and certification is needed to ensure that exported secondhand devices are functional. Establishment of formal recycling facilities for e-waste in the developing countries will ensure resource reutilization with both economical and ecological gains. This study reviews options available in working towards eco-efficient management of e-waste in developing countries in the light of the present low-end management practices.

  11. A comparison of costs associated with utility management options for dry active waste

    SciTech Connect

    Hornibrook, C.

    1995-12-31

    The economics of low level waste management is receiving more attention today than ever before. This is due to four factors: (1) the increases in the cost of processing of these wastes; (2) increases in the cost of disposal; (3) the addition of storage costs for those without access to disposal; and (4) the increasing competitive nature of the electric generation industry. These pressures are forcing the industry to update it`s evaluation of the mix of processing that will afford it the best long term economics and minimize it`s risks for unforeseen costs. Whether disposal is available or not, all utilities face the same challenge of minimizing the costs associated with the management of these wastes. There are a number of variables that will impact how a utility manages their wastes but the problem is the uncertainty of what will actually happen, i.e., will disposal be available, when and at what cost. Using the EPRI-developed WASTECOST: DAW code, this paper explores a variety of LLW management options available to utilities. Along with providing the costs and benefits, other technical considerations which play an important part in the management of these wastes are also addressed.

  12. A Study on Optimized Management Options for the Wolsong Low- and Intermediate - Level Waste Disposal Center in Korea - 13479

    SciTech Connect

    Park, JooWan; Kim, DongSun; Choi, DongEun

    2013-07-01

    The safe and effective management of radioactive waste is a national task required for sustainable generation of nuclear power and for energy self-reliance in Korea. Currently, for permanent disposal of low- and intermediate-level waste (LILW), the Wolsong LILW Disposal Center (WLDC) is under construction. It will accommodate a total of 800,000 drums at the final stage after stepwise expansion. As an implementing strategy for cost-effective development of the WLDC, various disposal options suitable for waste classification schemes would be considered. It is also needed an optimized management of the WLDC by taking a countermeasure of volume reduction treatment. In this study, various management options to be applied to each waste class are analyzed in terms of its inventory and disposal cost. For the volume reduction and stabilization of waste, the vitrification and plasma melting methods are considered for combustible and incombustible waste, respectively. (authors)

  13. REVIEW OF MECHANISTIC UNDERSTANDING AND MODELING AND UNCERTAINTY ANALYSIS METHODS FOR PREDICTING CEMENTITIOUS BARRIER PERFORMANCE

    SciTech Connect

    Langton, C.; Kosson, D.

    2009-11-30

    Cementitious barriers for nuclear applications are one of the primary controls for preventing or limiting radionuclide release into the environment. At the present time, performance and risk assessments do not fully incorporate the effectiveness of engineered barriers because the processes that influence performance are coupled and complicated. Better understanding the behavior of cementitious barriers is necessary to evaluate and improve the design of materials and structures used for radioactive waste containment, life extension of current nuclear facilities, and design of future nuclear facilities, including those needed for nuclear fuel storage and processing, nuclear power production and waste management. The focus of the Cementitious Barriers Partnership (CBP) literature review is to document the current level of knowledge with respect to: (1) mechanisms and processes that directly influence the performance of cementitious materials (2) methodologies for modeling the performance of these mechanisms and processes and (3) approaches to addressing and quantifying uncertainties associated with performance predictions. This will serve as an important reference document for the professional community responsible for the design and performance assessment of cementitious materials in nuclear applications. This review also provides a multi-disciplinary foundation for identification, research, development and demonstration of improvements in conceptual understanding, measurements and performance modeling that would be lead to significant reductions in the uncertainties and improved confidence in the estimating the long-term performance of cementitious materials in nuclear applications. This report identifies: (1) technology gaps that may be filled by the CBP project and also (2) information and computational methods that are in currently being applied in related fields but have not yet been incorporated into performance assessments of cementitious barriers. The various

  14. OVERVIEW OF THE U.S. DEPARTMENT OF ENERGY AND NUCLEAR REGULATORY COMMISSION PERFORMANCE ASSESSMENT APPROACHES: CEMENTITIOUS BARRIERS PARTNERSHIP

    SciTech Connect

    Langton, C.; Burns, H.

    2009-05-29

    Engineered barriers including cementitious barriers are used at sites disposing or contaminated with low-level radioactive waste to enhance performance of the natural environment with respect to controlling the potential spread of contaminants. Drivers for using cementitious barriers include: high radionuclide inventory, radionuclide characteristics (e.g., long half-live, high mobility due to chemical form/speciation, waste matrix properties, shallow water table, and humid climate that provides water for leaching the waste). This document comprises the first in a series of reports being prepared for the Cementitious Barriers Partnership. The document is divided into two parts which provide a summary of: (1) existing experience in the assessment of performance of cementitious materials used for radioactive waste management and disposal and (2) sensitivity and uncertainty analysis approaches that have been applied for assessments. Each chapter is organized into five parts: Introduction, Regulatory Considerations, Specific Examples, Summary of Modeling Approaches and Conclusions and Needs. The objective of the report is to provide perspective on the state of the practice for conducting assessments for facilities involving cementitious barriers and to identify opportunities for improvements to the existing approaches. Examples are provided in two contexts: (1) performance assessments conducted for waste disposal facilities and (2) performance assessment-like analyses (e.g., risk assessments) conducted under other regulatory regimes. The introductory sections of each section provide a perspective on the purpose of performance assessments and different roles of cementitious materials for radioactive waste management. Significant experience with assessments of cementitious materials associated with radioactive waste disposal concepts exists in the US Department of Energy Complex and the commercial nuclear sector. Recently, the desire to close legacy facilities has created

  15. Thermodynamic modeling of the sorption of radioelements onto cementitious materials

    SciTech Connect

    Heath, T.G.; Ilett, D.J.; Tweed, C.J.

    1996-08-01

    A model has been developed for the sorption of radioelements onto cementitious materials based on the diffuse-layer modeling approach. The model assumes that silicon sites (>SiOH) and calcium sites (>CaOH) dominate the surface chemistry and the sorption of radioelements onto the cementitious materials. Both types of site may undergo surface protonation and deprotonation reactions. Cement-based systems vary greatly in their chemistry depending on their calcium-to-silicon molar ratio, and the corresponding variation in the surface chemistry has been incorporated by allowing sorption of calcium ions onto silicon sites. This process results in a change from a silica-type surface, at very low calcium-silicon ratios, to a calcium hydroxide-type surface for high-calcium cement-based materials. The predicted variation in the surface chemistry is consistent with literature data on measured zeta potentials of cements. The model has been applied successfully to describe the sorption of simple caesium and iodide ions at varying calcium-silicon ratios. In a Nirex repository for low and intermediate level wastes, a high-calcium cementitious backfill would be specified. This model has allowed a consistent interpretation of experimental data for sorption of key radioelements, including uranium and plutonium, onto the backfill, under saline and non-saline conditions.

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

    SciTech Connect

    Smith, F.; Flach, G.

    2015-03-30

    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 as 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.

  17. A new and superior ultrafine cementitious grout

    SciTech Connect

    Ahrens, E.H.

    1997-04-01

    Sealing fractures in nuclear waste repositories concerns all programs investigating deep burial as a means of disposal. Because the most likely mechanism for contaminant migration is by dissolution and movement through groundwater, sealing programs are seeking low-viscosity sealants that are chemically, mineralogically, and physically compatible with the host rock. This paper presents the results of collaborative work directed by Sandia National Laboratories (SNL) and supported by Whiteshell Laboratories, operated by Atomic Energy of Canada, Ltd. The work was undertaken in support of the Waste Isolation Pilot Plant (WIPP), an underground nuclear waste repository located in a salt formation east of Carlsbad, NM. This effort addresses the technology associated with long-term isolation of nuclear waste in a natural salt medium. The work presented is part of the WIPP plugging and sealing program, specifically the development and optimization of an ultrafine cementitious grout that can be injected to lower excessive, strain-induced hydraulic conductivity in the fractured rock termed the Disturbed Rock Zone (DRZ) surrounding underground excavations. Innovative equipment and procedures employed in the laboratory produced a usable cement-based grout; 90% of the particles were smaller than 8 microns and the average particle size was 4 microns. The process involved simultaneous wet pulverization and mixing. The grout was used for a successful in situ test underground at the WIPP. Injection of grout sealed microfractures as small as 6 microns (and in one rare instance, 3 microns) and lowered the gas transmissivity of the DRZ by up to three orders of magnitude. Following the WIPP test, additional work produced an improved version of the grout containing particles 90% smaller than 5 microns and averaging 2 microns. This grout will be produced in dry form, ready for the mixer.

  18. The influence of natural organic matter on radionuclide mobility under conditions relevant to cementitious disposal of radioactive wastes: A review of direct evidence

    NASA Astrophysics Data System (ADS)

    Stockdale, Anthony; Bryan, Nick D.

    2013-06-01

    A concept for the disposal of intermediate level radioactive wastes involves emplacement within a geological disposal facility, followed by backfilling of the facility with cement. When the closed facility is re-saturated with groundwater, this will create a high pH environment due to dissolution of the cement minerals. Dissolved organic matter (DOM; defined here as naturally occurring organic acids and humin) will be present in the groundwater at a concentration that reflects the host rock environment and the recharge source and pathway. Interactions between DOM and radionuclides may enhance transport away from the facility and are an important consideration in safety performance assessments. This review specifically focuses on studies of DOM-radionuclide interactions at the high pH range that is expected during a repository lifetime. Whilst the vast majority of available data cover binary (DOM-radionuclide) and batch ternary systems (mineral-radionuclide-DOM), this review also covers other potentially important areas, such as reversibility kinetics and redox processes that can be mediated by DOM.

  19. Systematic evaluation of options to avoid generation of noncertifiable transuranic (TRU) waste at Los Alamos National Laboratory

    SciTech Connect

    Boak, J.M.; Kosiewicz, S.T.; Triay, I.; Gruetzmacher, K.; Montoya, A.

    1998-03-01

    At present, >35% of the volume of newly generated transuranic (TRU) waste at Los Alamos National Laboratory is not certifiable for transport to the Waste Isolation Pilot Plant (WIPP). Noncertifiable waste would constitute 900--1,000 m{sup 3} of the 2,600 m{sup 3} of waste projected during the period of the Environmental Management (EM) Accelerated Cleanup: Focus on 2006 plan (DOE, 1997). Volume expansion of this waste to meet thermal limits would increase the shipped volume to {approximately}5,400 m{sup 3}. This paper presents the results of efforts to define which TRU waste streams are noncertifiable at Los Alamos, and to prioritize site-specific options to reduce the volume of certifiable waste over the period of the EM Accelerated Cleanup Plan. A team of Los Alamos TRU waste generators and waste managers reviewed historic generation rates and thermal loads and current practices to estimate the projected volume and thermal load of TRU waste streams for Fiscal Years 1999--2006. These data defined four major problem TRU waste streams. Estimates were also made of the volume expansion that would be required to meet the permissible wattages for all waste. The four waste streams defined were: (1) {sup 238}Pu-contaminated combustible waste from production of Radioactive Thermoelectric Generators (RTGs) with {sup 238}Pu activity which exceeds allowable shipping limits by 10--100X. (2) {sup 241}Am-contaminated cement waste from plutonium recovery processes (nitric and hydrochloric acid recovery) are estimated to exceed thermal limits by {approximately}3X. (3) {sup 239}Pu-contaminated combustible waste, mainly organic waste materials contaminated with {sup 239}Pu and {sup 241}Am, is estimated to exceed thermal load requirements by a factor of {approximately}2X. (4) Oversized metal waste objects, (especially gloveboxes), cannot be shipped as is to WIPP because they will not fit in a standard waste box or drum.

  20. Assessment of the long-term stability of cementitious barriers of radioactive waste repositories by using digital-image-based microstructure generation and reactive transport modelling

    SciTech Connect

    Galindez, Juan Manuel; Molinero, Jorge

    2010-08-15

    Cement-based grout plays a significant role in the design and performance of nuclear waste repositories: used correctly, it can enhance their safety. However, the high water-to-binder ratios, which are required to meet the desired workability and injection ability at early age, lead to high porosity that may affect the durability of this material and undermine its long-term geochemical performance. In this paper, a new methodology is presented in order to help the process of mix design which best meets the compromise between these two conflicting requirements. It involves the combined use of the computer programs CEMHYD3D for the generation of digital-image-based microstructures and CrunchFlow, for the reactive transport calculations affecting the materials so simulated. This approach is exemplified with two grout types, namely, the so-called Standard mix 5/5, used in the upper parts of the structure, and the 'low-pH' P308B, to be injected at higher depths. The results of the digital reconstruction of the mineralogical composition of the hardened paste are entirely logical, as the microstructures display high degrees of hydration, large porosities and low or nil contents of aluminium compounds. Diffusion of solutes in the pore solution was considered to be the dominant transport process. A single scenario was studied for both mix designs and their performances were compared. The reactive transport model adequately reproduces the process of decalcification of the C-S-H and the precipitation of calcite, which is corroborated by empirical observations. It was found that the evolution of the deterioration process is sensitive to the chemical composition of groundwater, its effects being more severe when grout is set under continuous exposure to poorly mineralized groundwater. Results obtained appear to indicate that a correct conceptualization of the problem was accomplished and support the assumption that, in absence of more reliable empirical data, it might

  1. A direct steam heat option for hydrothermal treatment of municipal solid waste

    SciTech Connect

    Thorsness, C.B.

    1995-04-12

    A conceptual process for producing a gasifiable slurry from raw municipal solid waste (MSW) using direct steam heating is outlined. The process is based on the hydrothermal decomposition of the organic matter in the MSW, which requires the MSW to be heated to 300-350{degrees}C in the presence of water. A process model is developed and it is shown, based on preliminary estimates of the hydrothermal reaction stoichiometry, that a process using multiple pressure vessels, which allows recovery of waste heat, results in a process capable of producing a product slurry having a 40 wt % solids content with no waste water emissions. Results for a variety of process options and process parameters are presented. It is shown that the addition of auxiliary feedstock to the gasifier, along with the MSW derived slurry, results in more efficient gasification. It is estimated that 2.6 kmol/s of hydrogen can be produced from 30 kg/s (2600 tonne/day) of MSW and 16 kg/s of heavy oil. Without the additional feedstock, heavy oil in this case, only 0.49 kmol/s of hydrogen would be produced.

  2. Validity and reliability of estimated modulus of elasticity of cementitious materials

    NASA Astrophysics Data System (ADS)

    Kockal, N. U.

    2015-12-01

    Modulus of elasticity is a vital property in cementitious material (CM) design and analysis. A better understanding of the relationship between density, strength and stiffness is needed to construct proper structures especially with reinforced cementitious materials. For this purpose, modulus of elasticity of CMs with different waste aggregates was analyzed and the reliability of estimated values of various equations proposed by standards and sources in literature, suggested in this investigation and derived by a software chosen was discussed. The results demonstrated that as compared to experimental results, the model developed by software was the most accurate as the percentages of error in prediction were in a good agreement.

  3. Using Department of Energy (DOE) Order 435.1 To Find a Cost Effective Waste Management Option. - 12241

    SciTech Connect

    LaBarge, Matt; Frost, Matt

    2012-07-01

    The Depleted Uranium Hexafluoride Project in Portsmouth Ohio was faced with an interesting dilemma. During hot functional testing in August 2010, an upset condition caused gaseous depleted uranium hexafluoride (UF{sub 6}) to come in contact with the hydrofluoric acid (HF) vapor stream. Although the resulting uranium contamination found in the condensed aqueous hydrofluoric acid was very low, it exceeded the Department of Energy (DOE) authorized release limit. After evaluating several commercial options for treatment and disposal using the guidelines found in DOE Order 435.1, Waste Control Specialists LLC was selected for the treatment of the waste, with EnergySolutions' Clive facility selected for disposal of the treated residues. The waste was safely transported from Piketon, Ohio to Andrews, Texas, where it was treated to meet the land Disposal Restrictions (LDR), and was disposed in EnergySolutions operational mixed waste cell. The entire effort was interesting for several reasons. The waste was generated during the last year of the first Depleted Uranium Hexafluoride contractor. The waste became additional scope for the new contractor, adding time delays and introducing new personnel into the project. The effort was also unique because it demonstrated the process mandated by DOE Order 435.1 to evaluate all options, including commercial options, could reveal solutions to waste management problems that are currently available and more cost effective, but not well know within the DOE complex. (authors)

  4. An analytic network process model for municipal solid waste disposal options

    SciTech Connect

    Khan, Sheeba Faisal, Mohd Nishat

    2008-07-01

    The aim of this paper is to present an evaluation method that can aid decision makers in a local civic body to prioritize and select appropriate municipal solid waste disposal methods. We introduce a hierarchical network (hiernet) decision structure and apply the analytic network process (ANP) super-matrix approach to measure the relative desirability of disposal alternatives using value judgments as the input of the various stakeholders. ANP is a flexible analytical program that enables decision makers to find the best possible solution to complex problems by breaking down a problem into a systematic network of inter-relationships among the various levels and attributes. This method therefore may not only aid in selecting the best alternative but also helps decision makers to understand why an alternative is preferred over the other options.

  5. Modeling of NOx Destruction Options for INEEL Sodium-Bearing Waste Vitrification

    SciTech Connect

    Wood, Richard Arthur

    2001-09-01

    Off-gas NOx concentrations in the range of 1-5 mol% are expected as a result of the proposed vitrification of sodium-bearing waste at the Idaho National Engineering and Environmental Laboratory. An existing kinetic model for staged combustion (originally developed for NOx abatement from the calcination process) was updated for application to vitrification offgas. In addition, two new kinetic models were developed to assess the feasibility of using selective non-catalytic reduction (SNCR) or high-temperature alone for NOx abatement. Each of the models was developed using the Chemkin code. Results indicate that SNCR is a viable option, reducing NOx levels to below 1000 ppmv. In addition, SNCR may be capable of simultaneously reducing CO emissions to below 100 ppmv. Results for using high-temperature alone were not as promising, indicating that a minimum NOx concentration of 3950 ppmv is achievable at 3344°F.

  6. Integrated vermi-pisciculture--an alternative option for recycling of solid municipal waste in rural India.

    PubMed

    Ghosh, Chirashree

    2004-05-01

    Vermicomposts as a biofertilizer can be a great option for pond manuring as they never cause any long term harm to the soil like chemical fertilizer. In this study vegetable and horticulture waste was used as an important media for vermiculture. Three separate cemented tanks (6 m(3) each) were used in the system as control tank, vermicompost fertilized tank and inorganic fertilizer manured tank. Monoculture of fish was carried out with cat fish, Clarias batrachus. The produced earthworms were used as fish feed. Regular monitoring of water parameter was conducted in three different ponds. Specifically, the algal biomass variation was quite helpful in analyzing the behavior of the ponds. NPK value of soil samples were analyzed intermittently to know the eutrophication level. Despite the hot summer temperature in northern part of India, which is not ideal for fish growth, we have recorded an encouraging growth performance in organic manured pond along with inorganic fertilizer treated and control pond. Among eutrophicated pond, the fish biomass from vermicompost fed pond showed an increasing trend compared to inorganic fertilizer treated pond. Water retention capacity of vermicompost pond soil was better in comparison to other ponds. Result shows that the low cost model by integrating two production system vermiculture and pisciculture could be a commercially and environmentally viable option. PMID:14987723

  7. Degradation Of Cementitious Materials Associated With Saltstone Disposal Units

    SciTech Connect

    Flach, G. P; Smith, F. G. III

    2013-03-19

    The Saltstone facilities at the DOE Savannah River Site (SRS) stabilize and dispose of low-level radioactive salt solution originating from liquid waste storage tanks at the site. The Saltstone Production Facility (SPF) receives treated salt solution and mixes the aqueous waste with dry cement, blast furnace slag, and fly ash to form a grout slurry which is mechanically pumped into concrete disposal cells that compose the Saltstone Disposal Facility (SDF). The solidified grout is termed “saltstone”. Cementitious materials play a prominent role in the design and long-term performance of the SDF. The saltstone grout exhibits low permeability and diffusivity, and thus represents a physical barrier to waste release. The waste form is also reducing, which creates a chemical barrier to waste release for certain key radionuclides, notably Tc-99. Similarly, the concrete shell of an SDF disposal unit (SDU) represents an additional physical and chemical barrier to radionuclide release to the environment. Together the waste form and the SDU compose a robust containment structure at the time of facility closure. However, the physical and chemical state of cementitious materials will evolve over time through a variety of phenomena, leading to degraded barrier performance over Performance Assessment (PA) timescales of thousands to tens of thousands of years. Previous studies of cementitious material degradation in the context of low-level waste disposal have identified sulfate attack, carbonation influenced steel corrosion, and decalcification (primary constituent leaching) as the primary chemical degradation phenomena of most relevance to SRS exposure conditions. In this study, degradation time scales for each of these three degradation phenomena are estimated for saltstone and concrete associated with each SDU type under conservative, nominal, and best estimate assumptions. The nominal value (NV) is an intermediate result that is more probable than the conservative

  8. Clean option: An alternative strategy for Hanford Tank Waste Remediation. Volume 2, Detailed description of first example flowsheet

    SciTech Connect

    Swanson, J.L.

    1993-09-01

    Disposal of high-level tank wastes at the Hanford Site is currently envisioned to divide the waste between two principal waste forms: glass for the high-level waste (HLW) and grout for the low-level waste (LLW). The draft flow diagram shown in Figure 1.1 was developed as part of the current planning process for the Tank Waste Remediation System (TWRS), which is evaluating options for tank cleanup. The TWRS has been established by the US Department of Energy (DOE) to safely manage the Hanford tank wastes. It includes tank safety and waste disposal issues, as well as the waste pretreatment and waste minimization issues that are involved in the ``clean option`` discussed in this report. This report describes the results of a study led by Pacific Northwest Laboratory to determine if a more aggressive separations scheme could be devised which could mitigate concerns over the quantity of the HLW and the toxicity of the LLW produced by the reference system. This aggressive scheme, which would meet NRC Class A restrictions (10 CFR 61), would fit within the overall concept depicted in Figure 1.1; it would perform additional and/or modified operations in the areas identified as interim storage, pretreatment, and LLW concentration. Additional benefits of this scheme might result from using HLW and LLW disposal forms other than glass and grout, but such departures from the reference case are not included at this time. The evaluation of this aggressive separations scheme addressed institutional issues such as: radioactivity remaining in the Hanford Site LLW grout, volume of HLW glass that must be shipped offsite, and disposition of appropriate waste constituents to nonwaste forms.

  9. GRAFEC: A New Spanish Program to Investigate Waste Management Options for Radioactive Graphite - 12399

    SciTech Connect

    Marquez, Eva; Pina, Gabriel; Rodriguez, Marina; Fachinger, Johannes; Grosse, Karl-Heinz; Leganes Nieto, Jose Luis; Quiros Gracian, Maria

    2012-07-01

    Spain has to manage about 3700 tons of irradiated graphite from the reactor Vandellos I as radioactive waste. 2700 tons are the stack of the reactor and are still in the reactor core waiting for retrieval. The rest of the quantities, 1000 tons, are the graphite sleeves which have been already retrieved from the reactor. During operation the graphite sleeves were stored in a silo and during the dismantling stage a retrieval process was carried out separating the wires from the graphite, which were crushed and introduced into 220 cubic containers of 6 m{sup 3} each and placed in interim storage. The graphite is an intermediate level radioactive waste but it contains long lived radionuclides like {sup 14}C which disqualifies disposal at the low level waste repository of El Cabril. Therefore, a new project has been started in order to investigate two new options for the management of this waste type. The first one is based on a selective decontamination of {sup 14}C by thermal methods. This method is based on results obtained at the Research Centre Juelich (FZJ) in the Frame of the EC programs 'Raphael' and 'Carbowaste'. The process developed at FZJ is based on a preferential oxidation of {sup 14}C in comparison to the bulk {sup 12}C. Explanations for this effect are the inhomogeneous distribution and a weaker bounding of {sup 14}C which is not incorporated in the graphite lattice. However these investigations have only been performed with graphite from the high temperature reactor Arbeitsgemeinschaft Versuchsreaktor Juelich AVR which has been operated in a non-oxidising condition or research reactor graphite operated at room temperature. The reactor Vandellos I has been operated with CO{sub 2} as coolant and significant amounts of graphite have been already oxidised. The aim of the project is to validate whether a {sup 14}C decontamination can also been achieved with graphite from Vandellos I. A second possibility under investigation is the encapsulation of the

  10. Air pollution control residues from waste incineration: Current UK situation and assessment of alternative technologies

    SciTech Connect

    Amutha Rani, D.; Boccaccini, A.R.; Deegan, D.; Cheeseman, C.R.

    2008-11-15

    Current disposal options for APC residues in the UK and alternative treatment technologies developed world-wide have been reviewed. APC residues are currently landfilled in the UK where they undergo in situ solidification, although the future acceptability of this option is uncertain because the EU waste acceptance criteria (WAC) introduce strict limits on leaching that are difficult to achieve. Other APC residue treatment processes have been developed which are reported to reduce leaching to below relevant regulatory limits. The Ferrox process, the VKI process, the WES-PHix process, stabilisation/solidification using cementitious binders and a range of thermal treatment processes are reviewed. Thermal treatment technologies convert APC residues combined with other wastes into inert glass or glass-ceramics that encapsulate heavy metals. The waste management industry will inevitably use the cheapest available option for treating APC residues and strict interpretation and enforcement of waste legislation is required if new, potentially more sustainable technologies are to become commercially viable.

  11. Evaluation of food waste disposal options by LCC analysis from the perspective of global warming: Jungnang case, South Korea

    SciTech Connect

    Kim, Mi-Hyung; Song, Yul-Eum; Song, Han-Byul; Kim, Jung-Wk; Hwang, Sun-Jin

    2011-09-15

    Highlights: > Various food waste disposal options were evaluated from the perspective of global warming. > Costs of the options were compared by the methodology of life cycle assessment and life cycle cost analysis. > Carbon price and valuable by-products were used for analyzing environmental credits. > The benefit-cost ratio of wet feeding scenario was the highest. - Abstract: The costs associated with eight food waste disposal options, dry feeding, wet feeding, composting, anaerobic digestion, co-digestion with sewage sludge, food waste disposer, incineration, and landfilling, were evaluated in the perspective of global warming and energy and/or resource recovery. An expanded system boundary was employed to compare by-products. Life cycle cost was analyzed through the entire disposal process, which included discharge, separate collection, transportation, treatment, and final disposal stages, all of which were included in the system boundary. Costs and benefits were estimated by an avoided impact. Environmental benefits of each system per 1 tonne of food waste management were estimated using carbon prices resulting from CO{sub 2} reduction by avoided impact, as well as the prices of by-products such as animal feed, compost, and electricity. We found that the cost of landfilling was the lowest, followed by co-digestion. The benefits of wet feeding systems were the highest and landfilling the lowest.

  12. Advanced Fuel Cycles for Fusion Reactors: Passive Safety and Zero-Waste Options

    NASA Astrophysics Data System (ADS)

    Zucchetti, Massimo; Sugiyama, Linda E.

    2006-05-01

    Nuclear fusion is seen as a much ''cleaner'' energy source than fission. Most of the studies and experiments on nuclear fusion are currently devoted to the Deuterium-Tritium (DT) fuel cycle, since it is the easiest way to reach ignition. The recent stress on safety by the world's community has stimulated the research on other fuel cycles than the DT one, based on 'advanced' reactions, such as the Deuterium-Helium-3 (DHe) one. These reactions pose problems, such as the availability of 3He and the attainment of the higher plasma parameters that are required for burning. However, they have many advantages, like for instance the very low neutron activation, while it is unnecessary to breed and fuel tritium. The extrapolation of Ignitor technologies towards a larger and more powerful experiment using advanced fuel cycles (Candor) has been studied. Results show that Candor does reach the passive safety and zero-waste option. A fusion power reactor based on the DHe cycle could be the ultimate response to the environmental requirements for future nuclear power plants.

  13. A decision methodology for the evaluation of mixed low-level radioactive waste management options for DOE sites

    SciTech Connect

    Bassi, J.; Abashian, M.S.; Chakraborti, S.; Devarakonda, M.; Djordjevic, S.M.

    1993-03-01

    Currently, many DOE sites are developing site-specific solutions to manage their mixed low-level wastes. These site-specific MLLW programs often result in duplication of efforts between the different sites, and consequently, inefficient use of DOE system resources. A nationally integrated program for MLLW eliminates unnecessary duplication of effort, but requires a comprehensive analysis of waste management options to ensure that all site issues are addressed. A methodology for comprehensive analysis of the complete DOE MLLW system is being developed by DOE-HQ to establish an integrated and standardized solution for managing MLLW. To be effective, the comprehensive systems analysis must consider all aspects of MLLW management from cradle-to-grave (i.e. from MLLW generation to disposal). The results of the analysis will include recommendations for alternative management options for the complete DOE MLLW system based on various components such as effectiveness, cost, health and safety risks, and the probability of regulatory acceptance for an option. Because of the diverse nature of these various components and the associated difficulties in comparing between them, a decision methodology is being developed that will integrate the above components into a single evaluation scheme for performing relative comparisons between different MLLW management options. The remainder of this paper provides an overview of the roles and responsibilities of the various participants of the DOE MLLW Program, and discusses in detail the components involved in the development of the decision methodology for a comprehensive systems analysis.

  14. Effect of extraction solutions on carbonation of cementitious materials in aqueous solutions.

    PubMed

    Jo, Hwanju; Jo, Ho Young; Jang, Young-Nam

    2012-06-01

    Carbonation efficiency was evaluated for three cementitious materials having different CaO-bearing minerals (lime, Portland cement and waste concrete) using various extraction reagents (HCl, CH3COOH, NH4Cl and deionized water). The cementitious materials were subjected to Ca extraction and carbonation tests under ambient pressure and temperature conditions. The Ca extraction efficiency generally decreased in the order lime, Portland cement and waste concrete, regardless of the extraction solution. Among the extraction solutions, NH4Cl was the most effective for Ca extraction and carbonation. The results of this study suggest that the types of extraction solution and CaO-bearing mineral of the materials are primary factors affecting carbonation efficiency. PMID:22856314

  15. VARIABILITY OF KD VALUES IN CEMENTITIOUS MATERIALS AND SEDIMENTS

    SciTech Connect

    Almond, P.; Kaplan, D.; Shine, E.

    2012-02-02

    Measured distribution coefficients (K{sub d} values) for environmental contaminants provide input data for performance assessments (PA) that evaluate physical and chemical phenomena for release of radionuclides from wasteforms, degradation of engineered components and subsequent transport of radionuclides through environmental media. Research efforts at SRNL to study the effects of formulation and curing variability on the physiochemical properties of the saltstone wasteform produced at the Saltstone Disposal Facility (SDF) are ongoing and provide information for the PA and Saltstone Operations. Furthermore, the range and distribution of plutonium K{sub d} values in soils is not known. Knowledge of these parameters is needed to provide guidance for stochastic modeling in the PA. Under the current SRS liquid waste processing system, supernate from F & H Tank Farm tanks is processed to remove actinides and fission products, resulting in a low-curie Decontaminated Salt Solution (DSS). At the Saltstone Production Facility (SPF), DSS is mixed with premix, comprised of blast furnace slag (BFS), Class F fly ash (FA), and portland cement (OPC) to form a grout mixture. The fresh grout is subsequently placed in SDF vaults where it cures through hydration reactions to produce saltstone, a hardened monolithic waste form. Variation in saltstone composition and cure conditions of grout can affect the saltstone's physiochemical properties. Variations in properties may originate from variables in DSS, premix, and water to premix ratio, grout mixing, placing, and curing conditions including time and temperature (Harbour et al. 2007; Harbour et al. 2009). There are no previous studies reported in the literature regarding the range and distribution of K{sub d} values in cementitious materials. Presently, the Savannah River Site (SRS) estimate ranges and distributions of K{sub d} values based on measurements of K{sub d} values made in sandy SRS sediments (Kaplan 2010). The actual

  16. Options for management of municipal solid waste in New York City: A preliminary comparison of health risks and policy implications

    PubMed Central

    Moy, Pearl; Krishnan, Nikhil; Ulloa, Priscilla; Cohen, Steven; Brandt-Rauf, Paul W.

    2008-01-01

    Landfill disposal and waste-to-energy (WTE) incineration remain the two principal options for managing municipal solid waste (MSW). One critical determinant of the acceptability of these options is the different health risks associated with each. In this analysis relying on published data and exposure modeling, we have performed health risk assessments for landfill disposal versus WTE treatment options for the management of New York City’s MSW. These are based on the realistic scenario of using a waste transfer station (WTS) in Brooklyn and then transporting the untreated MSW by truck to a landfill in Pennsylvania or using a WTE facility in Brooklyn and then transporting the resultant ash by truck to a landfill in Pennsylvania. The overall results indicate that the individual cancer risks for both options would be considered generally acceptable, although the risk from landfilling is approximately 5 times greater than from WTE treatment; the individual non-cancer health risks for both options would be considered generally unacceptable, although once again the risk from landfilling is approximately 5 times greater than from WTE treatment. If one considers only the population in Brooklyn that would be directly affected by the siting of either a WTS or a WTE facility in their immediate neighborhood, individual cancer and non-cancer health risks for both options would be considered generally acceptable, but risks for the former remain considerably higher than for the latter. These results should be considered preliminary due to several limitations of this study such as: consideration of risks only from inhalation exposures; assumption that only volume and not composition of the waste stream is altered by WTE treatment; reliance on data from the literature rather than actual measurements of the sites considered, assuming comparability of the sites. However, the results of studies such as this, in conjunction with ecological, socioeconomic and equity considerations

  17. ANALYSIS OF THE POTENTIAL EFFECTS OF TOXICS ON MUNICIPAL SOLID WASTE MANAGEMENT OPTIONS

    EPA Science Inventory

    Many alternative waste management practices and strategies are available to manage the large quantities of MSW generated every year. hese management alternatives include recycling, composting, waste-to-fuel/energy recovery, and landfilling. n choosing the best possible management...

  18. ANALYSIS OF THE POTENTIAL EFFECTS OF TOXICS ON MUNICIPAL SOLID WASTE MANGEMENT OPTIONS

    EPA Science Inventory

    Many alternative waste management practices and strategies are available to manage the large quantities of MSW generated every year. These management alternatives include recycling, composting, waste-to-fuel/energy recovery, and landfilling. In choosing the best possible manageme...

  19. A multi-criteria analysis of options for energy recovery from municipal solid waste in India and the UK.

    PubMed

    Yap, H Y; Nixon, J D

    2015-12-01

    Energy recovery from municipal solid waste plays a key role in sustainable waste management and energy security. However, there are numerous technologies that vary in suitability for different economic and social climates. This study sets out to develop and apply a multi-criteria decision making methodology that can be used to evaluate the trade-offs between the benefits, opportunities, costs and risks of alternative energy from waste technologies in both developed and developing countries. The technologies considered are mass burn incineration, refuse derived fuel incineration, gasification, anaerobic digestion and landfill gas recovery. By incorporating qualitative and quantitative assessments, a preference ranking of the alternative technologies is produced. The effect of variations in decision criteria weightings are analysed in a sensitivity analysis. The methodology is applied principally to compare and assess energy recovery from waste options in the UK and India. These two countries have been selected as they could both benefit from further development of their waste-to-energy strategies, but have different technical and socio-economic challenges to consider. It is concluded that gasification is the preferred technology for the UK, whereas anaerobic digestion is the preferred technology for India. We believe that the presented methodology will be of particular value for waste-to-energy decision-makers in both developed and developing countries. PMID:26275797

  20. Call It Trash, Garbage or Refuse: Four Case Studies Illustrate Community Waste Management Options.

    ERIC Educational Resources Information Center

    Kazzi, John W.

    1990-01-01

    Describes four successful community programs dealing with waste management issues, developed with assistance from Keep America Beautiful System: litter prevention (Beatrice, Nebraska); composting yard waste (Centralia, Illinois); recycling (Lake Jackson, Texas); and waste-to-energy incineration (Gastonia, North Carolina). Notes related education…

  1. Impact of the European Union vehicle waste directive on end-of-life options for polymer electrolyte fuel cells

    NASA Astrophysics Data System (ADS)

    Handley, C.; Brandon, N. P.; van der Vorst, R.

    Polymer electrolyte membrane fuel cells (PEMFCs) may well be powering millions of cars by 2020. At its end-of-life, each car will have a redundant PEMFC stack. The EU vehicle waste directive sets tough recycling and re-use requirements for the cars of the future. The criteria for assessing the end-of-life options are based on technical, economic and environmental feasibility. The optimum strategy will require stack dismantling and separation of the major components. Steel and aluminium parts can enter the general recycling stream, but the membrane electrode assembly and bipolar plates will require a specialised recycling process. One option is to shred the MEA, dissolve and recover the membrane, burn off the carbon, and recycle the platinum and ruthenium catalysts using solvent extraction. The heaviest part of the PEMFC stack is the bipolar plates. If carbon fibre based, the bipolar plates could enter a fluidised bed recovery process where the constituent materials are recovered for re-use. The EU vehicle waste directive sets high recycling targets based on weight, and thus it is strongly advisable for the relatively heavy bipolar plates to be recycled, even though energy recovery by incineration may be a cheaper and possible more environmentally benign option. The EU vehicle directive will put pressure on the end-of-life options for the PEMFC stack to be weighted towards recycling and re-use; it will have a significant impact on the design and end-of-life options for the PEMFC. The overall effect of this pressure on the end-of-life treatment of the PEMFC and the consequential contribution to environmental life cycle impacts is discussed. It is concluded that a range of external pressures influence the selection of a suitable end-of-life management strategy, and while opportunities for re-use of components are limited, all components of the PEMFC stack could in principle be recycled.

  2. Expediting the commercial disposal option: Low-level radioactive waste shipments from the Mound Plant

    SciTech Connect

    Rice, S.; Rothman, R.

    1995-12-31

    In April, Envirocare of Utah, Inc., successfully commenced operation of its mixed waste treatment operation. A mixed waste which was (a) radioactive, (b) listed as a hazardous waste under the Resource Conservation and Recovery Act (RCRA), and (c) prohibited from land disposal was treated using Envirocare`s full-scale Mixed Waste Treatment Facility. The treatment system involved application of chemical fixation/stabilization technologies to reduce the leachability of the waste to meet applicable concentration-based RCRA treatment standards. In 1988, Envirocare became the first licensed facility for the disposal of naturally occurring radioactive material. In 1990, Envirocare received a RCRA Part B permit for commercial mixed waste storage and disposal. In 1994, Envirocare was awarded a contract for the disposal of DOE mixed wastes. Envirocare`s RCRA Part B permit allows for the receipt, storage, treatment, and disposal of mixed wastes that do not meet the land-disposal treatment standards of 40 CFR (Code of Federal Regulations) 268. Envirocare has successfully received, managed, and disposed of naturally occurring radioactive material, low-activity radioactive waste, and mixed waste from government and private generators.

  3. Greenhouse gas emissions of waste management processes and options: A case study.

    PubMed

    de la Barrera, Belen; Hooda, Peter S

    2016-07-01

    Increasing concern about climate change is prompting organisations to mitigate their greenhouse gas emissions. Waste management activities also contribute to greenhouse gas emissions. In the waste management sector, there has been an increasing diversion of waste sent to landfill, with much emphasis on recycling and reuse to prevent emissions. This study evaluates the carbon footprint of the different processes involved in waste management systems, considering the entire waste management stream. Waste management data from the Royal Borough of Kingston upon Thames, London (UK), was used to estimate the carbon footprint for its (Royal Borough of Kingston upon Thames) current source segregation system. Second, modelled full and partial co-mingling scenarios were used to estimate carbon emissions from these proposed waste management approaches. The greenhouse gas emissions from the entire waste management system at Royal Borough of Kingston upon Thames were 12,347 t CO2e for the source-segregated scenario, and 11,907 t CO2e for the partial co-mingled model. These emissions amount to 203.26 kg CO2e t(-1) and 196.02 kg CO2e t(-1) municipal solid waste for source-segregated and partial co-mingled, respectively. The change from a source segregation fleet to a partial co-mingling fleet reduced the emissions, at least partly owing to a change in the number and type of vehicles. PMID:27236164

  4. Preliminary estimates of cost savings for defense high level waste vitrification options

    SciTech Connect

    Merrill, R.A.; Chapman, C.C.

    1993-09-01

    The potential for realizing cost savings in the disposal of defense high-level waste through process and design modificatins has been considered. Proposed modifications range from simple changes in the canister design to development of an advanced melter capable of processing glass with a higher waste loading. Preliminary calculations estimate the total disposal cost (not including capital or operating costs) for defense high-level waste to be about $7.9 billion dollars for the reference conditions described in this paper, while projected savings resulting from the proposed process and design changes could reduce the disposal cost of defense high-level waste by up to $5.2 billion.

  5. The medical waste audit. A framework for hospitals to appraise options and financial implications.

    PubMed

    Studnicki, J

    1992-03-01

    The generation, handling, and disposal of medical wastes involve virtually every department in the hospital. To enhance coordination, managers must comprehensively describe the total system and specify the roles of key functions and individuals. Hospitals produce about 77 percent of the approximately 500,000 tons of regulated medical waste produced annually in the United States. The amount produced by different hospitals varies, primarily because of differences in "waste-management practices." The Environmental Protection Agency is trying to develop a greater understanding of the types of medical wastes that are infectious, methods of transmission, and the likelihood of transmission in the handling and disposal of waste within the hospital environment. To ensure that medical waste is being handled and treated in the most cost-effective manner and with the least health risk to employees and the community, hospital administrators must undertake a comprehensive appraisal of the activities associated with the generation, handling, and disposal processes. A "medical waste audit" requires the following steps: Generation profile to identify origination points, categories or types of waste, and associated generation rates. Inventory of handling practices, including existing regulations, procedures and protocols, training programs, definitions regarding waste segregation, and documentation. Review of current disposal practices and existing and developing alternatives. Cost analysis PMID:10116509

  6. An evaluation of disposal and utilization options for advanced coal utilization wastes

    SciTech Connect

    Moretti, C.J.

    1996-05-01

    If the US is to continue to effectively use its substantial coal reserves, new clean coal technologies must be developed to improve power production efficiency and reduce emissions from power plants. In order to gain information about wastes produced by advanced coal utilization processes, a research project is being conducted to characterize the geotechnical and geochemical properties of advanced coal process wastes. The University of North Dakota Energy and Environmental Research Center (EERC) analyzed 34 of these wastes for their bulk chemical and mineral compositions and for the disposal-related physical properties listed in a table. This paper discusses potentially useful waste management practices for eight bulk waste samples obtained from four different clean coal processes: gas reburning with sorbent injection (GRSI); pressurized fluidized-bed combustion (PFBC); SO{sub x}, NO{sub x}, RO{sub x}, BOX (SNRB); and coal reburning (CR). All four processes have been demonstrated at either full-scale or pilot-scale facilities in the US. Since the properties of advanced process wastes are different from conventional coal combustion wastes, an analysis was performed to identify any potential problems that could occur when standard, off-the-shelf waste management technologies are used for handling and disposal of advanced process wastes. When potential problems were identified, possible alternative technologies were evaluated.

  7. Transboundary Movements of Hazardous Wastes. A Comparative Analysis of Policy Options to Control the International Waste Trade.

    ERIC Educational Resources Information Center

    Hilz, Christoph; Ehrenfeld, John R.

    1991-01-01

    Several policy frameworks for managing hazardous waste import/export are examined with respect to economic issues, environmental sustainability, and administrative feasibility and effectiveness. Several recommendations for improving the present instrument and implementing process are offered. (Author/CW)

  8. STABILIZATION OF LEAD-BASED PAINT WASTE

    EPA Science Inventory

    This study evaluated the ability of a cementitious stabilizing agent to reduce leachable lead from lead-based paint waste removed from substrate via blasting, and to evaluate the mechanism by which the reduction occurs. Testing demonstrated that the representative cementitious ag...

  9. WASTE REDUCTION ACTIVITIES AND OPTIONS AT A PRINTER OF FORMS AND SUPPLIES FOR THE LEGAL PROFESSION

    EPA Science Inventory

    A printer of legal forms was visited and several opportunities for waste minimization were identified. he company had already begun waste and scrap paper sorting for recycling and reuse, laundering of cleaning rags for reuse, and identification of less hazardous process-related m...

  10. Method for characterization of the redox condition of cementitious materials

    SciTech Connect

    Almond, Philip M.; Langton, Christine A.; Stefanko, David B.

    2015-12-22

    Disclosed are methods for determining the redox condition of cementitious materials. The methods are leaching methods that utilize an in situ redox indicator that is present in the cementitious materials as formed. The in situ redox indicator leaches from cementitious material and, when the leaching process is carried out under anaerobic conditions can be utilized to determine the redox condition of the material. The in situ redox indicator can exhibit distinct characteristics in the leachate depending upon the redox condition of the indicator.

  11. Flexible process options for the immobilisation of residues and wastes containing plutonium

    SciTech Connect

    Stewart, M.W.A.; Moricca, S.A.; Day, R. A.; Begg, B. D.; Scales, C. R.; Maddrell, E. R.; Eilbeck, A. B.

    2007-07-01

    Residues and waste streams containing plutonium present unique technical, safety, regulatory, security, and socio-political challenges. In the UK these streams range from lightly plutonium contaminated materials (PCM) through to residue s resulting directly from Pu processing operations. In addition there are potentially stocks of Pu oxide powders whose future designation may be either a waste or an asset, due to their levels of contamination making their reuse uneconomic, or to changes in nuclear policy. While waste management routes exist for PCM, an immobilisation process is required for streams containing higher levels of Pu. Such a process is being developed by Nexia Solutions and ANSTO to treat and immobilise Pu waste and residues currently stored on the Sellafield site. The characteristics of these Pu waste streams are highly variable. The physical form of the Pu waste ranges from liquids, sludges, powders/granules, to solid components (e.g., test fuels), with the Pu present as an ion in solution, as a salt, metal, oxide or other compound. The chemistry of the Pu waste streams also varies considerably with a variety of impurities present in many waste streams. Furthermore, with fissile isotopes present, criticality is an issue during operations and in the store or repository. Safeguards and security concerns must be assessed and controlled. The process under development, by using a combination of tailored waste form chemistry combined with flexible process technology aims to develop a process line to handle a broad range of Pu waste streams. It aims to be capable of dealing with not only current arisings but those anticipated to arise as a result of future operations or policy changes. (authors)

  12. Nanoscale characterization of engineered cementitious composites (ECC)

    SciTech Connect

    Sakulich, Aaron Richard Li, Victor C.

    2011-02-15

    Engineered cementitious composites (ECC) are ultra-ductile fiber-reinforced cementitious composites. The nanoscale chemical and mechanical properties of three ECC formulae (one standard formula, and two containing nanomaterial additives) were studied using nanoindentation, electron microscopy, and energy dispersive spectroscopy. Nanoindentation results highlight the difference in modulus between bulk matrix ({approx} 30 GPa) and matrix/fiber interfacial transition zones as well as between matrix and unreacted fly ash ({approx} 20 GPa). The addition of carbon black or carbon nanotubes produced little variation in moduli when compared to standard M45-ECC. The indents were observed by electron microscopy; no trace of the carbon black particles could be found, but nanotubes, including nanotubes bridging cracks, were easily located in ultrafine cracks near PVA fibers. Elemental analysis failed to show a correlation between modulus and chemical composition, implying that factors such as porosity have more of an effect on mechanical properties than elemental composition.

  13. Life cycle assessment of solid waste management options for Eskisehir, Turkey.

    PubMed

    Banar, Mufide; Cokaygil, Zerrin; Ozkan, Aysun

    2009-01-01

    Life cycle assessment (LCA) methodology was used to determine the optimum municipal solid waste (MSW) management strategy for Eskisehir city. Eskisehir is one of the developing cities of Turkey where a total of approximately 750tons/day of waste is generated. An effective MSW management system is needed in this city since the generated MSW is dumped in an unregulated dumping site that has no liner, no biogas capture, etc. Therefore, five different scenarios were developed as alternatives to the current waste management system. Collection and transportation of waste, a material recovery facility (MRF), recycling, composting, incineration and landfilling processes were considered in these scenarios. SimaPro7 libraries were used to obtain background data for the life cycle inventory. One ton of municipal solid waste of Eskisehir was selected as the functional unit. The alternative scenarios were compared through the CML 2000 method and these comparisons were carried out from the abiotic depletion, global warming, human toxicity, acidification, eutrophication and photochemical ozone depletion points of view. According to the comparisons and sensitivity analysis, composting scenario, S3, is the more environmentally preferable alternative. In this study waste management alternatives were investigated only on an environmental point of view. For that reason, it might be supported with other decision-making tools that consider the economic and social effects of solid waste management. PMID:18280731

  14. Life cycle assessment of solid waste management options for Eskisehir, Turkey

    SciTech Connect

    Banar, Mufide Cokaygil, Zerrin; Ozkan, Aysun

    2009-01-15

    Life cycle assessment (LCA) methodology was used to determine the optimum municipal solid waste (MSW) management strategy for Eskisehir city. Eskisehir is one of the developing cities of Turkey where a total of approximately 750 tons/day of waste is generated. An effective MSW management system is needed in this city since the generated MSW is dumped in an unregulated dumping site that has no liner, no biogas capture, etc. Therefore, five different scenarios were developed as alternatives to the current waste management system. Collection and transportation of waste, a material recovery facility (MRF), recycling, composting, incineration and landfilling processes were considered in these scenarios. SimaPro7 libraries were used to obtain background data for the life cycle inventory. One ton of municipal solid waste of Eskisehir was selected as the functional unit. The alternative scenarios were compared through the CML 2000 method and these comparisons were carried out from the abiotic depletion, global warming, human toxicity, acidification, eutrophication and photochemical ozone depletion points of view. According to the comparisons and sensitivity analysis, composting scenario, S3, is the more environmentally preferable alternative. In this study waste management alternatives were investigated only on an environmental point of view. For that reason, it might be supported with other decision-making tools that consider the economic and social effects of solid waste management.

  15. Waste Not, Want Not: Analyzing the Economic and Environmental Viability of Waste-to-Energy (WTE) Technology for Site-Specific Optimization of Renewable Energy Options

    SciTech Connect

    Funk, K.; Milford, J.; Simpkins, T.

    2013-02-01

    Waste-to-energy (WTE) technology burns municipal solid waste (MSW) in an environmentally safe combustion system to generate electricity, provide district heat, and reduce the need for landfill disposal. While this technology has gained acceptance in Europe, it has yet to be commonly recognized as an option in the United States. Section 1 of this report provides an overview of WTE as a renewable energy technology and describes a high-level model developed to assess the feasibility of WTE at a site. Section 2 reviews results from previous life cycle assessment (LCA) studies of WTE, and then uses an LCA inventory tool to perform a screening-level analysis of cost, net energy production, greenhouse gas (GHG) emissions, and conventional air pollution impacts of WTE for residual MSW in Boulder, Colorado. Section 3 of this report describes the federal regulations that govern the permitting, monitoring, and operating practices of MSW combustors and provides emissions limits for WTE projects.

  16. Investigation of separation, treatment, and recycling options for hazardous paint blast media waste. Final report

    SciTech Connect

    Boy, J.H.; Race, T.D.; Reinbold, K.A.

    1996-02-01

    U.S. Army depot depaint operations generate over 4 million kg per year of contaminated paint blast media wastes. The objective of this work was to investigate technologies that might significantly mitigate this Army hazardous waste disposal problem. Most of the technologies investigated either failed to meet acceptable TCLP levels for hazardous metals content, or failed to meet Army disposal requirements. However, based on a review of several commercially available services, it is recommended that Army depot depaint operations consider processing hazardous blast media waste through properly regulated contractors that offer safe, effective, and economical stabilization, fixation, and recycling technologies.

  17. Mobile colloid generation induced by a cementitious plume: mineral surface-charge controls on mobilization.

    PubMed

    Li, Dien; Kaplan, Daniel I; Roberts, Kimberly A; Seaman, John C

    2012-03-01

    Cementitious materials are increasingly used as engineered barriers and waste forms for radiological waste disposal. Yet their potential effect on mobile colloid generation is not well-known, especially as it may influence colloid-facilitated contaminant transport. Whereas previous papers have studied the introduction of cement colloids into sediments, this study examined the influence of cement leachate chemistry on the mobilization of colloids from a subsurface sediment collected from the Savannah River Site, USA. A sharp mobile colloid plume formed with the introduction of a cement leachate simulant. Colloid concentrations decreased to background concentrations even though the aqueous chemical conditions (pH and ionic strength) remained unchanged. Mobile colloids were mainly goethite and to a lesser extent kaolinite. The released colloids had negative surface charges and the mean particle sizes ranged primarily from 200 to 470 nm. Inherent mineralogical electrostatic forces appeared to be the controlling colloid removal mechanism in this system. In the background pH of ~6.0, goethite had a positive surface charge, whereas quartz (the dominant mineral in the immobile sediment) and kaolinite had negative surface charges. Goethite acted as a cementing agent, holding kaolinite and itself onto the quartz surfaces due to the electrostatic attraction. Once the pH of the system was elevated, as in the cementitious high pH plume front, the goethite reversed to a negative charge, along with quartz and kaolinite, then goethite and kaolinite colloids were mobilized and a sharp spike in turbidity was observed. Simulating conditions away from the cementitious source, essentially no colloids were mobilized at 1:1000 dilution of the cement leachate or when the leachate pH was ≤ 8. Extreme alkaline pH environments of cementitious leachate may change mineral surface charges, temporarily promoting the formation of mobile colloids. PMID:22316126

  18. Timing of Getter Material Addition in Cementitious Wasteforms

    NASA Astrophysics Data System (ADS)

    Lawter, A.; Qafoku, N. P.; Asmussen, M.; Neeway, J.; Smith, G. L.

    2015-12-01

    A cementitious waste form, Cast Stone, is being evaluated as a possible supplemental immobilization technology for the Hanford sites's low activity waste (LAW), which contains radioactive 99Tc and 129I, as part of the tank waste cleanup mission. Cast Stone is made of a dry blend 47% blast furnace slag, 45% fly ash, and 8% ordinary Portland cement, mixed with a low-activity waste (LAW). To improve the retention of Tc and/or I in Cast Stone, materials with a high affinity for Tc and/or I, termed "getters," can be added to provide a stable domain for the radionuclides of concern. Previous testing conducted with a variety of getters has identified Tin(II)-Apatite and Silver Exchanged Zeolite as promising candidates for Tc and I, respectively. Investigation into the sequence in which getters are added to Cast Stone was performed following two methods: 1) adding getters to the Cast Stone dry blend, and then mixing with liquid waste, and 2) adding getters to the liquid waste first, followed by addition of the Cast Stone dry blend. Cast Stone monolith samples were prepared with each method and leach tests, following EPA method 1315, were conducted in either distilled water or simulated vadose zone porewater for a period of up to 63 days. The leachate was analyzed for Tc, I, Na, NO3-, NO2- and Cr with ICP-MS, ICP-OES and ion chromatography and the results indicated that the Cast Stone with getter addition in the dry blend mix (method 1) has lower rates of Tc and I leaching. The mechanisms of radionuclide release from the Cast Stone were also investigated with a variety of solid phase characterization techniques of the monoliths before and after leaching, such as XRD, SEM/EDS, TEM/SAED and other spectroscopic techniques.

  19. Treatment options and flow sheets for ORNL low-level liquid waste supernate

    SciTech Connect

    Campbell, D.O.; Lee, D.D.

    1991-12-01

    Low-level liquid waste (LLLW) is currently contained in ten 50,000-gal storage and process tanks at Oak Ridge National Laboratory (ORNL) and as residual heels in an number of older tanks that are no longer in active use. Plans are being formulated to treat these wastes, along with similar LLLW that will be generated in the future, to yield decontaminated effluents that can be disposed of and stable solid waste forms that can be permanently stored. The primary purpose of this report is to summarize the performance of the most promising separations processes that are appropriate for treatment of the LLLW supernate solution to remove the two dominant radionuclides, {sup 137}Cs and {sup 90}Sr; to indicate how they can be integrated into an effective flowsheet; and to estimate the expected performance of such flowsheets in comparison to waste treatment requirements.

  20. Savannah River Site waste vitrification projects initiated throughout the United States: Disposal and recycle options

    SciTech Connect

    Jantzen, C.M.

    2000-04-10

    A vitrification process was developed and successfully implemented by the US Department of Energy's (DOE) Savannah River Site (SRS) and at the West Valley Nuclear Services (WVNS) to convert high-level liquid nuclear wastes (HLLW) to a solid borosilicate glass for safe long term geologic disposal. Over the last decade, SRS has successfully completed two additional vitrification projects to safely dispose of mixed low level wastes (MLLW) (radioactive and hazardous) at the SRS and at the Oak Ridge Reservation (ORR). The SRS, in conjunction with other laboratories, has also demonstrated that vitrification can be used to dispose of a wide variety of MLLW and low-level wastes (LLW) at the SRS, at ORR, at the Los Alamos National Laboratory (LANL), at Rocky Flats (RF), at the Fernald Environmental Management Project (FEMP), and at the Hanford Waste Vitrification Project (HWVP). The SRS, in conjunction with the Electric Power Research Institute and the National Atomic Energy Commission of Argentina (CNEA), have demonstrated that vitrification can also be used to safely dispose of ion-exchange (IEX) resins and sludges from commercial nuclear reactors. In addition, the SRS has successfully demonstrated that numerous wastes declared hazardous by the US Environmental Protection Agency (EPA) can be vitrified, e.g. mining industry wastes, contaminated harbor sludges, asbestos containing material (ACM), Pb-paint on army tanks and bridges. Once these EPA hazardous wastes are vitrified, the waste glass is rendered non-hazardous allowing these materials to be recycled as glassphalt (glass impregnated asphalt for roads and runways), roofing shingles, glasscrete (glass used as aggregate in concrete), or other uses. Glass is also being used as a medium to transport SRS americium (Am) and curium (Cm) to the Oak Ridge Reservation (ORR) for recycle in the ORR medical source program and use in smoke detectors at an estimated value of $1.5 billion to the general public.

  1. Thermal control of high energy nuclear waste, space option. [mathematical models

    NASA Technical Reports Server (NTRS)

    Peoples, J. A.

    1979-01-01

    Problems related to the temperature and packaging of nuclear waste material for disposal in space are explored. An approach is suggested for solving both problems with emphasis on high energy density waste material. A passive cooling concept is presented which utilized conduction rods that penetrate the inner core. Data are presented to illustrate the effectiveness of the rods and the limit of their capability. A computerized thermal model is discussed and developed for the cooling concept.

  2. Policy options to reduce consumer waste to zero: comparing product stewardship and extended producer responsibility for refrigerator waste.

    PubMed

    Nicol, Scott; Thompson, Shirley

    2007-06-01

    Today, over-consumption, pollution and resource depletion threaten sustainability. Waste management policies frequently fail to reduce consumption, prevent pollution, conserve resources and foster sustainable products. However, waste policies are changing to focus on lifecycle impacts of products from the cradle to the grave by extending the responsibilities of stakeholders to post-consumer management. Product stewardship and extended producer responsibility are two policies in use, with radically different results when compared for one consumer product, refrigerators. North America has enacted product stewardship policies that fail to require producers to take physical or financial responsibility for recycling or for environmentally sound disposal, so that releases of ozone depleting substances routinely occur, which contribute to the expanding the ozone hole. Conversely, Europe's Waste Electrical and Electronic Equipment (WEEE) Directive requires extended producer responsibility, whereby producers collect and manage their own post-consumer waste products. WEEE has resulted in high recycling rates of greater than 85%, reduced emissions of ozone-depleting substances and other toxins, greener production methods, such as replacing greenhouse gas refrigerants with environmentally friendly hydrocarbons and more reuse of refrigerators in the EU in comparison with North America. PMID:17612322

  3. Food waste conversion options in Singapore: environmental impacts based on an LCA perspective.

    PubMed

    Khoo, Hsien H; Lim, Teik Z; Tan, Reginald B H

    2010-02-15

    Proper management and recycling of huge volumes of food waste is one of the challenges faced by Singapore. Semakau island - the only offshore landfill of the nation - only accepts inert, inorganic solid waste and therefore a large bulk of food waste is directed to incinerators. A remaining small percent is sent for recycling via anaerobic digestion (AD), followed by composting of the digestate material. This article investigates the environmental performance of four food waste conversion scenarios - based on a life cycle assessment perspective - taking into account air emissions, useful energy from the incinerators and AD process, as well as carbon dioxide mitigation from the compost products derived from the digestate material and a proposed aerobic composting system. The life cycle impact results were generated for global warming, acidification, eutrophication, photochemical oxidation and energy use. The total normalized results showed that a small-scale proposed aerobic composting system is more environmentally favorable than incinerators, but less ideal compared to the AD process. By making full use of the AD's Recycling Phase II process alone, the Singapore Green Plan's 2012 aim to increase the recycling of food waste to 30% can easily be achieved, along with reduced global warming impacts. PMID:19926117

  4. Cementitious stabilization of chromium, arsenic, and selenium in a cooling tower sludge

    SciTech Connect

    Spence, R.D.; Gilliam, T.M.; Bleier, A.

    1995-06-01

    The Federal Facility Compliance Agreement (FFCA) establishes an aggressive schedule for conducting studies and treatment method development under the treatability exclusion of RCRA for those mixed wastes for which treatment methods and capabilities have yet to be defined. One of these wastes is a radioactive cooling tower sludge. This paper presents some results of a treatability study of the stabilization of this cooling tower sludge in cementitious waste forms. The sample of the cooling tower sludge obtained for this study was found to be not characteristically hazardous in regard to arsenic, barium, chromium, lead, and selenium, despite the waste codes associated with this waste. However, the scope of this study included spiking three RCRA metals to two orders of magnitude above the initial concentration to test the limits of cementitious stabilization. Chromium and arsenic were spiked at concentrations of 200, 2,000, and 20,000 mg/kg, and selenium was spiked at 100, 1,000, and 10,000 mg/kg (concentrations based on the metal in the sludge solids). Portland cement, Class F fly ash, and slag were selected as stabilizing agents in the present study. Perlite, a fine, porous volcanic rock commonly used as a filter aid, was used as a water-sorptive agent in this study in order to control bleed water for high water contents. The highly porous perlite dust absorbs large amounts of water by capillary action and does not present the handling and processing problems exhibited by clays used for bleed water control.

  5. Cementitious Barriers Partnership (CBP): Training and Release of CBP Toolbox Software, Version 1.0 - 13480

    SciTech Connect

    Brown, K.G.; Kosson, D.S.; Garrabrants, A.C.; Sarkar, S.; Flach, G.; Langton, C.; Smith, F.G. III; Burns, H.; Van der Sloot, H.; Meeussen, J.C.L.; Samson, E.; Mallick, P.; Suttora, L.; Esh, D.; Fuhrmann, M.; Philip, J.

    2013-07-01

    The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the Office of Tank Waste Management within the Office of Environmental Management of U.S. Department of Energy (US DOE). The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that improve understanding and predictions of the long-term hydraulic and chemical performance of cementitious barriers used in nuclear applications. Tools selected for and developed under this program are intended to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance up to or longer than 100 years for operating facilities and longer than 1,000 years for waste management purposes. CBP software tools were made available to selected DOE Office of Environmental Management and field site users for training and evaluation based on a set of important degradation scenarios, including sulfate ingress/attack and carbonation of cementitious materials. The tools were presented at two-day training workshops held at U.S. National Institute of Standards and Technology (NIST), Savannah River, and Hanford included LeachXS{sup TM}/ORCHESTRA, STADIUM{sup R}, and a CBP-developed GoldSim Dashboard interface. Collectively, these components form the CBP Software Toolbox. The new U.S. Environmental Protection Agency leaching test methods based on the Leaching Environmental Assessment Framework (LEAF) were also presented. The CBP Dashboard uses a custom Dynamic-link library developed by CBP to couple to the LeachXS{sup TM}/ORCHESTRA and STADIUM{sup R} codes to simulate reactive transport and degradation in cementitious materials for selected performance assessment scenarios. The first day of the workshop introduced participants to the software components via presentation materials, and the second day included hands-on tutorial exercises followed

  6. Uranium-233 waste definition: Disposal options, safeguards, criticality control, and arms control

    SciTech Connect

    Forsberg, C.W.; Storch, S.N.; Lewis, L.C.

    1998-07-07

    The US investigated the use of {sup 233}U for weapons, reactors, and other purposes from the 1950s into the 1970s. Based on the results of these investigations, it was decided not to use {sup 233}U on a large scale. Most of the {sup 233}U-containing materials were placed in long-term storage. At the end of the cold war, the US initiated, as part of its arms control policies, a disposition program for excess fissile materials. Other programs were accelerated for disposal of radioactive wastes placed in storage during the cold war. Last, potential safety issues were identified related to the storage of some {sup 233}U-containing materials. Because of these changes, significant activities associated with {sup 233}U-containing materials are expected. This report is one of a series of reports to provide the technical bases for future decisions on how to manage this material. A basis for defining when {sup 233}U-containing materials can be managed as waste and when they must be managed as concentrated fissile materials has been developed. The requirements for storage, transport, and disposal of radioactive wastes are significantly different than those for fissile materials. Because of these differences, it is important to classify material in its appropriate category. The establishment of a definition of what is waste and what is fissile material will provide the guidance for appropriate management of these materials. Wastes are defined in this report as materials containing sufficiently small masses or low concentrations of fissile materials such that they can be managed as typical radioactive waste. Concentrated fissile materials are defined herein as materials containing sufficient fissile content such as to warrant special handling to address nuclear criticality, safeguards, and arms control concerns.

  7. Offsite commercial disposal of oil and gas exploration and production waste :availability, options, and cost.

    SciTech Connect

    Puder, M. G.; Veil, J. A.

    2006-09-05

    A survey conducted in 1995 by the American Petroleum Institute (API) found that the U.S. exploration and production (E&P) segment of the oil and gas industry generated more than 149 million bbl of drilling wastes, almost 18 billion bbl of produced water, and 21 million bbl of associated wastes. The results of that survey, published in 2000, suggested that 3% of drilling wastes, less than 0.5% of produced water, and 15% of associated wastes are sent to offsite commercial facilities for disposal. Argonne National Laboratory (Argonne) collected information on commercial E&P waste disposal companies in different states in 1997. While the information is nearly a decade old, the report has proved useful. In 2005, Argonne began collecting current information to update and expand the data. This report describes the new 2005-2006 database and focuses on the availability of offsite commercial disposal companies, the prevailing disposal methods, and estimated disposal costs. The data were collected in two phases. In the first phase, state oil and gas regulatory officials in 31 states were contacted to determine whether their agency maintained a list of permitted commercial disposal companies dedicated to oil. In the second stage, individual commercial disposal companies were interviewed to determine disposal methods and costs. The availability of offsite commercial disposal companies and facilities falls into three categories. The states with high oil and gas production typically have a dedicated network of offsite commercial disposal companies and facilities in place. In other states, such an infrastructure does not exist and very often, commercial disposal companies focus on produced water services. About half of the states do not have any industry-specific offsite commercial disposal infrastructure. In those states, operators take their wastes to local municipal landfills if permitted or haul the wastes to other states. This report provides state-by-state summaries of the

  8. Non-cementitious compositions comprising vaterite and methods thereof

    SciTech Connect

    Devenney, Martin; Fernandez, Miguel; Morgan, Samuel O.

    2015-09-15

    Non-cementitious compositions and products are provided. The compositions of the invention include a carbonate additive comprising vaterite such as reactive vaterite. Additional aspects of the invention include methods of making and using the non-cementitious compositions and products.

  9. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF ORTHOPEDIC IMPLANTS.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of th...

  10. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A TRANSPORTER OF BULK PLASTIC PELLETS.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of th...

  11. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF ARTISTS' SUPPLY PAINTS.

    EPA Science Inventory

    The Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small to medium sized businesses in the state of New Jersey. One of the sites...

  12. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF HARDENED STEEL GEARS.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small to medium sized businesses in the state of New Jersey. One of the...

  13. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF WRITING INSTRUMENTS.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of th...

  14. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A NUCLEAR POWERED ELECTRICAL GENERATING STATION.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of th...

  15. WASTE REDUCTION ACTIVITIES AND OPTIONS AT A PRINTER OF FORMS AND SUPPLIES FOR THE LEGAL PROFESSION

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small-to medium-sized businesses in the state of New Jersey. One of the ...

  16. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF COMMERCIAL REFRIGERATION UNITS.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of the...

  17. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A REMANUFACTURER OF AUTOMOBILE RADIATORS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  18. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A REMANUFACTURER OF AUTOMOBILE RADIATORS.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  19. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR AN AUTOBODY REPAIR FACILITY

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  20. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A SCRAP METAL RECOVERY FACILITY

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  1. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A SCRAP METAL RECOVERY FACILITY.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of the...

  2. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR AN AUTOBODY REPAIR FACILITY.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of the...

  3. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A LAMINATOR OF PAPER AND CARDBOARD PACKAGES.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of th...

  4. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF SYSTEMS TO PRODUCE SEMICONDUCTORS.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  5. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A TRANSPORTER OF BULK PLASTIC PELLETS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  6. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF ELECTROPLATED WIRE.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of the...

  7. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF HARDENED STEEL GEARS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  8. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A NUCLEAR POWERED ELECTRICAL GENERATING STATION

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  9. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A STATE DEPARTMENT OF TRANSPORTATION.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the State of New Jersey. One of th...

  10. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF ELECTROPLATED WIRE

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  11. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF SYSTEMS TO PRODUCE SEMICONDUCTORS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  12. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF ORTHOPEDIC IMPLANTS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  13. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF FINISHED LEATHER

    EPA Science Inventory

    The U.S.Environmental Protection Agency (EPA) funded a project with the Hew Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the s...

  14. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF FINISHED LEATHER.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of th...

  15. Evaluating and planning the radioactive waste options for dismantling the Tokamak Fusion Test Reactor

    SciTech Connect

    Rule, K.; Scott, J.; Larson, S.

    1995-12-31

    The Tokamak Fusion Test Reactor (TFTR) is a one-of-a kind tritium fusion research reactor, and is planned to be decommissioned within the next several years. This is the largest fusion reactor in the world and as a result of deuterium-tritum reactions is tritium contaminated and activated from 14 Mev neutrons. This presents many unusual challenges when dismantling, packaging and disposing its components and ancillary systems. Special containers are being designed to accommodate the vacuum vessel, neutral beams, and tritium delivery and processing systems. A team of experienced professionals performed a detailed field study to evaluate the requirements and appropriate methods for packaging the radioactive materials. This team focused on several current and innovative methods for waste minimization that provides the oppurtunmost cost effective manner to package and dispose of the waste. This study also produces a functional time-phased schedule which conjoins the waste volume, weight, costs and container requirements with the detailed project activity schedule for the entire project scope. This study and project will be the first demonstration of the decommissioning of a tritium fusion test reactor. The radioactive waste disposal aspects of this project are instrumental in demonstrating the viability of a fusion power reactor with regard to its environmental impact and ultimate success.

  16. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF COMMERCIAL DRY CLEANING EQUIPMENT.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of th...

  17. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF ELECTROPLATING CHEMICAL PRODUCTS.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of th...

  18. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A LAMINATOR OF PAPER AND CARDBOARD PACKAGES

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  19. Hydration characteristics and environmental friendly performance of a cementitious material composed of calcium silicate slag.

    PubMed

    Zhang, Na; Li, Hongxu; Zhao, Yazhao; Liu, Xiaoming

    2016-04-01

    Calcium silicate slag is an alkali leaching waste generated during the process of extracting Al2O3 from high-alumina fly ash. In this research, a cementitious material composed of calcium silicate slag was developed, and its mechanical and physical properties, hydration characteristics and environmental friendly performance were investigated. The results show that an optimal design for the cementitious material composed of calcium silicate slag was determined by the specimen CFSC7 containing 30% calcium silicate slag, 5% high-alumina fly ash, 24% blast furnace slag, 35% clinker and 6% FGD gypsum. This blended system yields excellent physical and mechanical properties, confirming the usefulness of CFSC7. The hydration products of CFSC7 are mostly amorphous C-A-S-H gel, rod-like ettringite and hexagonal-sheet Ca(OH)2 with small amount of zeolite-like minerals such as CaAl2Si2O8·4H2O and Na2Al2Si2O8·H2O. As the predominant hydration products, rod-like ettringite and amorphous C-A-S-H gel play a positive role in promoting densification of the paste structure, resulting in strength development of CFSC7 in the early hydration process. The leaching toxicity and radioactivity tests results indicate that the developed cementitious material composed of calcium silicate slag is environmentally acceptable. This study points out a promising direction for the proper utilization of calcium silicate slag in large quantities. PMID:26691955

  20. Process Options Description for Vitrification Flowsheet Model of INEEL Sodium Bearing Waste

    SciTech Connect

    Nichols, Todd Travis; Taylor, Dean Dalton; Lauerhass, Lance; Barnes, Charles Marshall

    2001-02-01

    The purpose of this document is to provide the technical information to Savannah River Site (SRS) personnel that is required for the development of a basic steady-state process simulation of the vitrification treatment train of sodium bearing waste (SBW) at Idaho National Engineering and nvironmental Laboratory (INEEL). INEEL considers simulation to have an important role in the integration/optimization of treatment process trains for the High Level Waste (HLW) Program. This project involves a joint Technical Task Plan (TTP ID77WT31, Subtask C) between SRS and INEEL. The work scope of simulation is different at the two sites. This document addresses only the treatment of SBW at INEEL. The simulation model(s) is to be built by SRS for INEEL in FY-2001.

  1. Tailoring engineered cementitious composites for impact resistance

    SciTech Connect

    Yang, En-Hua; Li, Victor C.

    2012-08-15

    This paper presents results of deliberate tailoring of engineered cementitious composites (ECC) for impact resistance. Microstructure control involving fiber, matrix and fiber/matrix interface was based on steady-state dynamic crack growth analyses accounting for rate dependence of composite phases. Uniaxial tensile stress-strain curves of the resulting impact resistant ECC were experimentally determined for strain rates ranging from 10{sup -5} s{sup -1} to 10{sup -1} s{sup -1}. Low speed drop weight tower test on ECC panels and beams was also conducted. Damage characteristics, load and energy dissipation capacities, and response to repeated impacts, were studied.

  2. Self-degradable Cementitious Sealing Materials

    SciTech Connect

    Sugama, T.; Butcher, T., Lance Brothers, Bour, D.

    2010-10-01

    A self-degradable alkali-activated cementitious material consisting of a sodium silicate activator, slag, Class C fly ash, and sodium carboxymethyl cellulose (CMC) additive was formulated as one dry mix component, and we evaluated its potential in laboratory for use as a temporary sealing material for Enhanced Geothermal System (EGS) wells. The self-degradation of alkali-activated cementitious material (AACM) occurred, when AACM heated at temperatures of {ge}200 C came in contact with water. We interpreted the mechanism of this water-initiated self-degradation as resulting from the in-situ exothermic reactions between the reactants yielded from the dissolution of the non-reacted or partially reacted sodium silicate activator and the thermal degradation of the CMC. The magnitude of self-degradation depended on the CMC content; its effective content in promoting degradation was {ge}0.7%. In contrast, no self-degradation was observed from CMC-modified Class G well cement. For 200 C-autoclaved AACMs without CMC, followed by heating at temperatures up to 300 C, they had a compressive strength ranging from 5982 to 4945 psi, which is {approx}3.5-fold higher than that of the commercial Class G well cement; the initial- and final-setting times of this AACM slurry at 85 C were {approx}60 and {approx}90 min. Two well-formed crystalline hydration phases, 1.1 nm tobermorite and calcium silicate hydrate (I), were responsible for developing this excellent high compressive strength. Although CMC is an attractive, as a degradation-promoting additive, its addition to both the AACM and the Class G well cement altered some properties of original cementitious materials; among those were an extending their setting times, an increasing their porosity, and lowering their compressive strength. Nevertheless, a 0.7% CMC-modified AACM as self-degradable cementitious material displayed the following properties before its breakdown by water; {approx}120 min initial- and {approx}180 min final

  3. An integrated appraisal of energy recovery options in the United Kingdom using solid recovered fuel derived from municipal solid waste

    SciTech Connect

    Garg, A.; Smith, R.; Hill, D.; Simms, N.J.

    2009-08-15

    This paper reports an integrated appraisal of options for utilising solid recovered fuels (SRF) (derived from municipal solid waste, MSW) in energy intensive industries within the United Kingdom (UK). Four potential co-combustion scenarios have been identified following discussions with industry stakeholders. These scenarios have been evaluated using (a) an existing energy and mass flow framework model, (b) a semi-quantitative risk analysis, (c) an environmental assessment and (d) a financial assessment. A summary of results from these evaluations for the four different scenarios is presented. For the given ranges of assumptions; SRF co-combustion with coal in cement kilns was found to be the optimal scenario followed by co-combustion of SRF in coal-fired power plants. The biogenic fraction in SRF (ca. 70%) reduces greenhouse gas (GHG) emissions significantly ({approx}2500 g CO{sub 2} eqvt./kg DS SRF in co-fired cement kilns and {approx}1500 g CO{sub 2} eqvt./kg DS SRF in co-fired power plants). Potential reductions in electricity or heat production occurred through using a lower calorific value (CV) fuel. This could be compensated for by savings in fuel costs (from SRF having a gate fee) and grants aimed at reducing GHG emission to encourage the use of fuels with high biomass fractions. Total revenues generated from coal-fired power plants appear to be the highest ( Pounds 95/t SRF) from the four scenarios. However overall, cement kilns appear to be the best option due to the low technological risks, environmental emissions and fuel cost. Additionally, cement kiln operators have good experience of handling waste derived fuels. The scenarios involving co-combustion of SRF with MSW and biomass were less favourable due to higher environmental risks and technical issues.

  4. An integrated appraisal of energy recovery options in the United Kingdom using solid recovered fuel derived from municipal solid waste.

    PubMed

    Garg, A; Smith, R; Hill, D; Longhurst, P J; Pollard, S J T; Simms, N J

    2009-08-01

    This paper reports an integrated appraisal of options for utilising solid recovered fuels (SRF) (derived from municipal solid waste, MSW) in energy intensive industries within the United Kingdom (UK). Four potential co-combustion scenarios have been identified following discussions with industry stakeholders. These scenarios have been evaluated using (a) an existing energy and mass flow framework model, (b) a semi-quantitative risk analysis, (c) an environmental assessment and (d) a financial assessment. A summary of results from these evaluations for the four different scenarios is presented. For the given ranges of assumptions; SRF co-combustion with coal in cement kilns was found to be the optimal scenario followed by co-combustion of SRF in coal-fired power plants. The biogenic fraction in SRF (ca. 70%) reduces greenhouse gas (GHG) emissions significantly ( approximately 2500 g CO(2) eqvt./kg DS SRF in co-fired cement kilns and approximately 1500 g CO(2) eqvt./kg DS SRF in co-fired power plants). Potential reductions in electricity or heat production occurred through using a lower calorific value (CV) fuel. This could be compensated for by savings in fuel costs (from SRF having a gate fee) and grants aimed at reducing GHG emission to encourage the use of fuels with high biomass fractions. Total revenues generated from coal-fired power plants appear to be the highest ( 95 pounds/t SRF) from the four scenarios. However overall, cement kilns appear to be the best option due to the low technological risks, environmental emissions and fuel cost. Additionally, cement kiln operators have good experience of handling waste derived fuels. The scenarios involving co-combustion of SRF with MSW and biomass were less favourable due to higher environmental risks and technical issues. PMID:19443201

  5. Final disposal options for mercury/uranium mixed wastes from the Oak Ridge Reservation

    SciTech Connect

    Gorin, A.H.; Leckey, J.H.; Nulf, L.E.

    1994-08-29

    Laboratory testing was completed on chemical stabilization and physical encapsulation methods that are applicable (to comply with federal and state regulations) to the final disposal of both hazardous and mixed hazardous elemental mercury waste that is in either of the following categories: (1) waste generated during decontamination and decommissioning (D and D) activities on mercury-contaminated buildings, such as Building 9201-4 at the Oak Ridge Y-12 Plant, or (2) waste stored and regulated under either the Federal Facilities Compliance Agreement or the Federal Facilities Compliance Act. Methods were used that produced copper-mercury, zinc-mercury, and sulfur-mercury materials at room temperature by dry mixing techniques. Toxicity Characteristic Leaching Procedure (TCLP) results for mercury on batches of both the copper-mercury and the sulfur-mercury amalgams consistently produced leachates with less than the 0.2-mg/L Resource Conservation and Recovery Act (RCRA) regulatory limit for mercury. The results clearly showed that the reaction of mercury with sulfur at room temperature produces black mercuric sulfide, a material that is well suited for land disposal. The results also showed that the copper-mercury and zinc-mercury amalgams had major adverse properties that make them undesirable for land disposal. In particular, they reacted readily in air to form oxides and liberate elemental mercury. Another major finding of this study is that sulfur polymer cement is potentially useful as a physical encapsulating agent for mercuric sulfide. This material provides a barrier in addition to the chemical stabilization that further prevents mercury, in the form of mercuric sulfide, from migrating into the environment.

  6. The Expanded Capabilities Of The Cementitious Barriers Partnership Software Toolbox Version 2.0 - 14331

    SciTech Connect

    Burns, Heather; Flach, Greg; Smith, Frank; Langton, Christine; Brown, Kevin; Kosson, David; Samson, Eric; Mallick, Pramod

    2014-01-10

    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 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. The CBP Software Toolbox – “Version 1.0” was released early in FY2013 and was used to support DOE-EM performance assessments in evaluating various degradation mechanisms that included sulfate attack, carbonation and constituent leaching. The sulfate attack analysis predicted the extent and damage that sulfate ingress will have on concrete vaults over extended time (i.e., > 1000 years) and the carbonation analysis provided concrete degradation predictions from rebar corrosion. The new release “Version 2.0” includes upgraded carbonation software and a new software module to evaluate degradation due to chloride attack. Also included in the newer version are a dual regime module allowing evaluation of contaminant release in two regimes – both fractured and un-fractured. The integrated software package has also been upgraded with new plotting capabilities and many other features that increase the “user-friendliness” of the package. Experimental work has been generated to provide data to calibrate the models to improve the credibility of the analysis and reduce the uncertainty. 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 to or longer than 100 years for operating facilities and longer than 1000 years for waste disposal. The CBP Software Toolbox is and will continue to produce tangible benefits to the working DOE

  7. Analysis of Graphite-Reinforced Cementitious Composites

    NASA Technical Reports Server (NTRS)

    Vaughan, R. E.

    2002-01-01

    Strategically embedding graphite meshes in a compliant cementitious matrix produces a composite material with relatively high tension and compressive properties as compared to steel-reinforced structures fabricated from a standard concrete mix. Although these composite systems are somewhat similar, the methods used to analyze steel-reinforced composites often fail to characterize the behavior of their more advanced graphite-reinforced counterparts. This Technical Memorandum describes some of the analytical methods being developed to determine the deflections and stresses in graphite-reinforced cementitious composites. It is initially demonstrated that the standard transform section method fails to provide accurate results when the elastic moduli ratio exceeds 20. An alternate approach is formulated by using the rule of mixtures to determine a set of effective material properties for the composite. Tensile tests are conducted on composite samples to verify this approach. When the effective material properties are used to characterize the deflections of composite beams subjected to pure bending, an excellent agreement is obtained. Laminated composite plate theory is investigated as a means for analyzing even more complex composites, consisting of multiple graphite layers oriented in different directions. In this case, composite beams are analyzed using the laminated composite plate theory with material properties established from tensile tests. Then, finite element modeling is used to verify the results. Considering the complexity of the samples, a very good agreement is obtained.

  8. REVIEW OF ALTERNATIVE ENHANCED CHEMICAL CLEANING OPTIONS FOR SRS WASTE TANKS

    SciTech Connect

    Hay, M.; Koopman, D.

    2009-08-01

    A literature review was conducted to support the Task Technical and Quality Assurance Plan for Alternative Enhanced Chemical Cleaning (AECC) for sludge heel removal funded as part of the EM-21 Engineering and Technology program. The goal was to identify potential technologies or enhancements to the baseline oxalic acid cleaning process for chemically dissolving or mobilizing Savannah River Site (SRS) sludge heels. The issues with the potentially large volume of oxalate solids generated from the baseline process have driven an effort to find an improved or enhanced chemical cleaning technology for the tank heels. This literature review builds on a previous review conducted in 2003. A team was charged with evaluating the information in these reviews and developing recommendations of alternative technologies to pursue. The new information in this report supports the conclusion of the previous review that oxalic acid remains the chemical cleaning agent of choice for dissolving the metal oxides and hydroxides found in sludge heels in carbon steel tanks. The potential negative impact of large volumes of sodium oxalate on downstream processes indicates that the amount of oxalic acid used for chemical cleaning needs to be minimized as much as possible or the oxalic acid must be destroyed prior to pH adjustment in the receipt tank. The most straightforward way of minimizing the volume of oxalic acid needed for chemical cleaning is through more effective mechanical cleaning. Using a mineral acid to adjust the pH of the sludge prior to adding oxalic acid may also help to minimize the volume of oxalic acid used in chemical cleaning. If minimization of oxalic acid proves insufficient in reducing the volume of oxalate salts, several methods were found that could be used for oxalic acid destruction. For some waste tank heels, another acid or even caustic treatment (or pretreatment) might be more appropriate than the baseline oxalic acid cleaning process. Caustic treatment of high

  9. Process Options Description for Steam Reforming Flowsheet Model of INEEL Tank Farm Waste

    SciTech Connect

    Taylor, D.D.; Barnes, C.M.; Nichols, T.T.

    2002-05-21

    Technical information is provided herein that is required for development of a steady-state process simulation of a baseline steam reforming treatment train for Tank Farm waste at the Idaho National Engineering and Environmental Laboratory (INEEL). This document supercedes INEEL/EXT-2001-173, produced in FY2001 to support simulation of the direct vitrification treatment train which was the previous process baseline. A process block flow diagram for steam reforming is provided, together with a list of unit operations which constitute the process. A detailed description of each unit operation is given which includes its purpose, principal phenomena present, expected pressure and temperature ranges, key chemical species in the inlet steam, and the proposed manner in which the unit operation is to be modeled in the steady state process simulation. Models for the unit operations may be mechanistic (based on first principles), empirical (based solely on pilot test data without extrapolation) , or by correlations (based on extrapolative or statistical schemes applied to pilot test data). Composition data for the expected process feed streams is provided.

  10. Nuclear heating, radiation damage, and waste management options for the HYLIFE-II final focus magnets

    SciTech Connect

    Latkowski, J F; Moir, R W; House, P A

    1999-08-09

    Heavy-ion fusion (HIF) designs for inertial fusion energy (XFE) power plants typically require final focusing magnets just outside the reaction chamber and blanket. Due to penetrations within the chamber and blanket, the magnets are exposed to a radiation environment. Although the magnet bores would be sized to avoid line-of-sight irradiation, the magnets still would be susceptible to nuclear heating and radiation damage from neutrons and y-rays. Additionally, the magnets must be included in waste management considerations due to neutron activation. Modified versions of the HYLIFE-II IFE power plant featuring two-sided illumination by arrays of 32 or 96 beams from each side are presented. A simple, point-of-departure quadrupole magnet design is assumed, and a three-dimensional neutronics model is created for the Flibe pocket, first wall, blanket, shield, and final two focusing magnets. This work details state-of-the-art neutronics calculations and shows that the final focus system needs to be included in the economic and environmental considerations for the driver-chamber interface of any HIF IFE power plant design.

  11. Process Options Description for Vitrification Flowsheet Model of INEEL Sodium Bearing Waste

    SciTech Connect

    Nichols, T.T.; Taylor, D.D.; Lauerhass, L.; Barnes, C.M.

    2002-02-21

    The technical information required for the development of a basic steady-state process simulation of the vitrification treatment train of sodium bearing waste (SBW) at Idaho National Engineering and Environmental Laboratory (INEEL) is presented. The objective of the modeling effort is to provide the predictive capability required to optimize an entire treatment train and assess system-wide impacts of local changes at individual unit operations, with the aim of reducing the schedule and cost of future process/facility design efforts. All the information required a priori for engineers to construct and link unit operation modules in a commercial software simulator to represent the alternative treatment trains is presented. The information is of a mid- to high-level nature and consists of the following: (1) a description of twenty-four specific unit operations--their operating conditions and constraints, primary species and key outputs, and the initial modeling approaches that will be used in the first year of the simulation's development; (2) three potential configurations of the unit operations (trains) and their interdependencies via stream connections; and (3) representative stream compositional makeups.

  12. Architecture for gas transport through cementitious materials

    NASA Astrophysics Data System (ADS)

    Vu, Thai Hoa; Frizon, Fabien; Lorente, Sylvie

    2009-05-01

    This paper documents the transport of gaseous species through porous media, with application to cementitious materials. An artificial pore network was created based on mercury intrusion porometry results obtained with samples of cement paste. The flow architecture model consists of parallel channels made of assemblies of truncated cones. Gas diffusion is described as a function of the saturation degree of the material. The model accounts for the effects of the liquid curtains, and the impact of tortuosity on gas diffusion. The results show that constructing an artificial architecture based on Hg porometry allows us to describe with a good accuracy the material porous network. The liquid curtains operate as an obstacle to H2 diffusion. They are determined as a function of the water saturation level and the pore channels geometry. Furthermore, the role of tortuosity as an indicator of gas diffusion accessibility is captured. The sudden drop in the effective diffusion coefficient around a saturation degree of 70% is predicted accurately.

  13. Analysis of Graphite Reinforced Cementitious Composites

    NASA Technical Reports Server (NTRS)

    Vaughan, Robert E.; Gilbert, John A.; Spanyer, Karen (Technical Monitor)

    2001-01-01

    This paper describes analytical methods that can be used to determine the deflections and stresses in highly compliant graphite-reinforced cementitious composites. It is demonstrated that the standard transform section fails to provide accurate results when the elastic modulus ratio exceeds 20. So an alternate approach is formulated by using the rule of mixtures to determine a set of effective material properties for the composite. Tensile tests are conducted on composite samples to verify this approach; and, when the effective material properties are used to characterize the deflections of composite beams subject to pure bending, an excellent agreement is obtained. Laminated composite plate theory is also investigated as a means for analyzing even more complex composites, consisting of multiple graphite layers oriented in different directions. In this case, composite beams are analyzed by incorporating material properties established from tensile tests. Finite element modeling is used to verity the results and, considering the complexity of the samples, a very good agreement is obtained.

  14. TANK SPACE OPTIONS REPORT

    SciTech Connect

    WILLIS WL; AHRENDT MR

    2009-08-11

    Since this report was originally issued in 2001, several options proposed for increasing double-shell tank (DST) storage space were implemented or are in the process of implementation. Changes to the single-shell tank (SST) waste retrieval schedule, completion of DST space saving options, and the DST space saving options in progress have delayed the projected shortfall of DST storage space from the 2007-2011 to the 2018-2025 timeframe (ORP-11242, River Protection Project System Plan). This report reevaluates options from Rev. 0 and includes evaluations of new options for alleviating projected restrictions on SST waste retrieval beginning in 2018 because of the lack of DST storage space.

  15. Studies of ancient concrete as analogs of cementitious sealing materials for a repository in tuff

    SciTech Connect

    Roy, D.M.; Langton, C.A.

    1989-03-01

    The durability of ancient cementitious materials has been investigated to provide data applicable to determining the resistance to weathering of concrete materials for sealing a repository for storage of high-level radioactive waste. Because tuff and volcanic ash are used in the concretes in the vicinity of Rome, the results are especially applicable to a waste repository in tuff. Ancient mortars, plasters, and concretes collected from Rome, Ostia, and Cosa dating to the third century BC show remarkable durability. The aggregates used in the mortars, plasters, and concretes included basic volcanic and pyroclastic rocks (including tuff), terra-cotta, carbonates, sands, and volcanic ash. The matrices of ancient cementitious materials have been characterized and classified into four categories: (1) hydraulic hydrated lime and hydrated lime cements, (2) hydraulic aluminous and ferruginous hydrated lime cements ({plus_minus} siliceous components), (3) pozzolana/hydrated lime cements, and (4) gypsum cements. Most of the materials investigated are in category (3). The materials were characterized to elucidate aspects of the technology that produced them and their response to the environmental exposure throughout their centuries of existence. Their remarkable properties are the result of a combination of chemical, mineralogical, and microstructural factors. Their durability was found to be affected by the matrix mineralogy, particle size, and porosity; aggregate type, grading and proportioning; and the methodology of placement. 30 refs.

  16. Helping lower income parents reduce the risk of food waste resulting from children's aversion to healthier food options: Comment on Daniel (2016).

    PubMed

    Connell, Paul M; Finkelstein, Stacey R; Scott, Maura L; Vallen, Beth

    2016-02-01

    We reflect on Daniel's (2016) finding that a challenge to improving the diets of lower income children is parental worry over food waste that results from children's rejection of healthier food options such as vegetables. This finding has important implications because previous research has indicated novel foods that have a bitter or sour flavor profile (as is the case with many vegetables) must be introduced to children several times before these foods are accepted. We suggest research-based techniques that parents could utilize to reduce the risk of costly food waste, and discuss obstacles that could impede well-intended parents from reaching their goals of improving their children's diets. PMID:26723199

  17. Temporary Cementitious Sealers in Enhanced Geothermal Systems

    SciTech Connect

    Sugama T.; Pyatina, T.; Butcher, T.; Brothers, L.; Bour, D.

    2011-12-31

    Unlike conventional hydrothennal geothermal technology that utilizes hot water as the energy conversion resources tapped from natural hydrothermal reservoir located at {approx}10 km below the ground surface, Enhanced Geothermal System (EGS) must create a hydrothermal reservoir in a hot rock stratum at temperatures {ge}200 C, present in {approx}5 km deep underground by employing hydraulic fracturing. This is the process of initiating and propagating a fracture as well as opening pre-existing fractures in a rock layer. In this operation, a considerable attention is paid to the pre-existing fractures and pressure-generated ones made in the underground foundation during drilling and logging. These fractures in terms of lost circulation zones often cause the wastage of a substantial amount of the circulated water-based drilling fluid or mud. Thus, such lost circulation zones must be plugged by sealing materials, so that the drilling operation can resume and continue. Next, one important consideration is the fact that the sealers must be disintegrated by highly pressured water to reopen the plugged fractures and to promote the propagation of reopened fractures. In response to this need, the objective of this phase I project in FYs 2009-2011 was to develop temporary cementitious fracture sealing materials possessing self-degradable properties generating when {ge} 200 C-heated scalers came in contact with water. At BNL, we formulated two types of non-Portland cementitious systems using inexpensive industrial by-products with pozzolanic properties, such as granulated blast-furnace slag from the steel industries, and fly ashes from coal-combustion power plants. These byproducts were activated by sodium silicate to initiate their pozzolanic reactions, and to create a cemetitious structure. One developed system was sodium silicate alkali-activated slag/Class C fly ash (AASC); the other was sodium silicate alkali-activated slag/Class F fly ash (AASF) as the binder of temper

  18. Mechanisms of cementitious material deterioration in biogas digester.

    PubMed

    Voegel, C; Bertron, A; Erable, B

    2016-11-15

    Digesters produce biogas from organic wastes through anaerobic digestion processes. These digesters, often made of concrete, suffer severe premature deterioration caused mainly by the presence of fermentative microorganisms producing metabolites that are aggressive towards cementitious materials. To clarify the degradation mechanisms in an anaerobic digestion medium, ordinary Portland cement paste specimens were immersed in the liquid fraction of a running, lab-scale digester for 4weeks. The anaerobic digestion medium was a mixture of a biowaste substrate and sludge from municipal wastewater treatment plant used as a source of anaerobic bacteria. The chemical characteristics of the anaerobic digestion liquid phase were monitored over time using a pH metre, high performance liquid chromatography (HPLC) and ion chromatography (HPIC). An initial critical period of low pH in the bioreactors was observed before the pH stabilized around 8. Acetic, propionic and butyric acids were produced during the digestion with a maximum total organic acid concentration of 50mmolL(-1). The maximum ammonium content of the liquid phase was 40mmolL(-1), which was about seven times the upper limit of the highly aggressive chemical environment class (XA3) as defined by the European standard for the specification of concrete design in chemically aggressive environments (EN 206). The changes in the mineralogical, microstructural and chemical characteristics of the cement pastes exposed to the solid and liquid phase of the digesters were analysed at the end of the immersion period by X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDS) and electron-probe micro-analysis (EPMA). A 700-μm thick altered layer was identified in the cement paste specimens. The main biodeterioration patterns in the bioreactors' solid/liquid phase were calcium leaching and carbonation of the cement matrix. PMID:27432729

  19. Bond strength of cementitious borehole plugs in welded tuff

    SciTech Connect

    Akgun, H.; Daemen, J.J.K.

    1991-02-01

    Axial loads on plugs or seals in an underground repository due to gas, water pressures and temperature changes induced subsequent to waste and plug emplacement lead to shear stresses at the plug/rock contact. Therefore, the bond between the plug and rock is a critical element for the design and effectiveness of plugs in boreholes, shafts or tunnels. This study includes a systematic investigation of the bond strength of cementitious borehole plugs in welded tuff. Analytical and numerical analysis of borehole plug-rock stress transfer mechanics is performed. The interface strength and deformation are studied as a function of Young`s modulus ratio of plug and rock, plug length and rock cylinder outside-to-inside radius ratio. The tensile stresses in and near an axially loaded plug are analyzed. The frictional interface strength of an axially loaded borehole plug, the effect of axial stress and lateral external stress, and thermal effects are also analyzed. Implications for plug design are discussed. The main conclusion is a strong recommendation to design friction plugs in shafts, drifts, tunnels or boreholes with a minimum length to diameter ratio of four. Such a geometrical design will reduce tensile stresses in the plug and in the host rock to a level which should minimize the risk of long-term deterioration caused by excessive tensile stresses. Push-out tests have been used to determine the bond strength by applying an axial load to cement plugs emplaced in boreholes in welded tuff cylinders. A total of 130 push-out tests have been performed as a function of borehole size, plug length, temperature, and degree of saturation of the host tuff. The use of four different borehole radii enables evaluation of size effects. 119 refs., 42 figs., 20 tabs.

  20. Micro- and macroscale coefficients of friction of cementitious materials

    SciTech Connect

    Lomboy, Gilson; Sundararajan, Sriram; Wang, Kejin

    2013-12-15

    Millions of metric tons of cementitious materials are produced, transported and used in construction each year. The ease or difficulty of handling cementitious materials is greatly influenced by the material friction properties. In the present study, the coefficients of friction of cementitious materials were measured at the microscale and macroscale. The materials tested were commercially-available Portland cement, Class C fly ash, and ground granulated blast furnace slag. At the microscale, the coefficient of friction was determined from the interaction forces between cementitious particles using an Atomic Force Microscope. At the macroscale, the coefficient of friction was determined from stresses on bulk cementitious materials under direct shear. The study indicated that the microscale coefficient of friction ranged from 0.020 to 0.059, and the macroscale coefficient of friction ranged from 0.56 to 0.75. The fly ash studied had the highest microscale coefficient of friction and the lowest macroscale coefficient of friction. -- Highlights: •Microscale (interparticle) coefficient of friction (COF) was determined with AFM. •Macroscale (bulk) COF was measured under direct shear. •Fly ash had the highest microscale COF and the lowest macroscale COF. •Portland cement against GGBFS had the lowest microscale COF. •Portland cement against Portland cement had the highest macroscale COF.

  1. Cementitious Barriers Partnership (CBP): Using the CBP Software Toolbox to Simulate Sulfate Attack and Carbonation of Concrete Structures - 13481

    SciTech Connect

    Brown, K.G.; Kosson, D.S.; Garrabrants, A.C.; Sarkar, S.; Flach, G.; Langton, C.; Smith, F.G.III; Burns, H.; Van der Sloot, H.; Meeussen, J.C.L.; Seignette, P.F.A.B.; Samson, E.; Mallick, P.; Suttora, L.; Esh, D.; Fuhrmann, M.; Philip, J.

    2013-07-01

    The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the U.S. Department of Energy Office of Tank Waste Management. The CBP project has developed a set of integrated modeling tools and leaching test methods to help improve understanding and prediction of the long-term hydraulic and chemical performance of cementitious materials used in nuclear applications. State-of-the-art modeling tools, including LeachXS{sup TM}/ORCHESTRA and STADIUM{sup R}, were selected for their demonstrated abilities to simulate reactive transport and degradation in cementitious materials. The new U.S. Environmental Protection Agency leaching test methods based on the Leaching Environmental Assessment Framework (LEAF), now adopted as part of the SW-846 RCRA methods, have been used to help make the link between modeling and experiment. Although each of the CBP tools has demonstrated utility as a standalone product, coupling the models over relevant spatial and temporal solution domains can provide more accurate predictions of cementitious materials behavior over relevant periods of performance. The LeachXS{sup TM}/ORCHESTRA and STADIUM{sup R} models were first linked to the GoldSim Monte Carlo simulator to better and more easily characterize model uncertainties and as a means to coupling the models allowing linking to broader performance assessment evaluations that use CBP results for a source term. Two important degradation scenarios were selected for initial demonstration: sulfate ingress / attack and carbonation of cementitious materials. When sufficient sulfate is present in the pore solution external to a concrete barrier, sulfate can diffuse into the concrete, react with the concrete solid phases, and cause cracking that significantly changes the transport and structural properties of the concrete. The penetration of gaseous carbon dioxide within partially saturated concrete usually initiates a series of carbonation

  2. SOLID WASTE OPTIONS FOR MUNICIPAL PLANNERS - VERSION 3.1 - A SOFTWARE TOOL FOR PRELIMINARY PLANNING - USER DOCUMENTATION

    EPA Science Inventory

    Municipalities face many challenges in managing nonhazardous solid waste. For instance, landfills are reaching capacity throughout the country, tipping fees are increasing, and regulations affecting the disposal and recycling of municipal solid waste (MSW) are being promulgated ...

  3. LONG-TERM TECHNETIUM INTERACTIONS WITH REDUCING CEMENTITIOUS MATERIALS

    SciTech Connect

    Kaplan, D.; Lilley, M.; Almond, P.; Powell, B.

    2011-03-15

    Technetium is among the key risk drivers at the Saltstone Facility. The way that it is immobilized in this cementitious waste form is by converting its highly mobile Tc(VII) form to a much less mobile Tc(IV) form through reduction by the cement's blast furnace slag. This report includes a review of published data and experimental results dealing with Tc leaching from Portland cement waste forms. The objectives for the literature study were to document previous reports of Tc interactions with slag-containing cementitious materials. The objectives for the laboratory study were to measure Tc-saltstone Kd values under reducing conditions. From the literature it was concluded: (1) Spectroscopic evidence showed that when Tc(IV) in a slag-cement was exposed to an oxidizing environment, it will convert to the more mobile Tc(VII) species within a short time frame, 2.5 years. (2) SRS saltstone will reduce Tc(VII) in the absence of NaS or sodium dithionite in a reducing atmosphere. (3) Only trace concentrations of atmospheric oxygen (30 to 60 ppm O{sub 2}; Eh 120 mV) at the high pH levels of cementitious systems is required to maintain Tc as Tc(VII). (4) Experimental conditions must be responsible for wide variability of measured K{sub d} values, such that they are either very low, {approx}1 mL/g, or they are very high {approx}1000 mL/g, suggesting that Tc(VII) or Tc(IV) dominate the systems. Much of this variability appears to be the result of experimental conditions, especially direct controls of oxygen contact with the sample. (5) A field study conducted at SRS in the 1980s indicated that a slag-saltstone immobilized Tc for 2.5 years. Below background concentrations of Tc leached out of the slag-containing saltstone, whereas Tc leached out of the slag-free saltstone at the rate of nitrate loss. One possible explanation for the immobilization of Tc in this study was that the slag-saltstone maintained reducing conditions within the core of the 55-gallon sample, whereas in

  4. Thermal conductivity and other properties of cementitious grouts

    SciTech Connect

    Allan, M.

    1998-08-01

    The thermal conductivity and other properties cementitious grouts have been investigated in order to determine suitability of these materials for grouting vertical boreholes used with geothermal heat pumps. The roles of mix variables such as water/cement ratio, sand/cement ratio and superplasticizer dosage were measured. In addition to thermal conductivity, the cementitious grouts were also tested for bleeding, permeability, bond to HDPE pipe, shrinkage, coefficient of thermal expansion, exotherm, durability and environmental impact. This paper summarizes the results for selected grout mixes. Relatively high thermal conductivities were obtained and this leads to reduction in predicted bore length and installation costs. Improvements in shrinkage resistance and bonding were achieved.

  5. THERMAL CONDUCTIVITY AND OTHER PROPERTIES OF CEMENTITIOUS GROUTS

    SciTech Connect

    ALLAN,M.

    1998-05-01

    The thermal conductivity and other properties cementitious grouts have been investigated in order to determine suitability of these materials for grouting vertical boreholes used with geothermal heat pumps. The roles of mix variables such as water/cement ratio, sand/cement ratio and superplasticizer dosage were measured. In addition to thermal conductivity, the cementitious grouts were also tested for bleeding, permeability, bond to HDPE pipe, shrinkage, coefficient of thermal expansion, exotherm, durability and environmental impact. This paper summarizes the results for selected grout mixes. Relatively high thermal conductivities were obtained and this leads to reduction in predicted bore length and installation costs. Improvements in shrinkage resistance and bonding were achieved.

  6. Phosphate Ions - Does Exposure Lead to Degradation of Cementitious Materials?

    SciTech Connect

    Naus, Dan J; Mattus, Catherine H; Dole, Leslie Robert

    2008-01-01

    An assessment of the potential effects of phosphate ions on cementitious materials was made through a review of the literature, contacts with concrete research personnel, and conduct of a "bench-scale" laboratory investigation. Results indicate that no harmful interactions occur between phosphate ions and cememtitious materials unless phosphates are present in form of phosphoric acid.

  7. Method for the production of cementitious compositions and aggregate derivatives from said compositions, and cementitious compositions and aggregates produced thereby

    DOEpatents

    Minnick, L. John

    1983-01-01

    The present invention relates to a method for preparing synthetic shaped cementitious compositions having high quality even without the addition of high energy binders, such as portland cement, through the use of the spent residue from a fluidized combustion bed of the type wherein limestone particles are suspended in a fluidized medium and sulfur oxides are captured, and pulverized coal fly ash.

  8. Report: treatment of commercial, construction and demolition waste in North Rhine-Westphalia: policy-making and operation options.

    PubMed

    Karavezyris, Vassilios

    2007-04-01

    This paper summarizes a long-term-investigation of the mechanical treatment of commercial, construction and demolition waste materials in North Rhine-Westphalia in the light of applied operation standards and a disposal ban on untreated waste. It is shown how both the allocation of output materials from mechanical treatment plants and the subsequent treatment channels have changed since enforcement of the ban in 2005. Based on the findings of the investigation, two waste management scenarios offering alternative policies have been defined and are discussed. It is suggested that consistent enforcement of the ban affects both the diversion of waste to incineration and the recovery of materials on a regional scale. On the other hand, potential energy recovery may be fully exploited only insofar as operators of mechanical treatment plants concentrate their business on the production of refuse-derived fuel. PMID:17439054

  9. PARTNERSHIP FOR THE DEVELOPMENT OF NEXT GENERATION SIMULATION TOOLS TO EVALUATE CEMENTITIOUS BARRIERS AND MATERIALS USED IN NUCLEAR APPLICATION - 8388

    SciTech Connect

    Langton, C; Richard Dimenna, R

    2008-01-29

    The US DOE has initiated a multidisciplinary cross cutting project to develop a reasonable and credible set of tools to predict the structural, hydraulic and chemical performance of cement barriers used in nuclear applications over extended time frames (e.g., > 100 years for operating facilities and > 1000 years for waste management). A partnership that combines DOE, NRC, academia, private sector, and international expertise has been formed to accomplish the project objectives by integrating existing information and realizing advancements where necessary. The set of simulation tools and data developed under this project will be used to evaluate and predict the behavior of cementitious barriers used in near surface engineered waste disposal systems, e.g., waste forms, containment structures, entombments and environmental remediation, including decontamination and decommissioning (D&D) activities. The simulation tools will also support analysis of structural concrete components of nuclear facilities (spent fuel pools, dry spent fuel storage units, and recycling facilities, e.g., fuel fabrication, separations processes). Simulation parameters will be obtained from prior literature and will be experimentally measured under this project, as necessary, to demonstrate application of the simulation tools for three prototype applications (waste form in concrete vault, high level waste tank grouting, and spent fuel pool). Test methods and data needs to support use of the simulation tools for future applications will be defined. This is a national issue that affects all waste disposal sites that use cementitious waste forms and structures, decontamination and decommissioning activities, service life determination of existing structures, and design of future public and private nuclear facilities. The problem is difficult because it requires projecting conditions and responses over extremely long times. Current performance assessment analyses show that engineered barriers are

  10. Capturing the Invisible Resource. Analysis of Waste Heat Potential in Chinese Industry and Policy Options for Waste Heat to Power Generation

    SciTech Connect

    Lu, Hongyou

    2015-05-01

    This study analyzed the theoretical maximum potential and practical potential of waste heat in the cement, iron, and steel, and glass sectors in China, based on thermal energy modeling, expert interviews, and literature reviews.

  11. Tensile strength of cementitious materials under triaxial loading

    NASA Astrophysics Data System (ADS)

    Tsubota, Shuji

    1998-11-01

    A general tension-compression-compression (sigmasb1, sigmasb2=sigmasb3) failure criterion for brittle materials is mathematically developed using FEM analysis and experimentally verified by use of the cementitious composite axial tensile test (CCATT). This tensile failure criterion is based on the stress concentration derived from the classical theory of elasticity. This analytical approach shows the upper bound of the tension-compression-compression failure surface for brittle materials. Since the CCATT applies confining hydraulic pressure, a tensile specimen is subjected to triaxial loading defined by the principal stress ratio sigmasb1/|sigmasb2|. When lateral pressure increases, tensile strength decreases; therefore, stress concentration is defined as a function of the principal stress ratio. The model has three distinct regions of behavior corresponding to the principal stress ratio, 0≤sigmasb1/|sigmasb2|<0.9 (high-lateral pressure), 0.9≤sigmasb1/|sigmasb2|<3.0 (medium-lateral pressure), 3.0≤sigmasb1/|sigmasb2| (low-lateral pressure). The experimental failure line shows true tensile strength of cementitious materials under low-lateral pressure. The predicted nominal stress fsb{ta} with large size specimens for the CCATT is written as$fsb{ta}=gamma*{1/{Kt}}*alpha* pwhere gamma$ is the size effect obtained by experimental results; Kt is the stress concentration factor derived from triaxial loading. Tensile strength values from the CCATT are compared to experimental results from other tests such as the uniaxial tensile test and the split cylinder test. CCATT results are analyzed using Weibull theory to measure material reliability and to develop characteristic stresses for construction design. Failure analysis using fractography was conducted on fractured cementitious materials and composites. The failure analysis on test specimens correlated well with FEM stress distributions and with the principal stress ratio. The observed fracture behavior (fracture

  12. Long-term assessment of waste management options--a new, integrated and goal-oriented approach.

    PubMed

    Döberl, G; Huber, R; Brunner, P H; Eder, M; Pierrard, R; Schönbäck, W; Frühwirth, W; Hutterer, H

    2002-08-01

    Selected waste management scenarios were evaluated with regard to the goals of the Austrian Waste Management Act, taking into account long-term environmental protection and resource conservation as well as costs. Municipal solid waste (MSW) and sewage sludge have been chosen as the system inputs. The scenarios were compared to the status-quo scenario by combining Material Flow Analysis (MFA) and economic evaluation methods. Both, welfare-oriented Cost-Benefit Analysis (CBA) and Modified Cost-Effectiveness Analysis (MCEA) were applied for this assessment. Unlike CBA, MCEA takes into consideration long-term impacts of landfilled material in non-monetary terms. The results of the CBA correspond to those of the MCEA. Both evaluation methods confirm: If long-term effects are taken into account with the same weight irrespective of when they occur, the Austrian goals of waste management are reached more efficiently by thermal waste treatment scenarios than by mechanical-biological treatment scenarios or by landfilling without pre-treatment. PMID:12363091

  13. Defense Waste Processing Facility: Report of task force on options to mitigate the effect of nitrite on DWPF operations

    SciTech Connect

    Randall, D.; Marek, J.C.

    1992-03-01

    The possibility of accumulating ammonium nitrate (an explosive) as well as organic compounds in the DWPF Chemical Processing Cell Vent System was recently discovered. A task force was therefore organized to examine ways to avoid this potential hazard. Of thirty-two processing/engineering options screened, the task force recommended five options, deemed to have the highest technical certainty, for detailed development and evaluation: Radiolysis of nitrite in the tetraphenylborate precipitate slurry feed in a new corrosion-resistant facility. Construction of a Late Washing Facility for precipitate washing before transfer to the DWPF; Just-in-Time'' precipitation; Startup Workaround by radiolysis of nitrite in the existing corrosion-resistant Pump Pit tanks; Ammonia venting and organics separation in the DWPF; and, Estimated costs and schedules are included in this report.

  14. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A PRINTING PLATE PREPARATION SECTION OF A NEWSPAPER.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of th...

  15. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF ROOM AIR CONDITIONING UNITS AND HUMIDIFIERS.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE), to assist in conducting waste minimization assessments at thirty small to medium sized businesses in the state of New Jersey. One of th...

  16. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF FINE CHEMICALS USING BATCH PROCESSES.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small to medium sized businesses in the state of New Jersey. One of the...

  17. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF PAINTS PRIMARILY FOR METAL FINISHING.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of th...

  18. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF PLASTIC CONTAINERS BY INJECTION MOLDING

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  19. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR AN ELECTRICAL UTILITY TRANSMISSION SYSTEM MONITORING AND MAINTENANCE FACILITY

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  20. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTI- VITIES AND OPTIONS FOR A FABRICATOR AND FINISHER OF STEEL COMPUTER CABINETS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of th...

  1. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A FOSSIL FUEL-FIRED ELECTRICAL GENERATING STATION.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of the...

  2. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A FABRICATOR AND FINISHER OF STEEL COMPUTER CABINETS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  3. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF ROOM AIR CONDITIONING UNITS AND HUMIDIFIERS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) ,to assist in conducting waste minimization assessments at- thirty small- to medium-sized businesses in the state of New Jersey. ne of th...

  4. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A LOCAL BOARD OF EDUCATION IN NEW JERSEY

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at 30 small- to medium-sized businesses in the state of New Jersey. ne of the site...

  5. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF WIRE STOCK USED FOR PRODUCTION OF METAL ITEMS.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of th...

  6. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF FIRE RETARDANT PLASTIC PELLETS AND HOT MELT ADHESIVES.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small to medium sized businesses in the state of New Jersey. One of the...

  7. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF WIRE STOCK USED FOR PRODUCTION OF METAL ITEMS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  8. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF PLASTIC CONTAINERS BY INJECTION MOLDING.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  9. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A MANUFACTURER OF GENERAL PURPOSE PAINTS AND PAINTING SUPPLIES

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  10. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR AN ELECTRICAL UTILITY TRANSMISSION SYSTEM MONITORING AND MAINTENANCE FACILITY.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  11. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A LOCAL BOARD OF EDUCATION IN NEW JERSEY.

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at 30 small- to medium-sized businesses in the state of New Jersey. One of the si...

  12. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTIVITIES AND OPTIONS FOR A FOSSIL FUEL-FIRED ELECTRICAL GENERATING STATION

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. ne of the ...

  13. ENVIRONMENTAL RESEARCH BRIEF: WASTE REDUCTION ACTI- VITIES AND OPTIONS FOR A MANUFACTURER OF GENERAL PURPOSE PAINTS AND PAINTING SUPPLIES

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) funded a project with the New Jersey Department of Environmental Protection and Energy (NJDEPE) to assist in conducting waste minimization assessments at thirty small- to medium-sized businesses in the state of New Jersey. One of th...

  14. Glass cullet as a new supplementary cementitious material (SCM)

    NASA Astrophysics Data System (ADS)

    Mirzahosseini, Mohammadreza

    Finely ground glass has the potential for pozzolanic reactivity and can serve as a supplementary cementitious material (SCM). Glass reaction kinetics depends on both temperature and glass composition. Uniform composition, amorphous nature, and high silica content of glass make ground glass an ideal material for studying the effects of glass type and particle size on reactivity at different temperature. This study focuses on how three narrow size ranges of clear and green glass cullet, 63--75 mum, 25--38 mum, and smaller than 25 mum, as well as combination of glass types and particle sizes affects the microstructure and performance properties of cementitious systems containing glass cullet as a SCM. Isothermal calorimetry, chemical shrinkage, thermogravimetric analysis (TGA), quantitative analysis of X-ray diffraction (XRD), and analysis of scanning electron microscope (SEM) images in backscattered (BS) mode were used to quantify the cement reaction kinetics and microstructure. Additionally, compressive strength and water sorptivity experiments were performed on mortar samples to correlate reactivity of cementitious materials containing glass to the performance of cementitious mixtures. A recently-developed modeling platform called "muic the model" was used to simulated pozzolanic reactivity of single type and fraction size and combined types and particle sizes of finely ground glass. Results showed that ground glass exhibits pozzolanic properties, especially when particles of clear and green glass below 25 mum and their combination were used at elevated temperatures, reflecting that glass cullet is a temperature-sensitive SCM. Moreover, glass composition was seen to have a large impact on reactivity. In this study, green glass showed higher reactivity than clear glass. Results also revealed that the simultaneous effect of sizes and types of glass cullet (surface area) on the degree of hydration of glass particles can be accounted for through a linear addition

  15. TECHNETIUM SORPTION BY CEMENTITIOUS MATERIALS UNDER REDUCING CONDITIONS

    SciTech Connect

    Kaplan, D.; Estes, S.; Arai, Y.; Powell, B.

    2012-01-31

    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% H2(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 data 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 6,362 mL/g (17% slag), for the TR547 Saltstone (45% slag) the conditional K{sub d} was 1258 mL/g, and for TR545 (90% slag) the conditional K{sub d} was 12,112 mL/g. It is anticipated that additional samples will be collected until steady state

  16. Nevada Transportatoion Options Study

    SciTech Connect

    P. GEHNER; E.M. WEAVER; L. FOSSUM

    2006-05-25

    This study performs a cost and schedule analysis of three Nevada Transportation options that support waste receipt at the repository. Based on the U.S. Department of Energy preference for rail transportation in Nevada (given in the Final Environmental Impact Statement), it has been assumed that a branch rail line would be constructed to support waste receipt at the repository. However, due to potential funding constraints, it is uncertain when rail will be available. The three Nevada Transportation options have been developed to meet a varying degree of requirements for transportation and to provide cost variations used in meeting the funding constraints given in the Technical Direction Letter guidelines for this study. The options include combinations of legal-weight truck, heavy-haul truck, and rail. Option 1 uses a branch rail line that would support initial waste receipt at the repository in 2010. Rail transportation would be the primary mode, supplemented by legal weight trucks. This option provides the highest level of confidence in cost and schedule, lowest public visibility, greatest public acceptability, lowest public dose, and is the recommended option for support of waste receipt. The completion of rail by 2010 will require spending approximately $800 million prior to 2010. Option 2 uses a phased rail approach to address a constrained funding scenario. To meet funding constraints, Option 2 uses a phased approach to delay high cost activities (final design and construction) until after initial waste receipt in 2010. By doing this, approximately 95 percent of the cost associated with completion of a branch rail line is deferred until after 2010. To support waste receipt until a branch rail line is constructed in Nevada, additional legal-weight truck shipments and heavy-haul truck shipments (on a limited basis for naval spent nuclear fuel) would be used to meet the same initial waste receipt rates as in Option 1. Use of heavy-haul shipments in the absence

  17. Application of DOE prescribed guides to the evaluation of Hanford`s Mixed Low Level Solid Waste Treatment Options

    SciTech Connect

    Campbell, B.F.; Nash, C.R.

    1994-10-01

    A recent Westinghouse Hanford Company report (WHC-SD-W100-ES-008, February, 1994), compared a Vitrification process to the WRAP-2A Grout/PE process for the treatment of Mixed Low Level Waste (MLLW). This comparison applied a limited scope numerical evaluation to compare technology complexity of the two processes, but focused primarily on capital and operating costs. The work reported here is supplementary to WHC-SD-Wl00-ES-008. It provides a record of the application of the more formal DOE-prescribed criteria (Treatment Selection Guides for Federal Facility Compliance Act Draft Site Treatment Plans) to the Vitrification and Grout/PE processes previously evaluated. Results of the evaluation favored the Grout/PE process by a weighted score of 83 to 78 over the Plasma arc vitrification process.

  18. Characterisation of medical-waste sterilisation-plant wastewater and a preliminary study of coagulation-flocculation treatment options.

    PubMed

    Ozkan, O; Mihçiokur, H; Azgin, S T; Ozdemir, O

    2010-01-01

    Wastewater from a medical-waste sterilisation plant (MWSP) contains unique pollutants and requires on-site treatment to prevent contamination of the municipal sewage system and receiving water bodies. Therefore, to meet the prescribed discharge standards and comply with the legal regulations, pre-treatment must be applied to MWSP wastewater. In this study, the capabilities of coagulation-flocculation processes were investigated for MWSP wastewater treatment. Processes using ferric chloride, ferrous sulfate and aluminium sulfate as coagulants were characterised. During the coagulation experiments, seven different coagulant dosages and four different pH values were evaluated to determine the optimum coagulant dosage and pH value. The highest removal efficiency of chemical oxygen demand (COD) was obtained using 300 mg/L of ferric chloride at pH 10. A COD removal of about 60% as well as considerable reductions in the amounts of suspended solids, nitrogen and phosphorus were realised. PMID:20651429

  19. CEMENTITIOUS BARRIERS PARTNERSHIP FY13 MID-YEAR REPORT

    SciTech Connect

    Burns, H.; Flach, G.; Langton, C.; KOSSON, D.; BROWN, K.; SAMSON, E.; MEEUSSEN, J.; SLOOT, H.; GARBOCZI, E.

    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. THAMES 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

  20. Development of a processing and treatment solution for a thoria waste stream

    SciTech Connect

    Anderson, Andy; Mitchell, Charles; Jenkins, Jon; Simmons, Richard

    2007-07-01

    Waste Management Technology Ltd (WMT) has developed the optimal process for immobilizing a solid waste contaminated with thorium dioxide (thoria). The physical and chemical characteristics of the waste present challenges to producing a wasteform acceptable for disposal. Also, high-energy radiation from thorium's decay progeny requires a treatment plant with shielding and remote handling facilities. Key points of the paper are as follows. 1. Treatment options were investigated and the best practicable means identified as intimate mixing of the waste with cementitious grout. 2. Samples were analysed for particle size and organic contamination. 3. Small-scale active mixes resulted in a single treatment formulation for all the waste. Leach tests confirmed that the organic material is adequately retained within the immobilised waste provided activated carbon is included in the formulation. 4. Active mixes at the two litre scale confirmed that the formulation is mixable and the product acceptable and consistent with expectations from the earlier work. 5. WMT is constructing a treatment plant at its Winfrith site, based on remote grouting in a 200 litre drum with a sacrificial mixer. Inactive full-scale trials with such 200 litre drums were carried out after selection of simulants with the appropriate physical properties. (authors)

  1. Modelling for the mechanical behavior of cementitious granular materials

    NASA Astrophysics Data System (ADS)

    Zhong, Xiaoxiong

    Crack damages due to load application are commonly observed in cementitious granular materials such as concrete, cemented sand, and ceramic materials. Previous analytical models for these types of materials have been developed based on continuum mechanics using a phenomenological approach. However, the theories of continuum mechanics have limitations when used for analyzing fracture mechanism and localized damages at a micro-scale level. Therefore, a microstructural approach is desirable for the analysis of these types of materials. In this dissertation, a contact law was derived for the inter-particle behavior of two particles connected by a cement binder. Microcracking process within binder was fully taken into account by regarding crack length as a basic damage factor. The binder initially contains small-size cracks which propagate and grow under external loading. As a result the binder is weakened with lower strength in shear and tension. Theory of fracture mechanics was employed to model the propagation and growth of these microcracks for both the shear fracture mode and normal fracture mode. The contact law was then incorporated in the analysis for the overall damage behaviors of cementitious granular material using the statistical micromechanics approach and the distinct element method. These overall damage behaviors include the stress-strain relationship, fracture strength, development of damage zone, and fatigue deformation. The micro-parameters affecting these behaviors are mainly the microcrack length and density, binder toughness, and binder elastic constants. In the numerical simulations, the cementitious granular materials were represented by 2-D random assemblies of rods bonded by cement binders with preexisting microcracks. Stress-strain relationships were modeled and validated for the uniaxial tension and compression tests, biaxial tension and compression tests, and double cantilever beam test. Force-deflection relationship and fatigue deformation

  2. Heavy ion beam measurement of the hydration of cementitious materials.

    PubMed

    Livingston, R A; Schweitzer, J S; Rolfs, C; Becker, H-W; Kubsky, S; Spillane, T; Zickefoose, J; Castellote, M; de Viedma, P G; Cheung, J

    2010-01-01

    The setting and development of strength of Portland cement concrete depends upon the reaction of water with various phases in the Portland cement. Nuclear resonance reaction analysis (NRRA) involving the (1)H((15)N,alpha,gamma)(12)C reaction has been applied to measure the hydrogen depth profile in the few 100 nm thick surface layer that controls the early stage of the reaction. Specific topics that have been investigated include the reactivity of individual cementitious phases and the effects of accelerators and retarders. PMID:19931465

  3. Technetium Sorption by Cementitious Materials Under Reducing Conditions

    SciTech Connect

    Kaplan, Daniel I.; Estes, Shanna L.; Powell, Brian A.

    2012-09-28

    The objective of this study was to measure technetium ({sup 99}Tc) sorption to cementitious materials under reducing conditions to simulate Saltstone Disposal Facility conditions. {sup 99}Tc(VII) batch sorption experiments were conducted for 319 days in an inert glovebag with a variety of cementitious materials (aged cement, Vault 2, TR545, and TR547) containing varying amounts of blast furnace slag. Between 154 and 319 days, the {sup 99}Tc aqueous concentrations tended to remain constant and samples amended with different initial {sup 99}Tc concentrations, tended to merge at about 10{sup -9} M for Vault 2 (17% slag) and TR545 (90% slag) and 10{sup -8} M for TR547 (45% slag). This data provided strong evidence that solubility, and not adsorption (K{sub d} values), was controlling aqueous {sup 99}Tc concentrations. Laboratory data superimposed over thermodynamic speciation diagrams further supported the conclusion that solubility, and not adsorption controlled {sup 99}Tc aqueous concentrations. The oxidation state of the aqueous {sup 99}Tc at the end of the sorption experiment was determined by solvent extraction to be almost entirely {sup 99}Tc(VII). The pH of the present system was ~11.8. Previously proposed solubility controlling phases including Tc-sulfides may be present, but do not appear to control solubility. After the 319 day sorption period, the suspensions were removed from the glovebag and a desorption step under oxic conditions was conducted for 20 days by adding oxic, pH-buffered solutions to the suspensions. {sup 99}Tc aqueous concentrations increased by more than an order of magnitude and Eh increased by several hundred millivolts within 24 hours after the introduction of the oxic solutions. These desorption results are consistent with re-oxidation and dissolution/desorption of {sup 99}Tc(IV) phases possibly present in the cementitious materials after the anoxic sorption step of the experiment. Aqueous {sup 99}Tc concentrations continued to increase

  4. Designing added functions in engineered cementitious composites

    NASA Astrophysics Data System (ADS)

    Yang, En-Hua

    In this dissertation, a new and systematic material design approach is developed for ECC with added functions through material microstructures linkage to composite macroscopic behavior. The thesis research embodies theoretical development by building on previous ECC micromechanical models, and experimental investigations into three specific new versions of ECC with added functions aimed at addressing societal demands of our built infrastructure. Specifically, the theoretical study includes three important ECC modeling elements: Steady-state crack propagation analyses and simulation, predictive accuracy of the fiber bridging constitutive model, and development of the rate-dependent strain-hardening criteria. The first element establishes the steady-state cracking criterion as a fundamental requirement for multiple cracking behavior in brittle matrix composites. The second element improves the accuracy of crack-width prediction in ECC. The third element establishes the micromechanics basis for impact-resistant ECC design. Three new ECCs with added functions were developed and experimentally verified in this thesis research through the enhanced theoretical framework. A green ECC incorporating a large volume of industrial waste was demonstrated to possess reduced crack width and drying shrinkage. The self-healing ECC designed with tight crack width was demonstrated to recover transport and mechanical properties after microcrack damage when exposed to wet and dry cycles. The impact-resistant ECC was demonstrated to retain tensile ductility with increased strength under moderately high strain-rate loading. These new versions of ECC with added functions are expected to contribute greatly to enhancing the sustainability, durability, and safety of civil infrastructure built with ECC. This research establishes the effectiveness of micromechanics-based design and material ingredient tailoring for ECC with added new attributes but without losing its basic tensile ductile

  5. Rehabilitation Options

    MedlinePlus

    ... Speech Pathology Occupational Therapy Art Therapy Recreational therapy Neuropsychology Home Care Options Advanced Care Planning Palliative Care ... Speech Pathology Occupational Therapy Art Therapy Recreational therapy Neuropsychology Home Care Options Advanced Care Planning Palliative Care ...

  6. Pricing Options.

    ERIC Educational Resources Information Center

    Tenopir, Carol

    1998-01-01

    Presents results of a recent survey of over 100 public and academic libraries about pricing options from online companies. Most options fall into three categories: pay-as-you-go, fixed-rate, and user-based. Results are discussed separately for public and academic libraries and for consortial discounts. Trends in pricing options preferred by…

  7. Semiautomatic classification of cementitious materials using scanning electron microscope images

    NASA Astrophysics Data System (ADS)

    Drumetz, Lucas; Mura, Mauro Dalla; Meulenyzer, Samuel; Lombard, Sébastien; Chanussot, Jocelyn

    2015-11-01

    Segmentation and classification are prolific research topics in the image processing community. These topics have been increasingly used in the context of analysis of cementitious materials on images acquired with a scanning electron microscope. Indeed, there is a need to be able to detect and to quantify the materials present in a cement paste in order to follow the chemical reactions occurring in the material even days after the solidification. We propose a new approach for segmentation and classification of cementitious materials based on the denoising of the data with a block-matching three-dimensional (3-D) algorithm, binary partition tree (BPT) segmentation, support vector machines (SVM) classification, and interactivity with the user. The BPT provides a hierarchical representation of the spatial regions of the data, allowing a segmentation to be selected among the admissible partitions of the image. SVMs are used to obtain a classification map of the image. This approach combines state-of-the-art image processing tools with user interactivity to allow a better segmentation to be performed, or to help the classifier discriminate the classes better. We show that the proposed approach outperforms a previous method when applied to synthetic data and several real datasets coming from cement samples, both qualitatively with visual examination and quantitatively with the comparison of experimental results with theoretical ones.

  8. Technetium Sorption By Cementitious Materials Under Reducing Conditions

    SciTech Connect

    Kaplan, Daniel I.; Estes, Shanna L.; Arai, Yuji; Powell, Brian A.

    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 data 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

  9. Method for the production of cementitious compositions and aggregate derivatives from said compositions

    DOEpatents

    Minnick, L. John

    1981-01-01

    Method for the production of cementitious compositions and aggregate derivatives of said compositions, and cementitious compositions and aggregates produced by said method, wherein fluidized bed combustion residue and pozzolanic material, such as pulverized coal combustion system fly ash, are incorporated in a cementitious mix. The mix is cast into desired shape and cured. If desired, the shape may then be crushed so as to result in a fluidized bed combustion residue-fly ash aggregate material or the shape may be used by itself.

  10. Method of preparing nuclear wastes for tansportation and interim storage

    DOEpatents

    Bandyopadhyay, Gautam; Galvin, Thomas M.

    1984-01-01

    Nuclear waste is formed into a substantially water-insoluble solid for temporary storage and transportation by mixing the calcined waste with at least 10 weight percent powdered anhydrous sodium silicate to form a mixture and subjecting the mixture to a high humidity environment for a period of time sufficient to form cementitious bonds by chemical reaction. The method is suitable for preparing an interim waste form from dried high level radioactive wastes.

  11. Quantitative diffuse reflectance infrared fourier transform spectrometric studies of cementitious blends

    SciTech Connect

    Rebagay, T.V.; Dodd, D.A.

    1989-07-01

    The effective immobilization of low-level radioactive liquid wastes in the form of grout depends on the quality of the dry cementitious blends used in the grout formulation. Variation in the mix ratios of the components of the blend can cause detrimental effects on the processing behavior of the grout slurry and the final properties of the cured grout. Thus the blends require thorough chemical characterization and monitoring by strict quality control protocols. In an earlier work at our laboratories, Fourier transform infrared- transmission method has been successfully applied in the analysis of blends of cement, fly ash, and clays. However, this method involved time-consuming sample preparation resulting in slow turnaround for repetitive sampling. A practical approach to quality control required a fast and simple method for the analysis of the blends. This paper describes a diffuse reflectance infrared Fourier transform (DRIFT) spectrometric procedure for the routine examination of neat blends consisting of cement, fly ash, clays and/or blast furnace slags. (1 ref., 10 figs., 4 tabs.)

  12. Performance and mechanism on a high durable silica alumina based cementitious material composed of coal refuse and coal combustion byproducts

    NASA Astrophysics Data System (ADS)

    Yao, Yuan

    Coal refuse and combustion byproducts as industrial solid waste stockpiles have become great threats to the environment. Recycling is one practical solution to utilize this huge amount of solid waste through activation as substitute for ordinary Portland cement. The central goal of this dissertation is to investigate and develop a new silica-alumina based cementitious material largely using coal refuse as a constituent that will be ideal for durable construction, mine backfill, mine sealing and waste disposal stabilization applications. This new material is an environment-friendly alternative to ordinary Portland cement. The main constituents of the new material are coal refuse and other coal wastes including coal sludge and coal combustion products (CCPs). Compared with conventional cement production, successful development of this new technology could potentially save energy and reduce greenhouse gas emissions, recycle vast amount of coal wastes, and significantly reduce production cost. A systematic research has been conducted to seek for an optimal solution for enhancing pozzolanic reactivity of the relatively inert solid waste-coal refuse in order to improve the utilization efficiency and economy benefit for construction and building materials. The results show that thermal activation temperature ranging from 20°C to 950°C significantly increases the workability and pozzolanic property of the coal refuse. The optimal activation condition is between 700°C to 800°C within a period of 30 to 60 minutes. Microanalysis illustrates that the improved pozzolanic reactivity contributes to the generated amorphous materials from parts of inert aluminosilicate minerals by destroying the crystallize structure during the thermal activation. In the coal refuse, kaolinite begins to transfer into metakaol in at 550°C, the chlorite minerals disappear at 750°C, and muscovite 2M1 gradually dehydroxylates to muscovite HT. Furthermore, this research examines the environmental

  13. Innovative Structural Materials and Sections with Strain Hardening Cementitious Composites

    NASA Astrophysics Data System (ADS)

    Dey, Vikram

    The motivation of this work is based on development of new construction products with strain hardening cementitious composites (SHCC) geared towards sustainable residential applications. The proposed research has three main objectives: automation of existing manufacturing systems for SHCC laminates; multi-level characterization of mechanical properties of fiber, matrix, interface and composites phases using servo-hydraulic and digital image correlation techniques. Structural behavior of these systems were predicted using ductility based design procedures using classical laminate theory and structural mechanics. SHCC sections are made up of thin sections of matrix with Portland cement based binder and fine aggregates impregnating continuous one-dimensional fibers in individual or bundle form or two/three dimensional woven, bonded or knitted textiles. Traditional fiber reinforced concrete (FRC) use random dispersed chopped fibers in the matrix at a low volume fractions, typically 1-2% to avoid to avoid fiber agglomeration and balling. In conventional FRC, fracture localization occurs immediately after the first crack, resulting in only minor improvement in toughness and tensile strength. However in SHCC systems, distribution of cracking throughout the specimen is facilitated by the fiber bridging mechanism. Influence of material properties of yarn, composition, geometry and weave patterns of textile in the behavior of laminated SHCC skin composites were investigated. Contribution of the cementitious matrix in the early age and long-term performance of laminated composites was studied with supplementary cementitious materials such as fly ash, silica fume, and wollastonite. A closed form model with classical laminate theory and ply discount method, coupled with a damage evolution model was utilized to simulate the non-linear tensile response of these composite materials. A constitutive material model developed earlier in the group was utilized to characterize and

  14. Saccharification of Miscanthus x giganteus, incorporation of lignocellulosic by-product in cementitious matrix.

    PubMed

    Le Ngoc Huyen, Tran; Queneudec T'kint, Michèle; Remond, Caroline; Chabbert, Brigitte; Dheilly, Rose-Marie

    2011-11-01

    Given the non competition of miscanthus with food and animal feed, this lignocellulosic species has attracted attention as a possible biofuel resource. However, sustainability of ethanol production from lignocelluloses biomass would imply reduction in the consumption of chemicals and/or energetic means, but also valorization of the lignocellulosic by-product remaining from enzymatic saccharification. Introduction of these by-products into a cementitious matrix could be used in manufacturing a lightweight composite. Miscanthus biomass was submitted to chemical pretreatments followed by saccharification using an enzymatic cocktail. Residues from saccharification were then mixed with a cementitious matrix. Given their mechanical properties and a good adherence between cement and by-product, the hardened materials could be used. However, the delay in the beginning of setting time is too long, which prevents the direct use of by-product into cementitious matrix. Preliminary experiments using a setting accelerator in the cementitious matrix permitted significant reduction in the setting time delay. PMID:22078741

  15. Dynamic fracture behaviour in fibre-reinforced cementitious composites

    NASA Astrophysics Data System (ADS)

    Yu, Rena C.; Cifuentes, Héctor; Rivero, Ignacio; Ruiz, Gonzalo; Zhang, Xiaoxin

    2016-08-01

    The object of this work is to simulate the dynamic fracture propagation in fibre-reinforced cementitious composites, in particular, in steel fibre reinforced concrete (SFRC). Beams loaded in a three-point bend configuration through a drop-weight impact device are considered. A single cohesive crack is assumed to propagate at the middle section; the opening of this crack is governed by a rate-dependent cohesive law; the fibres around the fracture plane are explicitly represented through truss elements. The fibre pull-out behaviour is depicted by an equivalent constitutive law, which is obtained from an analytical load-slip curve. The obtained load-displacement curves and crack propagation velocities are compared with their experimental counterparts. The good agreement with experimental data testifies to the feasibility of the proposed methodology and paves the way to its application in a multi-scale framework.

  16. Retrieval options study

    SciTech Connect

    Not Available

    1980-03-01

    This Retrieval Options Study is part of the systems analysis activities of the Office of Nuclear Waste Isolation to develop the scientific and technological bases for radioactive waste repositories in various geologic media. The study considers two waste forms, high level waste and spent fuel, and defines various classes of waste retrieval and recovery. A methodology and data base are developed which allow the relative evaluation of retrieval and recovery costs and the following technical criteria: safety; technical feasibility; ease of retrieval; probable intact retrieval time; safeguards; monitoring; criticality; and licensability. A total of 505 repository options are defined and the cost and technical criteria evaluated utilizing a combination of facts and engineering judgments. The repositories evaluated are selected combinations of the following parameters: Geologic Media (salt, granite, basalt, shale); Retrieval Time after Emplacement (5 and 25 years); Emplacement Design (nominal hole, large hole, carbon steel canister, corrosion resistant canister, backfill in hole, nominal sleeves, thick wall sleeves); Emplacement Configuration (single vertical, multiple vertical, single horizontal, multiple horizontal, vaults; Thermal Considerations; (normal design, reduced density, once-through ventilation, recirculated ventilation); Room Backfill; (none, run-of-mine, early, 5 year delay, 25 year delay, decommissioned); and Rate of Retrieval; (same as emplacement, variably slower depending on repository/canister condition).

  17. Treatment studies of paint stripping waste from plastic media blasting

    SciTech Connect

    Spence, R.D.

    1995-12-31

    Blasting with plastic media is used to strip paint and decontaminate surfaces. For disposal the plastic media is pulverized into a plastic dust. About 10 wt % of the waste from plastic media blasting is pulverized paint, which makes the waste a characteristically hazardous waste because of the presence of barium, cadmium, chromium and lead in the paint pigments. Four separate treatments of this hazardous waste were studied: (1) density separation to remove the paint, (2) self-encapsulation of the mix of plastic and paint dust into plastic pellets, (3) solidification/stabilization (S/S) into cementitious waste forms, and (4) low-temperature ashing to destroy the large mass of nonhazardous polymer. Two types of plast blasting wastes were studied: a urea formaldehyde thermoset polymer and an acrylic thermoplastic polymer (polymethylmethacrylate). Toxicity Characteristic Leach Procedure (TCLP) extraction concentrations for the treated and untreated wastes are listed. Density separation failed to adequately separate the paint with an aqueous carbonate solution. Self-encapsulation reduced the waste volume by about 50%, but did not meet TCLP criteria. Cementitious solidification gave the lowest TCLP concentrations, but increased the waste volume by about 50%. Low-temperature ashing at 600 C resulted in a mass decrease of 93 to 98% for the wastes; the metals remaining in the ash could be stabilized with cementitious solidification and still result in a volume decrease of 75 to 95 volume percent.

  18. Options Study - Phase II

    SciTech Connect

    R. Wigeland; T. Taiwo; M. Todosow; W. Halsey; J. Gehin

    2010-09-01

    The Options Study has been conducted for the purpose of evaluating the potential of alternative integrated nuclear fuel cycle options to favorably address the issues associated with a continuing or expanding use of nuclear power in the United States. The study produced information that can be used to inform decisions identifying potential directions for research and development on such fuel cycle options. An integrated nuclear fuel cycle option is defined in this study as including all aspects of the entire nuclear fuel cycle, from obtaining natural resources for fuel to the ultimate disposal of used nuclear fuel (UNF) or radioactive wastes. Issues such as nuclear waste management, especially the increasing inventory of used nuclear fuel, the current uncertainty about used fuel disposal, and the risk of nuclear weapons proliferation have contributed to the reluctance to expand the use of nuclear power, even though it is recognized that nuclear power is a safe and reliable method of producing electricity. In this Options Study, current, evolutionary, and revolutionary nuclear energy options were all considered, including the use of uranium and thorium, and both once-through and recycle approaches. Available information has been collected and reviewed in order to evaluate the ability of an option to clearly address the challenges associated with the current implementation and potential expansion of commercial nuclear power in the United States. This Options Study is a comprehensive consideration and review of fuel cycle and technology options, including those for disposal, and is not constrained by any limitations that may be imposed by economics, technical maturity, past policy, or speculated future conditions. This Phase II report is intended to be used in conjunction with the Phase I report, and much information in that report is not repeated here, although some information has been updated to reflect recent developments. The focus in this Options Study was to

  19. Design Evolution Study - Aging Options

    SciTech Connect

    P. McDaniel

    2002-04-05

    The purpose of this study is to identify options and issues for aging commercial spent nuclear fuel received for disposal at the Yucca Mountain Mined Geologic Repository. Some early shipments of commercial spent nuclear fuel to the repository may be received with high-heat-output (younger) fuel assemblies that will need to be managed to meet thermal goals for emplacement. The capability to age as much as 40,000 metric tons of heavy metal of commercial spent nuclear he1 would provide more flexibility in the design to manage this younger fuel and to decouple waste receipt and waste emplacement. The following potential aging location options are evaluated: (1) Surface aging at four locations near the North Portal; (2) Subsurface aging in the permanent emplacement drifts; and (3) Subsurface aging in a new subsurface area. The following aging container options are evaluated: (1) Complete Waste Package; (2) Stainless Steel inner liner of the waste package; (3) Dual Purpose Canisters; (4) Multi-Purpose Canisters; and (5) New disposable canister for uncanistered commercial spent nuclear fuel. Each option is compared to a ''Base Case,'' which is the expected normal waste packaging process without aging. A Value Engineering approach is used to score each option against nine technical criteria and rank the options. Open issues with each of the options and suggested future actions are also presented. Costs for aging containers and aging locations are evaluated separately. Capital costs are developed for direct costs and distributable field costs. To the extent practical, unit costs are presented. Indirect costs, operating costs, and total system life cycle costs will be evaluated outside of this study. Three recommendations for aging commercial spent nuclear fuel--subsurface, surface, and combined surface and subsurface are presented for further review in the overall design re-evaluation effort. Options that were evaluated but not recommended are: subsurface aging in a new

  20. Nanomodification of Cementitious Materials: Fresh State and Early Age

    NASA Astrophysics Data System (ADS)

    Kawashima, Shiho

    Concrete is heterogeneous at all length scales and its microstructure evolves continuously over decades. Through the use of nanoparticles, it is possible to alter the microstructure of cementitious materials from within the first microsecond to control its rheological and eventual mechanical properties. The continued development of this technology hinges on adopting a materials science approach to achieve proper processing and measurement techniques, both of which are investigated in this study. Novel rheological methods are implemented to evaluate the fresh-state properties of cement pastes modified with nano-sized attapulgite clays. Previous studies have demonstrated that clays can reduce the lateral pressure exerted on formwork by self-consolidating concrete (SCC). It is hypothesized that this is tied to the influence of clays on two rheological properties of SCC: material cohesion and structural rebuilding. Therefore the effect of clays on adhesive properties is measured by the tack test and rate of rebuilding is evaluated by measuring relaxation time during creep. In addition, due to the complexity of cement rheology, i.e. simultaneous thixotropic rebuilding and hydration, the results are supplemented with a measure of the viscoelastic properties obtained through oscillatory shear rheometry. It is found that clays significantly increase cohesion and accelerate structural recovery of cement pastes. The results also indicate that the tack test is a suitable method for measuring the adhesive properties and structural evolution of cementitious materials in the fresh state. The potential of calcium carbonate (CaCO3) nanoparticles in improving the early-age properties of fly ash-cement pastes is investigated. The focus is on dispersing the CaCO3 nanoparticles to enhance their effect and limit the addition level necessary. The selected approach involves sonication in an aqueous medium and use of surfactant. Degree of dispersion and stability are quantitatively

  1. Solubility constraints affecting the migration of selenium through the cementitious backfill of a geological disposal facility.

    PubMed

    Felipe-Sotelo, M; Hinchliff, J; Evans, N D M; Read, D

    2016-03-15

    This work presents the study of the solubility of selenium under cementitious conditions and its diffusion, as SeO3(2-), through monolithic cement samples. The solubility studies were carried out under alkaline conditions similar to those anticipated in the near-field of a cement-based repository for low- and intermediate-level radioactive waste. Experiments were conducted in NaOH solution, 95%-saturated Ca(OH)2, water equilibrated with a potential backfill material (Nirex reference vault backfill, NRVB) and in solutions containing cellulose degradation products, with and without reducing agents. The highest selenium concentrations were found in NaOH solution. In the calcium-containing solutions, analysis of the precipitates suggests that the solubility controlling phase is Ca2SeO3(OH)2·2H2O, which appears as euhedral rhombic crystals. The presence of cellulose degradation products caused an increase in selenium concentration, possibly due to competitive complexation, thereby, limiting the amount of calcium available for precipitation. Iron coupons had a minor effect on selenium solubility in contrast to Na2S2O4, suggesting that effective reduction of Se(IV) occurs only at Eh values below -300mV. Radial through-diffusion experiments on NRVB and in a fly ash cement showed no evidence of selenium breakthrough after one year. However, autoradiography of the exposed surfaces indicated that some migration had occurred and that selenium was more mobile in the higher porosity backfill than in the fly ash cement. PMID:26642443

  2. Nano-modification to improve the ductility of cementitious composites

    SciTech Connect

    Yeşilmen, Seda; Al-Najjar, Yazin; Balav, Mohammad Hatam; Şahmaran, Mustafa; Yıldırım, Gürkan; Lachemi, Mohamed

    2015-10-15

    Effect of nano-sized mineral additions on ductility of engineered cementitious composites (ECC) containing high volumes of fly ash was investigated at different hydration degrees. Various properties of ECC mixtures with different mineral additions were compared in terms of microstructural properties of matrix, fiber-matrix interface, and fiber surface to assess improvements in ductility. Microstructural characterization was made by measuring pore size distributions through mercury intrusion porosimetry (MIP). Hydration characteristics were assessed using thermogravimetric analysis/differential thermal analysis (TGA/DTA), and fiber-matrix interface and fiber surface characteristics were assessed using scanning electron microscopy (SEM) through a period of 90 days. Moreover, compressive and flexural strength developments were monitored for the same period. Test results confirmed that mineral additions could significantly improve both flexural strength and ductility of ECC, especially at early ages. Cheaper Nano-CaCO{sub 3} was more effective compared to nano-silica. However, the crystal structure of CaCO{sub 3} played a very important role in the range of expected improvements.

  3. Bioreceptivity evaluation of cementitious materials designed to stimulate biological growth.

    PubMed

    Manso, Sandra; De Muynck, Willem; Segura, Ignacio; Aguado, Antonio; Steppe, Kathy; Boon, Nico; De Belie, Nele

    2014-05-15

    Ordinary Portland cement (OPC), the most used binder in construction, presents some disadvantages in terms of pollution (CO2 emissions) and visual impact. For this reason, green roofs and façades have gain considerable attention in the last decade as a way to integrate nature in cities. These systems, however, suffer from high initial and maintenance costs. An alternative strategy to obtain green facades is the direct natural colonisation of the cementitious construction materials constituting the wall, a phenomenon governed by the bioreceptivity of such material. This work aims at assessing the suitability of magnesium phosphate cement (MPC) materials to allow a rapid natural colonisation taking carbonated OPC samples as a reference material. For that, the aggregate size, the w/c ratio and the amount of cement paste of mortars made of both binders were modified. The assessment of the different bioreceptivities was conducted by means of an accelerated algal fouling test. MPC samples exhibited a faster fouling compared to OPC samples, which could be mainly attributed to the lower pH of the MPC binder. In addition to the binder, the fouling rate was governed by the roughness and the porosity of the material. MPC mortar with moderate porosity and roughness appears to be the most feasible material to be used for the development of green concrete walls. PMID:24602907

  4. Triboluminesence multifunctional cementitious composites with in situ damage sensing capability

    NASA Astrophysics Data System (ADS)

    Olawale, David O.; Dickens, Tarik; Uddin, Mohammed J.; Okoli, Okenwa O.

    2012-04-01

    Structural health monitoring of civil infrastructure systems like concrete bridges and dams has become critical because of the aging and overloading of these CIS. Most of the available SHM methods are not in-situ and can be very expensive. The triboluminescence multifunctional cementitious composites (TMCC) have in-built crack detection mechanism that can enable bridge engineers to monitor and detect abnormal crack formation in concrete structures so that timely corrective action can be taken to prevent costly or catastrophic failures. This article reports the fabrication process and test result of the flexural characterization of the TMCC. Accelerated durability test indicated that the 0.5 ZnS:Mn/Epoxy weight fraction ITOF sensor configuration to be more desirable in terms of durability. The alkaline environment at the highest temperature investigated (45 °C) resulted in significant reduction in the mean glass transition and storage moduli of the tested ITOF thin films. Further work is ongoing to correlate the TL response of the TMCC with damage, particularly crack opening.

  5. Reaction and Diffusion of Cementitious Water in Bentonite: Results of `Blind' Modelling

    NASA Astrophysics Data System (ADS)

    Watson, C.; Hane, K.; Savage, D.; Benbow, S.; Cuevas, J.; Fernandez, R.

    2009-04-01

    The potential deleterious geochemical interactions of clay with cement/concrete may provide a constraint on the use of the latter material in deep geological disposal facilities for radioactive wastes. Consequently, it is important to have a fundamental understanding of these interactions to be able to assess their likely impact over the long timescales appropriate to the isolation of radioactive wastes from the human environment. Here, a laboratory experiment investigating the effects of cementitious water diffusing through bentonite has been simulated using a coupled reactive-transport geochemical modelling code. The modelling study was carried out before the results of the experiments were available, as an exercise in ‘blind' modelling. A sensitivity study was carried out to investigate uncertainties associated with a number of input parameters, such as the precise nature of kinetic and ion-exchange reactions, diffusion coefficients, pore water composition, and montmorillonite dissolution models. The experiments used two types of fluid; one saturated with calcium hydroxide showed little mineralogical alteration, which was predicted by the computer simulations. A high pH K-Na-OH-based water however, caused alteration (pore blocking by hydrotalcite, gibbsite and brucite growth) to a depth of 2 mm in the bentonite after a period of 1 year. Experimental evidence showed that ion exchange of Mg-montmorillonite to K-montmorillonite was not confined to this thin region however, and was found to extend throughout the whole of the bentonite sample. The pore blocking by mineral precipitation and movement of ion exchange fronts through the bentonite were accurately simulated by the model. The choice of dissolution model for montmorillonite played an important role in the outcome of the simulations. Of the cases considered in the sensitivity study, that employing the so-called ‘Yamaguchi model' was clearly the best match, exhibiting all the main characteristics of the

  6. Technetium removal: preliminary flowsheet options

    SciTech Connect

    Eager, K.M.

    1995-10-24

    This document presents the results of a preliminary investigation into options for preliminary flowsheets for 99Tc removal from Hanford Site tank waste. A model is created to show the path of 99Tc through pretreatment to disposal. The Tank Waste Remediation (TWRS) flowsheet (Orme 1995) is used as a baseline. Ranges of important inputs to the model are developed, such as 99Tc inventory in the tanks and important splits through the TWRS flowsheet. Several technetium removal options are discussed along with sensitivities of the removal schemes to important model parameters

  7. Katimavik Options.

    ERIC Educational Resources Information Center

    Crelinsten, Michael; And Others

    Designed for students who are just about to complete Katimavik (a nine-month volunteer community service and experiential learning program for 17 to 21-year-old Canadian youth), the bilingual information guide presents facts and considerations about options in lifestyle, academic attainment, and career goals available as a result of Katimavik…

  8. Advanced Nuclear Fuel Cycle Options

    SciTech Connect

    Roald Wigeland; Temitope Taiwo; Michael Todosow; William Halsey; Jess Gehin

    2010-06-01

    A systematic evaluation has been conducted of the potential for advanced nuclear fuel cycle strategies and options to address the issues ascribed to the use of nuclear power. Issues included nuclear waste management, proliferation risk, safety, security, economics and affordability, and sustainability. The two basic strategies, once-through and recycle, and the range of possibilities within each strategy, are considered for all aspects of the fuel cycle including options for nuclear material irradiation, separations if needed, and disposal. Options range from incremental changes to today’s implementation to revolutionary concepts that would require the development of advanced nuclear technologies.

  9. Cementitious building material incorporating end-capped polyethylene glycol as a phase change material

    DOEpatents

    Salyer, Ival O.; Griffen, Charles W.

    1986-01-01

    A cementitious composition comprising a cementitious material and polyethylene glycol or end-capped polyethylene glycol as a phase change material, said polyethylene glycol and said end-capped polyethylene glycol having a molecular weight greater than about 400 and a heat of fusion greater than about 30 cal/g; the compositions are useful in making pre-formed building materials such as concrete blocks, brick, dry wall and the like or in making poured structures such as walls or floor pads; the glycols can be encapsulated to reduce their tendency to retard set.

  10. Method for characterization of the rate of movement of an oxidation front in cementitious materials

    DOEpatents

    Almond, Philip M.; Langton, Christine A.; Stefanko, David B.

    2016-03-01

    Disclosed are methods for determining the redox condition of cementitious materials. The methods are leaching methods that utilize a redox active transition metal indicator that is present in the cementitious material and exhibits variable solubility depending upon the oxidation state of the indicator. When the leaching process is carried out under anaerobic conditions, the presence or absence of the indicator in the leachate can be utilized to determine the redox condition of and location of the oxidation front in the material that has been subjected to the leaching process.

  11. Influence of electrified surface of cementitious materials on structure formation of hardened cement paste

    NASA Astrophysics Data System (ADS)

    Alekseev, A.; Gusakov, A.

    2015-01-01

    To provide high strength and durability of concrete it is necessary to study the influence of physical and chemical and mechanical principles of dispersed cementitious systems. The experimental bench was developed to study the influence of electrified surface of cementitious materials on structure formation of hardened cement paste. The test bench allows accelerating the processes of dissolution of cementing materials in water due to influence of electric discharge on their surface. Cement activation with high-voltage corona discharge when AC current is applied allows increasing the ultimate compressive strength of hardened cement paste by 46% at the age of one day and by 20% at the age of 28 days.

  12. Quantifying moisture transport in cementitious materials using neutron radiography

    NASA Astrophysics Data System (ADS)

    Lucero, Catherine L.

    A portion of the concrete pavements in the US have recently been observed to have premature joint deterioration. This damage is caused in part by the ingress of fluids, like water, salt water, or deicing salts. The ingress of these fluids can damage concrete when they freeze and expand or can react with the cementitious matrix causing damage. To determine the quality of concrete for assessing potential service life it is often necessary to measure the rate of fluid ingress, or sorptivity. Neutron imaging is a powerful method for quantifying fluid penetration since it can describe where water has penetrated, how quickly it has penetrated and the volume of water in the concrete or mortar. Neutrons are sensitive to light atoms such as hydrogen and thus clearly detect water at high spatial and temporal resolution. It can be used to detect small changes in moisture content and is ideal for monitoring wetting and drying in mortar exposed to various fluids. This study aimed at developing a method to accurately estimate moisture content in mortar. The common practice is to image the material dry as a reference before exposing to fluid and normalizing subsequent images to the reference. The volume of water can then be computed using the Beer-Lambert law. This method can be limiting because it requires exact image alignment between the reference image and all subsequent images. A model of neutron attenuation in a multi-phase cementitious composite was developed to be used in cases where a reference image is not available. The attenuation coefficients for water, un-hydrated cement, and sand were directly calculated from the neutron images. The attenuation coefficient for the hydration products was then back-calculated. The model can estimate the degree of saturation in a mortar with known mixture proportions without using a reference image for calculation. Absorption in mortars exposed to various fluids (i.e., deionized water and calcium chloride solutions) were investigated

  13. Secondary Waste Cast Stone Waste Form Qualification Testing Plan

    SciTech Connect

    Westsik, Joseph H.; Serne, R. Jeffrey

    2012-09-26

    The Hanford Tank Waste Treatment and Immobilization Plant (WTP) is being constructed to treat the 56 million gallons of radioactive waste stored in 177 underground tanks at the Hanford Site. The WTP includes a pretreatment facility to separate the wastes into high-level waste (HLW) and low-activity waste (LAW) fractions for vitrification and disposal. The LAW will be converted to glass for final disposal at the Integrated Disposal Facility (IDF). Cast Stone – a cementitious waste form, has been selected for solidification of this secondary waste stream after treatment in the ETF. The secondary-waste Cast Stone waste form must be acceptable for disposal in the IDF. This secondary waste Cast Stone waste form qualification testing plan outlines the testing of the waste form and immobilization process to demonstrate that the Cast Stone waste form can comply with the disposal requirements. Specifications for the secondary-waste Cast Stone waste form have not been established. For this testing plan, Cast Stone specifications are derived from specifications for the immobilized LAW glass in the WTP contract, the waste acceptance criteria for the IDF, and the waste acceptance criteria in the IDF Permit issued by the State of Washington. This testing plan outlines the testing needed to demonstrate that the waste form can comply with these waste form specifications and acceptance criteria. The testing program must also demonstrate that the immobilization process can be controlled to consistently provide an acceptable waste form product. This testing plan also outlines the testing needed 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 performance assessment analyses of the long-term environmental impact of the secondary-waste Cast Stone waste form in the IDF

  14. Mechanical resilience and cementitious processes in Imperial Roman architectural mortar

    DOE PAGESBeta

    Jackson, Marie D.; Landis, Eric N.; Brune, Philip F.; Vitti, Massimo; Chen, Heng; Li, Qinfei; Kunz, Martin; Wenk, Hans -Rudolf; Monteiro, Paulo J. M.; Ingraffea, Anthony R.

    2014-12-15

    The pyroclastic aggregate concrete of Trajan’s Markets (110 CE), now Museo Fori Imperiali in Rome, has absorbed energy from seismic ground shaking and long-term foundation settlement for nearly two millenia while remaining largely intact at the structural scale. The scientific basis of this exceptional service record is explored through computed tomography of fracture surfaces and synchroton X-ray microdiffraction analyses of a reproduction of the standardized hydrated lime–volcanic ash mortar that binds decimeter-sized tuff and brick aggregate in the conglomeratic concrete. The mortar reproduction gains fracture toughness over 180 d through progressive coalescence of calcium–aluminum-silicate–hydrate (C-A-S-H) cementing binder with Ca/(Si+Al) ≈more » 0.8–0.9 and crystallization of strätlingite and siliceous hydrogarnet (katoite) at ≥90 d, after pozzolanic consumption of hydrated lime was complete. Platey strätlingite crystals toughen interfacial zones along scoria perimeters and impede macroscale propagation of crack segments. In the 1,900 year old mortar, C-A-S-H has low Ca/(Si+Al) ≈ 0.45–0.75. Dense clusters of 2- to 30-µm strätlingite plates further reinforce interfacial zones, the weakest link of modern cement-based concrete, and the cementitious matrix. These crystals formed during long-term autogeneous reaction of dissolved calcite from lime and the alkali-rich scoriae groundmass, clay mineral (halloysite), and zeolite (phillipsite and chabazite) surface textures from the Pozzolane Rosse pyroclastic flow, erupted from the nearby Alban Hills volcano. The clast-supported conglomeratic fabric of the concrete presents further resistance to fracture propagation at the structural scale.« less

  15. Characterizing saturated mass transport in fractured cementitious materials

    NASA Astrophysics Data System (ADS)

    Akhavan, Alireza

    Concrete, when designed and constructed properly, is a durable material. However in aggressive environments concrete is prone to gradual deterioration which is due to penetration of water and aggressive agents (e.g., chloride ions) into concrete. As such, the rate of mass transport is the primary factor, controlling the durability of cementitious materials. Some level of cracking is inevitable in concrete due to brittle nature of the material. While mass transport can occur through concrete’s porous matrix, cracks can significantly accelerate the rate of mass transport and effectively influence the service life of concrete structures. To allow concrete service life prediction models to correctly account for the effect of cracks on concrete durability, mass transport thru cracks must be characterized. In this study, transport properties of cracks are measured to quantify the saturated hydraulic permeability and diffusion coefficient of cracks as a function of crack geometry (i.e.; crack width, crack tortuosity and crack wall roughness). Saturated permeability and diffusion coefficient of cracks are measured by constant head permeability test, electrical migration test, and electrical impedance spectroscopy. Plain and fiber reinforced cement paste and mortar as well as simulated crack samples are tested. The results of permeability test showed that the permeability of a crack is a function of crack width squared and can be predicted using Louis formula when crack tortuosity and surface roughness of the crack walls are accounted for. The results of the migration and impedance tests showed that the diffusion coefficient of the crack is not dependent on the crack width, but is primarily a function of volume fraction of cracks. The only parameter that is changing with the crack width is the crack connectivity. Crack connectivity was found to be linearly dependent on crack width for small crack and constant for large cracks (i.e.; approximately larger than 80 µm). The

  16. Mechanical resilience and cementitious processes in Imperial Roman architectural mortar.

    PubMed

    Jackson, Marie D; Landis, Eric N; Brune, Philip F; Vitti, Massimo; Chen, Heng; Li, Qinfei; Kunz, Martin; Wenk, Hans-Rudolf; Monteiro, Paulo J M; Ingraffea, Anthony R

    2014-12-30

    The pyroclastic aggregate concrete of Trajan's Markets (110 CE), now Museo Fori Imperiali in Rome, has absorbed energy from seismic ground shaking and long-term foundation settlement for nearly two millenia while remaining largely intact at the structural scale. The scientific basis of this exceptional service record is explored through computed tomography of fracture surfaces and synchroton X-ray microdiffraction analyses of a reproduction of the standardized hydrated lime-volcanic ash mortar that binds decimeter-sized tuff and brick aggregate in the conglomeratic concrete. The mortar reproduction gains fracture toughness over 180 d through progressive coalescence of calcium-aluminum-silicate-hydrate (C-A-S-H) cementing binder with Ca/(Si+Al) ≈ 0.8-0.9 and crystallization of strätlingite and siliceous hydrogarnet (katoite) at ≥ 90 d, after pozzolanic consumption of hydrated lime was complete. Platey strätlingite crystals toughen interfacial zones along scoria perimeters and impede macroscale propagation of crack segments. In the 1,900-y-old mortar, C-A-S-H has low Ca/(Si+Al) ≈ 0.45-0.75. Dense clusters of 2- to 30-µm strätlingite plates further reinforce interfacial zones, the weakest link of modern cement-based concrete, and the cementitious matrix. These crystals formed during long-term autogeneous reaction of dissolved calcite from lime and the alkali-rich scoriae groundmass, clay mineral (halloysite), and zeolite (phillipsite and chabazite) surface textures from the Pozzolane Rosse pyroclastic flow, erupted from the nearby Alban Hills volcano. The clast-supported conglomeratic fabric of the concrete presents further resistance to fracture propagation at the structural scale. PMID:25512521

  17. Mechanical resilience and cementitious processes in Imperial Roman architectural mortar

    SciTech Connect

    Jackson, Marie D.; Landis, Eric N.; Brune, Philip F.; Vitti, Massimo; Chen, Heng; Li, Qinfei; Kunz, Martin; Wenk, Hans -Rudolf; Monteiro, Paulo J. M.; Ingraffea, Anthony R.

    2014-12-15

    The pyroclastic aggregate concrete of Trajan’s Markets (110 CE), now Museo Fori Imperiali in Rome, has absorbed energy from seismic ground shaking and long-term foundation settlement for nearly two millenia while remaining largely intact at the structural scale. The scientific basis of this exceptional service record is explored through computed tomography of fracture surfaces and synchroton X-ray microdiffraction analyses of a reproduction of the standardized hydrated lime–volcanic ash mortar that binds decimeter-sized tuff and brick aggregate in the conglomeratic concrete. The mortar reproduction gains fracture toughness over 180 d through progressive coalescence of calcium–aluminum-silicate–hydrate (C-A-S-H) cementing binder with Ca/(Si+Al) ≈ 0.8–0.9 and crystallization of strätlingite and siliceous hydrogarnet (katoite) at ≥90 d, after pozzolanic consumption of hydrated lime was complete. Platey strätlingite crystals toughen interfacial zones along scoria perimeters and impede macroscale propagation of crack segments. In the 1,900 year old mortar, C-A-S-H has low Ca/(Si+Al) ≈ 0.45–0.75. Dense clusters of 2- to 30-µm strätlingite plates further reinforce interfacial zones, the weakest link of modern cement-based concrete, and the cementitious matrix. These crystals formed during long-term autogeneous reaction of dissolved calcite from lime and the alkali-rich scoriae groundmass, clay mineral (halloysite), and zeolite (phillipsite and chabazite) surface textures from the Pozzolane Rosse pyroclastic flow, erupted from the nearby Alban Hills volcano. The clast-supported conglomeratic fabric of the concrete presents further resistance to fracture propagation at the structural scale.

  18. Mechanical resilience and cementitious processes in Imperial Roman architectural mortar

    PubMed Central

    Landis, Eric N.; Brune, Philip F.; Vitti, Massimo; Chen, Heng; Li, Qinfei; Kunz, Martin; Wenk, Hans-Rudolf; Monteiro, Paulo J. M.; Ingraffea, Anthony R.

    2014-01-01

    The pyroclastic aggregate concrete of Trajan’s Markets (110 CE), now Museo Fori Imperiali in Rome, has absorbed energy from seismic ground shaking and long-term foundation settlement for nearly two millenia while remaining largely intact at the structural scale. The scientific basis of this exceptional service record is explored through computed tomography of fracture surfaces and synchroton X-ray microdiffraction analyses of a reproduction of the standardized hydrated lime–volcanic ash mortar that binds decimeter-sized tuff and brick aggregate in the conglomeratic concrete. The mortar reproduction gains fracture toughness over 180 d through progressive coalescence of calcium–aluminum-silicate–hydrate (C-A-S-H) cementing binder with Ca/(Si+Al) ≈ 0.8–0.9 and crystallization of strätlingite and siliceous hydrogarnet (katoite) at ≥90 d, after pozzolanic consumption of hydrated lime was complete. Platey strätlingite crystals toughen interfacial zones along scoria perimeters and impede macroscale propagation of crack segments. In the 1,900-y-old mortar, C-A-S-H has low Ca/(Si+Al) ≈ 0.45–0.75. Dense clusters of 2- to 30-µm strätlingite plates further reinforce interfacial zones, the weakest link of modern cement-based concrete, and the cementitious matrix. These crystals formed during long-term autogeneous reaction of dissolved calcite from lime and the alkali-rich scoriae groundmass, clay mineral (halloysite), and zeolite (phillipsite and chabazite) surface textures from the Pozzolane Rosse pyroclastic flow, erupted from the nearby Alban Hills volcano. The clast-supported conglomeratic fabric of the concrete presents further resistance to fracture propagation at the structural scale. PMID:25512521

  19. Exercising options

    NASA Astrophysics Data System (ADS)

    Carlowicz, Michael

    In a recent speech to graduates of the College of Computer, Mathematical, and Physical Sciences at the University of Maryland, Anne Petersen, deputy director of the National Science Foundation, encouraged a new generation of scientists to embrace opportunity and choice, and to use their scientific training as an employment credential, not a limit. In her May 23 commencement address, Petersen exhorted students to view their freshly minted diplomas as tickets to a broad and diverse job market, not just one-way trips to the laboratory.“Looking for the options and alternatives open to us—and creating options for ourselves where they are not apparent—can give us a sense of direction and volition that enriches our lives immensely…

  20. Threats to water resources from hexachlorobenzene waste at Kalush City (Ukraine)--a review of the risks and the remediation options.

    PubMed

    Lysychenko, Georgii; Weber, Roland; Kovach, Valeria; Gertsiuk, Modest; Watson, Alan; Krasnova, Iryna

    2015-10-01

    The production of chlorinated solvents such as tetrachloroethylene and tetrachloromethane has resulted in large stockpiles of unintentionally produced persistent organic pollutants (POPs) including high content of hexachlorobenzene (HCB waste). HCB waste of 15,000 t arising from the production of chlorinated solvents at the Kalush factory in Ukraine was landfilled. In 2008, it was discovered that HCB and other pollutants were escaping from the landfill into local environment including the Sapogi-Limnytsia Rivers, tributaries of the Dniester River. This showed that the HCB waste was not appropriately contained and represented a threat to the Dniester River basin. A Presidential Decree of Ukraine was therefore issued requiring remediation of the site and excavation of the waste. Between 2010 and 2013, approximately 29,445 t of HCB waste and associated contaminated soil was excavated and exported to various EU countries for incineration. This excavation revealed that these wastes can corrode through their drums within a few decades with release of pollutants. Other sites at which chlorinated solvents were produced should therefore be assessed for possible similar pollution. Despite the remediation efforts and the excavation of the landfill, the Kalush area remains a POP-contaminated site requiring further assessment. A part of the waste was exported to Poland and is stored close to the Baltic Sea and is treated in an incinerator with small capacity over a time frame of years. This case and recent similar cases reveal that the control of POP waste for destruction even in EU countries needs to be improved. PMID:26286800

  1. EVALUATION OF ON-SITE WASTEWATER TREATMENT AND DISPOSAL OPTIONS

    EPA Science Inventory

    A literature review of published and unpublished data was conducted to identify all conceivable alternative on-site systems, including wastewater manipulation, treatment and disposal options. Wastewater manipulation options included flow reduction, wasteload reduction and waste s...

  2. Effect of different dispersants in compressive strength of carbon fiber cementitious composites

    NASA Astrophysics Data System (ADS)

    Lestari, Yulinda; Bahri, Saiful; Sugiarti, Eni; Ramadhan, Gilang; Akbar, Ari Yustisia; Martides, Erie; Khaerudini, Deni S.

    2013-09-01

    Carbon Fiber Cementitious Composites (CFCC) is one of the most important materials in smart concrete applications. CFCC should be able to have the piezoresistivity properties where its resistivity changes when there is applied a stress/strain. It must also have the compressive strength qualification. One of the important additives in carbon fiber cementitious composites is dispersant. Dispersion of carbon fiber is one of the key problems in fabricating piezoresistive carbon fiber cementitious composites. In this research, the uses of dispersants are methylcellulose, mixture of defoamer and methylcellulose and superplasticizer based polycarboxylate. The preparation of composite samples is similar as in the mortar technique according to the ASTM C 109/109M standard. The additives material are PAN type carbon fibers, methylcellulose, defoamer and superplasticizer (as water reducer and dispersant). The experimental testing conducts the compressive strength and resistivity at various curing time, i.e. 3, 7 and 28 days. The results obtained that the highest compressive strength value in is for the mortar using superplasticizer based polycarboxylate dispersant. This also shown that the distribution of carbon fiber with superplasticizer is more effective, since not reacting with the cementitious material which was different from the methylcellulose that creates the cement hydration reaction. The research also found that the CFCC require the proper water cement ratio otherwise the compressive strength becomes lower.

  3. Oxidation of carbon fiber surfaces for use as reinforcement in high-temperature cementitious material systems

    DOEpatents

    Sugama, Toshifumi.

    1990-05-22

    The interfacial bond characteristics between carbon fiber and a cement matrix, in high temperature fiber-reinforced cementitious composite systems, can be improved by the oxidative treatment of the fiber surfaces. Compositions and the process for producing the compositions are disclosed. 2 figs.

  4. Cementitious Composites Engineered with Embedded Carbon Nanotube Thin Films for Enhanced Sensing Performance

    NASA Astrophysics Data System (ADS)

    Loh, Kenneth J.; Gonzalez, Jesus

    2015-07-01

    Cementitious composites such as concrete pavements are susceptible to different damage modes, which are primarily caused by repeated loading and long-term deterioration. There is even greater concern that damage could worsen and occur more frequently with the use of heavier vehicles or new aircraft carrying greater payloads. Thus, the objective of this research is to engineer cementitious composites with capabilities of self-sensing or detecting damage. The approach was to enhance the damage sensitivity of cementitious composites by incorporating multi-walled carbon nanotubes (MWNT) as part of the mix design and during casting. However, as opposed to directly dispersing MWNTs in the cement matrix, which is the current state-of-art, MWNT-based thin films were airbrushed and coated onto sand particles. The film-coated sand was then used as part of the mix design for casting mortar specimens. Mortar specimens were subjected to compressive cyclic loading tests while their electrical properties were recorded simultaneously. The results showed that the electrical properties of these cementitious composites designed with film-coated sand exhibited extremely high strain sensitivities. The electrical response was also stable and consistent between specimens.

  5. THERMALLY CONDUCTIVE CEMENTITIOUS GROUTS FOR GEOTHERMAL HEAT PUMPS. PROGRESS REPORT BY 1998

    SciTech Connect

    ALLAN,M.L.; PHILIPPACOPOULOS,A.J.

    1998-11-01

    Research commenced in FY 97 to determine the suitability of superplasticized cement-sand grouts for backfilling vertical boreholes used with geothermal heat pump (GHP) systems. The overall objectives were to develop, evaluate and demonstrate cementitious grouts that could reduce the required bore length and improve the performance of GHPs. This report summarizes the accomplishments in FY 98.

  6. Oxidation of carbon fiber surfaces for use as reinforcement in high-temperature cementitious material systems

    DOEpatents

    Sugama, Toshifumi

    1990-01-01

    The interfacial bond characteristics between carbon fiber and a cement matrix, in high temperature fiber-reinforced cementitious composite systems, can be improved by the oxidative treatment of the fiber surfaces. Compositions and the process for producing the compositions are disclosed.

  7. Predicting the Probability of Failure of Cementitious Sewer Pipes Using Stochastic Finite Element Method

    PubMed Central

    Alani, Amir M.; Faramarzi, Asaad

    2015-01-01

    In this paper, a stochastic finite element method (SFEM) is employed to investigate the probability of failure of cementitious buried sewer pipes subjected to combined effect of corrosion and stresses. A non-linear time-dependant model is used to determine the extent of concrete corrosion. Using the SFEM, the effects of different random variables, including loads, pipe material, and corrosion on the remaining safe life of the cementitious sewer pipes are explored. A numerical example is presented to demonstrate the merit of the proposed SFEM in evaluating the effects of the contributing parameters upon the probability of failure of cementitious sewer pipes. The developed SFEM offers many advantages over traditional probabilistic techniques since it does not use any empirical equations in order to determine failure of pipes. The results of the SFEM can help the concerning industry (e.g., water companies) to better plan their resources by providing accurate prediction for the remaining safe life of cementitious sewer pipes. PMID:26068092

  8. Predicting the Probability of Failure of Cementitious Sewer Pipes Using Stochastic Finite Element Method.

    PubMed

    Alani, Amir M; Faramarzi, Asaad

    2015-06-01

    In this paper, a stochastic finite element method (SFEM) is employed to investigate the probability of failure of cementitious buried sewer pipes subjected to combined effect of corrosion and stresses. A non-linear time-dependant model is used to determine the extent of concrete corrosion. Using the SFEM, the effects of different random variables, including loads, pipe material, and corrosion on the remaining safe life of the cementitious sewer pipes are explored. A numerical example is presented to demonstrate the merit of the proposed SFEM in evaluating the effects of the contributing parameters upon the probability of failure of cementitious sewer pipes. The developed SFEM offers many advantages over traditional probabilistic techniques since it does not use any empirical equations in order to determine failure of pipes. The results of the SFEM can help the concerning industry (e.g., water companies) to better plan their resources by providing accurate prediction for the remaining safe life of cementitious sewer pipes. PMID:26068092

  9. Defense Waste Processing Facility: Report of task force on options to mitigate the effect of nitrite on DWPF operations. Savannah River Site 200-S Area

    SciTech Connect

    Randall, D.; Marek, J.C.

    1992-03-01

    The possibility of accumulating ammonium nitrate (an explosive) as well as organic compounds in the DWPF Chemical Processing Cell Vent System was recently discovered. A task force was therefore organized to examine ways to avoid this potential hazard. Of thirty-two processing/engineering options screened, the task force recommended five options, deemed to have the highest technical certainty, for detailed development and evaluation: Radiolysis of nitrite in the tetraphenylborate precipitate slurry feed in a new corrosion-resistant facility. Construction of a Late Washing Facility for precipitate washing before transfer to the DWPF; ``Just-in-Time`` precipitation; Startup Workaround by radiolysis of nitrite in the existing corrosion-resistant Pump Pit tanks; Ammonia venting and organics separation in the DWPF; and, Estimated costs and schedules are included in this report.

  10. Reactive transport simulations of the evolution of a cementitious repository in clay-rich host rocks

    NASA Astrophysics Data System (ADS)

    Kosakowski, Georg; Berner, Urs; Kulik, Dmitrii A.

    2010-05-01

    In Switzerland, the deep geological disposal in clay-rich rocks is foreseen not only for high-level radioactive waste, but also for intermediate-level (ILW) and low-level (LLW) radioactive waste. Typically, ILW and LLW repositories contain huge amounts of cementitious materials used for waste conditioning, confinement, and as backfill for the emplacement caverns. We are investigating the interactions of such a repository with the surrounding clay rocks and with other clay-rich materials such as sand/bentonite mixtures that are foreseen for backfilling the access tunnels. With the help of a numerical reactive transport model, we are comparing the evolution of cement/clay interfaces for different geochemical and transport conditions. In this work, the reactive transport of chemical components is simulated with the multi-component reactive transport code OpenGeoSys-GEM. It employs the sequential non-iterative approach to couple the mass transport code OpenGeoSys (http://www.ufz.de/index.php?en=18345) with the GEMIPM2K (http://gems.web.psi.ch/) code for thermodynamic modeling of aquatic geochemical systems which is using the Gibbs Energy Minimization (GEM) method. Details regarding code development and verification can be found in Shao et al. (2009). The mineral composition and the pore solution of a CEM I 52.5 N HTS hydrated cement as described by Lothenbach & Wieland (2006) are used as an initial state of the cement compartment. The setup is based on the most recent CEMDATA07 thermodynamic database which includes several ideal solid solutions for hydrated cement minerals and is consistent with the Nagra/PSI thermodynamic database 01/01. The smectite/montmorillonite model includes cation exchange processes and amphotheric≡SOH sites and was calibrated on the basis of data by Bradbury & Baeyens (2002). In other reactive transport codes based on the Law of Mass Action (LMA) for solving geochemical equilibria, cation exchange processes are usually calculated assuming

  11. On the Application of Inertial Microfluidics for the Size-Based Separation of Polydisperse Cementitious Particulates

    NASA Astrophysics Data System (ADS)

    Kumar, Aditya; Lewis, Peter; Balonis, Magdalena; Di Carlo, Dino; Sant, Gaurav

    2015-06-01

    The early-age performance of concrete is determined by the properties of the cementitious binder and the evolution of its chemical reactions. The chemical reactivity, and to some extent, the composition of cementitious particles can depend on particle size. Therefore, it is valuable to physically separate cementing minerals into well-defined size classes so that the influences of both particle size and composition on reaction progress can be studied without the confounding effects of a broad particle size distribution. However, conventional particle separation methods (e.g., density fractionation, wet sieving, field-flow extraction, ultrasonification-sedimentation) are time-consuming and cumbersome and result in poor particle yields and size-selectivity, thus, making them unsuitable for processing larger volumes of cementitious powders (on the order of grams). This study applies a novel inertial microfluidics (IMF) based procedure to separate cementitious powders on the basis of their size. Special attention is paid to optimizing operating variables to ensure that particles in a fluid streamline achieve unique equilibrium positions within the device. From such positions, particles can be retrieved as per their size using symmetrical outlet configurations with tuned fluidic resistances. The approach is critically assessed in terms of: (1) its ability to separate cementitious powders into narrow size bins, and therefore its feasibility as a fractionation procedure, and (2) quantitatively relating the operating parameters to the particle yield and size selectivity. The study establishes metrics for assessing the ability of IMF methods to classify minerals and other polydisperse particles on the basis of their size.

  12. Solidifications/stabilization treatability study of a mixed waste sludge

    SciTech Connect

    Spence, R.D.; Stine, E.F.

    1996-03-01

    The Department of Energy Oak Ridge Operations Office signed a Federal Facility Compliance Agreement with the US Environmental Protection Agency Region IV regarding mixed wastes from the Oak Ridge Reservation (ORR) subject to the land disposal restriction provisions of the Resource Conservation and Recovery Act (RCRA). This agreement required treatability studies of solidification/stabilization (S/S) on mixed wastes from the ORR. This paper reports the results of the cementitious S/S studies conducted on a waste water treatment sludge generated from biodenitrification and heavy metals precipitation. For the cementitious waste forms, the additives tested were Portland cement, ground granulated blast furnace slag, Class F fly ash, and perlite. The properties measured on the treated waste were density, free-standing liquid, unconfined compressive strength, and TCLP performance. Spiking up to 10,000, 10,000, and 4,400 mg/kg of nickel, lead, and cadmium, respectively, was conducted to test waste composition variability and the stabilization limitations of the binding agents. The results indicated that nickel, lead and cadmium were stabilized fairly well in the high pH hydroxide-carbonate- ``bug bones`` sludge, but also clearly confirmed the established stabilization potential of cementitious S/S for these RCRA metals.

  13. Fleet servicing facilities for servicing, maintaining, and testing rail and truck radioactive waste transport systems: functional requirements, technical design concepts and options cost estimates and comparisons

    SciTech Connect

    Watson, C.D.; Hudson, B.J.; Keith, D.A.; Preston, M.K. Jr.; McCreery, P.N.; Knox, W.; Easterling, E.M.; Lamprey, A.S.; Wiedemann, G.

    1980-05-01

    This is a resource document which examines feasibility design concepts and feasibility studies of a Fleet Servicing Facility (FSF). Such a facility is intended to be used for routine servicing, preventive maintenance, and for performing requalification license compliance tests and inspections, minor repairs, and decontamination of both the transportation casks and their associated rail cars or tractor-trailers. None of the United States' waste handling plants presently receiving radioactive wastes have an on-site FSF, nor is there an existing third party facility providing these services. This situation has caused the General Accounting Office to express concern regarding the quality of waste transport system maintenance once the system is placed into service. Thus, a need is indicated for FSF's, or their equivalent, at various radioactive materials receiving sites. In this report, three forms of FSF's solely for spent fuel transport systems were examined: independent, integrated, and colocated. The independent concept was already the subject of a detailed report and is extensively referenced in this document so that capital cost comparisons of the three concepts could be made. These facilities probably could service high-level, intermediate-level, low-level, or other waste transportation systems with minor modification, but this study did not include any system other than spent fuel. Both the Integrated and Colocated concepts were assumed to be associated with some radioactive materials handling facility such as an AFR repository.

  14. Effect of Stratification on the Profile of an Anaerobic Swine Waste Treatment Lagoon in Kentucky: A Case Study for Designing Alternative Remediation Options.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An understanding of the nature of wastes in an anaerobic swine lagoon is essential in the design and operation of alternative collection, treatment, and disposal facilities for environmental quality management such as odor control, nutrient and pathogen reduction. In this study, the characterizatio...

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

    SciTech Connect

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

    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, 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

  16. Implications of theories of asteroid and comet impact for policy options for management of spent nuclear fuel and high-level radioactive wastes

    USGS Publications Warehouse

    Trask, Newell J.

    1994-01-01

    Concern with the threat posed by terrestrial asteroid and comet impacts has heightened as the catastrophic consequences of such events have become better appreciated. Although the probabilities of such impacts are very small, a reasonable question for debate is whether such phenomena should be taken into account in deciding policy for the management of spent fuel and high-level radioactive waste. The rate at which asteroid or comet impacts would affect areas of surface storage of radioactive waste is about the same as the estimated rate at which volcanic activity would affect the Yucca Mountain area. The Underground Retrievable Storage (URS) concept could satisfactorily reduce the risk from cosmic impact with its associated uncertainties in addition to providing other benefits described by previous authors.

  17. Radioactive Wastes.

    PubMed

    Choudri, B S; Baawain, Mahad

    2016-10-01

    Papers reviewed herein present a general overview of radioactive waste activities around the world in 2015. These include safety assessments, decommission and decontamination of nuclear facilities, fusion facilities, transportation and management solutions for the final disposal of low and high level radioactive wastes (LLW and HLW), interim storage and final disposal options for spent fuel (SF), and tritiated wastes, with a focus on environmental impacts due to the mobility of radionuclides in water, soil and ecosystem alongwith other progress made in the management of radioactive wastes. PMID:27620100

  18. Radioactive Wastes.

    PubMed

    Choudri, B S; Baawain, Mahad

    2015-10-01

    Papers reviewed herein present a general overview of radioactive waste activities around the world in 2014. These include safety assessments, decommission and decontamination of nuclear facilities, fusion facilities, transportation and management solutions for the final disposal of low and high level radioactive wastes (LLW and HLW), interim storage and final disposal options for spent fuel (SF), and tritiated wastes, with a focus on environmental impacts due to the mobility of radionuclides in water, soil and ecosystem alongwith other progress made in the management of radioactive wastes. PMID:26420096

  19. Home composting as an alternative treatment option for organic household waste in Denmark: An environmental assessment using life cycle assessment-modelling.

    PubMed

    Andersen, J K; Boldrin, A; Christensen, T H; Scheutz, C

    2012-01-01

    An environmental assessment of the management of organic household waste (OHW) was performed from a life cycle perspective by means of the waste-life cycle assessment (LCA) model EASEWASTE. The focus was on home composting of OHW in Denmark and six different home composting units (with different input and different mixing frequencies) were modelled. In addition, incineration and landfilling was modelled as alternatives to home composting. The most important processes contributing to the environmental impact of home composting were identified as greenhouse gas (GHG) emissions (load) and the avoided emissions in relation to the substitution of fertiliser and peat when compost was used in hobby gardening (saving). The replacement of fertiliser and peat was also identified as one of the most sensible parameters, which could potentially have a significant environmental benefit. Many of the impact categories (especially human toxicity via water (HTw) and soil (HTs)) were affected by the heavy metal contents of the incoming OHW. The concentrations of heavy metals in the compost were below the threshold values for compost used on land and were thus not considered to constitute a problem. The GHG emissions were, on the other hand, dependent on the management of the composting units. The frequently mixed composting units had the highest GHG emissions. The environmental profiles of the home composting scenarios were in the order of -2 to 16 milli person equivalents (mPE) Mg(-1) wet waste (ww) for the non-toxic categories and -0.9 to 28mPEMg(-1) ww for the toxic categories. Home composting performed better than or as good as incineration and landfilling in several of the potential impact categories. One exception was the global warming (GW) category, in which incineration performed better due to the substitution of heat and electricity based on fossil fuels. PMID:21975300

  20. Home composting as an alternative treatment option for organic household waste in Denmark: An environmental assessment using life cycle assessment-modelling

    SciTech Connect

    Andersen, J.K.; Boldrin, A.; Christensen, T.H.; Scheutz, C.

    2012-01-15

    An environmental assessment of the management of organic household waste (OHW) was performed from a life cycle perspective by means of the waste-life cycle assessment (LCA) model EASEWASTE. The focus was on home composting of OHW in Denmark and six different home composting units (with different input and different mixing frequencies) were modelled. In addition, incineration and landfilling was modelled as alternatives to home composting. The most important processes contributing to the environmental impact of home composting were identified as greenhouse gas (GHG) emissions (load) and the avoided emissions in relation to the substitution of fertiliser and peat when compost was used in hobby gardening (saving). The replacement of fertiliser and peat was also identified as one of the most sensible parameters, which could potentially have a significant environmental benefit. Many of the impact categories (especially human toxicity via water (HTw) and soil (HTs)) were affected by the heavy metal contents of the incoming OHW. The concentrations of heavy metals in the compost were below the threshold values for compost used on land and were thus not considered to constitute a problem. The GHG emissions were, on the other hand, dependent on the management of the composting units. The frequently mixed composting units had the highest GHG emissions. The environmental profiles of the home composting scenarios were in the order of -2 to 16 milli person equivalents (mPE) Mg{sup -1} wet waste (ww) for the non-toxic categories and -0.9 to 28 mPE Mg{sup -1} ww for the toxic categories. Home composting performed better than or as good as incineration and landfilling in several of the potential impact categories. One exception was the global warming (GW) category, in which incineration performed better due to the substitution of heat and electricity based on fossil fuels.

  1. A new system for crack closure of cementitious materials using shrinkable polymers

    SciTech Connect

    Jefferson, Anthony; Joseph, Christopher; Lark, Robert; Isaacs, Ben; Dunn, Simon; Weager, Brendon

    2010-05-15

    This paper presents details of an original crack-closure system for cementitious materials using shrinkable polymer tendons. The system involves the incorporation of unbonded pre-oriented polymer tendons in cementitious beams. Crack closure is achieved by thermally activating the shrinkage mechanism of the restrained polymer tendons after the cement-based material has undergone initial curing. The feasibility of the system is demonstrated in a series of small scale experiments on pre-cracked prismatic mortar specimens. The results from these tests show that, upon activation, the polymer tendon completely closes the preformed macro-cracks and imparts a significant stress across the crack faces. The potential of the system to enhance the natural autogenous crack healing process and generally improve the durability of concrete structures is addressed.

  2. Methyl methacrylate as a healing agent for self-healing cementitious materials

    NASA Astrophysics Data System (ADS)

    Van Tittelboom, K.; Adesanya, K.; Dubruel, P.; Van Puyvelde, P.; De Belie, N.

    2011-12-01

    Different types of healing agents have already been tested on their efficiency for use in self-healing cementitious materials. Generally, commercial healing agents are used while their properties are adjusted for manual crack repair and not for autonomous crack healing. Consequently, the amount of regain in properties due to self-healing of cracks is limited. In this research, a methyl methacrylate (MMA)-based healing agent was developed specifically for use in self-healing cementitious materials. Various parameters were optimized including the viscosity, curing time, strength, etc. After the desired properties were obtained, the healing agent was encapsulated and screened for its self-healing efficiency. The decrease in water permeability due to autonomous crack healing using MMA as a healing agent was similar to the results obtained for manually healed cracks. First results seem promising: however, further research needs to be undertaken in order to obtain an optimal healing agent ready for use in practice.

  3. Final Report - Assessment of Potential Phosphate Ion-Cementitious Materials Interactions

    SciTech Connect

    Naus, Dan J; Mattus, Catherine H; Dole, Leslie Robert

    2007-06-01

    The objectives of this limited study were to: (1) review the potential for degradation of cementitious materials due to exposure to high concentrations of phosphate ions; (2) provide an improved understanding of any significant factors that may lead to a requirement to establish exposure limits for concrete structures exposed to soils or ground waters containing high levels of phosphate ions; (3) recommend, as appropriate, whether a limitation on phosphate ion concentration in soils or ground water is required to avoid degradation of concrete structures; and (4) provide a "primer" on factors that can affect the durability of concrete materials and structures in nuclear power plants. An assessment of the potential effects of phosphate ions on cementitious materials was made through a review of the literature, contacts with concrete research personnel, and conduct of a "bench-scale" laboratory investigation. Results of these activities indicate that: no harmful interactions occur between phosphates and cementitious materials unless phosphates are present in the form of phosphoric acid; phosphates have been incorporated into concrete as set retarders, and phosphate cements have been used for infrastructure repair; no standards or guidelines exist pertaining to applications of reinforced concrete structures in high-phosphate environments; interactions of phosphate ions and cementitious materials has not been a concern of the research community; and laboratory results indicate similar performance of specimens cured in phosphate solutions and those cured in a calcium hydroxide solution after exposure periods of up to eighteen months. Relative to the "primer," a separate NUREG report has been prepared that provides a review of pertinent factors that can affect the durability of nuclear power plant reinforced concrete structures.

  4. Evaluation of natural colonisation of cementitious materials: effect of bioreceptivity and environmental conditions.

    PubMed

    Manso, Sandra; Calvo-Torras, María Ángeles; De Belie, Nele; Segura, Ignacio; Aguado, Antonio

    2015-04-15

    Incorporation of living organisms, such as photosynthetic organisms, on the structure envelope has become a priority in the area of architecture and construction due to aesthetical, economic and ecological advantages. Important research efforts are made to achieve further improvements, such as for the development of cementitious materials with an enhanced bioreceptivity to stimulate biological growth. Previously, the study of the bioreceptivity of cementitious materials has been carried out mainly under laboratory conditions although field-scale experiments may present different results. This work aims at analysing the colonisation of cementitious materials with different levels of bioreceptivity by placing them in three different environmental conditions. Specimens did not present visual colonisation, which indicates that environmental conditions have a greater impact than intrinsic properties of the material at this stage. Therefore, it appears that in addition to an optimized bioreceptivity of the concrete (i.e., composition, porosity and roughness), extra measures are indispensable for a rapid development of biological growth on concrete surfaces. An analysis of the colonisation in terms of genus and quantity of the most representative microorganisms found on the specimens for each location was carried out and related to weather conditions, such as monthly average temperature and total precipitation, and air quality in terms of NOx, SO2, CO and O3. OPC-based specimens presented a higher colonisation regarding both biodiversity and quantity. However, results obtained in a previous experimental programme under laboratory conditions suggested a higher suitability of Magnesium Phosphate Cement-based (MPC-based) specimens for algal growth. Consequently, carefully considering the environment and the relationships between the different organisms present in an environment is vital for successfully using a cementitious material as a substrate for biological growth. PMID

  5. Recycling of MSWI fly ash by means of cementitious double step cold bonding pelletization: Technological assessment for the production of lightweight artificial aggregates.

    PubMed

    Colangelo, Francesco; Messina, Francesco; Cioffi, Raffaele

    2015-12-15

    In this work, an extensive study on the recycling of municipal solid waste incinerator fly ash by means of cold bonding pelletization is presented. The ash comes from an incineration plant equipped with rotary and stoker furnaces, in which municipal, hospital and industrial wastes are treated. Fly ash from waste incineration is classified as hazardous and cannot be utilized or even landfilled without prior treatment. The pelletization process uses cement, lime and coal fly ash as components of the binding systems. This process has been applied to several mixes in which the ash content has been varied from 50% (wt.%) up to a maximum of 70%. An innovative additional pelletization step with only cementitious binder has been performed in order to achieve satisfactory immobilization levels. The obtained lightweight porous aggregates are mostly suitable for recovery in the field of building materials with enhanced sustainability properties. Density, water absorption and crushing strength ranged from 1000 to 1600 kg/m(3), 7 to 16% and 1.3 to 6.2 MPa, respectively, and the second pelletization step increased stabilization efficiency. The feasibility of the process has been analyzed by testing also concrete specimens containing the artificial aggregates, resulting in lightweight concrete of average performance. PMID:26124064

  6. Vitrification of hazardous and mixed wastes

    SciTech Connect

    Jantzen, C.M.; Pickett, J.B. ); Ramsey, W.G. . Dept. of Ceramic Engineering)

    1992-01-01

    Solidification of hazardous/mixed wastes into glass is being examined at the Savannah River Site. The first hazardous/mixed wastes glassified at SRS have been (1) incinerator and (2) nickel plating line (F006) wastes. Solidification of incinerator blowdown and mixtures of incinerator blowdown and incinerator bottom kiln ash have been achieved in Soda (Na[sub 2]O) - Lime (CaO) - Silica (SiO[sub 2]) glass (SLS) at waste loadings of up to 50 wt%. Solidification of nickel-plating line waste sludges containing depleted uranium have also been achieved in both SLS and borosilicate glasses at waste loadings of 75 wt%. This corresponds to volume reductions of 97% and 81%, respectively. Further studies will examine glassification of: ion exchange zeolites, inorganic filter media, asbestos, glass fiber filters, contaminated soil, cementitious, or other materials in need of remediation.

  7. Vitrification of hazardous and mixed wastes

    SciTech Connect

    Jantzen, C.M.; Pickett, J.B.; Ramsey, W.G.

    1992-10-01

    Solidification of hazardous/mixed wastes into glass is being examined at the Savannah River Site. The first hazardous/mixed wastes glassified at SRS have been (1) incinerator and (2) nickel plating line (F006) wastes. Solidification of incinerator blowdown and mixtures of incinerator blowdown and incinerator bottom kiln ash have been achieved in Soda (Na{sub 2}O) - Lime (CaO) - Silica (SiO{sub 2}) glass (SLS) at waste loadings of up to 50 wt%. Solidification of nickel-plating line waste sludges containing depleted uranium have also been achieved in both SLS and borosilicate glasses at waste loadings of 75 wt%. This corresponds to volume reductions of 97% and 81%, respectively. Further studies will examine glassification of: ion exchange zeolites, inorganic filter media, asbestos, glass fiber filters, contaminated soil, cementitious, or other materials in need of remediation.

  8. Use of polypropylene fibers coated with nano-silica particles into a cementitious mortar

    SciTech Connect

    Coppola, B. Di Maio, L.; Scarfato, P.; Incarnato, L.

    2015-12-17

    Fiber reinforced cementitious composite (FRCC) materials have been widely used during last decades in order to overcome some of traditional cementitious materials issues: brittle behaviour, fire resistance, cover spalling, impact strength. For composite materials, fiber/matrix bond plays an important role because by increasing fiber/matrix interactions is possible to increase the behaviour of the entire material. In this study, in order to improve fiber to matrix adhesion, two chemical treatments of polypropylene fibers were investigated: alkaline hydrolysis and nano-silica sol-gel particles deposition. Treatmtents effect on fibers morphology and mechanical properties was investigated by scanning electron microscopy (SEM) and tensile tests. SEM investigations report the presence of spherical nano-silica particles on fiber surface, in the case of sol-gel process, while alkaline hydrolysis leads to an increase of fibers roughness. Both treatments have negligible influence on fibers mechanical properties confirming the possibility of their use in a cementitious mortar. Pullout tests were carried out considering three embedded length of fibers in mortar samples (10, 20 and 30 mm, respectively) showing an increase of pullout energy for treated fibers. The influence on fiber reinforced mortar mechanical properties was investigated by three-point flexural tests on prismatic specimens considering two fibers length (15 and 30 mm) and two fibers volume fractions (0.50 and 1.00 %). A general increase of flexural strength over the reference mix was achieved and an overall better behaviour is recognizable for mortars containing treated fibers.

  9. Analysis of durability of advanced cementitious materials for rigid pavement construction in California

    SciTech Connect

    Kurtis, K.E.; Monteiro, P.

    1999-04-01

    Caltrans specifications for the construction of rigid pavements require rapid setting, high early strength, superior workability concrete with a desired 30+ year service life. These strict specifications provide the motivations for the investigation of advanced cementitious materials for pavement construction. The cementitious materials under consideration by Caltrans may be classified into four categories: Portland cements and blends, calcium aluminate cements and blends, calcium sulfoaluminate cements, and fly ash-based cements. To achieve the desired 30+ year design life, it is essential to select materials that are expected to exhibit long-term durability. Because most of the cementitious materials under consideration have not been extensively used for pavement construction in the United States, it is essential to characterize the long-term durability of each material. This report provides general information concerning the deleterious reactions that may damage concrete pavements in California. The reactions addressed in this report are sulfate attack, aggregate reactions, corrosion of reinforcing steel, and freeze-thaw action. Specifically, the expected performance of Portland cements and blends, calcium aluminate cements and blends, calcium sulfoaluminate cements, and fly ash-based cements are examined with regard to each of the deleterious reactions listed. Additional consideration is given to any deterioration mechanism that is particular to any of these cement types. Finally, the recommended test program for assessing potential long-term durability with respect to sulfate attack is described.

  10. A novel two-dimensional method to measure surface shrinkage in cementitious materials

    SciTech Connect

    Chen, T.C.; Ferraro, C.C.; Yin, W.Q.; Ishee, C.A.; Ifju, P.G.

    2010-05-15

    A novel experimental technique, Cure Reference Method (CRM), was developed for the measurement of surface shrinkage in cementitious materials. The technique combines the replication of diffraction grating on a specimen during the curing process and the use of high-sensitivity moire interferometry. Once demolded, the specimen was stored in an environmental chamber in order to establish specific curing conditions. Measurements were conducted on a daily basis for the duration of 7 days by recording a set of the consecutive phase shifted fringe patterns using the Portable Engineering Moire interferometer II (PEMI II). An automated fringe analysis system was developed and used to obtain displacement and strain information in two dimenzsions. Surface shrinkage behavior in both cement paste and mortar specimens was investigated by the use of the technique under controlled temperature and humidity conditions. Furthermore, an experimental control was developed in an effort to remove the effects of drying shrinkage on cementitious specimens at early ages. This was done in an effort to explore the relative contribution of autogenous shrinkage to the overall shrinkage in cementitious materials.

  11. A numerical approach for the design of multiscale fibre-reinforced cementitious composites

    NASA Astrophysics Data System (ADS)

    Montero-Chacón, Francisco; Schlangen, Erik; Cifuentes, Héctor; Medina, Fernando

    2015-10-01

    In the present work, a numerical framework for the design of new multiscale fibre-reinforced cementitious composites is presented. This is accomplished by covering three different length scales, namely the micro-, meso- and macroscale. At the microscale (here defined as ~1 mm), an enhanced fibre-reinforced lattice model is presented for the simulation of strain hardening cementitious composites. On the other hand, the analysis of fibre-reinforced concrete is performed at the mesoscale (~10 mm) by means of a novel lattice-particle model. The main variables in both models are the fibre dimensions (i.e. length and diameter), the fibre volume content and the fibre-matrix bond behaviour. Their contribution to the global mechanical properties is discussed in details. Finally, the structural characterisation of the fibre-reinforced cementitious composites (FRCC) is carried out by means of a hierarchical numerical homogenisation of the material behaviour, integrating the information obtained from lower scales into the macroscale problem (~1 m). The macroscopic response of the resulting material is characterised via three-point bending tests using a continuum damage plastic model. Although the described lattice models can be used independently as design tools in fibre cement-based composites at the micro- or mesoscale, the multiscale procedure described in this paper allows for the development of new types of FRCC by considering the effect of the multiple-scale fibre-reinforcement.

  12. Use of polypropylene fibers coated with nano-silica particles into a cementitious mortar

    NASA Astrophysics Data System (ADS)

    Coppola, B.; Di Maio, L.; Scarfato, P.; Incarnato, L.

    2015-12-01

    Fiber reinforced cementitious composite (FRCC) materials have been widely used during last decades in order to overcome some of traditional cementitious materials issues: brittle behaviour, fire resistance, cover spalling, impact strength. For composite materials, fiber/matrix bond plays an important role because by increasing fiber/matrix interactions is possible to increase the behaviour of the entire material. In this study, in order to improve fiber to matrix adhesion, two chemical treatments of polypropylene fibers were investigated: alkaline hydrolysis and nano-silica sol-gel particles deposition. Treatmtents effect on fibers morphology and mechanical properties was investigated by scanning electron microscopy (SEM) and tensile tests. SEM investigations report the presence of spherical nano-silica particles on fiber surface, in the case of sol-gel process, while alkaline hydrolysis leads to an increase of fibers roughness. Both treatments have negligible influence on fibers mechanical properties confirming the possibility of their use in a cementitious mortar. Pullout tests were carried out considering three embedded length of fibers in mortar samples (10, 20 and 30 mm, respectively) showing an increase of pullout energy for treated fibers. The influence on fiber reinforced mortar mechanical properties was investigated by three-point flexural tests on prismatic specimens considering two fibers length (15 and 30 mm) and two fibers volume fractions (0.50 and 1.00 %). A general increase of flexural strength over the reference mix was achieved and an overall better behaviour is recognizable for mortars containing treated fibers.

  13. Leaching characteristics of steel slag components and their application in cementitious property prediction.

    PubMed

    Li, Zaibo; Zhao, Sanyin; Zhao, Xuguang; He, Tusheng

    2012-01-15

    High-efficiency recovery and utilization of steel slag are important concerns for environmental protection and sustainable development. To establish a rapid method to evaluate the cementitious properties of steel slag, leaching tests were carried out on steel slag components via an evaporation-condensation method; the leaching characteristics and mechanism of the slag were also investigated. The relationship between leaching characteristics and cementitious properties, which were represented by mortar compressive strength, was analyzed. Results show that there exist significant differences among the amounts of chemically active leached components. The leaching process can be described by the shrinking unreacted core model controlled by intra-particle diffusion, and is in accordance with Kondo R hydration kinetics equation. The leaching process showed a good linear relationship between the amounts of components leached from steel slag and the mortar compressive strength of cementitious materials prepared from reference cement and steel slag with mass ratios of 50:50 and 70:30. The compressive strengths of mortars subjected to 7, 28, and 90 days of curing can be accurately predicted by the sum of leached (CaO+Al(2)O(3)) obtained after a certain length of leaching time. PMID:22088502

  14. Shock Wave Propagation in Cementitious Materials at Micro/Meso Scales

    NASA Astrophysics Data System (ADS)

    Rajendran, Arunachalam

    2015-06-01

    The mechanical and constitutive response of materials like cement, and bio materials like fish scale and abalone shell is very complex due to heterogeneities that are inherently present in the nano and microstructures. The intrinsic constitutive behaviors are driven by the chemical composition and the molecular, micro, and meso structures. Therefore, it becomes important to identify the material genome as the building block for the material. For instance, in cementitious materials, the genome of C-S-H phase (the glue or the paste) that holds the various clinkers, such as the dicalcium silicate, tricalcium silicate, calcium ferroaluminates, and others is extremely complex. Often mechanical behaviors of C-S-H type materials are influenced by the chemistry and the structures at all nano to micro length scales. By explicitly modeling the molecular structures using appropriate potentials, it is then possible to compute the elastic tensor from molecular dynamics simulations using all atom method. The elastic tensors for the C-S-H gel and other clinkers are determined using the software suite ``Accelrys Materials Studio.'' A strain rate dependent, fracture mechanics based tensile damage model has been incorporated into ABAQUS finite element code to model spall evolution in the heterogeneous cementitious material with all constituents explicitly modeled through one micron element resolution. This paper presents results from nano/micro/meso scale analyses of shock wave propagation in a heterogeneous cementitious material using both molecular dynamic and finite element codes.

  15. Physico-chemical interactions at the concrete-bitumen interface of nuclear waste repositories

    NASA Astrophysics Data System (ADS)

    Bertron, A.; Ranaivomanana, H.; Jacquemet, N.; Erable, B.; Sablayrolles, C.; Escadeillas, G.; Albrecht, A.

    2013-07-01

    This study investigates the fate of nitrate and organic acids at the bitumenconcrete-steel interface within a repository storage cell for long-lived, intermediatelevel, radioactive wastes. The interface was simulated by a multiphase system in which cementitious matrices (CEM V-paste specimens) were exposed to bitumen model leachates consisting of nitrates and acetic acid with and without oxalic acid, chemical compounds likely to be released by bitumen. Leaching experiments were conducted with daily renewal of the solutions in order to accelerate reactions. C-steel chips, simulating the presence of steel in the repository, were added in the systems for some experiments. The concentrations of anions (acetate, oxalate, nitrate, and nitrite) and cations (calcium, potassium, ammonium) and the pH were monitored over time. Mineralogical changes of the cementitious matrices were analysed by XRD. The results confirmed the stability of nitrates in the absence of steel, whereas, reduction of nitrates was observed in the presence of steel (production of NH4+). The action of acetic acid on the cementitious matrix was similar to that of ordinary leaching; no specific interaction was detected between acetate and cementitious cations. The reaction of oxalic acid with the cementitious phases led to the precipitation of calcium oxalate salts in the outer layer of the matrix. The concentration of oxalate was reduced by 65% inside the leaching medium.

  16. Selected Energy Management Options for Small Business and Local Government.

    ERIC Educational Resources Information Center

    Wert, Jonathan M.; Worthington, Barry K.

    This document is a checklist of 257 energy management options for small business and local government. The energy management options are categorized under: (1) Energy management strategies; (2) Buildings; (3) Lighting; (4) Water; (5) Waste operations; (6) Equipment; (7) Transportation; and (8) Food preparation. To select options for…

  17. Comparative analyses of spent nuclear fuel transport modal options: Transport options under existing site constraints

    SciTech Connect

    Brentlinger, L.A.; Hofmann, P.L.; Peterson, R.W.

    1989-08-01

    The movement of nuclear waste can be accomplished by various transport modal options involving different types of vehicles, transport casks, transport routes, and intermediate intermodal transfer facilities. A series of systems studies are required to evaluate modal/intermodal spent fuel transportation options in a consistent fashion. This report provides total life-cycle cost and life-cycle dose estimates for a series of transport modal options under existing site constraints. 14 refs., 7 figs., 28 tabs.

  18. Method for processing aqueous wastes

    DOEpatents

    Pickett, J.B.; Martin, H.L.; Langton, C.A.; Harley, W.W.

    1993-12-28

    A method is presented for treating waste water such as that from an industrial processing facility comprising the separation of the waste water into a dilute waste stream and a concentrated waste stream. The concentrated waste stream is treated chemically to enhance precipitation and then allowed to separate into a sludge and a supernate. The supernate is skimmed or filtered from the sludge and blended with the dilute waste stream to form a second dilute waste stream. The sludge remaining is mixed with cementitious material, rinsed to dissolve soluble components, then pressed to remove excess water and dissolved solids before being allowed to cure. The dilute waste stream is also chemically treated to decompose carbonate complexes and metal ions and then mixed with cationic polymer to cause the precipitated solids to flocculate. Filtration of the flocculant removes sufficient solids to allow the waste water to be discharged to the surface of a stream. The filtered material is added to the sludge of the concentrated waste stream. The method is also applicable to the treatment and removal of soluble uranium from aqueous streams, such that the treated stream may be used as a potable water supply. 4 figures.

  19. Method for processing aqueous wastes

    DOEpatents

    Pickett, John B.; Martin, Hollis L.; Langton, Christine A.; Harley, Willie W.

    1993-01-01

    A method for treating waste water such as that from an industrial processing facility comprising the separation of the waste water into a dilute waste stream and a concentrated waste stream. The concentrated waste stream is treated chemically to enhance precipitation and then allowed to separate into a sludge and a supernate. The supernate is skimmed or filtered from the sludge and blended with the dilute waste stream to form a second dilute waste stream. The sludge remaining is mixed with cementitious material, rinsed to dissolve soluble components, then pressed to remove excess water and dissolved solids before being allowed to cure. The dilute waste stream is also chemically treated to decompose carbonate complexes and metal ions and then mixed with cationic polymer to cause the precipitated solids to flocculate. Filtration of the flocculant removes sufficient solids to allow the waste water to be discharged to the surface of a stream. The filtered material is added to the sludge of the concentrated waste stream. The method is also applicable to the treatment and removal of soluble uranium from aqueous streams, such that the treated stream may be used as a potable water supply.

  20. Synroc processing options

    SciTech Connect

    Rozsa, R.B.; Hoenig, C.L.

    1981-09-01

    Synroc is a titanate-based ceramic material currently being developed for immobilizing high-level nuclear reactor wastes in solid form. Synroc D is a unique variation of Synroc. It can contain the high-level defense wastes, particularly those in storage at the Savannah River Plant. In this report, we review the early development of the initial Synroc process, discuss modification and other options that simplify it overall, and recommend the future direction of research and development in the processing area. A reference Synroc process is described briefly and contrasted with the Savannah River Laboratory glass-based reference case. Preliminary engineering layouts show Synroc to be a more complex processing operation and, thus, more expensive than the glass-based process. However, we believe that simplifications, which will significantly reduce the cost difference, are possible. Further research and development will continue in the areas of slurry processing, fluidized bed calcination, and mineralization. This last will use sintering, hot uniaxial pressing, or hot isostatic pressing.

  1. Thermally conductive cementitious grout for geothermal heat pump systems

    DOEpatents

    Allan, Marita

    2001-01-01

    A thermally conductive cement-sand grout for use with a geothermal heat pump system. The cement sand grout contains cement, silica sand, a superplasticizer, water and optionally bentonite. The present invention also includes a method of filling boreholes used for geothermal heat pump systems with the thermally conductive cement-sand grout. The cement-sand grout has improved thermal conductivity over neat cement and bentonite grouts, which allows shallower bore holes to be used to provide an equivalent heat transfer capacity. In addition, the cement-sand grouts of the present invention also provide improved bond strengths and decreased permeabilities. The cement-sand grouts can also contain blast furnace slag, fly ash, a thermoplastic air entraining agent, latex, a shrinkage reducing admixture, calcium oxide and combinations thereof.

  2. Encapsulation of hazardous wastes into agglomerates

    SciTech Connect

    Guloy, A.

    1992-01-28

    The objective of this study was to investigate the feasibility of using the cementitious properties and agglomeration characteristics of coal conversion byproducts to encapsulate and immobilize hazardous waste materials. The intention was to establish an economical way of co-utilization and co-disposal of wastes. In addition, it may aid in the eradication of air pollution problems associated with the fine-powdery nature of fly ash. Encapsulation into agglomerates is a novel approach of treating toxic waste. Although encapsulation itself is not a new concept, existing methods employ high-cost resins that render them economically unfeasible. In this investigation, the toxic waste was contained in a concrete-like matrix whereby fly ash and other cementitious waste materials were utilized. The method incorporates the principles of solidification, stabilization and agglomeration. Another aspect of the study is the evaluation of the agglomeration as possible lightweight aggregates. Since fly ash is commercially used as an aggregate, it would be interesting to study the effect of incorporating toxic wastes in the strength development of the granules. In the investigation, the fly ash self-cementation process was applied to electroplating sludges as the toxic waste. The process hoped to provide a basis for delisting of the waste as hazardous and, thereby greatly minimize the cost of its disposal. Owing to the stringent regulatory requirements for hauling and disposal of hazardous waste, the cost of disposal is significant. The current practice for disposal is solidifying the waste with portland cement and dumping the hardened material in the landfill where the cost varies between $700--950/ton. Partially replacing portland cement with fly ash in concrete has proven beneficial, therefore applying the same principles in the treatment of toxic waste looked very promising.

  3. WASTE OPPORTUNITY ASSESSMENT: A PHOTOFINISHING FACILITY

    EPA Science Inventory

    A waste minimization opportunity assessment was performed which identified areas for waste reduction at a photofinishing facility. The study followed procedures in the EPA Waste Minimization Opportunity Assessment Manual. The report identifies potential options to achieve further...

  4. WASTE CONTAINMENT OVERVIEW

    EPA Science Inventory

    BSE waste is derived from diseased animals such as BSE (bovine spongiform encepilopothy, also known as Mad Cow) in cattle and CWD (chronic wasting disease) in deer and elk. Landfilling is examined as a disposal option and this presentation introduces waste containment technology...

  5. Nuclear waste: A crisis of when

    SciTech Connect

    Greenberger, L.S.

    1991-07-15

    This article reviews public perception of nuclear power generation and the resulting waste in the context of waste processing and storage. The topics include public fears about nuclear waste and waste storage, no one wants waste storage in their region, low level waste storage question, the need to find a solution now, and indecision is not an option.

  6. DuraLith geopolymer waste form for Hanford secondary waste: correlating setting behavior to hydration heat evolution.

    PubMed

    Xu, Hui; Gong, Weiliang; Syltebo, Larry; Lutze, Werner; Pegg, Ian L

    2014-08-15

    The binary furnace slag-metakaolin DuraLith geopolymer waste form, which has been considered as one of the candidate waste forms for immobilization of certain Hanford secondary wastes (HSW) from the vitrification of nuclear wastes at the Hanford Site, Washington, was extended to a ternary fly ash-furnace slag-metakaolin system to improve workability, reduce hydration heat, and evaluate high HSW waste loading. A concentrated HSW simulant, consisting of more than 20 chemicals with a sodium concentration of 5 mol/L, was employed to prepare the alkaline activating solution. Fly ash was incorporated at up to 60 wt% into the binder materials, whereas metakaolin was kept constant at 26 wt%. The fresh waste form pastes were subjected to isothermal calorimetry and setting time measurement, and the cured samples were further characterized by compressive strength and TCLP leach tests. This study has firstly established quantitative linear relationships between both initial and final setting times and hydration heat, which were never discovered in scientific literature for any cementitious waste form or geopolymeric material. The successful establishment of the correlations between setting times and hydration heat may make it possible to efficiently design and optimize cementitious waste forms and industrial wastes based geopolymers using limited testing results. PMID:24952220

  7. Cast Stone Formulation for Nuclear Waste Immobilization at Higher Sodium Concentrations

    DOE PAGESBeta

    Fox, Kevin; Cozzi, Alex; Roberts, Kimberly; Edwards, Thomas

    2014-11-01

    Low activity radioactive waste at U.S. Department of Energy sites can be immobilized for permanent disposal using cementitious waste forms. This study evaluated waste forms produced with simulated wastes at concentrations up to twice that of currently operating processes. The simulated materials were evaluated for their fresh properties, which determine processability, and cured properties, which determine waste form performance. The results show potential for greatly reducing the volume of material. Fresh properties were sufficient to allow for processing via current practices. Cured properties such as compressive strength meet disposal requirements. Leachability indices provide an indication of expected long-term performance.

  8. Turning nuclear waste into glass

    SciTech Connect

    Pegg, Ian L.

    2015-02-15

    Vitrification has emerged as the treatment option of choice for the most dangerous radioactive waste. But dealing with the nuclear waste legacy of the Cold War will require state-of-the-art facilities and advanced glass formulations.

  9. Final disposal of radioactive waste

    NASA Astrophysics Data System (ADS)

    Freiesleben, H.

    2013-06-01

    In this paper the origin and properties of radioactive waste as well as its classification scheme (low-level waste - LLW, intermediate-level waste - ILW, high-level waste - HLW) are presented. The various options for conditioning of waste of different levels of radioactivity are reviewed. The composition, radiotoxicity and reprocessing of spent fuel and their effect on storage and options for final disposal are discussed. The current situation of final waste disposal in a selected number of countries is mentioned. Also, the role of the International Atomic Energy Agency with regard to the development and monitoring of international safety standards for both spent nuclear fuel and radioactive waste management is described.

  10. Early-age characteristics of red mud-coal gangue cementitious material.

    PubMed

    Zhang, Na; Sun, Henghu; Liu, Xiaoming; Zhang, Jixiu

    2009-08-15

    This experimental research was to investigate the possibility of incorporating red mud and coal gangue as raw materials for the production of red mud-coal gangue cementitious material, abbreviated as RGC, including analyses of its chemical composition, physical properties, mechanical properties and hydration products. The red mud and coal gangue (at a ratio of 3:2) were mixed together and shaped in small spheres with a water to solid ratio of 0.30 and then calcined at 600 degrees C for 2h. Subsequently, the RGC was prepared by blending 50% the resultant red mud-coal gangue mixtures, 24% blast-furnace slag, 20% clinker and 6% gypsum. The hydration products of RGC were characterized by XRD, TG-DTA and SEM-EDS. The results showed that it is feasible to use red mud and coal gangue to replace up to 50% of the raw materials to produce cementitious material, which can be called as silica-alumina based cementitious material. The hydration products of RGC are mostly ettringite, calcium hydroxide and C-S-H gel. As the dominant products, C-S-H gel and ettringite are principally responsible for the strength development of RGC in early hydration process. The content of Ca(OH)(2) initially increased but later was depleted after reaching the peak value at 21 days. Moreover, it is found that the composition of the C-S-H gel shifted towards higher Si, Al and Na contents with the increase of hydration age, whereas that of Ca shifted towards lower content. PMID:19237241

  11. Conductivity-based strain monitoring and damage characterization of fiber reinforced cementitious structural components

    NASA Astrophysics Data System (ADS)

    Hou, Tsung-Chin; Lynch, Jerome P.

    2005-05-01

    In recent years, a new class of cementitious composite has been proposed for the design and construction of durable civil structures. Termed engineered cementitious composites (ECC), ECC utilizes a low volume fraction of short fibers (polymer, steel, carbon) within a cementitious matrix resulting in a composite that strain hardens when loaded in tension. By refining the mechanical properties of the fiber-cement interface, the material exhibits high tolerance to damage. This study explores the electrical properties of ECC materials to monitor their performance and health when employed in the construction of civil structures. In particular, the conductivity of ECC changes in proportion to strain indicating that the material is piezoresistive. In this paper, the piezoresistive properties of various ECC composites are thoroughly explored. To measure the electrical resistance of ECC structures in the field, a low-cost wireless active sensing unit is proposed. The wireless active sensing unit is capable of applying DC and AC voltage signals to ECC elements while simultaneously measuring their corresponding voltages away from the signal input. By locally processing the corresponding input-output electrical signals recorded by the wireless active sensing units, the magnitude of strain in ECC elements can be calculated. In addition to measuring strain, the study seeks to correlate changes in ECC electrical properties to the magnitude of crack damage witnessed in tested specimens. A large number of ECC specimens are tested in the laboratory including a large-scale ECC bridge pier laterally loaded under cyclically repeated drift reversals. The novel self-sensing properties of ECC exploited by a wireless monitoring system hold tremendous promise for the advancement of structural health monitoring of ECC structures.

  12. Effect of Different Cooling Regimes on the Mechanical Properties of Cementitious Composites Subjected to High Temperatures

    PubMed Central

    Yu, Jiangtao; Weng, Wenfang; Yu, Kequan

    2014-01-01

    The influence of different cooling regimes (quenching in water and cooling in air) on the residual mechanical properties of engineered cementitious composite (ECC) subjected to high temperature up to 800°C was discussed in this paper. The ECC specimens are exposed to 100, 200, 400, 600, and 800°C with the unheated specimens for reference. Different cooling regimens had a significant influence on the mechanical properties of postfire ECC specimens. The microstructural characterization was examined before and after exposure to fire deterioration by using scanning electron microscopy (SEM). Results from the microtest well explained the mechanical properties variation of postfire specimens. PMID:25161392

  13. Cost-Effective Cementitious Material Compatible with Yucca Mountain Repository Geochemistry

    SciTech Connect

    Dole, LR

    2004-12-17

    The current plans for the Yucca Mountain (YM) repository project (YMP) use steel structures to stabilize the disposal drifts and connecting tunnels that are collectively over 100 kilometers in length. The potential exist to reduce the underground construction cost by 100s of millions of dollars and improve the repository's performance. These economic and engineering goals can be achieved by using the appropriate cementitious materials to build out these tunnels. This report describes the required properties of YM compatible cements and reviews the literature that proves the efficacy of this approach. This report also describes a comprehensive program to develop and test materials for a suite of underground construction technologies.

  14. Solution of the nonlinear Poisson-Boltzmann equation: Application to ionic diffusion in cementitious materials

    SciTech Connect

    Arnold, J.; Kosson, D.S.; Garrabrants, A.; Meeussen, J.C.L.; Sloot, H.A. van der

    2013-02-15

    A robust numerical solution of the nonlinear Poisson-Boltzmann equation for asymmetric polyelectrolyte solutions in discrete pore geometries is presented. Comparisons to the linearized approximation of the Poisson-Boltzmann equation reveal that the assumptions leading to linearization may not be appropriate for the electrochemical regime in many cementitious materials. Implications of the electric double layer on both partitioning of species and on diffusive release are discussed. The influence of the electric double layer on anion diffusion relative to cation diffusion is examined.

  15. Radial diffusion of radiocaesium and radioiodide through cementitious backfill

    NASA Astrophysics Data System (ADS)

    Felipe-Sotelo, M.; Hinchliff, J.; Drury, D.; Evans, N. D. M.; Williams, S.; Read, D.

    The function of the backfill material in a geological disposal facility (GDF) is to chemically condition the environment of the near field and thereby chemically retard the transport of the radionuclides present in the waste. This function of the backfill material is usually referred to as chemical containment. Diffusion experiments are being carried out over periods up to four years to assess the diffusion of Cs, Ni, Eu, Th, U and I (as I-) through Nirex Reference Vault Backfill (NRVB). The method uses cylinders of NRVB (40 mm diameter, 40-45 mm height) which can be doped via a central well with the radionuclides of interest. Diffusion occurs radially into a surrounding solution already pre-equilibrated with the cement. This paper shows the results obtained during the first two years for experiments undertaken using 137Cs and 125I- tracers with and without carrier. Comparison is made to tritiated water under identical experimental conditions. Breakthrough of Cs and I- occurred within the first week of the experiments, reaching steady state in the surrounding solution after 20-50 days. The maximum concentrations expected from the original inventories based on a simple dilution calculation have not been reached, indicating that retention in the matrix has occurred; ranging from 10% to 40% for Cs, and up to 50% for I-. Corresponding experiments using a solution containing cellulose degradation products (CDP) showed an increased diffusion for both Cs and I. Migration profiles have been obtained and the relative retention of each radionuclide has been confirmed using digital autoradiography. The results indicate that, for both isotopes, migration occurs through the cement matrix rather than through microfissures. However, whereas Cs is homogeneously distributed within the blocks, there is evidence of zones of preferential I- accumulation even where concentrations in solution have reached steady state. Transport modelling using GoldSim has replicated experimental

  16. Contaminant Release from Residual Waste in Closed Single-Shell Tanks and Other Waste Forms Associated with the Tanks

    SciTech Connect

    Deutsch, William J.

    2008-01-17

    This chapter describes the release of contaminants from the various waste forms that are anticipated to be associated with closure of the single-shell tanks. These waste forms include residual sludge or saltcake that will remain in the tanks after waste retrieval. Other waste forms include engineered glass and cementitious materials as well as contaminated soil impacted by previous tank leaks. This chapter also describes laboratory testing to quantify contaminant release and how the release data are used in performance/risk assessments for the tank waste management units and the onsite waste disposal facilities. The chapter ends with a discussion of the surprises and lessons learned to date from the testing of waste materials and the development of contaminant release models.

  17. AFCI Options Study

    SciTech Connect

    R. Wigeland; T. Taiwo; M. Todosow; W. Halsey; J. Gehin

    2009-09-01

    This report describes the background and framework for both organizing the discussion and providing information on the potential for nuclear energy R&D to develop alternative nuclear fuel cycles that would address the issues with the current implementations of nuclear power, including nuclear waste disposal, proliferation risk, safety, security, economics, and sustainability. The disposition of used fuel is the cause of many of the concerns, and the possible approaches to used fuel management identify a number of basic technology areas that need to be considered. The basic science in each of the technology areas is discussed, emphasizing what science is currently available, where scientific knowledge may be insufficient, and especially to identify specific areas where transformational discoveries may allow achievement of performance goals not currently attainable. These discussions lead to the wide range of technical options that have been the basis for past and current research and development on advanced nuclear fuel cycles in the United States. The results of this work are then briefly reviewed to show the extent to which such approaches are capable of addressing the issues with nuclear power, the potential for moving further, and the inherent limitations.

  18. RC beams shear-strengthened with fabric-reinforced-cementitious-matrix (FRCM) composite

    NASA Astrophysics Data System (ADS)

    Loreto, Giovanni; Babaeidarabad, Saman; Leardini, Lorenzo; Nanni, Antonio

    2015-12-01

    The interest in retrofit/rehabilitation of existing concrete structures has increased due to degradation and/or introduction of more stringent design requirements. Among the externally-bonded strengthening systems fiber-reinforced polymers is the most widely known technology. Despite its effectiveness as a material system, the presence of an organic binder has some drawbacks that could be addressed by using in its place a cementitious binder as in fabric-reinforced cementitious matrix (FRCM) systems. The purpose of this paper is to evaluate the behavior of reinforced concrete (RC) beams strengthened in shear with U-wraps made of FRCM. An extensive experimental program was undertaken in order to understand and characterize this composite when used as a strengthening system. The laboratory results demonstrate the technical viability of FRCM for shear strengthening of RC beams. Based on the experimental and analytical results, FRCM increases shear strength but not proportionally to the number of fabric plies installed. On the other hand, FRCM failure modes are related with a high consistency to the amount of external reinforcement applied. Design considerations based on the algorithms proposed by ACI guidelines are also provided.

  19. Reactive transport modelling of the interaction of fission product ground contamination with alkaline and cementitious leachates

    SciTech Connect

    Kwong, S.; Small, J.

    2007-07-01

    The fission products Cs-137 and Sr-90 are amongst the most common radionuclides occurring in ground contamination at the UK civil nuclear sites. Such contamination is often associated with alkaline liquids and the mobility of these fission products may be affected by these chemical conditions. Similar geochemical effects may also result from cementitious leachate associated with building foundations and the use of grouts to remediate ground contamination. The behaviour of fission products in these scenarios is a complex interaction of hydrogeological and geochemical processes. A suite of modelling tools have been developed to investigate the behaviour of a radioactive plume containing Cs and Sr. Firstly the effects of sorption due to cementitious groundwater is modelled using PHREEQC. This chemical model is then incorporated into PHAST for the 3-D reactive solute transport modeling. Results are presented for a generic scenario including features and processes that are likely to be relevant to a number of civil UK nuclear sites. Initial results show that modelling can be a very cost-effective means to study the complex hydrogeological and geochemical processes involved. Modelling can help predict the mobility of contaminants in a range of site end point scenarios, and in assessing the consequences of decommissioning activities. (authors)

  20. Thermal conductivity of cementitious grouts for geothermal heat pumps. Progress report FY 1997

    SciTech Connect

    Allan, M.L.

    1997-11-01

    Grout is used to seal the annulus between the borehole and heat exchanger loops in vertical geothermal (ground coupled, ground source, GeoExchange) heat pump systems. The grout provides a heat transfer medium between the heat exchanger and surrounding formation, controls groundwater movement and prevents contamination of water supply. Enhanced heat pump coefficient of performance (COP) and reduced up-front loop installation costs can be achieved through optimization of the grout thermal conductivity. The objective of the work reported was to characterize thermal conductivity and other pertinent properties of conventional and filled cementitious grouts. Cost analysis and calculations of the reduction in heat exchanger length that could be achieved with such grouts were performed by the University of Alabama. Two strategies to enhance the thermal conductivity of cementitious grouts were used simultaneously. The first of these was to incorporate high thermal conductivity filler in the grout formulations. Based on previous tests (Allan and Kavanaugh, in preparation), silica sand was selected as a suitable filler. The second strategy was to reduce the water content of the grout mix. By lowering the water/cement ratio, the porosity of the hardened grout is decreased. This results in higher thermal conductivity. Lowering the water/cement ratio also improves such properties as permeability, strength, and durability. The addition of a liquid superplasticizer (high range water reducer) to the grout mixes enabled reduction of water/cement ratio while retaining pumpability. Superplasticizers are commonly used in the concrete and grouting industry to improve rheological properties.

  1. Cement technology for borehole plugging: an interim report on permeability measurements of cementitious solids

    SciTech Connect

    McDaniel, E.W.

    1980-01-01

    The permeability of borehole plug solids and plug-wall rock junctions is a property of major interest in the Borehole Plugging Program. This report describes the equipment and techniques used to determine the permeabilities of possible borehole plugging materials and presents results from tests on various cementitious solids and plug-rock combinations. The cementitious solids were made from mixtures of cement, sand, salt, fly ash, and water. Three different types of cement and four different fly ashes were used. Permeabilities ranged from a high value of 3 x 10/sup -4/ darcy for a neat cement paste to a low of 5 x 10/sup -8/ darcy for a saltcrete containing 30 wt % sodium chloride. Miniature boreholes were made in the following four different types of rock: Westerly granite, Dresser basalt, Sioux quartzite, and St. Cloud granodiorite. These small holes were plugged with a mix consisting of 23 wt % Type I Portland cement, 20 wt % bituminous fy ash, 43.2 wt % sand, and 13.8 wt % water. After curing for 91 days at ambient temperature, the permeability of the plug-wall rock junctions ranged from 3 x 10/sup -5/ to < 1 x 10/sup -8/ darcy. Three of the four miniature plugged boreholes exhibited permeabilities of < 10 microdarcys.

  2. Micro-mechanics based representative volume element modeling of heterogeneous cementitious materials

    NASA Astrophysics Data System (ADS)

    Shahzamanian Sichani, Mohammadmehdi

    The current work focuses on evaluation of the effective elastic properties of cementitious materials through a voxel based FEA approach. Voxels are generated for a heterogeneous cementitious material (Type-I cement) consisting of typical volume fractions of various constituent phases from digital microstructures. The microstructure is modeled as a micro-scale representative volume element (RVE) in ABAQUS to generate cubes several tens of microns in dimension and subjected to various prescribed deformation modes to generate the effective elastic tensor of the material. The RVE-calculated elastic properties such as moduli and Poisson's ratio are validated through an asymptotic expansion homogenization (AEH) and compared with rule of mixtures. Both Periodic (PBC) and Kinematic boundary conditions (KBC) are investigated to determine if the elastic properties are invariant due to boundary conditions. In addition the method of "Windowing" was used to assess the randomness of the constituents and to validate how the isotropic elastic properties were determined. The average elastic properties obtained from the displacement based FEA of various locally anisotropic micro-size cubes extracted from an RVE of size 100x100x100 microns showed that the overall RVE response was fully isotropic. The effects of domain size, degree of hydration, kinematic and periodic boundary conditions, domain sampling techniques, local anisotropy, particle size distribution (PSD), and random microstructure on elastic properties are studied.

  3. Property investigation of calcium–silicate–hydrate (C–S–H) gel in cementitious composites

    SciTech Connect

    Hu, Chuanlin; Han, Yunge; Gao, Yueyi; Zhang, Yamei; Li, Zongjin

    2014-09-15

    Calcium–silicate–hydrate (C–S–H) gel, the main product of cement hydration, contributes the most to engineering properties of concrete. Hence, the microstructural physical and mechanical properties of C–S–H gel present in cementitious composites were investigated by the coupled nanoindentation and scanning electron microscope analysis. The physical and mechanical properties were linked through the micro-poromechanical approach. Through this study, an insight was provided into the microstructural features of C–S–H gel present in cementitious composites. It is found that C–S–H gel is a multi-scale composite composed of C–S–H solid, pore and intermixtures at the scale of nanoindentation on C–S–H gel, and the physical and mechanical properties of C–S–H gel can be influenced by the porosity and volume fraction of the intermixtures. - Highlights: • A coupled nanoindentation and scanning electron microscope technique was applied. • The physical and mechanical properties were linked by the proposed model. • The porosity and poroelastic parameters were reported for the first time. • The influence of water to cement ratio was studied.

  4. Breast Cancer: Treatment Options

    MedlinePlus

    ... Cancer - Treatment Options Request Permissions Print to PDF Breast Cancer - Treatment Options Approved by the Cancer.Net Editorial ... recommendations for ovarian ablation . Hormonal therapy for metastatic breast cancer Hormonal therapies are also commonly used to treat ...

  5. Hydration mechanism and leaching behavior of bauxite-calcination-method red mud-coal gangue based cementitious materials.

    PubMed

    Zhang, Na; Li, Hongxu; Liu, Xiaoming

    2016-08-15

    A deep investigation on the hydration mechanism of bauxite-calcination-method red mud-coal gangue based cementitious materials was conducted from viewpoints of hydration products and hydration heat analysis. As a main hydration product, the microstructure of C-A-S-H gel was observed using high resolution transmission electron microscopy. It was found that the C-A-S-H gel is composed of amorphous regions and nanocrystalline regions. Most of regions in the C-A-S-H gel are amorphous with continuous distribution, and the nanocrystalline regions on scale of ∼5nm are dispersed irregularly within the amorphous regions. The hydration heat of red mud-coal gangue based cementitious materials is much lower than that of the ordinary Portland cement. A hydration model was proposed for this kind of cementitious materials, and the hydration process mainly consists of four stages which are dissolution of materials, formation of C-A-S-H gels and ettringite, cementation of hydration products, and polycondensation of C-A-S-H gels. There are no strict boundaries among these four basic stages, and they proceed crossing each other. Moreover, the leaching toxicity tests were also performed to prove that the developed red mud-coal gangue based cementitious materials are environmentally acceptable. PMID:27131457

  6. Self-cementitious properties of fly ashes from CFBC boilers co-firing coal and high-sulphur petroleum coke

    SciTech Connect

    Sheng Guanghong; Li Qin; Zhai Jianping . E-mail: jpzhai@nju.edu.cn; Li Feihu

    2007-06-15

    Self-cementitious properties of fly ash from circulating fluidized bed combustion boiler co-firing coal and high-sulphur petroleum coke (CPFA) were investigated. CPFA was self-cementitious which was affected by its fineness and chemical compositions, especially the contents of SO{sub 3} and free lime (f-CaO). Higher contents of SO{sub 3} and f-CaO were beneficial to self-cementitious strength; the self-cementitious strength increases with a decrease of its 45 {mu}m sieve residue. The expansive ratio of CPFA hardened paste was high because of generation of ettringite (AFt), which was influenced by its water to binder ratio (W/A), curing style and grinding of the ash. The paste cured in water had the highest expansive ratio, and grinding of CPFA was beneficial to its volume stability. The hydration products of CPFA detected by X-ray diffraction (XRD) and scanning electron microscopy (SEM) were portlandite, gypsum, AFt and hydrated calcium silicate (C-S-H)

  7. Modelling the carbonation of cementitious matrixes by means of the unreacted-core model, UR-CORE

    SciTech Connect

    Castellote, M. Andrade, C.

    2008-12-15

    This paper presents a model for the carbonation of cementitious matrixes (UR-CORE). The model is based on the principles of the 'unreacted-core' systems, typical of chemical engineering processes, in which the reacted product remains in the solid as a layer of inert ash, adapted for the specific case of carbonation. Development of the model has been undertaken in three steps: 1) Establishment of the controlling step in the global carbonation rate, by using data of fractional conversion of different phases of the cementitious matrixes, obtained by the authors through neutron diffraction data experiments, and reported in [M. Castellote, C. Andrade, X. Turrillas, J. Campo, G. Cuello, Accelerated carbonation of cement pastes in situ monitored by neutron diffraction, Cem. Concr. Res. (2008), doi:10.1016/j.cemconres.2008.07.002]. 2) Then, the model has been adapted and applied to the cementitious materials using different concentrations of CO{sub 2}, with the introduction of the needed assumptions and factors. 3) Finally, the model has been validated with laboratory data at different concentrations (taken from literature) and for long term natural exposure of concretes. As a result, the model seems to be reliable enough to be applied to cementitious materials, being able to extrapolate the results from accelerated tests in any conditions to predict the rate of carbonation in natural exposure, being restricted, at present stage, to conditions with a constant relative humidity.

  8. Disposition Options for Hanford Site K-Basin Spent Nuclear Fuel Sludge

    SciTech Connect

    Mellinger, George B.; Delegard, Calvin H.; Gerber, Mark A.; Naft, Barry N.; Schmidt, Andrew J.; Walton, Terry L.

    2004-01-18

    This report provides summary-level information about a group of options that have been identified for the disposition of spent-nuclear-fuel sludge in the K-Basins at the Hanford Site. These options are representative of the range of likely candidates that may be considered for disposition of the sludge. The product of each treatment option would be treated sludge that would meet waste acceptance requirements for disposal as transuranic (TRU) waste at the Waste Isolation Pilot Plant (WIPP).

  9. Mine Drainage Generation and Control Options.

    PubMed

    Wei, Xinchao; Rodak, Carolyn M; Zhang, Shicheng; Han, Yuexin; Wolfe, F Andrew

    2016-10-01

    This review provides a snapshot of papers published in 2015 relevant to the topic of mine drainage generation and control options. The review is broken into 3 sections: Generation, Prediction and Prevention, and Treatment Options. The first section, mine drainage generation, focuses on the characterization of mine drainage and the environmental impacts. As such, it is broken into three subsections focused on microbiological characterization, physiochemical characterization, and environmental impacts. The second section of the review is divided into two subsections focused on either the prediction or prevention of acid mine drainage. The final section focuses on treatment options for mine drainage and waste sludge. The third section contains subsections on passive treatment, biological treatment, physiochemical treatment, and a new subsection on beneficial uses for mine drainage and treatment wastes. PMID:27620096

  10. Disposition options for {sup 233}U

    SciTech Connect

    Forsberg, C.W.; Icenhour, A.S.; Krichinsky, A.M.

    1998-04-27

    The United States is implementing a program to dispose of excess nuclear-weapons-usable materials--including {sup 233}U. A series of studies have identified multiple {sup 233}U disposition options, and these options are described herein. Most of the options involve adding depleted uranium containing {sup 238}U to the {sup 233}U. Converting the {sup 233}U into a mixture of <12 wt % {sup 233}U in {sup 238}U converts the weapons-usable {sup 233}U into nonweapons-usable {sup 233}U. For {sup 233}U that is considered waste, further isotopic dilution to <0.66 wt % {sup 233}U in {sup 238}U minimizes potential long-term repository criticality concerns and in many cases minimizes final waste volumes.

  11. X-ray computed microtomography of three-dimensional microcracks and self-healing in engineered cementitious composites

    NASA Astrophysics Data System (ADS)

    Fan, Shuai; Li, Mo

    2015-01-01

    Concrete cracking and deterioration can potentially be addressed by innovative self-healing cementitious materials, which can autogenously regain transport properties and mechanical characteristics after the damage self-healing process. For the development of such materials, it is crucial, but challenging, to precisely characterize the extent and quality of self-healing due to a variety of factors. This study adopted x-ray computed microtomography (μCT) to derive three-dimensional morphological data on microcracks before and after healing in engineered cementitious composite (ECC). Scanning electron microscope and energy dispersive x-ray spectroscopy were also used to morphologically and chemically analyze the healing products. This work showed that the evolution of the microcrack 3D structure due to self-healing in cementitious materials can be directly and quantitatively characterized by μCT. A detailed description of the μCT image analysis method applied to ECC self-healing was presented. The results revealed that the self-healing extent and rate strongly depended on initial surface crack width, with smaller crack width favoring fast and robust self-healing. We also found that the self-healing mechanism in cementitious materials is dependent on crack depth. The region of a crack close to the surface (from 0 to around 50-150 μm below the surface) can be sealed quickly with crystalline precipitates. However, at greater depths the healing process inside the crack takes a significantly longer time to occur, with healing products more likely resulting from continued hydration and pozzolanic reactions. Finally, the μCT method was compared with other self-healing characterization methods, with discussions on its importance in generating new scientific knowledge for the development of robust self-healing cementitious materials.

  12. Solidification of low-level radioactive waste at the Savannah River Site

    SciTech Connect

    Langton, C.A.

    1989-01-01

    Aqueous-based process waste and other small volume wastes including basin sludge and incinerator ash will be solidified in cement-based wasteforms at SRS. A variety of inorganic solidifying agents are used depending on the chemistry, contaminants, and processing characteristics of the waste. In some cases, pre-treatment of the waste is used to reduce the activity of the waste and/or to remove the hazardous characteristics of the waste. In the case of DWPF saltstone, pretreatment is used to reduce 137 Cs and 90 Sr concentration to Class A levels and in-situ treatment (chemical reactions between the cementitious solids and waste) is used to remove the toxic metal characteristic of the waste. Chemical reduction of the Cr/sup +6/ to Cr/sup +3/ and subsequent precipitation of Cr(OH)/sub 3/, (low solubility) occurs as the result of reactions between the cementitious raw materials and the waste liquid. In summary waste treatment and solidification used at SRS is designed to meet both South Carolina and Federal requirements for maintaining the quality of the groundwater at the disposal site boundary. 2 refs.

  13. 40 CFR 262.202 - This subpart is optional.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Waste Determination and Accumulation of Unwanted Material for Laboratories Owned by Eligible Academic...: Eligible academic entities have the option of complying with this subpart with respect to its laboratories... exempt small quantity generators. Eligible academic entities have the option of complying with...

  14. 40 CFR 262.202 - This subpart is optional.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Waste Determination and Accumulation of Unwanted Material for Laboratories Owned by Eligible Academic...: Eligible academic entities have the option of complying with this subpart with respect to its laboratories... exempt small quantity generators. Eligible academic entities have the option of complying with...

  15. Physical and mechanical properties of mortars containing PET and PC waste aggregates.

    PubMed

    Hannawi, Kinda; Kamali-Bernard, Siham; Prince, William

    2010-11-01

    Non-biodegradable plastic aggregates made of polycarbonate (PC) and polyethylene terephthalate (PET) waste are used as partial replacement of natural aggregates in mortar. Various volume fractions of sand 3%, 10%, 20% and 50% are replaced by the same volume of plastic. This paper investigates the physical and mechanical properties of the obtained composites. The main results of this study show the feasibility of the reuse of PC and PET waste aggregates materials as partial volume substitutes for natural aggregates in cementitious materials. Despite of some drawbacks like a decrease in compressive strength, the use of PC and PET waste aggregates presents various advantages. A reduction of the specific weight of the cementitious materials and a significant improvement of their post-peak flexural behaviour are observed. The calculated flexural toughness factors increase significantly with increasing volume fraction of PET and PC-aggregates. Thus, addition of PC and PET plastic aggregates in cementitious materials seems to give good energy absorbing materials which is very interesting for several civil engineering applications like structures subjected to dynamic or impact efforts. The present study has shown quite encouraging results and opened new way for the recycling of PC waste aggregate in cement and concrete composites. PMID:20417085

  16. Secondary Waste Form Screening Test Results—THOR® Fluidized Bed Steam Reforming Product in a Geopolymer Matrix

    SciTech Connect

    Pires, Richard P.; Westsik, Joseph H.; Serne, R. Jeffrey; Mattigod, Shas V.; Golovich, Elizabeth C.; Valenta, Michelle M.; Parker, Kent E.

    2011-07-14

    Screening tests are being conducted to evaluate waste forms for immobilizing secondary liquid wastes from the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Plans are underway to add a stabilization treatment unit to the Effluent Treatment Facility to provide the needed capacity for treating these wastes from WTP. The current baseline is to use a Cast Stone cementitious waste form to solidify the wastes. Through a literature survey, DuraLith alkali-aluminosilicate geopolymer, fluidized-bed steam reformation (FBSR) granular product encapsulated in a geopolymer matrix, and a Ceramicrete phosphate-bonded ceramic were identified both as candidate waste forms and alternatives to the baseline. These waste forms have been shown to meet waste disposal acceptance criteria, including compressive strength and universal treatment standards for Resource Conservation and Recovery Act (RCRA) metals (as measured by the toxicity characteristic leaching procedure [TCLP]). Thus, these non-cementitious waste forms should also be acceptable for land disposal. Information is needed on all four waste forms with respect to their capability to minimize the release of technetium. Technetium is a radionuclide predicted to be in the secondary liquid wastes in small quantities, but the Integrated Disposal Facility (IDF) risk assessment analyses show that technetium, even at low mass, produces the largest contribution to the estimated IDF disposal impacts to groundwater.

  17. Effects of Using Silica Fume and Polycarboxylate-Type Superplasticizer on Physical Properties of Cementitious Grout Mixtures for Semiflexible Pavement Surfacing

    PubMed Central

    Karim, Mohamed Rehan; Mahmud, Hilmi; Mashaan, Nuha S.; Katman, Herdayati; Husain, Nadiah Md

    2014-01-01

    Semi-flexible pavement surfacing is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement, which is subsequently grouted with appropriate cementitious materials. This study aims to investigate the compressive strength, flexural strength, and workability performance of cementitious grout. The grout mixtures are designed to achieve high strength and maintain flow properties in order to allow the cement slurries to infiltrate easily through unfilled compacted skeletons. A paired-sample t-test was carried out to find out whether water/cement ratio, SP percentages, and use of silica fume influence the cementitious grout performance. The findings showed that the replacement of 5% silica fume with an adequate amount of superplasticizer and water/cement ratio was beneficial in improving the properties of the cementitious grout. PMID:24526911

  18. Performance Impact of Fast Flow Paths Through Grout Monoliths Used for Radioactive Waste Disposal - 13224

    SciTech Connect

    Dinwiddie, Cynthia L.; Walter, Gary R.; Esh, David W.; Barr, Cynthia S.

    2013-07-01

    Empty HLW handling and storage tanks at SRS and INL contain residual radioactivity; these tanks are being stabilized with cementitious grout during closure operations. The US NRC directed the Center for Nuclear Waste Regulatory Analyses (CNWRA{sup R}) to develop physical analogs of cementitious grout monoliths to investigate their potential to form fast flow pathways such as macro-cracks, separations between grout lifts, and annuli around pipes, supports, and along tank walls. CNWRA developed and tested 15 55-gal-drum-scale specimens and 2 larger specimens of tank-filling cementitious grout, and 9 specimens of pipe-filling grout. These experiments demonstrated that the size of fast flow pathways that develop and the peak temperatures attained during hydration are proportional to the scale of the specimen, and that annular apertures and bulk grout permeability generally increased with time post-placement. Cracks developed overnight following placement of each grout lift in the largest specimen, but developed more slowly in smaller specimens, perhaps due to a ∼20 deg. C difference in peak temperatures, which influence the thermal gradients that can induce cracking. Plastic and drying shrinkage commonly led to poor grout-to-metal and grout-to-grout bonding. Cracks, annular gaps, and grout flow lobe seams transmitted fluids during injection testing. Macro-scale flow pathways such as these are not readily observed in bench-scale specimens of cementitious tank grout. (authors)

  19. Aqueous Cr (VI) removal by Friedel's salt adsorbent prepared from calcium aluminate-rich cementitious materials.

    PubMed

    Jiang, Yonghai; Yang, Yu; Qian, Guangren; Hou, Hetian; Xi, Beidou; Xu, Yunfeng

    2015-01-01

    This research paper investigated a novel absorbent of calcium aluminate-rich cementitious materials (Friedel's salt adsorbent, FA) for aqueous hexavalent chromium (VI) removal. The adsorption kinetics showed that the maximum adsorption capacities of FA were 3.36, 14.66, and 26.17 mg/g when the initial Cr(VI) concentration was 10, 50, and 100 mg/L, respectively. The adsorption fitted with the pseudo-second-order kinetic model, suggesting the important roles of intercalation in the adsorption process with increasing Cr(VI) concentrations. This Friedel's salt adsorbent is suggested as an adaptive and effective adsorbent for Cr(VI) removal in contaminated groundwater. PMID:25798557

  20. Influence of cementitious additions on rheological and mechanical properties of reactive powder concretes

    NASA Astrophysics Data System (ADS)

    Zenati, A.; Arroudj, K.; Lanez, M.; Oudjit, M. N.

    2009-11-01

    Following needs of concrete market and the economic and ecological needs, several researchers, all over the world, studied the beneficial effect which the incorporation of the mineral additions in Portland cement industry can bring. It was shown that the incorporation of local mineral additions can decrease the consumption of crushing energy of cements, and reduce the CO2 emission. Siliceous additions, moreover their physical role of filling, play a chemical role pozzolanic. They contribute to improving concrete performances and thus their durability. The abundance of dunes sand and blast furnace slag in Algeria led us to study their effect like cementitious additions. The objective of this paper is to study the effect of the incorporation of dunes sand and slag, finely ground on rheological and mechanical properties of reactive powder concretes containing ternary binders.

  1. Development of New Cementitious Caterials by Alkaline Activating Industrial by-Products

    NASA Astrophysics Data System (ADS)

    Fernández-Jimenez, A.; García-Lodeiro, I.; Palomo, A.

    2015-11-01

    The alkaline activation of aluminosiliceous industrial by-products such as blast furnace slag and fly ash is widely known to yield binders whose properties make them comparable to or even stronger and more durable than ordinary Portland cement. The present paper discusses activation fundamentals (such as the type and concentration of alkaline activator and curing conditions) as well as the structure of the cementitious gels formed (C-A-S-H, N-A-S-H). The durability and strength of these systems make these materials apt for use in many industrial applications, such as precast concrete elements (masonery blocks, railroad sleepers), protective coatings for materials with low fire ratings and lightweight elements.

  2. FUNDAMENTAL PROPERTIES OF ULTRA HIGH PERFORMANCE-STRAIN HARDENING CEMENTITIOUS COMPOSITES AND USAGE FOR REPAIR

    NASA Astrophysics Data System (ADS)

    Kunieda, Minoru; Shimizu, Kosuke; Eguchi, Teruyuki; Ueda, Naoshi; Nakamura, Hikaru

    This paper presents the fundamental properties of Ultra High Performance-Strain Hardening Cementitious Composites (UHP-SHCC), which were depeloped for repair applications. In particular, mechanical properties such as tensile response, shrinkage and bond strength were investigated experimentally. Protective performance of the material such as air permeability, water permeability and penetration of chloride ion was also confirmed comparing to that of ordinary concrete. This paper also introduces the usage of the material in repair of concrete st ructures. Laboratory tests concerining the deterioration induced by corrosion were conducted. The UHP-SHCC that coverd the RC beam resisted not only crack opening along the rebar due to corrosion but also crack opening due to loading tests.

  3. Hydration mechanism of a cementitious material prepared with Si-Mn slag

    NASA Astrophysics Data System (ADS)

    Zhang, Xu-Fang; Ni, Wen; Wu, Jun-Yu; Zhu, Li-Ping

    2011-04-01

    A cementitious material was prepared by mixing 80wt% Si-Mn slag powder, 10wt% lime, and 10wt% anhydrite. The compressive strength of mortar samples reaches 51.48 MPa after 28 d curing. The analyses of X-ray diffraction (XRD) and scanning electron microscopy (SEM) show that much ettringite is formed in the sample cured for 3 d, and C-S-H gel increases rapidly during subsequent curing. Nuclear magnetic resonance (NMR) analysis of 29Si and 27Al and infrared spectroscopy (IR) analysis show that aluminum decomposition from tetrahedral network of the slag glass and its subsequent migration and re-combination play an important role in the process of hydration and strength development of the samples.

  4. Multiscale characterization of chemical–mechanical interactions between polymer fibers and cementitious matrix

    SciTech Connect

    Hernández-Cruz, Daniel; Hargis, Craig W.; Bae, Sungchul; Itty, Pierre A.; Meral, Cagla; Dominowski, Jolee; Radler, Michael J.; Kilcoyne, David A.; Monteiro, Paulo J. M.

    2014-04-01

    Together with a series of mechanical tests, the interactions and potential bonding between polymeric fibers and cementitious materials were studied using scanning transmission X-ray microscopy (STXM) and microtomography (lCT). Experimental results showed that these techniques have great potential to characterize the polymer fiber-hydrated cement-paste matrix interface, as well as differentiating the chemistry of the two components of a bi-polymer (hybrid) fiber the polypropylene core and the ethylene acrylic acid copolymer sheath. Similarly, chemical interactions between the hybrid fiber and the cement hydration products were observed, indicating the chemical bonding between the sheath and the hardened cement paste matrix. Microtomography allowed visualization of the performance of the samples, and the distribution and orientation of the two types of fiber in mortar. Beam flexure tests confirmed improved tensile strength of mixes containing hybrid fibers, and expansion bar tests showed similar reductions in expansion for the polypropylene and hybrid fiber mortar bars.

  5. Characterization of bond in steel-fiber-reinforced cementitious composites under tensile loads

    SciTech Connect

    Namur, G.G.

    1989-01-01

    Investigated was bonding in steel fiber reinforced cementitious composites, like fiber-reinforced mortar. The study was basically analytical, consisting primarily of two analytical models that predict the bond shear stress distribution at the interface between the fibers and the matrix, as well as the normal tensile distributions in the fibers and the matrix. The two models were, however, based on separate assumptions. While the first model assumed a known bond shear stress versus slip relationship at the interface between the fibers and the surrounding matrix, the second model was based on a mechanism of force transfer between the fibers and the matrix, hence circumventing the rather complex task of determining the relationship between the bond stress and the slip for the given type of fiber and matrix. Some applications to this second model, such as the bond modulus, the debonding stress, the length of the debonded zone were also investigated. A theoretical study of the pull-out process of steel fibers in cementitious matrices is included. The problem consisted of relating an idealized bond shear stress versus slip relationship to a pull-out curve. The derivation as based on the assumption that this relationship is linearly elastic-perfectly frictional, and then extended to the case of a fiction decaying linearly with the slip. The problem was subdivided into two components: a primal problem, whereby the pull-out curve is predicted from an assumed bond shear stress-slip relationship, and the dual problem, in which an experimentally obtained pull-out curve was used to predict the interfacial constitutive model, namely the bond-slip curve. Model application was illustrated by three examples of pull-out tests. The pull-out curves obtained in the laboratory, which featured the pull-out force versus the end slip of the pull-out fiber, were used to predict bond shear stress-slip relationships.

  6. Grout treatment facility dangerous waste permit application

    SciTech Connect

    Not Available

    1992-07-01

    The Grout Treatment Facility (GTF) will provide permanent disposal for approximately 43 Mgal of low-level radioactive liquid waste currently being stored in underground tanks on the Hanford Site. The first step in permanent disposal is accomplished by solidifying the liquid waste with cementitious dry materials. The resulting grout is cast within underground vaults. This report on the GTF contains information on the following: Geologic data, hydrologic data, groundwater monitoring program, information, detection monitoring program, groundwater characterization drawings, building emergency plan--grout treatment facility, response action plan for grout treatment facility, Hanford Facility contingency plan, training course descriptions, overview of the Hanford Facility Grout Performance, assessment, bland use and zoning map, waste minimization plan, cover design engineering report, and clay liners (ADMIXTURES) in semiarid environments.

  7. Facing America's trash: What next for municipal solid waste. Summary report

    SciTech Connect

    Not Available

    1990-01-01

    The contents of this study include: policy options; enhancing the institutional framework; specific msw program options; (waste prevention, recycling, incineration, landfills); and concluding remarks.

  8. Mixed Low-Level Radioactive Waste (MLLW) Primer

    SciTech Connect

    W. E. Schwinkendorf

    1999-04-01

    This document presents a general overview of mixed low-level waste, including the regulatory definitions and drivers, the manner in which the various kinds of mixed waste are regulated, and a discussion of the waste treatment options.

  9. Approximate option pricing

    SciTech Connect

    Chalasani, P.; Saias, I.; Jha, S.

    1996-04-08

    As increasingly large volumes of sophisticated options (called derivative securities) are traded in world financial markets, determining a fair price for these options has become an important and difficult computational problem. Many valuation codes use the binomial pricing model, in which the stock price is driven by a random walk. In this model, the value of an n-period option on a stock is the expected time-discounted value of the future cash flow on an n-period stock price path. Path-dependent options are particularly difficult to value since the future cash flow depends on the entire stock price path rather than on just the final stock price. Currently such options are approximately priced by Monte carlo methods with error bounds that hold only with high probability and which are reduced by increasing the number of simulation runs. In this paper the authors show that pricing an arbitrary path-dependent option is {number_sign}-P hard. They show that certain types f path-dependent options can be valued exactly in polynomial time. Asian options are path-dependent options that are particularly hard to price, and for these they design deterministic polynomial-time approximate algorithms. They show that the value of a perpetual American put option (which can be computed in constant time) is in many cases a good approximation to the value of an otherwise identical n-period American put option. In contrast to Monte Carlo methods, the algorithms have guaranteed error bounds that are polynormally small (and in some cases exponentially small) in the maturity n. For the error analysis they derive large-deviation results for random walks that may be of independent interest.

  10. The Origins of Options

    PubMed Central

    Smaldino, Paul E.; Richerson, Peter J.

    2012-01-01

    Most research on decision making has focused on how human or animal decision makers choose between two or more options, posed in advance by the researchers. The mechanisms by which options are generated for most decisions, however, are not well understood. Models of sequential search have examined the trade-off between continued exploration and choosing one’s current best option, but still cannot explain the processes by which new options are generated. We argue that understanding the origins of options is a crucial but untapped area for decision making research. We explore a number of factors which influence the generation of options, which fall broadly into two categories: psycho-biological and socio-cultural. The former category includes factors such as perceptual biases and associative memory networks. The latter category relies on the incredible human capacity for culture and social learning, which doubtless shape not only our choices but the options available for choice. Our intention is to start a discussion that brings us closer toward understanding the origins of options. PMID:22514515

  11. Modeling of early age loss of lithium ions from pore solution of cementitious systems treated with lithium nitrate

    SciTech Connect

    Kim, Taehwan Olek, Jan

    2015-01-15

    Addition of lithium nitrate admixture to the fresh concrete mixture helps to minimize potential problems related to alkali-silica reaction. For this admixture to function as an effective ASR control measure, it is imperative that the lithium ions remain in the pore solution. However, it was found that about 50% of the originally added lithium ions are removed from the pore solution during early stages of hydration. This paper revealed that the magnitude of the Li{sup +} ion loss is highly dependent on the concentration of Li{sup +} ions in the pore solution and the hydration rate of the cementitious systems. Using these findings, an empirical model has been developed which can predict the loss of Li{sup +} ions from the pore solution during the hydration period. The proposed model can be used to investigate the effects of mixture parameters on the loss of Li{sup +} ions from the pore solution of cementitious system.

  12. A test method for determining adhesion forces and Hamaker constants of cementitious materials using atomic force microscopy

    SciTech Connect

    Lomboy, Gilson; Sundararajan, Sriram; Wang Kejin; Subramaniam, Shankar

    2011-11-15

    A method for determining Hamaker constant of cementitious materials is presented. The method involved sample preparation, measurement of adhesion force between the tested material and a silicon nitride probe using atomic force microscopy in dry air and in water, and calculating the Hamaker constant using appropriate contact mechanics models. The work of adhesion and Hamaker constant were computed from the pull-off forces using the Johnson-Kendall-Roberts and Derjagin-Muller-Toropov models. Reference materials with known Hamaker constants (mica, silica, calcite) and commercially available cementitious materials (Portland cement (PC), ground granulated blast furnace slag (GGBFS)) were studied. The Hamaker constants of the reference materials obtained are consistent with those published by previous researchers. The results indicate that PC has a higher Hamaker constant than GGBFS. The Hamaker constant of PC in water is close to the previously predicted value C{sub 3}S, which is attributed to short hydration time ({<=} 45 min) used in this study.

  13. Acoustic emission monitoring of cement-based structures immobilising radioactive waste

    SciTech Connect

    Spasova, L.M.; Ojovan, M.I.; Hayes, M.; Godfrey, H.

    2007-07-01

    The long term performance of cementitious structures immobilising radioactive waste can be affected by physical and chemical processes within the encapsulating materials such as formation of new phases (e.g., vaterite, brucite), degradation of cement phases (e.g., CSH gel, portlandite), degradation of some waste components (e.g., organics), corrosion of metallic constituents (aluminium, magnesium), gas emission, further hydration etc. The corrosion of metals in the high pH cementitious environment is of especial concern as it can potentially cause wasteform cracking. One of the perspective non-destructive methods used to monitor and assess the mechanical properties of materials and structures is based on an acoustic emission (AE) technique. In this study an AE non-destructive technique was used to evaluate the mechanical performance of cementitious structures with encapsulated metallic waste such as aluminium. AE signals generated as a result of aluminium corrosion in a small-size blast furnace slag (BFS)/ordinary Portland cement (OPC) sample were detected, recorded and analysed. A procedure for AE data analysis including conventional parameter-based AE approach and signal-based analysis was applied and demonstrated to provide information on the aluminium corrosion process and its impact on the mechanical performance of the encapsulating cement matrix. (authors)

  14. The Influence of Nano-Fe3O4 on the Microstructure and Mechanical Properties of Cementitious Composites.

    PubMed

    Sikora, Pawel; Horszczaruk, Elzbieta; Cendrowski, Krzysztof; Mijowska, Ewa

    2016-12-01

    In the last decade, nanotechnology has been gathering a spectacular amount of attention in the field of building materials. The incorporation of nanosized particles in a small amount to the building materials can influence their properties significantly. And it can contribute to the creation of novel and sustainable structures. In this work, the effect of nano-Fe3O4 as an admixture (from 1 to 5 wt.% in mass of the cement) on the mechanical and microstructural properties of cementitious composites has been characterised. The study showed that Fe3O4 nanoparticles acted as a filler which improved the microstructure of a cementitious composite and reduced its total porosity, thus increasing the density of the composite. The presence of nanomagnetite did not affect the main hydration products and the rate of cement hydration. In addition, the samples containing nanomagnetite exhibited compressive strength improvement (up to 20 %). The study showed that 3 wt.% of nano-Fe3O4 in the cementitious composite was the optimal amount to improve both its mechanical and microstructural properties. PMID:27067730

  15. The Influence of Nano-Fe3O4 on the Microstructure and Mechanical Properties of Cementitious Composites

    NASA Astrophysics Data System (ADS)

    Sikora, Pawel; Horszczaruk, Elzbieta; Cendrowski, Krzysztof; Mijowska, Ewa

    2016-04-01

    In the last decade, nanotechnology has been gathering a spectacular amount of attention in the field of building materials. The incorporation of nanosized particles in a small amount to the building materials can influence their properties significantly. And it can contribute to the creation of novel and sustainable structures. In this work, the effect of nano-Fe3O4 as an admixture (from 1 to 5 wt.% in mass of the cement) on the mechanical and microstructural properties of cementitious composites has been characterised. The study showed that Fe3O4 nanoparticles acted as a filler which improved the microstructure of a cementitious composite and reduced its total porosity, thus increasing the density of the composite. The presence of nanomagnetite did not affect the main hydration products and the rate of cement hydration. In addition, the samples containing nanomagnetite exhibited compressive strength improvement (up to 20 %). The study showed that 3 wt.% of nano-Fe3O4 in the cementitious composite was the optimal amount to improve both its mechanical and microstructural properties.

  16. Vitrification of hazardous and radioactive wastes

    SciTech Connect

    Bickford, D.F.; Schumacher, R.

    1995-12-31

    Vitrification offers many attractive waste stabilization options. Versatility of waste compositions, as well as the inherent durability of a glass waste form, have made vitrification the treatment of choice for high-level radioactive wastes. Adapting the technology to other hazardous and radioactive waste streams will provide an environmentally acceptable solution to many of the waste challenges that face the public today. This document reviews various types and technologies involved in vitrification.

  17. Expensing options solves nothing.

    PubMed

    Sahlman, William A

    2002-12-01

    The use of stock options for executive compensation has become a lightning rod for public anger, and it's easy to see why. Many top executives grew hugely rich on the back of the gains they made on their options, profits they've been able to keep even as the value they were supposed to create disappeared. The supposed scam works like this: Current accounting regulations let companies ignore the cost of option grants on their income statements, so they can award valuable option packages without affecting reported earnings. Not charging the cost of the grants supposedly leads to overstated earnings, which purportedly translate into unrealistically high share prices, permitting top executives to realize big gains when they exercise their options. If an accounting anomaly is the problem, then the solution seems obvious: Write off executive share options against the current year's revenues. The trouble is, Sahlman writes, expensing option grants won't give us a more accurate view of earnings, won't add any information not already included in the financial statements, and won't even lead to equal treatment of different forms of executive pay. Far worse, expensing evades the real issue, which is whether compensation (options and other-wise) does what it's supposed to do--namely, help a company recruit, retain, and provide the right people with appropriate performance incentives. Any performance-based compensation system has the potential to encourage cheating. Only ethical management, sensible governance, adequate internal control systems, and comprehensive disclosure will save the investor from disaster. If, Sahlman warns, we pass laws that require the expensing of options, thinking that's fixed the fundamental flaws in corporate America's accounting, we will have missed a golden opportunity to focus on the much more extensive defects in the present system. PMID:12510541

  18. Supplemental Immobilization Cast Stone Technology Development and Waste Form Qualification Testing Plan

    SciTech Connect

    Westsik, Joseph H.; Serne, R. Jeffrey; Pierce, Eric M.; Cozzi, Alex; Chung, Chul-Woo; Swanberg, David J.

    2013-05-31

    The Hanford Tank Waste Treatment and Immobilization Plant (WTP) is being constructed to treat the 56 million gallons of radioactive waste stored in 177 underground tanks at the Hanford Site. The WTP includes a pretreatment facility to separate the wastes into high-level waste (HLW) and low-activity waste (LAW) fractions for vitrification and disposal. The LAW will be converted to glass for final disposal at the Integrated Disposal Facility (IDF). The pretreatment facility will have the capacity to separate all of the tank wastes into the HLW and LAW fractions, and the HLW Vitrification Facility will have the capacity to vitrify all of the HLW. However, a second immobilization facility will be needed for the expected volume of LAW requiring immobilization. A number of alternatives, including Cast Stone—a cementitious waste form—are being considered to provide the additional LAW immobilization capacity.

  19. Precipitation and Deposition of Aluminum Containing Species in Tank Wastes

    SciTech Connect

    Mattigod, Shas V.; Hobbs, David T.; Wang, L.; Dabbs, Daniel M.; Aksay, Ilhan A.

    2003-06-01

    Aluminum-containing phases represent the most prevalent solids that can appear or disappear during the processing of radioactive tank wastes. Processes such as sludge washing and leaching are designed to dissolve Al-containing phases and, thereby, minimize the volume of high-level waste glass required to encapsulate radioactive sludges. Unfortunately, waste-processing steps that include evaporation can involve solutions that are supersaturated with respect to cementitious aluminosilicates that result in unwanted precipitation and scale formation. Of all the constituents of tank waste, limited solubility cementitious aluminosilicates have the greatest potential for clogging pipes and transfer lines, fouling highly radioactive components such as ion exchangers, and completely shutting down processing operations. For instance, deposit buildup and clogged drain lines experienced during the tank waste volume-reduction process at Savannah River Site (SRS) required an evaporator to b e shut down in October 1999. The Waste Processing Technology Section (WPTS) of Westinghouse Savannah River Company (WSRC) at SRS is now collaborating with team members from Pacific Northwest National Laboratory (PNNL) to verify the thermodynamic stability of aluminosilicate compounds under waste tank conditions in an attempt to solve the deposition and clogging problems. The primary goals of this study are to understand the (1) the major factors controlling precipitation, heterogeneous nucleation and growth phenomena, of relatively insoluble aluminosilicates, (2) role of organics for inhibiting aluminosilicate formation, and (3) to develop a predictive tool to control precipitation, scale formation, and cementation under tank waste processing conditions. The results obtained from this will provide crucial information for (1) avoiding problematical sludge processing steps, and (2) identifying and developing effective technologies to process retrieved sludges and supernatants before ultimate

  20. Precipitation and Deposition of Aluminum Containing Species in Tank Wastes

    SciTech Connect

    Mattigod, Shas V.; Hobbs, David T.; Wang, L.; Dabbs, Daniel M.; Aksay, Ilhan A.

    2004-06-01

    Aluminum-containing phases represent the most prevalent solids that can appear or disappear during the processing of radioactive tank wastes. Processes such as sludge washing and leaching are designed to dissolve Al-containing phases and, thereby, minimize the volume of high-level waste glass required to encapsulate radioactive sludges. Unfortunately, waste-processing steps that include evaporation can involve solutions that are supersaturated with respect to cementitious aluminosilicates that result in unwanted precipitation and scale formation. Of all the constituents of tank waste, limited solubility cementitious aluminosilicates have the greatest potential for clogging pipes and transfer lines, fouling highly radioactive components such as ion exchangers, and completely shutting down processing operations. For instance, deposit buildup and clogged drain lines experienced during the tank waste volume-reduction process at Savannah River Site (SRS) required an evaporator to be shut down in October 1999. The Waste Processing Technology Section (WPTS) of Westinghouse Savannah River Company (WSRC) at SRS is now collaborating with team members from Pacific Northwest National Laboratory (PNNL) to verify the thermodynamic stability of aluminosilicate compounds under waste tank conditions in an attempt to solve the deposition and clogging problems. The primary goals of this study are to understand the (1) the major factors controlling precipitation, heterogeneous nucleation and growth phenomena, of relatively insoluble aluminosilicates, (2) role of organics for inhibiting aluminosilicate formation, and (3) to develop a predictive tool to control precipitation, scale formation, and cementation under tank waste processing conditions. The results obtained from this will provide crucial information for (1) avoiding problematical sludge processing steps, and (2) identifying and developing effective technologies to process retrieved sludges and supernatants before ultimate

  1. Porphyria Treatment Options

    MedlinePlus

    ... only. For treatment options for Porphyria Cutanea Tarda (PCT) , Congenital Erythropoietic Protoporphyria (CEP) and Hepatoerythropoietic Porphyria (HEP) ... Contact Us About Porphyria AIP VP HCP ADP PCT EPP CEP HEP Diet and Nutrition History of ...

  2. Yale's Tuition Postponement Option

    ERIC Educational Resources Information Center

    Curran, William E.

    1973-01-01

    Discusses Yale's Tuition Postponement Option which bases a student's repayment obligation on the student's future income. Under this system, some students will pay Yale less than the amounts they postponed plus interest and some will pay more. (JF)

  3. Space disposal of nuclear wastes

    NASA Technical Reports Server (NTRS)

    Priest, C. C.; Nixon, R. F.; Rice, E. E.

    1980-01-01

    The DOE has been studying several options for nuclear waste disposal, among them space disposal, which NASA has been assessing. Attention is given to space disposal destinations noting that a circular heliocentric orbit about halfway between Earth and Venus is the reference option in space disposal studies. Discussion also covers the waste form, showing that parameters to be considered include high waste loading, high thermal conductivity, thermochemical stability, resistance to leaching, fabrication, resistance to oxidation and to thermal shock. Finally, the Space Shuttle nuclear waste disposal mission profile is presented.

  4. Characterization of phosphate/sulfate waste grout cores

    SciTech Connect

    Martin, P.F.C.; Lokken, R.O.

    1993-09-01

    As part of efforts to clean up federal production sites, the U.S. Department of Energy (DOE) is treating selected low-level liquid wastes by incorporating them into cementitious waste forms. At the Hanford Site, low-level radioactive liquid wastes will be mixed with a blend of Portland cement, fly ash, clays, and other ingredients in a continuous process at the Grout Treatment Facility (GTF). The resulting grout slurry will be pumped to lined, underground concrete vaults where the grout will harden, thereby immobilizing contaminants. Physical property measurements and American Nuclear Society (ANS) 16.1 leach tests have been completed on 45 samples obtained from five cores from the phosphate/sulfate waste (PSW) grout vault. A summary of the compressive strength, bulk density, and sonic velocity data is compared with data from other PSW grout samples. Results of moisture content, thermal conductivity, and the leaching of aluminium, calcium, sodium, sulfate, cobalt-60, and cesium-137 are given.

  5. Characteristics of high temperature cementitious lost-circulation control materials for geothermal wells

    SciTech Connect

    Sugama, T.; Kukacka, L.E.; Galen, B.G.; Milestone, N.B.

    1986-01-01

    Materials systems have been formulated for the in situ conversion of water-based bentonite drilling fluids into cementitious lost-circulation control materials (CLCM) for use in geothermal wells at temperatures up to 300/sup 0/C. The formulations consist of a cement hardener, a borax admixture, and a fiber glass bridging material which are added to the bentonite fluids. Evaluations of the properties of the slurry and the cured CLCMS revealed that the ions supplied by dissociation of the borax in the CLCM slurry acted to suppress the bentonite hydration and retarded the hardening rate of the cement at elevated temperatures. The CaO-SiO/sub 2/-H/sub 2/O (C-S-H) phases formed during curing of the CLCM play essential roles in improving the quality of the hardened CLCMs. It was observed that xonotlite-truscottite transformation resulted in strength reductions and increased water permeability. The plugging ability of fiber glass depends on the conentration and fiber size. The silicate ions dissolved by hot alkaline disintegration of the fiber glass were chemisorbed with Ca/sup 2 +/ ions from the cement and led to the precipitation of C-S-H compounds on the fiber surfaces, which improved bond strength at the matrix-fiber interfaces.

  6. Observing the setting and hardening of cementitious materials by X-ray dark-field radiography

    SciTech Connect

    Prade, F.; Chabior, M.; Malm, F.; Grosse, C.U.; Pfeiffer, F.

    2015-08-15

    Novel X-ray imaging methods expand conventional attenuation-based X-ray radiography by the phase- and the dark-field contrasts. While weakly absorbing structures in the specimen can be better visualized in phase contrast, the dark-field contrast provides information about morphological sub-pixel microstructures. Here we report an application of dark-field X-ray radiography for imaging the time-resolved setting process in fresh cement. Our results demonstrate that the microstructural changes within the cement result in a decreasing dark-field signal. We quantify this imaging signal with a time-dependent dark-field scatter coefficient and show its good correlation with the compressional wave velocity. We further present images based on a pixel-wise analysis of the scattering signal and a corresponding logistic fit. These images emphasize the benefit of dark-field imaging of cementitious materials as it provides two dimensional spatial information on the processes within the sample while other established testing techniques only provide information on the bulk average.

  7. Influence of the cementitious paste composition on the E-modulus and heat of hydration evolutions

    SciTech Connect

    Maia, Lino; Azenha, Miguel; Faria, Rui; Figueiras, Joaquim

    2011-08-15

    E-modulus and heat of hydration are features of cement-based materials that follow a rapid rate of change at early ages. This paper analyses the influence of the composition of cementitious pastes on these features by using two methods: (i) a novel technique for continuously monitoring the E-modulus of cement-based materials, based on evaluating the first resonant frequency of a composite beam containing the material under testing, and (ii) an isothermal calorimeter to determine the released heat of hydration. Seventeen mixes are tested, encompassing pastes with five w/c ratios, as well as different contents of limestone filler, fly ash, silica fume and metakaolin. The results permit the comparison of the E-modulus and heat of hydration sensitivities to mix composition changes, and to check possible relations between these features. This work also helps to establish the technique (i) as a non-destructive method for monitoring the E-modulus evolution in cement-based materials since casting.

  8. Semi-automatic classification of cementitious materials using scanning electron microscope images

    NASA Astrophysics Data System (ADS)

    Drumetz, L.; Dalla Mura, M.; Meulenyzer, S.; Lombard, S.; Chanussot, J.

    2015-04-01

    A new interactive approach for segmentation and classification of cementitious materials using Scanning Electron Microscope images is presented in this paper. It is based on the denoising of the data with the Block Matching 3D (BM3D) algorithm, Binary Partition Tree (BPT) segmentation and Support Vector Machines (SVM) classification. The latter two operations are both performed in an interactive way. The BPT provides a hierarchical representation of the spatial regions of the data and, after an appropriate pruning, it yields a segmentation map which can be improved by the user. SVMs are used to obtain a classification map of the image with which the user can interact to get better results. The interactivity is twofold: it allows the user to get a better segmentation by exploring the BPT structure, and to help the classifier to better discriminate the classes. This is performed by improving the representativity of the training set, adding new pixels from the segmented regions to the training samples. This approach performs similarly or better than methods currently used in an industrial environment. The validation is performed on several cement samples, both qualitatively by visual examination and quantitatively by the comparison of experimental results with theoretical values.

  9. Multi-scale roughness measurement of cementitious materials using different optical profilers and window resizing analysis

    NASA Astrophysics Data System (ADS)

    Montgomery, Paul C.; Salzenstein, Fabien; Gianto, Gianto; Apedo, Komla L.; Serres, Nicolas; Fond, Christophe; Feugeas, Françoise

    2015-05-01

    In the development of new eco-cements for ecologically friendly construction, the porosity, surface structure and chemical nature of the material can influence the bioreceptivity of the surface and the aptitude or not of environmental micro-organisms to form biofilms. Such films are the source of biocontamination that can lead to a degradation in the structural properties over time. Accurate measurement of surface roughness and topography are important to help in the understanding of this interaction. Optical profilers are well adapted to the quantifying of large surface roughness typical of cementitious materials, being more rapid and better able to cope with high roughness compared with stylus and near field probe techniques. But any given surface profiler typically has specific range limits in terms of axial and lateral resolution and field of view, resulting in different roughness values according to the type of optical profiler used. In the present work, unpolished and polished cement paste samples have been measured with two different systems, one using interference microscopy and the other, chromatic confocal sensing. Comparison of the results from both techniques using the method of window re-sizing, more commonly used in tribology, has been used for calculating the average roughness parameters at different scales. The initial results obtained show a successful overlap of the results for the unpolished samples and a slight separation for the polished samples. The validation of the measurements is demonstrated together with a revealing of differences in the measurements on different types of surfaces due to variations in instrument performance.

  10. Thermally conductive cementitious grouts for geothermal heat pumps. Progress report FY 1998

    SciTech Connect

    Allan, M.L.; Philippacopoulos, A.J.

    1998-11-01

    Research commenced in FY 97 to determine the suitability of superplasticized cement-sand grouts for backfilling vertical boreholes used with geothermal heat pump (GHP) systems. The overall objectives were to develop, evaluate and demonstrate cementitious grouts that could reduce the required bore length and improve the performance of GHPs. This report summarizes the accomplishments in FY 98. The developed thermally conductive grout consists of cement, water, a particular grade of silica sand, superplasticizer and a small amount of bentonite. While the primary function of the grout is to facilitate heat transfer between the U-loop and surrounding formation, it is also essential that the grout act as an effective borehole sealant. Two types of permeability (hydraulic conductivity) tests was conducted to evaluate the sealing performance of the cement-sand grout. Additional properties of the proposed grout that were investigated include bleeding, shrinkage, bond strength, freeze-thaw durability, compressive, flexural and tensile strengths, elastic modulus, Poisson`s ratio and ultrasonic pulse velocity.

  11. Development of leachate test for delayed ettringite formation potential in cementitious materials

    NASA Astrophysics Data System (ADS)

    France-Mensah, Jojo

    Delayed Ettringite Formation (DEF) has been known to be the cause of expansion and cracking at latter ages in concrete that has been heat cured at temperatures around 70 degree Celsius or above. Currently, the only method available for measuring DEF-related physical expansion in concrete can sometimes take over a year to yield relevant results. A leachate method was proposed as a means of taking advantage of the release and solubility of the adsorbed ions (e.g., calcium, sulfates and aluminates) and alkali ions (e.g., sodium and potassium) in the pore solution after heat curing of the cement paste matrix. These ions, known to contribute to DEF, were leached out of concrete into the leaching solution. The results of the leachate test were correlated to physical expansion data of similar samples from an earlier study. The aim of this research is to apply this knowledge to develop an accelerated leachate test method for identifying the potential for DEF in cementitious materials in a shorter time than the existing method. The objectives of this research are: (1) to identify the ion(s) through leaching that is/are the controlling factors in predicting the rate of expansion and overall expansion of mortar; (2) to identify the ion(s) that is/are responsible for the lag time or age of deleterious expansion through DEF; and (3) to investigate the effect of heat curing on the overall, rate of, and age (time) of expansion.

  12. Microstructural changes in a cementitious membrane due to the application of a DC electric field.

    PubMed

    Covelo, Alba; Diaz, Belen; Freire, Lorena; Novoa, X Ramon; Perez, M Consuelo

    2008-07-01

    The use of electromigration techniques to accelerate chloride ions motion is commonly employed to characterise the permeability of cementitious samples to chlorides, a relevant parameter in reinforced concrete corrosion. This paper is devoted to the study of microstructure's changes occurring in mortar samples when submitted to natural diffusion and migration experiments. The application of an electric field reduces testing time in about one order of magnitude with respect to natural diffusion experiments. Nevertheless, the final sample's microstructure differs in both tests. Impedance Spectroscopy is employed for real time monitoring of microstructural changes. During migration experiments the global impedance undergoes important increase in shorter period of time compared to natural diffusion tests. So, the forced motion of ions through the concrete membrane induces significant variations in the porous structure, as confirmed by Mercury Intrusion Porosimetry. After migration experiments, an important increase in the capillary pore size (10-100 nm) was detected. Conversely, no relevant variations are found after natural diffusion tests. Results presented in this work cast doubt on the significance of diffusion coefficient values obtained under accelerated conditions. PMID:18569312

  13. Cementitious binders from activated stainless steel refining slag and the effect of alkali solutions.

    PubMed

    Salman, Muhammad; Cizer, Özlem; Pontikes, Yiannis; Snellings, Ruben; Vandewalle, Lucie; Blanpain, Bart; Van Balen, Koen

    2015-04-01

    With an aim of producing high value cementitious binder, stainless steel refining slag containing a high amount of CaO in γ-dicalcium silicate form was activated with NaOH and Na-silicate as well as KOH and K-silicate solutions, followed by steam curing at 80 °C. Higher levels of alkali-silicate in the activating solution resulted in higher cumulative heat suggesting accelerated reaction kinetics. With respect to compressive strength, higher levels of alkali silicate resulted in higher strength and the mortars with Na activator were found to have higher early strength than the ones with K activator. The long term strength was found to be similar, regardless of the alkali metal. Thermogravimetric, QXRD and FTIR analyses showed an increase in the amount of reaction products (C-S-H type) over time, further confirming the reactivity of the crystalline slag. Batch leaching results showed lower leaching of heavy metals and metalloids with K activator compared to the Na activator. These results demonstrate that the alkali type and the ratio of hydroxide to silicates have a significant impact on the hydration and mechanical strength development of the stainless steel slag. The above findings can aid in the recycling and valorization of these type of slags which otherwise end up landfilled. PMID:25577317

  14. Effect of different supplementary cementitious materials on mechanical properties of high performance concrete

    SciTech Connect

    Khatri, R.P.; Sirivivatnanon, V. . Div. of Building, Construction and Engineering); Gross, W. . Readymix Group)

    1995-01-01

    High performance concrete prepared from general purpose (GP) portland cement and various supplementary cementitious materials are increasingly finding their use in construction worldwide. This study was undertaken to compare mechanical properties as well as fresh concrete properties of concretes containing silica fume, ground granulated blast furnace slag (slag), fly ash and GP portland cement. The aim of the study was to enable evaluation of the suitability of a particular binder system for an application based on fresh concrete properties and mechanical properties. Concrete mixes were prepared with GP portland cement, high slag cement and slag cement, and also mixes were prepared with the addition of silica fume and fly ash. The work focused on concrete mixes having a fixed water/binder ratio of 0.35 and a constant total binder content of 430 kg/m[sup 3]. Apart from measuring fresh concrete properties, the mechanical properties evaluated were development of compressive strength, flexural strength, elastic modulus, and strain due to creep and drying shrinkage. Results indicated that the addition of silica fume to GP portland cement concrete marginally decreased the workability of the concrete but significantly improved the mechanical properties. However, the effect of addition of silica fume to high slag cement concrete was less pronounced.

  15. New waste based clinkers: Belite and lime formulations

    SciTech Connect

    Raupp-Pereira, Fabiano; Ball, Richard James Rocha, Joao; Labrincha, Joao A.; Allen, Geoffrey C.

    2008-04-15

    This work describes the formulation of new belite-based (CR2) and lime-based (CR3) cementitious materials derived from industrial wastes, such as sludges (generated in the Al-anodising and surface coating industrial processes, potable water filtration/cleaning operations and in marble sawing processes) and foundry sand. Powder mixtures were prepared and fired at different temperatures. For comparison, similar formulations were prepared with pre-treated and commercially available natural raw materials and processed in similar conditions. The thermal process was followed by differential scanning calorimetry (DSC) and high-temperature powder X-ray diffraction (HT-XRD) studies. The CR2 clinker was found to contain belite as the main cementitious phase, the main polymorph being identified by NMR. The CR3 clinker contained common cementitious phases, such as C{sub 3}A and C{sub 3}S, but free lime and calcium aluminium oxide sulphates were also identified by high temperature XRD and NMR. Then the corresponding cement was prepared and the evolution of the mechanical strength with time was evaluated. The lime-based cement obtained from wastes shows a stronger hardening character than the standard material, which tends to show dusting phenomena due to the presence of a reasonable amount of free lime (as the result of its expansive reaction with ambient moisture). Some fluxing impurities (e.g. alkalis) present in the waste materials improve the overall reactivity of the mixture and induces the combination of the lime in CR3. Raman, XPS and FIB techniques were used to fully characterise the aged cements.

  16. Low-level waste disposal - Grout issue and alternative waste form technology

    SciTech Connect

    Epstein, J.L.; Westski, J.H. Jr.

    1993-02-01

    Based on the Record of Decision (1) for the Hanford Defense Waste Environmental Impact Statement (HDW-EIS) (2), the US Department of Energy (DOE) is planning to dispose of the low-level fraction of double-shell tank (DST) waste by solidifying the liquid waste as a cement-based grout placed in near-surface, reinforced, lined concrete vaults at the Hanford Site. In 1989, the Hanford Grout Disposal Program (HGDP) completed a full-scale demonstration campaign by successfully grouting 3,800 cubic meters (1 million gallons) of low radioactivity, nonhazardous, phosphate/sulfate waste (PSW), mainly decontamination solution from N Reactor. The HGDP is now preparing for restart of the facility to grout a higher level activity, mixed waste double-shell slurry feed (DSSF). This greater radionuclide and hazardous waste content has resulted in a number of issues confronting the disposal system and the program. This paper will present a brief summary of the Grout Treatment Facility`s components and features and will provide a status of the HGDP, concentrating on the major issues and challenges resulting from the higher radionuclide and hazardous content of the waste. The following major issues will be discussed: Formulation (cementitious mix) development; the Performance Assessment (PA) (3) to show compliance of the disposal system to long-term environmental protection objectives; and the impacts of grouting on waste volume projections and tank space needs.

  17. Stabilization Using Phosphate Bonded Ceramics. Salt Containing Mixed Waste Treatment. Mixed Waste Focus Area. OST Reference No. 117

    SciTech Connect

    None, None

    1999-09-01

    Throughout the Department of Energy (DOE) complex there are large inventories of homogeneous mixed waste solids, such as wastewater treatment residues, fly ashes, and sludges that contain relatively high concentrations (greater than 15% by weight) of salts. The inherent solubility of salts (e.g., nitrates, chlorides, and sulfates) makes traditional treatment of these waste streams difficult, expensive, and challenging. One alternative is low-temperature stabilization by chemically bonded phosphate ceramics (CBPCs). The process involves reacting magnesium oxide with monopotassium phosphate with the salt waste to produce a dense monolith. The ceramic makes a strong environmental barrier, and the metals are converted to insoluble, low-leaching phosphate salts. The process has been tested on a variety of surrogates and actual mixed waste streams, including soils, wastewater, flyashes, and crushed debris. It has also been demonstrated at scales ranging from 5 to 55 gallons. In some applications, the CBPC technology provides higher waste loadings and a more durable salt waste form than the baseline method of cementitious grouting. Waste form test specimens were subjected to a variety of performance tests. Results of waste form performance testing concluded that CBPC forms made with salt wastes meet or exceed both RCRA and recommended Nuclear Regulatory Commission (NRC) low-level waste (LLW) disposal criteria. Application of a polymer coating to the CBPC may decrease the leaching of salt anions, but continued waste form evaluations are needed to fully assess the deteriorating effects of this leaching, if any, over time.

  18. Lighting Options for Homes.

    SciTech Connect

    Baker, W.S.

    1991-04-01

    This report covers many aspects of various lighting options for homes. Types of light sources described include natural light, artificial light, incandescent lamps, fluorescent lamps, and high intensity discharge lamps. A light source selection guide gives the physical characteristics of these, design considerations, and common applications. Color, strategies for efficient lighting, and types of lighting are discussed. There is one section giving tips for various situations in specific rooms. Rooms and types of fixtures are shown on a matrix with watts saved by using the recommended type lighting for that room and room location. A major emphasis of this report is saving energy by utilizing the most suitable, recommended lighting option. (BN)

  19. Thermal test options

    SciTech Connect

    Koski, J.A.; Keltner, N.R.; Sobolik, K.B.

    1993-02-01

    Shipping containers for radioactive materials must be qualified to meet a thermal accident environment specified in regulations, such at Title 10, Code of Federal Regulations, Part 71. Aimed primarily at the shipping container design, this report discusses the thermal testing options available for meeting the regulatory requirements, and states the advantages and disadvantages of each approach. The principal options considered are testing with radiant heat, furnaces, and open pool fires. The report also identifies some of the facilities available and current contacts. Finally, the report makes some recommendations on the appropriate use of these different testing methods.

  20. New methods to quantify the cracking performance of cementitious systems made with internal curing

    NASA Astrophysics Data System (ADS)

    Schlitter, John L.

    The use of high performance concretes that utilize low water-cement ratios have been promoted for use in infrastructure based on their potential to increase durability and service life because they are stronger and less porous. Unfortunately, these benefits are not always realized due to the susceptibility of high performance concrete to undergo early age cracking caused by shrinkage. This problem is widespread and effects federal, state, and local budgets that must maintain or replace deterioration caused by cracking. As a result, methods to reduce or eliminate early age shrinkage cracking have been investigated. Internal curing is one such method in which a prewetted lightweight sand is incorporated into the concrete mixture to provide internal water as the concrete cures. This action can significantly reduce or eliminate shrinkage and in some cases causes a beneficial early age expansion. Standard laboratory tests have been developed to quantify the shrinkage cracking potential of concrete. Unfortunately, many of these tests may not be appropriate for use with internally cured mixtures and only provide limited amounts of information. Most standard tests are not designed to capture the expansive behavior of internally cured mixtures. This thesis describes the design and implementation of two new testing devices that overcome the limitations of current standards. The first device discussed in this thesis is called the dual ring. The dual ring is a testing device that quantifies the early age restrained shrinkage performance of cementitious mixtures. The design of the dual ring is based on the current ASTM C 1581-04 standard test which utilizes one steel ring to restrain a cementitious specimen. The dual ring overcomes two important limitations of the standard test. First, the standard single ring test cannot restrain the expansion that takes place at early ages which is not representative of field conditions. The dual ring incorporates a second restraining ring

  1. ARSENIC TREATMENT OPTIONS

    EPA Science Inventory

    The PPT presentation will provide information on the drinking water treatment options for small utilities to remove arsenic from ground water. The discussion will include information on the EPA BAT listed processes and on some of the newer technologies, such as the iron based ad...

  2. Yale Tuition Postponement Option.

    ERIC Educational Resources Information Center

    Yale Univ., New Haven, CT. Office of the President.

    This paper offers a detailed explanation of Yale University's tuition postponement option. The purposes of the Plan are: (1) to enable students to defer part of the expense of education; (2) to enable students to contribute to the support of the University in approximate proportion to their ability to do so and to the economic benefit they have…

  3. Idaho's Energy Options

    SciTech Connect

    Robert M. Neilson

    2006-03-01

    This report, developed by the Idaho National Laboratory, is provided as an introduction to and an update of the status of technologies for the generation and use of energy. Its purpose is to provide information useful for identifying and evaluating Idaho’s energy options, and for developing and implementing Idaho’s energy direction and policies.

  4. CFB repowering options

    SciTech Connect

    Gittinger, J.

    1996-12-31

    Circulating fluidized bed CFB repowering options are summarized. The following topics are discussed: why repower with CFB technology; advantages of repowering; two forms of of repowering; B and N`s internal recirculation CFB; space-saving design features; cost-saving design features; Ukrainian repowering project; and candidates for repowering.

  5. Our Energy Options.

    ERIC Educational Resources Information Center

    Meyers, Paul A.; Witt, Frank C.

    Presented is an analysis of alternatives available to the United States in dealing with energy problems. Options explained and evaluated include coal, solar, hydroelectric, nuclear, geothermal, wind, biomass, and energy conservation. The booklet is part of Project APEC (America's Possible Energy Choices), a nationally validated Title IVc project…

  6. Postsecondary Enrollment Options Programs.

    ERIC Educational Resources Information Center

    Michelau, Demaree K.

    2001-01-01

    Many states are beginning to notice discontinuities in policy between the K-12 and higher education systems. One approach to easing the high school to college transition is to establish postsecondary enrollment options (PSEO) programs. Currently, 32 states have laws or recently have passed legislation to establish and govern PSEO programs. The…

  7. Options in Suicidal Crisis

    ERIC Educational Resources Information Center

    Steenland, Roger

    1973-01-01

    This article briefly outlines possible causes for the prevalence of suicide attempts among college students and then discusses various options for handling such crises: whether to notify the students' closest relatives, whether to obtain medical evaluation and treatment (as opposed to psychological counseling), and whether to allow the student to…

  8. Career Options in Chemistry.

    ERIC Educational Resources Information Center

    Belloli, Robert C.

    1985-01-01

    Describes a credit/no credit course which focuses on career options in chemistry. The course (consisting of 15 one-hour seminar-type sessions) includes guest speakers for several sessions and an emphasis (in introductory sessions) on graduate school in chemistry, the chemical industry, resumes, and interviews. Also briefly describes an internship…

  9. Alternative Education Options.

    ERIC Educational Resources Information Center

    Little (Arthur D.), Inc., Washington, DC.

    This guide deals with various areas of alternative education programs, including current practices and different options available to school and community personnel. Steps are outlined to assess present educational settings, design new programs, select the participants, and implement and evaluate the new program. The first appendix contains…

  10. Perspectives on sustainable waste management.

    PubMed

    Castaldi, Marco J

    2014-01-01

    Sustainable waste management is a goal that all societies must strive to maintain. Currently nearly 80% of global wastes are sent to landfill, with a significant amount lacking proper design or containment. The increased attention to environmental impacts of human activities and the increasing demand for energy and materials have resulted in a new perspective on waste streams. Use of waste streams for energy and materials recovery is becoming more prevalent, especially in developed regions of the world, such as Europe, the United States, and Japan. Although currently these efforts have a small impact on waste disposal, use of waste streams to extract value very likely will increase as society becomes more aware of the options available. This review presents an overview of waste management with a focus on following an expanded waste hierarchy to extract value specifically from municipal solid waste streams. PMID:24910921

  11. Preliminary seal design evaluation for the Waste Isolation Pilot Plant

    SciTech Connect

    Stormont, J C

    1988-03-01

    This report presents a preliminary evaluation of design concepts for the eventual sealing of the shafts, drifts, and boreholes at the Waste Isolation Pilot Plant Facility. The purpose of the seal systems is to limit the flow of water into, through, and out of the repository. The principal design strategy involves the consolidation of crushed or granular salt in response to the closure of the excavations in salt. Other candidate seal materials are bentonite, cementitious mixtures, and possibly asphalt. Results from in situ experiments and modeling studies, as well as laboratory materials testing and related industrial experience, are used to develop seal designs for shafts, waste storage panel entryways, non-waste containing drifts, and boreholes. Key elements of the ongoing experimental program are identified. 112 refs., 25 figs., 1 tab.

  12. MEDICAL AND INSTITUTIONAL WASTE INCINERATION: REGULATIONS, MANAGEMENT, TECHNOLOGY, EMISSIONS, AND OPERATION

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) initiated a series of seminars to assist those responsible for managing medical waste in understanding the applicable regulations; developing waste management plans; selecting appropriate waste management options, including incinerat...

  13. Osteoporosis: Therapeutic Options.

    PubMed

    Ivanova, Stefka; Vasileva, Liliya; Ivanova, Stanislava; Peikova, Lily; Obreshkova, Danka

    2016-01-01

    The definition of osteoporosis was originally formulated at a conference of the World Health Organization (WHO) in 1993 as 'a systemic skeletal disease characterized by decreased bone mass and altered micro-architecture of bone tissue, leading to enhanced bone fragility and risk of fractures'. Osteoporosis is characterized by low bone mineral density (BMD) and loss of the structural and bio-mechanical properties that are required to maintain bone homeostasis. This review aims to address the currently available options in prevention and treatment of osteoporosis. Management of osteoporosis includes non-pharmacological treatment - diet rich of calcium and vitamin D, healthy lifestyle, proper exercise plan, and pharmacological therapy. Combination of non-pharmacological and pharmacological treatment options have to be considered for prevention of osteoporosis and minimization of the risk of fractures. Given the heterogeneity of osteoporosis syndrome and lack of significant number of comparative studies, the choice of a pharmacological agents should be individualized. PMID:27180344

  14. Information technology financing options.

    PubMed

    Rai, D

    1996-01-01

    Healthcare executives facing the challenges of delivering quality care and controlling costs must consider the role information technology systems can play in meeting those challenges. To make the best use of information system expenditures, organizations must carefully plan how to finance system acquisitions. Some options that should be considered are paying cash, financing, financing "soft" costs, leasing, credit warehousing and early acceptance financing, and tax-exempt and conduit financing. PMID:10154097

  15. In situ electrochemical characterization of grouted radioactive waste

    SciTech Connect

    Gu, Jingyan; Shen, Wu-Mian; Tomkiewicz, Micha; Kruger, A.A.

    1993-04-01

    At the Hanford Site, twenty-eight double-shell tanks (DST) and one hundred and forty nine single-shell tanks (SST) are used for storage of radioactive liquid and sludge wastes and sat cake. A fundamental goal of the Westinghouse Hanford Company is to end the current storage practice for liquid wastes and to permanently dispose of the waste. The Hanford Defense Waste Environmental Impact Statement and subsequent record of decision has identified a cement-based waste form for disposal of DST low-level liquid waste. The low level radioactive fractions of these wastes will be immobilized in a cementitious grout at the Hanford Grout Processing Facility and disposed of in concrete vaults of the Grout Disposal Facility. Prior to closing each vault, postcuring verification will show that the final product meets the performance requirements. Any long term disposal system of radioactive waste will require monitoring to warn against structural deterioration and/or leach of the radioactive or hazardous components into the environment. We are investigating the possibility of monitoring the degree of immobilization of the waste by embedding a grid of long-lasting electrodes in grout. This work describes our ongoing attempts to understand the physics and chemistry of charge carriers in the grout under various load conditions.

  16. Novel operative treatment options.

    PubMed

    Ricketts, D N J; Pitts, N B

    2009-01-01

    There are an increasing number of more novel options available for operative intervention. This chapter outlines a series of operative treatment options which are available to the modern clinician to select from once a decision has been made to treat a carious lesion operatively. A series of novel methods of caries removal have been described; including chemomechanical caries removal, air abrasion, sono-abrasion, polymer rotary burs and lasers. There are also novel approaches to ensure complete caries removal and novel approaches for the management of deep caries. A novel question increasingly asked by clinicians is: does all the caries need to be removed? Operative management options here include: therapeutic fissure sealants, ultraconservative caries removal, stepwise excavation and the Hall technique. In conclusion, there is now a growing wealth of evidence that questions the traditional methods of caries removal and restoring the tooth. In parallel, there is a growing movement exploring the merits of therapeutically sealing caries into the tooth. This philosophy is alien to many of today's dentists and, until further randomized controlled trials are carried out in primary care, prudent caution must be exercised with this promising approach. Research is required into techniques which will allow monitoring of sealed caries to detect any rare, but insidious, failures. These novel techniques are an alternative way of managing the later stages of the caries process from a sounder biological basis and have marked potential benefits to patients from treatment, pain and outcome perspectives. PMID:19494685

  17. The safeguards options study

    SciTech Connect

    Hakkila, E.A.; Mullen, M.F.; Olinger, C.T.; Stanbro, W.D.; Olsen, A.P.; Roche, C.T.; Rudolph, R.R.; Bieber, A.M.; Lemley, J.; Filby, E.

    1995-04-01

    The Safeguards Options Study was initiated to aid the International Safeguards Division (ISD) of the DOE Office of Arms Control and Nonproliferation in developing its programs in enhanced international safeguards. The goal was to provide a technical basis for the ISD program in this area. The Safeguards Options Study has been a cooperative effort among ten organizations. These are Argonne National Laboratory, Brookhaven National Laboratory, Idaho National Engineering Laboratory, Lawrence Livermore National Laboratory, Los Alamos National Laboratory, Mound Laboratory, Oak Ridge National Laboratory, Pacific Northwest Laboratories, Sandia National Laboratories, and Special Technologies Laboratory. Much of the Motivation for the Safeguards Options Study is the recognition after the Iraq experience that there are deficiencies in the present approach to international safeguards. While under International Atomic Energy Agency (IAEA) safeguards at their declared facilities, Iraq was able to develop a significant weapons program without being noticed. This is because negotiated safeguards only applied at declared sites. Even so, their nuclear weapons program clearly conflicted with Iraq`s obligations under the Nuclear Nonproliferation Treaty (NPT) as a nonnuclear weapon state.

  18. The Option for Survival

    ERIC Educational Resources Information Center

    Berry, R. Stephen

    1971-01-01

    Suggests formula for survival that takes a thermodynamic view which holds that we must recycle waste while the thermodynamic potential still is moderately high. Otherwise they are lost, as helium is lost when it leaves Earth's atmosphere and goes into space. The idea that the Earth is a closed system is a myth; it collapses each time we put our…

  19. Formulation and Analysis of Compliant Grouted Waste Forms for SHINE Waste Streams

    SciTech Connect

    Ebert, William; Pereira, Candido; Heltemes, Thad A.; Youker, Amanda; Makarashvili, Vakhtang; Vandegrift, George F.

    2014-01-01

    Optional grouted waste forms were formulated for waste streams generated during the production of 99Mo to be compliant with low-level radioactive waste regulations. The amounts and dose rates of the various waste form materials that would be generated annually were estimated and used to determine the effects of various waste processing options, such as the of number irradiation cycles between uranium recovery operations, different combinations of waste streams, and removal of Pu, Cs, and Sr from waste streams for separate disposition (which is not evaluated in this report). These calculations indicate that Class C-compliant grouted waste forms can be produced for all waste streams. More frequent uranium recovery results in the generation of more chemical waste, but this is balanced by the fact that waste forms for those waste streams can accommodate higher waste loadings, such that similar amounts of grouted waste forms are required regardless of the recovery schedule. Similar amounts of grouted waste form are likewise needed for the individual and combined waste streams. Removing Pu, Cs, and Sr from waste streams lowers the waste form dose significantly at times beyond about 1 year after irradiation, which may benefit handling and transport. Although these calculations should be revised after experimentally optimizing the grout formulations and waste loadings, they provide initial guidance for process development.

  20. Y-12 Waste Management Division Process Waste Assessment (PWA) report

    SciTech Connect

    Not Available

    1992-01-01

    The Process Waste Assessment (PWA) methodology used by the Martin Marietta Energy Systems, Inc. (Energy Systems) Y-12 Waste Management Division (WMD) was based on the US Department of Energy (DOE) Model Process Waste Assessment Plan, which in turn, was based on the US Environmental Protection Agency, (US EPA) Waste Minimization Opportunity Assessment Manual but incorporated modifications suggested by various DOE production facilities. The DOE PWA plan methodology was slightly modified to meet the differing needs of WMD because the model was directed toward production operations versus waste treatment, storage, and disposal operations. The objective of this PWA was to compile information about the WMD operations and processes that transport, treat, store, and dispose of waste streams generated by other Y-12 organizations and WMD. Data were also collected on WMD operating procedures and WMD waste streams as well as other Y-12 organizations' waste streams managed. The assessment consisted of five primary steps: organization of the WMD PWA Team and subteams, assessment of WMD operations and waste streams, development and evaluation of waste minimization options, compilation, review, and publication of the PWA report and supporting data, and implementation of waste minimization options.

  1. Y-12 Waste Management Division Process Waste Assessment (PWA) report

    SciTech Connect

    Not Available

    1992-01-01

    The Process Waste Assessment (PWA) methodology used by the Martin Marietta Energy Systems, Inc. (Energy Systems) Y-12 Waste Management Division (WMD) was based on the US Department of Energy (DOE) Model Process Waste Assessment Plan, which in turn, was based on the US Environmental Protection Agency, (US EPA) Waste Minimization Opportunity Assessment Manual but incorporated modifications suggested by various DOE production facilities. The DOE PWA plan methodology was slightly modified to meet the differing needs of WMD because the model was directed toward production operations versus waste treatment, storage, and disposal operations. The objective of this PWA was to compile information about the WMD operations and processes that transport, treat, store, and dispose of waste streams generated by other Y-12 organizations and WMD. Data were also collected on WMD operating procedures and WMD waste streams as well as other Y-12 organizations` waste streams managed. The assessment consisted of five primary steps: organization of the WMD PWA Team and subteams, assessment of WMD operations and waste streams, development and evaluation of waste minimization options, compilation, review, and publication of the PWA report and supporting data, and implementation of waste minimization options.

  2. USE OF CEMENTITIOUS MATERIALS FOR SRS REACTOR FACILITY IN-SITU DECOMMISSIONING - 11620

    SciTech Connect

    Langton, C.; Stefanko, D.; Serrato, M.; Blankenship, J.; Griffin, W.; Waymer, J.; Matheny, D.; Singh, D.

    2010-12-07

    The United States Department of Energy (US DOE) concept for facility in-situ decommissioning (ISD) is to physically stabilize and isolate in tact, structurally sound facilities that are no longer needed for their original purpose of, i.e., producing (reactor facilities), processing (isotope separation facilities) or storing radioactive materials. The Savannah River Site 105-P and 105-R Reactor Facility ISD requires about 250,000 cubic yards of grout to fill the below grade structure. The fills are designed to prevent subsidence, reduce water infiltration, and isolate contaminated materials. This work is being performed as a Comprehensive Environmental Response, Compensations and Liability Act (CERCLA) action and is part of the overall soil and groundwater completion projects for P- and R-Areas. Cementitious materials were designed for the following applications: (1) Below grade massive voids/rooms: Portland cement-based structural flowable fills for - Bulk filling, Restricted placement and Underwater placement. (2) Special below grade applications for reduced load bearing capacity needs: Cellular portland cement lightweight fill (3) Reactor vessel fills that are compatible with reactive metal (aluminum metal) components in the reactor vessels: Calcium sulfoaluminate flowable fill, and Magnesium potassium phosphate flowable fill. (4) Caps to prevent water infiltration and intrusion into areas with the highest levels of radionuclides: Portland cement based shrinkage compensating concrete. A system engineering approach was used to identify functions and requirements of the fill and capping materials. Laboratory testing was performed to identify candidate formulations and develop final design mixes. Scale-up testing was performed to verify material production and placement as well as fresh and cured properties. The 105-P and 105-R ISD projects are currently in progress and are expected to be complete in 2012. The focus of this paper is to describe the (1) grout mixes

  3. Self-decomposable Fibrous Bridging Additives for Temporary Cementitious Fracture Sealers in EGS Wells

    SciTech Connect

    Sugama T.; Pyatina, T.; Gill, S.; Kisslinger, K.; Iverson, B.; Bour, D.

    2012-11-01

    This study evaluates compatibility of a self-degradable temporary fracture sealer with the drilling mud and plugging and self-degrading performance of different fibers to be used in combination with the sealer. The sodium silicate-activated slag/Class C fly ash (SSASC) cementitious sealer must plug fractures at 85oC to allow continuous well drilling and it must degrade and leave the fractures open for water at later times when exposed to temperatures above 200oC. The sealer showed good compatibility with the mud. Even the blend of 80/20 vol.% of sealer/mud reached a compressive strength of more than 2000 psi set as one of the material criteria, mostly due to the additional activation of the slag and Class C fly ash by the alkaline ingredient present in the drilling fluid. In contrast, the drilling fluid was detrimental to the compressive strength development in conventional Class G well cement, so that it failed to meet this criterion. Among several organic fibers tested both polyvinyl alcohol (PVA)-and nylon-based fibers showed adequate plugging of the sealer in slot nozzles of 1-in. wide x 6-in. long x 0.08 in. and 0.24 in. high under pressures up to 700 psi. PVA fibers displayed better compressive toughness and self-degrading properties than nylon. The compressive toughness of sealers made by adding 1.0 wt% 6 mm-length PVA and 0.5 wt% 19 mm-length PVA was 9.5-fold higher than that of a non-bridged sealer. One factor governing the development of such high toughness was an excellent adherence of PVA to the SSASC cement. The alkali-catalyzed self-decomposition of PVA at 200°C led to the morphological transformation of the material from a fibrous structure to a microscale flake-like structure that helped the desirable conversion of the sealer into small fragments. In contrast, nylon’s decomposition provided a reticular network structure in the self-degraded sealer resulting in bigger fragments compared against the sealer with PVA. The PVA fiber has a high

  4. Decision and systems analysis for underground storage tank waste retrieval systems and tank waste remediation system

    SciTech Connect

    Bitz, D.A.; Berry, D.L.; Jardine, L.J.

    1994-03-01

    Hanford`s underground tanks (USTs) pose one of the most challenging hazardous and radioactive waste problems for the Department of Energy (DOE). Numerous schemes have been proposed for removing the waste from the USTs, but the technology options for doing this are largely unproven. To help assess the options, an Independent Review Group (IRG) was established to conduct a broad review of retrieval systems and the tank waste remediation system. The IRG consisted of the authors of this report.

  5. Achilles Tendinosis: Treatment Options

    PubMed Central

    Lopez, Roberto Gabriel L.

    2015-01-01

    Athletes usually complain of an ongoing or chronic pain over the Achilles tendon, but recently even non-athletes are experiencing the same kind of pain which affects their daily activities. Achilles tendinosis refers to a degenerative process of the tendon without histologic or clinical signs of intratendinous inflammation. Treatment is based on whether to stimulate or prevent neovascularization. Thus, until now, there is no consensus as to the best treatment for this condition. This paper aims to review the common ways of treating this condition from the conservative to the surgical options. PMID:25729512

  6. Adolescent pregnancy options.

    PubMed

    Resnick, M D

    1992-09-01

    The range of pregnancy options available to adolescents each have significant ramifications for future educational and economic achievement. The changing societal context of adolescent pregnancy decision-making are described, and the characteristics of adolescents who choose to terminate their pregnancy, parent their child, or place for adoption are examined. The role of significant others in decision-making and the implications of mandatory parental involvement in pregnancy decision-making is discussed, as well as the roles of schools in promoting the well-being and potential of adolescents considering pregnancy decisions. PMID:1434557

  7. [Interventional neuroradiology: current options].

    PubMed

    Szikora, István; Marosfői, Miklós; Berentei, Zsolt; Gubucz, István

    2015-04-26

    Modern interventional neuroradiology has a leading role in the treatment of ischemic and hemorrhagic stroke, and it provides more and more important treatment options for degenerative diseases of the vertebral column and the management of correlated pain. During the last decades interventional neuroradiology has played a primary role in the treatment of intracranial berry aneurysms due to the continuous technical improvements. Ongoing studies proved superiority of mechanical stent-thrombectomy in acute proximal occlusion of cerebral arteries. Less invasive neurointerventional methods, such as vertebroplasty, are widely used in osteoporotic and neoplastic pathologic fractures of the vertebral bodies. These treatments should be performed in a specialized center by well trained physicians. PMID:26047151

  8. Options for Mars exploration

    NASA Technical Reports Server (NTRS)

    Pritchard, E. B.; Harrison, E. F.; Moore, J. W.

    1974-01-01

    The many possible post-Viking 1975 Mars mission options are explored. These include small atmospheric probe/landers (adaptations of the Venus Pioneer to Mars), repeat Vikings with and without science changes, long-life orbiters to provide coverage of both hemispheres for a full Martian year, small rovers deployed from the Viking lander with ranges of up to 1 km from it, large autonomous rovers, Mars sample-return missions and, finally, missions to the satellites of Mars, including sample return. The examination includes energy requirements and time frames.

  9. Martingale option pricing

    NASA Astrophysics Data System (ADS)

    McCauley, J. L.; Gunaratne, G. H.; Bassler, K. E.

    2007-07-01

    We show that our earlier generalization of the Black-Scholes partial differential equation (pde) for variable diffusion coefficients is equivalent to a Martingale in the risk neutral discounted stock price. Previously, the equivalence of Black-Scholes to a Martingale was proven for the case of the Gaussian returns model by Harrison and Kreps, but we prove it for a much larger class of returns models where the returns diffusion coefficient depends irreducibly on both returns x and time t. That option prices blow up if fat tails in logarithmic returns x are included in market return is also proven.

  10. The Mescalero option

    SciTech Connect

    Carter, L.J.

    1994-09-01

    The troubled state of the nations`s nuclear waste program is now more apparent than ever from the heated controversy that has emerged over a joint storage venture between some 30 utilities and the Mescalero Apache tribe of New Mexico. Tired of waiting for the government to make good on its promise to store nuclear waste, the utilities have struck out on their own. A monitored retrievable storage (MRS) facility for nuclear waste would give the utilities a place to store upto to 10,000 metric tons of spent fuels. Fees could run as high as $25 million per year. The Mescalero MRS facility would be developed and operated by a corporate entity owned in part by the utilities, with the Mescalero tribe holding the majority share. For this joint venture to succeed the utilities and Mescaleros must prevail over strong opposition by New Mexico officials and environmental and nuclear activists, all of whom want spent reactor fuel kept out. Spent fuel would be shipped to the reservation by rail. Sealed canisters containing the fuel would then be removed from the transport casks and inserted in fixed storage modeus providing massive shielding. Ownership of the fuel would remain with the utilities, and the license from the U.S. Nuclear Regulatory Commission, to be based on extensive environmental and safety studies, would initially be for 20 years. By law the Department of Energy (DOE) is supposed to begin accepting spent fuel from the utilities on January 321, 1998. But nothing has been accomplished to this end - despite nearly 12 years since the Nuclear Waste Policy Act. The most obvious and most likely, solution to the utilities problems is a congressional mandate for DOE to build an MRS at the Nevada Test Site either at or near Yucca Mountain.

  11. Damage development, phase changes, transport properties, and freeze-thaw performance of cementitious materials exposed to chloride based salts

    NASA Astrophysics Data System (ADS)

    Farnam, Yaghoob

    Recently, there has been a dramatic increase in premature deterioration in concrete pavements and flat works that are exposed to chloride based salts. Chloride based salts can cause damage and deterioration in concrete due to the combination of factors which include: increased saturation, ice formation, salt crystallization, osmotic pressure, corrosion in steel reinforcement, and/or deleterious chemical reactions. This thesis discusses how chloride based salts interact with cementitious materials to (1) develop damage in concrete, (2) create new chemical phases in concrete, (3) alter transport properties of concrete, and (4) change the concrete freeze-thaw performance. A longitudinal guarded comparative calorimeter (LGCC) was developed to simultaneously measure heat flow, damage development, and phase changes in mortar samples exposed to sodium chloride (NaCl), calcium chloride (CaCl 2), and magnesium chloride (MgCl2) under thermal cycling. Acoustic emission and electrical resistivity measurements were used in conjunction with the LGCC to assess damage development and electrical response of mortar samples during cooling and heating. A low-temperature differential scanning calorimetry (LT-DSC) was used to evaluate the chemical interaction that occurs between the constituents of cementitious materials (i.e., pore solution, calcium hydroxide, and hydrated cement paste) and salts. Salts were observed to alter the classical phase diagram for a salt-water system which has been conventionally used to interpret the freeze-thaw behavior in concrete. An additional chemical phase change was observed for a concrete-salt-water system resulting in severe damage in cementitious materials. In a cementitious system exposed to NaCl, the chemical phase change occurs at a temperature range between -6 °C and 8 °C due to the presence of calcium sulfoaluminate phases in concrete. As a result, concrete exposed to NaCl can experience additional freeze-thaw cycles due to the chemical

  12. Damage development, phase changes, transport properties, and freeze-thaw performance of cementitious materials exposed to chloride based salts

    NASA Astrophysics Data System (ADS)

    Farnam, Yaghoob

    Recently, there has been a dramatic increase in premature deterioration in concrete pavements and flat works that are exposed to chloride based salts. Chloride based salts can cause damage and deterioration in concrete due to the combination of factors which include: increased saturation, ice formation, salt crystallization, osmotic pressure, corrosion in steel reinforcement, and/or deleterious chemical reactions. This thesis discusses how chloride based salts interact with cementitious materials to (1) develop damage in concrete, (2) create new chemical phases in concrete, (3) alter transport properties of concrete, and (4) change the concrete freeze-thaw performance. A longitudinal guarded comparative calorimeter (LGCC) was developed to simultaneously measure heat flow, damage development, and phase changes in mortar samples exposed to sodium chloride (NaCl), calcium chloride (CaCl 2), and magnesium chloride (MgCl2) under thermal cycling. Acoustic emission and electrical resistivity measurements were used in conjunction with the LGCC to assess damage development and electrical response of mortar samples during cooling and heating. A low-temperature differential scanning calorimetry (LT-DSC) was used to evaluate the chemical interaction that occurs between the constituents of cementitious materials (i.e., pore solution, calcium hydroxide, and hydrated cement paste) and salts. Salts were observed to alter the classical phase diagram for a salt-water system which has been conventionally used to interpret the freeze-thaw behavior in concrete. An additional chemical phase change was observed for a concrete-salt-water system resulting in severe damage in cementitious materials. In a cementitious system exposed to NaCl, the chemical phase change occurs at a temperature range between -6 °C and 8 °C due to the presence of calcium sulfoaluminate phases in concrete. As a result, concrete exposed to NaCl can experience additional freeze-thaw cycles due to the chemical

  13. Avoidable waste management costs

    SciTech Connect

    Hsu, K.; Burns, M.; Priebe, S.; Robinson, P.

    1995-01-01

    This report describes the activity based costing method used to acquire variable (volume dependent or avoidable) waste management cost data for routine operations at Department of Energy (DOE) facilities. Waste volumes from environmental restoration, facility stabilization activities, and legacy waste were specifically excluded from this effort. A core team consisting of Idaho National Engineering Laboratory, Los Alamos National Laboratory, Rocky Flats Environmental Technology Site, and Oak Ridge Reservation developed and piloted the methodology, which can be used to determine avoidable waste management costs. The method developed to gather information was based on activity based costing, which is a common industrial engineering technique. Sites submitted separate flow diagrams that showed the progression of work from activity to activity for each waste type or treatability group. Each activity on a flow diagram was described in a narrative, which detailed the scope of the activity. Labor and material costs based on a unit quantity of waste being processed were then summed to generate a total cost for that flow diagram. Cross-complex values were calculated by determining a weighted average for each waste type or treatability group based on the volume generated. This study will provide DOE and contractors with a better understanding of waste management processes and their associated costs. Other potential benefits include providing cost data for sites to perform consistent cost/benefit analysis of waste minimization and pollution prevention (WMIN/PP) options identified during pollution prevention opportunity assessments and providing a means for prioritizing and allocating limited resources for WMIN/PP.

  14. Secondary propulsion system options for Space Station Freedom

    NASA Astrophysics Data System (ADS)

    Zimmermann, Frank S.; France, Cory P.

    1992-07-01

    This paper considers secondary propulsion system options for Space Station Freedom which make use of excess onboard water and resupplied water to provide up to 90 percent of the Space Station propulsion needs. The water resistojet and both low-thrust and high-thrust hydrogen-oxygen propulsion systems are compared in terms of complexity, development risk, performance, and propellant-resupply requirements. These options could provide a reduction in propellant resupply in excess of five shuttle flights over an eleven-year solar cycle. Upon implementation of a low-thrust option, the Space Station high-thrust hydrazine primary propulsion system would be used to perform attitude control and collision avoidance maneuvers only while the secondary propulsion system would compensate for atmospheric drag. The options offered for consideration would be installed after the establishment of a permanently manned capability when adequate quantities of waste water are available and reboost propellant requirements become most significant.

  15. Precipitation and Deposition of Aluminum-Containing Species in Tank Wastes

    SciTech Connect

    Mattigod, Shas V.; Hobbs, David T.; Wang, Li-Qiong; Dabbs, Daniel M.; Aksay, Ilhan A.

    2002-06-01

    Aluminum-containing phases represent the most prevalent solids that can appear or disappear during the processing of radioactive tank wastes. Processes such as sludge washing and leaching are designed to dissolve Al-containing phases and thereby minimize the volume of high-level waste glass required to encapsulate radioactive sludges. Unfortunately, waste-processing steps that include evaporation can involve solutions that are supersaturated with respect to cementitious aluminosilicates that result in unwanted precipitation and scale formation. Of all the constituents of tank waste, limited solubility cementitious aluminosilicates have the greatest potential for clogging pipes and transfer lines, fouling highly radioactive components such as ion exchangers, and completely shutting down processing operations. For instance, deposit buildup and clogged drain lines experienced during the tank waste volume-reduction process at the Savannah River Site (SRS) required an evaporator to be shut down in October 1999. The Waste Processing Technology Section of Westinghouse Savannah River Company at SRS now is collaborating with team members from Pacific Northwest National Laboratory (PNNL) to verify the thermodynamic stability of aluminosilicate compounds under waste tank conditions in an attempt to solve the deposition and clogging problems. The primary objectives of this study are (1) to understand the major factors controlling precipitation, heterogeneous nucleation, and growth phenomena of relatively insoluble aluminosilicates; (2) to determine the role of organics for inhibiting aluminosilicate formation, and (3) to develop a predictive tool to control precipitation, scale formation, and cementation under tank waste processing conditions. The results of this work will provide crucial information for (1) avoiding problematical sludge processing steps and (2) identifying and developing effective technologies to process retrieved sludges and supernatants before ultimate

  16. INEL Operable Unit 7-13 containment and stabilization configuration option

    SciTech Connect

    Raivo, B.D.; Richardson, J.G.; Nickelson, D.F.

    1993-05-01

    A containment and stabilization configuration option has been developed for the Idaho National Engineering Laboratory`s Subsurface Disposal Area Operable Unit 7-13, the transuranic (TRU)-contaminated waste pits and trenches. The configuration option is presented as an end-to-end system block diagram. Functional subelements are separately discussed, and technical background information, assumptions, input, high-level subelement requirements, and output are presented for each option.

  17. Grout treatment facility dangerous waste permit application

    SciTech Connect

    Not Available

    1988-11-23

    The long-term performance of the grout disposal system for Phosphate/Sulfate Waste (PSW) was analyzed. PSW is a low-level liquid generated by activities associated with N Reactor operations. The waste will be mixed with dry solids and permanently disposed of as a cementitious grout in sub-surface concrete vaults at Hanford's 200-East Area. Two categories of scenarios were analyzed that could cause humans to be exposed to radionuclides and chemicals from the grouted waste: contaminated groundwater and direct intrusion. In the groundwater scenario, contaminants are released from the buried grout monoliths, then eventually transported via the groundwater to the Columbia River. As modeled, the contaminants are assumed to leach out of the monoliths at a constant rate over a 10,000-year period. The other category of exposure involves intruders who inadvertently contact the waste directly, either by drilling, excavating, or gardening. Long-term impacts that could result from disposal of PSW grout were expressed in terms of incremental increases of (1) chemical concentrations in the groundwater and surface waters, and (2) radiation doses. None of the calculated impacts exceeded the corresponding regulatory limits set by Washington State, Department of Energy, or the Nuclear Regulatory Commission.

  18. Scientific basis for nuclear waste management XVI

    SciTech Connect

    Interrante, C.G.; Pabalan, R.T.

    1993-12-31

    One most significant aspect of this particular symposium is the focus on the scientific basis for management of nuclear waste. Engineering principles and practices are important, but this symposium focuses on the science. The extension and application of engineering ``know how`` to waste management problems sometimes requires a degree of understanding not normally needed to solve other engineering problems. In materials science, for example, scientific understandings important to long-term behavior may be obtained from (1) characterizations and analyses of the structure and properties of materials, (2) the recognition of advancements needed to ensure performance, and (3) improvements in methods of fabrication and processing. In addition to the materials science topics addressed here (on waste forms, engineered barrier systems, and the near-field environment), the symposium addressed various far-field topics. The proceedings are divided into the following sections: spent fuel; glass and crystalline waste forms; glass performance--mechanisms and models; cementitious materials; container alteration; microbiologically influenced corrosion; near-field interactions; natural analogues; long-term prediction for engineered barriers; performance assessment of engineered barrier systems; radionuclide chemistry and transport; and performance assessment of geological systems. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  19. Use of X-ray diffraction to quantify amorphous supplementary cementitious materials in anhydrous and hydrated blended cements

    SciTech Connect

    Snellings, R.; Salze, A.; Scrivener, K.L.

    2014-10-15

    The content of individual amorphous supplementary cementitious materials (SCMs) in anhydrous and hydrated blended cements was quantified by the PONKCS [1] X-ray diffraction (XRD) method. The analytical precision and accuracy of the method were assessed through comparison to a series of mixes of known phase composition and of increasing complexity. A 2σ precision smaller than 2–3 wt.% and an accuracy better than 2 wt.% were achieved for SCMs in mixes with quartz, anhydrous Portland cement, and hydrated Portland cement. The extent of reaction of SCMs in hydrating binders measured by XRD was 1) internally consistent as confirmed through the standard addition method and 2) showed a linear correlation to the cumulative heat release as measured independently by isothermal conduction calorimetry. The advantages, limitations and applicability of the method are discussed with reference to existing methods that measure the degree of reaction of SCMs in blended cements.

  20. Influence of silica fume on the immobilization properties of cementitious mortars exposed to freeze-thaw cycles

    SciTech Connect

    Quaresima, R.; Scoccia, G.; Volpe, R.; Medici, F.; Merli, C.

    1996-12-31

    This study deals with the durability of immobilization matrices, drawing comparisons among the release characteristics of cementitious mortars with or without silica fume, before and after freezing-thawing cycles. Three different dosages of silica fume have been experimented, using silica fume as a substitute of cement. The results obtained from the leaching tests have emphasized, in all the matrices which had undergone the freeze-thaw cycles, an increase of the percentage of tracer released with respect to the same matrices before the freezing-thawing cycles. As a consequence of the freezing-thawing cycles, the velocity of release has also increased in all the experimented matrices. However, the tests have reconfirmed the positive effect of the addition of silica fume.

  1. Mars Surface Habitability Options

    NASA Technical Reports Server (NTRS)

    Howe, A. Scott; Simon, Matthew; Smitherman, David; Howard, Robert; Toups, Larry; Hoffman, Stephen J.

    2015-01-01

    This paper reports on current habitability concepts for an Evolvable Mars Campaign (EMC) prepared by the NASA Human Spaceflight Architecture Team (HAT). For many years NASA has investigated alternative human Mars missions, examining different mission objectives, trajectories, vehicles, and technologies; the combinations of which have been referred to as reference missions or architectures. At the highest levels, decisions regarding the timing and objectives for a human mission to Mars continue to evolve while at the lowest levels, applicable technologies continue to advance. This results in an on-going need for assessments of alternative system designs such as the habitat, a significant element in any human Mars mission scenario, to provide meaningful design sensitivity characterizations to assist decision-makers regarding timing, objectives, and technologies. As a subset of the Evolvable Mars Campaign activities, the habitability team builds upon results from past studies and recommends options for Mars surface habitability compatible with updated technologies.

  2. Achalasia: current treatment options.

    PubMed

    Familiari, Pietro; Greco, Santi; Volkanovska, Ance; Gigante, Giovanni; Cali, Anna; Boškoski, Ivo; Costamagna, Guido

    2015-01-01

    Achalasia is a rare esophageal motility disorder, characterized by impaired swallow-induced, lower esophageal sphincter (LES) relaxation and defective esophageal peristalsis. Unfortunately, there are no etiological therapies for achalasia. Patients present with dysphagia, chest pain and regurgitation of undigested food, often leading to weight loss. The currently available treatments have the common aim of relieving symptoms by decreasing the pressure of the LES. This can be achieved with some medications, by inhibiting the cholinergic innervation (botulinum toxin), by stretching (endoscopic dilation) or cutting (surgery) the LES. Recently, other therapeutic options, including per-oral endoscopic myotomy have been developed and are gaining international consensus. The authors report on the benefits and weaknesses of the different therapies and provide an updated approach to the management of achalasia. PMID:26186641

  3. TOPEX satellite option study

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The basic design of the fleet satellite communication spacecraft (FLTSATCOM) can easily accommodate any of the three payload options for the ocean dynamic topography experiment (TOPEX). The principal mission requirements as well as the payload accommodations and communications systems needed for launching this payload are reviewed. The existing FLTSATCOM satellite design is identified and the approaches for the proposed propulsion system are described in addition to subsystems for mechanical; power; attitude and velocity control; and telemetry, tracking and control are described. The compatability of FLTSATCOM with the launch vehicle is examined and its capabilities vs TOPEX requirements are summarized. Undetermined changes needed to meet data storage, thermal control, and area to mass ratio requirements are discussed. Cost estimates are included for budgetary and planning purposes. The availability of the described design is assessed based on the continuing production of FLTSATCOM spacecraft during the schedule span planned for TOPEX.

  4. Early amplification options.

    PubMed

    Gabbard, Sandra Abbott; Schryer, Jennifer

    2003-01-01

    Children with permanent hearing loss have been remediated with hearing amplification devices for decades. The influx of young infants identified with hearing loss through successful newborn hearing screening programs has established a need for amplification resources for infants within the first six months of life. For the approximately two of every 1000 infants born who are identified with bilateral hearing loss [Mehl and Thomson, 1998, Pediatrics 101, p. e4], the use of amplification is commonly the first step in treating the sequella of their loss. The use of hearing aids, combined with early intervention, has been shown to significantly improve the speech and language skills of young children with hearing loss [Yoshinaga-Itano, 2000, Seminars in Hearing 21, p. 309]. Speech and language delays have contributed to compromised academic performance of school aged children with hearing loss [Johnson et al., 1997, Educational Audiology Handbook, Singular Publishing, San Diego]. Most hard-of-hearing and deaf children use hearing aids and other assistive listening devices every day throughout their lifetime and the life expectancy of a hearing aid is only five to eight years. The current challenge for pediatric audiologists is selecting and evaluating the available amplification to provide the best options for children and their families. Amplification technology has seen an explosion in growth the past few years and the options continue to expand rapidly. This article examines currently available amplification technology and reviews the selection criteria that may be used for infants and young children. Issues such as style, type, amplification features, signal processing strategies, and verification and validation tools are also discussed. PMID:14648816

  5. Peak load management: Potential options

    SciTech Connect

    Englin, J.E.; De Steese, J.G.; Schultz, R.W.; Kellogg, M.A.

    1989-10-01

    This report reviews options that may be alternatives to transmission construction (ATT) applicable both generally and at specific locations in the service area of the Bonneville Power Administration (BPA). Some of these options have potential as specific alternatives to the Shelton-Fairmount 230-kV Reinforcement Project, which is the focus of this study. A listing of 31 peak load management (PLM) options is included. Estimated costs and normalized hourly load shapes, corresponding to the respective base load and controlled load cases, are considered for 15 of the above options. A summary page is presented for each of these options, grouped with respect to its applicability in the residential, commercial, industrial, and agricultural sectors. The report contains comments on PLM measures for which load shape management characteristics are not yet available. These comments address the potential relevance of the options and the possible difficulty that may be encountered in characterizing their value should be of interest in this investigation. The report also identifies options that could improve the efficiency of the three customer utility distribution systems supplied by the Shelton-Fairmount Reinforcement Project. Potential cogeneration options in the Olympic Peninsula are also discussed. These discussions focus on the options that appear to be most promising on the Olympic Peninsula. Finally, a short list of options is recommended for investigation in the next phase of this study. 9 refs., 24 tabs.

  6. National Institutes of Health: Mixed waste minimization and treatment

    SciTech Connect

    1995-08-01

    The Appalachian States Low-Level Radioactive Waste Commission requested the US Department of Energy`s National Low-Level Waste Management Program (NLLWMP) to assist the biomedical community in becoming more knowledgeable about its mixed waste streams, to help minimize the mixed waste stream generated by the biomedical community, and to identify applicable treatment technologies for these mixed waste streams. As the first step in the waste minimization process, liquid low-level radioactive mixed waste (LLMW) streams generated at the National Institutes of Health (NIH) were characterized and combined into similar process categories. This report identifies possible waste minimization and treatment approaches for the LLMW generated by the biomedical community identified in DOE/LLW-208. In development of the report, on site meetings were conducted with NIH personnel responsible for generating each category of waste identified as lacking disposal options. Based on the meetings and general waste minimization guidelines, potential waste minimization options were identified.

  7. Experimental and numerical investigation of the dynamic response of highly compliant, polymer-enhanced, graphite-reinforced cementitious composites

    NASA Astrophysics Data System (ADS)

    Ooi, Teng Keong

    This dissertation demonstrates how composite materials, fabricated by placing a low modulus, lightweight polymer-enhanced, cementitious matrix over multiple layers of stiff reinforcement, can be used to create a composite material with relatively high tension and compression properties. This extraordinary combination allows a structure to be highly stressed and deformed to store large amounts of elastic strain energy, thus providing more design flexibility than traditional materials. When the structural response is modified as the service loads are decreased, the energy is released in a controlled fashion to do useful work. Prior research shows that the standard transform section method fails to provide accurate results when the elastic modulus ratio exceeds 20. A modified transformed section is formulated by using the rule of mixture to determine the effective material properties for the composite. Finite element analysis is used to verify the experimental results and a good agreement is obtained. This dissertation investigates the experimental and numerical methods to determine the dynamic response of this new class of highly compliant, Polymer-Enhanced, Graphite Reinforced Cementitious Composite (PEGRCC) materials. Highly compliant, PEGRCC structures are designed based on the strength, stiffness, and the position of the component materials in the composite section. Their ability to store and release energy depends upon a complex interaction between the shape, modal response, and the forcing function initiated to the structure. This dissertation shows that the PEGRCC materials behave like a composite material and the classical mechanics of composite material theory is applicable to PEGRCC laminates. The good agreement between the experimental natural frequencies and mode shapes and the finite element predictions indicate that the standard mechanical impact testing can be adopted to test PEGRCC materials. The accuracy of the finite element dynamic analysis shows

  8. Hanford Tank Waste - Near Source Treatment of Low Activity Waste

    SciTech Connect

    Ramsey, William Gene

    2013-08-15

    describes the potential near source treatment and waste disposition options as well as the impact these options could have on reducing infrastructure requirements, project cost and mission schedule.

  9. GEOTECHNICAL/GEOCHEMICAL CHARACTERIZATION OF ADVANCED COAL PROCESS WASTE STREAMS

    SciTech Connect

    Edwin S. Olson; Charles J. Moretti

    1999-11-01

    Thirteen solid wastes, six coals and one unreacted sorbent produced from seven advanced coal utilization processes were characterized for task three of this project. The advanced processes from which samples were obtained included a gas-reburning sorbent injection process, a pressurized fluidized-bed coal combustion process, a coal-reburning process, a SO{sub x}, NO{sub x}, RO{sub x}, BOX process, an advanced flue desulfurization process, and an advanced coal cleaning process. The waste samples ranged from coarse materials, such as bottom ashes and spent bed materials, to fine materials such as fly ashes and cyclone ashes. Based on the results of the waste characterizations, an analysis of appropriate waste management practices for the advanced process wastes was done. The analysis indicated that using conventional waste management technology should be possible for disposal of all the advanced process wastes studied for task three. However, some wastes did possess properties that could present special problems for conventional waste management systems. Several task three wastes were self-hardening materials and one was self-heating. Self-hardening is caused by cementitious and pozzolanic reactions that occur when water is added to the waste. All of the self-hardening wastes setup slowly (in a matter of hours or days rather than minutes). Thus these wastes can still be handled with conventional management systems if care is taken not to allow them to setup in storage bins or transport vehicles. Waste self-heating is caused by the exothermic hydration of lime when the waste is mixed with conditioning water. If enough lime is present, the temperature of the waste will rise until steam is produced. It is recommended that self-heating wastes be conditioned in a controlled manner so that the heat will be safely dissipated before the material is transported to an ultimate disposal site. Waste utilization is important because an advanced process waste will not require

  10. A Program on Hazardous Waste Management.

    ERIC Educational Resources Information Center

    Kummler, Ralph H.; And Others

    1989-01-01

    Provides an overview of the "Hazardous Waste Management Graduate Certificate" program at Wayne State University. Describes four required courses and nine optional courses. Discusses the development of a Master program and the curriculum of the Master program. (YP)

  11. Low-level waste forum meeting reports

    SciTech Connect

    1992-12-31

    This report provides highlights from the 1992 fall meeting of the Low LEvel Radioactive Waste Forum. Topics included: disposal options after 1992; interregional agreements; management alternatives; policy; and storage.

  12. Solid waste retrieval. Phase 1, Operational basis

    SciTech Connect

    Johnson, D.M.

    1994-09-30

    This Document describes the operational requirements, procedures, and options for execution of the retrieval of the waste containers placed in buried storage in Burial Ground 218W-4C, Trench 04 as TRU waste or suspect TRU waste under the activity levels defining this waste in effect at the time of placement. Trench 04 in Burial Ground 218W-4C is totally dedicated to storage of retrievable TRU waste containers or retrievable suspect TRU waste containers and has not been used for any other purpose.

  13. Treatment of organic waste

    DOEpatents

    Grantham, LeRoy F.

    1979-01-01

    An organic waste containing at least one element selected from the group consisting of strontium, cesium, iodine and ruthenium is treated to achieve a substantial reduction in the volume of the waste and provide for fixation of the selected element in an inert salt. The method of treatment comprises introducing the organic waste and a source of oxygen into a molten salt bath maintained at an elevated temperature to produce solid and gaseous reaction products. The gaseous reaction products comprise carbon dioxide and water vapor, and the solid reaction products comprise the inorganic ash constituents of the organic waste and the selected element which is retained in the molten salt. The molten salt bath comprises one or more alkali metal carbonates, and may optionally include from 1 to about 25 wt.% of an alkali metal sulfate.

  14. Mixed Waste Encapsulation in Polyester Resins. Treatment for Mixed Wastes Containing Salts. Mixed Waste Focus Area. OST Reference #1685

    SciTech Connect

    None, None

    1999-09-01

    formulation recipes. As an alternative to thermal treatments, low-temperature stabilization of these materials in basic cementitious grouts has also been widely employed. However, salts interfere with the basic hydration reactions of Portland cement, leading to an inadequate set or deterioration of the waste form over time. Sufficient and compliant stabilization in cement can be achieved by lowering waste loadings, but this involves a large and costly increase in the volume of material requiring handling, transporting, and disposal.

  15. 20 CFR 416.2035 - Optional supplementation: Additional State options.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Optional supplementation: Additional State options. 416.2035 Section 416.2035 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED State Supplementation Provisions; Agreement;...

  16. 20 CFR 416.2035 - Optional supplementation: Additional State options.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Optional supplementation: Additional State options. 416.2035 Section 416.2035 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED State Supplementation Provisions; Agreement;...

  17. Selected Energy Conservation Options for Homeowners: Options, Expenses and Payoffs.

    ERIC Educational Resources Information Center

    Lengyel, Dorothy L.; And Others

    This publication is a check list for homeowners and renters to help them reduce energy costs. The list consists of 126 energy conservation options. These options range from "change clothes instead of adjusting thermostat" and "air conditioners turned off when not home" to "use sink stopper" and "weatherstripping and caulking applied." For each…

  18. Maintenance and supply options

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The object of the Maintenance and Supply Option was to develop a high level operational philosophy related to maintenance and supply operations and incorporate these concepts into the Lunar Base Study. Specific products to be generated during this task were three trade studies and a conceptual design of the Logistic Supply Module. The crew size study was performed to evaluate crew sizes from the baseline size of four to a crew size of eight and determine the preferred crew size. The second trade study was to determine the impact of extending surface stay times and recommend a preferred duration of stay time as a function of crew, consumables, and equipment support capabilities. The third trade study was an evaluation of packaging and storage methods to determine the preferred logistics approach to support the lunar base. A modified scenario was developed and served as the basis of the individual trade studies. Assumptions and guidelines were also developed from experience with Apollo programs, Space Shuttle operations, and Space Station studies. With this information, the trade studies were performed and a conceptual design for the Logistic Supply Module was developed.

  19. Treatment Options for Narcolepsy.

    PubMed

    Barateau, Lucie; Lopez, Régis; Dauvilliers, Yves

    2016-05-01

    Narcolepsy type 1 and narcolepsy type 2 are central disorders of hypersomnolence. Narcolepsy type 1 is characterized by excessive daytime sleepiness and cataplexy and is associated with hypocretin-1 deficiency. On the other hand, in narcolepsy type 2, cerebrospinal fluid hypocretin-1 levels are normal and cataplexy absent. Despite major advances in our understanding of narcolepsy mechanisms, its current management is only symptomatic. Treatment options may vary from a single drug that targets several symptoms, or multiple medications that each treats a specific symptom. In recent years, narcolepsy treatment has changed with the widespread use of modafinil/armodafinil for daytime sleepiness, antidepressants (selective serotonin and dual serotonin and noradrenalin reuptake inhibitors) for cataplexy, and sodium oxybate for both symptoms. Other psychostimulants can also be used, such as methylphenidate, pitolisant and rarely amphetamines, as third-line therapy. Importantly, clinically relevant subjective and objective measures of daytime sleepiness are required to monitor the treatment efficacy and to provide guidance on whether the treatment goals are met. Associated symptoms and comorbid conditions, such as hypnagogic/hypnopompic hallucinations, sleep paralysis, disturbed nighttime sleep, unpleasant dreams, REM- and non REM-related parasomnias, depressive symptoms, overweight/obesity, and obstructive sleep apnea, should also be taken into account and managed, if required. In the near future, the efficacy of new wake-promoting drugs, anticataplectic agents, hypocretin replacement therapy and immunotherapy at the early stages of the disease should also be evaluated. PMID:27155860

  20. Pediatric Glaucoma: Pharmacotherapeutic Options.

    PubMed

    Samant, Monica; Medsinge, Anagha; Nischal, Ken K

    2016-06-01

    Childhood glaucoma is a major therapeutic challenge for pediatric ophthalmologists and glaucoma specialists worldwide. Management depends on the etiology and age at presentation. A variety of drugs are available for the control of intraocular pressure in children; however, none of these drugs have been licensed by the regulatory agencies for use in children. Furthermore, evidence gained from randomized controlled trials in the pediatric population is sparse, and little is known regarding the use of newer anti-glaucoma preparations. This evidence-based review aims to discuss the available pharmacotherapeutic options for glaucoma in children. Topical adrenoceptor blockers, topical and systemic carbonic anhydrase inhibitors, prostaglandin (PG) analogs, adrenoceptor agonists, parasympathomimetics, and combined preparations are available for use in children, but usually as an off-label indication. Therefore, it is important to recognize that serious side effects have been reported, even with topical drops, and measures to reduce systemic absorption should be taken. Most drugs have been shown to have comparable ocular hypotensive effects, with the lowest occurrence of systemic side effects with PG analogs. Whereas a newly introduced prostaglandin analog, tafluprost, and some other preservative-free preparations have shown promising results in adult glaucoma patients, no pediatric reports are available as yet. Future studies may describe their role in treating pediatric glaucoma. This review also shares some suggested treatment pathways for primary congenital glaucoma (PCG), juvenile open angle glaucoma (JOAG), developmental glaucoma, aphakic/pseudophakic glaucoma, and uveitic glaucoma. PMID:27093864

  1. Effluent treatment options for nuclear thermal propulsion system ground tests

    SciTech Connect

    Shipers, L.R.; Brockmann, J.E.

    1992-10-16

    A variety of approaches for handling effluent from nuclear thermal propulsion system ground tests in an environmentally acceptable manner are discussed. The functional requirements of effluent treatment are defined and concept options are presented within the framework of these requirements. System concepts differ primarily in the choice of fission-product retention and waste handling concepts. The concept options considered range from closed cycle (venting the exhaust to a closed volume or recirculating the hydrogen in a closed loop) to open cycle (real time processing and venting of the effluent). This paper reviews the strengths and weaknesses of different methods to handle effluent from nuclear thermal propulsion system ground tests.

  2. Mixed Waste Working Group report

    SciTech Connect

    Not Available

    1993-11-09

    The treatment of mixed waste remains one of this country`s most vexing environmental problems. Mixed waste is the combination of radioactive waste and hazardous waste, as defined by the Resource Conservation and Recovery Act (RCRA). The Department of Energy (DOE), as the country`s largest mixed waste generator, responsible for 95 percent of the Nation`s mixed waste volume, is now required to address a strict set of milestones under the Federal Facility Compliance Act of 1992. DOE`s earlier failure to adequately address the storage and treatment issues associated with mixed waste has led to a significant backlog of temporarily stored waste, significant quantities of buried waste, limited permanent disposal options, and inadequate treatment solutions. Between May and November of 1993, the Mixed Waste Working Group brought together stakeholders from around the Nation. Scientists, citizens, entrepreneurs, and bureaucrats convened in a series of forums to chart a course for accelerated testing of innovative mixed waste technologies. For the first time, a wide range of stakeholders were asked to examine new technologies that, if given the chance to be tested and evaluated, offer the prospect for better, safer, cheaper, and faster solutions to the mixed waste problem. In a matter of months, the Working Group has managed to bridge a gap between science and perception, engineer and citizen, and has developed a shared program for testing new technologies.

  3. Baseline Glass Development for Combined Fission Products Waste Streams

    SciTech Connect

    Crum, Jarrod V.; Billings, Amanda Y.; Lang, Jesse B.; Marra, James C.; Rodriguez, Carmen P.; Ryan, Joseph V.; Vienna, John D.

    2009-06-29

    Borosilicate glass was selected as the baseline technology for immobilization of the Cs/Sr/Ba/Rb (Cs), lanthanide (Ln) and transition metal fission product (TM) waste steams as part of a cost benefit analysis study.[1] Vitrification of the combined waste streams have several advantages, minimization of the number of waste forms, a proven technology, and similarity to waste forms currently accepted for repository disposal. A joint study was undertaken by Pacific Northwest National Laboratory (PNNL) and Savannah River National Laboratory (SRNL) to develop acceptable glasses for the combined Cs + Ln + TM waste streams (Option 1) and Cs + Ln combined waste streams (Option 2) generated by the AFCI UREX+ set of processes. This study is aimed to develop baseline glasses for both combined waste stream options and identify key waste components and their impact on waste loading. The elemental compositions of the four-corners study were used along with the available separations data to determine the effect of burnup, decay, and separations variability on estimated waste stream compositions.[2-5] Two different components/scenarios were identified that could limit waste loading of the combined Cs + LN + TM waste streams, where as the combined Cs + LN waste stream has no single component that is perceived to limit waste loading. Combined Cs + LN waste stream in a glass waste form will most likely be limited by heat due to the high activity of Cs and Sr isotopes.

  4. Bench-scale feasibility testing of pulsed-air technology for in-tank mixing of dry cementitious solids with tank liquids and settled solids

    SciTech Connect

    Whyatt, G.A.; Hymas, C.R.

    1997-09-01

    This report documents the results of testing performed to determine the feasibility of using a pulsed-air mixing technology (equipment developed by Pulsair Systems, Inc., Bellevue, WA) to mix cementitious dry solids with supernatant and settled solids within a horizontal tank. The mixing technology is being considered to provide in situ stabilization of the {open_quotes}V{close_quotes} tanks at the Idaho National Engineering and Environmental Laboratory (INEEL). The testing was performed in a vessel roughly 1/6 the scale of the INEEL tanks. The tests used a fine soil to simulate settled solids and water to simulate tank supernatants. The cementitious dry materials consisted of Portland cement and Aquaset-2H (a product of Fluid Tech Inc. consisting of clay and Portland cement). Two scoping tests were conducted to allow suitable mixing parameters to be selected. The scoping tests used only visual observations during grout disassembly to assess mixing performance. After the scoping tests indicated the approach may be feasible, an additional two mixing tests were conducted. In addition to visual observations during disassembly of the solidified grout, these tests included addition of chemical tracers and chemical analysis of samples to determine the degree of mixing uniformity achieved. The final two mixing tests demonstrated that the pulsed-air mixing technique is capable of producing slurries containing substantially more cementitious dry solids than indicated by the formulations suggested by INEEL staff. Including additional cement in the formulation may have benefits in terms of increasing mobilization of solids, reducing water separation during curing, and increasing the strength of the solidified product. During addition to the tank, the cementitious solids had a tendency to form clumps which broke down with continued mixing.

  5. Micro-structural characterization of the hydration products of bauxite-calcination-method red mud-coal gangue based cementitious materials.

    PubMed

    Liu, Xiaoming; Zhang, Na; Yao, Yuan; Sun, Henghu; Feng, Huan

    2013-11-15

    In this research, the micro-structural characterization of the hydration products of red mud-coal gangue based cementitious materials has been investigated through SEM-EDS, (27)Al MAS NMR and (29)Si MAS NMR techniques, in which the used red mud was derived from the bauxite calcination method. The results show that the red mud-coal gangue based cementitious materials mainly form fibrous C-A-S-H gel, needle-shaped/rod-like AFt in the early hydration period. With increasing of the hydration period, densification of the pastes were promoted resulting in the development of strength. EDS analysis shows that with the Ca/Si of red mud-coal gangue based cementitious materials increases, the average Ca/Si and Ca/(Si+Al) atomic ratio of C-A-S-H gel increases, while the average Al/Si atomic ratio of C-A-S-H gel decreases. MAS NMR analysis reveals that Al in the hydration products of red mud-coal gangue based cementitious materials exists in the forms of Al(IV) and Al(VI), but mainly in the form of Al(VI). Increasing the Ca/Si ratio of raw material promotes the conversion of [AlO4] to [AlO6] and inhibits the combination between [AlO4] and [SiO4] to form C-A-S-H gel. Meanwhile, the polymerization degree of [SiO4] in the hydration products declines. PMID:24076570

  6. Immobilization and Waste Form Product Acceptance for Low Level and TRU Waste Forms

    SciTech Connect

    Holtzscheiter, E.W.; Harbour, J.R.

    1998-05-01

    The Tanks Focus Area is supporting technology development in immobilization of both High Level (HLW) and Low Level (LLW) radioactive wastes. The HLW process development at Hanford and Idaho is patterned closely after that of the Savannah River (Defense Waste Processing Facility) and West Valley Sites (West Valley Demonstration Project). However, the development and options open to addressing Low Level Waste are diverse and often site specific. To start, it is important to understand the breadth of Low Level Wastes categories.

  7. Life cycle cost estimating of waste management facilities

    SciTech Connect

    Shropshire, D.; Feizollahi, F.; Teheranian, B.; Waldman, M.

    1994-12-31

    Waste Management Facilities cost Information (WMFCI) provides a modular cost method for estimating planning-level life-cycle costs of waste management alternatives. This methodology includes over 120 cost modules that cover a variety of treatment, storage, disposal, and support facility options. The WMFCI method can be used to estimate virtually every technology option and related facilities needed by the Department of Energy for cradle-to-grave management of hazardous, radioactive, mixed waste, and spent nuclear fuel. Various waste streams covered by the WMFCI are low-level waste (LLW), mixed low-level waste (MLLW), alpha contaminated LLW, alpha contaminated MLLW, transuranic waste, spent nuclear fuel, Greater-Than-Class C and DOE equivalent special case wastes, and hazardous wastes. The methodology also contains cost versus capacity relationships for each cost module to aid in estimating various waste management configurations.

  8. Waste management facility accident analysis (WASTE ACC) system: software for analysis of waste management alternatives

    SciTech Connect

    Kohout, E.F.; Folga, S.; Mueller, C.; Nabelssi, B.

    1996-03-01

    This paper describes the Waste Management Facility Accident Analysis (WASTE{underscore}ACC) software, which was developed at Argonne National Laboratory (ANL) to support the US Department of Energy`s (DOE`s) Waste Management (WM) Programmatic Environmental Impact Statement (PEIS). WASTE{underscore}ACC is a decision support and database system that is compatible with Microsoft{reg_sign} Windows{trademark}. It assesses potential atmospheric releases from accidents at waste management facilities. The software provides the user with an easy-to-use tool to determine the risk-dominant accident sequences for the many possible combinations of process technologies, waste and facility types, and alternative cases described in the WM PEIS. In addition, its structure will allow additional alternative cases and assumptions to be tested as part of the future DOE programmatic decision-making process. The WASTE{underscore}ACC system demonstrates one approach to performing a generic, systemwide evaluation of accident risks at waste management facilities. The advantages of WASTE{underscore}ACC are threefold. First, the software gets waste volume and radiological profile data that were used to perform other WM PEIS-related analyses directly from the WASTE{underscore}MGMT system. Second, the system allows for a consistent analysis across all sites and waste streams, which enables decision makers to understand more fully the trade-offs among various policy options and scenarios. Third, the system is easy to operate; even complex scenario runs are completed within minutes.

  9. Optional Extended Year Program. FEEDBACK.

    ERIC Educational Resources Information Center

    Washington, Wanda

    The Optional Extended Year (OEY) program was initiated in Texas in 1995 and was first implemented in the Austin Independent School District (AISD) in 1996. The OEY is designed to add an extended school year and reduce student retention through four school-day options: (1) extended day; (2) extended week; (3) intersessions for year-round schools;…

  10. Bounds for Asian basket options

    NASA Astrophysics Data System (ADS)

    Deelstra, Griselda; Diallo, Ibrahima; Vanmaele, Michèle

    2008-09-01

    In this paper we propose pricing bounds for European-style discrete arithmetic Asian basket options in a Black and Scholes framework. We start from methods used for basket options and Asian options. First, we use the general approach for deriving upper and lower bounds for stop-loss premia of sums of non-independent random variables as in Kaas et al. [Upper and lower bounds for sums of random variables, Insurance Math. Econom. 27 (2000) 151-168] or Dhaene et al. [The concept of comonotonicity in actuarial science and finance: theory, Insurance Math. Econom. 31(1) (2002) 3-33]. We generalize the methods in Deelstra et al. [Pricing of arithmetic basket options by conditioning, Insurance Math. Econom. 34 (2004) 55-57] and Vanmaele et al. [Bounds for the price of discrete sampled arithmetic Asian options, J. Comput. Appl. Math. 185(1) (2006) 51-90]. Afterwards we show how to derive an analytical closed-form expression for a lower bound in the non-comonotonic case. Finally, we derive upper bounds for Asian basket options by applying techniques as in Thompson [Fast narrow bounds on the value of Asian options, Working Paper, University of Cambridge, 1999] and Lord [Partially exact and bounded approximations for arithmetic Asian options, J. Comput. Finance 10 (2) (2006) 1-52]. Numerical results are included and on the basis of our numerical tests, we explain which method we recommend depending on moneyness and time-to-maturity.

  11. A Smorgasbord of Assessment Options

    ERIC Educational Resources Information Center

    Bacon, Kathy A.

    2010-01-01

    The wealth of assessment options that exists offers teachers and students a "menu" of selections. Just as matching appetite needs with appropriate food selection is fundamental to a successful dining experience, matching assessment options to targeted achievement needs is crucial to an effective assessment experience. The author uses a geometry…

  12. Waste Management Facilities cost information for low-level waste

    SciTech Connect

    Shropshire, D.; Sherick, M.; Biadgi, C.

    1995-06-01

    This report contains preconceptual designs and planning level life-cycle cost estimates for managing low-level waste. The report`s information on treatment, storage, and disposal modules can be integrated to develop total life-cycle costs for various waste management options. A procedure to guide the US Department of Energy and its contractor personnel in the use of cost estimation data is also summarized in this report.

  13. Waste management facilities cost information for hazardous waste. Revision 1

    SciTech Connect

    Shropshire, D.; Sherick, M.; Biagi, C.

    1995-06-01

    This report contains preconceptual designs and planning level life-cycle cost estimates for managing hazardous waste. The report`s information on treatment, storage, and disposal modules can be integrated to develop total life-cycle costs for various waste management options. A procedure to guide the US Department of Energy and its contractor personnel in the use of cost estimation data is also summarized in this report.

  14. Waste management facilities cost information for transuranic waste

    SciTech Connect

    Shropshire, D.; Sherick, M.; Biagi, C.

    1995-06-01

    This report contains preconceptual designs and planning level life-cycle cost estimates for managing transuranic waste. The report`s information on treatment and storage modules can be integrated to develop total life-cycle costs for various waste management options. A procedure to guide the U.S. Department of Energy and its contractor personnel in the use of cost estimation data is also summarized in this report.

  15. Waste Handeling Building Conceptual Study

    SciTech Connect

    G.W. Rowe

    2000-11-06

    The objective of the ''Waste Handling Building Conceptual Study'' is to develop proposed design requirements for the repository Waste Handling System in sufficient detail to allow the surface facility design to proceed to the License Application effort if the proposed requirements are approved by DOE. Proposed requirements were developed to further refine waste handling facility performance characteristics and design constraints with an emphasis on supporting modular construction, minimizing fuel inventory, and optimizing facility maintainability and dry handling operations. To meet this objective, this study attempts to provide an alternative design to the Site Recommendation design that is flexible, simple, reliable, and can be constructed in phases. The design concept will be input to the ''Modular Design/Construction and Operation Options Report'', which will address the overall program objectives and direction, including options and issues associated with transportation, the subsurface facility, and Total System Life Cycle Cost. This study (herein) is limited to the Waste Handling System and associated fuel staging system.

  16. Characterization of cementitiously stabilized subgrades for mechanistic-empirical pavement design

    NASA Astrophysics Data System (ADS)

    Solanki, Pranshoo

    Pavements are vulnerable to subgrade layer performance because it acts as a foundation. Due to increase in the truck traffic, pavement engineers are challenged to build more strong and long-lasting pavements. To increase the load-bearing capacity of pavements, subgrade layer is often stabilized with cementitious additives. Thus, an overall characterization of stabilized subgrade layer is important for enhanced short- and long-term pavement performance. In this study, the effect of type and amount of additive on the short-term performance in terms of material properties recommended by the new Mechanistic-Empirical Pavement Design Guide (MEPDG) is examined. A total of four soils commonly encountered as subgrades in Oklahoma are utilized. Results show that the changes in the Mr, ME and UCS values stabilized specimens depend on the soil type and properties of additives. The long-term performance (or durability) of stabilized soil specimens is investigated by conducting freeze-thaw (F-T) cycling, vacuum saturation and tube suction tests on 7-day cured P-, K- and C-soil specimens stabilized with 6% lime, 10% CFA and 10% CKD. This study is motivated by the fact that during the service life of pavement stabilized layers are subjected to F-T cycles and moisture variations. It is found that that UCS value of all the stabilized specimens decreased with increase in the number of F-T cycles. A strong correlation was observed between UCS values retained after vacuum saturation and F-T cycles indicating that vacuum saturation could be used as a time-efficient and inexpensive method for evaluating durability of stabilized soils. In this study, short- and long-term observations from stabilization of sulfate bearing soil with locally available low (CFA), moderate (CKD) and high (lime) calcium-based stabilizers are determined to evaluate and compare the effect of additive type on the phenomenon of sulfate-induced heave. The impact of different factors on the development of the

  17. Modeling Carbonation of High-Level Waste Tank Integrity and Closure

    NASA Astrophysics Data System (ADS)

    Brown, K. G.; Arnold, J.; Sarkar, S.; Flach, G.; van der Sloot, H.; Meeussen, J. C. L.; Kosson, D. S.

    2013-07-01

    The Cementitious Barriers Partnership (CBP) is focused on reducinguncertainties in current methodologies for assessing cementitious barrier performanceand increasing the consistency and transparency in the assessment process. Oneimportant set of US Department of Energy challenges is assessing the integrity andclosure of the high-level waste (HLW) tanks that currently store millions of gallons ofhighly radioactive wastes. Many of these tanks are decades past their design lives, haveleaked or been overfilled, and must be emptied and closed to satisfy regulatoryagreements. Carbonation-induced corrosion has been identified as a primary degradationand possible failure mechanism for the HLW tanks prior to closure. After closure theimpact of carbonation (and concurrent oxidation) may be to increase the release andshort-range transport of contaminants of concern. HLW tanks may be significantlyempty for many years (and possibly decades) prior to closure; the performance of theclosed tank over centuries, if not millennia, must be assessed to evaluate the potentialrelease of residual radionuclides to the environment. CBP is developing models to evaluate a representative HLW tank closure scenarioincluding the potential impacts of carbonation on waste tanks prior to and post closure.CBP modeling tools, including LeachXS™/ORCHESTRA, are being used to simulatewaste tank carbonation, major constituent leaching, and contaminant releases to evaluatethe source term and near-field conditions. Simulations presented here include sensitivityanalysis for uncracked concrete to varying input parameters including composition,effective diffusivities, and thermodynamic parameters.

  18. Innovative methodology for comprehensive utilization of iron ore tailings: part 2: The residues after iron recovery from iron ore tailings to prepare cementitious material.

    PubMed

    Li, Chao; Sun, Henghu; Yi, Zhonglai; Li, Longtu

    2010-02-15

    In order to comprehensive utilization of iron ore tailings, this experimental research was to investigate the possibility of using the residues after iron recovery from iron ore tailings as raw materials for the preparation of cementitious material, abbreviated as TSC, including analyses of its mechanical properties, physical properties and hydration products. The TSC1 was prepared by blending 30% the residues, 34% blast-furnace slag, 30% clinker and 6% gypsum. Meanwhile, the raw iron ore tailings (before iron recovery) with the same proportion of TSC1 were selected to compare the cementitious activity of raw tailings and the residues after magnetizing roasting, denoted by TSC0. The hydration products of them were mostly ettringite, calcium hydroxide and C-S-H gel, characterized by XRD, IR and SEM. It was found that ettringite and C-S-H gel were principally responsible for the strength development of TSC mortars with curing time. The results showed that the kaolinite of the tailings was decomposed completely after magnetizing roasting, which promoted the cementitious property of TSC1. Moreover, the mechanical properties of TSC1 are well comparable with those of 42.5 ordinary Portland cement according to Chinese GB175-2007 standard. PMID:19782471

  19. Waste minimization opportunity assessment: A photofinishing facility. Final report

    SciTech Connect

    Not Available

    1991-08-01

    A waste minimization opportunity assessment was performed which identified areas for waste reduction at a photofinishing facility. The study followed procedures in the EPA Waste Minimization Opportunity Assessment Manual. The report identifies potential options to achieve further waste minimization progress. A number of waste producing processes were initially screened, and detailed technical evaluations were performed on wastes associated with process solutions and wash waters. Options identified were as follows: (1) wash water control; (2) silver recovery--metal replacement cartridges; (3) silver recovery--electrowinning (4) electrowinning with MRC tailing; (5) recovery of silver--ion exchange; (6) recovery of fixer; (7) recovery of bleach fix; and (8) recovery of developer. Based on the results of the assessment phase, Options 1-4 and 7 were selected for further evaluation in the feasibility phase. The results of the study indicate the fastest payback would be realized from Options 1 and 7 assuming Accuphoto's willingness to recycle bleach and no production increases.

  20. Depleted uranium disposal options.

    SciTech Connect

    Biwer, B. M.; Ranek, N. L.; Goldberg, M.; Avci, H. I.

    2000-04-01

    Depleted uranium hexafluoride (UF{sub 6}) has been produced in the United States since the 1940s as part of both the military program and the civilian nuclear energy program. The U.S. Department of Energy (DOE) is the agency responsible for managing most of the depleted UF{sub 6} that has been produced in the United States. The total quantity of depleted UF{sub 6} that DOE has to or will have to manage is approximately 700,000 Mg. Studies have been conducted to evaluate the various alternatives for managing this material. This paper evaluates and summarizes the alternative of disposal as low-level waste (LLW). Results of the analysis indicate that UF{sub 6} needs to be converted to a more stable form, such as U{sub 3}O{sub 8}, before disposal as LLW. Estimates of the environmental impacts of disposal in a dry environment are within the currently applicable standards and regulations. Of the currently operating LLW disposal facilities, available information indicates that either of two DOE facilities--the Hanford Site or the Nevada Test Site--or a commercial facility--Envirocare of Utah--would be able to dispose of up to the entire DOE inventory of depleted UF{sub 6}.