Sample records for incorporating tritium control

  1. Incorporation of Tritium-labelled Thymidine in Bufo $female$ × Rana temporaria $male$ Hybrid Embryos

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

    TENCER, B.

    1961-04-01

    Two-cell stages of hybrid embryos resulting from the cross-fertilization of Bufo and Rana temporaria were incubated for 17 hrs in a medium containing tritium-labeled thymidine. The embryos were fixed by freeze-substitution and the incorporation of tritium studied by the radioautographic technique. The embryos stopped development at the late blastula stage. Labeling of desoxyribonucleic acid was demonstrated in morula as well as in blastula cells of the lethal hybrids. Tritium-labeled thymidine was shown to be incorporated into desoxyribonucleic acid 24 hr after development stopped, which suggests that the block in development was not due to the arrest of desoxyribonucleic acid synthesis.more » (C.H.)« less

  2. Calculated Energy Deposits from the Decay of Tritium and Other Radioisotopes Incorporated into Bacteria

    PubMed Central

    Bockrath, Richard; Person, Stanley; Funk, Fred

    1968-01-01

    Transmutation of the radioisotope tritium occurs with the production of a low energy electron, having a range in biological material similar to the dimensions of a bacterium. A computer program was written to determine the radiation dose distributions which may be expected within a bacterium as a result of tritium decay, when the isotope has been incorporated into specific regions of the bacterium. A nonspherical model bacterium was used, represented by a cylinder with hemispherical ends. The energy distributions resulting from a wide variety of simulated labeled regions were determined; the results suggested that the nuclear region of a bacterium receives on the average significantly different per decay doses, if the labeled regions were those conceivably produced by the incorporation of thymidine-3H, uracil-3H, or 3H-amino acids. Energy distributions in the model bacterium were also calculated for the decay of incorporated 14carbon, 35sulfur, and 32phosphorous. PMID:5678319

  3. Catabolism of Tritiated Thymidine by Aquatic Microbial Communities and Incorporation of Tritium into RNA and Protein †

    PubMed Central

    Brittain, Andrew M.; Karl, David M.

    1990-01-01

    The incorporation of tritiated thymidine by five microbial ecosystems and the distribution of tritium into DNA, RNA, and protein were determined. All microbial assemblages tested exhibited significant labeling of RNA and protein (i.e., nonspecific labeling), as determined by differential acid-base hydrolysis. Nonspecific labeling was greatest in sediment samples, for which ≥95% of the tritium was recovered with the RNA and protein fractions. The percentage of tritium recovered in the DNA fraction ranged from 15 to 38% of the total labeled macromolecules recovered. Nonspecific labeling was independent of both incubation time and thymidine concentration over very wide ranges. Four different RNA hydrolysis reagents (KOH, NaOH, piperidine, and enzymes) solubilized tritium from cold trichloroacetic acid precipitates. High-pressure liquid chromatography separation of piperidine hydrolysates followed by measurement of isolated monophosphates confirmed the labeling of RNA and indicated that tritium was recovered primarily in CMP and AMP residues. We also evaluated the specificity of [2-3H]adenine incorporation into adenylate residues in both RNA and DNA in parallel with the [3H]thymidine experiments and compared the degree of nonspecific labeling by [3H]adenine with that derived from [3H]thymidine. Rapid catabolism of tritiated thymidine was evaluated by determining the disappearance of tritiated thymidine from the incubation medium and the appearance of degradation products by high-pressure liquid chromatography separation of the cell-free medium. Degradation product formation, including that of both volatile and nonvolatile compounds, was much greater than the rate of incorporation of tritium into stable macromolecules. The standard degradation pathway for thymidine coupled with utilization of Krebs cycle intermediates for the biosynthesis of amino acids, purines, and pyrimidines readily accounts for the observed nonspecific labeling in environmental samples. PMID

  4. Method and apparatus for controlling accidental releases of tritium

    DOEpatents

    Galloway, T.R.

    1980-04-01

    An improvement is described in a tritium control system based on a catalytic oxidation reactor wherein accidental releases of tritium into room air are controlled by flooding the catalytic oxidation reactor with hydrogen when the tritium concentration in the room air exceeds a specified limit. The sudden flooding with hydrogen heats the catalyst to a high temperature within seconds, thereby greatly increasing the catalytic oxidation rate of tritium to tritiated water vapor. Thus, the catalyst is heated only when needed. In addition to the heating effect, the hydrogen flow also swamps the tritium and further reduces the tritium release. 1 fig.

  5. Method and apparatus for controlling accidental releases of tritium

    DOEpatents

    Galloway, Terry R. [Berkeley, CA

    1980-04-01

    An improvement in a tritium control system based on a catalytic oxidation reactor wherein accidental releases of tritium into room air are controlled by flooding the catalytic oxidation reactor with hydrogen when the tritium concentration in the room air exceeds a specified limit. The sudden flooding with hydrogen heats the catalyst to a high temperature within seconds, thereby greatly increasing the catalytic oxidation rate of tritium to tritiated water vapor. Thus, the catalyst is heated only when needed. In addition to the heating effect, the hydrogen flow also swamps the tritium and further reduces the tritium release.

  6. Tritium Mitigation/Control for Advanced Reactor System

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

    Sun, Xiaodong; Christensen, Richard; Saving, John P.

    A tritium removal facility, which is similar to the design used for tritium recovery in fusion reactors, is proposed in this study for fluoride-salt-cooled high-temperature reactors (FHRs) to result in a two-loop FHR design with the elimination of an intermediate loop. Using this approach, an economic benefit can potentially be obtained by removing the intermediate loop, while the safety concern of tritium release can be mitigated. In addition, an intermediate heat exchanger (IHX) that can yield a similar tritium permeation rate to the production rate of 1.9 Ci/day in a 1,000 MWe PWR needs to be designed to prevent themore » residual tritium that is not captured in the tritium removal system from escaping into the power cycle and ultimately the environment. The main focus of this study is to aid the mitigation of tritium permeation issue from the FHR primary side to significantly reduce the concentration of tritium in the secondary side and the process heat application side (if applicable). The goal of the research is to propose a baseline FHR system without the intermediate loop. The specific objectives to accomplish the goals are: To estimate tritium permeation behavior in FHRs; To design a tritium removal system for FHRs; To meet the same tritium permeation level in FHRs as the tritium production rate of 1.9 Ci/day in 1,000 MWe PWRs; To demonstrate economic benefits of the proposed FHR system via comparing with the three-loop FHR system. The objectives were accomplished by designing tritium removal facilities, developing a tritium analysis code, and conducting an economic analysis. In the fusion reactor community, tritium extraction has been widely investigated and researched. Borrowing the experiences from the fusion reactor community, a tritium control and mitigation system was proposed. Based on mass transport theories, a tritium analysis code was developed, and the tritium behaviors were analyzed using the developed code. Tritium removal facilities were

  7. Tritium labeling of amino acids and peptides with liquid and solid tritium

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

    Souers, P.C.; Coronado, P.R.; Peng, C.T.

    Amino acids and peptides were labeled with liquid and solid tritium at 21/degree/K and 9/degree/K. At these low temperatures radiation degradation is minimal, and tritium incorporation increases with tritium concentration and exposure time. Ring saturation in L-phenylalanine does not occur. Peptide linkage in oligopeptides is stable toward tritium. Deiodination in 3-iodotyrosine and 3,5-diiodotyrosine occurs readily and proceeds in steps by losing one iodine atom at a time. Nickel and noble metal supported catalysts when used as supports for dispersion of the substrate promote tritium labeling at 21 K. Our study shows that both liquid and solid tritiums are potentially usefulmore » agents for labeling peptides and proteins.« less

  8. Role of soil-to-leaf tritium transfer in controlling leaf tritium dynamics: Comparison of experimental garden and tritium-transfer model results.

    PubMed

    Ota, Masakazu; Kwamena, Nana-Owusua A; Mihok, Steve; Korolevych, Volodymyr

    2017-11-01

    Environmental transfer models assume that organically-bound tritium (OBT) is formed directly from tissue-free water tritium (TFWT) in environmental compartments. Nevertheless, studies in the literature have shown that measured OBT/HTO ratios in environmental samples are variable and generally higher than expected. The importance of soil-to-leaf HTO transfer pathway in controlling the leaf tritium dynamics is not well understood. A model inter-comparison of two tritium transfer models (CTEM-CLASS-TT and SOLVEG-II) was carried out with measured environmental samples from an experimental garden plot set up next to a tritium-processing facility. The garden plot received one of three different irrigation treatments - no external irrigation, irrigation with low tritium water and irrigation with high tritium water. The contrast between the results obtained with the different irrigation treatments provided insights into the impact of soil-to-leaf HTO transfer on the leaf tritium dynamics. Concentrations of TFWT and OBT in the garden plots that were not irrigated or irrigated with low tritium water were variable, responding to the arrival of the HTO-plume from the tritium-processing facility. In contrast, for the plants irrigated with high tritium water, the TFWT concentration remained elevated during the entire experimental period due to a continuous source of high HTO in the soil. Calculated concentrations of OBT in the leaves showed an initial increase followed by quasi-equilibration with the TFWT concentration. In this quasi-equilibrium state, concentrations of OBT remained elevated and unchanged despite the arrivals of the plume. These results from the model inter-comparison demonstrate that soil-to-leaf HTO transfer significantly affects tritium dynamics in leaves and thereby OBT/HTO ratio in the leaf regardless of the atmospheric HTO concentration, only if there is elevated HTO concentrations in the soil. The results of this work indicate that assessment models

  9. Export Control Requirements for Tritium Processing Design and R&D

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

    Hollis, William Kirk; Maynard, Sarah-Jane Wadsworth

    This document will address requirements of export control associated with tritium plant design and processes. Los Alamos National Laboratory has been working in the area of tritium plant system design and research and development (R&D) since the early 1970’s at the Tritium Systems Test Assembly (TSTA). This work has continued to the current date with projects associated with the ITER project and other Office of Science Fusion Energy Science (OS-FES) funded programs. ITER is currently the highest funding area for the DOE OS-FES. Although export control issues have been integrated into these projects in the past a general guidance documentmore » has not been available for reference in this area. To address concerns with currently funded tritium plant programs and assist future projects for FES, this document will identify the key reference documents and specific sections within related to tritium research. Guidance as to the application of these sections will be discussed with specific detail to publications and work with foreign nationals.« less

  10. Export Control Requirements for Tritium Processing Design and R&D

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

    Hollis, William Kirk; Maynard, Sarah-Jane Wadsworth

    2015-10-30

    This document will address requirements of export control associated with tritium plant design and processes. Los Alamos National Laboratory has been working in the area of tritium plant system design and research and development (R&D) since the early 1970’s at the Tritium Systems Test Assembly (TSTA). This work has continued to the current date with projects associated with the ITER project and other Office of Science Fusion Energy Science (OS-FES) funded programs. ITER is currently the highest funding area for the DOE OS-FES. Although export control issues have been integrated into these projects in the past a general guidance documentmore » has not been available for reference in this area. To address concerns with currently funded tritium plant programs and assist future projects for FES, this document will identify the key reference documents and specific sections within related to tritium research. Guidance as to the application of these sections will be discussed with specific detail to publications and work with foreign nationals.« less

  11. Study on the temperature control mechanism of the tritium breeding blanket for CFETR

    NASA Astrophysics Data System (ADS)

    Liu, Changle; Qiu, Yang; Zhang, Jie; Zhang, Jianzhong; Li, Lei; Yao, Damao; Li, Guoqiang; Gao, Xiang; Wu, Songtao; Wan, Yuanxi

    2017-12-01

    The Chinese fusion engineering testing reactor (CFETR) will demonstrate tritium self- sufficiency using a tritium breeding blanket for the tritium fuel cycle. The temperature control mechanism (TCM) involves the tritium production of the breeding blanket and has an impact on tritium self-sufficiency. In this letter, the CFETR tritium target is addressed according to its missions. TCM research on the neutronics and thermal hydraulics issues for the CFETR blanket is presented. The key concerns regarding the blanket design for tritium production under temperature field control are depicted. A systematic theory on the TCM is established based on a multiplier blanket model. In particular, a closed-loop method is developed for the mechanism with universal function solutions, which is employed in the CFETR blanket design activity for tritium production. A tritium accumulation phenomenon is found close to the coolant in the blanket interior, which has a very important impact on current blanket concepts using water coolant inside the blanket. In addition, an optimal tritium breeding ratio (TBR) method based on the TCM is proposed, combined with thermal hydraulics and finite element technology. Meanwhile, the energy gain factor is adopted to estimate neutron heat deposition, which is a key parameter relating to the blanket TBR calculations, considering the structural factors. This work will benefit breeding blanket engineering for the CFETR reactor in the future.

  12. Tritium Control and Capture in Salt-Cooled Fission and Fusion Reactors: Status, Challenges, and Path Forward

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

    Forsberg, Charles W.; Lam, Stephen; Carpenter, David M.

    Three advanced nuclear power systems use liquid salt coolants that generate tritium and thus face the common challenges of containing and capturing tritium to prevent its release to the environment. The fluoride salt–cooled high-temperature reactor (FHR) uses clean fluoride salt coolants and the same graphite-matrix coated-particle fuel as high-temperature gas-cooled reactors. Molten salt reactors (MSRs) dissolve the fuel in a fluoride or chloride salt with release of fission product tritium into the salt. In most FHR and MSR systems, the baseline salts contain lithium where isotopically separated 7Li is proposed to minimize tritium production from neutron interactions with the salt.more » The Chinese Academy of Sciences plans to start operation of a 2-MW(thermal) molten salt test reactor by 2020. For high-magnetic-field fusion machines, the use of lithium enriched in 6Li is proposed to maximize tritium generation—the fuel for a fusion machine. Advances in superconductors that enable higher power densities may require the use of molten lithium salts for fusion blankets and as coolants. Recent technical advances in these three reactor classes have resulted in increased government and private interest and the beginning of a coordinated effort to address the tritium control challenges in 700°C liquid salt systems. In this paper, we describe characteristics of salt-cooled fission and fusion machines, the basis for growing interest in these technologies, tritium generation in molten salts, the environment for tritium capture, models for high-temperature tritium transport in salt systems, alternative strategies for tritium control, and ongoing experimental work. Several methods to control tritium appear viable. Finally, limited experimental data are the primary constraint for designing efficient cost-effective methods of tritium control.« less

  13. Tritium Control and Capture in Salt-Cooled Fission and Fusion Reactors: Status, Challenges, and Path Forward

    DOE PAGES

    Forsberg, Charles W.; Lam, Stephen; Carpenter, David M.; ...

    2017-02-26

    Three advanced nuclear power systems use liquid salt coolants that generate tritium and thus face the common challenges of containing and capturing tritium to prevent its release to the environment. The fluoride salt–cooled high-temperature reactor (FHR) uses clean fluoride salt coolants and the same graphite-matrix coated-particle fuel as high-temperature gas-cooled reactors. Molten salt reactors (MSRs) dissolve the fuel in a fluoride or chloride salt with release of fission product tritium into the salt. In most FHR and MSR systems, the baseline salts contain lithium where isotopically separated 7Li is proposed to minimize tritium production from neutron interactions with the salt.more » The Chinese Academy of Sciences plans to start operation of a 2-MW(thermal) molten salt test reactor by 2020. For high-magnetic-field fusion machines, the use of lithium enriched in 6Li is proposed to maximize tritium generation—the fuel for a fusion machine. Advances in superconductors that enable higher power densities may require the use of molten lithium salts for fusion blankets and as coolants. Recent technical advances in these three reactor classes have resulted in increased government and private interest and the beginning of a coordinated effort to address the tritium control challenges in 700°C liquid salt systems. In this paper, we describe characteristics of salt-cooled fission and fusion machines, the basis for growing interest in these technologies, tritium generation in molten salts, the environment for tritium capture, models for high-temperature tritium transport in salt systems, alternative strategies for tritium control, and ongoing experimental work. Several methods to control tritium appear viable. Finally, limited experimental data are the primary constraint for designing efficient cost-effective methods of tritium control.« less

  14. History of 232-F, tritium extraction processing

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

    Blackburn, G.W.

    1994-08-01

    In 1950 the Atomic Energy Commission authorized the Savannah River Project principally for the production of tritium and plutonium-239 for use in thermonuclear weapons. 232-F was built as an interim facility in 1953--1954, at a cost of $3.9M. Tritium extraction operations began in October, 1955, after the reactor and separations startups. In July, 1957 a larger tritium facility began operation in 232-H. In 1958 the capacity of 232-H was doubled. Also, in 1957 a new task was assigned to Savannah River, the loading of tritium into reservoirs that would be actual components of thermonuclear weapons. This report describes the historymore » of 232-F, the process for tritium extraction, and the lessons learned over the years that were eventually incorporated into the new Replacement Tritium Facility.« less

  15. Tritium trick

    NASA Technical Reports Server (NTRS)

    Green, W. V.; Zukas, E. G.; Eash, D. T.

    1971-01-01

    Large controlled amounts of helium in uniform concentration in thick samples can be obtained through the radioactive decay of dissolved tritium gas to He3. The term, tritium trick, applies to the case when helium, added by this method, is used to simulate (n,alpha) production of helium in simulated hard flux radiation damage studies.

  16. The Reactions of Recoil Tritium with Anilides (in Japanese)

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

    OKAMOTO, Jiro; TSUCHIHASHI, Gen-ichi

    1961-01-01

    The distribution of tritium in some tritiated anilides (acetanilide, propionanilide, n-butylanilide, iso-butylanilide) which were produced by irradiation of mixed powder of anilides and lithium carbonate, were investigated. The tritium contents of the ortho-, meta-, and para-positions in the anilides were obtained by the activity measurement of some derivatives. The reactivities of ortho-position for tritium decreases in the order acetanilide, propionanilide, nbutylanilide, iso-butylanilide, perhaps because of steric interference of alkyl groups. The contents of incorporated tritium in alkyl groups were 13.2%, 31.7%, 31.1%, and 45.4%, for acetanilide, propionanilide, n-butylanilide, iso- butylanilide, respectively.

  17. Tritium well depth, tritium well time and sponge mechanism for reducing tritium retention

    NASA Astrophysics Data System (ADS)

    Deng, B. Q.; Li, Z. X.; Li, C. Y.; Feng, K. M.

    2011-07-01

    New simulation results are predicted in a fusion reactor operation process. They are somewhat similar to, but quite different from, the xenon poisoning effects resulting from fission-produced iodine during the restart-up process of a fission reactor. We obtained completely new results of tritium well depth and tritium well time in magnetic confinement fusion energy research area. This study is carried out to investigate the following: what will be the least amount of tritium storage required to start up a fusion reactor and how long the fusion reactor needs to be operated for achieving the tritium break-even during the initial start-up phase due to the finite tritium-breeding time, which is dependent on the tritium breeder, specific structure of the breeding zone, layout of the coolant flow pipes, tritium recovery scheme and applied extraction process, the tritium retention of plasma facing component (PFC) and other reactor components, unrecoverable tritium fraction in the breeder, leakage to the inertial gas container and the natural radioactive decay time constant. We describe these new issues and answer these problems by setting up and solving a set of equations, which are described by a dynamic subsystem model of tritium inventory evolution in a fusion experimental breeder (FEB). Reasonable results are obtained using our simulation model. It is found that the tritium well depth is about 0.319 kg and the tritium well time is approximately 235 full power operation days for the reference case of the designed FEB configuration, and it is also found that after one-year operation the tritium storage reaches 0.767 kg, which is more than the least amount of tritium storage required to start up another FEB-like fusion reactor. The results show that the tritium retention in the PFC is equivalent to 11.9% of tritium well depth that is fairly consistent with the result of 10-20% deduced from the integrated particle balance of European tokamaks. Based on our experimental

  18. Tritium release from SS316 under vacuum condition

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

    Torikai, Y.; Penzhorn, R.D.

    The plasma facing surface of the ITER vacuum vessel, partly made of low carbon austenitic stainless steel type 316L, will incorporate tritium during machine operation. In this paper the kinetics of tritium release from stainless steel type 316 into vacuum and into a noble gas stream are compared and modelled. Type 316 stainless steel specimens loaded with tritium either by exposure to 1.2 kPa HT at 573 K or submersion into liquid HTO at 298 K showed characteristic thin surface layers trapping tritium in concentrations far higher than those determined in the bulk. The evolution of the tritium depth profilemore » in the bulk during heating under vacuum was non-discernible from that of tritium liberated into a stream of argon. Only the relative amount of the two released tritium-species, i.e. HT or HTO, was different. Temperature-dependent depth profiles could be predicted with a one-dimensional diffusion model. Diffusion coefficients derived from fitting of the tritium release into an evacuated vessel or a stream of argon were found to be (1.4 ± 1.0)*10{sup -7} and (1.3 ± 0.9)*10{sup -9} cm{sup 2}/s at 573 and 423 K, respectively. Polished surfaces on type SS316 stainless steel inhibit considerably the thermal release rate of tritium.« less

  19. Vanadium hydride deuterium-tritium generator

    DOEpatents

    Christensen, Leslie D.

    1982-01-01

    A pressure controlled vanadium hydride gas generator to provide deuterium-tritium gas in a series of pressure increments. A high pressure chamber filled with vanadium-deuterium-tritium hydride is surrounded by a heater which controls the hydride temperature. The heater is actuated by a power controller which responds to the difference signal between the actual pressure signal and a programmed pressure signal.

  20. Reemission of Tritium from Tritium-Sorbed Molecular Sieve

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

    Cao Xiaohua; Cheng Guijun

    2005-07-15

    In handling of tritium-containing waste gas, tritium is oxidized to tritiated water and immobilized in a molecular sieve (MS), which is then disposed of as solid radioactive waste. So reemission of tritium from tritium-sorbed molecular sieve is concerned for tritium waste disposal. 4A, 5A and 10X MS were chosen for the tritium reemission test. The tritium-containing MS samples with specific activity of 3 GBq/g were prepared and the reemission coefficients of tritium from the three types of MS were determined. The effects of storage conditions of the MS on the reemission of tritium were examined. The results show that duringmore » two months of storage period, the reemission coefficients of 4A, 5A and 10X MS are (1.9{approx}5.5) x 10{sup -6} d{sup -1}.g{sup -1}. Among them, 5A MS has the largest reemission coefficient and 4A MS the smallest. The tritium released from tritium-sorbed MS is mostly in the form of HTO, only less than 1.2% of the tritium is in the form of HT. The atmosphere for storing tritium-sorbed MS has rather effect on reemission of tritium. The reemission coefficient in argon is lower than that in Ar+2%H{sub 2}.« less

  1. Vanadium hydride deuterium-tritium generator

    DOEpatents

    Christensen, L.D.

    1980-03-13

    A pressure controlled vanadium hydride gas generator was designed to provide deuterium-tritium gas in a series of pressure increments. A high pressure chamber filled with vanadium-deuterium-tritium hydride is surrounded by a heater which controls the hydride temperature. The heater is actuated by a power controller which responds to the difference signal between the actual pressure signal and a programmed pressure signal.

  2. Tritium dynamics in soils and plants grown under three irrigation regimes at a tritium processing facility in Canada.

    PubMed

    Mihok, S; Wilk, M; Lapp, A; St-Amant, N; Kwamena, N-O A; Clark, I D

    2016-03-01

    The dynamics of tritium released from nuclear facilities as tritiated water (HTO) have been studied extensively with results incorporated into regulatory assessment models. These models typically estimate organically bound tritium (OBT) for calculating public dose as OBT itself is rarely measured. Higher than expected OBT/HTO ratios in plants and soils are an emerging issue that is not well understood. To support the improvement of models, an experimental garden was set up in 2012 at a tritium processing facility in Pembroke, Ontario to characterize the circumstances under which high OBT/HTO ratios may arise. Soils and plants were sampled weekly to coincide with detailed air and stack monitoring. The design included a plot of native grass/soil, contrasted with sod and vegetables grown in barrels with commercial topsoil under natural rain and either low or high tritium irrigation water. Air monitoring indicated that the plume was present infrequently at concentrations of up to about 100 Bq/m(3) (the garden was not in a major wind sector). Mean air concentrations during the day on workdays (HTO 10.3 Bq/m(3), HT 5.8 Bq/m(3)) were higher than at other times (0.7-2.6 Bq/m(3)). Mean Tissue Free Water Tritium (TFWT) in plants and soils and OBT/HTO ratios were only very weakly or not at all correlated with releases on a weekly basis. TFWT was equal in soils and plants and in above and below ground parts of vegetables. OBT/HTO ratios in above ground parts of vegetables were above one when the main source of tritium was from high tritium irrigation water (1.5-1.8). Ratios were below one in below ground parts of vegetables when irrigated with high tritium water (0.4-0.6) and above one in vegetables rain-fed or irrigated with low tritium water (1.3-2.8). In contrast, OBT/HTO ratios were very high (9.0-13.5) when the source of tritium was mainly from the atmosphere. TFWT varied considerably through time as a result of SRBT's operations; OBT/HTO ratios showed no clear temporal

  3. TRITIUM BARRIER MATERIALS AND SEPARATION SYSTEMS FOR THE NGNP

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

    Sherman, S; Thad Adams, T

    2008-07-17

    Contamination of downstream hydrogen production plants or other users of high-temperature heat is a concern of the Next Generation Nuclear Plant (NGNP) Project. Due to the high operating temperatures of the NGNP (850-900 C outlet temperature), tritium produced in the nuclear reactor can permeate through heat exchangers to reach the hydrogen production plant, where it can become incorporated into process chemicals or the hydrogen product. The concentration limit for tritium in the hydrogen product has not been established, but it is expected that any future limit on tritium concentration will be no higher than the air and water effluent limitsmore » established by the NRC and the EPA. A literature survey of tritium permeation barriers, capture systems, and mitigation measures is presented and technologies are identified that may reduce the movement of tritium to the downstream plant. Among tritium permeation barriers, oxide layers produced in-situ may provide the most suitable barriers, though it may be possible to use aluminized surfaces also. For tritium capture systems, the use of getters is recommended, and high-temperature hydride forming materials such as Ti, Zr, and Y are suggested. Tritium may also be converted to HTO in order to capture it on molecular sieves or getter materials. Counter-flow of hydrogen may reduce the flux of tritium through heat exchangers. Recommendations for research and development work are provided.« less

  4. Tritium monitor and collection system

    DOEpatents

    Bourne, G.L.; Meikrantz, D.H.; Ely, W.E.; Tuggle, D.G.; Grafwallner, E.G.; Wickham, K.L.; Maltrud, H.R.; Baker, J.D.

    1992-01-14

    This system measures tritium on-line and collects tritium from a flowing inert gas stream. It separates the tritium from other non-hydrogen isotope contaminating gases, whether radioactive or not. The collecting portion of the system is constructed of various zirconium alloys called getters. These alloys adsorb tritium in any of its forms at one temperature and at a higher temperature release it as a gas. The system consists of four on-line getters and heaters, two ion chamber detectors, two collection getters, and two guard getters. When the incoming gas stream is valved through the on-line getters, 99.9% of it is adsorbed and the remainder continues to the guard getter where traces of tritium not collected earlier are adsorbed. The inert gas stream then exits the system to the decay chamber. Once the on-line getter has collected tritium for a predetermined time, it is valved off and the next on-line getter is valved on. Simultaneously, the first getter is heated and a pure helium purge is employed to carry the tritium from the getter. The tritium loaded gas stream is then routed through an ion chamber which measures the tritium activity. The ion chamber effluent passes through a collection getter that readsorbs the tritium and is removable from the system once it is loaded and is then replaced with a clean getter. Prior to removal of the collection getter, the system switches to a parallel collection getter. The effluent from the collection getter passes through a guard getter to remove traces of tritium prior to exiting the system. The tritium loaded collection getter, once removed, is analyzed by liquid scintillation techniques. The entire sequence is under computer control except for the removal and analysis of the collection getter. 7 figs.

  5. Tritium in Australian Precipitation: a 40 Year Record

    NASA Astrophysics Data System (ADS)

    Tadros, C. V.; Stone, D. J.; Hill, D. M.; Henderson-Sellers, A.

    2004-12-01

    Tritium, the radioisotope of hydrogen, directly incorporated into water molecules in the global hydrological system, is the most commonly used radioisotope indicator of groundwater recharge. Tritium in precipitation has been measured in Australia over the past 40 years, as an essential research tool in hydro-climate studies and to contribute to the Global Network for Isotopes in Precipitation (GNIP). Tritium, which as tritiated water (3H 1H O) is very mobile in the environment, delivers the benefit of tracing groundwater systems in a 10 - 20 year timeframe as a result of last century's atmospheric thermonuclear testing. The concentration of tritium in Australian precipitation reached a maximum level of 160 TU in 1963, during one of the most intense periods of nuclear testing. Our data reveal Australia experienced a `minor' bomb pulse compared to the Northern Hemisphere eg. in Ottawa, Canada a value of 6000 TU was recorded in 1963 for tritium in precipitation. From 1963 to 1980 we observe a rapid drop in the concentration of tritium, more than expected from natural decay, mainly due to the wash out of tritium into the oceans and groundwater. Since 1990 the levels of tritium have stabilised globally and regionally. Currently the levels of tritium in Australia have stabilised to 2 to 3 TU latitudinally across the continent, a factor of 10 lower than values observed at stations in the Northern Hemisphere. At present, levels of tritium in Australia appear to have ceased declining and our analyses suggest that today the tritium in precipitation is predominantly natural. We believe that it may be possible that the increased levels observed in the Northern Hemisphere, due to nuclear power generation [1] could `leak' into the Southern Hemisphere. This is important for research in Australia because it could hinder the exploitation of tritium in providing information on the origin and mechanism of recharge of shallow groundwaters and rivers [2]. 1. J.D. Happell, et al. A

  6. TRITIUM LABORATORY, TRA666, INTERIOR. MAIN FLOOR. CONTROL ROOM ENCLOSURE AT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    TRITIUM LABORATORY, TRA-666, INTERIOR. MAIN FLOOR. CONTROL ROOM ENCLOSURE AT CENTER OF VIEW. SIGN ABOVE DOOR SAYS "HYDRAULIC TEST FACILITY CONTROL ROOM." SIGN IN WINDOW SAYS "EATING AREA." "EVACUATION AND EMERGENCY INFORMATION" IS POSTED ON CABINET AT LEFT OF VIEW. INL NEGATIVE NO. HD30-2-3. Mike Crane, Photographer, 6/2001 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  7. Studying the spatial organization of membrane proteins by means of tritium stratigraphy: bacteriorhodopsin in purple membrane.

    PubMed

    Shishkov, A V; Ksenofontov, A L; Bogacheva, E N; Kordyukova, L V; Badun, G A; Alekseevsky, A V; Tsetlin, V I; Baratova, L A

    2002-05-15

    The topography of bacteriorhodopsin (bR) in situ was earlier studied by using the tritium bombardment approach [Eur. J. Biochem. 178 (1988) 123]. Now, having the X-ray crystallography data of bR at atom resolution [Proc. Natl. Acad. Sci. 95 (1998) 11673], we estimated the influence of membrane environment (lipid and protein) on tritium incorporation into amino acid residues forming transmembrane helices. We have determined the tritium flux attenuation coefficients for residues 10-29 of helix A. They turned out to be low (0.04+/-0.02 A(-1)) for residues adjacent to the lipid matrix, and almost fourfold higher (0.15+/-0.05 A(-1)) for those oriented to the neighboring transmembrane helices. We believe that tritium incorporation data could help modeling transmembrane segment arrangement in the membrane.

  8. Fixation of tritium in a highly stable polymer form

    DOEpatents

    Steinberg, Meyer; Colombo, Peter; Pruzansky, Jacob

    1977-01-01

    A method for the fixation of tritium comprising reacting tritiated water with calcium carbide to produce calcium hydroxide and tritiated acetylene, polymerizing the acetylene, and then incorporating the polymer in a solidifying matrix.

  9. Tritium Plasma Experiment Upgrade and Improvement of Surface Diagnostic Capabilities at STAR Facility for Enhancing Tritium and Nuclear PMI Sciences

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

    Shimada, M.; Taylor, C. N.; Pawelko, R. J.

    2016-04-01

    The Tritium Plasma Experiment (TPE) is a unique high-flux linear plasma device that can handle beryllium, tritium, and neutron-irradiated plasma facing materials, and is the only existing device dedicated to directly study tritium retention and permeation in neutron-irradiated materials with tritium [M. Shimada et.al., Rev. Sci. Instru. 82 (2011) 083503 and and M. Shimada, et.al., Nucl. Fusion 55 (2015) 013008]. The plasma-material-interaction (PMI) determines a boundary condition for diffusing tritium into bulk PFCs, and the tritium PMI is crucial for enhancing fundamental sciences that dictate tritium fuel cycles and safety and are high importance to an FNSF and DEMO. Recentlymore » the TPE has undergone major upgrades in its electrical and control systems. New DC power supplies and a new control center enable remote plasma operations from outside of the contamination area for tritium, minimizing the possible exposure risk with tritium and beryllium. We discuss the electrical upgrade, enhanced operational safety, improved plasma performance, and development of optical spectrometer system. This upgrade not only improves operational safety of the worker, but also enhances plasma performance to better simulate extreme plasma-material conditions expected in ITER, Fusion Nuclear Science Facility (FNSF), and Demonstration reactor (DEMO). This work was prepared for the U.S. Department of Energy, Office of Fusion Energy Sciences, under the DOE Idaho Field Office contract number DE-AC07-05ID14517.« less

  10. A novel atmospheric tritium sampling system

    NASA Astrophysics Data System (ADS)

    Qin, Lailai; Xia, Zhenghai; Gu, Shaozhong; Zhang, Dongxun; Bao, Guangliang; Han, Xingbo; Ma, Yuhua; Deng, Ke; Liu, Jiayu; Zhang, Qin; Ma, Zhaowei; Yang, Guo; Liu, Wei; Liu, Guimin

    2018-06-01

    The health hazard of tritium is related to its chemical form. Sampling different chemical forms of tritium simultaneously becomes significant. Here a novel atmospheric tritium sampling system (TS-212) was developed to collect the tritiated water (HTO), tritiated hydrogen (HT) and tritiated methane (CH3T) simultaneously. It consisted of an air inlet system, three parallel connected sampling channels, a hydrogen supply module, a methane supply module and a remote control system. It worked at air flow rate of 1 L/min to 5 L/min, with temperature of catalyst furnace at 200 °C for HT sampling and 400 °C for CH3T sampling. Conversion rates of both HT and CH3T to HTO were larger than 99%. The collecting efficiency of the two-stage trap sets for HTO was larger than 96% in 12 h working-time without being blocked. Therefore, the collected efficiencies of TS-212 are larger than 95% for tritium with different chemical forms in environment. Besides, the remote control system made sampling more intelligent, reducing the operator's work intensity. Based on the performance parameters described above, the TS-212 can be used to sample atmospheric tritium in different chemical forms.

  11. Tritium monitor

    DOEpatents

    Chastagner, Philippe

    1994-01-01

    A system for continuously monitoring the concentration of tritium in an aqueous stream. The system pumps a sample of the stream to magnesium-filled combustion tube which reduces the sample to extract hydrogen gas. The hydrogen gas is then sent to an isotope separation device where it is separated into two groups of isotopes: a first group of isotopes containing concentrations of deuterium and tritium, and a second group of isotopes having substantially no deuterium and tritium. The first group of isotopes containing concentrations of deuterium and tritium is then passed through a tritium detector that produces an output proportional to the concentration of tritium detected. Preferably, the detection system also includes the necessary automation and data collection equipment and instrumentation for continuously monitoring an aqueous stream.

  12. Evaluation of tritium release properties of advanced tritium breeders

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

    Hoshino, T.; Ochiai, K.; Edao, Y.

    2015-03-15

    Demonstration power plant (DEMO) fusion reactors require advanced tritium breeders with high thermal stability. Lithium titanate (Li{sub 2}TiO{sub 3}) advanced tritium breeders with excess Li (Li{sub 2+x}TiO{sub 3+y}) are stable in a reducing atmosphere at high temperatures. Although the tritium release properties of tritium breeders are documented in databases for DEMO blanket design, no in situ examination under fusion neutron (DT neutron) irradiation has been performed. In this study, a preliminary examination of the tritium release properties of advanced tritium breeders was performed, and DT neutron irradiation experiments were performed at the fusion neutronics source (FNS) facility in JAEA. Consideringmore » the tritium release characteristics, the optimum grain size after sintering is <5 μm. From the results of the optimization of granulation conditions, prototype Li{sub 2+x}TiO{sub 3+y} pebbles with optimum grain size (<5 μm) were successfully fabricated. The Li{sub 2+x}TiO{sub 3+y} pebbles exhibited good tritium release properties similar to the Li{sub 2}TiO{sub 3} pebbles. In particular, the released amount of HT gas for easier tritium handling was higher than that of HTO water. (authors)« less

  13. Tritium monitor

    DOEpatents

    Chastagner, P.

    1994-06-14

    A system is described for continuously monitoring the concentration of tritium in an aqueous stream. The system pumps a sample of the stream to magnesium-filled combustion tube which reduces the sample to extract hydrogen gas. The hydrogen gas is then sent to an isotope separation device where it is separated into two groups of isotopes: a first group of isotopes containing concentrations of deuterium and tritium, and a second group of isotopes having substantially no deuterium and tritium. The first group of isotopes containing concentrations of deuterium and tritium is then passed through a tritium detector that produces an output proportional to the concentration of tritium detected. Preferably, the detection system also includes the necessary automation and data collection equipment and instrumentation for continuously monitoring an aqueous stream. 1 fig.

  14. Development of a tritium recovery system from CANDU tritium removal facility

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

    Draghia, M.; Pasca, G.; Porcariu, F.

    2015-03-15

    The main purpose of the Tritium Recovery System (TRS) is to reduce to a maximum possible extent the release of tritium from the facility following a tritium release in confinement boundaries and also to have provisions to recover both elemental and vapors tritium from the purging gases during maintenance and components replacement from various systems processing tritium. This work/paper proposes a configuration of Tritium Recovery System wherein elemental tritium and water vapors are recovered in a separated, parallel manner. The proposed TRS configuration is a combination of permeators, a platinum microreactor (MR) and a trickle bed reactor (TBR) and consistsmore » of two branches: one branch for elemental tritium recovery from tritiated deuterium gas and the second one for tritium recovery from streams containing a significant amount of water vapours but a low amount, below 5%, of tritiated gas. The two branches shall work in a complementary manner in such a way that the bleed stream from the permeators shall be further processed in the MR and TBR in view of achieving the required decontamination level. A preliminary evaluation of the proposed TRS in comparison with state of the art tritium recovery system from tritium processing facilities is also discussed. (authors)« less

  15. 2009 EVALUATION OF TRITIUM REMOVAL AND MITIGATION TECHNOLOGIES FOR WASTEWATER TREATMENT

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

    LUECK KJ; GENESSE DJ; STEGEN GE

    2009-02-26

    Since 1995, a state-approved land disposal site (SALDS) has received tritium contaminated effluents from the Hanford Site Effluent Treatment Facility (ETF). Tritium in this effluent is mitigated by storage in slow moving groundwater to allow extended time for decay before the water reaches the site boundary. By this method, tritium in the SALDS is isolated from the general environment and human contact until it has decayed to acceptable levels. This report contains the 2009 update evaluation of alternative tritium mitigation techniques to control tritium in liquid effluents and groundwater at the Hanford site. A thorough literature review was completed andmore » updated information is provided on state-of-the-art technologies for control of tritium in wastewaters. This report was prepared to satisfy the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-026-07B (Ecology, EPA, and DOE 2007). Tritium separation and isolation technologies are evaluated periodically to determine their feasibility for implementation to control Hanford site liquid effluents and groundwaters to meet the Us. Code of Federal Regulations (CFR), Title 40 CFR 141.16, drinking water maximum contaminant level (MCL) for tritium of 20,000 pOll and/or DOE Order 5400.5 as low as reasonably achievable (ALARA) policy. Since the 2004 evaluation, there have been a number of developments related to tritium separation and control with potential application in mitigating tritium contaminated wastewater. These are primarily focused in the areas of: (1) tritium recycling at a commercial facility in Cardiff, UK using integrated tritium separation technologies (water distillation, palladium membrane reactor, liquid phase catalytic exchange, thermal diffusion), (2) development and demonstration of Combined Electrolysis Catalytic Exchange (CECE) using hydrogen/water exchange to separate tritium from water, (3) evaporation of tritium contaminated water for dispersion in the

  16. Tritium pellet injector for the tokamak fusion test reactor

    NASA Astrophysics Data System (ADS)

    Gouge, M. J.; Baylor, L. R.; Combs, S. K.; Fisher, P. W.; Foust, C. R.; Milora, S. L.

    The tritium pellet injector (TPI) for the Tokamak Fusion Test Reactor (TFTR) will provide a tritium pellet fueling capability with pellet speeds in the 1- to 3-km/s range for the TFTR deuterium-tritium (D-T) plasma phase. An existing deuterium pellet injector (DPI) was modified at Oak Ridge National Laboratory (ORNL) to provide a four-shot, tritium-compatible, pipe-gun configuration with three upgraded single-stage pneumatic guns and a two-stage light gas gun driver. The TPI was designed for frozen pellets ranging in size from 3 to 4 mm in diameter in arbitrarily programmable firing sequences at tritium pellet speeds up to approximately 1.5 km/s for the three single-stage drivers and 2.5 to 3 km/s for the two-stage driver. Injector operation is controlled by a programmable logic controller (PLC). The new pipe-gun injector assembly was installed in the modified DPI guard vacuum box, and modifications were also made to the internals of the DPI vacuum injection line, including a new pellet diagnostics package. Assembly of these modified parts with existing DPI components was then completed and the TPI was tested at ORNL with deuterium pellets. Results of the testing program at ORNL are described. The TPI has been installed and operated on TFTR in support of the FY-92 deuterium plasma run period. In 1993, the tritium pellet injector will be retrofitted with a D-T fuel manifold and tritium gloveboxes and integrated into TFTR tritium processing systems to provide full tritium pellet capability.

  17. 2001 Evaluation of Tritium Removal & Mitigation Technologies for Waste Water Treatment

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

    PENWELL, D.L.

    2001-06-01

    This report contains the 2001 biennial update evaluation of separation technologies and other mitigation techniques to control tritium in liquid effluents and groundwater at the Hanford site. A thorough literature review was completed, and national and international experts in the field of tritium separation and mitigation techniques were consulted. Current state-of-the-art technologies to address the control of tritium in wastewaters were identified and are described. This report was prepared to satisfy the Hanford Federal Facility Agreement and Consent Order Tri-Party Agreement, Milestone M-29-O5H (Ecology, EPA, and DOE 1996). Tritium separation and isolation technologies are evaluated on a biennial basis tomore » determine their feasibility for implementation for the control of Hanford site liquid effluents and groundwater to meet the US. Code of Federal Regulations (CFR), Title 40 CFR 141.16, drinking water maximum contaminant level (MCL) for tritium of 0.02 {mu} Ci/l ({approx}2 parts per quadrillion [10{sup -15}]) and/or DOE Order 5400.5 as low as reasonably achievable (ALARA) policy The objectives of this evaluation were to (1) status the development of potentially viable tritium separations technologies with regard to reducing tritium concentrations in current Hanford site process waters and existing groundwater to MCL levels and (2) status control methods to prevent the flow of tritiated water at concentrations greater than the MCL to the environment. Current tritium releases are in compliance with applicable US Environmental Protection Agency, Washington State Department of Ecology, and U.S. Department of Energy requirements under the Tri-Party Agreement. Advances in technologies for the separation of tritium from wastewater since the 1999 Hanford Site evaluation report include: (1) construction and testing of the Combined Industrial Reforming and Catalytic Exchange (CIRCE) Prototype Plant by Atomic Energy Canada Limited (AECL). The plant has a stage

  18. Behaviour of tritium in the vacuum vessel of JT-60U

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

    Kobayashi, K.; Miya, N.; Ikeda, Y.

    2015-03-15

    The disassembly of the JT-60U torus started in 2010 after 18 years of deuterium plasma operations. The vessel is made of Inconel 625. Therefore, it was very important to study the hydrogen isotope (particularly tritium) behavior in Inconel 625 from the viewpoint of the clearance procedure. Inconel 625 specimen was exposed to the D{sub 2} (92.8 %) - T{sub 2} (7.2 %) gas mixture at 573 K for 5 hours. The tritium release from the specimen at 298 K was controlled for about 1 year. After that a part of tritium remaining in the specimen was released by heating upmore » to 1073 K. Other part of tritium trapped in the specimen was measured by chemical etching method. Most of the chemical form of the released tritium was HTO. The contaminated specimen by tritium was released continuously the diffusible tritium under the ambient condition. In the tritium release experiment, the amount of desorbed tritium was about 99% during 1 year. It was considered that the tritium in Inconel 625 was released easily.« less

  19. Tritium levels in milk in the vicinity of chronic tritium releases.

    PubMed

    Le Goff, P; Guétat, Ph; Vichot, L; Leconte, N; Badot, P M; Gaucheron, F; Fromm, M

    2016-01-01

    Tritium is the radioactive isotope of hydrogen. It can be integrated into most biological molecules. Even though its radiotoxicity is weak, the effects of tritium can be increased following concentration in critical compartments of living organisms. For a better understanding of tritium circulation in the environment and to highlight transfer constants between compartments, we studied the tritiation of different agricultural matrices chronically exposed to tritium. Milk is one of the most frequently monitored foodstuffs in the vicinity of points known for chronic release of radionuclides firstly because dairy products find their way into most homes but also because it integrates deposition over large areas at a local scale. It is a food which contains all the main nutrients, especially proteins, carbohydrates and lipids. We thus studied the tritium levels of milk in chronic exposure conditions by comparing the tritiation of the main hydrogenated components of milk, first, component by component, then, sample by sample. Significant correlations were found between the specific activities of drinking water and free water of milk as well as between the tritium levels of cattle feed dry matter and of the main organic components of milk. Our findings stress the importance of the metabolism on the distribution of tritium in the different compartments. Overall, dilution of hydrogen in the environmental compartments was found to play an important role dimming possible isotopic effects even in a food chain chronically exposed to tritium. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Comparison of the structures of free and ribosome-bound tRNAPhe by using slow tritium exchange.

    PubMed Central

    Farber, N; Cantor, C R

    1980-01-01

    The rate of incorporation of tritium from the solvent into the C-8 position of purines in RNA is markedly sensitive to the microenvironment. This slow tritium exchange reaction has been used to study the structure and interactions of yeast tRNAPhe bound to poly(U)-programed tight-couple 70S ribosomes of Escherichia coli. The tritium incorporation into specific sites of the tRNA was determined by enzymatic digestion and measurement of the specific activity of each of the isolated radioactive fragments. Ribosome binding leads to marked suppression in the exchange rate of a number of fragments. This delineates extensive regions of tRNA-ribosome contact. No change in exchange rates is seen for fragments from the corner of the molecule, indicating that this region of bound tRNA is readily accessible to the solvent. Ribosome binding results in an enhanced exchange rate at the T loop. This appears to be the result of a conformational change that is most likely an unfolding of the T and D loops. Additional tritium exchange reactions suggest this conformational change is induced by ribosomes and not by messenger. PMID:7001473

  1. Continuous aqueous tritium monitor

    DOEpatents

    McManus, Gary J.; Weesner, Forrest J.

    1989-05-30

    An apparatus for a selective on-line determination of aqueous tritium concentration is disclosed. A moist air stream of the liquid solution being analyzed is passed through a permeation dryer where the tritium and moisture and selectively removed to a purge air stream. The purge air stream is then analyzed for tritium concentration, humidity, and temperature, which allows computation of liquid tritium concentration.

  2. Continuous aqueous tritium monitor

    DOEpatents

    McManus, G.J.; Weesner, F.J.

    1987-10-19

    An apparatus for a selective on-line determination of aqueous tritium concentration is disclosed. A moist air stream of the liquid solution being analyzed is passed through a permeation dryer where the tritium and moisture are selectively removed to a purge air stream. The purge air stream is then analyzed for tritium concentration, humidity, and temperature, which allows computation of liquid tritium concentration. 2 figs.

  3. Carbon-13 and carbon-14 labeled dabigatran etexilate and tritium labeled dabigatran.

    PubMed

    Latli, Bachir; Kiesling, Ralf; Aßfalg, Stefan; Chevliakov, Max; Hrapchak, Matt; Campbell, Scot; Gonnella, Nina; Busacca, Carl A; Senanayake, Chris H

    2016-12-01

    Dabigatran etexilate or pradaxa, a novel oral anticoagulant, is a reversible, competitive, direct thrombin inhibitor. It is used to prevent strokes in patients with atrial fibrillation and the formation of blood clots in the veins (deep venous thrombosis) in adults who have had an operation to replace a hip or a knee. Pradaxa is the only novel oral anticoagulant available with both proven superiority to warfarin and a specific reversal agent for use in rare emergency situations. The detailed description of the synthesis of carbon-13 and carbon-14 labeled dabigatran etexilate, and tritium labeled dabigatran is described. The synthesis of carbon-13 dabigatran etexilate was accomplished in eight steps and in 6% overall yield starting from aniline- 13 C 6 . Ethyl bromoacetate-1- 14 C was the reagent of choice in the synthesis of carbon-14 labeled dabigatran etexilate in six steps and 17% overall yield. Tritium labeled dabigatran was prepared using either direct tritium incorporation under Crabtree's catalytic conditions or tritium-dehalogenation of a diiodo-precursor of dabigatran. Copyright © 2016 John Wiley & Sons, Ltd.

  4. Tritium target manufacturing for use in accelerators

    NASA Astrophysics Data System (ADS)

    Bach, P.; Monnin, C.; Van Rompay, M.; Ballanger, A.

    2001-07-01

    As a neutron tube manufacturer, SODERN is now in charge of manufacturing tritium targets for accelerators, in cooperation with CEA/DAM/DTMN in Valduc. Specific deuterium and tritium targets are manufactured on request, according to the requirements of the users, starting from titanium target on copper substrate, and going to more sophisticated devices. A wide range of possible uses is covered, including thin targets for neutron calibration, thick targets with controlled loading of deuterium and tritium, rotating targets for higher lifetimes, or large size rotating targets for accelerators used in boron neutron therapy. Activity of targets lies in the 1 to 1000 Curie, diameter of targets being up to 30 cm. Special targets are also considered, including surface layer targets for lowering tritium desorption under irradiation, or those made from different kinds of occluders such as titanium, zirconium, erbium, scandium, with different substrates. It is then possible to optimize either neutron output, or lifetime and stability, or thermal behavior.

  5. Production of highly tritiated water for tritium exposure studies

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

    Muirhead, C.; Pilatzke, K.; Tripple, A.

    2015-03-15

    Tritium Facility staff at Chalk River Laboratories (CRL) have successfully prepared highly tritiated water for use in radiation resistance of PEM (Proton Exchange Membrane-based)electrolyser membrane. The goal of System A was to convert a known amount of elemental tritium (HT) into tritiated water vapour using a copper(II) oxide bed, and to condense the tritiated water vapour into a known amount of chilled heavy water (D{sub 2}O). The conversion and capture of tritium using this system is close to 100%. The goal of System B was to transfer tritiated water from the containment vessel to an exposure vessel (experiment) in amore » controlled and safe manner. System B is based on the pushing of D{sub 2}0 with low-pressure argon carrier gas to a calibrated volume and then to the exposure vessel. A method for delivering a known and controlled amount of tritiated water has been successfully demonstrated at CRL. Using both systems Tritium Facility staff have made and distributed highly tritiated water in a safe and controlled manner. This paper focuses on how the tritiated water was produced and dispensed to the experiment.« less

  6. Improvement of tritium accountancy technology for ITER fuel cycle safety enhancement

    NASA Astrophysics Data System (ADS)

    O'hira, S.; Hayashi, T.; Nakamura, H.; Kobayashi, K.; Tadokoro, T.; Nakamura, H.; Itoh, T.; Yamanishi, T.; Kawamura, Y.; Iwai, Y.; Arita, T.; Maruyama, T.; Kakuta, T.; Konishi, S.; Enoeda, M.; Yamada, M.; Suzuki, T.; Nishi, M.; Nagashima, T.; Ohta, M.

    2000-03-01

    In order to improve the safe handling and control of tritium for the ITER fuel cycle, effective in situ tritium accounting methods have been developed at the Tritium Process Laboratory in the Japan Atomic Energy Research Institute under one of the ITER-EDA R&D tasks. The remote and multilocation analysis of process gases by an application of laser Raman spectroscopy developed and tested could provide a measurement of hydrogen isotope gases with a detection limit of 0.3 kPa analytical periods of 120 s. An in situ tritium inventory measurement by application of a `self-assaying' storage bed with 25 g tritium capacity could provide a measurement with the required detection limit of less than 1% and a design proof of a bed with 100 g tritium capacity.

  7. Oxidative Tritium Decontamination System

    DOEpatents

    Gentile, Charles A. , Guttadora, Gregory L. , Parker, John J.

    2006-02-07

    The Oxidative Tritium Decontamination System, OTDS, provides a method and apparatus for reduction of tritium surface contamination on various items. The OTDS employs ozone gas as oxidizing agent to convert elemental tritium to tritium oxide. Tritium oxide vapor and excess ozone gas is purged from the OTDS, for discharge to atmosphere or transport to further process. An effluent stream is subjected to a catalytic process for the decomposition of excess ozone to diatomic oxygen. One of two configurations of the OTDS is employed: dynamic apparatus equipped with agitation mechanism and large volumetric capacity for decontamination of light items, or static apparatus equipped with pressurization and evacuation capability for decontamination of heavier, delicate, and/or valuable items.

  8. Tritium

    DTIC Science & Technology

    2011-11-01

    fusion energy -production processes of the particular type of reactor using a lithium (Li) blanket or related alloys such as the Pb-17Li eutectic. As such, tritium breeding is intimately connected with energy production, thermal management, radioactivity management, materials properties, and mechanical structures of any plausible future large-scale fusion power reactor. JASON is asked to examine the current state of scientific knowledge and engineering practice on the physical and chemical bases for large-scale tritium

  9. Using the Tritium Plasma Experiment to evaluate ITER PFC safety

    NASA Astrophysics Data System (ADS)

    Longhurst, Glen R.; Anderl, Robert A.; Bartlit, John R.; Causey, Rion A.; Haines, John R.

    The Tritium Plasma Experiment was assembled at Sandia National Laboratories, Livermore to investigate interactions between dense plasmas at low energies and plasma-facing component materials. This apparatus has the unique capability of replicating plasma conditions in a tokamak divertor with particle flux densities of 2 x 10(exp 19) ions/((sq cm)(s)) and a plasma temperature of about 15 eV using a plasma that includes tritium. With the closure of the Tritium Research Laboratory at Livermore, the experiment was moved to the Tritium Systems Test Assembly facility at Los Alamos National Laboratory. An experimental program has been initiated there using the Tritium Plasma Experiment to examine safety issues related to tritium in plasma-facing components, particularly the ITER divertor. Those issues include tritium retention and release characteristics, tritium permeation rates and transient times to coolant streams, surface modification and erosion by the plasma, the effects of thermal loads and cycling, and particulate production. A considerable lack of data exists in these areas for many of the materials, especially beryllium, being considered for use in ITER. Not only will basic material behavior with respect to safety issues in the divertor environment be examined, but innovative techniques for optimizing performance with respect to tritium safety by material modification and process control will be investigated. Supplementary experiments will be carried out at the Idaho National Engineering Laboratory and Sandia National Laboratory to expand and clarify results obtained on the Tritium Plasma Experiment.

  10. Development of a tritium monitor combined with an electrochemical tritium pump using a proton conducting oxide

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

    Tanaka, M.; Sugiyama, T.

    2015-03-15

    The detection of low level tritium is one of the key issues for tritium management in tritium handling facilities. Such a detection can be performed by tritium monitors based on proton conducting oxide technique. We tested a tritium monitoring system composed of a commercial proportional counter combined with an electrochemical hydrogen pump equipped with CaZr{sub 0.9}In{sub 0.1}O{sub 3-α} as proton conducting oxide. The hydrogen pump operated at 973 K under electrolysis conditions using tritiated water vapor (HTO). The proton conducting oxide extracts tritium molecules (HT) from HTO and tritium concentration is measured by the proportional counter. The advantage of themore » proposed tritium monitoring system is that it is able to convert HTO into molecular hydrogen.« less

  11. Tritium containing polymers having a polymer backbone substantially void of tritium

    DOEpatents

    Jensen, George A.; Nelson, David A.; Molton, Peter M.

    1992-01-01

    A radioluminescent light source comprises a solid mixture of a phosphorescent substance and a tritiated polymer. The solid mixture forms a solid mass having length, width, and thickness dimensions, and is capable of self-support. In one aspect of the invention, the phosphorescent substance comprises solid phosphor particles supported or surrounded within a solid matrix by a tritium containing polymer. The tritium containing polymer comprises a polymer backbone which is essentially void of tritium.

  12. Tritium containing polymers having a polymer backbone substantially void of tritium

    DOEpatents

    Jensen, G.A.; Nelson, D.A.; Molton, P.M.

    1992-03-31

    A radioluminescent light source comprises a solid mixture of a phosphorescent substance and a tritiated polymer. The solid mixture forms a solid mass having length, width, and thickness dimensions, and is capable of self-support. In one aspect of the invention, the phosphorescent substance comprises solid phosphor particles supported or surrounded within a solid matrix by a tritium containing polymer. The tritium containing polymer comprises a polymer backbone which is essentially void of tritium. 2 figs.

  13. Silicon Carbide as a tritium permeation barrier in tungsten plasma-facing components

    NASA Astrophysics Data System (ADS)

    Wright, G. M.; Durrett, M. G.; Hoover, K. W.; Kesler, L. A.; Whyte, D. G.

    2015-03-01

    The control of tritium inventory is of great importance in future fusion reactors, not only from a safety standpoint but also to maximize a reactor's efficiency. Due to the high mobility of hydrogenic species in tungsten (W) one concern is the loss of tritium from the system via permeation through the tungsten plasma-facing components (PFC). This can lead to loss of tritium through the cooling channels of the wall thereby mandating tritium monitoring and recovery methods for the cooling system of the first wall. The permeated tritium is then out of the fuel cycle and cannot contribute to energy production until it is recovered and recycled into the system.

  14. Drum bubbler tritium processing system

    DOEpatents

    Rule, K.; Gettelfinger, G.; Kivler, P.

    1999-08-17

    A method is described for separating tritium oxide from a gas stream containing tritium oxide. The gas stream containing tritium oxide is fed into a container of water having a head space above the water. The tritium oxide is separated by bubbling the gas stream containing tritium oxide through the container of water and removing gas from the container head space above the water. Thereafter, the gas from the head space is dried to remove water vapor from the gas, and the water vapor is recycled to the container of water. 2 figs.

  15. Tritium waste package

    DOEpatents

    Rossmassler, Rich; Ciebiera, Lloyd; Tulipano, Francis J.; Vinson, Sylvester; Walters, R. Thomas

    1995-01-01

    A containment and waste package system for processing and shipping tritium xide waste received from a process gas includes an outer drum and an inner drum containing a disposable molecular sieve bed (DMSB) seated within outer drum. The DMSB includes an inlet diffuser assembly, an outlet diffuser assembly, and a hydrogen catalytic recombiner. The DMSB absorbs tritium oxide from the process gas and converts it to a solid form so that the tritium is contained during shipment to a disposal site. The DMSB is filled with type 4A molecular sieve pellets capable of adsorbing up to 1000 curies of tritium. The recombiner contains a sufficient amount of catalyst to cause any hydrogen add oxygen present in the process gas to recombine to form water vapor, which is then adsorbed onto the DMSB.

  16. Tritium protective clothing

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

    Fuller, T. P.; Easterly, C. E.

    Occupational exposures to radiation from tritium received at present nuclear facilities and potential exposures at future fusion reactor facilities demonstrate the need for improved protective clothing. Important areas relating to increased protection factors of tritium protective ventilation suits are discussed. These areas include permeation processes of tritium through materials, various tests of film permeability, selection and availability of suit materials, suit designs, and administrative procedures. The phenomenological nature of film permeability calls for more standardized and universal test methods, which would increase the amount of directly useful information on impermeable materials. Improvements in suit designs could be expedited and bettermore » communicated to the health physics community by centralizing devlopmental equipment, manpower, and expertise in the field of tritium protection to one or two authoritative institutions.« less

  17. Tritium resources available for fusion reactors

    NASA Astrophysics Data System (ADS)

    Kovari, M.; Coleman, M.; Cristescu, I.; Smith, R.

    2018-02-01

    The tritium required for ITER will be supplied from the CANDU production in Ontario, but while Ontario may be able to supply 8 kg for a DEMO fusion reactor in the mid-2050s, it will not be able to provide 10 kg at any realistic starting time. The tritium required to start DEMO will depend on advances in plasma fuelling efficiency, burnup fraction, and tritium processing technology. It is in theory possible to start up a fusion reactor with little or no tritium, but at an estimated cost of 2 billion per kilogram of tritium saved, it is not economically sensible. Some heavy water reactor tritium production scenarios with varying degrees of optimism are presented, with the assumption that only Canada, the Republic of Korea, and Romania make tritium available to the fusion community. Results for the tritium available for DEMO in 2055 range from zero to 30 kg. CANDU and similar heavy water reactors could in theory generate additional tritium in a number of ways: (a) adjuster rods containing lithium could be used, giving 0.13 kg per year per reactor; (b) a fuel bundle with a burnable absorber has been designed for CANDU reactors, which might be adapted for tritium production; (c) tritium production could be increased by 0.05 kg per year per reactor by doping the moderator with lithium-6. If a fusion reactor is started up around 2055, governments in Canada, Argentina, China, India, South Korea and Romania will have the opportunity in the years leading up to that to take appropriate steps: (a) build, refurbish or upgrade tritium extraction facilities; (b) extend the lives of heavy water reactors, or build new ones; (c) reduce tritium sales; (d) boost tritium production in the remaining heavy water reactors. All of the alternative production methods considered have serious economic and regulatory drawbacks, and the risk of diversion of tritium or lithium-6 would also be a major concern. There are likely to be serious problems with supplying tritium for future

  18. Tritium waste package

    DOEpatents

    Rossmassler, R.; Ciebiera, L.; Tulipano, F.J.; Vinson, S.; Walters, R.T.

    1995-11-07

    A containment and waste package system for processing and shipping tritium oxide waste received from a process gas includes an outer drum and an inner drum containing a disposable molecular sieve bed (DMSB) seated within the outer drum. The DMSB includes an inlet diffuser assembly, an outlet diffuser assembly, and a hydrogen catalytic recombiner. The DMSB absorbs tritium oxide from the process gas and converts it to a solid form so that the tritium is contained during shipment to a disposal site. The DMSB is filled with type 4A molecular sieve pellets capable of adsorbing up to 1000 curies of tritium. The recombiner contains a sufficient amount of catalyst to cause any hydrogen and oxygen present in the process gas to recombine to form water vapor, which is then adsorbed onto the DMSB. 1 fig.

  19. Radionuclide Basics: Tritium

    EPA Pesticide Factsheets

    Tritium is a hydrogen atom that has two neutrons in the nucleus and one proton. It is radioactive and behaves like other forms of hydrogen in the environment. Tritium is produced naturally in the upper atmosphere and as a byproduct of nuclear fission.

  20. Laser-assisted isotope separation of tritium

    DOEpatents

    Herman, Irving P.; Marling, Jack B.

    1983-01-01

    Methods for laser-assisted isotope separation of tritium, using infrared multiple photon dissociation of tritium-bearing products in the gas phase. One such process involves the steps of (1) catalytic exchange of a deuterium-bearing molecule XYD with tritiated water DTO from sources such as a heavy water fission reactor, to produce the tritium-bearing working molecules XYT and (2) photoselective dissociation of XYT to form a tritium-rich product. By an analogous procedure, tritium is separated from tritium-bearing materials that contain predominately hydrogen such as a light water coolant from fission or fusion reactors.

  1. EFFECTS OF TRITIUM EXPOSURE ON UHMW-PE, PTFE, AND VESPEL

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

    Clark, E; Kirk Shanahan, K

    2006-05-31

    Samples of three polymers, Ultra-High Molecular Weight Polyethylene (UHMW-PE), polytetrafluoroethylene (PTFE, also known as Teflon{reg_sign}), and Vespel{reg_sign} polyimide were exposed to 1 atmosphere of tritium gas at ambient temperature for varying times up to 2.3 years in closed containers. Sample mass and size measurements (to calculate density), spectra-colorimetry, dynamic mechanical analysis (DMA), and Fourier-transform infrared spectroscopy (FT-IR) were employed to characterize the effects of tritium exposure on these samples. Changes of the tritium exposure gas itself were characterized at the end of exposure by measuring total pressure and by mass spectroscopic analysis of the gas composition. None of the polymersmore » exhibited significant changes of density. The color of initially white UHMW-PE and PTFE dramatically darkened to the eye and the color also significantly changed as measured by colorimetry. The bulk of UHMW-PE darkened just like the external surfaces, however the fracture surface of PTFE appeared white compared to the PTFE external surfaces. The white interior could have been formed while the sample was breaking or could reflect the extra tritium dose at the surface directly from the gas. The dynamic mechanical response of UHMW-PE was typical of radiation effects on polymers- an initial stiffening (increased storage modulus) and reduction of viscous behavior after three months exposure, followed by lowering of the storage modulus after one year exposure and longer. The storage modulus of PTFE increased through about nine months tritium exposure, then the samples became too weak to handle or test using DMA. Characterization of Vespel{reg_sign} using DMA was problematic--sample-to-sample variations were significant and no systematic change with tritium exposure could be discerned. Isotopic exchange and incorporation of tritium into UHMW-PE (exchanging for protium) and into PTFE (exchanging for fluorine) was observed by FT-IR using an

  2. Fabrication of light water reactor tritium targets

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

    Pilger, J.P.

    1991-11-01

    The mission of the Fabrication Development Task of the Tritium Target Development Project is: to produce a documented technology basis, including specifications and procedures for target rod fabrication; to demonstrate that light water tritium targets can be manufactured at a rate consistent with tritium production requirements; and to develop quality control methods to evaluate target rod components and assemblies, and establish correlations between evaluated characteristics and target rod performance. Many of the target rod components: cladding tubes, end caps, plenum springs, etc., have similar counterparts in LWR fuel rods. High production rate manufacture and inspection of these components has beenmore » adequately demonstrated by nuclear fuel rod manufacturers. This summary describes the more non-conventional manufacturing processes and inspection techniques developed to fabricate target rod components whose manufacturability at required production rates had not been previously demonstrated.« less

  3. Chromosome aberrations in workers occupationally exposed to tritium.

    PubMed

    Tawn, E Janet; Curwen, Gillian B; Riddell, Anthony E

    2018-06-01

    This paper reports the findings of an historical chromosome analysis for unstable aberrations, undertaken on 34 nuclear workers with monitored exposure to tritium. The mean recorded β-particle dose from tritium was 9.33 mGy (range 0.25-79.71 mGy) and the mean occupational dose from external, mainly γ-ray, irradiation was 1.94 mGy (range 0.00-7.71 mGy). The dicentric frequency of 1.91 ± 0.53 × 10 -3 per cell was significantly raised, in comparison with that of 0.61 ± 0.30 × 10 -3 per cell for a group of 66 comparable worker controls unexposed to occupational radiation. The frequency of total aberrations was also significantly higher in the tritium workers. Comparisons with in vitro studies indicate that at these dose levels an increase in aberration frequency is not expected. However, the available historical tritium dose records were produced for the purposes of radiological protection and based on a methodology that has since been updated, so tritium doses are subject to considerable uncertainty. It is therefore recommended that, if possible, tritium doses are reassessed using information on historical recording practices in combination with current dosimetry methodology, and that further chromosome studies are undertaken using modern FISH techniques to establish stable aberration frequencies, as these will provide information on a cumulative biological effect.

  4. Estimation of Biological Effects of Tritium.

    PubMed

    Umata, Toshiyuki

    2017-01-01

    Nuclear fusion technology is expected to create new energy in the future. However, nuclear fusion requires a large amount of tritium as a fuel, leading to concern about the exposure of radiation workers to tritium beta radiation. Furthermore, countermeasures for tritium-polluted water produced in decommissioning of the reactor at Fukushima Daiichi Nuclear Power Station may potentially cause health problems in radiation workers. Although, internal exposure to tritium at a low dose/low dose rate can be assumed, biological effect of tritium exposure is not negligible, because tritiated water (HTO) intake to the body via the mouth/inhalation/skin would lead to homogeneous distribution throughout the whole body. Furthermore, organically-bound tritium (OBT) stays in the body as parts of the molecules that comprise living organisms resulting in long-term exposure, and the chemical form of tritium should be considered. To evaluate the biological effect of tritium, the effect should be compared with that of other radiation types. Many studies have examined the relative biological effectiveness (RBE) of tritium. Hence, we report the RBE, which was obtained with radiation carcinogenesis classified as a stochastic effect, and serves as a reference for cancer risk. We also introduce the outline of the tritium experiment and the principle of a recently developed animal experimental system using transgenic mouse to detect the biological influence of radiation exposure at a low dose/low dose rate.

  5. Drum bubbler tritium processing system

    DOEpatents

    Rule, Keith; Gettelfinger, Geoff; Kivler, Paul

    1999-01-01

    A method of separating tritium oxide from a gas stream containing tritium oxide. The gas stream containing tritium oxide is fed into a container of water having a head space above the water. Bubbling the gas stream containing tritium oxide through the container of water and removing gas from the container head space above the water. Thereafter, the gas from the head space is dried to remove water vapor from the gas, and the water vapor is recycled to the container of water.

  6. SHINE Tritium Nozzle Design: Activity 6, Task 1 Report

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

    Okhuysen, Brett S.; Pulliam, Elias Noel

    In FY14, we studied the qualitative and quantitative behavior of a SHINE/PNL tritium nozzle under varying operating conditions. The result is an understanding of the nozzle’s performance in terms of important flow features that manifest themselves under different parametric profiles. In FY15, we will consider nozzle design with a focus on nozzle geometry and integration. From FY14 work, we will understand how the SHINE/PNL nozzle behaves under different operating scenarios. The first task for FY15 is to evaluate the FY14 model as a predictor of the actual flow. Considering different geometries is more time-intensive than parameter studies, therefore we recommendmore » considering any relevant flow features that were not included in the FY14 model. In the absence of experimental data, it is particularly important to consider any sources of heat in the domain or boundary conditions that may affect the flow and incorporate these into the simulation if they are significant. Additionally, any geometric features of the beamline segment should be added to the model such as the orifice plate. The FY14 model works with hydrogen. An improvement that can be made for FY15 is to develop CFD properties for tritium and incorporate those properties into the new models.« less

  7. Tritium monitor with improved gamma-ray discrimination

    DOEpatents

    Cox, Samson A.; Bennett, Edgar F.; Yule, Thomas J.

    1985-01-01

    Apparatus and method for selective measurement of tritium oxide in an environment which may include other radioactive components and gamma radiation, the measurement including the selective separation of tritium oxide from a sample gas through a membrane into a counting gas, the generation of electrical pulses individually representative by rise times of tritium oxide and other radioactivity in the counting gas, separation of the pulses by rise times, and counting of those pulses representative of tritium oxide. The invention further includes the separate measurement of any tritium in the sample gas by oxidizing the tritium to tritium oxide and carrying out a second separation and analysis procedure as described above.

  8. Tritium monitor with improved gamma-ray discrimination

    DOEpatents

    Cox, S.A.; Bennett, E.F.; Yule, T.J.

    1982-10-21

    Apparatus and method are presented for selective measurement of tritium oxide in an environment which may include other radioactive components and gamma radiation, the measurement including the selective separation of tritium oxide from a sample gas through a membrane into a counting gas, the generation of electrical pulses individually representative by rise times of tritium oxide and other radioactivity in the counting gas, separation of the pulses by rise times, and counting of those pulses representative of tritium oxide. The invention further includes the separate measurement of any tritium in the sample gas by oxidizing the tritium to tritium oxide and carrying out a second separation and analysis procedure as described above.

  9. TRITIUM EFFECTS ON WELDMENT FRACTURE TOUGHNESS

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

    Morgan, M; Michael Tosten, M; Scott West, S

    2006-07-17

    The effects of tritium on the fracture toughness properties of Type 304L stainless steel and its weldments were measured. Fracture toughness data are needed for assessing tritium reservoir structural integrity. This report provides data from J-Integral fracture toughness tests on unexposed and tritium-exposed weldments. The effect of tritium on weldment toughness has not been measured until now. The data include tests on tritium-exposed weldments after aging for up to three years to measure the effect of increasing decay helium concentration on toughness. The results indicate that Type 304L stainless steel weldments have high fracture toughness and are resistant to tritiummore » aging effects on toughness. For unexposed alloys, weldment fracture toughness was higher than base metal toughness. Tritium-exposed-and-aged base metals and weldments had lower toughness values than unexposed ones but still retained good toughness properties. In both base metals and weldments there was an initial reduction in fracture toughness after tritium exposure but little change in fracture toughness values with increasing helium content in the range tested. Fracture modes occurred by the dimpled rupture process in unexposed and tritium-exposed steels and welds. This corroborates further the resistance of Type 304L steel to tritium embrittlement. This report fulfills the requirements for the FY06 Level 3 milestone, TSR15.3 ''Issue summary report for tritium reservoir material aging studies'' for the Enhanced Surveillance Campaign (ESC). The milestone was in support of ESC L2-1866 Milestone-''Complete an annual Enhanced Surveillance stockpile aging assessment report to support the annual assessment process''.« less

  10. Tritium migration from a low-level radioactive-waste disposal site near Chicago, Illinois

    USGS Publications Warehouse

    Nicholas, J.R.; Healy, R.W.

    1988-01-01

    This paper describes the results of a study to determine the geologic and hydrologic factors that control migration of tritium from a closed, low-level radioactive-waste disposal site. The disposal site, which operated from 1943 to mid1949, contains waste generated by research activities at the world's first nuclear reactors. Tritium has migrated horizontally at least 1,300 feet northward in glacial drift and more than 650 feet in the underlying dolomite. Thin, gently sloping sand layers in an otherwise clayey glacial drift are major conduits for ground-water flow and tritium migration in a perched zone beneath the disposal site. Tritium concentrations in the drift beneath the disposal site exceed 100,000 nanocuries per liter. Regional horizontal joints in the dolomite are enlarged by solution and are the major conduits for ground-water flow and tritium migration in the dolomite. A weathered zone at the top of the dolomite also is a pathway for tritium migration. The maximum measured tritium concentration in the dolomite is 29.4 nanocuries per liter. Fluctuations of tritium concentration in the dolomite are the result of dilution by seasonal recharge from the drift.

  11. Tritium environmental transport studies at TFTR

    NASA Astrophysics Data System (ADS)

    Ritter, P. D.; Dolan, T. J.; Longhurst, G. R.

    1993-06-01

    Environmental tritium concentrations will be measured near the Tokamak Fusion Test Reactor (TFTR) to help validate dynamic models of tritium transport in the environment. For model validation the database must contain sequential measurements of tritium concentrations in key environmental compartments. Since complete containment of tritium is an operational goal, the supplementary monitoring program should be able to glean useful data from an unscheduled acute release. Portable air samplers will be used to take samples automatically every 4 hours for a week after an acute release, thus obtaining the time resolution needed for code validation. Samples of soil, vegetation, and foodstuffs will be gathered daily at the same locations as the active air monitors. The database may help validate the plant/soil/air part of tritium transport models and enhance environmental tritium transport understanding for the International Thermonuclear Experimental Reactor (ITER).

  12. Regeneration and tritium recovery from the large JET neutral injection cryopump system after the FTE. [First Tritium Experiment (FTE)

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

    Obert, W.; Bell, A.; Davies, J.

    1992-01-01

    Neutral Beam Injection (NBI) was used to introduce tritium into the plasma for the First Tritium Experiment In addition to the decisive advantage of depositing the tritium into the centre of the plasma, the use of NBI also minimized the total quantity of tritium introduced into the Torus and the contamination of the vacuum vessel. However, because of the relatively low gas efficiency of the positive ion injection system approximately 95% of the total quantity of tritium introduced was pumped by the large condensation cryopumps which form an integral part of the injector. Several hardware and associated software changes weremore » implemented in order to making provision for possible fault scenarios during operation with tritium and to ensure complete regeneration of the tritium from the cryopumps. The tritium released after all subsequent regeneration's has been monitored carefully in order to determine the amount of tritium retained by the black anodized liquid nitrogen panel surfaces of the cryopump and to compare it with experiments at TSTA on JET samples before the FTE.« less

  13. Composition containing aerogel substrate loaded with tritium

    DOEpatents

    Ashley, Carol S.; Brinker, C. Jeffrey; Ellefson, Robert E.; Gill, John T.; Reed, Scott; Walko, Robert J.

    1992-01-01

    The invention provides a process for loading an aerogel substrate with tritium and the resultant compositions. According to the process, an aerogel substrate is hydrolyzed so that surface OH groups are formed. The hydrolyzed aerogel is then subjected to tritium exchange employing, for example, a tritium-containing gas, whereby tritium atoms replace H atoms of surface OH groups. OH and/or CH groups of residual alcohol present in the aerogel may also undergo tritium exchange.

  14. Effect of the self-pumped limiter concept on the tritium fuel cycle

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

    Finn, P.A.; Sze, D.K.; Hassanein, A.

    1988-09-01

    The self-pumped limiter concept was the impurity control system for the reactor in the Tokamak Power Systems Study (TPSS). The use of a self-pumped limiter had a major impact on the design of the tritium systems of the TPSS fusion reactor. The self-pumped limiter functions by depositing the helium ash under a layer of metal (vanadium). The majority of the hydrogen species are recycled at the plasma edge; a small fraction permeates to the blanket/coolant which was lithium in TPSS. Use of the self-pumped limiter results in the elimination of the plasma processing system. Thus, the blanket tritium processing systemmore » becomes the major tritium system. The main advantages achieved for the tritium systems with a self-pumped limiter are a reduction in the capital cost of tritium processing equipment as well as a reduction in building space, a reduced tritium inventory for processing and for reserve storage, an increase in the inherent safety of the fusion plant and an improvement in economics for a fusion world economy.« less

  15. Improving tritium exposure reconstructions using accelerator mass spectrometry

    PubMed Central

    Hunt, J. R.; Vogel, J. S.; Knezovich, J. P.

    2010-01-01

    Direct measurement of tritium atoms by accelerator mass spectrometry (AMS) enables rapid low-activity tritium measurements from milligram-sized samples and permits greater ease of sample collection, faster throughput, and increased spatial and/or temporal resolution. Because existing methodologies for quantifying tritium have some significant limitations, the development of tritium AMS has allowed improvements in reconstructing tritium exposure concentrations from environmental measurements and provides an important additional tool in assessing the temporal and spatial distribution of chronic exposure. Tritium exposure reconstructions using AMS were previously demonstrated for a tree growing on known levels of tritiated water and for trees exposed to atmospheric releases of tritiated water vapor. In these analyses, tritium levels were measured from milligram-sized samples with sample preparation times of a few days. Hundreds of samples were analyzed within a few months of sample collection and resulted in the reconstruction of spatial and temporal exposure from tritium releases. Although the current quantification limit of tritium AMS is not adequate to determine natural environmental variations in tritium concentrations, it is expected to be sufficient for studies assessing possible health effects from chronic environmental tritium exposure. PMID:14735274

  16. Methods for tritium labeling

    DOEpatents

    Andres, Hendrik; Morimoto, Hiromi; Williams, Philip G.

    1993-01-01

    Reagents and processes for reductively introducing deuterium or tritium into organic molecules are described. The reagents are deuterium or tritium analogs of trialkyl boranes, borane or alkali metal aluminum hydrides. The process involves forming these reagents in situ from alkali metal tritides or deuterides.

  17. Estimating cancer risk in relation to tritium exposure from routine operation of a nuclear-generating station in Pickering, Ontario.

    PubMed

    Wanigaratne, S; Holowaty, E; Jiang, H; Norwood, T A; Pietrusiak, M A; Brown, P

    2013-09-01

    Evidence suggests that current levels of tritium emissions from CANDU reactors in Canada are not related to adverse health effects. However, these studies lack tritium-specific dose data and have small numbers of cases. The purpose of our study was to determine whether tritium emitted from a nuclear-generating station during routine operation is associated with risk of cancer in Pickering, Ontario. A retrospective cohort was formed through linkage of Pickering and north Oshawa residents (1985) to incident cancer cases (1985-2005). We examined all sites combined, leukemia, lung, thyroid and childhood cancers (6-19 years) for males and females as well as female breast cancer. Tritium estimates were based on an atmospheric dispersion model, incorporating characteristics of annual tritium emissions and meteorology. Tritium concentration estimates were assigned to each cohort member based on exact location of residence. Person-years analysis was used to determine whether observed cancer cases were higher than expected. Cox proportional hazards regression was used to determine whether tritium was associated with radiation-sensitive cancers in Pickering. Person-years analysis showed female childhood cancer cases to be significantly higher than expected (standardized incidence ratio [SIR] = 1.99, 95% confidence interval [CI]: 1.08-3.38). The issue of multiple comparisons is the most likely explanation for this finding. Cox models revealed that female lung cancer was significantly higher in Pickering versus north Oshawa (HR = 2.34, 95% CI: 1.23-4.46) and that tritium was not associated with increased risk. The improved methodology used in this study adds to our understanding of cancer risks associated with low-dose tritium exposure. Tritium estimates were not associated with increased risk of radiationsensitive cancers in Pickering.

  18. In-vessel tritium retention and removal in ITER

    NASA Astrophysics Data System (ADS)

    Federici, G.; Anderl, R. A.; Andrew, P.; Brooks, J. N.; Causey, R. A.; Coad, J. P.; Cowgill, D.; Doerner, R. P.; Haasz, A. A.; Janeschitz, G.; Jacob, W.; Longhurst, G. R.; Nygren, R.; Peacock, A.; Pick, M. A.; Philipps, V.; Roth, J.; Skinner, C. H.; Wampler, W. R.

    Tritium retention inside the vacuum vessel has emerged as a potentially serious constraint in the operation of the International Thermonuclear Experimental Reactor (ITER). In this paper we review recent tokamak and laboratory data on hydrogen, deuterium and tritium retention for materials and conditions which are of direct relevance to the design of ITER. These data, together with significant advances in understanding the underlying physics, provide the basis for modelling predictions of the tritium inventory in ITER. We present the derivation, and discuss the results, of current predictions both in terms of implantation and codeposition rates, and critically discuss their uncertainties and sensitivity to important design and operation parameters such as the plasma edge conditions, the surface temperature, the presence of mixed-materials, etc. These analyses are consistent with recent tokamak findings and show that codeposition of tritium occurs on the divertor surfaces primarily with carbon eroded from a limited area of the divertor near the strike zones. This issue remains an area of serious concern for ITER. The calculated codeposition rates for ITER are relatively high and the in-vessel tritium inventory limit could be reached, under worst assumptions, in approximately a week of continuous operation. We discuss the implications of these estimates on the design, operation and safety of ITER and present a strategy for resolving the issues. We conclude that as long as carbon is used in ITER - and more generically in any other next-step experimental fusion facility fuelled with tritium - the efficient control and removal of the codeposited tritium is essential. There is a critical need to develop and test in situ cleaning techniques and procedures that are beyond the current experience of present-day tokamaks. We review some of the principal methods that are being investigated and tested, in conjunction with the R&D work still required to extrapolate their

  19. PRODUCTION OF TRITIUM

    DOEpatents

    Jenks, G.H.; Shapiro, E.M.; Elliott, N.; Cannon, C.V.

    1963-02-26

    This invention relates to a process for the production of tritium by subjecting comminuted solid lithium fluoride containing the lithium isotope of atomic mass number 6 to neutron radiation in a self-sustaining neutronic reactor. The lithium fiuoride is heated to above 450 deg C. in an evacuated vacuum-tight container during radiation. Gaseous radiation products are withdrawn and passed through a palladium barrier to recover tritium. (AEC)

  20. Tritium Decay Helium-3 Effects in Tungsten

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

    Shimada, M.; Merrill, B. J.

    2016-06-01

    A critical challenge for long-term operation of ITER and beyond to a Demonstration reactor (DEMO) and future fusion reactor will be the development of plasma-facing components (PFCs) that demonstrate erosion resistance to steady-state/transient heat fluxes and intense neutral/ion particle fluxes under the extreme fusion nuclear environment, while at the same time minimizing in-vessel tritium inventories and permeation fluxes into the PFC’s coolant. Tritium will diffuse in bulk tungsten at elevated temperatures, and can be trapped in radiation-induced trap site (up to 1 at. % T/W) in tungsten [1,2]. Tritium decay into helium-3 may also play a major role in microstructuralmore » evolution (e.g. helium embrittlement) in tungsten due to relatively low helium-4 production (e.g. He/dpa ratio of 0.4-0.7 appm [3]) in tungsten. Tritium-decay helium-3 effect on tungsten is hardly understood, and its database is very limited. Two tungsten samples (99.99 at. % purity from A.L.M.T. Co., Japan) were exposed to high flux (ion flux of 1.0x1022 m-2s-1 and ion fluence of 1.0x1026 m-2) 0.5%T2/D2 plasma at two different temperatures (200, and 500°C) in Tritium Plasma Experiment (TPE) at Idaho National Laboratory. Tritium implanted samples were stored at ambient temperature in air for more than 3 years to investigate tritium decay helium-3 effect in tungsten. The tritium distributions on plasma-exposed was monitored by a tritium imaging plate technique during storage period [4]. Thermal desorption spectroscopy was performed with a ramp rate of 10°C/min up to 900°C to outgas residual deuterium and tritium but keep helium-3 in tungsten. These helium-3 implanted samples were exposed to deuterium plasma in TPE to investigate helium-3 effect on deuterium behavior in tungsten. The results show that tritium surface concentration in 200°C sample decreased to 30 %, but tritium surface concentration in 500°C sample did not alter over the 3 years storage period, indicating possible

  1. Organically bound tritium (OBT) for various plants in the vicinity of a continuous atmospheric tritium release.

    PubMed

    Vichot, L; Boyer, C; Boissieux, T; Losset, Y; Pierrat, D

    2008-10-01

    In order to quantify tritium impact on the environmental, we studied vegetation continuously exposed to a tritiated atmosphere. We chose lichens as bio-indicators, trees for determination of past tritium releases of the Valduc Centre, and lettuce as edible vegetables for dose calculation regarding neighbourhood. The Pasquill and Doury models from the literature were tested to estimate tritium concentration in the air around vegetable for distance from the release point less than 500 m. The results in tree rings show that organically bound tritium (OBT) concentration was strongly correlated with tritium releases. Using the GASCON model, the modelled variation of OBT concentration with distance was correlated with the measurements. Although lichens are recognized as bio-indicators, our experiments show that they were not convenient for environmental surveys because their age is not definitive. Thus, tritium integration time cannot be precisely determined. Furthermore, their biological metabolism is not well known and tritium concentration appears to be largely dependent on species. An average conversion rate of HTO to OBT was determined for lettuce of about 0.20-0.24% h(-1). Nevertheless, even if it is equivalent to values already published in the literature for other vegetation, we have shown that this conversion rate, established by weekly samples, varies by a factor of 10 during the different stages of lettuce development, and that its variation is linked to the biomass derivative.

  2. Tritium Management Loop Design Status

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

    Rader, Jordan D.; Felde, David K.; McFarlane, Joanna

    This report summarizes physical, chemical, and engineering analyses that have been done to support the development of a test loop to study tritium migration in 2LiF-BeF2 salts. The loop will operate under turbulent flow and a schematic of the apparatus has been used to develop a model in Mathcad to suggest flow parameters that should be targeted in loop operation. The introduction of tritium into the loop has been discussed as well as various means to capture or divert the tritium from egress through a test assembly. Permeation was calculated starting with a Modelica model for a transport through amore » nickel window into a vacuum, and modifying it for a FLiBe system with an argon sweep gas on the downstream side of the permeation interface. Results suggest that tritium removal with a simple tubular permeation device will occur readily. Although this system is idealized, it suggests that rapid measurement capability in the loop may be necessary to study and understand tritium removal from the system.« less

  3. Fermilab | Tritium at Fermilab | Ferry Creek Results

    Science.gov Websites

    newsletter Ferry Creek Results chart This chart (click chart for larger version) shows the levels of tritium following the detection of low levels of tritium in Indian Creek in November 2005. The levels of tritium in . Fermilab continues to monitor the ponds and creeks on its site and take steps to keep the levels of tritium

  4. Studies on the behaviour of tritium in components and structure materials of tritium confinement and detritiation systems of ITER

    NASA Astrophysics Data System (ADS)

    Kobayashi, K.; Isobe, K.; Iwai, Y.; Hayashi, T.; Shu, W.; Nakamura, H.; Kawamura, Y.; Yamada, M.; Suzuki, T.; Miura, H.; Uzawa, M.; Nishikawa, M.; Yamanishi, T.

    2007-12-01

    Confinement and the removal of tritium are key subjects for the safety of ITER. The ITER buildings are confinement barriers of tritium. In a hot cell, tritium is often released as vapour and is in contact with the inner walls. The inner walls of the ITER tritium plant building will also be exposed to tritium in an accident. The tritium released in the buildings is removed by the atmosphere detritiation systems (ADS), where the tritium is oxidized by catalysts and is removed as water. A special gas of SF6 is used in ITER and is expected to be released in an accident such as a fire. Although the SF6 gas has potential as a catalyst poison, the performance of ADS with the existence of SF6 has not been confirmed as yet. Tritiated water is produced in the regeneration process of ADS and is subsequently processed by the ITER water detritiation system (WDS). One of the key components of the WDS is an electrolysis cell. To overcome the issues in a global tritium confinement, a series of experimental studies have been carried out as an ITER R&D task: (1) tritium behaviour in concrete; (2) the effect of SF6 on the performance of ADS and (3) tritium durability of the electrolysis cell of the ITER-WDS. (1) The tritiated water vapour penetrated up to 50 mm into the concrete from the surface in six months' exposure. The penetration rate of tritium in the concrete was thus appreciably first, the isotope exchange capacity of the cement paste plays an important role in tritium trapping and penetration into concrete materials when concrete is exposed to tritiated water vapour. It is required to evaluate the effect of coating on the penetration rate quantitatively from the actual tritium tests. (2) SF6 gas decreased the detritiation factor of ADS. Since the effect of SF6 depends closely on its concentration, the amount of SF6 released into the tritium handling area in an accident should be reduced by some ideas of arrangement of components in the buildings. (3) It was expected that

  5. Tritium handling experience at Atomic Energy of Canada Limited

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

    Suppiah, S.; McCrimmon, K.; Lalonde, S.

    2015-03-15

    Canada has been a leader in tritium handling technologies as a result of the successful CANDU reactor technology used for power production. Over the last 50 to 60 years, capabilities have been established in tritium handling and tritium management in CANDU stations, tritium removal processes for heavy and light water, tritium measurement and monitoring, and understanding the effects of tritium on the environment. This paper outlines details of tritium-related work currently being carried out at Atomic Energy of Canada Limited (AECL). It concerns the CECE (Combined Electrolysis and Catalytic Exchange) process for detritiation, tritium-compatible electrolysers, tritium permeation studies, and tritiummore » powered batteries. It is worth noting that AECL offers a Tritium Safe-Handling Course to national and international participants, the course is a mixture of classroom sessions and hands-on practical exercises. The expertise and facilities available at AECL is ready to address technological needs of nuclear fusion and next-generation nuclear fission reactors related to tritium handling and related issues.« less

  6. A low tritium hydride bed inventory estimation technique

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

    Klein, J.E.; Shanahan, K.L.; Baker, R.A.

    2015-03-15

    Low tritium hydride beds were developed and deployed into tritium service in Savannah River Site. Process beds to be used for low concentration tritium gas were not fitted with instrumentation to perform the steady-state, flowing gas calorimetric inventory measurement method. Low tritium beds contain less than the detection limit of the IBA (In-Bed Accountability) technique used for tritium inventory. This paper describes two techniques for estimating tritium content and uncertainty for low tritium content beds to be used in the facility's physical inventory (PI). PI are performed periodically to assess the quantity of nuclear material used in a facility. Themore » first approach (Mid-point approximation method - MPA) assumes the bed is half-full and uses a gas composition measurement to estimate the tritium inventory and uncertainty. The second approach utilizes the bed's hydride material pressure-composition-temperature (PCT) properties and a gas composition measurement to reduce the uncertainty in the calculated bed inventory.« less

  7. DEPLOYMENT OF THE BULK TRITIUM SHIPPING PACKAGE

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

    Blanton, P.

    A new Bulk Tritium Shipping Package (BTSP) was designed by the Savannah River National Laboratory to be a replacement for a package that has been used to ship tritium in a variety of content configurations and forms since the early 1970s. The BTSP was certified by the National Nuclear Safety Administration in 2011 for shipments of up to 150 grams of Tritium. Thirty packages were procured and are being delivered to various DOE sites for operational use. This paper summarizes the design features of the BTSP, as well as associated engineered material improvements. Fabrication challenges encountered during production are discussedmore » as well as fielding requirements. Current approved tritium content forms (gas and tritium hydrides), are reviewed, as well as, a new content, tritium contaminated water on molecular sieves. Issues associated with gas generation will also be discussed.« less

  8. Verification of Modelica-Based Models with Analytical Solutions for Tritium Diffusion

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

    Rader, Jordan D.; Greenwood, Michael Scott; Humrickhouse, Paul W.

    Here, tritium transport in metal and molten salt fluids combined with diffusion through high-temperature structural materials is an important phenomenon in both magnetic confinement fusion (MCF) and molten salt reactor (MSR) applications. For MCF, tritium is desirable to capture for fusion fuel. For MSRs, uncaptured tritium potentially can be released to the environment. In either application, quantifying the time- and space-dependent tritium concentration in the working fluid(s) and structural components is necessary.Whereas capability exists specifically for calculating tritium transport in such systems (e.g., using TMAP for fusion reactors), it is desirable to unify the calculation of tritium transport with othermore » system variables such as dynamic fluid and structure temperature combined with control systems such as those that might be found in a system code. Some capability for radioactive trace substance transport exists in thermal-hydraulic systems codes (e.g., RELAP5-3D); however, this capability is not coupled to species diffusion through solids. Combined calculations of tritium transport and thermal-hydraulic solution have been demonstrated with TRIDENT but only for a specific type of MSR.Researchers at Oak Ridge National Laboratory have developed a set of Modelica-based dynamic system modeling tools called TRANsient Simulation Framework Of Reconfigurable Models (TRANSFORM) that were used previously to model advanced fission reactors and associated systems. In this system, the augmented TRANSFORM library includes dynamically coupled fluid and solid trace substance transport and diffusion. Results from simulations are compared against analytical solutions for verification.« less

  9. Verification of Modelica-Based Models with Analytical Solutions for Tritium Diffusion

    DOE PAGES

    Rader, Jordan D.; Greenwood, Michael Scott; Humrickhouse, Paul W.

    2018-03-20

    Here, tritium transport in metal and molten salt fluids combined with diffusion through high-temperature structural materials is an important phenomenon in both magnetic confinement fusion (MCF) and molten salt reactor (MSR) applications. For MCF, tritium is desirable to capture for fusion fuel. For MSRs, uncaptured tritium potentially can be released to the environment. In either application, quantifying the time- and space-dependent tritium concentration in the working fluid(s) and structural components is necessary.Whereas capability exists specifically for calculating tritium transport in such systems (e.g., using TMAP for fusion reactors), it is desirable to unify the calculation of tritium transport with othermore » system variables such as dynamic fluid and structure temperature combined with control systems such as those that might be found in a system code. Some capability for radioactive trace substance transport exists in thermal-hydraulic systems codes (e.g., RELAP5-3D); however, this capability is not coupled to species diffusion through solids. Combined calculations of tritium transport and thermal-hydraulic solution have been demonstrated with TRIDENT but only for a specific type of MSR.Researchers at Oak Ridge National Laboratory have developed a set of Modelica-based dynamic system modeling tools called TRANsient Simulation Framework Of Reconfigurable Models (TRANSFORM) that were used previously to model advanced fission reactors and associated systems. In this system, the augmented TRANSFORM library includes dynamically coupled fluid and solid trace substance transport and diffusion. Results from simulations are compared against analytical solutions for verification.« less

  10. Tritium systems test assembly stabilization

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

    Jasen, W. G.; Michelotti, R. A.; Anast, K. R.

    The Tritium Systems Test Assembly (TSTA) was a facility dedicated to tritium technology Research and Development (R&D) primarily for future fusion power reactors. The facility was conceived in mid 1970's, operations commenced in early 1980's, stabilization and deactivation began in 2000 and were completed in 2003. The facility will remain in a Surveillance and Maintenance (S&M) mode until the Department of Energy (DOE) funds demolition of the facility, tentatively in 2009. A safe and stable end state was achieved by the TSTA Facility Stabilization Project (TFSP) in anticipation of long term S&M. At the start of the stabilization project, withmore » an inventory of approximately 140 grams of tritium, the facility was designated a Hazard Category (HC) 2 Non-Reactor Nuclear facility as defined by US Department of Energy standard DOE-STD-1027-92 (1997). The TSTA facility comprises a laboratory area, supporting rooms, offices and associated laboratory space that included more than 20 major tritium handling systems. The project's focus was to reduce the tritium inventory by removing bulk tritium, tritiated water wastes, and tritium-contaminated high-inventory components. Any equipment that remained in the facility was stabilized in place. All of the gloveboxes and piping were rendered inoperative and vented to atmosphere. All equipment, and inventoried tritium contamination, remaining in the facility was left in a safe-and-stable state. The project used the End Points process as defined by the DOE Office of Environmental Management (web page http://www.em.doe.- gov/deact/epman.htmtlo) document and define the end state required for the stabilization of TSTA Facility. The End Points process added structure that was beneficial through virtually all phases of the project. At completion of the facility stabilization project the residual tritium inventory was approximately 3,000 curies, considerably less than the 1.6-gram threshold for a HC 3 facility. TSTA is now designated

  11. Fermilab | Tritium at Fermilab | Frequently asked questions

    Science.gov Websites

    computing Quantum initiatives Research and development Key discoveries Benefits of particle physics Particle Accelerators Leading accelerator technology Accelerator complex Illinois Accelerator Research Center Fermilab questions about tritium Tritium in surface water Indian Creek Kress Creek Ferry Creek Tritium in sanitary

  12. Tritium program at Chalk River Laboratories

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

    Brown, R.M.; Workman, W.J.; Kotzer, T.G.

    1993-01-01

    Control of tritium dispersal within and around the research and power stations of the Canadian nuclear program has always been recognized as particularly important because of the high production of tritium in heavy-water-moderated reactors. At the Chalk River Labs, (CRL), two major research reactors have operated for more than 30 yr. Over the years, emissions have been from 300 to 700 TBq/yr (8 to 19 kCi/yr) to the atmosphere and from 100 to 200 TBq/yr (3 to 5 kCi/yr) to local water systems. This results in concentrations in atmospheric moisture of [approximately]600 Bq/[ell] water in the immediate reactor area, 80more » Bq/[ell] at the exclusion area boundary (7 km distant), and 50 Bq/[ell] at the nearest downwind community (12 km).« less

  13. PDRD (SR13046) TRITIUM PRODUCTION FINAL REPORT

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

    Smith, P.; Sheetz, S.

    Utilizing the results of Texas A&M University (TAMU) senior design projects on tritium production in four different small modular reactors (SMR), the Savannah River National Laboratory’s (SRNL) developed an optimization model evaluating tritium production versus uranium utilization under a FY2013 plant directed research development (PDRD) project. The model is a tool that can evaluate varying scenarios and various reactor designs to maximize the production of tritium per unit of unobligated United States (US) origin uranium that is in limited supply. The primary module in the model compares the consumption of uranium for various production reactors against the base case ofmore » Watts Bar I running a nominal load of 1,696 tritium producing burnable absorber rods (TPBARs) with an average refueling of 41,000 kg low enriched uranium (LEU) on an 18 month cycle. After inputting an initial year, starting inventory of unobligated uranium and tritium production forecast, the model will compare and contrast the depletion rate of the LEU between the entered alternatives. This is an annual tritium production rate of approximately 0.059 grams of tritium per kilogram of LEU (g-T/kg-LEU). To date, the Nuclear Regulatory Commission (NRC) license has not been amended to accept a full load of TPBARs so the nominal tritium production has not yet been achieved. The alternatives currently loaded into the model include the three light water SMRs evaluated in TAMU senior projects including, mPower, Holtec and NuScale designs. Initial evaluations of tritium production in light water reactor (LWR) based SMRs using optimized loads TPBARs is on the order 0.02-0.06 grams of tritium per kilogram of LEU used. The TAMU students also chose to model tritium production in the GE-Hitachi SPRISM, a pooltype sodium fast reactor (SFR) utilizing a modified TPBAR type target. The team was unable to complete their project so no data is available. In order to include results from a fast reactor, the

  14. Thin film tritium dosimetry

    DOEpatents

    Moran, Paul R.

    1976-01-01

    The present invention provides a method for tritium dosimetry. A dosimeter comprising a thin film of a material having relatively sensitive RITAC-RITAP dosimetry properties is exposed to radiation from tritium, and after the dosimeter has been removed from the source of the radiation, the low energy electron dose deposited in the thin film is determined by radiation-induced, thermally-activated polarization dosimetry techniques.

  15. Recovery of tritium from tritiated molecules

    DOEpatents

    Swansiger, W.A.

    1984-10-17

    This invention relates to the recovery of tritium from various tritiated molecules by reaction with uranium. More particularly, the invention relates to the recovery of tritium from tritiated molecules by reaction with uranium wherein the reaction is conducted in a reactor which permits the reaction to occur as a moving front reaction from the point where the tritium enters the reactor charged with uranium down the reactor until the uranium is exhausted.

  16. Report of the Defense Science Board task force on tritium production technology options. Final technical report

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

    Welch, L.

    1999-05-01

    The long-standing national security policy of the US to maintain a robust nuclear deterrent continues to be supported by the Congress and the President. The President has stated that ``...the nuclear deterrent posture is one of the most visible and important examples of how US military capabilities can be used effectively to deter aggression and coercion. Nuclear weapons serve as a hedge against an uncertain future, a guarantee of our security commitments to allies, and a disincentive to those who would contemplate developing or otherwise acquiring their own nuclear weapons.`` US nuclear weapons designs require tritium, an isotope of hydrogen,more » which has not been produced in the US since 1988, when the last tritium production facility (the K-Reactor at the Savannah River Site) was shut down. This long period without tritium production in the US has been possible because arms control agreements reached in the early 1990s reduced the size of the US nuclear weapons stockpile and because the Department of Energy (DOE) met stockpile tritium requirements by recycling the tritium removed from dismantled nuclear weapons. However, since tritium decays at a rate of 5.5% each year, a dependable source of tritium is required to continue to sustain the US nuclear weapons stockpile to underwrite national security policy and to support arms control goals. The US does maintain a five-year reserve supply of tritium, but this reserve is to be used only in an emergency. Current guidance states the reserve must be restored to its original level within five years of being used. To sustain the START I level, tritium production needs to begin around 2005 at a production capacity of about 3.0 kg/ year. START II levels could be sustained with production of about 1.5 kg/year beginning around 2011.« less

  17. Future use of tritium in mapping pre-bomb groundwater volumes.

    PubMed

    Eastoe, C J; Watts, C J; Ploughe, M; Wright, W E

    2012-01-01

    The tritium input to groundwater, represented as volume-weighted mean tritium concentrations in precipitation, has been close to constant in Tucson and Albuquerque since 1992, and the decrease in tritium concentrations at the tail end of the bomb tritium pulse has ceased. To determine the future usefulness of tritium measurements in southwestern North America, volume-weighted mean tritium levels in seasonal aggregate precipitation samples have been gathered from 26 sites. The averages range from 2 to 9 tritium units (TU). Tritium concentrations increase with site latitude, and possibly with distance from the coast and with site altitude, reflecting local ratios of combination of low-tritium moisture advected from the oceans with high-tritium moisture originating near the tropopause. Tritium used alone as a tool for mapping aquifer volumes containing only pre-bomb recharge to groundwater will become ambiguous when the tritium in precipitation at the end of the bomb tritium pulse decays to levels close to the analytical detection limit. At such a time, tritium in precipitation from the last one to two decades of the bomb pulse will become indistinguishable from pre-bomb recharge. The threshold of ambiguity has already arrived in coastal areas with a mean of 2 TU in precipitation and will follow in the next three decades throughout the study region. Where the mean tritium level is near 5 TU, the threshold will occur between 2025 and 2030, given a detection limit of 0.6 TU. Similar thresholds of ambiguity, with different local timing possible, apply globally. © 2011, The Author(s). Ground Water © 2011, National Ground Water Association.

  18. EFFECTS OF TRITIUM GAS EXPOSURE ON EPDM ELASTOMER

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

    Clark, E.

    2009-12-11

    Samples of four formulations of ethylene-propylene diene monomer (EPDM) elastomer were exposed to initially pure tritium gas at one atmosphere and ambient temperature for various times up to about 420 days in closed containers. Two formulations were carbon-black-filled commercial formulations, and two were the equivalent formulations without filler synthesized for this work. Tritium effects on the samples were characterized by measuring the sample volume, mass, flexibility, and dynamic mechanical properties and by noting changes in appearance. The glass transition temperature was determined by analysis of the dynamic mechanical properties. The glass transition temperature increased significantly with tritium exposure, and themore » unfilled formulations ceased to behave as elastomers after the longest tritium exposure. The filled formulations were more resistant to tritium exposure. Tritium exposure made all samples significantly stiffer and therefore much less able to form a reliable seal when employed as O-rings. No consistent change of volume or density was observed; there was a systematic lowering of sample mass with tritium exposure. In addition, the significant radiolytic production of gas, mainly protium (H{sub 2}) and HT, by the samples when exposed to tritium was characterized by measuring total pressure in the container at the end of each exposure and by mass spectroscopy of a gas sample at the end of each exposure. The total pressure in the containers more than doubled after {approx}420 days tritium exposure.« less

  19. Tritium trinkets

    NASA Astrophysics Data System (ADS)

    Thornton, Brett F.; Burdette, Shawn C.

    2018-06-01

    Scientists take nomenclature seriously, but tritium was named in a casual aside. Brett F. Thornton and Shawn C. Burdette discuss the heavy, radioactive hydrogen isotope that is available for purchase online.

  20. Effect of the self-pumped limiter concept on the tritium fuel cycle

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

    Finn, P.A.; Sze, D.K.; Hassanein, A.

    1988-01-01

    The self-pumped limiter concept for impurity control of the plasma of a fusion reactor has a major impact on the design of the tritium systems. To achieve a sustained burn, conventional limiters and divertors remove large quantities of unburnt tritium and deuterium from the plasma which must be then recycled using a plasma processing system. The self-pumped limiter which does not remove the hydrogen species, does not require any plasma processing equipment. The blanket system and the coolant processing systems acquire greater importance with the use of this unconventional impurity control system. 3 refs., 2 figs.

  1. Tritium laboratory with multiple purposes at NIPNE Magurele Romania

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

    Matei, L.; Postolache, C.

    2008-07-15

    The Tritium Laboratory from NIPNE (Romania)) is part of Radioisotope Research and Production Center. The Tritium Laboratory has been in operation since 1960, and carries out R and D activities involving tritium sources in gaseous, liquids and solid state, provides specialized service to CANDU NPP Cernavoda (Romania)), and provides tritium assay services to internal and external customers. The paper presents the activities and perspectives of Tritium Laboratory and its performances in accordance with Quality System Management. (authors)

  2. Isotopic fractionation of tritium in biological systems.

    PubMed

    Le Goff, Pierre; Fromm, Michel; Vichot, Laurent; Badot, Pierre-Marie; Guétat, Philippe

    2014-04-01

    Isotopic fractionation of tritium is a highly relevant issue in radiation protection and requires certain radioecological considerations. Sound evaluation of this factor is indeed necessary to determine whether environmental compartments are enriched/depleted in tritium or if tritium is, on the contrary, isotopically well-distributed in a given system. The ubiquity of tritium and the standard analytical methods used to assay it may induce biases in both the measurement and the signification that is accorded to the so-called fractionation: based on an exhaustive review of the literature, we show how, sometimes large deviations may appear. It is shown that when comparing the non-exchangeable fraction of organically bound tritium (neOBT) to another fraction of tritium (e.g. tritiated water) the preparation of samples and the measurement of neOBT reported frequently led to underestimation of the ratio of tritium to hydrogen (T/H) in the non-exchangeable compartment by a factor of 5% to 50%. In the present study, corrections are proposed for most of the biological matrices studied so far. Nevertheless, the values of isotopic fractionation reported in the literature remain difficult to compare with each other, especially since the physical quantities and units often vary between authors. Some improvements are proposed to better define what should encompass the concepts of exchangeable and non-exchangeable fractions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Monitoring of tritium

    DOEpatents

    Corbett, James A.; Meacham, Sterling A.

    1981-01-01

    The fluid from a breeder nuclear reactor, which may be the sodium cooling fluid or the helium reactor-cover-gas, or the helium coolant of a gas-cooled reactor passes over the portion of the enclosure of a gaseous discharge device which is permeable to hydrogen and its isotopes. The tritium diffused into the discharge device is radioactive producing beta rays which ionize the gas (argon) in the discharge device. The tritium is monitored by measuring the ionization current produced when the sodium phase and the gas phase of the hydrogen isotopes within the enclosure are in equilibrium.

  4. [Mechanism of tritium persistence in porous media like clay minerals].

    PubMed

    Wu, Dong-Jie; Wang, Jin-Sheng; Teng, Yan-Guo; Zhang, Ke-Ni

    2011-03-01

    To investigate the mechanisms of tritium persistence in clay minerals, three types of clay soils (montmorillonite, kaolinite and illite) and tritiated water were used in this study to conduct the tritium sorption tests and the other related tests. Firstly, the ingredients, metal elements and heat properties of clay minerals were studied with some instrumental analysis methods, such as ICP and TG. Secondly, with a specially designed fractionation and condensation experiment, the adsorbed water, the interlayer water and the structural water in the clay minerals separated from the tritium sorption tests were fractionated for investigating the tritium distributions in the different types of adsorptive waters. Thirdly, the location and configuration of tritium adsorbed into the structure of clay minerals were studied with infrared spectrometry (IR) tests. And finally, the forces and mechanisms for driving tritium into the clay minerals were analyzed on the basis of the isotope effect of tritium and the above tests. Following conclusions have been reached: (1) The main reason for tritium persistence in clay minerals is the entrance of tritium into the adsorbed water, the interlayer water and the structural water in clay minerals. The percentage of tritium distributed in these three types of adsorptive water are in the range of 13.65% - 38.71%, 0.32% - 5.96%, 1.28% - 4.37% of the total tritium used in the corresponding test, respectively. The percentages are different for different types of clay minerals. (2) Tritium adsorbed onto clay minerals are existed in the forms of the tritiated hydroxyl radical (OT) and the tritiated water molecule (HTO). Tritium mainly exists in tritiated water molecule for adsorbed water and interlayer water, and in tritiated hydroxyl radical for structural water. (3) The forces and effects driving tritium into the clay minerals may include molecular dispersion, electric charge sorption, isotope exchange and tritium isotope effect.

  5. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target....77. (b) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg...

  6. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target....77. (b) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg...

  7. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target....77. (b) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg...

  8. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target....77. (b) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg...

  9. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target....77. (b) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg...

  10. Apparatus and method for stripping tritium from molten salt

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

    Holcomb, David E.; Wilson, Dane F.

    A method of stripping tritium from flowing stream of molten salt includes providing a tritium-separating membrane structure having a porous support, a nanoporous structural metal-ion diffusion barrier layer, and a gas-tight, nonporous palladium-bearing separative layer, directing the flowing stream of molten salt into contact with the palladium-bearing layer so that tritium contained within the molten salt is transported through the tritium-separating membrane structure, and contacting a sweep gas with the porous support for collecting the tritium.

  11. Use of Tritium Accelerator Mass Spectrometry for Tree Ring Analysis

    PubMed Central

    LOVE, ADAM H.; HUNT, JAMES R.; ROBERTS, MARK L.; SOUTHON, JOHN R.; CHIARAPPA - ZUCCA, MARINA L.; DINGLEY, KAREN H.

    2010-01-01

    Public concerns over the health effects associated with low-level and long-term exposure to tritium released from industrial point sources have generated the demand for better methods to evaluate historical tritium exposure levels for these communities. The cellulose of trees accurately reflects the tritium concentration in the source water and may contain the only historical record of tritium exposure. The tritium activity in the annual rings of a tree was measured using accelerator mass spectrometry to reconstruct historical annual averages of tritium exposure. Milligram-sized samples of the annual tree rings from a Tamarix located at the Nevada Test Site are used for validation of this methodology. The salt cedar was chosen since it had a single source of tritiated water that was well-characterized as it varied over time. The decay-corrected tritium activity of the water in which the salt cedar grew closely agrees with the organically bound tritium activity in its annual rings. This demonstrates that the milligram-sized samples used in tritium accelerator mass spectrometry are suited for reconstructing anthropogenic tritium levels in the environment. PMID:12144257

  12. Current status of tritium calorimetry at TLK

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

    Buekki-Deme, A.; Alecu, C.G.; Kloppe, B.

    2015-03-15

    Inside a tritium facility, calorimetry is an important analytical method as it is the only reference method for accountancy (it is based on the measurement of the heat generated by the radioactive decay). Presently, at Tritium Laboratory Karlsruhe (TLK), 4 calorimeters are in operation, one of isothermal type and three of inertial guidance control type (IGC). The volume of the calorimeters varies between 0.5 and 20.6 liters. About two years ago we started an extensive work to improve our calorimeters with regard to reliability and precision. We were forced to upgrade 3 of our 4 calorimeters due to the outdatedmore » interfaces and software. This work involved creating new LabView programs driving the devices, re-tuning control loops and replacing obsolete hardware components. In this paper we give a review on the current performance of our calorimeters, comparing it to recently available devices from the market and in the literature. We also show some ideas for a next generation calorimeter based on experiences with our IGC calorimeters and other devices reported in the literature. (authors)« less

  13. Technical/ administrative options for managing tritium MCL exceedances in P-area groundwater and Steel Creek

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

    Ross, J.

    2017-04-01

    This white paper was requested by the Core Team (United States Department of Energy [USDOE], United States Environmental Protection Agency [USEPA], and South Carolina Department of Health and Environmental Control [SCDHEC]) at the P-Area Groundwater (PAGW) Operable Unit (OU) Scoping Meeting held in January 2017 to discuss recent data and potential alternatives in support of a focused Corrective Measures Study/Feasibility Study (CMS/FS). This white paper presents an overview of the problem, and a range of technical and administrative options for addressing the tritium contamination in groundwater and Steel Creek. As tritium cannot be treated practicably, alternatives are limited to mediamore » transfer, containment and natural attenuation principally relying on radioactive decay. Using other groundwater OU decisions involving tritium as precedent, Savannah River Nuclear Solutions (SRNS) recommends that final tritium alternatives be evaluated in a CMS/FS, understanding that the likely preferred remedy will include natural attenuation with land use controls (LUCs). This is based on the inability to significantly reduce tritium impact to Steel Creek using an engineered solution as compared to natural attenuation. The timing of this evaluation could be conducted concurrently with the final remedy evaluation for volatile organic compounds (VOCs).« less

  14. Solid state tritium detector for biomedical applications

    NASA Astrophysics Data System (ADS)

    Gordon, J. S.; Farrell, R.; Daley, K.; Oakes, C. E.

    1994-08-01

    Radioactive labeling of proteins is a very important technique used in biomedical research to identify, isolate, and investigate the expression and properties of proteins in biological systems. In such procedures, the preferred radiolabel is often tritium. Presently, binding assays involving tritium are carried out using inconvenient and expensive techniques which rely on the use of scintillation fluid counting systems. This traditional method involves both time-consuming laboratory protocols and the generation of substantial quantities of radioactive and chemical waste. We have developed a novel technology to measure the tritium content of biological specimens that does not rely on scintillation fluids. The tritiated samples can be positioned directly under a large area, monolithic array of specially prepared avalanche photodiodes (APDs) which record the tritium activity distribution at each point within the field of view of the array. The 1 mm(sup 2) sensing elements exhibit an intrinsic tritium beta detection efficiency of 27% with high gain uniformity and very low cross talk.

  15. Calibration of a transient transport model to tritium data in streams and simulation of groundwater ages in the western Lake Taupo catchment, New Zealand

    NASA Astrophysics Data System (ADS)

    Gusyev, M. A.; Toews, M.; Morgenstern, U.; Stewart, M.; White, P.; Daughney, C.; Hadfield, J.

    2013-03-01

    Here we present a general approach of calibrating transient transport models to tritium concentrations in river waters developed for the MT3DMS/MODFLOW model of the western Lake Taupo catchment, New Zealand. Tritium has a known pulse-shaped input to groundwater systems due to the bomb tritium in the early 1960s and, with its radioactive half-life of 12.32 yr, allows for the determination of the groundwater age. In the transport model, the tritium input (measured in rainfall) passes through the groundwater system, and the simulated tritium concentrations are matched to the measured tritium concentrations in the river and stream outlets for the Waihaha, Whanganui, Whareroa, Kuratau and Omori catchments from 2000-2007. For the Kuratau River, tritium was also measured between 1960 and 1970, which allowed us to fine-tune the transport model for the simulated bomb-peak tritium concentrations. In order to incorporate small surface water features in detail, an 80 m uniform grid cell size was selected in the steady-state MODFLOW model for the model area of 1072 km2. The groundwater flow model was first calibrated to groundwater levels and stream baseflow observations. Then, the transient tritium transport MT3DMS model was matched to the measured tritium concentrations in streams and rivers, which are the natural discharge of the groundwater system. The tritium concentrations in the rivers and streams correspond to the residence time of the water in the groundwater system (groundwater age) and mixing of water with different age. The transport model output showed a good agreement with the measured tritium values. Finally, the tritium-calibrated MT3DMS model is applied to simulate groundwater ages, which are used to obtain groundwater age distributions with mean residence times (MRTs) in streams and rivers for the five catchments. The effect of regional and local hydrogeology on the simulated groundwater ages is investigated by demonstrating groundwater ages at five model

  16. Tritium release during nuclear power operation in China.

    PubMed

    Yang, D J; Chen, X Q; Li, B

    2012-06-01

    Overviews were evaluated of tritium releases and related doses to the public from airborne and liquid effluents from nuclear power plants on the mainland of China before 2009. The differences between tritium releases from various nuclear power plants were also evaluated. The tritium releases are mainly from liquid pathways for pressurised water reactors, but tritium releases between airborne and liquid effluents are comparable for heavy water reactors. The airborne release from a heavy water reactor is obviously higher than that from a pressurised water reactor.

  17. Tritium hydrology of the Mississippi River basin

    USGS Publications Warehouse

    Michel, R.L.

    2004-01-01

    In the early 1960s, the US Geological Survey began routinely analysing river water samples for tritium concentrations at locations within the Mississippi River basin. The sites included the main stem of the Mississippi River (at Luling Ferry, Louisiana), and three of its major tributaries, the Ohio River (at Markland Dam, Kentucky), the upper Missouri River (at Nebraska City, Nebraska) and the Arkansas River (near Van Buren, Arkansas). The measurements cover the period during the peak of the bomb-produced tritium transient when tritium concentrations in precipitation rose above natural levels by two to three orders of magnitude. Using measurements of tritium concentrations in precipitation, a tritium input function was established for the river basins above the Ohio River, Missouri River and Arkansas River sampling locations. Owing to the extent of the basin above the Luling Ferry site, no input function was developed for that location. The input functions for the Ohio and Missouri Rivers were then used in a two-component mixing model to estimate residence times of water within these two basins. (The Arkansas River was not modelled because of extremely large yearly variations in flow during the peak of the tritium transient.) The two components used were: (i) recent precipitation (prompt outflow) and (ii) waters derived from the long-term groundwater reservoir of the basin. The tritium concentration of the second component is a function of the atmospheric input and the residence times of the groundwaters within the basin. Using yearly time periods, the parameters of the model were varied until a best fit was obtained between modelled and measured tritium data. The results from the model indicate that about 40% of the flow in the Ohio River was from prompt outflow, as compared with 10% for the Missouri River. Mean residence times of 10 years were calculated for the groundwater component of the Ohio River versus 4 years for the Missouri River. The mass flux of

  18. Technical and Scientific Aspects of the JET Trace-Tritium Experimental Campaign

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

    Jones, T.T.C.; Brennan, D; Pearce, R.J.H.

    The JET Trace Tritium (TTE) programme marked the first use of tritium in experiments under the managerial control of UKAEA, which operates the JET Facility on behalf of EFDA. The introduction of tritium into the plasma by gas fuelling and neutral beam injection, even in trace quantities, required the mobilisation of gram-quantities of tritium gas from the Active Gas Handling System (AGHS) product storage units into the supply lines connected to the torus gas valve and the neutral beam injectors. All systems for DT gas handling, recovery and reprocessing were therefore recommissioned and operating procedures re-established, involving extensive operations staffmore » training. The validation of Key Safety Related Equipment (KSRE) is described with reference to specific examples. The differences between requirements for TTE and full DT operations are shown to be relatively small. The scientific motivation for TTE, such as the possibility to obtain high-quality measurements in key areas such as fuel-ion transport and fast ion dynamics, is described, and the re-establishment and development of JET's 14MeV neutron diagnostic capability for TTE and future DT campaigns are outlined. Some scientific highlights from the TTE campaign are presented.« less

  19. Cosmogenic production of tritium in dark matter detectors

    NASA Astrophysics Data System (ADS)

    Amaré, J.; Castel, J.; Cebrián, S.; Coarasa, I.; Cuesta, C.; Dafni, T.; Galán, J.; García, E.; Garza, J. G.; Iguaz, F. J.; Irastorza, I. G.; Luzón, G.; Martínez, M.; Mirallas, H.; Oliván, M. A.; Ortigoza, Y.; Ortiz de Solórzano, A.; Puimedón, J.; Ruiz-Chóliz, E.; Sarsa, M. L.; Villar, J. A.; Villar, P.

    2018-01-01

    The direct detection of dark matter particles requires ultra-low background conditions at energies below a few tens of keV. Radioactive isotopes are produced via cosmogenic activation in detectors and other materials and those isotopes constitute a background source which has to be under control. In particular, tritium is specially relevant due to its decay properties (very low endpoint energy and long half-life) when induced in the detector medium, and because it can be generated in any material as a spallation product. Quantification of cosmogenic production of tritium is not straightforward, neither experimentally nor by calculations. In this work, a method for the calculation of production rates at sea level has been developed and applied to some of the materials typically used as targets in dark matter detectors (germanium, sodium iodide, argon and neon); it is based on a selected description of tritium production cross sections over the entire energy range of cosmic nucleons. Results have been compared to available data in the literature, either based on other calculations or from measurements. The obtained tritium production rates, ranging from a few tens to a few hundreds of nuclei per kg and per day at sea level, point to a significant contribution to the background in dark matter experiments, requiring the application of specific protocols for target material purification, material storing underground and limiting the time the detector is on surface during the building process in order to minimize the exposure to the most dangerous cosmic ray components.

  20. Tritium migration to the surfaces of Type 316 stainless steel; aluminum 6061; and oxygen-free, high-conductivity copper

    DOE PAGES

    Sharpe, M.; Shmayda, W. T.; Schroder, W. U.

    2016-05-25

    The migration of tritium to the surfaces of aluminum 6061, oxygen-free, high-conductivity copper (OFHC), and stainless-steel 316 from the bulk metal was studied using low-pressure Tonks–Langmuir argon plasma. The plasma is shown to be effective at removing tritium from metal surfaces in a controlled manner. Tritium is removed in decreasing quantities with successive plasma exposures, which suggests a depletion of the surface and near-surface tritium inventories. A diffusion model was developed to predict tritium migration from the bulk and its accumulation in the water layers present on the metal surface. The model reproduces the rate of tritium re-growth on themore » surface for all three metals and can be used to calculate the triton solubility in the water layers present on metal surfaces. The ratio of surface-to-bulk solubilities at the water-layer/bulk-metal interface uniquely determines the concentration ratio between these two media. Removing the tritium-rich water layers induces tritium to migrate from the bulk to the surface. Furthermore, this process is driven by a concentration gradient that develops in the bulk because of the perturbation on the surface.« less

  1. Correlation of rates of tritium migration through porous concrete

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

    Fukada, S.; Katayama, K.; Takeishi, T.

    In a nuclear facility when tritium leaks from a glovebox to room accidentally, an atmosphere detritiation system (ADS) starts operating, and HTO released is recovered by ADS. ADS starts when tritium activity in air becomes higher than its controlled level. Before ADS operates, the laboratory walls are the final enclosure facing tritium and are usually made of porous concrete coated with a hydrophobic paint. In the present study, previous data on the diffusivity and adsorption coefficient of concrete and paints are reviewed. Tritium penetrates and migrates into concrete by following 3 ways. First, gaseous HT or T{sub 2} easily penetratesmore » into porous concrete. Its diffusivity is almost equal to that of H{sub 2}. When a gaseous molecule diffuses through pores with a smaller diameter than a mean free path, its migration rate is described by the Knudsen diffusion formula. The second mechanism is H{sub 2}O vapor diffusion in pores. Concrete holds a lot of structural water. Therefore, H{sub 2}O or HTO vapor can diffuse inside concrete pores along with adsorption-desorption and isotopic exchange with structural water, which is the third mechanism. Literature shows that the diffusivity of HTO through the epoxy-resin paint is determined as D(HTO)=1.0*10{sup -16} m{sup 2}/s. We have used this data to set a model and we have applied it to estimate residual tritium in laboratory walls. We have considered 2 accidental cases and a normal case: first, ADS starts operating 1 hour after 100 Ci HTO is released in the room, secondly, ADS starts 24 hours after 100 Ci HTO release and thirdly, when the walls are exposed to HTO for 10 years of normal operation. It appears that the immediate start up of ADS is indispensable for safety.« less

  2. Tritium in Exit Signs | RadTown USA | US EPA

    EPA Pesticide Factsheets

    2018-05-01

    Many exit signs contain tritium to light the sign without batteries or electricity, which allows it to remain lit if the power goes out. Tritium is most dangerous when it is inhaled or swallowed. Never tamper with a tritium exit sign.

  3. The oxygen enhancement ratio for single- and double-strand breaks induced by tritium incorporated in DNA of cultured human T1 cells. Impact of the transmutation effect.

    PubMed

    Tisljar-Lentulis, G; Henneberg, P; Feinendegen, L E; Commerford, S L

    1983-04-01

    The effect of oxygen, expressed as the oxygen enhancement ratio (OER), on the number of single-strand breaks (SSB) and double-strand breaks (DSB) induced in DNA by the radioactive decay of tritium was measured in human T1 cells whose DNA had been labeled with tritium at carbon atom number 6 of thymidine. Decays were accumulated in vivo under aerobic conditions at 0-1 degrees C and at -196 degrees C and in a nitrogen atmosphere at 0-1 degrees C. The number of SSB and DSB produced was analyzed by sucrose gradient centrifugation. For each tritium decay there were 0.25 DSB in cells exposed to air at 0-1 degrees C and 0.07 in cells kept under nitrogen, indicating an OER of 3.6, a value expected for such low-LET radiation. However, for each tritium decay there were 1.25 SSB in cells exposed to air at 0-1 degrees C and 0.76 in cells kept under nitrogen indicating an OER of only 1.7. The corresponding values for 60Co gamma radiation, expressed as SSB per 100 eV absorbed energy, were 4.5 and 1.0, giving an OER of 4.5. The low OER value found for SSB induced by tritium decay can be explained if 31% of the total SSB produced in air result from transmutation by a mechanism which does not produce DSB and is unaffected by oxygen.

  4. Portable Intelligent Tritium in Air Monitor

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

    Purghel, L.; Calin, M.R.; Bartos, D.

    2005-07-15

    The tritium detection method used for this monitor is original, patented in Romania. The detection unit consists of a single ionization chamber, a special fast preamplifier and a dedicated software associated to the detection unit, for signals processing. Some results concerning the tritium in relative strong gamma-ray fields are presented.

  5. Effect of Tritium on Cracking Threshold in 7075 Aluminum

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

    Duncan, A.; Morgan, M.

    The effect of long-term exposure to tritium gas on the cracking threshold (K TH) of 7075 Aluminum Alloy was investigated. The alloy is the material of construction for a cell used to contain tritium in an accelerator at Jefferson Laboratory designed for inelastic scattering experiments on nucleons. The primary safety concerns for the Jefferson Laboratory tritium cell is a tritium leak due to mechanical failure of windows from hydrogen isotope embrittlement, radiation damage, or loss of target integrity from accidental excessive beam heating due to failure of the raster or grossly mis-steered beam. Experiments were conducted to investigate the potentialmore » for embrittlement of the 7075 Aluminum alloy from tritium gas.« less

  6. Study on Tritium Removal Performance by Gas Separation Membrane with Reflux Flow for Tritium Removal System of Fusion Reactor

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

    Iwai, Yasunori; Yamanishi, Toshihiko; Hayashi, Takumi

    2005-07-15

    Addition of gas separation membrane process into the usual tritium removal process from an indoor atmosphere is attractive for a fusion plant, where a large amount of atmosphere should be processed. As a manner to improve the partial pressure difference between feed and permeated side, intended reflux of vapor and the hydrogen concentrated at permeated side is conceived to enlarge the partial pressure difference. Membrane separation with reflux flow has been proposed as an attractive process to enhance the recovery ratio of tritium component. Effect of reflux on the recovery ratio of tritium component was evaluated by numerical analysis. Themore » effect of reflux on separation performance becomes striking as the target species have higher permeability coefficients. Hence, the gas separation by membrane with reflux flow is favorable for tritium recovery.« less

  7. 2016 Accomplishments. Tritium aging studies on stainless steel. Forging process effects on the fracture toughness properties of tritium-precharged stainless steel

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

    Morgan, Michael J.

    Forged austenitic stainless steels are used as the materials of construction for pressure vessels designed to contain tritium at high pressure. These steels are highly resistant to tritium-assisted fracture but their resistance can depend on the details of the forging microstructure. During FY16, the effects of forging strain rate and deformation temperature on the fracture toughness properties of tritium-exposed-and-aged Type 304L stainless steel were studied. Forgings were produced from a single heat of steel using four types of production forging equipment – hydraulic press, mechanical press, screw press, and high-energy-rate forging (HERF). Each machine imparted a different nominal strain ratemore » during the deformation. The objective of the study was to characterize the J-Integral fracture toughness properties as a function of the industrial strain rate and temperature. The second objective was to measure the effects of tritium and decay helium on toughness. Tritium and decay helium effects were measured by thermally precharging the as-forged specimens with tritium gas at 34.5 MPa and 350°C and aging for up to five years at -80°C to build-in decay helium prior to testing. The results of this study show that the fracture toughness properties of the as-forged steels vary with forging strain rate and forging temperature. The effect is largely due to yield strength as the higher-strength forgings had the lower toughness values. For non-charged specimens, fracture toughness properties were improved by forging at 871°C versus 816°C and Screw-Press forgings tended to have lower fracture toughness values than the other forgings. Tritium exposures reduced the fracture toughness values remarkably to fracture toughness values averaging 10-20% of as-forged values. However, forging strain rate and temperature had little or no effect on the fracture toughness after tritium precharging and aging. The result was confirmed by fractography which indicated that

  8. Evaluation of Tritium Content and Release from Pressurized Water Reactor Fuel Cladding

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

    Robinson, Sharon M.; Chattin, Marc Rhea; Giaquinto, Joseph

    2015-09-01

    It is expected that tritium pretreatment will be required in future reprocessing plants to prevent the release of tritium to the environment (except for long-cooled fuels). To design and operate future reprocessing plants in a safe and environmentally compliant manner, the amount and form of tritium in the used nuclear fuel (UNF) must be understood and quantified. Tritium in light water reactor (LWR) fuel is dispersed between the fuel matrix and the fuel cladding, and some tritium may be in the plenum, probably as tritium labelled water (THO) or T 2O. In a standard processing flowsheet, tritium management would bemore » accomplished by treatment of liquid streams within the plant. Pretreating the fuel prior to dissolution to release the tritium into a single off-gas stream could simplify tritium management, so the removal of tritium in the liquid streams throughout the plant may not be required. The fraction of tritium remaining in the cladding may be reduced as a result of tritium pretreatment. Since Zircaloy® cladding makes up roughly 25% by mass of UNF in the United States, processes are being considered to reduce the volume of reprocessing waste for Zircaloy® clad fuel by recovering the zirconium from the cladding for reuse. These recycle processes could release the tritium in the cladding. For Zircaloy-clad fuels from light water reactors, the tritium produced from ternary fission and other sources is expected to be divided between the fuel, where it is generated, and the cladding. It has been previously documented that a fraction of the tritium produced in uranium oxide fuel from LWRs can migrate and become trapped in the cladding. Estimates of the percentage of tritium in the cladding typically range from 0–96%. There is relatively limited data on how the tritium content of the cladding varies with burnup and fuel history (temperature, power, etc.) and how pretreatment impacts its release. To gain a better understanding of how tritium in cladding will

  9. New Safety and Technical Challenges and Operational Experience on the JET First Trace Tritium Experiment

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

    Pearce, R.J.H.; Bell, A.C.; Brennan, D.

    'Trace Tritium Experiments' (TTE) were successfully performed on JET in 2003. The Campaign marked the first use of tritium in JET plasmas since the Deuterium-Tritium Experiment (DTE1) Campaign in 1997, and was the first use of tritium in experiments under the EFDA organisation with the UKAEA as JET Operator. The safety and regulatory preparations for the experiment were extensive. Since JET has been operated by the UKAEA the operations have followed the model of a licensed nuclear site. The safe operation of the JET torus is demonstrated in a safety case. Key Safety Management Requirement (KSMR) and Key Safety Relatedmore » Equipment (KSRE) are identified in the Safety Case for DT operation. The safe operation of the torus is within the bounds of, and under the control of, an Authority to Operate (ATO). New technical challenges were presented by the need to inject and account for small quantities of tritium in very short pulses ({approx}80ms), with an accurate time stamp. The safety and operational management of the campaign are described. Valuable lessons were learned which would help in running future experiments. It is concluded that JET is in a strong position to run future trace tritium and full DT discharges.« less

  10. Studying of tritium content in snowpack of Degelen mountain range.

    PubMed

    Turchenko, D V; Lukashenko, S N; Aidarkhanov, A O; Lyakhova, O N

    2014-06-01

    The paper presents the results of investigation of tritium content in the layers of snow located in the streambeds of the "Degelen" massif contaminated with tritium. The objects of investigation were selected watercourses Karabulak, Uzynbulak, Aktybai located beyond the "Degelen" site. We studied the spatial distribution of tritium relative to the streambed of watercourses and defined the borders of the snow cover contamination. In the centre of the creek watercourses the snow contamination in the surface layer is as high as 40 000 Bq/L. The values of the background levels of tritium in areas not related to the streambed, which range from 40 to 50 Bq/L. The results of snow cover measurements in different seasonal periods were compared. The main mechanisms causing tritium transfer in snow were examined and identified. The most important mechanism of tritium transfer in the streams is tritium emanation from ice or soil surface. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Using the tritium plasma experiment to evaluate ITER PFC safety

    NASA Astrophysics Data System (ADS)

    Longhurst, Glen R.; Anderl, Robert A.; Bartlit, John R.; Causey, Rion A.; Haines, John R.

    1993-06-01

    The Tritium Plasma Experiment was assembled at Sandia National Laboratories, Livermore and is being moved to the Tritium Systems Test Assembly facility at Los Alamos National Laboratory to investigate interactions between dense plasmas at low energies and plasma-facing component materials. This apparatus has the unique capabilty of replicating plasma conditions in a tokamak divertor with particle flux densities of 2 × 1023 ions/m2.s and a plasma temperature of about 15 eV using a plasma that includes tritium. An experimental program has been initiated using the Tritium Plasma Experiment to examine safety issues related to tritium in plasma-facing components, particularly the ITER divertor. Those issues include tritium retention and release characteristics, tritium permeation rates and transient times to coolant streams, surface modification and erosion by the plasma, the effects of thermal loads and cycling, and particulate production. An industrial consortium led by McDonnell Douglas will design and fabricate the test fixtures.

  12. Monitoring and management of tritium from the nuclear power plant effluent

    NASA Astrophysics Data System (ADS)

    Zhang, Qiaoe; Liu, Ting; Yang, Lili; Meng, De; Song, Dahu

    2018-01-01

    It is important to regulate tritium nuclides from the nuclear power plant effluent, the paper briefly analyzes the main source of tritium, and the regulatory requirements associated with tritium in our country and the United States. The monitoring methods of tritium from the nuclear power plant effluent are described, and the purpose to give some advice to our national nuclear power plant about the effluent of tritium monitoring and management.

  13. In situ measurement of tritium permeation through stainless steel

    NASA Astrophysics Data System (ADS)

    Luscher, Walter G.; Senor, David J.; Clayton, Kevin K.; Longhurst, Glen R.

    2013-06-01

    The TMIST-2 irradiation experiment was conducted in the Advanced Test Reactor at Idaho National Laboratory to evaluate tritium permeation through Type 316 stainless steel (316 SS). The interior of a 316 SS seamless tube specimen was exposed to a 4He carrier gas mixed with a specified quantity of tritium (T2) to yield partial pressures of 0.1, 5, and 50 Pa at 292 °C and 330 °C. In situ tritium permeation measurements were made by passing a He-Ne sweep gas over the outer surface of the specimen to carry the permeated tritium to a bubbler column for liquid scintillation counting. Results from in situ permeation measurements were compared with predictions based on an ex-reactor permeation correlation in the literature. In situ permeation data were also used to derive an in-reactor permeation correlation as a function of temperature and pressure over the ranges considered in this study. In addition, the triton recoil contribution to tritium permeation, which results from the transmutation of 3He to T, was also evaluated by introducing a 4He carrier gas mixed with 3He at a partial pressure of 1013 Pa at 330 °C. Less than 3% of the tritium resulting from 3He transmutation contributed to tritium permeation.

  14. Modelling the distribution of tritium in groundwater across South Africa to assess the vulnerability and sustainability of groundwater resources in response to climate change

    NASA Astrophysics Data System (ADS)

    van Rooyen, Jared; Miller, Jodie; Watson, Andrew; Butler, Mike

    2017-04-01

    Groundwater is critical for sustaining human populations, especially in semi-arid to arid areas, where surface water availability is low. Shallow groundwater is usually abstracted for this purpose because it is the easiest to access and assumed to be renewable and regularly recharged by precipitation. Renewable, regularly recharged groundwater is also called modern groundwater, ie groundwater that has recently been in contact with the atmosphere. Tritium can be used to determine whether or not a groundwater resource is modern because the half-life of tritium is only 12.36 years and tritium is dominantly produced in the upper atmosphere and not in the rock mass. For this reason, groundwater with detectable tritium activities likely has a residence age of less than 50 years. In this study, tritium activities in 277 boreholes distributed across South Africa were used to develop a national model for tritium activity in groundwater in order to establish the extent of modern groundwater across South Africa. The tritium model was combined with modelled depth to water using 3079 measured static water levels obtained from the National Groundwater Archive and validated against a separate set of 40 tritium activities along the west coast of South Africa. The model showed good agreement with the distribution of rainfall which has been previously documented across the globe (Gleeson et al., 2015), although the arid Karoo basin in south west South Africa shows higher than expected tritium levels given the very low regional precipitation levels. To assess the vulnerability of groundwater to degradation in quality and quantity, the tritium model was incorporated into a multi-criteria evaluation (MCE) model which incorporated other indicators of groundwater stress including mean annual precipitation, mean annual surface temperature, electrical conductivity (as a proxy for groundwater salinization), potential evaporation, population density and cultivated land usage. The MCE model

  15. EFFECT OF TRITIUM AND DECAY HELIUM ON WELDMENT FRACTURE TOUGHNESS

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

    Morgan, M; Scott West, S; Michael Tosten, M

    2006-09-26

    The fracture toughness data collected in this study are needed to assess the long-term effects of tritium and its decay product on tritium reservoirs. The results show that tritium and decay helium have negative effects on the fracture toughness properties of stainless steel and its weldments. The data and report from this study has been included in a material property database for use in tritium reservoir modeling efforts like the Technology Investment Program ''Lifecycle Engineering for Tritium Reservoirs''. A number of conclusions can be drawn from the data: (1) For unexposed Type 304L stainless steel, the fracture toughness of weldmentsmore » was two to three times higher than the base metal toughness. (2) Tritium exposure lowered the fracture toughness properties of both base metals and weldments. This was characterized by lower J{sub Q} values and lower J-da curves. (3) Tritium-exposed-and-aged base metals and weldments had lower fracture toughness values than unexposed ones but still retained good toughness properties.« less

  16. Development of a Tritium Extruder for ITER Pellet Injection

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

    M.J. Gouge; P.W. Fisher

    As part of the International Thermonuclear Experimental Reactor (ITER) plasma fueling development program, Oak Ridge National Laboratory (ORNL) has fabricated a pellet injection system to test the mechanical and thermal properties of extruded tritium. Hydrogenic pellets will be used in ITER to sustain the fusion power in the plasma core and may be crucial in reducing first-wall tritium inventories by a process of "isotopic fueling" in which tritium-rich pellets fuel the burning plasma core and deuterium gas fuels the edge. This repeating single-stage pneumatic pellet injector, called the Tritium-Proof-of-Principle Phase II (TPOP-II) Pellet Injector, has a piston-driven mechanical extruder andmore » is designed to extrude and accelerate hydrogenic pellets sized for the ITER device. The TPOP-II program has the following development goals: evaluate the feasibility of extruding tritium and deuterium-tritium (D-T) mixtures for use in future pellet injection systems; determine the mechanical and thermal properties of tritium and D-T extrusions; integrate, test, and evaluate the extruder in a repeating, single-stage light gas gun that is sized for the ITER application (pellet diameter -7 to 8 mm); evaluate options for recycling propellant and extruder exhaust gas; and evaluate operability and reliability of ITER prototypical fueling systems in an environment of significant tritium inventory that requires secondary and room containment systems. In tests with deuterium feed at ORNL, up to 13 pellets per extrusion have been extruded at rates up to 1 Hz and accelerated to speeds of 1.0 to 1.1 km/s, using hydrogen propellant gas at a supply pressure of 65 bar. Initially, deuterium pellets 7.5 mm in diameter and 11 mm in length were produced-the largest cryogenic pellets produced by the fusion program to date. These pellets represent about a 10% density perturbation to ITER. Subsequently, the extruder nozzle was modified to produce pellets that are almost 7.5-mm right

  17. Measurement of tritium penetration through concrete material covered by various paints coating

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

    Edao, Y.; Kawamura, Y.; Kurata, R.

    The present study aims at obtaining fundamental data on tritium migration in porous materials, which include soaking effect, interaction between tritium and cement paste coated with paints and transient tritium sorption in porous cement. The amounts of tritium penetrated into or released from cement paste with epoxy and urethane paint coatings were measured. The tritium penetration amounts were increased with the HTO (tritiated water) exposure time. Time to achieve a saturated value of tritium sorption was more than 60 days for cement paste coated with epoxy paint and with urethane paint, while that for cement paste without any paint coatingmore » took 2 days to achieve it. The effect of tritium permeation reduction by the epoxy paint was higher than that of the urethane. Although their paint coatings were effective for reduction of tritium penetration through the cement paste which was exposed to HTO for a short period, it was found that the amount of tritium trapped in the paints became large for a long period. Tritium penetration rates were estimated by an analysis of one-dimensional diffusion in the axial direction of a thickness of a sample. Obtained data were helpful for evaluation of tritium contamination and decontamination. (authors)« less

  18. Neutral Beam Injection in the JET Trace Tritium Experiment

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

    Surrey, E.; Ciric, D.; Cox, S. J.

    Operation of the JET Neutral Beam Injectors with tritium is described. Supplying the tritium feed via the special electrically grounded gas feed compromised the performance of the up-graded high current triode Positive Ion Neutral Injectors (PINI) due to gas starvation of the source and the methods adopted to ameliorate this effect are described. A total of 362 PINI beam pulses were requested, circulating a total of 4.73g tritium, of which 9.3mg was injected into the torus. Safety considerations required a continuous, cumulative total to be maintained of the mass of tritium adsorbed onto the cryo-pumping panel; a daily limit ofmore » 0.5g was adopted for the Trace Tritium Experiment (TTE). A subsequent clean up phase using 115keV deuterium beams completed the isotopic exchange of components in the beamline.« less

  19. Tritium power source for long-lived sensors

    NASA Astrophysics Data System (ADS)

    Litz, M. S.; Katsis, D. C.; Russo, J. A.; Carroll, J. J.

    2014-06-01

    A tritium-based indirect converting photovoltaic (PV) power source has been designed and prototyped as a long-lived (~15 years) power source for sensor networks. Tritium is a biologically benign beta emitter and low-cost isotope acquired from commercial vendors for this purpose. The power source combines tritium encapsulated with a radioluminescent phosphor coupled to a commercial PV cell. The tritium, phosphor, and PV components are packaged inside a BA5590-style military-model enclosure. The package has been approved by the nuclear regulatory commission (NRC) for use by DOD. The power source is designed to produce 100μW electrical power for an unattended radiation sensor (scintillator and avalanche photodiode) that can detect a 20 μCi source of 137Cs at three meters. This beta emitting indirect photon conversion design is presented as step towards the development of practical, logistically acceptable, lowcost long-lived compact power sources for unattended sensor applications in battlefield awareness and environmental detection.

  20. Tritium glovebox stripper system seismic design evaluation

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

    Grinnell, J. J.; Klein, J. E.

    2015-09-01

    The use of glovebox confinement at US Department of Energy (DOE) tritium facilities has been discussed in numerous publications. Glovebox confinement protects the workers from radioactive material (especially tritium oxide), provides an inert atmosphere for prevention of flammable gas mixtures and deflagrations, and allows recovery of tritium released from the process into the glovebox when a glovebox stripper system (GBSS) is part of the design. Tritium recovery from the glovebox atmosphere reduces emissions from the facility and the radiological dose to the public. Location of US DOE defense programs facilities away from public boundaries also aids in reducing radiological dosesmore » to the public. This is a study based upon design concepts to identify issues and considerations for design of a Seismic GBSS. Safety requirements and analysis should be considered preliminary. Safety requirements for design of GBSS should be developed and finalized as a part of the final design process.« less

  1. The Concentration Of Tritium In Urine And Internal Radiation Dose Estimation Of PTNBR Radiation Workers

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

    Tjahaja, Poppy Intan; Sukmabuana, Putu; Aisyah, Neneng Nur

    2010-12-23

    The operation of Triga 2000 reactor in Nuclear Technology Center for Materials and Radiometry (PTNBR BATAN) normally produce tritium radionuclide which is the activation product of deuterium atom in reactor primary cooling water. According to previous monitoring, tritium was detected with the concentration of 8.236{+-}0.677 kBq/L and 1.704{+-}0.046 Bq/L in the primary cooling water and in reactor hall air, respectively. The tritium in reactor hall air chronically can be inhaled by the workers. In this research, tritium content in radiation workers' urine was determined to estimate the internal radiation doses received by the workers. About 50-100 mL of urine samplesmore » were collected from 48 PTNBR workers that is classified as 24 radiation workers and 24 administration staffs as a control. Urine samples of 25 mL were then prepared by active charcoal and KMnO{sub 4} addition and followed with complete distillation. The 2 mL of distillate was added with 13 mL scintillator, shaked vigorously and remained in cool and dark condition for about 24 hours. The tritium in the samples was then measured using liquid scintillation counter (LSC) for 1 hour. From the measurement results it was obtained that the tritium concentration in the urine of radiation workers were in the range of not detected and 5.191 Bq/mL, whereas in the administration staffs the concentration were between not detected and 4.607 Bq/mL. Internally radiation doses were calculated using the tritium concentration data, and it was found the averages about 0.602 {mu}Sv/year and 0.532 {mu}Sv/year for radiation workers and administration staffs, respectively. The doses received by the workers were lower than that of the permissible doses from tritium, i.e. 40 {mu}Sv/year.« less

  2. Tritium in [15O]water, its identification and removal.

    PubMed

    Sasaki, T; Ishii, S; Tomiyoshi, K; Ido, T; Miyauchi, J; Senda, M

    2000-02-01

    The present investigation was undertaken to identify the long-lived radionuclide and its chemical forms existing in [15O]water which was synthesized from 15O produced by the nuclear reaction 14N(d,n)15O, and to develop a method for its removal to facilitate radioactive waste disposal. The long-lived nuclide was identified as tritium based on a comparison of its physical half-life and the energy spectrum of beta-rays with those of tritium. The major chemical form of tritium in the target gas was estimated to be molecular hydrogen. The tritium radioactivity was completely removed without a serious loss occurring to the yield of [15O]water by passing the irradiated target gas over a heated palladium catalyst followed by a calcium chloride column before the final synthesis of the [15O]water. This provided a practical way of removing tritium from the [15O]water.

  3. Incorporating biological control into IPM decision making

    USDA-ARS?s Scientific Manuscript database

    Of the many ways biological control can be incorporated into Integrated Pest Management (IPM) programs, natural enemy thresholds are arguably most easily adopted by stakeholders. Integration of natural enemy thresholds into IPM programs requires ecological and cost/benefit crop production data, thr...

  4. Tritium, deuterium, and helium permeation through EPDM O-rings

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

    Swansiger, W.A.

    1992-03-01

    This paper discusses tritium permeabilities determined at room temperature, 1.0 MPa (150 psia) tritium for three 23.4 cm diameter EPDM (ethylene-propylene-diene monomer) O-rings using a full-scale mock-up of the Al-SX shipping container seal geometry. The AL-SX container is being developed by Sandia National Laboratories for shipping tritium reservoirs. To determine the tritium permeation rate as a function of temperature, a 50.8 mm diameter EPDM O-ring was tested from room temperature to 150{degrees}C at a pressure of 1.0 MPa. Additional permeation measurements were made under the following test conditions: deuterium and helium-4 at room temperature and a pressure of 1.0 MPamore » using the full-scale AL-SX fixture, tritium from 0.1 MPa to 1.0 MPa at 142{degrees}C using the 50.8 mm fixture, and deuterium form room temperature to 150{degrees}C at a pressure of 1.0 MPa using the three full-scale O-rings showed the average room temperature, 1.0 MPa steady state tritium permeation rate to be about 1 {times} 10{sup {minus}2} Pa-liter/sec (7.6 {times} 10{sup {minus}5} torr-liter/sec or 1 {times} 10{sup {minus}4} std cc/sec), well within the allowable limit of 7.1 {times} 10{sup {minus}2} Pa-liter/sec for tritium release form the AL-SX container.« less

  5. Tritium proof-of-principle pellet injector: Phase 2

    NASA Astrophysics Data System (ADS)

    Fisher, P. W.; Gouge, M. J.

    1995-03-01

    As part of the International Thermonuclear Engineering Reactor (ITER) plasma fueling development program, Oak Ridge National Laboratory (ORNL) has fabricated a pellet injection system to test the mechanical and thermal properties of extruded tritium. This repeating, single-stage, pneumatic injector, called the Tritium-Proof-of-Principle Phase-2 (TPOP-2) Pellet Injector, has a piston-driven mechanical extruder and is designed to extrude hydrogenic pellets sized for the ITER device. The TPOP-II program has the following development goals: evaluate the feasibility of extruding tritium and DT mixtures for use in future pellet injection systems; determine the mechanical and thermal properties of tritium and DT extrusions; integrate, test and evaluate the extruder in a repeating, single-stage light gas gun sized for the ITER application (pellet diameter approximately 7-8 mm); evaluate options for recycling propellant and extruder exhaust gas; evaluate operability and reliability of ITER prototypical fueling systems in an environment of significant tritium inventory requiring secondary and room containment systems. In initial tests with deuterium feed at ORNL, up to thirteen pellets have been extruded at rates up to 1 Hz and accelerated to speeds of order 1.0-1.1 km/s using hydrogen propellant gas at a supply pressure of 65 bar. The pellets are typically 7.4 mm in diameter and up to 11 mm in length and are the largest cryogenic pellets produced by the fusion program to date. These pellets represent about a 11% density perturbation to ITER. Hydrogenic pellets will be used in ITER to sustain the fusion power in the plasma core and may be crucial in reducing first wall tritium inventories by a process called isotopic fueling where tritium-rich pellets fuel the burning plasma core and deuterium gas fuels the edge.

  6. On the conversion of tritium units to mass fractions for hydrologic applications

    USGS Publications Warehouse

    Stonestrom, David A.; Andraski, Brian J.; Cooper, Clay A.; Mayers, Charles J.; Michel, Robert L.

    2013-01-01

    We develop a general equation for converting laboratory-reported tritium levels, expressed either as concentrations (tritium isotope number fractions) or mass-based specific activities, to mass fractions in aqueous systems. Assuming that all tritium is in the form of monotritiated water simplifies the derivation and is shown to be reasonable for most environmental settings encountered in practice. The general equation is nonlinear. For tritium concentrations c less than 4.5×1012 tritium units (TU) - i.e. specific tritium activities11 Bq kg-1 - the mass fraction w of tritiated water is approximated to within 1 part per million by w ≈ c×2.22293×10-18, i.e. the conversion is linear for all practical purposes. Terrestrial abundances serve as a proxy for non-tritium isotopes in the absence of sample-specific data. Variation in the relative abundances of non-tritium isotopes in the terrestrial hydrosphere produces a minimum range for the mantissa of the conversion factor of [2.22287; 2.22300].

  7. 2017 Status report-Tritium aging studies on stainless steel: Effect of hydrogen, tritium and decay helium on the fracture-toughness properties of stem, cup and block forgings

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

    Morgan, Michael J.

    The materials of construction of tritium reservoirs are forged stainless steels. During service, the structural properties of the stainless steel change over time because of the diffusion of tritium into the reservoir wall and its radioactive decay to helium-3. This aging effect can cause cracks to initiate and grow which could result in a tritium leak or delayed failure of a tritium reservoir. Numerous factors affect the tendency for crack formation and propagation and are being investigated in this program. The goal of the research is to provide relevant fracture mechanics data that can be used by the design agenciesmore » in their assessments of tritium reservoir structural integrity. In this status report, new experimental results are presented on the effects of tritium and decay helium on the cracking properties of specimens taken from actual tritium reservoir forgings instead of the experimental forgings of past programs. The properties measured are more representative of actual reservoir properties because the microstructure of the specimens tested are more like that of the actual tritium reservoirs. The program was designed to measure the effects of material variables on tritium compatibility and includes two stainless steels (Type 304L and 316L stainless steel), multiple yield strengths (360-500 MPa), and multiple forging shapes (Stem, Cup, and Block).« less

  8. Tritium safety study using Caisson Assembly (CATS) at TPL/JAEA

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

    Hayashi, T.; Kobayashi, K.; Iwai, Y.

    Tritium confinement is required as the most important safety Junction for a fusion reactor. In order to demonstrate the confinement performance experimentally, an unique equipment, called CATS: Caisson Assembly for Tritium Safety study, was installed in Tritium Process Laboratory of Japan Atomic Energy Agency and operated for about 10 years. Tritium confinement and migration data in CATS have been accumulated and dynamic simulation code was accumulated using these data. Contamination and decontamination behavior on various materials and new safety equipment functions have been investigated under collaborations with a lot of laboratories and universities. (authors)

  9. Small system for tritium accelerator mass spectrometry

    DOEpatents

    Roberts, M.L.; Davis, J.C.

    1993-02-23

    Apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample is disclosed. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radio-frequency quadrupole accelerator is directly coupled to and axially aligned with the source at an angle of substantially zero degrees. The accelerator accelerates species of the sample having different mass to different energy levels along the same axis as the ion beam. A spectrometer is used to detect the concentration of tritium ions in the sample. In one form of the invention, an energy loss spectrometer is used which includes a foil to block the passage of hydrogen, deuterium and [sup 3]He ions, and a surface barrier or scintillation detector to detect the concentration of tritium ions. In another form of the invention, a combined momentum/energy loss spectrometer is used which includes a magnet to separate the ion beams, with Faraday cups to measure the hydrogen and deuterium and a surface barrier or scintillation detector for the tritium ions.

  10. Small system for tritium accelerator mass spectrometry

    DOEpatents

    Roberts, Mark L.; Davis, Jay C.

    1993-01-01

    Apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample is disclosed. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radio-frequency quadrupole accelerator is directly coupled to and axially aligned with the source at an angle of substantially zero degrees. The accelerator accelerates species of the sample having different mass to different energy levels along the same axis as the ion beam. A spectrometer is used to detect the concentration of tritium ions in the sample. In one form of the invention, an energy loss spectrometer is used which includes a foil to block the passage of hydrogen, deuterium and .sup.3 He ions, and a surface barrier or scintillation detector to detect the concentration of tritium ions. In another form of the invention, a combined momentum/energy loss spectrometer is used which includes a magnet to separate the ion beams, with Faraday cups to measure the hydrogen and deuterium and a surface barrier or scintillation detector for the tritium ions.

  11. Health risk assessment of potable water containing small amount of tritium oxide

    NASA Astrophysics Data System (ADS)

    Momot, O. A.; Synzynys, B. I.; Oudalova, A. A.

    2017-01-01

    The problem of groundwater pollution with tritium in a vicinity of radiation-dangerous facilities in Obninsk is considered. The information on the specific activity of tritium in Obninsk water sources is provided. The formula for the calculation of the β-radiation absorbed dose from tritium ingestion is proposed, reflecting the biological behavior of tritium in a human body. To establish the extent of tritium effects on human, the health risk is assessed. It is shown that if the specific activity of tritium in drinking water amounts to 10 Bq/l, the risk of stochastic effects of radiation will not exceed the limit of the individual lifetime risk.

  12. An OKQPSK modem incorporating numerically controlled carrier synthesis

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

    Oetken, R.E.

    1988-04-04

    The feasibility of incorporating numerically controlled oscillators (NCO) in communication related applications is evaluated. NCO generation of sinusoids may prove useful in systems requiring precise frequency control, tuning linearity, and orthogonality versus frequency. An OKQPSK modem operating at a data rate of 200 kb/s was fabricated. The modem operates in a back to back hardwired channel and thus does not incorporate carrier or symbol timing recovery. Spectra of the NCO generated sinusoids are presented along with waveforms from the modulation and demodulation process. Generation of sinusoids in the digital domain is a viable alternative to analog oscillators. Implementation of anmore » NCO should be considered when frequency allocation, tuning bandwidth, or frequency hopped transmission requires precise frequency synthesis. 24 figs.« less

  13. Advancement Of Tritium Powered Betavoltaic Battery Systems FY16 EOY Report

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

    Staack, G.; Gaillard, J.; Hitchcock, D.

    2016-10-12

    The goal of this work is to increase the power output of tritium-powered betavoltaic batteries and investigate the change in power output and film resistance in real-time during tritium loading of adsorbent films. To this end, several tritium-compatible test vessels with the capability of measuring both the resistivity of a tritium trapping film and the power output of a betavoltaic device in-situ have been designed and fabricated using four electrically insulated feedthroughs in tritium-compatible load cells. Energy conversion devices were received from Widetronix, a betavoltaic manufacturing firm based in Ithaca, NY. Thin films were deposited on the devices and cappedmore » with palladium to facilitate hydrogen loading. Gold contacts were then deposited on top of the films to allow resistivity measurements of the film during hydrogen loading. Finally, the chips were wire bonded and installed in the test cells. The cells were then baked-out under vacuum and leak checked at temperature to reduce the chances of tritium leaks during loading. Following the bake-out, IV curves were measured to verify no internal wires were compromised, and the cells were delivered to Tritium for loading. Tritium loading is anticipated in October, 2017.« less

  14. Tritium in the western Mediterranean Sea during 1981 Phycemed cruise

    NASA Astrophysics Data System (ADS)

    Andrie, Chantal; Merlivat, Liliane

    1988-02-01

    We report on simultaneous hydrological and tritium data taken in the western Mediterranean Sea during April 1981 and which implement our knowledge of the spatial and temporal variability of the convection process occurring in the Northern Basin (Gulf of Lion, Ligurian Sea). The renewal time of the deep waters in the Medoc area is calculated to be 11 ± 2 years using a box-model assymption. An important local phenomenon of "cascading" off the Ebro River near the Spanish coast is, noticeable by the use of tritium data. In the Sardinia Straits area tritium data indicate very active mixing between 100 and 500 m depth. The tritium subsurface maxima in Sardinia Straits suggests the influence of not only the Levantine Intermediate Water (LIW) but also an important shallower component. In waters deeper than 500m, an active mixing occurs between the deep water and the LIW via an intermediate water mass from the Tyrrhenian Sea by "salt-fingering". Assuming a two end-member mixing. We determine the deep tritium content in the Sardinia Channel to be 1.8 TU. For comparison, the deep tritium content of the Northern Basin is equal to 1.3 TU. Tritium data relative to the Alboran Sea show that a layer of high tritium content persists all along its path from Sardifia to Gibraltar on a density surface shallower than the intermediate water. The homogeneity of the deep tritium concentrations between 1200 m depth and the bottom corroborate the upward "pumping" and westward circulation of deep waters along the continental slope of the North African Shelf. From the data measured in the Sardinia Straits and in the Alboran Sea, and upper limit of the deep advection rate of the order of 0.5 cm s-1 is estimated.

  15. Tritium permeation through austenitic stainless steel with chemically densified coating as a tritium permeation barrier

    NASA Astrophysics Data System (ADS)

    Terai, Takayuki; Yoneoka, Toshiaki; Tanaka, Hirohisa; Kawamura, Hiroshi; Nakamichi, Masaru; Miyajima, Kiyoshi

    1994-09-01

    Chemically densified coating formed on the surface of austenitic stainless steel (SUS 316) was examined for compatibility with molten lithium-lead eutectic alloy (Li17Pb83) and tritium permeability. The chemically densified coating (CDC) consisting of SiO 2 particles and a Cr 2O 3 matrix with a thickness of 60 μm was unstable in contact with the molten alloy as predicted from a thermodynamic calculation at 600°C, and it was degraded in several days. In an in-pile experiment, specimens with the coating on the front surface or the rear surface were immersed in Li17Pb83 molten alloy, and their tritium permeabilities were measured. The permeability of the former was reduced to {1}/{10} of the ideal value in the diffusion-limited case, while that of the latter was less than {1}/{100} of the diffusion-limited value even in a pure H 2 atmosphere. It is concluded that CDC is quite effective to reduce tritium permeability in the condition of not contacting molten Li17Pb83 alloy.

  16. VAPOR PRESSURE ISOTOPE EFFECTS IN THE MEASUREMENT OF ENVIRONMENTAL TRITIUM SAMPLES.

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

    Kuhne, W.

    2012-12-03

    Standard procedures for the measurement of tritium in water samples often require distillation of an appropriate sample aliquot. This distillation process may result in a fractionation of tritiated water and regular light water due to the vapor pressure isotope effect, introducing either a bias or an additional contribution to the total tritium measurement uncertainty. The magnitude of the vapor pressure isotope effect is characterized as functions of the amount of water distilled from the sample aliquot and the heat settings for the distillation process. The tritium concentration in the distillate is higher than the tritium concentration in the sample earlymore » in the distillation process, it then sharply decreases due to the vapor pressure isotope effect and becomes lower than the tritium concentration in the sample, until the high tritium concentration retained in the boiling flask is evaporated at the end of the process. At that time, the tritium concentration in the distillate again overestimates the sample tritium concentration. The vapor pressure isotope effect is more pronounced the slower the evaporation and distillation process is conducted; a lower heat setting during the evaporation of the sample results in a larger bias in the tritium measurement. The experimental setup used and the fact that the current study allowed for an investigation of the relative change in vapor pressure isotope effect in the course of the distillation process distinguish it from and extend previously published measurements. The separation factor as a quantitative measure of the vapor pressure isotope effect is found to assume values of 1.034 {+-} 0.033, 1.052 {+-} 0.025, and 1.066 {+-} 0.037, depending on the vigor of the boiling process during distillation of the sample. A lower heat setting in the experimental setup, and therefore a less vigorous boiling process, results in a larger value for the separation factor. For a tritium measurement in water samples, this implies

  17. Glovebox stripper system tritium capture efficiency-literature review

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

    James, D. W.; Poore, A. S.

    2015-09-28

    Glovebox Stripper Systems (GBSS) are intended to minimize tritium emissions from glovebox confinement systems in Tritium facilities. A question was raised to determine if an assumed 99% stripping (decontamination) efficiency in the design of a GBBS was appropriate. A literature review showed the stated 99% tritium capture efficiency used for design of the GBSS is reasonable. Four scenarios were indicated for GBSSs. These include release with a single or dual stage setup which utilizes either single-pass or recirculation for stripping purposes. Examples of single-pass as well as recirculation stripper systems are presented and reviewed in this document.

  18. Dismantling of the PETRA glove box: tritium contamination and inventory assessment

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

    Wagner, R.

    2015-03-15

    The PETRA facility is the first installation in which experiments with tritium were carried out at the Tritium Laboratory Karlsruhe. After completion of two main experimental programs, the decommissioning of PETRA was initiated with the aim to reuse the glove box and its main still valuable components. A decommissioning plan was engaged to: -) identify the source of tritium release in the glove box, -) clarify the status of the main components, -) assess residual tritium inventories, and -) de-tritiate the components to be disposed of as waste. Several analytical techniques - calorimetry on small solid samples, wipe test followedmore » by liquid scintillation counting for surface contamination assessment, gas chromatography on gaseous samples - were deployed and cross-checked to assess the remaining tritium inventories and initiate the decommissioning process. The methodology and the main outcomes of the numerous different tritium measurements are presented and discussed. (authors)« less

  19. A study of tritium in municipal solid waste leachate and gas

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

    Mutch Jr, R. D.; Manhattan College, Riverdale, NY; Columbia Univ., New York, NY

    2008-07-15

    It has become increasingly clear in the last few years that the vast majority of municipal solid waste landfills produce leachate that contains elevated levels of tritium. The authors recently conducted a study of landfills in New York and New Jersey and found that the mean concentration of tritium in the leachate from ten municipal solid waste (MSW) landfills was 33,800 pCi/L with a peak value of 192,000 pCi/L. A 2003 study in California reported a mean tritium concentration of 99,000 pCi/L with a peak value of 304,000 pCi/L. Studies in Pennsylvania and the UK produced similar results. The USEPAmore » MCL for tritium is 20,000 pCi/L. Tritium is also manifesting itself as landfill gas and landfill gas condensate. Landfill gas condensate samples from landfills in the UK and California were found to have tritium concentrations as high as 54,400 and 513,000 pCi/L, respectively. The tritium found in MSW leachate is believed to derive principally from gaseous tritium lighting devices used in some emergency exit signs, compasses, watches, and even novelty items, such as 'glow stick' key chains. This study reports the findings of recent surveys of leachate from a number of municipal solid waste landfills, both open and closed, from throughout the United States and Europe. The study evaluates the human health and ecological risks posed by elevated tritium levels in municipal solid waste leachate and landfill gas and the implications to their safe management. We also assess the potential risks posed to solid waste management facility workers exposed to tritium-containing waste materials in transfer stations and other solid waste management facilities. (authors)« less

  20. Tritium Effects on Fracture Toughness of Stainless Steel Weldments

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

    MORGAN, MICHAEL; CHAPMAN, G. K.; TOSTEN, M. H.

    2005-05-12

    The effects of tritium on the fracture toughness properties of Type 304L and Type 21-6-9 stainless steel weldments were measured. Weldments were tritium-charged-and-aged and then tested in order to measure the effect of the increasing decay helium content on toughness. The results were compared to uncharged and hydrogen-charged samples. For unexposed weldments having 8-12 volume percent retained delta ferrite, fracture toughness was higher than base metal toughness. At higher levels of weld ferrite, the fracture toughness decreased to values below that of the base metal. Hydrogen-charged and tritium-charged weldments had lower toughness values than similarly charged base metals and toughnessmore » decreased further with increasing weld ferrite content. The effect of decay helium content was inconclusive because of tritium off-gassing losses during handling, storage and testing. Fracture modes were dominated by the dimpled rupture process in unexposed weldments. In hydrogen and tritium-exposed weldments, the fracture modes depended on the weld ferrite content. At high ferrite contents, hydrogen-induced transgranular fracture of the weld ferrite phase was observed.« less

  1. Observation of tritium in gas/plasma loaded titanium samples

    NASA Astrophysics Data System (ADS)

    Srinivasan, M.; Shyam, A.; Kaushik, T. C.; Rout, R. K.; Kulkarni, L. V.; Krishnan, M. S.; Malhotra, S. K.; Nagvenkar, V. G.; Iyengar, P. K.

    1991-05-01

    The observation of significant neutron yield from gas loaded titanium samples at Frascati in April 1989 opened up an alternate pathway to the investigation of anomalous nuclear phenomena in deuterium/solid systems, complimenting the electrolytic approach. Since then at least six different groups have successfully measured burst neutron emission from deuterated titanium shavings following the Frascati methodology, the special feature of which was the use of liquid nitrogen to create repeated thermal cycles resulting in the production of non-equilibrium conditions in the deuterated samples. At Trombay several variations of the gas loading procedure have been investigated including induction heating of single machined titanium targets in a glass chamber as well as use of a plasma focus device for deuteriding its central titanium electrode. Stemming from earlier observations both at BARC and elsewhere that tritium yield is ≂108 times higher than neutron output in cold fusion experiments, we have channelised our efforts to the search for tritium rather than neutrons. The presence of tritium in a variety gas/plasma loaded titanium samples has been established successfully through a direct measurement of the radiations emitted as a result of tritium decay, in contradistinction to other groups who have looked for tritium in the extracted gases. In some samples we have thus observed tritium levels of over 10 MBq with a corresponding (t/d) ratio of ≳10-5.

  2. Tritium saturation in plasma-facing materials surfaces1

    NASA Astrophysics Data System (ADS)

    Longhurst, Glen R.; Anderl, Robert A.; Causey, Rion A.; Federici, Gianfranco; Haasz, Anthony A.; Pawelko, Robert J.

    1998-10-01

    Plasma-facing components in the International Thermonuclear Experimental Reactor (ITER) will experience high heat loads and intense plasma fluxes of order 10 20-10 23 particles/m 2s. Experiments on Be and W, two of the materials considered for use in ITER, have revealed that a tritium saturation phenomenon can take place under these conditions in which damage to the surface results that enhances the return of implanted tritium to the plasma and inhibits uptake of tritium. This phenomenon is important because it implies that tritium inventories due to implantation in these plasma-facing materials will probably be lower than was previously estimated using classical recombination-limited release at the plasma surface. Similarly, permeation through these components to the coolant streams should be reduced. In this paper we discuss evidences for the existence of this phenomenon, describe techniques for modeling it, and present results of the application of such modeling to prior experiments.

  3. Analysis of air mass trajectories to explain observed variability of tritium in precipitation at the Southern Sierra Critical Zone Observatory, California, USA

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

    Visser, Ate; Thaw, Melissa; Esser, Brad

    Understanding the behavior of tritium, a radioactive isotope of hydrogen, in the environment is important to evaluate the exposure risk of anthropogenic releases, and for its application as a tracer in hydrology and oceanography. To understand and predict the variability of tritium in precipitation, HYSPLIT air mass trajectories were analyzed for 16 aggregate precipitation samples collected over a 2 year period at irregular intervals at a research site located at 2000 m elevation in the southern Sierra Nevada (California, USA). Attributing the variation in tritium to specific source areas confirms the hypothesis that higher latitude or inland sources bring highermore » tritium levels in precipitation than precipitation originating in the lower latitude Pacific Ocean. In this case, the source of precipitation accounts for 79% of the variation observed in tritium concentrations. In conclusion, air mass trajectory analysis is a promising tool to improve the predictions of tritium in precipitation at unmonitored locations and thoroughly understand the processes controlling transport of tritium in the environment.« less

  4. Analysis of air mass trajectories to explain observed variability of tritium in precipitation at the Southern Sierra Critical Zone Observatory, California, USA

    DOE PAGES

    Visser, Ate; Thaw, Melissa; Esser, Brad

    2017-11-20

    Understanding the behavior of tritium, a radioactive isotope of hydrogen, in the environment is important to evaluate the exposure risk of anthropogenic releases, and for its application as a tracer in hydrology and oceanography. To understand and predict the variability of tritium in precipitation, HYSPLIT air mass trajectories were analyzed for 16 aggregate precipitation samples collected over a 2 year period at irregular intervals at a research site located at 2000 m elevation in the southern Sierra Nevada (California, USA). Attributing the variation in tritium to specific source areas confirms the hypothesis that higher latitude or inland sources bring highermore » tritium levels in precipitation than precipitation originating in the lower latitude Pacific Ocean. In this case, the source of precipitation accounts for 79% of the variation observed in tritium concentrations. In conclusion, air mass trajectory analysis is a promising tool to improve the predictions of tritium in precipitation at unmonitored locations and thoroughly understand the processes controlling transport of tritium in the environment.« less

  5. Assessment of tritium in the Savannah River Site environment

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

    Carlton, W.H.; Murphy, C.E. Jr.; Bauer, L.R.

    1993-10-01

    This report is the first revision to a series of reports on radionuclides inn the SRS environment. Tritium was chosen as the first radionuclide in the series because the calculations used to assess the dose to the offsite population from SRS releases indicate that the dose due to tritium, through of small consequence, is one of the most important the radionuclides. This was recognized early in the site operation, and extensive measurements of tritium in the atmosphere, surface water, and ground water exist due to the effort of the Environmental Monitoring Section. In addition, research into the transport and fatemore » of tritium in the environment has been supported at the SRS by both the local Department of Energy (DOE) Office and DOE`s Office of Health and Environmental Research.« less

  6. Project 8: Towards cyclotron radiation emission spectroscopy on tritium

    NASA Astrophysics Data System (ADS)

    Fertl, Martin; Project 8 Collaboration

    2017-01-01

    Project 8 aims to determine the neutrino mass by making a precise measurement of the beta decay of molecular tritium (Q = 18.6 keV) using the recently demonstrated the technique of cyclotron radiation emission spectroscopy (CRES). We report on results for calibration measurements performed with Kr-83m in a gas cell that fulfills the stringent requirements for a measurement using tritium: cryogenic operation, safe tritium handling, a non-magnetic design, and a good microwave guide performance. The phased program that allows Project 8 to probe the neutrino mass range accessible using molecular tritium is described. Major financial support by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics to the University of Washington under Award Number DE-FG02-97ER41020 is acknowledged

  7. Power-scaling performance of a three-dimensional tritium betavoltaic diode

    NASA Astrophysics Data System (ADS)

    Liu, Baojun; Chen, Kevin P.; Kherani, Nazir P.; Zukotynski, Stefan

    2009-12-01

    Three-dimensional diodes fabricated by electrochemical etching are exposed to tritium gas at pressures from 0.05 to 33 atm at room temperature to examine its power scaling performance. It is shown that the three-dimensional microporous structure overcomes the self-absorption limited saturation of beta flux at high tritium pressures. These results are contrasted against the three-dimensional device powered in one instance by tritium absorbed in the near surface region of the three-dimensional microporous network, and in another by a planar scandium tritide foil. These findings suggest that direct tritium occlusion in the near surface of three-dimensional diode can improve the specific power production.

  8. Recent Upgrades at the Safety and Tritium Applied Research Facility

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

    Cadwallader, Lee Charles; Merrill, Brad Johnson; Stewart, Dean Andrew

    This paper gives a brief overview of the Safety and Tritium Applied Research (STAR) facility operated by the Fusion Safety Program (FSP) at the Idaho National Laboratory (INL). FSP researchers use the STAR facility to carry out experiments in tritium permeation and retention in various fusion materials, including wall armor tile materials. FSP researchers also perform other experimentation as well to support safety assessment in fusion development. This lab, in its present two-building configuration, has been in operation for over ten years. The main experiments at STAR are briefly described. This paper discusses recent work to enhance personnel safety atmore » the facility. The STAR facility is a Department of Energy less than hazard category 3 facility; the personnel safety approach calls for ventilation and tritium monitoring for radiation protection. The tritium areas of STAR have about 4 to 12 air changes per hour, with air flow being once through and then routed to the facility vent stack. Additional radiation monitoring has been installed to read the laboratory room air where experiments with tritium are conducted. These ion chambers and bubblers are used to verify that no significant tritium concentrations are present in the experiment rooms. Standby electrical power has been added to the facility exhaust blower so that proper ventilation will now operate during commercial power outages as well as the real-time tritium air monitors.« less

  9. Optofluidics incorporating actively controlled micro- and nano-particles

    PubMed Central

    Kayani, Aminuddin A.; Khoshmanesh, Khashayar; Ward, Stephanie A.; Mitchell, Arnan; Kalantar-zadeh, Kourosh

    2012-01-01

    The advent of optofluidic systems incorporating suspended particles has resulted in the emergence of novel applications. Such systems operate based on the fact that suspended particles can be manipulated using well-appointed active forces, and their motions, locations and local concentrations can be controlled. These forces can be exerted on both individual and clusters of particles. Having the capability to manipulate suspended particles gives users the ability for tuning the physical and, to some extent, the chemical properties of the suspension media, which addresses the needs of various advanced optofluidic systems. Additionally, the incorporation of particles results in the realization of novel optofluidic solutions used for creating optical components and sensing platforms. In this review, we present different types of active forces that are used for particle manipulations and the resulting optofluidic systems incorporating them. These systems include optical components, optofluidic detection and analysis platforms, plasmonics and Raman systems, thermal and energy related systems, and platforms specifically incorporating biological particles. We conclude the review with a discussion of future perspectives, which are expected to further advance this rapidly growing field. PMID:23864925

  10. Tritium Records to Trace Stratospheric Moisture Inputs in Antarctica

    NASA Astrophysics Data System (ADS)

    Fourré, E.; Landais, A.; Cauquoin, A.; Jean-Baptiste, P.; Lipenkov, V.; Petit, J.-R.

    2018-03-01

    Better assessing the dynamic of stratosphere-troposphere exchange is a key point to improve our understanding of the climate dynamic in the East Antarctica Plateau, a region where stratospheric inputs are expected to be important. Although tritium (3H or T), a nuclide naturally produced mainly in the stratosphere and rapidly entering the water cycle as HTO, seems a first-rate tracer to study these processes, tritium data are very sparse in this region. We present the first high-resolution measurements of tritium concentration over the last 50 years in three snow pits drilled at the Vostok station. Natural variability of the tritium records reveals two prominent frequencies, one at about 10 years (to be related to the solar Schwabe cycles) and the other one at a shorter periodicity: despite dating uncertainty at this short scale, a good correlation is observed between 3H and Na+ and an anticorrelation between 3H and δ18O measured on an individual pit. The outputs from the LMDZ Atmospheric General Circulation Model including stable water isotopes and tritium show the same 3H-δ18O anticorrelation and allow further investigation on the associated mechanism. At the interannual scale, the modeled 3H variability matches well with the Southern Annular Mode index. At the seasonal scale, we show that modeled stratospheric tritium inputs in the troposphere are favored in winter cold and dry conditions.

  11. Effectiveness of passivation techniques on hydrogen desorption in a tritium environment

    NASA Astrophysics Data System (ADS)

    Woodall, Steven Michael

    2009-11-01

    Tritium is a radioactive isotope of hydrogen. It is used as a fuel in fusion reactors, a booster material in nuclear weapons and as a light source in commercial applications. When tritium is used in fusion reactors, and especially when used in the manufacture of nuclear weapons, purity is critical. For U.S. Department of Energy use, tritium is recycled by Savannah River Site in South Carolina and is processed to a minimum purity of 99.5%. For use elsewhere in the country, it must be shipped and stored, while maintaining the highest purity possible. As an isotope of hydrogen it exchanges easily with the most common isotope of hydrogen, protium. Stainless steel bottles are used to transport and store tritium. Protium, present in air, becomes associated in and on the surface of stainless steel during and after the manufacture of the steel. When filled, the tritium within the bottle exchanges with the protium in and on the surface of the stainless steel, slowly contaminating the pure tritium with protium. The stainless steel is therefore passivated to minimize the protium outgrowth of the bottles into the pure tritium. This research is to determine how effective different passivation techniques are in minimizing the contamination of tritium with protium. Additionally, this research will attempt to determine a relationship between surface chemistry of passivated steels and protium contamination of tritium. The conclusions of this research found that passivated bottles by two companies which routinely provide passivated materials to the US Department of Energy provide low levels of protium outgrowth into pure tritium. A bottle passivated with a material to prevent excessive corrosion in a highly corrosive environment, and a clean and polished bottle provided outgrowth rates roughly twice those of the passivated bottles above. Beyond generally high levels of chromium, oxygen, iron and nickel in the passivated bottles, there did not appear to be a strong correlation

  12. Experiments with high-voltage insulators in the presence of tritium

    NASA Astrophysics Data System (ADS)

    Grisham, L. R.; Falter, H.; Causey, R.; Chrisman, W.; Stevenson, T.; Wright, K.

    1991-02-01

    During the final deuterium-tritium phases of the TFTR and JET tokamaks half of the neutral injectors will be used to produce tritium neutral beams to maintain an equal mix of deuterium and tritium in the core plasma, and such requirements may also occur in future devices. This will require that the voltage hold off capabilities of the high voltage insulators in the accelerators be unimpaired by any charge buildups associated with the beta decay of adsorbed layers. We report tests in which we measured the drain currents under high dc voltage of TFTR and JET accelerator insulators while they were successively exposed to vacuum, deuterium and tritium. There did not appear to be any substantial reduction in hold-off capability with tritium, although at some voltages there was a small increase in the leakage current. We also compared the breakdown properties of a plastic tubing filled with deuterium and then tritium at varying pressures, since such tubing has been considered as a high-voltage break in the gas feed system for TFTR, and the presence of large numbers of electron-ion pairs might lead to enhanced Paschen breakdown. We found no significant differences in the behavior for the geometry used.

  13. Recovery of Retained Tritium from Graphite Tile of JT-60U

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

    Takeishi, Toshiharu; Katayama, Kazunari; Nishikawa, Masabumi

    Tritium thermal release and full combustion with oxygen were performed on isotropic graphite tiles used for plasma facing material of JT-60U. Approximately 50-80 % of tritium was released by dry argon gas purge and 20-50 % of tritium was released by humid argon gas purge up to 800-1200 deg. C within one day, respectively. Further several percent of tritium was released by full combustion with oxygen. It was experimentally confirmed that all retained tritium is not released by thermal dry gas purge and by use of isotope exchange reaction at high temperature in such a short period. In the fullmore » combustion operation, isotropic graphite begins to combust at higher temperature than 650 deg. C, but effective combustion temperature was higher than 700 deg. C. Since it is very difficult to heat the graphite tile attached on the wall of vacuum vessel at higher than 700 deg. C, it is considered to be not easy to recover all the tritium retained in the graphite while in the vacuum vessel.« less

  14. An investigation of tritium transfer in reactor loops

    NASA Astrophysics Data System (ADS)

    Ilyasova, O. H.; Mosunova, N. A.

    2017-09-01

    The work is devoted to the important task of the numerical simulation and analysis of the tritium behaviour in the reactor loops. The simulation was carried out by HYDRA-IBRAE/LM code, which is being developed in Nuclear safety institute of the Russian Academy of Sciences. The code is intended for modeling of the liquid metal flow (sodium, lead and lead-bismuth) on the base of non-homogeneous and non-equilibrium two-fluid model. In order to simulate tritium transfer in the code, the special module has been developed. Module includes the models describing the main phenomena of tritium behaviour in reactor loops: transfer, permeation, leakage, etc. Because of shortage of the experimental data, a lot of analytical tests and comparative calculations were considered. Some of them are presented in this work. The comparison of estimation results and experimental and analytical data demonstrate not only qualitative but also good quantitative agreement. It is possible to confirm that HYDRA-IBRAE/LM code allows modeling tritium transfer in reactor loops.

  15. Advancement Of Tritium Powered Betavoltaic Battery Systems

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

    Staack, G.; Gaillard, J.; Hitchcock, D.

    2015-10-14

    Due to their decades-long service life and reliable power output under extreme conditions, betavoltaic batteries offer distinct advantages over traditional chemical batteries, especially in applications where frequent battery replacement is hazardous, or cost prohibitive. Although many beta emitting isotopes exist, tritium is considered ideal in betavoltaic applications for several reasons: 1) it is a “pure” beta emitter, 2) the beta is not energetic enough to damage the semiconductor, 3) it has a moderately long half-life, and 4) it is readily available. Unfortunately, the widespread application of tritium powered betavoltaics is limited, in part, by their low power output. This researchmore » targets improving the power output of betavoltaics by increasing the flux of beta particles to the energy conversion device (the p-n junction) through the use of low Z nanostructured tritium trapping materials.« less

  16. Design and tritium permeation analysis of China HCCB TBM port cell

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

    Jiangfeng, S.; Guoqiang, H.; Zhiyong, H.

    2015-03-15

    China is planning to develop a helium-cooled ceramic breeder (HCCB) test blanket module (TBM) on ITER to test key blanket technologies. In this paper, the design and tritium permeation analysis of China HCCB TBM port cell are introduced. A theoretical model has been developed to estimate tritium permeation rates and leak rates from the components and pipes which China has scheduled to house in the port cell. It is shown that on normal working conditions, the permeation and leak rate of the systems in the port cell will be no higher than 1.58 Ci/d without the use of tritium permeationmore » barriers, and 0.10 Ci/d with the use of tritium permeation barriers. It also appears that tritium permeation barriers are necessary for high temperature components such as the reduction bed and the heater.« less

  17. Tritium behavior pattern in some soil-plant systems in a tropical environment

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

    Soma, S.D.; Iyengar, T.S.; Sadarangani, S.H.

    1975-01-01

    A study of the distribution pattern of tritium in the soil/plant environment gives a valuable ecological information on the natural water balance. The results of such a study for the conditions obtaining in India are given in this paper. Field studies are carried out by injection of tritium into some soil/ plant systems and following the transfer pathways. The method of extraction for tissue-free-water-tritium (TFWT) is based on the vacuum freeze-drying technique while the tissue-bound-tritium (TBT) is estimated by a modified version of the Shoniger method. The determination of residence time of tritium in aqueous and organic phase in amore » number of tropical trees has been carried out both for stem- injection as well as intake from the soil. From the results of this study the tree biomass and transpiration rates have been determined. The tritium profile over time, for an acute exposure in certain trees such as Morinda Tinetoria, Achras Sapota etc. shows significantly different patterns compared to the normal pattern shown by Mangifera Indica, Terminalia Catappa, Ficus Glomerata etc. The period of investigation in each case varied from 400 to 1000 h. In most of the cases, the TBT fractions were very low compared to TFWT fractions in the initial stages. The tritium behaviour in the tree reflects significant characteristics of the tritium behaviour in the soil system. The authors have found that the leaf sampling can be used as an indicator of total environmental tritium behaviour. (auth)« less

  18. Tritium recapture behavior at a nuclear power reactor due to airborne releases.

    PubMed

    Harris, Jason T; Miller, David W; Foster, Doug W

    2008-08-01

    This paper describes the initiatives taken by Cook Nuclear Plant to study the on-site behavior of recaptured tritium released in its airborne effluents. Recapture is the process where a released radioactive effluent, in this case tritium, is brought back on-site through some mechanism. Precipitation, shifts in wind direction, or anthropogenic structures that restrict or alter effluent movement can all lead to recapture. The investigation was started after tritium was detected in the north storm drain outfall. Recent inadvertent tritium releases by several other nuclear power plants, many of which entered the groundwater, have led to increased surveillance and scrutiny by regulatory authorities and the general public. To determine the source of tritium in the outfall, an on-site surface water, well water, rainwater and air-conditioning condensate monitoring program was begun. Washout coefficients were also determined to compare with results reported by other nuclear power plants. Program monitoring revealed detectable tritium concentrations in several precipitation sample locations downwind of the two monitored containment building release vents. Tritium was found in higher concentrations in air-conditioning condensate, with a mean value of 528 Bq L(-1) (14,300 pCi L(-1)). The condensate, and to a lesser extent rainwater, were contributing to the tritium found in the north storm drain outfall. Maximum concentration values for each sample type were used to estimate the most conservative dose. A maximum dose of 1.1 x 10(-10) mSv (1.1 x 10(-8) mrem) total body was calculated to determine the health impact of the tritium detected.

  19. Tritium-field betacells

    NASA Astrophysics Data System (ADS)

    Walko, R. J.; Lincoln, R. C.; Baca, W. E.; Goods, S. H.; Negley, G. H.

    Betavoltaic power sources operate by converting the nuclear decay energy of beta-emitting radioisotopes into electricity. Since they are not chemically driven, they could operate at temperatures which would either be too hot or too cold for typical chemical batteries. Further, for long lived isotopes, they offer the possibility of multi-decade active lifetimes. Two approaches are being investigated: direct and indirect conversion. Direct conversion cells consist of semiconductor diodes similar to photovoltaic cells. Beta particle directly bombard these cells, generating electron-hole pairs in the semiconductor which are converted to useful power. When using low power flux beta emitters, wide bandgap semiconductors are required to achieve useful conversion efficiencies. The combination of tritium, as the beta emitter, and gallium phosphide (GaP), as the semiconductor converter, was evaluated. Indirect conversion betacells first convert the beta energy to light with a phosphor, and then to electricity with photovoltaic cells. An indirect conversion power source using a tritium radioluminescent (RL) light is being investigated. Our analysis indicates that this approach has the potential for significant volume and cost savings over the direct conversion method.

  20. Tritium volume activity in the Baltic Sea in 1987-1989

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

    Styro, D.B.; Korotkov, V.P.

    Tritium volume activities measured in the Baltic Sea are summarized in this paper. Activity levels were determined by the liquid scintillation method with a LS-1000 counter. The field investigations showed that the tritium volume activity in the Baltic Sea can change substantially in absolute magnitude. Therefore, average volume activity is used as an indicator of natural content. Correlations between calculated (averaged) tritium activity levels and the Chernobyl accident are very briefly discussed. 7 refs., 2 figs., 1 tab.

  1. Tritium and tritons in cold fusion

    NASA Astrophysics Data System (ADS)

    Wolf, K. L.; Whitesell, L.; Jabs, H.; Shoemaker, J.

    1991-05-01

    An analysis is conducted on reports of tritium production and of charged-particle emission from deuterated palladium and titanium. Possible sources of error are outline and the lack of definitive experiments is discussed. Extensive sets of experiments are reported in which two previously reported results are checked in detail. A search for charged-particle emission was conducted on deuterated titanium and 6-6-2 titanium alloy that was subjected to cryogenic cycling. Two delta E-E silicon telescopes were used to count 42 samples for 3-4 cycles each from 84K to room temperature. No charge-one particles were detected and alpha particle yields of a few counters per day corresponded to background levels. A search for tritium production from 1 mm diameter palladium wire was conducted on 130 electrolytic cells in D2O and H2O, and in 250 metal samples. Several samples associated with one lot of palladium stock showed latent tritium levels well above background. No evidence was obtained for the occurrence of nuclear reactions in the electrolytic cells.

  2. Dependence of Tritium Release from Stainless Steel on Temperature and Water Vapor

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

    Shmayda, W. T.; Sharpe, M.; Boyce, A. M.

    The impact of water vapor and temperature on the release of tritium from stainless steel was studied. Degreased stainless steel samples loaded with tritium at room temperature following a 24-h degassing in vacuum at room temperature were subjected to increasing temperatures or humidity. In general, increasing either the sample temperature or the humidity causes an increased quantity of tritium to be removed. Increasing the temperature to 300°C in a dry gas stream results in a significant release of tritium and is therefore an effective means for reducing the tritium inventory in steel. For humid purges at 30°C, a sixfold increasemore » in humidity results in a tenfold increase in the peak outgassing rate. Increasing the humidity from 4 parts per million (ppm) to 1000 ppm when the sample temperature is 100°C causes a significant increase in the tritium outgassing rate. Finally, a simple calculation shows that only 15% of the activity present in the sample was removed in these experiments, suggesting that the surface layer of adsorbed water participates in regulating tritium desorption from the surface.« less

  3. Dependence of Tritium Release from Stainless Steel on Temperature and Water Vapor

    DOE PAGES

    Shmayda, W. T.; Sharpe, M.; Boyce, A. M.; ...

    2015-09-15

    The impact of water vapor and temperature on the release of tritium from stainless steel was studied. Degreased stainless steel samples loaded with tritium at room temperature following a 24-h degassing in vacuum at room temperature were subjected to increasing temperatures or humidity. In general, increasing either the sample temperature or the humidity causes an increased quantity of tritium to be removed. Increasing the temperature to 300°C in a dry gas stream results in a significant release of tritium and is therefore an effective means for reducing the tritium inventory in steel. For humid purges at 30°C, a sixfold increasemore » in humidity results in a tenfold increase in the peak outgassing rate. Increasing the humidity from 4 parts per million (ppm) to 1000 ppm when the sample temperature is 100°C causes a significant increase in the tritium outgassing rate. Finally, a simple calculation shows that only 15% of the activity present in the sample was removed in these experiments, suggesting that the surface layer of adsorbed water participates in regulating tritium desorption from the surface.« less

  4. Evaluating All-Metal Valves for Use in a Tritium Environment

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

    Houk, L.; Payton, A.

    In the tritium gas processing system, it is desired to minimize polymer components due to their degradation from tritium exposure (beta decay). One source of polymers in the tritium process is valve components. A vendor has been identified that manufactures a valve that is marketed as being made from all-metal construction. This manufacturer, Ham-Let Group, manufactures a diaphragm valve (3LE series) that claims to be made entirely of metal. SRNL procured twelve (12) Ham-Let diaphragm valves for characterization and evaluation. The characterization tests include identification of the maximum pressure of these valves by performing pressure and burst tests. Leak testsmore » were performed to ensure the valves do not exceed the acceptable leak rate for tritium service. These valves were then cycled in a nitrogen gas and/or vacuum environment to ensure they would be durable in a process environment. They were subsequently leak tested per ASTM protocol to ensure that the valves maintained their leak tight integrity. A detailed material analysis was also conducted to determine hydrogen and tritium compatibility.« less

  5. In-Vessel Tritium Retention and Removal in ITER-FEAT

    NASA Astrophysics Data System (ADS)

    Federici, G.; Brooks, J. N.; Iseli, M.; Wu, C. H.

    Erosion of the divertor and first-wall plasma-facing components, tritium uptake in the re-deposited films, and direct implantation in the armour material surfaces surrounding the plasma, represent crucial physical issues that affect the design of future fusion devices. In this paper we present the derivation, and discuss the results, of current predictions of tritium inventory in ITER-FEAT due to co-deposition and implantation and their attendant uncertainties. The current armour materials proposed for ITER-FEAT are beryllium on the first-wall, carbon-fibre-composites on the divertor plate near the separatrix strike points, to withstand the high thermal loads expected during off-normal events, e.g., disruptions, and tungsten elsewhere in the divertor. Tritium co-deposition with chemically eroded carbon in the divertor, and possibly with some Be eroded from the first-wall, is expected to represent the dominant mechanism of in-vessel tritium retention in ITER-FEAT. This demands efficient in-situ methods of mitigation and retrieval to avoid frequent outages due to the reaching of precautionary operating limits set by safety considerations (e.g., ˜350 g of in-vessel co-deposited tritium) and for fuel economy reasons. Priority areas where further R&D work is required to narrow the remaining uncertainties are also briefly discussed.

  6. Effects of glacial meltwater inflows and moat freezing on mixing in an ice-covered antarctic lake as interpreted from stable isotope and tritium distributions

    USGS Publications Warehouse

    Miller, L.G.; Aiken, G.R.

    1996-01-01

    Perennially ice-covered lakes in the McMurdo Dry Valleys have risen several meters over the past two decades due to climatic warming and increased glacial meltwater inflow. To elucidate the hydrologic responses to changing climate and the effects on lake mixing processes we measured the stable isotope (??18O and ??D) and tritium concentrations of water and ice samples collected in the Lake Fryxell watershed from 1987 through 1990. Stable isotope enrichment resulted from evaporation in stream and moat samples and from sublimation in surface lake-ice samples. Tritium enrichment resulted from exchange with the postnuclear atmosphere in stream and moat samples. Rapid injection of tritiated water into the upper water column of the make and incorporation of this water into the ice cover resulted in uniformly elevated tritium contents (> 3.0 TU) in these reservoirs. Tritium was also present in deep water, suggesting that a component of bottom water was recently at the surface. During summer, melted lake ice and stream water forms the moat. Water excluded from ice formation during fall moat freezing (enriched in solutes and tritium, and depleted in 18O and 2H relative to water below 15-m depth) may sink as density currents to the bottom of the lake. Seasonal lake circulation, in response to climate-driven surface inflow, is therefore responsible for the distribution of both water isotopes and dissolved solutes in Lake Fryxell.

  7. The Stark Effect on the Wave Function of Tritium in Relativistic Condition

    NASA Astrophysics Data System (ADS)

    Supriadi, B.; Prastowo, S. H. B.; Bahri, S.; Ridlo, Z. R.; Prihandono, T.

    2018-03-01

    Tritium Atom is one of the isotopes of Hydrogen that has two Neutrons in the nucleus and an electron that surrounds the nucleus. The Stark Effect is an effect of a shift or polarization of the atomic spectrum caused by the external electrostatic field. The interaction between the electrons and the external electric field can be reviewed using an approximation method of perturbation theory. The perturbation theory used is a time Independent non-degenerate perturbation and reviewed to second order to obtain correction of Tritium Atomic wave function. The condition that used in the system is a relativistic condition by reviewing the movement of electrons within the Atom. The effects of relativity also affect the correction of the wave function of Atom Tritium in the ground state. Tritium is radioactive material that is still relatively safe, and one of the applications of Tritium Atom is on the battery of betavoltaics (Nano Tritium Battery).

  8. Tritium as an indicator of ground-water age in Central Wisconsin

    USGS Publications Warehouse

    Bradbury, Kenneth R.

    1991-01-01

    In regions where ground water is generally younger than about 30 years, developing the tritium input history of an area for comparison with the current tritium content of ground water allows quantitative estimates of minimum ground-water age. The tritium input history for central Wisconsin has been constructed using precipitation tritium measured at Madison, Wisconsin and elsewhere. Weighted tritium inputs to ground water reached a peak of over 2,000 TU in 1964, and have declined since that time to about 20-30 TU at present. In the Buena Vista basin in central Wisconsin, most ground-water samples contained elevated levels of tritium, and estimated minimum ground-water ages in the basin ranged from less than one year to over 33 years. Ground water in mapped recharge areas was generally younger than ground water in discharge areas, and estimated ground-water ages were consistent with flow system interpretations based on other data. Estimated minimum ground-water ages increased with depth in areas of downward ground-water movement. However, water recharging through thick moraine sediments was older than water in other recharge areas, reflecting slower infiltration through the sandy till of the moraine.

  9. Tritium distribution in ground water around large underground fusion explosions

    USGS Publications Warehouse

    Stead, F.W.

    1963-01-01

    Tritium will be released in significant amounts from large underground nuclear fusion explosions in the Plowshare Program. The tritium could become highly concentrated in nearby ground waters, and could be of equal or more importance as a possible contaminant than other long-lived fission-product and induced radionuclides. Behavior of tritiated water in particular hydrologic and geologic environments, as illustrated by hypothetical explosions in dolomite and tuff, must be carefully evaluated to predict under what conditions high groundwater concentrations of tritium might occur.

  10. The Windowless Gaseous Tritium Source (WGTS) of the KATRIN experiment

    NASA Astrophysics Data System (ADS)

    Heizmann, Florian; Seitz-Moskaliuk, Hendrik; KATRIN Collaboration

    2017-09-01

    The Karlsruhe Tritium Neutrino Experiment (KATRIN) will perform a direct, kinematics-based measurement of the neutrino mass with a sensitivity of 200 meV (90 % C. L.), which will be reached after 3 years of measurement time. The neutrino mass is obtained by investigating the shape of the energy spectrum of tritium β-decay electrons close to the endpoint at 18.6 keV with a spectrometer of MAC-E filter type. This contribution reviews the current status of the tritium source cryostat and magnet system which is currently in its first cool-down phase. Furthermore, the next steps of the comprehensive pre-tritium measurement programme to characterise the apparatus and investigate important systematics are outlined. This work is supported by BMBF (05A14VK2) and the Helmholtz Association.

  11. Incorporation of organic tritium (3H) by marine organisms and sediment in the severn estuary/Bristol channel (UK).

    PubMed

    McCubbin, D; Leonard, K S; Bailey, T A; Williams, J; Tossell, P

    2001-10-01

    Discharges of tritium (3H) into the Severn estuary/Bristol Channel (UK) arise from the authorized release of wastes from nuclear power plants at Hinkley Point and Berkley/Oldbury and from the Nycomed-Amersham radiochemical plant, via the sewer system, at Cardiff. The wastes from the nuclear power plants probably consist almost entirely of 3H2O, whereas those from the radiochemical plant also include uncharacterized 3H labelled organic compounds. The total 3H concentrations in demersal fish and other benthic organisms in the vicinity of the Cardiff Eastern sewer outfall are significantly elevated compared to those observed around other UK nuclear establishments. Concentrations in filtered seawater were approximately 10 Bq kg(-1) whilst levels in surface sediment, seaweed (Fucus vesiculosis) and mussels (Mytilus edulis)/flounder (Platichthys flesus) were in the order of 6 x 10(2), 2 x 10(3), and 10(5) Bq kg(-1) (dry weight), respectively. Almost all the 3H found in sediment and biota were organically bound tritium (OBT). The high concentration in these materials, relative to that in seawater, is due to the presence of bioavailable organic 3H labelled compounds in the radiochemical waste. It is suggested that bioaccumulation of 3H by benthic organisms and demersal fish occurs primarily via a pathway of physico-chemical sorption/bacterial transformation of dissolved 3H labelled organic compounds into particulate organic matter, and subsequent transfer up a web of sediment dwelling microbes and meiofauna. Variations in 3H accumulation between individual organisms have been interpreted in terms of their different feeding behaviour. Relatively low concentrations were observed in the herbivorous winkle (Littorina littorea) and the pelagic Sprat (Spratus spratus) compared with other benthic organisms and demersal fish. The elevated 3H concentrations in seafood, due to bioaccumulation of OBT, have low radiological significance even for the local critical group of seafood

  12. Tritium contamination at EG&G/EM in North Las Vegas, Nevada

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

    Sowell, C.V.; Arent, L.J.

    1996-06-01

    The tritium contamination discovered at the EG&G Energy Measurements (EG&G/EM) facility in North Las Vegas, Nevada, on 20 April 1995, could have been averted by good health physics practices and/or adequate management oversight. Scandium tritide (ScT{sub 3}) targets were installed for use in sealed tube neutron generators at EG&G/EM. In addition, EG&G/EM was also storing zirconium tritide (ZrT{sub 3}) and titanium tritide (TiT{sub 3}) foils. Since the targets were classified as sealed sources, the appropriate administrative and engineering control measures such as relocating targets/sources, air monitoring, bioassay, waste stream management, labeling/posting and training were not implemented. In all there weremore » six unreported incidents of tritium contamination from March 1994 to July 1995. Swipe surveys revealed areas exceeding the action level of 10,000 dpm/100 cm{sup 2} by up to three orders of magnitude. After reclassifying the targets as unsealed sources, a bioassay program was instituted, and the results were higher than expected for three employees. The doses assigned to the three individuals working in the contaminated area were 35, 58, and 61 mrem committed effective dose equivalent. Though the doses were low, the decontamination costs were in excess of $350,000.00. An investigation, was initiated by the U.S. Department of Energy Nevada Operations Office to analyze the events that led to the tritium contamination and recommend actions to prevent recurrence. Event and causal factor charting, Project Evaluation Tree (PET) analysis techniques, and root cause analysis, were used to evaluate management systems, causal sequences, and systems factors contributing to the tritium release.« less

  13. Effectiveness Monitoring Report, MWMF Tritium Phytoremediation Interim Measures.

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

    Hitchcock, Dan; Blake, John, I.

    2003-02-10

    This report describes and presents the results of monitoring activities during irrigation operations for the calendar year 2001 of the MWMF Interim Measures Tritium Phytoremediation Project. The purpose of this effectiveness monitoring report is to provide the information on instrument performance, analysis of CY2001 measurements, and critical relationships needed to manage irrigation operations, estimate efficiency and validate the water and tritium balance model.

  14. Tritium-powered radiation sensor network

    NASA Astrophysics Data System (ADS)

    Litz, Marc S.; Russo, Johnny A.; Katsis, Dimos

    2016-05-01

    Isotope power supplies offer long-lived (100 years using 63Ni), low-power energy sources, enabling sensors or communications nodes for the lifetime of infrastructure. A tritium beta-source (12.5-year half-life) encapsulated in a phosphor-lined vial couples directly to a photovoltaic (PV) to generate a trickle current into an electrical load. An inexpensive design is described using commercial-of-the-shelf (COTS) components that generate 100 μWe for nextgeneration compact electronics/sensors. A matched radiation sensor has been built for long-duration missions utilizing microprocessor-controlled sleep modes, low-power electronic components, and a passive interrupt driven environmental wake-up. The low-power early-warning radiation detector network and isotope power source enables no-maintenance mission lifetimes.

  15. Limitation of tritium outgassing from tritiated solid waste drums

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

    Liger, K.; Trabuc, P.; Lefebvre, X.

    2015-03-15

    In the framework of the development of fusion thermonuclear reactors, tritiated solid waste is foreseen and will have to be managed. The management of tritiated waste implies limitations in terms of activity and tritium degassing. The degassing tritium can be under the form of tritiated hydrogen, tritiated water and, in some specific cases, negligible amount of tritiated volatile organic compound. Hence, considering the major forms of degassing tritium, CEA has developed a mixed-compound dedicated to tritium trapping in drums. Based on several experiments, the foreseen mixed compound is composed of MnO{sub 2}, Ag{sub 2}O, Pt and molecular sieve, the threemore » first species having the ability to convert tritiated hydrogen into tritiated water and the last one acting as a trap for tritiated water. To assess the performance of the trapping mixture, experimental tests were performed at room temperature on tritiated dust composed of beryllium and carbon. It was shown that the metallic oxides mixture used for tritiated hydrogen conversion is efficient and that tritiated water adsorption was limited due to an inefficient regeneration of the molecular sieve prior to its use. Apart from this point, the tritium release from waste was reduced by a factor of 5.5, which can be improved up to 87 if the adsorption step is efficient.« less

  16. Regeneration and tritium recovery from the large JET neutral injection cryopump system after the FTE

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

    Obert, W.; Bell, A.; Davies, J.

    1992-12-01

    Neutral Beam Injection (NBI) was used to introduce tritium into the plasma for the First Tritium Experiment In addition to the decisive advantage of depositing the tritium into the centre of the plasma, the use of NBI also minimized the total quantity of tritium introduced into the Torus and the contamination of the vacuum vessel. However, because of the relatively low gas efficiency of the positive ion injection system approximately 95% of the total quantity of tritium introduced was pumped by the large condensation cryopumps which form an integral part of the injector. Several hardware and associated software changes weremore » implemented in order to making provision for possible fault scenarios during operation with tritium and to ensure complete regeneration of the tritium from the cryopumps. The tritium released after all subsequent regeneration`s has been monitored carefully in order to determine the amount of tritium retained by the black anodized liquid nitrogen panel surfaces of the cryopump and to compare it with experiments at TSTA on JET samples before the FTE.« less

  17. Modeling and experiments on tritium permeation in fusion reactor blankets

    NASA Astrophysics Data System (ADS)

    Holland, D. F.; Longhurst, G. R.

    The determination of tritium loss from helium-cooled fusion breeding blankets are discussed. The issues are: (1) applicability of present models to permeation at low tritium pressures; (2) effectiveness of oxide layers in reducing permeation; (3) effectiveness of hydrogen addition as a means to lower tritium permeation; and (4) effectiveness of conversion to tritiated water and subsequent trapping to reduce permeation. Theoretical models applicable to these issues are discussed, and results of experiments in two areas are presented; permeation of mixtures of hydrogen isotopes and conversion to tritiated water.

  18. Recovery of tritium from tritiated molecules

    DOEpatents

    Swansiger, William A.

    1987-01-01

    A method of recovering tritium from tritiated compounds comprises the steps of heating tritiated water and other co-injected tritiated compounds in a preheater to temperatures of about 600.degree. C. The mixture is injected into a reactor charged with a mixture of uranium and uranium dioxide. The injected mixture undergoes highly exothermic reactions with the uranium causing reaction temperatures to occur in excess of the melting point of uranium, and complete decomposition of the tritiated compounds to remove tritium therefrom. The uranium dioxide functions as an insulating material and heat sink preventing the reactor side walls from attaining reaction temperatures to thereby minimize tritium permeation rates. The uranium dioxide also functions as a diluent to allow for volumetric expansion of the uranium as it is converted to uranium dioxide. The reactor vessel is preferably stainless steel of sufficient mass so as to function as a heat sink preventing the reactor side walls from approaching high temperatures. A disposable copper liner extends between the reaction chamber and stainless steel outer vessel to prevent alloying of the uranium with the outer vessel. Apparatus used to carry out the method of the invention is also disclosed.

  19. Plant-based plume-scale mapping of tritium contamination in desert soils

    USGS Publications Warehouse

    Andraski, Brian J.; Stonestrom, David A.; Michel, R.L.; Halford, K.J.; Radyk, J.C.

    2005-01-01

    Plant-based techniques were tested for field-scale evaluation of tritium contamination adjacent to a low-level radioactive waste (LLRW) facility in the Amargosa Desert, Nevada. Objectives were to (i) characterize and map the spatial variability of tritium in plant water, (ii) develop empirical relations to predict and map subsurface contamination from plant-water concentrations, and (iii) gain insight into tritium migration pathways and processes. Plant sampling [creosote bush, Larrea tridentata (Sessé & Moc. ex DC.) Coville] required one-fifth the time of soil water vapor sampling. Plant concentrations were spatially correlated to a separation distance of 380 m; measurement uncertainty accounted for <0.1% of the total variability in the data. Regression equations based on plant tritium explained 96 and 90% of the variation in root-zone and sub-root-zone soil water vapor concentrations, respectively. The equations were combined with kriged plant-water concentrations to map subsurface contamination. Mapping showed preferential lateral movement of tritium through a dry, coarse-textured layer beneath the root zone, with concurrent upward movement through the root zone. Analysis of subsurface fluxes along a transect perpendicular to the LLRW facility showed that upward diffusive-vapor transport dominates other transport modes beneath native vegetation. Downward advective-liquid transport dominates at one endpoint of the transect, beneath a devegetated road immediately adjacent to the facility. To our knowledge, this study is the first to document large-scale subsurface vapor-phase tritium migration from a LLRW facility. Plant-based methods provide a noninvasive, cost-effective approach to mapping subsurface tritium migration in desert areas.

  20. Accounting strategy of tritium inventory in the heavy water detritiation pilot plant from ICIT Rm. Valcea

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

    Bidica, N.; Stefanescu, I.; Cristescu, I.

    2008-07-15

    In this paper we present a methodology for determination of tritium inventory in a tritium removal facility. The method proposed is based on the developing of computing models for accountancy of the mobile tritium inventory in the separation processes, of the stored tritium and of the trapped tritium inventory in the structure of the process system components. The configuration of the detritiation process is a combination of isotope catalytic exchange between water and hydrogen (LPCE) and the cryogenic distillation of hydrogen isotopes (CD). The computing model for tritium inventory in the LPCE process and the CD process will be developedmore » basing on mass transfer coefficients in catalytic isotope exchange reactions and in dual-phase system (liquid-vapour) of hydrogen isotopes distillation process. Accounting of tritium inventory stored in metallic hydride will be based on in-bed calorimetry. Estimation of the trapped tritium inventory can be made by subtraction of the mobile and stored tritium inventories from the global tritium inventory of the plant area. Determinations of the global tritium inventory of the plant area will be made on a regular basis by measuring any tritium quantity entering or leaving the plant area. This methodology is intended to be applied to the Heavy Water Detritiation Pilot Plant from ICIT Rm. Valcea (Romania) and to the Cernavoda Tritium Removal Facility (which will be built in the next 5-7 years). (authors)« less

  1. Tritium-field betacells

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

    Walko, R.J.; Lincoln, R.C.; Baca, W.E.

    1991-01-01

    Betavoltaic power sources operate by converting the nuclear decay energy of beta-emitting radioisotopes into electricity. Since they are not chemically driven, they could operate at temperatures which would either be to hot or too cold for typical chemical batteries. Further, for long lived isotopes, they offer the possibility of multi-decade active lifetimes. Two approaches are being investigated: direct and indirect conversion. Direct conversion cells consist of semiconductor diodes similar to photovoltaic cells. Beta particle directly bombard these cells, generating electron-hole pairs in the semiconductor which are converted to useful power. Many using low power flux beta emitters, wide bandgap semiconductorsmore » are required to achieve useful conversion efficiencies. The combination of tritium, as the beta emitter, and gallium phosphide (GaP), as the semiconductor converter, was evaluated. Indirect conversion betacells first convert the beta energy to light with a phosphor, and then to electricity with photovoltaic cells. An indirect conversion power source using a tritium radioluminescent (RL) light is being investigated. Our analysis indicates that this approach has the potential for significant volume and cost savings over the direct conversion method. 7 refs., 11 figs.« less

  2. Organic matter controls of iron incorporation in growing sea ice

    NASA Astrophysics Data System (ADS)

    Janssens, Julie; Meiners, Klaus M.; Townsend, Ashley T.; Lannuzel, Delphine

    2018-03-01

    This study presents the first laboratory-controlled sea-ice growth experiment conducted under trace metal clean conditions. The role played by organic matter, in the incorporation of iron (Fe) into sea ice was investigated by means of laboratory ice-growth experiments using a titanium cold-finger apparatus. Experiments were also conducted to understand the role of extracellular polymeric substances (EPS) in the enrichment of ammonium in sea ice. Sea ice was grown from several seawater solutions containing different quantities and qualities of particulate Fe (PFe), dissolved Fe (DFe) and organic matter. Sea ice and seawater were analyzed for particulate organic carbon and nitrogen, macro-nutrients, extracellular EPS, PFe and DFe, and particulate aluminium. The experiments showed that biogenic PFe is preferentially incorporated into sea ice compared to lithogenic PFe. Furthermore, sea ice grown from ultra-violet (UV) and non-UV treated seawaters exhibits contrasting incorporation rates of organic matter and Fe. Whereas the effects of UV-treatments were not always significant, we do find indications that the type or organic matter controls the enrichment of Fe in forming sea ice.. Specifically, we come to the conclusion that the incorporation of DFe is favored by the presence of organic ligands in the source solution.

  3. Tritium release from neutron-irradiated Li 2O sintered pellets: porosity dependence

    NASA Astrophysics Data System (ADS)

    Tanifuji, Takaaki; Yamaki, Daiju; Takahashi, Tadashi; Iwamoto, Akira

    2000-12-01

    The tritium release behaviour from sintered Li 2O pellets of various densities (71-98.5% theoretical density, T.D.) has been investigated by heating tests at a constant rate. It is shown that the tritium release rate depends on porosity at densities above 87% T.D., while no dependence was observed at densities below 86% T.D. The tritium release process is thought to consist of three stages described as follows: (1) the liberation of tritium trapped at point defects due to their recovery (peak at around 570 K); (2) the advection through interconnected pores via adsorption and desorption on their inner walls and diffusion in the gas phase of interconnected pores (peak at around 620 K); (3) the dissolution and release of tritium trapped in closed pores (peaks at around 700, 830 and 1000 K).

  4. The use of dynamic modeling in assessing tritium phytoremediation

    Treesearch

    Karin T. Rebel; Susan J. Riha; John C. Seaman; Clinton d. Barton

    2005-01-01

    To minimize movement of tritium into surface waters at the Mixed Waste Management Facility at the Savannah River Site, tritiumcontaminated groundwater released to the surface along seeps in the hillside is being retained in a constructed pond and used to irrigate forest acreage that lies over the contaminated groundwater. Management of the application of tritium-...

  5. TRITIUM AND DECAY HELIUM EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF STAINLESS STEEL WELDMENTS

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

    Morgan, M; Scott West, S; Michael Tosten, M

    2007-08-31

    J-Integral fracture toughness tests were conducted on tritium-exposed-and-aged Types 304L and 21-6-9 stainless steel weldments in order to measure the combined effects of tritium and its decay product, helium-3 on the fracture toughness properties. Initially, weldments have fracture toughness values about three times higher than base-metal values. Delta-ferrite phase in the weld microstructure improved toughness provided no tritium was present in the microstructure. After a tritium-exposure-and-aging treatment that resulted in {approx}1400 atomic parts per million (appm) dissolved tritium, both weldments and base metals had their fracture toughness values reduced to about the same level. The tritium effect was greater inmore » weldments (67 % reduction vs. 37% reduction) largely because the ductile discontinuous delta-ferrite interfaces were embrittled by tritium and decay helium. Fracture toughness values decreased for both base metals and weldments with increasing decay helium content in the range tested (50-200 appm).« less

  6. Estimation of the tritium retention in ITER tungsten divertor target using macroscopic rate equations simulations

    NASA Astrophysics Data System (ADS)

    Hodille, E. A.; Bernard, E.; Markelj, S.; Mougenot, J.; Becquart, C. S.; Bisson, R.; Grisolia, C.

    2017-12-01

    Based on macroscopic rate equation simulations of tritium migration in an actively cooled tungsten (W) plasma facing component (PFC) using the code MHIMS (migration of hydrogen isotopes in metals), an estimation has been made of the tritium retention in ITER W divertor target during a non-uniform exponential distribution of particle fluxes. Two grades of materials are considered to be exposed to tritium ions: an undamaged W and a damaged W exposed to fast fusion neutrons. Due to strong temperature gradient in the PFC, Soret effect’s impacts on tritium retention is also evaluated for both cases. Thanks to the simulation, the evolutions of the tritium retention and the tritium migration depth are obtained as a function of the implanted flux and the number of cycles. From these evolutions, extrapolation laws are built to estimate the number of cycles needed for tritium to permeate from the implantation zone to the cooled surface and to quantify the corresponding retention of tritium throughout the W PFC.

  7. Tritium as an indicator of venues for nuclear tests.

    PubMed

    Lyakhova, O N; Lukashenko, S N; Mulgin, S I; Zhdanov, S V

    2013-10-01

    Currently, due to the Treaty on the Non-proliferation of Nuclear Weapons there is a highly topical issue of an accurate verification of nuclear explosion venues. This paper proposes to consider new method for verification by using tritium as an indicator. Detailed studies of the tritium content in the air were carried in the locations of underground nuclear tests - "Balapan" and "Degelen" testing sites located in Semipalatinsk Test Site. The paper presents data on the levels and distribution of tritium in the air where tunnels and boreholes are located - explosion epicentres, wellheads and tunnel portals, as well as in estuarine areas of the venues for the underground nuclear explosions (UNE). Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Low tritium partial pressure permeation system for mass transport measurement in lead lithium eutectic

    DOE PAGES

    Pawelko, R. J.; Shimada, M.; Katayama, K.; ...

    2015-11-28

    This paper describes a new experimental system designed to investigate tritium mass transfer properties in materials important to fusion technology. Experimental activities were carried out at the Safety and Tritium Applied Research (STAR) facility located at the Idaho National Laboratory (INL). The tritium permeation measurement system was developed as part of the Japan/US TITAN collaboration to investigate tritium mass transfer properties in liquid lead lithium eutectic (LLE) alloy. The experimental system is configured to measure tritium mass transfer properties at low tritium partial pressures. Initial tritium permeation scoping tests were conducted on a 1 mm thick α-Fe plate to determinemore » operating parameters and to validate the experimental technique. A second series of permeation tests was then conducted with the α-Fe plate covered with an approximately 8.5 mm layer of liquid lead lithium eutectic alloy (α-Fe/LLE). We present preliminary tritium permeation data for α-Fe and α-Fe/LLE at temperatures between 400 and 600°C and at tritium partial pressures between 1.7E-3 and 2.5 Pa in helium. Preliminary results for the α-Fe plate and α-Fe/LLE indicate that the data spans a transition region between the diffusion-limited regime and the surface-limited regime. In conclusion, additional data is required to determine the existence and range of a surface-limited regime.« less

  9. A SUITABLE TRITIUM CARRIER FOR GAS DISCHARGE TUBES

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

    Reifenschweiler, O.

    1959-10-31

    The application, especially in manufacturing processes, of radium and similar radioactive materials as priming agents in gas discharge tubes is very undesirable owing to the danger to health which they involve. To avoid this danger or to diminish it as much as possible, various attempts were made to employ tritium as a priming agent. This radioactive gas is especially suitable for this purpose because of its extremely soft beta radiation, the absence of hard gamma radiation, its high specific activity at a relatively low price, and above all its extremely high maximum permissible concentration in comparison with radium. To avoidmore » the handling of gaseous tritium, which is undesirable in manufacturing processes, the tritium is applied in a suspension of a tritiated titunium powder. On account of the small energy of the beta particles the grains of this titunium powder have to be extremely small. A powder prepared by careful milling and elutriation with grains of about 1 mu proved to be much too coarse. Only a few percent of the beta particles of the tritium then leave the titunium grains. However, by evaporation of titanium in an atmosphere of rare gases, a powder with a grain diameter of about 300 A is obtained. After absorption of the tritium by this titanium powder a suspension in an organic fluid is prepared by ultrasonic treatment. The electron-emitter surface is then very conveniently obtained by painting this suspension at the desired bremsstrahlung by means of a Geiger counter. The loss of electrons by absorption in the titanium is then only about 10%. (auth)« less

  10. Anthropogenic tritium in the Loire River estuary, France

    NASA Astrophysics Data System (ADS)

    Péron, O.; Gégout, C.; Reeves, B.; Rousseau, G.; Montavon, G.; Landesman, C.

    2016-12-01

    This work is carried out in the frame of a radioecological monitoring of anthropogenic tritium from upstream and downstream of several nuclear power plants along the Loire River to its estuary. This paper studies the variation of anthropogenic tritium species in the Loire River system from upstream to the mouth of the estuary. Tritiated water (HTO and HTO in sediment pore water) and organically bound tritium (OBT) forms were analysed after dedicated pre-treatments. The collected environmental samples consist in (i) surface-sediment and core samples from the river floor, (ii) surface and water column samples. A maximum 3H activity concentration of 26 ± 3 Bq·L- 1 in the Loire River estuary is obtained whereas an environmental background level around 1 Bq·L- 1 is determined for a non influenced continental area by anthropogenic activities. The European follow-up indicator used as a screening value is 100 Bq·L- 1. The conservative tritium behaviour was used in order to characterize the tidal regime and river flow influences in the mixing zone of the Loire River estuary. Furthermore, OBT levels and total organically carbon (TOC) content are explored. Finally, ratios of OBT relative to HTO in sediment pore water in surface-sediment and core samples are also discussed.

  11. Tritium labeling of organic compounds deposited on porous structures

    DOEpatents

    Ehrenkaufer, Richard L. E.; Wolf, Alfred P.; Hembree, Wylie C.

    1979-01-01

    An improved process for labeling organic compounds with tritium is carried out by depositing the selected compound on the extensive surface of a porous structure such as a membrane filter and exposing the membrane containing the compound to tritium gas activated by the microwave discharge technique. The labeled compound is then recovered from the porous structure.

  12. Modeling and analysis of tritium dynamics in a DT fusion fuel cycle

    NASA Astrophysics Data System (ADS)

    Kuan, William

    1998-11-01

    A number of crucial design issues have a profound effect on the dynamics of the tritium fuel cycle in a DT fusion reactor, where the development of appropriate solutions to these issues is of particular importance to the introduction of fusion as a commercial system. Such tritium-related issues can be classified according to their operational, safety, and economic impact to the operation of the reactor during its lifetime. Given such key design issues inherent in next generation fusion devices using the DT fuel cycle development of appropriate models can then lead to optimized designs of the fusion fuel cycle for different types of DT fusion reactors. In this work, two different types of modeling approaches are developed and their application to solving key tritium issues presented. For the first approach, time-dependent inventories, concentrations, and flow rates characterizing the main subsystems of the fuel cycle are simulated with a new dynamic modular model of a fusion reactor's fuel cycle, named X-TRUFFLES (X-Windows TRitiUm Fusion Fuel cycLE dynamic Simulation). The complex dynamic behavior of the recycled fuel within each of the modeled subsystems is investigated using this new integrated model for different reactor scenarios and design approaches. Results for a proposed fuel cycle design taking into account current technologies are presented, including sensitivity studies. Ways to minimize the tritium inventory are also assessed by examining various design options that could be used to minimize local and global tritium inventories. The second modeling approach involves an analytical model to be used for the calculation of the required tritium breeding ratio, i.e., a primary design issue which relates directly to the feasibility and economics of DT fusion systems. A time-integrated global tritium balance scheme is developed and appropriate analytical expressions are derived for tritium self-sufficiency relevant parameters. The easy exploration of the large

  13. RADIOLYTIC GAS PRODUCTION RATES OF POLYMERS EXPOSED TO TRITIUM GAS

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

    Clark, E.

    Data from previous reports on studies of polymers exposed to tritium gas is further analyzed to estimate rates of radiolytic gas production. Also, graphs of gas release during tritium exposure from ultrahigh molecular weight polyethylene (UHMW-PE), polytetrafluoroethylene (PTFE, a trade name is Teflon®), and Vespel® polyimide are re-plotted as moles of gas as a function of time, which is consistent with a later study of tritium effects on various formulations of the elastomer ethylene-propylene-diene monomer (EPDM). These gas production rate estimates may be useful while considering using these polymers in tritium processing systems. These rates are valid at least formore » the longest exposure times for each material, two years for UHMW-PE, PTFE, and Vespel®, and fourteen months for filled and unfilled EPDM. Note that the production “rate” for Vespel® is a quantity of H{sub 2} produced during a single exposure to tritium, independent of length of time. The larger production rate per unit mass for unfilled EPDM results from the lack of filler- the carbon black in filled EPDM does not produce H{sub 2} or HT. This is one aspect of how inert fillers reduce the effects of ionizing radiation on polymers.« less

  14. Suppression of tritium retention in remote areas of ITER by nonperturbative reactive gas injection.

    PubMed

    Tabarés, F L; Ferreira, J A; Ramos, A; van Rooij, G; Westerhout, J; Al, R; Rapp, J; Drenik, A; Mozetic, M

    2010-10-22

    A technique based on reactive gas injection in the afterglow region of the divertor plasma is proposed for the suppression of tritium-carbon codeposits in remote areas of ITER when operated with carbon-based divertor targets. Experiments in a divertor simulator plasma device indicate that a 4  nm/min deposition can be suppressed by addition of 1  Pa·m³ s⁻¹ ammonia flow at 10 cm from the plasma. These results bolster the concept of nonperturbative scavenger injection for tritium inventory control in carbon-based fusion plasma devices, thus paving the way for ITER operation in the active phase under a carbon-dominated, plasma facing component background.

  15. A model function of the global bomb tritium distribution in precipitation, 1960-1986

    NASA Astrophysics Data System (ADS)

    Doney, Scott C.; Glover, David M.; Jenkins, William J.

    1992-04-01

    The paper presents a model function for predicting the annual mean concentration of the decay-corrected bomb tritium in precipitation over the time period 1960-1986. The model was developed using the World Meteorological Organization/International Atomic Energy Agency data for tritium precipitation. The resulting tritium function is global in scope and includes both marine and continental data. Estimates were obtained of the seasonal cycle of tritium in precipitation, which may be useful for studying atmospheric transport and oceanic processes, such as convection and subduction that occur on seasonal timescales.

  16. Preliminary Tritium Management Design Activities at ORNL

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

    Harrison, Thomas J.; Felde, David K.; Logsdon, Randall J.

    2016-09-01

    Interest in salt-cooled and salt-fueled reactors has increased over the last decade (Forsberg et al. 2016). Several private companies and universities in the United States, as well as governments in other countries, are developing salt reactor designs and/or technology. Two primary issues for the development and deployment of many salt reactor concepts are (1) the prevention of tritium generation and (2) the management of tritium to prevent release to the environment. In 2016, the US Department of Energy (DOE) initiated a research project under the Advanced Reactor Technology Program to (1) experimentally assess the feasibility of proposed methods for tritiummore » mitigation and (2) to perform an engineering demonstration of the most promising methods. This document describes results from the first year’s efforts to define, design, and build an experimental apparatus to test potential methods for tritium management. These efforts are focused on producing a final design document as the basis for the apparatus and its scheduled completion consistent with available budget and approvals for facility use.« less

  17. Drinking water standard for tritium-what's the risk?

    PubMed

    Kocher, D C; Hoffman, F O

    2011-09-01

    This paper presents an assessment of lifetime risks of cancer incidence associated with the drinking water standard for tritium established by the U.S. Environmental Protection Agency (USEPA); this standard is an annual-average maximum contaminant level (MCL) of 740 Bq L(-1). This risk assessment has several defining characteristics: (1) an accounting of uncertainty in all parameters that relate a given concentration of tritium in drinking water to lifetime risk (except the number of days of consumption of drinking water in a year and the number of years of consumption) and an accounting of correlations of uncertain parameters to obtain probability distributions that represent uncertainty in estimated lifetime risks of cancer incidence; (2) inclusion of a radiation effectiveness factor (REF) to represent an increased biological effectiveness of low-energy electrons emitted in decay of tritium compared with high-energy photons; (3) use of recent estimates of risks of cancer incidence from exposure to high-energy photons, including the dependence of risks on an individual's gender and age, in the BEIR VII report; and (4) inclusion of risks of incidence of skin cancer, principally basal cell carcinoma. By assuming ingestion of tritium in drinking water at the MCL over an average life expectancy of 80 y in females and 75 y in males, 95% credibility intervals of lifetime risks of cancer incidence obtained in this assessment are (0.35, 12) × 10(-4) in females and (0.30, 15) × 10(-4) in males. Mean risks, which are considered to provide the best single measure of expected risks, are about 3 × 10(-4) in both genders. In comparison, USEPA's point estimate of the lifetime risk of cancer incidence, assuming a daily consumption of drinking water of 2 L over an average life expectancy of 75.2 y and excluding an REF for tritium and incidence of skin cancer, is 5.6 × 10(-5). Probability distributions of annual equivalent doses to the whole body associated with the drinking

  18. Process for recovering tritium from molten lithium metal

    DOEpatents

    Maroni, Victor A.

    1976-01-01

    Lithium tritide (LiT) is extracted from molten lithium metal that has been exposed to neutron irradiation for breeding tritium within a thermonuclear or fission reactor. The extraction is performed by intimately contacting the molten lithium metal with a molten lithium salt, for instance, lithium chloride - potassium chloride eutectic to distribute LiT between the salt and metal phases. The extracted tritium is recovered in gaseous form from the molten salt phase by a subsequent electrolytic or oxidation step.

  19. Lithium aluminate/zirconium material useful in the production of tritium

    DOEpatents

    Cawley, W.E.; Trapp, T.J.

    A composition is described useful in the production of tritium in a nuclear reactor. Lithium aluminate particles are dispersed in a matrix of zirconium. Tritium produced by the reactor of neutrons with the lithium are absorbed by the zirconium, thereby decreasing gas pressure within capsules carrying the material.

  20. Lithium aluminate/zirconium material useful in the production of tritium

    DOEpatents

    Cawley, W.E.; Trapp, T.J.

    1984-10-09

    A composition is described useful in the production of tritium in a nuclear reactor. Lithium aluminate particles are dispersed in a matrix of zirconium. Tritium produced by the reactor of neutrons with the lithium are absorbed by the zirconium, thereby decreasing gas pressure within capsules carrying the material.

  1. Lithium aluminate/zirconium material useful in the production of tritium

    DOEpatents

    Cawley, William E.; Trapp, Turner J.

    1984-10-09

    A composition is described useful in the production of tritium in a nuclear eactor. Lithium aluminate particles are dispersed in a matrix of zirconium. Tritium produced by the reactor of neutrons with the lithium are absorbed by the zirconium, thereby decreasing gas pressure within capsules carrying the material.

  2. Tritium retention in S-65 beryllium after 100 eV plasma exposure

    NASA Astrophysics Data System (ADS)

    Causey, Rion A.; Longhurst, Glen R.; Harbin, Wally

    1997-02-01

    The tritium plasma experiment (TPE) has been used to measure the retention of tritium in S-65 beryllium under conditions similar to that expected for the international thermonuclear experimental reactor (ITER). Beryllium samples 2 mm thick and 50 mm in diameter were exposed to a plasma of tritium and deuterium. The particle flux striking the samples was varied from approximately 1 × 10 17 ( D + T)/ cm2s up to about 3 × 10 18 ( D + T)/ cm2s. The beryllium samples were negatively biased to elevate the energy of the impinging ions to 100 eV. The temperature of the samples was varied from 373 K to 973 K. Exposure times of 1 h were used. Subsequent to the plasma exposure, the samples were outgassed in a separate system where 99% He and 1% H 2 gas was swept over the samples during heating. The sweep gas along with the released tritium was sent through an ionization chamber, through a copper oxide catalyst bed, and into a series of glycol bubblers. The amount of released tritium was determined both by the ionization chamber and by liquid scintillation counting of the glycol. Tritium retention in the beryllium disks varied from a high of 2.4 × 10 17 ( D + T)/ cm2 at 373 K to a low of 1 × 10 16 ( D + T)/ cm2 at 573 K. For almost every case, the tritium retention in the beryllium was less than that calculated using the C = 0 boundary condition at the plasma facing surface. It is believed that this lower than expected retention is due to rapid release of tritium from the large specific surface area created in the implant zone due to the production of voids, bubbles, and blisters.

  3. A new tritium monitor design based on plasma source ion implantation technique

    NASA Astrophysics Data System (ADS)

    Nassar, Rafat Mohammad

    Tritium is an important isotope of hydrogen. The availability of tritium in our environment is manifest through both natural and artificial sources. Consequently, the requirement for tritium handling and usage will continue to increase in the future. An important future contributor is nuclear fusion power plants and facilities. Essential safety regulations and procedures require effective monitoring and measurements of tritium concentrations in workplaces. The unique characteristics of tritium impose an important role on the criteria for its detection and measurement. As tritium decays by the emission of soft beta particles, maximum 18 keV, it cannot be readily detected by commonly used detectors. Specially built monitors are required. Additional complications occur due to the presence of other radioactive isotopes or ambient radiation fields and because of the high diffusivity of tritium. When it is in oxidized form it is 25000 times more hazardous biologically than when in elemental form. Therefore, contamination of the monitor is expected and compound specific monitors are important. A summary is given of the various well known methods of detecting tritium-in-air. This covers the direct as well as the indirect measuring techniques, although each has been continually improved and further developed, nevertheless, each has its own limitations. Ionization chambers cannot discriminate against airborne P emitters. Proportional counters have a narrow operating range, 3-4 decades, and have poor performance in relatively high humid environments and require a dry counting gas. Liquid scintillation counters are sensitive, but inspection of the sample is slow and they produce chemical liquid waste. A new way to improve the sensitivity of detecting tritium with plastic scintillators has been developed. The technique is based on a non-line-of-sight implantation of tritium ions into a 20 mum plastic scintillator using a plasma source ion implantation (PSII) technique, This

  4. 2017 Accomplishments – Tritium Aging Studies on Stainless Steel Weldments and Heat-Affected Zones

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

    Morgan, Michael J.; Hitchcock, Dale; Krentz, Tim

    In this study, the combined effects tritium and decay helium in forged and welded Types 304L and 21-6-9 stainless steels were studied. To measure these effects, fracture mechanic specimens were thermally precharged with tritium and aged for approximately 17 years to build in decay helium from tritium decay prior to testing. The results are compared to earlier measurements on the same alloys and weldments (4-5, 8-9). In support of Enhanced Surveillance, “Tritium Effects on Materials”, the fracture toughness properties of long-aged tritium-charged stainless-steel base metals and weldments were measured and compared to earlier measurements. The fracture-toughness data were measured bymore » thermally precharging as-forged and as-welded specimens with tritium gas at 34.5 MPa and 350°C and aging for approximately 17 years to build-in decay helium prior to testing. These data result from the longest aged specimens ever tested in the history of the tritium effects programs at Savannah River and the fracture toughness values measured were the lowest ever recorded for tritium-exposed stainless steel. For Type 21-6-9 stainless steel, fracture toughness values were reduced to less than 2-4% of the as-forged values to 41 lbs / in specimens that contained more than 1300 appm helium from tritium decay. The fracture toughness properties of long-aged weldments were also measured. The fracture toughness reductions were not as severe because the specimens did not retain as much tritium from the charging and aging as did the base metals. For Type 304L weldments, the specimens in this study contained approximately 600 appm helium and their fracture toughness values averaged 750 lbs / in. The results for other steels and weldments are reported and additional tests will be conducted during FY18.« less

  5. Effect of tritium and decay helium on the fracture toughness properties of stainless steel weldments

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

    Morgan, M. J.; West, S.; Tosten, M. H.

    2008-07-15

    J-Integral fracture toughness tests were conducted on tritium-exposed-and- aged Types 304L and 21-6-9 stainless steel weldments in order to measure the combined effects of tritium and its decay product, helium-3 on the fracture toughness properties. Initially, weldments have fracture toughness values about three times higher than base-metal values. Delta-ferrite phase in the weld microstructure improved toughness provided no tritium was present in the microstructure. After a tritium-exposure-and-aging treatment that resulted in {approx}1400 atomic parts per million (appm) dissolved tritium, both weldments and base metals had their fracture toughness values reduced to about the same level. The tritium effect was greatermore » in weldments (67 % reduction vs. 37% reduction) largely because the ductile discontinuous delta-ferrite phase was embrittled by tritium and decay helium. For both base metals and weldments, fracture toughness values decreased with increasing decay helium content in the range tested (50-800 appm). (authors)« less

  6. Tritium in waters of international importance in 1981-1984

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

    Anisimov, V.V.; Blinov, V.A.; Gedeonov, L.I.

    1988-03-01

    A study has been carried out on the radiation situation with respect to tritium in the drainage basin of the Baltic Sea and in the Soviet section of the Danube in the period of 1981-1984. Pollution of the Baltic during this period turned out to be quite constant and coincident with the tritium level of the preceding five years. Concentrations increased slightly in the Gulf of Riga and in a number of rivers flowing into the Baltic (Daugava, Pirita, etc.). In the same period the tritium contamination of Danube water was 2-3 times greater that of the Baltic. The tritiummore » content of the Baltic was calculated: its average value in the period 1981-1984 was 1.56 x 10/sup 17/ Bq.« less

  7. TRITIUM EFFECTS ON DYNAMIC MECHANICAL PROPERTIES OF POLYMERIC MATERIALS

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

    Clark, E

    2008-11-12

    Dynamic mechanical analysis has been used to characterize the effects of tritium gas (initially 1 atm. pressure, ambient temperature) exposure over times up to 2.3 years on several thermoplastics-ultrahigh molecular weight polyethylene (UHMW-PE), polytetrafluoroethylene (PTFE), and Vespel{reg_sign} polyimide, and on several formulations of elastomers based on ethylene propylene diene monomer (EPDM). Tritium exposure stiffened the elastic modulus of UHMW-PE up to about 1 year and then softened it, and reduced the viscous response monotonically with time. PTFE initially stiffened, however the samples became too weak to handle after nine months exposure. The dynamic properties of Vespel{reg_sign} were not affected. Themore » glass transition temperature of the EPDM formulations increased approximately 4 C. following three months tritium exposure.« less

  8. A Next Generation Digital Counting System For Low-Level Tritium Studies (Project Report)

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

    Bowman, P.

    2016-10-03

    Since the early seventies, SRNL has pioneered low-level tritium analysis using various nuclear counting technologies and techniques. Since 1999, SRNL has successfully performed routine low-level tritium analyses with counting systems based on digital signal processor (DSP) modules developed in the late 1990s. Each of these counting systems are complex, unique to SRNL, and fully dedicated to performing routine tritium analyses of low-level environmental samples. It is time to modernize these systems due to a variety of issues including (1) age, (2) lack of direct replacement electronics modules and (3) advances in digital signal processing and computer technology. There has beenmore » considerable development in many areas associated with the enterprise of performing low-level tritium analyses. The objective of this LDRD project was to design, build, and demonstrate a Next Generation Tritium Counting System (NGTCS), while not disrupting the routine low-level tritium analyses underway in the facility on the legacy counting systems. The work involved (1) developing a test bed for building and testing new counting system hardware that does not interfere with our routine analyses, (2) testing a new counting system based on a modern state of the art DSP module, and (3) evolving the low-level tritium counter design to reflect the state of the science.« less

  9. Vertical profile of tritium concentration in air during a chronic atmospheric HT release.

    PubMed

    Noguchi, Hiroshi; Yokoyama, Sumi

    2003-03-01

    The vertical profiles of tritium gas and tritiated water concentrations in air, which would have an influence on the assessment of tritium doses as well as on the environmental monitoring of tritium, were measured in a chronic tritium gas release experiment performed in Canada in 1994. While both of the profiles were rather uniform during the day because of atmospheric mixing, large gradients of the profiles were observed at night. The gradient coefficients of the profiles were derived from the measurements. Correlations were analyzed between the gradient coefficients and meteorological conditions: solar radiation, wind speed, and turbulent diffusivity. It was found that the solar radiation was highly correlated with the gradient coefficients of tritium gas and tritiated water profiles and that the wind speed and turbulent diffusivity showed weaker correlations with those of tritiated water profiles. A one-dimensional tritium transport model was developed to analyze the vertical diffusion of tritiated water re-emitted from the ground into the atmosphere. The model consists of processes of tritium gas deposition to soil including oxidation into tritiated water, reemission of tritiated water, dilution of tritiated water in soil by rain, and vertical diffusion of tritiated water in the atmosphere. The model accurately represents the accumulation of tritiated water in soil water and the time variations and vertical profiles of tritiated water concentrations in air.

  10. Application of tritium in precipitation and baseflow in Japan: a case study of groundwater transit times and storage in Hokkaido watersheds

    NASA Astrophysics Data System (ADS)

    Gusyev, Maksym A.; Morgenstern, Uwe; Stewart, Michael K.; Yamazaki, Yusuke; Kashiwaya, Kazuhisa; Nishihara, Terumasa; Kuribayashi, Daisuke; Sawano, Hisaya; Iwami, Yoichi

    2016-07-01

    Japanese groundwater will reach natural levels in a decade, when one tritium measurement will be sufficient to estimate a unique MTT. Using a series of tritium measurements over the next few years with 3-year intervals will enable us to estimate the correct MTT without ambiguity in this period. These unique MTTs will allow estimation of groundwater storage volumes for water resources management during droughts and improvement of numerical model simulations. For example, the groundwater storage ranges between 0.013 and 5.07 km3 with saturated water thickness from 0.2 and 24 m. In summary, we emphasise three important points from our findings: (1) one tritium measurement is already sufficient to estimate MTTs for some Japanese catchments, (2) the hydrogeological settings control the tritium transit times of subsurface groundwater storage during baseflow, and (3) in the future, one tritium measurement will be sufficient to estimate MTTs in most Japanese watersheds.

  11. A study of nitrogen incorporation in pyramidal site-controlled quantum dots

    PubMed Central

    2011-01-01

    We present the results of a study of nitrogen incorporation in metalorganic-vapour-phase epitaxy-grown site-controlled quantum dots (QDs). We report for the first time on a significant incorporation (approximately 0.3%), producing a noteworthy red shift (at least 50 meV) in some of our samples. Depending on the level of nitrogen incorporation/exposure, strong modifications of the optical features are found (variable distribution of the emission homogeneity, fine-structure splitting, few-particle effects). We discuss our results, especially in relation to a specific reproducible sample which has noticeable features: the usual pattern of the excitonic transitions is altered and the fine-structure splitting is suppressed to vanishing values. Distinctively, nitrogen incorporation can be achieved without detriment to the optical quality, as confirmed by narrow linewidths and photon correlation spectroscopy. PMID:22029752

  12. Measurement of tritium with plastic scintillator surface improvement with plasma treatment

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

    Yoshihara, Y.; Furuta, E.; Ohyama, R.I.

    2015-03-15

    Tritium is usually measured by using a liquid scintillation counter. However, liquid scintillator used for measurement will become radioactive waste fluid. To solve this issue, we have developed a method of measuring tritium samples with plasma-treated plastic scintillator (PS)sheets (Plasma method). The radioactive sample is held between 2 PS sheets and the whole is enclosed in a a low-potassium glass vial. With the Plasma method of 2-min plasma treatment, we have obtained measurement efficiency of 48 ± 2 % for 2 min measurement of tritium except for tritiated water. The plasma treatment makes the PS surface rough and hydrophilic whichmore » contributes to improve the contact between tritium and PS. On the other hand, it needed almost 6 hours to obtain constant measurement efficiency. The reason was that the dry-up handling in the vial needed longer time to vaporize H{sub 2}O molecules than in the air. We tried putting silica gel beads into vials to remove H{sub 2}O molecules from PS sheet surface quickly. The silica gel beads worked well and we got constant measurement efficiency within 1-3 hours. Also, we tried using other kinds of PS treated with plasma to obtain higher measurement efficiencies of tritium samples.« less

  13. Chemical forms of tritium on the release from aluminum

    NASA Astrophysics Data System (ADS)

    Yokoyama, A.; Nakashima, M.; Tachikawa, E.

    1981-10-01

    The release-behavior of tritium from aluminum, where tritium has been injected into aluminum samples through 6Li(n,α)T transmutation reaction, has been investigated. When the aluminum samples were dissolved in NaOH/D 2O solutions, a majority of T has appeared as DT but a small fraction as HT, T 2 and DTO. It has been concluded that both HT and T 2 were formed inside of the aluminum. Their formations compete each other and their relative yields are correlated with the impurity content of protium in the sample. The time-profiles of the release rate of tritium on heating the sample have been compared with the results calculated with an appropriate assumption. A little difference between them can be reasonably ascribed to the presence of thin oxide film covering the sample surface.

  14. Radiological Impact of Tritium from Gaseous Effluent Releases at Cook Nuclear Power Plant

    NASA Astrophysics Data System (ADS)

    Young, Joshua Allan

    The purpose of this study was to investigate the washout of tritiated water by snow and rain from gaseous effluent releases at Donald C. Cook Nuclear Power Plant. Primary concepts studied were determination of washout coefficients for rainfall and snowfall; correlations between rainfall and snow fall tritium concentrations with tritium concentrations in the spent fuel pool, reactor cooling systems, and tritium release rates; and calculations of received doses from the process of recapture. The dose calculations are under the assumption of a maximally exposed individual to get the most conservative estimate of the effect that washout of tritiated water has on individuals around the plant site. This study is in addition to previous work that has been conducted at Cook Nuclear Power Plant for several years. The calculated washout coefficients were typically within the range of 1x10-7s -1 to 1x10-5s-1. A strong correlation between tritium concentration within the spent fuel pool and the tritium release rates was determined.

  15. Measurement of tritium in natural water

    NASA Astrophysics Data System (ADS)

    Li, Meifen

    1985-06-01

    A detergent-scintillation liquid mixture applied to measure low specific activity of tritium in natural water was studied. The DYS-1 low level liquid scintillation counter designed and manufactured by our institute was employed. In comparing the Triton X-100 scintillation liquid mixture with the dioxane-based-scintillation liquid, a better formula for Triton X-100 scintillation liquid mixture was determined, the mixture possesses the quality of high water content; high efficiency and low back-ground in measuring tritium in water. Chemiluminescence of the Triton X-100 scintillation liquid mixture can be totally de-excited in short time. It can be employed at ambient temperature 11 28°C. For 20ml sample in quartz vials, counting efficiency is 15% with a background 2.17 cpm, Y=31 TU (t=30 min).

  16. Addressing the Old Water Paradox using tritium

    NASA Astrophysics Data System (ADS)

    Cartwright, Ian; Morgenstern, Uwe

    2017-04-01

    The paradox that much of the water that contributes to streams during high flow events appears to be derived from relatively old stores in catchments has been of interest to hydrogeologists for several decades. It is a common observation that stream chemistry varies less than would be expected if simple dilution of groundwater inflows by event water occurred during storm events. However, it is not clear to what extent this observation reflects displacement of water from the soils or the regolith vs. enhanced discharge of older groundwater into the stream. Here we use tritium in conjunction with major ion and stable isotope tracers to assess the sources of water in high flow events in streams in southeast Australia. The concentrations of most of the major ions and EC values either remained relatively constant during the high flow events or displayed non-systematic variations with respect to flow. Oxygen isotopes do vary systematically during the events, but the magnitude of the variation is <1‰.. By contrast, there is a notable systematic increase in the nitrate concentrations and a decrease in silica concentrations during the events. Tritium activities increased from 1.4 to 1.5 TU to up to 2.4 TU close to the peak in streamflow and then decline over several days to pre-high flow levels. The peak tritium activities in the stream are lower than the tritium activity of the rainfall that generated the high flow events (2.7 to 2.8 TU) but within the range of tritium activities commonly recorded in soil water in southeast Australia (2.0 to 2.6 TU). The combined geochemical data imply that there is significant input from water stores other than groundwater during the high flow events. This is most likely to include a significant component of water displaced from the soils or regolith that typically has a residence time of 1 to 5 years. The major ion geochemistry of this water, especially its nitrate concentrations, is distinct from both groundwater and rainfall

  17. A new bomb-combustion system for tritium extraction.

    PubMed

    Marsh, Richard I; Croudace, Ian W; Warwick, Phillip E; Cooper, Natasha; St-Amant, Nadereh

    2017-01-01

    Quantitative extraction of tritium from a sample matrix is critical to efficient measurement of the low-energy pure beta emitter. Oxidative pyrolysis using a tube furnace (Pyrolyser) has been adopted as an industry standard approach for the liberation of tritium (Warwick et al. in Anal Chim Acta 676:93-102, 2010) however pyrolysis of organic-rich materials can be problematic. Practically, the mass of organic rich sample combusted is typically limited to <1 g to minimise the possibility of incomplete combustion. This can have an impact on both the limit of detection that can be achieved and how representative the subsample is of the bulk material, particularly in the case of heterogeneous soft waste. Raddec International Ltd (Southampton, UK), in conjunction with GAU-Radioanalytical, has developed a new high-capacity oxygen combustion bomb (the Hyperbaric Oxidiser; HBO 2 ) to address this challenge. The system is capable of quantitatively combusting samples of 20-30 g under an excess of oxygen, facilitating rapid extraction of total tritium from a wide range sample types.

  18. Remediation of ground water containing volatile organic compounds and tritium

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

    Shukla, S.N.; Folsom, E.N.

    1994-03-01

    The Trailer 5475 (T-5475) East Taxi Strip Area at Lawrence Livermore National Laboratory (LLNL), Livermore, California was used as a taxi strip by the US Navy to taxi airplanes to the runway from 1942 to 1947. Solvents were used in some unpaved areas adjacent to the East Taxi Strip for cleaning airplanes. From 1953 through 1976, the area was used to store and treat liquid waste. From 1962 to 1976 ponds were constructed and used for evaporation of liquid waste. As a result, the ground water in this area contains volatile organic compounds (VOCs) and tritium. The ground water inmore » this area is also known to contain hexavalent chromium that is probably naturally occurring. Therefore, LLNL has proposed ``pump-and-treat`` technology above grade in a completely closed loop system. The facility will be designed to remove the VOCs and hexavalent chromium, if any, from the ground water, and the treated ground water containing tritium will be reinjected where it will decay naturally in the subsurface. Ground water containing tritium will be reinjected into areas with equal or higher tritium concentrations to comply with California regulations.« less

  19. Simplified method for detecting tritium contamination in plants and soil

    USGS Publications Warehouse

    Andraski, Brian J.; Sandstrom, M.W.; Michel, R.L.; Radyk, J.C.; Stonestrom, David A.; Johnson, M.J.; Mayers, C.J.

    2003-01-01

    Cost-effective methods are needed to identify the presence and distribution of tritium near radioactive waste disposal and other contaminated sites. The objectives of this study were to (i) develop a simplified sample preparation method for determining tritium contamination in plants and (ii) determine if plant data could be used as an indicator of soil contamination. The method entailed collection and solar distillation of plant water from foliage, followed by filtration and adsorption of scintillation-interfering constituents on a graphite-based solid phase extraction (SPE) column. The method was evaluated using samples of creosote bush [Larrea tridentata (Sessé & Moc. ex DC.) Coville], an evergreen shrub, near a radioactive disposal area in the Mojave Desert. Laboratory tests showed that a 2-g SPE column was necessary and sufficient for accurate determination of known tritium concentrations in plant water. Comparisons of tritium concentrations in plant water determined with the solar distillation–SPE method and the standard (and more laborious) toluene-extraction method showed no significant difference between methods. Tritium concentrations in plant water and in water vapor of root-zone soil also showed no significant difference between methods. Thus, the solar distillation–SPE method provides a simple and cost-effective way to identify plant and soil contamination. The method is of sufficient accuracy to facilitate collection of plume-scale data and optimize placement of more sophisticated (and costly) monitoring equipment at contaminated sites. Although work to date has focused on one desert plant, the approach may be transferable to other species and environments after site-specific experiments.

  20. Analysis of Time-Dependent Tritium Breeding Capability of Water Cooled Ceramic Breeder Blanket for CFETR

    NASA Astrophysics Data System (ADS)

    Gao, Fangfang; Zhang, Xiaokang; Pu, Yong; Zhu, Qingjun; Liu, Songlin

    2016-08-01

    Attaining tritium self-sufficiency is an important mission for the Chinese Fusion Engineering Testing Reactor (CFETR) operating on a Deuterium-Tritium (D-T) fuel cycle. It is necessary to study the tritium breeding ratio (TBR) and breeding tritium inventory variation with operation time so as to provide an accurate data for dynamic modeling and analysis of the tritium fuel cycle. A water cooled ceramic breeder (WCCB) blanket is one candidate of blanket concepts for the CFETR. Based on the detailed 3D neutronics model of CFETR with the WCCB blanket, the time-dependent TBR and tritium surplus were evaluated by a coupling calculation of the Monte Carlo N-Particle Transport Code (MCNP) and the fusion activation code FISPACT-2007. The results indicated that the TBR and tritium surplus of the WCCB blanket were a function of operation time and fusion power due to the Li consumption in breeder and material activation. In addition, by comparison with the results calculated by using the 3D neutronics model and employing the transfer factor constant from 1D to 3D, it is noted that 1D analysis leads to an over-estimation for the time-dependent tritium breeding capability when fusion power is larger than 1000 MW. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB108004, 2015GB108002, and 2014GB119000), and by National Natural Science Foundation of China (No. 11175207)

  1. Relative biological effectiveness of tritium for induction of myeloid leukemia in CBA/H mice.

    PubMed

    Johnson, J R; Myers, D K; Jackson, J S; Dunford, D W; Gragtmans, N J; Wyatt, H M; Jones, A R; Percy, D H

    1995-10-01

    To help resolve uncertainties as to the most appropriate weighting factor for tritium beta rays, a large experiment was carried out to measure the relative biological effectiveness (RBE) of tritiated water compared to X rays for the induction of myeloid leukemia in male mice of the CBA/H strain. The study was designed to estimate the lifetime incidence of myeloid leukemia in seven groups of about 750 mice each; radiation exposures were approximately 0, 1, 2 and 3 Gy both for tritiated water and for X rays. The lifetime incidence of leukemia in these mice increased from 0.13% in the control group to 6-8% in groups exposed to higher radiation doses. The results were fitted to various equations relating leukemia incidence to radiation dose, using both the raw data and data corrected for cumulative mouse-days at risk. The calculated RBE values for tritium beta rays compared to X rays ranged from 1.0 +/- 0.5 to 1.3 +/- 0.3. A best estimate of the RBE for this experiment was about 1.2 +/- 0.3. A wR value of 1 would thus appear to be more appropriate than a wR of 2 for tritium beta rays.

  2. Alternate Tritium Production Methods Using A Liquid Lithium Target

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

    Wilson, J.

    For over 60 years, the Savannah River Site’s primary mission has been the production of tritium. From the beginning, the Savannah River National Laboratory (SRNL) has provided the technical foundation to ensure the successful execution of this critical defense mission. SRNL has developed most of the processes used in the tritium mission and provides the research and development necessary to supply this critical component. This project was executed by first developing reactor models that could be used as a neutron source. In parallel to this development calculations were carried out testing the feasibility of accelerator technologies that could also bemore » used for tritium production. Targets were designed with internal moderating material and optimized target was calculated to be capable of 3000 grams using a 1400 MWt sodium fast reactor, 850 grams using a 400 MWt sodium fast reactor, and 100 grams using a 62 MWt reactor, annually.« less

  3. Estimation of recharge rates to the sand and gravel aquifer using environmental tritium, Nantucket Island, Massachusetts

    USGS Publications Warehouse

    Knott, Jayne Fifield; Olimpio, Julio C.

    1986-01-01

    Estimation of the average annual rate of ground-water recharge to sand and gravel aquifers using elevated tritium concentrations in ground water is an alternative to traditional steady-state and water-balance recharge-rate methods. The concept of the tritium tracer method is that the average annual rate of ground-water recharge over a period of time can be calculated from the depth of the peak tritium concentration in the aquifer. Assuming that ground-water flow is vertically downward and that aquifer properties are reasonably homogeneous, and knowing the date of maximum tritium concentration in precipitation and the current depth to the tritium peak from the water table, the average recharge rate can be calculated. The method, which is a direct-measurement technique, was applied at two sites on Nantucket Island, Massachusetts. At site 1, the average annual recharge rate between 1964 and 1983 was 26.1 inches per year, or 68 percent of the average annual precipitation, and the estimated uncertainty is ?15 percent. At site 2, the multilevel water samplers were not constructed deep enough to determine the peak concentration of tritium in ground water. The tritium profile at site 2 resembles the upper part of the tritium profile at site 1 and indicates that the average recharge rate was at least 16 .7 inches per year, or at least 44 percent of the average annual precipitation. The Nantucket tritium recharge rates clearly are higher than rates determined elsewhere in southeastern Massachusetts using the tritium, water-table-fluctuation, and water-balance (Thornthwaite) methods, regardless of the method or the area. Because the recharge potential on Nantucket is so high (runoff is only 2 percent of the total water balance), the tritium recharge rates probably represent the effective upper limit for ground-water recharge in this region. The recharge-rate values used by Guswa and LeBlanc (1985) and LeBlanc (1984) in their ground-water-flow computer models of Cape Cod are

  4. The effects of dual-domain mass transfer on the tritium-helium-3 dating method.

    PubMed

    Neumann, Rebecca B; Labolle, Eric M; Harvey, Charles F

    2008-07-01

    Diffusion of tritiated water (referred to as tritium) and helium-3 between mobile and immobile regions in aquifers (mass transfer) can affect tritium and helium-3 concentrations and hence tritium-helium-3 (3H/3He) ages that are used to estimate aquifer recharge and groundwater residence times. Tritium and helium-3 chromatographically separate during transport because their molecular diffusion coefficients differ. Simulations of tritium and helium-3 transport and diffusive mass transfer along stream tubes show that mass transfer can shift the 3H/3He age of the tritium and helium-3 concentration ([3H + 3He]) peak to dates much younger than the 1963 peak in atmospheric tritium. Furthermore, diffusive mass-transfer can cause the 3H/3He age to become younger downstream along a stream tube, even as the mean water-age must increase. Simulated patterns of [3H + 3He] versus 3H/3He age using a mass transfer model appear consistent with a variety of field data. These results suggest that diffusive mass transfer should be considered, especially when the [3H + 3He] peak is not well defined or appears younger than the atmospheric peak. 3H/3He data provide information about upstream mass-transfer processes that could be used to constrain mass-transfer models; however, uncritical acceptance of 3H/3He dates from aquifers with immobile regions could be misleading.

  5. Synthesis of labeled compounds using recovered tritium from expired beta light sources

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

    Matei, L.; Postolache, C.; Bubueanu, G.

    2008-07-15

    In this paper, the technological procedures for extracting tritium from beta light source are highlighted. The recovered tritium was used in the synthesis of organically labeled compounds and in the preparation of tritiated water (HTO) with high specific activity. Technological procedures for treatment of beta light sources consist of: envelope breaking into evacuated enclosure, the radioactive gaseous mixture pumping and its storage on metallic sodium. The mixtures of T{sub 2} and {sup 3}He were used in the synthesis of tritium labeled steroid hormones, nucleosides analogues and for the preparation of HTO with high radioactivity concentrations. (authors)

  6. Recoil tritium reactions with cyclohexene and methylcyclohexene

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

    Fee, Darrell Clark

    1973-06-01

    A study has been made of the reactions of recoil tritium atoms with cyclohexene with methyl cyclohexene. Principle attention was given to unimolecular decomposition processes following T-for-H substitution.

  7. Implementation of two-phase tritium models for helium bubbles in HCLL breeding blanket modules

    NASA Astrophysics Data System (ADS)

    Fradera, J.; Sedano, L.; Mas de les Valls, E.; Batet, L.

    2011-10-01

    Tritium self-sufficiency requirement of future DT fusion reactors involves large helium production rates in the breeding blankets; this might impact on the conceptual design of diverse fusion power reactor units, such as Liquid Metal (LM) blankets. Low solubility, long residence-times and high production rates create the conditions for Helium nucleation, which could mean effective T sinks in LM channels. A model for helium nano-bubble formation and tritium conjugate transport phenomena in liquid Pb17.5Li and EUROFER is proposed. In a first approximation, it has been considered that He bubbles can be represented as a passive scalar. The nucleation model is based on the classical theory and includes a simplified bubble growth model. The model captures the interaction of tritium with bubbles and tritium diffusion through walls. Results show the influence of helium cavitation on tritium inventory and the importance of simulating the system walls instead of imposing fixed boundary conditions.

  8. Contamination mechanisms of air basin with tritium in venues of underground nuclear explosions at the former Semipalatinsk test site.

    PubMed

    Lyakhova, O N; Lukashenko, S N; Larionova, N V; Tur, Y S

    2012-11-01

    During the period of testing from 1945 to 1962 at the territory of Semipalatinsk test site (STS) within the Degelen Mountains in tunnels, 209 underground nuclear explosions were produced. Many of the tunnels have seasonal water seepage in the form of streams, through which tritium migrates from the underground nuclear explosion (UNE) venues towards the surface. The issue of tritium contamination occupies a special place in the radioactive contamination of the environment. In this paper we assess the level and distribution of tritium in the atmospheric air of ecosystems with water seepage at tunnels № 176 and № 177, located on "Degelen" site. There has been presented general nature of tritium distribution in the atmosphere relative to surface of a watercourse which has been contaminated with tritium. The basic mechanisms were studied for tritium distribution in the air of studied ecosystems, namely, the distribution of tritium in the systems: water-atmosphere, tunnel air-atmosphere, soil water-atmosphere, vegetation-atmosphere. An analytical calculation of tritium concentration in the atmosphere by the concentration of tritium in water has been performed. There has experimentally obtained the dependence for predictive assessment of tritium concentrations in air as a function of tritium concentration in one of the inlet sources such as water, tunnel air, soil water, vegetation, etc.. The paper also describes the general nature of tritium distribution in the air in the area "Degelen". Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Pre-Conceptual Design for Northstar ⁹⁹Mo Process Tritium Removal System

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

    Nobile, Arthur; Reichert, Heidi; Hollis, William Kirk

    2016-01-12

    In this report we describe a preliminary concept for a Tritium Removal System (TRS) to remove tritium that is generated in the ⁹⁹Mo production process. Preliminary calculations have been performed to evaluate an approximate size for the system. The concept described utilizes well-established detritiation technology based on catalytic oxidation of tritium and tritiated hydrocarbons to water in a high temperature (400 °C) reactor and capture of water in a molecular sieve bed. The TRS concept involves use of a single system that would cycle through each of the seven online target systems and remove tritium that has been accumulated aftermore » one week’s run time. The TRS would perform cleanup operations on each target system for a period of approximately 24 hours. This would occur while the system is still online and just prior to target replacement, so tritium levels would at their minimum values for target replacement. In the concept, during normal operation a small fraction (1%) of the helium recirculating in the system would be diverted through the TRS and returned to the flow loop. With this approach sufficient levels of detritiation can be accomplished in a 24 hour period. In the study it was found that because of the need to maintain low oxygen levels in the system (<100 ppm) this increases the size of the catalytic reactor. As a result of this finding, consideration should be given to other methods for removing tritium from the system. Other methods such as catalytic exchange of tritium with an unsaturated organic compound and subsequent trapping on activated carbon or molecular sieve could offer advantages of reducing reactor size and operation at lower reactor temperature. However the most significant advantage of such an approach would be the ability to operate in very low oxygen environments, which would eliminate any concerns for oxidation of the target.« less

  10. [Value of the tritium test for determining the fat content in the body of rats].

    PubMed

    Pisarchuk, K L

    1990-01-01

    An indirect method for estimation of the fat percentage in the animal organism, a tritium test, was studied on laboratory male rats aged 4 and 12 months. Results obtained from the tritium test and direct chemical analysis were compared. With age a mean absolute error of the tritium test increased (from 1 to 8%) as against actual values of the water and fat percentage in the organism obtained by a direct chemical analysis. The data obtained testify to the relative insolvency of the tritium test, as well as the necessity to carry additional investigations in order to obtain adequate data.

  11. Tritium calibration of the LUX dark matter experiment

    NASA Astrophysics Data System (ADS)

    Akerib, D. S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Bradley, A.; Bramante, R.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chapman, J. J.; Chiller, A. A.; Chiller, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; de Viveiros, L.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edwards, B. N.; Faham, C. H.; Fiorucci, S.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Ihm, M.; Jacobsen, R. G.; Ji, W.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lee, C.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Malling, D. C.; Manalaysay, A. G.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Ott, R. A.; Palladino, K. J.; Pangilinan, M.; Pease, E. K.; Phelps, P.; Reichhart, L.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solovov, V. N.; Sorensen, P.; Stephenson, S.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Young, S. K.; Zhang, C.; LUX Collaboration

    2016-04-01

    We present measurements of the electron-recoil (ER) response of the LUX dark matter detector based upon 170 000 highly pure and spatially uniform tritium decays. We reconstruct the tritium energy spectrum using the combined energy model and find good agreement with expectations. We report the average charge and light yields of ER events in liquid xenon at 180 and 105 V /cm and compare the results to the NEST model. We also measure the mean charge recombination fraction and its fluctuations, and we investigate the location and width of the LUX ER band. These results provide input to a reanalysis of the LUX run 3 weakly interacting massive particle search.

  12. The stark effect on the spectrum energy of tritium in first excited state with relativistic condition

    NASA Astrophysics Data System (ADS)

    Prastowo, S. H. B.; Supriadi, B.; Bahri, S.; Ridlo, Z. R.

    2018-04-01

    This research discussed about the correction of Stark Effect on Tritium atoms in the first excited state with relativistic conditions. The approach used to solve this Stark Effect correction was the perturbation theory which was from time independent degenerate perturbation theory to second-order correction. The Stark Effect on the excited state made the spectrum energy polarization of Tritium which was included in the isotope of hydrogen with an electron moving around the nucleus with high velocity. Hence, the relativistic correction affected the spectrum energy shift. Tritium was a radioactive material having half-time 12,3 years and relatively safe. The Tritium application was a material for the manufacture of nuclear battery. The most effective external electric field that should give to Tritium was 108 V/mith the total correction energy that was 0,97398557 × 10-21 Joule. Therefore, its effect reduced the binding energy between electron and nucleus, and increased the power of Tritium Betavoltaics Battery.

  13. Tritium processing for the European test blanket systems: current status of the design and development strategy

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

    Ricapito, I.; Calderoni, P.; Poitevin, Y.

    2015-03-15

    Tritium processing technologies of the two European Test Blanket Systems (TBS), HCLL (Helium Cooled Lithium Lead) and HCPB (Helium Cooled Pebble Bed), play an essential role in meeting the main objectives of the TBS experimental campaign in ITER. The compliancy with the ITER interface requirements, in terms of space availability, service fluids, limits on tritium release, constraints on maintenance, is driving the design of the TBS tritium processing systems. Other requirements come from the characteristics of the relevant test blanket module and the scientific programme that has to be developed and implemented. This paper identifies the main requirements for themore » design of the TBS tritium systems and equipment and, at the same time, provides an updated overview on the current design status, mainly focusing onto the tritium extractor from Pb-16Li and TBS tritium accountancy. Considerations are also given on the possible extrapolation to DEMO breeding blanket. (authors)« less

  14. Tritium concentrations in flow from selected springs that discharge to the Snake River, Twin Falls-Hagerman area, Idaho

    USGS Publications Warehouse

    Mann, L.J.

    1989-01-01

    Concern has been expressed that some of the approximately 30,900 curies of tritium disposed to the Snake River Plain aquifer from 1952 to 1988 at the INEL (Idaho National Engineering Laboratory) have migrated to springs discharging to the Snake River in the Twin Falls-Hagerman area. To document tritium concentrations in springflow, 17 springs were sampled in November 1988 and 19 springs were sampled in March 1989. Tritium concentrations were less than the minimum detectable concentration of 0.5 pCi/mL (picocuries/mL) in November 1988 and less than the minimum detectable concentration of 0.2 pCi/mL in March 1989; the minimum detectable concentration was smaller in March 1989 owing to a longer counting time in the liquid scintillation system. The maximum contaminant level of tritium in drinking water as established by the U.S. Environmental Protection Agency is 20 pCi/mL. U.S. Environmental Protection Agency sample analyses indicate that the tritium concentration has decreased in the Snake River near Buhl since the 1970's. In 1974-79, tritium concentrations were less than 0.3 +/-0.2 pCi/mL in 3 of 20 samples; in 1983-88, 17 of 23 samples contained less than 0.3 +/-0.2 pCi/mL of tritium; the minimum detectable concentration is 0.2 pCi/mL. On the basis of decreasing tritium concentrations in the Snake River, their correlation to cessation of atmospheric weapons tests tritium concentrations in springflow less than the minimum detectable concentration, and the distribution of tritium in groundwater at the INEL, aqueous disposal of tritium at the INEL has had no measurable effect on tritium concentrations in springflow from the Snake River Plain aquifer and in the Snake River near Buhl. (USGS)

  15. Synthesis of carrier-free tritium-labeled queen bee pheromone

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

    Webster, F.X.; Prestwich, G.D.

    A short synthesis of (4,5-/sup 3/H/sub 2/) (E)-9-oxo-2-decenoic acid (ODA), a high-specific-activity tritium-containing isotopomer of the queen bee pheromone, is described. Catalytic tritiation of the ketal of ethyl 9-oxo-4-decenoate introduces tritium into two positions, one of which is completely unactivated. Subsequent transformation by selenation, oxidation, and hydrolysis affords the labeled 9-ODA at >60 Ci/mmol. The material is suitable for biochemical studies of binding and catabolism in ovarian, antennal, and other target tissues.

  16. Tritium assay of Li sub 2 O pellets in the LBM/LOTUS experiments

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

    Quanci, J.; Azam, S.; Bertone, P.

    1986-01-01

    One of the objectives of the Lithium Blanket Module (LBM) program is to test the ability of advanced neutronics codes to model the tritium breeding characteristics of a fusion blanket exposed to a toroidal fusion neutron source. The LBM consists of over 20,000 cylindrical lithium oxide pellets and numerous diagnostic pellets and wafers. The LBM has been irradiated at the Ecole Polytechnique Federale de Lausanne (EPFL) LOTUS facility with a Haefely sealed neutron generator that gives a point deuterium-tritium neutron source up to 5 {times} 10{sup 12} 14-MeV n/s. Both Princeton Plasma Physics Laboratory (PPL) and EPFL assayed the tritiummore » bred at various positions in the LBM. EPFL employed a dissolution technique while PPL recovered the tritium by a thermal extraction method. EPFL uses 0.38-g, 75% TD, lithium oxide diagnostic wafers to evaluate the tritium bred in the LBM. PPPL employs a thermal extraction method to determine the tritium bred in lithium oxide samples. In the initial experiments, diagnostic pellets and wafers were placed at five locations in the LBM central removable test rod at distances of 3, 9, 21, 36, and 48 cm from the front face of the module. The two sets of data for the tritium bred in the LBM along its centerline as a function of distance from the front face of the module were compared with each other, and with the predictions of two-dimensional neutronics codes. 1 ref.« less

  17. Incorporating engine health monitoring capability into the SSME Block II controller

    NASA Astrophysics Data System (ADS)

    Clarke, James W.; Copa, Roderick J.

    An account is given of the architecture of the SSME's Block II controller's architecture, its incorporation of smart input electronics (SIE), and the potential benefits of this technology in SSME health-monitoring capabilities. SIE allows the Block II controller to conduct its control functions while simultaneously furnishing the computational capabilities and sensor input interface for any newly defined health-monitoring functions. It is expected that the SIE technology may be directly transferred to any follow-on engine design.

  18. A simple polymer electrolyte membrane system for enrichment of low-level tritium (3H) in environmental water samples.

    PubMed

    Wassenaar, Leonard I; Han, Liang-Feng; Schiefer, Thomas; Kainz, Gustav; Araguas-Araguas, Luis; Aggarwal, Pradeep K

    2018-06-01

    Tritium ( 3 H) is an essential tracer of the Earth's water cycle; yet widespread adoption of tritium in hydrologic studies remains a challenge because of analytical barriers to quantification and detection of 3 H by electrolytic pre-concentration. Here, we propose a simple tritium electrolytic enrichment system based on the use of solid polymer electrolyte membranes (PEMs) that can be used to enrich 3 H in 250-3000 mL environmental water samples to a 10-mL final volume. The IAEA PEM- 3 H system reported here can produce high enrichment factors (>70-fold) and, importantly, removes some of the deterrents to conventional 3 H enrichments methods, including the use of toxic electrolysis and neutralization chemicals, spike standards, a complex electrolysis apparatus that requires extensive cooling and temperature controls, and improves precision by eliminating the need for tracking recovery gravimetrics. Preliminary results with varying operating conditions show 3 H enrichments to 70-fold and higher are feasible, spanning a wide range of tritium activities from 5 to 150 TU with a precision of ∼4.5 %. Further work is needed to quantify inter-sample memory and to establish lower 3 H detection limits. The IAEA PEM- 3 H system is open source, with 3-D CAD and design files made freely available for adoption and improvement by others.

  19. Measurement of uptake and release of tritium by tungsten

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

    Nakayama, M.; Torikai, Y.; Saito, M.

    2015-03-15

    Tungsten is currently contemplated as plasma facing material for the divertor of future fusion machines. In this paper the uptake of tritium by tungsten and its release behavior have been investigated. Tungsten samples have been annealed at various temperatures and loaded at also different temperatures with deuterium containing 7.2 % tritium at a pressure of 1.2 kPa. A specific system was designed to assess the release of tritiated water and molecular tritium by the samples. Due to the rather low solubility of hydrogen isotopes in tungsten it is particularly important to be aware of the presence of hydrogen traps ormore » thin oxide films. As shown in this work, traps or oxide films may affect the retention capability of tungsten and lead to significantly modified release properties. It became clear that there were capture sites that had different thermal stability and different capture intensity in tungsten after polishing, or oxide films that were grown on the surface of tungsten and had barrier effects.« less

  20. Tritium internal dose estimation from measurements with liquid scintillators.

    PubMed

    Pántya, A; Dálnoki, Á; Imre, A R; Zagyvai, P; Pázmándi, T

    2018-07-01

    Tritium may exist in several chemical and physical forms in workplaces, common occurrences are in vapor or liquid form (as tritiated water) and in organic form (e.g. thymidine) which can get into the body by inhalation or by ingestion. For internal dose assessment it is usually assumed that urine samples for tritium analysis are obtained after the tritium concentration inside the body has reached equilibrium following intake. Comparison was carried out for two types of vials, two efficiency calculation methods and two available liquid scintillation devices to highlight the errors of the measurements. The results were used for dose estimation with MONDAL-3 software. It has been shown that concerning the accuracy of the final internal dose assessment, the uncertainties of the assumptions used in the dose assessment (for example the date and route of intake, the physical and chemical form) can be more influential than the errors of the measured data. Therefore, the improvement of the experimental accuracy alone is not the proper way to improve the accuracy of the internal dose estimation. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Incorporating Quality Control Information in the Sensor Web

    NASA Astrophysics Data System (ADS)

    Devaraju, Anusuriya; Kunkel, Ralf; Bogena, Heye

    2013-04-01

    The rapid development of sensing technologies had led to the creation of large amounts of heterogeneous environmental observations. The Sensor Web provides a wider access to sensors and observations via common protocols and specifications. Observations typically go through several levels of quality control, and aggregation before they are made available to end-users. Raw data are usually inspected, and related quality flags are assigned. Data are gap-filled, and errors are removed. New data series may also be derived from one or more corrected data sets. Until now, it is unclear how these kinds of information can be captured in the Sensor Web Enablement (SWE) framework. Apart from the quality measures (e.g., accuracy, precision, tolerance, or confidence), the levels of observational series, the changes applied, and the methods involved must be specified. It is important that this kind of quality control information is well described and communicated to end-users to allow for a better usage and interpretation of data products. In this paper, we describe how quality control information can be incorporated into the SWE framework. Concerning this, first, we introduce the TERENO (TERrestrial ENvironmental Observatories), an initiative funded by the large research infrastructure program of the Helmholtz Association in Germany. The main goal of the initiative is to facilitate the study of long-term effects of climate and land use changes. The TERENO Online Data RepOsitORry (TEODOOR) is a software infrastructure that supports acquisition, provision, and management of observations within TERENO via SWE specifications and several other OGC web services. Next, we specify changes made to the existing observational data model to incorporate quality control information. Here, we describe the underlying TERENO data policy in terms of provision and maintenance issues. We present data levels, and their implementation within TEODOOR. The data levels are adapted from those used by

  2. Fabrication and tritium release property of Li2TiO3-Li4SiO4 biphasic ceramics

    NASA Astrophysics Data System (ADS)

    Yang, Mao; Ran, Guangming; Wang, Hailiang; Dang, Chen; Huang, Zhangyi; Chen, Xiaojun; Lu, Tiecheng; Xiao, Chengjian

    2018-05-01

    Li2TiO3-Li4SiO4 biphasic ceramic pebbles have been developed as an advanced tritium breeder due to the potential to combine the advantages of both Li2TiO3 and Li4SiO4. Wet method was developed for the pebble fabrication and Li2TiO3-Li4SiO4 biphasic ceramic pebbles were successfully prepared by wet method using the powders synthesized by hydrothermal method. The tritium release properties of the Li2TiO3-Li4SiO4 biphasic ceramic pebbles were evaluated. The biphasic pebbles exhibited good tritium release property at low temperatures and the tritium release temperature was around 470 °C. Because of the isotope exchange reaction between H2 and tritium, the addition of 0.1%H2 to purge gas He could significantly enhance the tritium gas release and the fraction of molecular form of tritium increased from 28% to 55%. The results indicate that the Li2TiO3-Li4SiO4 biphasic ceramic pebbles fabricated by wet method exhibit good tritium release property and hold promising potential as advanced breeder pebbles.

  3. Analysis of a global database containing tritium in precipitation

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

    Buckley, R. L.; Rabun, R. L.; Heath, M.

    The International Atomic Energy Agency (IAEA) directed the collection of tritium in water samples from the mid-1950s to 2009. The Global Network of Isotopes in Precipitation (GNIP) data examined the airborne movement of isotope releases to the environment, with an objective of collecting spatial data on the isotope content of precipitation across the globe. The initial motivation was to monitor atmospheric thermonuclear test fallout through tritium, deuterium, and oxygen isotope concentrations, but after the 1970s the focus changed to being an observation network of stable hydrogen and oxygen isotope data for hydrologic studies. The GNIP database provides a wealth ofmore » tritium data collections over a long period of time. The work performed here primarily examined data features in the past 30 years (after much of the effects of above-ground nuclear testing in the late 1950s to early 1960s decayed away), revealing potentially unknown tritium sources. The available data at GNIP were reorganized to allow for evaluation of trends in the data both temporally and spatially. Several interesting cases were revealed, including relatively high measured concentrations in the Atlantic and Indian Oceans, Russia, Norway, as well as an increase in background concentration at a collector in South Korea after 2004. Recent data from stations in the southeastern United States nearest to the Savannah River Site do not indicate any high values. Meteorological impacts have not been considered in this study. Further research to assess the likely source location of interesting cases using transport simulations and/or literature searches is warranted.« less

  4. Tritium calibration of the LUX dark matter experiment

    DOE PAGES

    Akerib, D. S.

    2016-04-20

    Here, we present measurements of the electron-recoil (ER) response of the LUX dark matter detector based upon 170,000 highly pure and spatially uniform tritium decays. We reconstruct the tritium energy spectrum using the combined energy model and find good agreement with expectations. We report the average charge and light yields of ER events in liquid xenon at 180 and 105 V/cm and compare the results to the NEST model. We also measure the mean charge recombination fraction and its fluctuations, and we investigate the location and width of the LUX ER band. These results provide input to a reanalysis ofmore » the LUX run 3 weakly interacting massive particle search.« less

  5. Residence times in river basins as determined by analysis of long-term tritium records

    USGS Publications Warehouse

    Michel, R.L.

    1992-01-01

    The US Geological Survey has maintained a network of stations to collect samples for the measurement of tritium concentrations in precipitation and streamflow since the early 1960s. Tritium data from outflow waters of river basins draining 4500-75000 km2 are used to determine average residence times of water within the basins. The basins studied are the Colorado River above Cisco, Utah; the Kissimmee River above Lake Okeechobee, Florida; the Mississippi River above Anoka, Minnesota; the Neuse River above Streets Ferry Bridge near Vanceboro, North Carolina; the Potomac River above Point of Rocks, Maryland; the Sacramento River above Sacramento, California; the Susquehanna River above Harrisburg, Pennsylvania. The basins are modeled with the assumption that the outflow in the river comes from two sources-prompt (within-year) runoff from precipitation, and flow from the long-term reservoirs of the basin. Tritium concentration in the outflow water of the basin is dependent on three factors: (1) tritium concentration in runoff from the long-term reservoir, which depends on the residence time for the reservoir and historical tritium concentrations in precipitation; (2) tritium concentrations in precipitation (the within-year runoff component); (3) relative contributions of flow from the long-term and within-year components. Predicted tritium concentrations for the outflow water in the river basins were calculated for different residence times and for different relative contributions from the two reservoirs. A box model was used to calculate tritium concentrations in the long-term reservoir. Calculated values of outflow tritium concentrations for the basin were regressed against the measured data to obtain a slope as close as possible to 1. These regressions assumed an intercept of zero and were carried out for different values of residence time and reservoir contribution to maximize the fit of modeled versus actual data for all the above rivers. The final slopes of the

  6. A tritium activity monitor for the KATRIN Experiment

    NASA Astrophysics Data System (ADS)

    Schmitt, Udo

    2008-06-01

    The KArlsruhe TRItium Neutrino experiment KATRIN is designed to measure the absolute neutrino mass scale by analyzing the endpoint region of the tritium beta-decay spectrum with a sensitivity of 0.2 eV/c2 (90 % C.L.). A high-luminous windowless gaseous tritium source with an activity of 1.7 · 1011 Bq will produce the decay electrons, their energy spectrum will be analyzed by a combination of two electrostatic retarding spectrometers with magnetic adiabatic collimation (MAC-E-filter). Fluctuations of the source column density and inelastic scattering processes within the source affect the energy distribution of the decay electrons. Hence, a precise and continuous monitoring of the source activity is necessary to correct the data taken by the main detector. A prototype of the beam monitor detector, based on a silicon drift diode, has been developed to measure an expected counting rate in the range of 106/(s · mm2). The detector element shall be moveable across the complete beam in a magnetic field of 0.8 T, resulting in a beam diameter of 20 cm. A precise sensor positioning device has been designed and built to be compatible with the primary beamline vacuum of 10-11 mbar.

  7. Tritium plume dynamics in the shallow unsaturated zone in an arid environment

    USGS Publications Warehouse

    Maples, S.R.; Andraski, Brian J.; Stonestrom, David A.; Cooper, C.A.; Pohll, G.; Michel, R.L.

    2014-01-01

    The spatiotemporal variability of a tritium plume in the shallow unsaturated zone and the mechanisms controlling its transport were evaluated during a 10-yr study. Plume movement was minimal and its mass declined by 68%. Upward-directed diffusive-vapor tritium fluxes and radioactive decay accounted for most of the observed plume-mass declines.Effective isolation of tritium (3H) and other contaminants at waste-burial facilities requires improved understanding of transport processes and pathways. Previous studies documented an anomalously widespread (i.e., theoretically unexpected) distribution of 3H (>400 m from burial trenches) in a dry, sub-root-zone gravelly layer (1–2-m depth) adjacent to a low-level radioactive waste (LLRW) burial facility in the Amargosa Desert, Nevada, that closed in 1992. The objectives of this study were to: (i) characterize long-term, spatiotemporal variability of 3H plumes; and (ii) quantify the processes controlling 3H behavior in the sub-root-zone gravelly layer beneath native vegetation adjacent to the facility. Geostatistical methods, spatial moment analyses, and mass flux calculations were applied to a spatiotemporally comprehensive, 10-yr data set (2001–2011). Results showed minimal bulk-plume advancement during the study period and limited Fickian spreading of mass. Observed spreading rates were generally consistent with theoretical vapor-phase dispersion. The plume mass diminished more rapidly than would be expected from radioactive decay alone, indicating net efflux from the plume. Estimates of upward 3H efflux via diffusive-vapor movement were >10× greater than by dispersive-vapor or total-liquid movement. Total vertical fluxes were >20× greater than lateral diffusive-vapor fluxes, highlighting the importance of upward migration toward the land surface. Mass-balance calculations showed that radioactive decay and upward diffusive-vapor fluxes contributed the majority of plume loss. Results indicate that plume losses

  8. Thermal Release of 3He from Tritium Aged LaNi 4.25Al 0.75 Hydride

    DOE PAGES

    Staack, Gregory C.; Crowder, Mark L.; Klein, James E.

    2015-02-01

    Recently, the demand for He-3 has increased dramatically due to widespread use in nuclear nonproliferation, cryogenic, and medical applications. Essentially all of the world’s supply of He-3 is created by the radiolytic decay of tritium. The Savannah River Site Tritium Facilities (SRS-TF) utilizes LANA.75 in the tritium process to store hydrogen isotopes. The vast majority of He-3 “born” from tritium stored in LANA.75 is trapped in the hydride metal matrix. The SRS-TF has multiple LANA.75 tritium storage beds that have been retired from service with significant quantities of He-3 trapped in the metal. To support He-3 recovery, the Savannah Rivermore » National Laboratory (SRNL) conducted thermogravimetric analysis coupled with mass spectrometry (TGA-MS) on a tritium aged LANA.75 sample. TGA-MS testing was performed in an argon environment. Prior to testing, the sample was isotopically exchanged with deuterium to reduce residual tritium and passivated with air to alleviate pyrophoric concerns associated with handling the material outside of an inert glovebox. Analyses indicated that gas release from this sample was bimodal, with peaks near 220 and 490°C. The first peak consisted of both He-3 and residual hydrogen isotopes, the second was primarily He-3. The bulk of the gas was released by 600 °C« less

  9. Continuous production of tritium in an isotope-production reactor with a separate circulation system

    DOEpatents

    Cawley, W.E.; Omberg, R.P.

    1982-08-19

    A method is described for producing tritium in a fast breeder reactor cooled with liquid metal. Lithium is allowed to flow through the reactor in separate loops in order to facilitate the production and removal of tritium.

  10. Capture of Tritium Released from Cladding in the Zirconium Recycle Process

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

    Spencer, Barry B.; Walker, T. B.; Bruffey, S. H.

    2016-08-31

    Zirconium may be recovered from the Zircaloy® cladding of used nuclear fuel (UNF) for recycle or to reduce the quantities of high-level waste destined for a geologic repository. Recovery of zirconium using a chlorination process is currently under development at the Oak Ridge National Laboratory. The approach is to treat the cladding with chlorine gas to convert the zirconium in the alloy (~98 wt % of the alloy mass) to zirconium tetrachloride. A significant fraction of the tritium (0–96%) produced in nuclear fuel during irradiation may be found in zirconium-based cladding and could be released from the cladding when themore » solid matrix is destroyed by the chlorination reaction. To prevent uncontrolled release of radioactive tritium to other parts of the plant or to the environment, a method to recover the tritium may be required. The focus of this effort was to (1) identify potential methods for the recovery of tritium from the off-gas of the zirconium recycle process, (2) perform scoping tests on selected recovery methods using nonradioactive gas simulants, and (3) select a process design appropriate for testing on radioactive gas streams generated by the engineering-scale zirconium recycle demonstrations on radioactive used cladding.« less

  11. Cytogenetic damage analysis in mice chronically exposed to low-dose internal tritium beta-particle radiation.

    PubMed

    Roch-Lefèvre, Sandrine; Grégoire, Eric; Martin-Bodiot, Cécile; Flegal, Matthew; Fréneau, Amélie; Blimkie, Melinda; Bannister, Laura; Wyatt, Heather; Barquinero, Joan-Francesc; Roy, Laurence; Benadjaoud, Mohamed; Priest, Nick; Jourdain, Jean-René; Klokov, Dmitry

    2018-06-08

    The aim of this study was to carry out a comprehensive examination of potential genotoxic effects of low doses of tritium delivered chronically to mice and to compare these effects to the ones resulting from equivalent doses of gamma-irradiation. Mice were chronically exposed for one or eight months to either tritiated water (HTO) or organically bound tritium (OBT) in drinking water at concentrations of 10 kBq/L, 1 MBq/L or 20 MBq/L. Dose rates of internal β-particle resulting from such tritium treatments were calculated and matching external gamma-exposures were carried out. We measured cytogenetic damage in bone marrow and in peripheral blood lymphocytes (PBLs) and the cumulative tritium doses (0.009 - 181 mGy) were used to evaluate the dose-response of OBT in PBLs, as well as its relative biological effectiveness (RBE). Neither tritium, nor gamma exposures produced genotoxic effects in bone marrow. However, significant increases in chromosome damage rates in PBLs were found as a result of chronic OBT exposures at 1 and 20 M Bq/L, but not at 10 kBq/L. When compared to an external acute gamma-exposure ex vivo , the RBE of OBT for chromosome aberrations induction was evaluated to be significantly higher than 1 at cumulative tritium doses below 10 mGy. Although found non-existent at 10 kBq/L (the WHO limit), the genotoxic potential of low doses of tritium (>10 kBq/L), mainly OBT, may be higher than currently assumed.

  12. TFTR neutral beam control and monitoring for DT operations

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

    O`Connor, T.; Kamperschroer, J.; Chu, J.

    1995-12-31

    Record fusion power output has recently been obtained in TFTR with the injection of deuterium and tritium neutral beams. This significant achievement was due in part to the controls, software, and data processing capabilities added to the neutral beam system for DT operations. Chief among these improvements was the addition of SUN workstations and large dynamic data storage to the existing Central Instrumentation Control and Data Acquisition (CICADA) system. Essentially instantaneous look back over the recent shot history has been provided for most beam waveforms and analysis results. Gas regulation controls allowing remote switchover between deuterium and tritium were alsomore » added. With these tools, comparison of the waveforms and data of deuterium and tritium for four test conditioning pulses quickly produced reliable tritium setpoints. Thereafter, all beam conditioning was performed with deuterium, thus saving the tritium supply for the important DT injection shots. The lookback capability also led to modifications of the gas system to improve reliability and to control ceramic valve leakage by backbiasing. Other features added to improve the reliability and availability of DT neutral beam operations included master beamline controls and displays, a beamline thermocouple interlock system, a peak thermocouple display, automatic gas inventory and cryo panel gas loading monitoring, beam notching controls, a display of beam/plasma interlocks, and a feedback system to control beam power based on plasma conditions.« less

  13. Estimating subsurface water volumes and transit times in Hokkaido river catchments, Japan, using high-accuracy tritium analysis

    NASA Astrophysics Data System (ADS)

    Gusyev, Maksym; Yamazaki, Yusuke; Morgenstern, Uwe; Stewart, Mike; Kashiwaya, Kazuhisa; Hirai, Yasuyuki; Kuribayashi, Daisuke; Sawano, Hisaya

    2015-04-01

    The goal of this study is to estimate subsurface water transit times and volumes in headwater catchments of Hokkaido, Japan, using the New Zealand high-accuracy tritium analysis technique. Transit time provides insights into the subsurface water storage and therefore provides a robust and quick approach to quantifying the subsurface groundwater volume. Our method is based on tritium measurements in river water. Tritium is a component of meteoric water, decays with a half-life of 12.32 years, and is inert in the subsurface after the water enters the groundwater system. Therefore, tritium is ideally suited for characterization of the catchment's responses and can provide information on mean water transit times up to 200 years. Only in recent years has it become possible to use tritium for dating of stream and river water, due to the fading impact of the bomb-tritium from thermo-nuclear weapons testing, and due to improved measurement accuracy for the extremely low natural tritium concentrations. Transit time of the water discharge is one of the most crucial parameters for understanding the response of catchments and estimating subsurface water volume. While many tritium transit time studies have been conducted in New Zealand, only a limited number of tritium studies have been conducted in Japan. In addition, the meteorological, orographic and geological conditions of Hokkaido Island are similar to those in parts of New Zealand, allowing for comparison between these regions. In 2014, three field trips were conducted in Hokkaido in June, July and October to sample river water at river gauging stations operated by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT). These stations have altitudes between 36 m and 860 m MSL and drainage areas between 45 and 377 km2. Each sampled point is located upstream of MLIT dams, with hourly measurements of precipitation and river water levels enabling us to distinguish between the snow melt and baseflow contributions

  14. Apparatus for monitoring tritium in tritium-contaminating environments using a modified Kanne chamber

    DOEpatents

    Anderson, D.F.

    1981-01-27

    A conventional Kanne tritium monitor has been redesigned to reduce its sensitivity to such contaminants as tritiated water vapor and tritiated oil. The high voltage electrode has been replaced by a wire cylinder and the collector electrode has been reduced in diameter. The area sensitive to contamination has thereby been reduced by about a factor of forty while the overall apparatus sensitivity and operation has not been affected. The design allows for in situ decontamination of the chambers, if necessary.

  15. Apparatus for monitoring tritium in tritium contaminating environments using a modified Kanne chamber

    DOEpatents

    Anderson, David F.

    1984-01-01

    A conventional Kanne tritium monitor has been redesigned to reduce its sensitivity to such contaminants as tritiated water vapor and tritiated oil. The high voltage electrode has been replaced by a wire cylinder and the collector electrode has been reduced in diameter. The area sensitive to contamination has thereby been reduced by about a factor of forty while the overall apparatus sensitivity and operation has not been affected. The design allows for in situ decontamination of the chambers, if necessary.

  16. Elastic Electron Scattering from Tritium and Helium-3

    DOE R&D Accomplishments Database

    Collard, H.; Hofstadter, R.; Hughes, E. B.; Johansson, A.; Yearian, M. R.; Day, R. B.; Wagner, R. T.

    1964-10-01

    The mirror nuclei of tritium and helium-3 have been studied by the method of elastic electron scattering. Absolute cross sections have been measured for incident electron energies in the range 110 - 690 MeV at scattering angles lying between 40 degrees and 135 degrees in this energy range. The data have been interpreted in a straightforward manner and form factors are given for the distributions of charge and magnetic moment in the two nuclei over a range of four-momentum transfer squared 1.0 - 8.0 F{sup -2}. Model-independent radii of the charge and magnetic moment distributions are given and an attempt is made to deduce form factors describing the spatial distribution of the protons in tritium and helium-3.

  17. Use of system code to estimate equilibrium tritium inventory in fusion DT machines, such as ARIES-AT and components testing facilities

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

    C.P.C. Wong; B. Merrill

    2014-10-01

    ITER is under construction and will begin operation in 2020. This is the first 500 MWfusion class DT device, and since it is not going to breed tritium, it will consume most of the limited supply of tritium resources in the world. Yet, in parallel, DT fusion nuclear component testing machines will be needed to provide technical data for the design of DEMO. It becomes necessary to estimate the tritium burn-up fraction and corresponding initial tritium inventory and the doubling time of these machines for the planning of future supply and utilization of tritium. With the use of a systemmore » code, tritium burn-up fraction and initial tritium inventory for steady state DT machines can be estimated. Estimated tritium burn-up fractions of FNSF-AT, CFETR-R and ARIES-AT are in the range of 1–2.8%. Corresponding total equilibrium tritium inventories of the plasma flow and tritium processing system, and with the DCLL blanket option are 7.6 kg, 6.1 kg, and 5.2 kg for ARIES-AT, CFETR-R and FNSF-AT, respectively.« less

  18. Modeling tritium transport through a deep unsaturated zone in an arid environment

    USGS Publications Warehouse

    Mayers, C.J.; Andraski, Brian J.; Cooper, C.A.; Wheatcraft, S.W.; Stonestrom, David A.; Michel, R.L.

    2005-01-01

    Understanding transport of tritium (3H) in unsaturated zones is critical to evaluating options for waste isolation. Tritium typically is a large component of low-level radioactive waste (LLRW). Studies at the U.S. Geological Survey's Amargosa Desert Research Site (ADRS) in Nevada investigate 3H transport from a closed LLRW facility. Two boreholes are 100 and 160 m from the nearest waste trench and extend to the water table at 110 m. Soil-water vapor samples from the deep boreholes show elevated levels of 3H at all depths. The objectives of this study were to (i) test source thermal and gas-advection mechanisms driving 3H transport and (ii) evaluate model sensitivity to these mechanisms and to selected physical and hydraulic properties including porosity, tortuosity, and anisotropy. A two-dimensional numerical model incorporated a non-isothermal, heterogeneous domain of the unsaturated zone and instantaneous isotopic equilibrium. The TOUGH2 code was used; however, it required modification to account for temperature dependence of both the Henry's law equilibrium constant and isotopic fractionation with respect to tritiated water. Increases in source temperature, pressure, and porosity enhanced 3H migration, but failed to match measured 3H distributions. All anisotropic simulations with a source pressure component resembled, in shape, the upper portion of the 3H distribution of the nearest borehole. Isotopic equilibrium limited migration of 3H, while effects of radioactive decay were negligible. A 500 Pa pressure increase above ambient pressure in conjunction with a high degree of anisotropy (1:100) was necessary for simulated 3H transport to reach the nearest borehole.

  19. Apparatus to recover tritium from tritiated molecules

    DOEpatents

    Swansiger, William A.

    1988-01-01

    An apparatus for recovering tritium from tritiated compounds is provided, including a preheater for heating tritiated water and other co-injected tritiated compounds to temperatures of about 600.degree. C. and a reactor charged with a mixture of uranium and uranium dioxide for receiving the preheated mixture. The reactor vessel is preferably stainless steel of sufficient mass so as to function as a heat sink preventing the reactor side walls from approaching high temperatures. A disposable copper liner extends between the reaction chamber and stainless steel outer vessel to prevent alloying of the uranium with the outer vessel. The uranium dioxide functions as an insulating material and heat sink preventing the reactor side walls from attaining reaction temperatures to thereby minimize tritium permeation rates. The uranium dioxide also functions as a diluent to allow for volumetric expansion of the uranium as it is converted to uranium dioxide.

  20. Tritium as tracer of groundwater pollution extension: case study of Andralanitra landfill site, Antananarivo-Madagascar

    NASA Astrophysics Data System (ADS)

    Ramaroson, Voahirana; Rakotomalala, Christian Ulrich; Rajaobelison, Joel; Fareze, Lahimamy Paul; Razafitsalama, Falintsoa A.; Rasolofonirina, Mamiseheno

    2018-05-01

    This study aims to understand the extension of groundwater pollution downstream of a landfill, Andralanitra-Antananarivo-Madagascar. Twenty-one samples, composed of dug well waters, spring waters, river, and lake, were measured in stable isotopes ( δ 2H, δ 18O) and tritium. Results showed that only two dug well waters, collected at the immediate vicinity of the landfill, have high tritium activities (22.82 TU and 10.43 TU), probably of artificial origin. Both upstream and further downstream of the landfill, tritium activities represent natural source, with values varying from 0.17 TU to 1.46 TU upstream and from 0.88 TU to 1.88 TU further downstream. Stable isotope data suggest that recharge occurs through infiltration of slightly evaporated rainfall. Using the radioactive decay equation, the calculated tracer ages related to two recent ground water samples collected down gradient of the landfill lay between [8-15] years and [4-7] years, taking into account the uncertainty of tritium measurements. For the calculation, a value of 2.36 TU was taken as A o. The latter was estimated based on similarity between stable isotope compositions of nearby spring and dug well waters as well as tritium activities of the local precipitation. Calculation of the tritium activities from the contaminated water point having 22.82 TU to further downstream using the calculated tracer ages showed values of one order of magnitude higher than the measured values. The absence of hydrological connection from the contaminated water point to further downstream the landfill would explain the lower tritium activities measured. Groundwater pollution seems to be limited to the closest proximity of the landfill.

  1. Measurement of helium isotopes in soil gas as an indicator of tritium groundwater contamination.

    PubMed

    Olsen, Khris B; Dresel, P Evan; Evans, John C; McMahon, William J; Poreda, Robert

    2006-05-01

    The focus of this study was to define the shape and extent of tritium groundwater contamination emanating from a legacy burial ground and to identify vadose zone sources of tritium using helium isotopes (3He and 4He) in soil gas. Helium isotopes were measured in soil-gas samples collected from 70 sampling points around the perimeter and downgradient of a burial ground that contains buried radioactive solid waste. The soil-gas samples were analyzed for helium isotopes using rare gas mass spectrometry. 3He/4He ratios, reported as normalized to the air ratio (RA), were used to locate the tritium groundwater plume emanating from the burial ground. The 3He (excess) suggested that the general location of the tritium source is within the burial ground. This study clearly demonstrated the efficacy of the 3He method for application to similar sites elsewhere within the DOE weapons complex.

  2. Concentration and removal of tritium and/or deuterium from water contaminated with tritium and/or deuterium

    DOEpatents

    Meyer, Thomas J.; Narula, Poonam M.

    2001-01-01

    Concentration of tritium and/or deuterium that is a contaminant in H.sub.2 O, followed by separation of the concentrate from the H.sub.2 O. Employed are certain metal oxo complexes, preferably with a metal from Group VIII. For instance, [Ru.sup.IV (2,2',6',2"-terpyridine)(2,2'-bipyridine)(O)](ClO.sub.4).sub.2 is very suitable.

  3. Tritium in water vapor in the shallow unsaturated zone at the Amargosa Desert Research Site

    USGS Publications Warehouse

    Healy, Richard W.; Striegl, Robert G.; Michel, Robert L.; Prudic, David E.; Andraski, Brian J.; Morganwalp, David W.; Buxton, Herbert T.

    1999-01-01

    Samples of water vapor in soil gas were obtained at the U.S. Geological Survey's Amargosa Desert Research Site in 1997 and 1998 from a depth of 1.5 m (meters) within a 300 m by 300 m grid that lies immediately to the south and west of a low-level radioactive-waste disposal site. The gas samples were analyzed for tritium. Fifty-eight samples were collected in May 1997; 61 samples were collected in June 1998. Measured tritium concentrations ranged from 16 ± 9 TU (tritium units) to 36,900 ± 300 TU in 1997, and from 6 ± 6 TU to 37,360 ± 450 TU in 1998. Concentrations decreased from northeast to southwest across the grid. In general, there was very little difference in tritium concentrations between the two sampling periods.

  4. Capture of Tritium Released from Cladding in the Zirconium Recycle Process

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

    Spencer, Barry B.; Walker, T. B.; Bruffey, Stephanie H.

    2016-08-31

    This report is issued as the first revision to FCRD-MRWFD-2016-000297. Zirconium may be recovered from the Zircaloy® cladding of used nuclear fuel (UNF) for recycle or to reduce the quantities of high-level waste destined for a geologic repository. Recovery of zirconium using a chlorination process is currently under development at the Oak Ridge National Laboratory. The approach is to treat the cladding with chlorine gas to convert the zirconium in the alloy (~98 wt % of the alloy mass) to zirconium tetrachloride. A significant fraction of the tritium (0–96%) produced in nuclear fuel during irradiation may be found in zirconium-basedmore » cladding and could be released from the cladding when the solid matrix is destroyed by the chlorination reaction. To prevent uncontrolled release of radioactive tritium to other parts of the plant or to the environment, a method to recover the tritium may be required. The focus of this effort was to (1) identify potential methods for the recovery of tritium from the off-gas of the zirconium recycle process, (2) perform scoping tests on selected recovery methods using non-radioactive gas simulants, and (3) select a process design appropriate for testing on radioactive gas streams generated by the engineering-scale zirconium recycle demonstrations on radioactive used cladding.« less

  5. Partitioning of tritium between surface and bulk of 316 stainless steel at room temperature

    DOE PAGES

    Sharpe, M. D.; Fagan, C.; Shmayda, W. T.; ...

    2018-03-28

    The distribution of tritium between the near surface and the bulk of 316 stainless steel has been measured using two independent techniques: pulsed-plasma exposures and a zinc-chloride wash. Between 17% and 20% of the total inventory absorbed into a stainless-steel sample during a 24-h exposure to DT gas at room temperature resides in the water layers present on the metal surface. Redistribution of tritium between the surface and the bulk of stainless steel, if it occurs, is very slow. Finally, tritium does not appear to enter into the bulk at a rate defined solely by lattice diffusivity.

  6. Partitioning of tritium between surface and bulk of 316 stainless steel at room temperature

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

    Sharpe, M. D.; Fagan, C.; Shmayda, W. T.

    The distribution of tritium between the near surface and the bulk of 316 stainless steel has been measured using two independent techniques: pulsed-plasma exposures and a zinc-chloride wash. Between 17% and 20% of the total inventory absorbed into a stainless-steel sample during a 24-h exposure to DT gas at room temperature resides in the water layers present on the metal surface. Redistribution of tritium between the surface and the bulk of stainless steel, if it occurs, is very slow. Finally, tritium does not appear to enter into the bulk at a rate defined solely by lattice diffusivity.

  7. The synthesis of a tritium, carbon-14, and stable isotope-labeled cathepsin C inhibitors.

    PubMed

    Allen, Paul; Bragg, Ryan A; Caffrey, Moya; Ericsson, Cecilia; Hickey, Michael J; Kingston, Lee P; Elmore, Charles S

    2017-02-01

    As part of a medicinal chemistry program aimed at developing a highly potent and selective cathepsin C inhibitor, tritium, carbon-14, and stable isotope-labeled materials were required. The synthesis of tritium-labeled methanesulfonate 5 was achieved via catalytic tritiolysis of a chloro precursor, albeit at a low radiochemical purity of 67%. Tritium-labeled AZD5248 was prepared via a 3-stage synthesis, utilizing amide-directed hydrogen isotope exchange. Carbon-14 and stable isotope-labeled AZD5248 were successfully prepared through modifications of the medicinal chemistry synthetic route, enabling the use of available labeled intermediates. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Theoretical investigation of isotope exchange reaction in tritium-contaminated mineral oil in vacuum pump.

    PubMed

    Dong, Liang; Xie, Yun; Du, Liang; Li, Weiyi; Tan, Zhaoyi

    2015-04-28

    The mechanism of the isotope exchange reaction between molecular tritium and several typical organic molecules in vacuum pump mineral oil has been investigated by density functional theory (DFT), and the reaction rates are determined by conventional transition state theory (TST). The tritium-hydrogen isotope exchange reaction can proceed with two different mechanisms, the direct T-H exchange mechanism and the hyrogenation-dehydrogenation exchange mechanism. In the direct exchange mechanism, the titrated product is obtained through one-step via a four-membered ring hydrogen migration transition state. In the hyrogenation-dehydrogenation exchange mechanism, the T-H exchange could be accomplished by the hydrogenation of the unsaturated bond with tritium followed by the dehydrogenation of HT. Isotope exchange between hydrogen and tritium is selective, and oil containing molecules with OH and COOH groups can more easily exchange hydrogen for tritium. For aldehydes and ketones, the ability of T-H isotope exchange can be determined by the hydrogenation of T2 or the dehydrogenation of HT. The molecules containing one type of hydrogen provide a single product, while the molecules containing different types of hydrogens provide competitive products. The rate constants are presented to quantitatively estimate the selectivity of the products. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. In-pile tritium-permeation measurements on T91 tubes with double walls or a Fe-Al/Al 2O 3 coating

    NASA Astrophysics Data System (ADS)

    Conrad, R.; Bakker, K.; Chabrol, C.; Fütterer, M. A.; van der Laan, J. G.; Rigal, E.; Stijkel, M. P.

    2000-12-01

    Two new irradiation projects are being performed at the HFR Petten, named EXOTIC-8.9 and EXOTIC-8.10. Issues such as tritium release from candidate ceramic breeder pebbles for the HCPB blanket and tritium permeation through cooling tubes of the WCLL blanket are investigated simultaneously. In EXOTIC-8.9, the tritium release behaviour of a Li 2TiO 3 pebble bed is measured along with the tritium-permeation rate through a double-wall tube (DWT) of T91 with a Cu interlayer. In EXOTIC-8.10, the tritium release behaviour of a Li 4SiO 4 pebble bed is measured along with the tritium permeation rate through a T91 tube with a Fe-Al/Al 2O 3 coating as tritium permeation barrier (TPB). Tritium permeation phenomena are studied by variations of temperatures and purge gas conditions. This paper reports on the results of the first 100 irradiation days.

  10. Biological effects of tritium on fish cells in the concentration range of international drinking water standards.

    PubMed

    Stuart, Marilyne; Festarini, Amy; Schleicher, Krista; Tan, Elizabeth; Kim, Sang Bog; Wen, Kendall; Gawlik, Jilian; Ulsh, Brant

    2016-10-01

    To evaluate whether the current Canadian tritium drinking water limit is protective of aquatic biota, an in vitro study was designed to assess the biological effects of low concentrations of tritium, similar to what would typically be found near a Canadian nuclear power station, and higher concentrations spanning the range of international tritium drinking water standards. Channel catfish peripheral blood B-lymphoblast and fathead minnow testis cells were exposed to 10-100,000 Bq l(-1) of tritium, after which eight molecular and cellular endpoints were assessed. Increased numbers of DNA strand breaks were observed and ATP levels were increased. There were no increases in γH2AX-mediated DNA repair. No differences in cell growth were noted. Exposure to the lowest concentrations of tritium were associated with a modest increase in the viability of fathead minnow testicular cells. Using the micronucleus assay, an adaptive response was observed in catfish B-lymphoblasts. Using molecular endpoints, biological responses to tritium in the range of Canadian and international drinking water standards were observed. At the cellular level, no detrimental effects were noted on growth or cycling, and protective effects were observed as an increase in cell viability and an induced resistance to a large challenge dose.

  11. Semi-active control of tracked vehicle suspension incorporating magnetorheological dampers

    NASA Astrophysics Data System (ADS)

    Ata, W. G.; Salem, A. M.

    2017-05-01

    In past years, the application of magnetorheological (MR) and electrorheological dampers in vehicle suspension has been widely studied, mainly for the purpose of vibration control. This paper presents theoretical study to identify an appropriate semi-active control method for MR-tracked vehicle suspension. Three representative control algorithms are simulated including the skyhook, hybrid and fuzzy-hybrid controllers. A seven degrees-of-freedom tracked vehicle suspension model incorporating MR dampers has been adopted for comparison between the performance of the three controllers. The model differential equations are derived based on Newton's second law of motion and the proposed control methods are developed. The performance of each control method under bump and sinusoidal road profiles for different vehicle speeds is simulated and compared with the performance of the conventional suspension system in time and frequency domains. The results show that the performance of tracked vehicle suspension with MR dampers is substantially improved. Moreover, the fuzzy-hybrid controller offers an excellent integrated performance in reducing the body accelerations as well as wheel bounce responses compared with the classical skyhook and hybrid controllers.

  12. Preparatory steps for a robust dynamic model for organically bound tritium dynamics in agricultural crops

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

    Melintescu, A.; Galeriu, D.; Diabate, S.

    2015-03-15

    The processes involved in tritium transfer in crops are complex and regulated by many feedback mechanisms. A full mechanistic model is difficult to develop due to the complexity of the processes involved in tritium transfer and environmental conditions. First, a review of existing models (ORYZA2000, CROPTRIT and WOFOST) presenting their features and limits, is made. Secondly, the preparatory steps for a robust model are discussed, considering the role of dry matter and photosynthesis contribution to the OBT (Organically Bound Tritium) dynamics in crops.

  13. Tritium and decay helium effects on the fracture toughness properties of types 316L, 304L and 21Cr-6Ni-9Mn stainless steels

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

    Morgan, M.J.; Tosten, M.H

    1994-10-01

    J-integral fracture mechanics techniques and electron microscopy observations were used to investigate the effects of tritium and its radioactive decay product, {sup 3}He, on Types 316L, 304L and 21Cr-6Ni-9Mn stainless steels. Tritium-exposed-and-aged steels had lower fracture-toughness values and shallower sloped crack-growth-resistance curves than unexposed steels. Both fracture-toughness parameters decreased with increasing concentrations of {sup 3}He. The fracture-toughness reductions were accompanied by a change in fracture mode from microvoid-nucleation-and-growth processes in control samples to grain-and-twin-boundary fracture in tritium-charged-and-aged samples. Type 316L stainless steel had the highest fracture-toughness values and Type 21Cr-6Ni-9Mn had the lowest. Samples containing {sup 3}He but degassed ofmore » tritium had fracture toughness properties that were similar to uncharged samples. The results indicate that helium bubbles enhance the embrittlement effects of hydrogen by affecting the deformation properties and by increasing localized hydrogen concentrations through trapping effects.« less

  14. Enhancement of tritium concentrations on uptake by marine biota: experience from UK coastal waters.

    PubMed

    Hunt, G J; Bailey, T A; Jenkinson, S B; Leonard, K S

    2010-03-01

    Concentrations of tritium in sea water and marine biota as reported over the last approximately 10 years from monitoring programmes carried out by this laboratory under contract to the UK Food Standards Agency are reviewed from three areas: near Cardiff; Sellafield; and Hartlepool. Near Cardiff, enhancement of concentration factors (CFs) above an a priori value of approximately 1 have already been studied, and attributed to compounds containing organically bound tritium in local radioactive waste discharges. Further data for Cardiff up to 2006 are reported in this note. Up to 2001, CFs increased to values of more than approximately 7000 in flounders and approximately 4000 in mussels, but have subsequently reduced; this variability could be due to changes in the organic constitution of compounds discharged. Near Sellafield and Hartlepool, enhancements to the tritium concentration factor are observed but they are relatively small compared with those near Cardiff. Near Sellafield, plaice and mussels appear to have a CF for tritium of approximately 10; in some cases concentrations of tritium in winkles are below detection limits and positively measured values indicate a CF of approximately 3. The variation could be due to mechanisms of uptake by the different organisms. Near Hartlepool there were only a few cases where tritium was positively measured. These data give a value of approximately 5 for the CF in plaice (on the basis of two samples); approximately 15 in winkles (eight samples); and > 45 in mussels (two samples). Any differences between the behaviours at Sellafield and Hartlepool would need to be confirmed by improved measurements. Possible causes are the organic composition of the effluent and differences in environmental behaviour and uptake by organisms near the two sites. These potential causes need further investigation. It is emphasised that results from tritium analyses are heavily method dependent; thus comparison with results from other programmes

  15. Preliminary risks associated with postulated tritium release from production reactor operation

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

    O'Kula, K.R.; Horton, W.H.

    1988-01-01

    The Probabilistic Risk Assessment (PRA) of Savannah River Plant (SRP) reactor operation is assessing the off-site risk due to tritium releases during postulated full or partial loss of heavy water moderator accidents. Other sources of tritium in the reactor are less likely to contribute to off-site risk in non-fuel melting accident scenarios. Preliminary determination of the frequency of average partial moderator loss (including incidents with leaks as small as .5 kg) yields an estimate of /approximately/1 per reactor year. The full moderator loss frequency is conservatively chosen as 5 /times/ 10/sup /minus/3/ per reactor year. Conditional consequences, determined with amore » version of the MACCS code modified to handle tritium, are found to be insignificant. The 95th percentile individual cancer risk is 4 /times/ 10/sup /minus/8/ per reactor year within 16 km of the release point. The full moderator loss accident contributes about 75% of the evaluated risks. 13 refs., 4 figs., 5 tabs.« less

  16. A laboratory information management system for the analysis of tritium (3H) in environmental waters.

    PubMed

    Belachew, Dagnachew Legesse; Terzer-Wassmuth, Stefan; Wassenaar, Leonard I; Klaus, Philipp M; Copia, Lorenzo; Araguás, Luis J Araguás; Aggarwal, Pradeep

    2018-07-01

    Accurate and precise measurements of low levels of tritium ( 3 H) in environmental waters are difficult to attain due to complex steps of sample preparation, electrolytic enrichment, liquid scintillation decay counting, and extensive data processing. We present a Microsoft Access™ relational database application, TRIMS (Tritium Information Management System) to assist with sample and data processing of tritium analysis by managing the processes from sample registration and analysis to reporting and archiving. A complete uncertainty propagation algorithm ensures tritium results are reported with robust uncertainty metrics. TRIMS will help to increase laboratory productivity and improve the accuracy and precision of 3 H assays. The software supports several enrichment protocols and LSC counter types. TRIMS is available for download at no cost from the IAEA at www.iaea.org/water. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. The global geochemistry of bomb-produced tritium - General circulation model compared to available observations and traditional interpretations

    NASA Technical Reports Server (NTRS)

    Koster, Randal D.; Broecker, Wallace S.; Jouzel, Jean; Suozzo, Robert J.; Russell, Gary L.; Rind, David

    1989-01-01

    Observational evidence suggests that of the tritium produced during nuclear bomb tests that has already reached the ocean, more than twice as much arrived through vapor impact as through precipitation. In the present study, the Goddard Institute for Space Studies 8 x 10 deg atmospheric general circulation model is used to simulate tritium transport from the upper atmosphere to the ocean. The simulation indicates that tritium delivery to the ocean via vapor impact is about equal to that via precipitation. The model result is relatively insensitive to several imposed changes in tritium source location, in model parameterizations, and in model resolution. Possible reasons for the discrepancy are explored.

  18. Assessment of geraniol-incorporated polymers to control Aedes albopictus (Diptera: culicidae)

    PubMed Central

    Chuaycharoensuk, T.; Manguin, S.; Duvallet, G.; Chareonviriyaphap, T.

    2012-01-01

    Effective control of mosquito borne diseases has proven extremely difficult with both vector and pathogen remaining entrenched and expanding in many disease endemic areas. When lacking an effective vaccine, vector control methods targeting both larval habitats and adult mosquito populations remain the primary strategy for reducing risk. Aedes albopictus from Thailand was used as a reference baseline for evaluation of natural insecticides incorporated in polymer disks and pellets and tested both in laboratory and field conditions. In laboratory and field tests, the highest larval mortality was obtained with disks or pellets containing IKHC (Insect Killer Highly Concentrate) from Fulltec AG Company. This product is reputed to contain geraniol as an active ingredient. With pellets, high mortality of Ae. albopictus larvae (92%) was observed in presence of 1 g of pellets per 500 ml of water at day 1st, and the mortality was 100% at day 1st for larvae in presence of 5 or 10 g of pellets. Fulltec AG Company has not accepted to give us the exact composition of their IKHC product. Therefore, we cannot recommend it, but the principle of using monoterpenes like geraniol, incorporated into polymer disks or pellets as natural larvicide needs more attention as it could be considered as a powerful alternative in mosquito vector control. PMID:22910616

  19. TRITIUM, ARGON 37, AND MANGANESE 54 RADIOACTIVITIES IN A FRAGMENT OF SPUTNIK 4

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

    DeFelice, J.; Fireman, E.L.; Tilles, D.

    1963-09-15

    Tritium, Ar/sup 37/, and Mn/sup 54/ radioactivities were measured in samples from a steel fragment of Sputnik 4. The tritium activity was low compared with the amount expected to be produced by cosmic rays. Some metallurgical evidence suggests the possibility that the lowest tritium content was in the sample that may have experienced the most heating. The amount of manganese 54 radioactivity was approximately 40% of the value obtained in Aroos by others, whereas the amount of Ar/sup 37/ was about 20% of that measured in Aroos and about 30% of that estimated from the Ar/sup 39/ measurements in Aroos,more » Norfork, Pitts, and Treysa, together with the ratio of production cross sections. (auth)« less

  20. Effects of tritium gas exposure on the dynamic mechanical properties of EPDM elastomer

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

    Clark, E. A.; Staack, G. C.

    2008-07-15

    Samples of ethylene propylene diene monomer (EPDM) elastomer were exposed to tritium gas in closed containers at 101 kPa (1 atmosphere) pressure and ambient temperature for about one week. Tritium exposure effects on the samples were characterized by dynamic mechanical analysis (DMA) and radiolysis products were characterized by measuring the total final pressure and composition in the exposure containers at the end of exposure period. There was no effect of one week tritium exposure on the glass transition temperature, Tg, of the samples tested. Impurity gases produced in the closed containers included HT and lesser amounts of H{sub 2}, DTO,more » and CT{sub 4}. The total pressure remained the same during exposure. (authors)« less

  1. EFFECTS OF TRITIUM GAS EXPOSURE ON THE DYNAMIC MECHANICAL PROPERTIES OF EPDM ELASTOMER

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

    Clark, E; Gregory Staack, G

    2007-08-13

    Samples of ethylene propylene diene monomer (EPDM) elastomer were exposed to tritium gas in closed containers initially at 101 kPa (1 atmosphere) pressure and ambient temperature for about one week. Tritium exposure effects on the samples were characterized by dynamic mechanical analysis (DMA) and radiolysis products were characterized by measuring the total final pressure and composition in the exposure containers at the end of exposure period. There was no effect of one week tritium exposure on the glass transition temperature, Tg, of the samples tested. Impurity gases produced in the closed containers included HT and lesser amounts of H{sub 2},more » DTO, and CT{sub 4}. The total pressure remained the same during exposure.« less

  2. [Study on Tritium Content in Soil at Sites of Nuclear Explosions on the Territory of Semipalatinsk Test Site].

    PubMed

    Timonova, L V; Lyakhova, O N; Lukashenko, S N; Aidarkhanov, A O

    2015-01-01

    As a result of investigations carried out on the territory of Semipalatinsk Test Site, tritium was found in different environmental objects--surface and ground waters, vegetation, air environment, and snow cover. The analysis of the data obtained has shown that contamination of environmental objects at the Semipalatinsk Test Site with tritium is associated with the places where underground nuclear tests were performed. Since tritium can originate from an activation reaction and be trapped by pock particles during a test, it was decided to examine the soil in the sites where surface and excavation tests took place. It was found that the concentration of tritium in soil correlates with the concentration of europium. Probably, the concentration of tritium in the soil depends on the character and yield of the tests performed. Findings of the study have revealed that tritium can be found in soil in significant amounts not only in sites where underground nuclear tests took place but also in sites where surface and excavation nuclear tests were carried out.

  3. Tritium and plutonium in waters from the Bering and Chukchi Seas

    USGS Publications Warehouse

    Landa, E.R.; Beals, D.M.; Halverson, J.E.; Michel, R.L.; Cefus, G.R.

    1999-01-01

    During the summer of 1993, seawater in the Bering and Chukchi Seas was sampled on a joint Russian-American cruise [BERPAC] of the RV Okean to determine concentrations of tritium, 239Pu and 240Pu. Concentrations of tritium were determined by electrolytic enrichment and liquid scintilation counting. Tritium levels ranged up to 420 mBq L-1 showed no evidence of inputs other than those attribute atmospheric nuclear weapons testing. Plutonium was recovered from water samples by ferric hydroxide precipitation, and concentrations were determined by thermal ionization mass spectrometry. 239+240Pu concentrations ranged from <1 to 5.5 [mu]Bq L-1. These concentrations are lower than those measured in water samples from other parts of the ocean during the mid-1960's to the late 1980's. The 240Pu:239Pu ratios, although associated with large uncertainties, suggest that most of the plutonium is derived from world-wide fallout. As points of comparison, the highest concentrations of tritium and plutonium observed here were about five orders of magnitude lower than the maximum permissible concentrations allowed in water released to the off-site environs from licensed nuclear facilities in the United States. This study and others sponsored by the International Atomic Energy Agency and the Office of Naval Research's Arctic Nuclear Waste Assessment Program are providing data for the assessment of potential radiological impacts in the Arctic regions associated with nuclear waste disposal by the former Soviet Union.

  4. Modeling of tritium transport in a fusion reactor pin-type solid breeder blanket using the diffuse code

    NASA Astrophysics Data System (ADS)

    Martin, Rodger; Ghoniem, Nasr M.

    1986-11-01

    A pin-type fusion reactor blanket is designed using γ-LiAlO 2 solid tritium breeder. Tritium transport and diffusive inventory are modeled using the DIFFUSE code. Two approaches are used to obtain characteristic LiAlO 2 grain temperatures. DIFFUSE provides intragranular diffusive inventories which scale up to blanket size. These results compare well with a numerical analysis, giving a steady-state blanket tritium inventory of 13 g. Start-up transient inventories are modeled using DIFFUSE for both full and restricted coolant flow. Full flow gives rapid inventory buildup while restricted flow prevents this buildup. Inventories after shutdown are modeled: reduced cooling is found to have little effect on removing tritium, but preheating rapidly purges inventory. DIFFUSE provides parametric modeling of solid breeder density, radiation, and surface effects. 100% dense pins are found to give massive inventory and marginal tritium release. Only large trapping energies and concentrations significantly increase inventory. Diatomic surface recombination is only significant at high temperatures.

  5. Spatial variations of tritium concentrations in groundwater collected in the southern coastal region of Fukushima, Japan, after the nuclear accident.

    PubMed

    Kashiwaya, Koki; Muto, Yuta; Kubo, Taiki; Ikawa, Reo; Nakaya, Shinji; Koike, Katsuaki; Marui, Atsunao

    2017-10-03

    Spatial variations in tritium concentrations in groundwater were identified in the southern part of the coastal region in Fukushima Prefecture, Japan. Higher tritium concentrations were measured at wells near the Fukushima Daiichi Nuclear Power Station (F1NPS). Mean tritium concentrations in precipitation in the 5 weeks after the F1NPS accident were estimated to be 433 and 139 TU at a distance of 25 and 50 km, respectively, from the F1NPS. The elevations of tritium concentrations in groundwater were calculated using a simple mixing model of the precipitation and groundwater. By assuming that these precipitation was mixed into groundwater with a background tritium concentration in a hypothetical well, concentrations of 13 and 7 TU at distances of 25 and 50 km from the F1NPS, respectively, were obtained. The calculated concentrations are consistent with those measured at the studied wells. Therefore, the spatial variation in tritium concentrations in groundwater was probably caused by precipitation with high tritium concentrations as a result of the F1NPS accident. However, the highest estimated tritium concentrations in precipitation for the study site were much lower than the WHO limits for drinking water, and the concentrations decreased to almost background level at the wells by mixing with groundwater.

  6. Assessment of the importance of neutron multiplication for tritium production

    NASA Astrophysics Data System (ADS)

    Chiovaro, P.; Di Maio, P. A.

    2017-01-01

    One of the major requirements for a fusion power plant in the future is tritium self-sufficiency. For this reason the scientific community has dedicated a lot of effort to research activity on reactor tritium breeding blankets. In the framework of the international project DEMO, many concepts of breeding blanket have been taken into account and some of them will be tested in the experimental reactor ITER by means of appropriate test blanket modules (TBMs). All the breeding blanket concepts rely on the adoption of binary systems composed of a material acting as neutronic multiplier and another as a breeder. This paper addresses a neutronic feature of these kinds of systems. In particular, attention has been focused on the assessment of the importance of neutrons coming from multiplication reactions for the production of tritium. A theoretical framework has been set up and a procedure to evaluate the performance of the multiplier-breeder systems, under the aforementioned point of view, has been developed. Moreover, the model set up has been applied to helium cooled lithium lead and helium cooled pebble bad TBMs under irradiation in ITER and the results have been critically discussed.

  7. Region-specific tritium enrichment, and not differential beta-absorption, is the major cause of 'quenching' in film autoradiography.

    PubMed

    McEachron, D L; Nissanov, J; Tretiak, O J

    1997-06-01

    Tritium quenching refers to the situation in which estimates of tritium content generated by film autoradiography depend on the chemical composition of the tissue as well as on the concentration of the radioisotope. When analysing thin brain sections, for example, regions rich in lipid content generate reduced optical densities on x-ray film compared with lipid-poor regions even when the total tissue concentration of tritium in those regions is identical. We hypothesize that the dried thickness of regions within sections depends upon the relative concentrations and types of lipid within the regions. Areas low in white matter dry thinner than areas high in white matter, leading to a relative enrichment of tritium in the thinner regions. To test this model, a series of brain pastes were made with different concentrations of grey and white matter and impregnated with equal amounts of tritium. The thickness of dried sections was compared with percentage of white matter and apparent radioactive content as determined by autoradiogram analysis. The results demonstrated that thickness increased, and apparent radioactivity decreased, with higher percentages of white matter. In the second experiment, thickness measurements from dried sections were successfully used to correct the apparent radioisotope content of autoradiograms created from tritium containing white- and grey-matter tissue slices. We conclude that within-section thickness variation is the major physical cause for 'tritium quenching'.

  8. Tritium Concentrations in Environmental Samples and Transpiration Rates from the Vicinity of Mary's Branch Creek and Background Areas, Barnwell, South Carolina, 2007-2009

    USGS Publications Warehouse

    Vroblesky, Don A.; Canova, Judy L.; Bradley, Paul M.; Landmeyer, James E.

    2009-01-01

    Tritium in groundwater from a low-level radioactive waste disposal facility near Barnwell, South Carolina, is discharging to Mary's Branch Creek. The U.S. Geological Survey conducted an investigation from 2007 to 2009 to examine the tritium concentration in trees and air samples near the creek and in background areas, in groundwater near the creek, and in surface water from the creek. Tritium was found in trees near the creek, but not in trees from background areas or from sites unlikely to be in direct root contact with tritium-contaminated groundwater. Tritium was found in groundwater near the creek and in the surface water of the creek. Analysis of tree material has the potential to be a useful tool in locating shallow tritium-contaminated groundwater. A tritium concentration of 1.4 million picocuries per liter was measured in shallow groundwater collected near a tulip poplar located in an area of tritium-contaminated groundwater discharge. Evapotranspiration rates from the tree and tritium concentrations in water extracted from tree cores indicate that during the summer, this tulip poplar may remove more than 17.1 million picocuries of tritium per day from the groundwater that otherwise would discharge to Mary's Branch Creek. Analysis of air samples near the tree showed no evidence that the transpirative release of tritium to the air created a vapor hazard in the forest.

  9. EXTRACTION OF FRACTURE-MECHANICS AND TRANSMISSION-ELECTRON-MICROSCOPY SAMPLES FROM TRITIUM-EXPOSED RESERVOIRS USING ELECTRIC-DISCHARGE MACHINING

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

    Morgan, M; Ken Imrich, K; Michael Tosten, M

    2006-08-31

    The Enhanced Surveillance Campaign is funding a program to investigate tritium aging effects on the structural properties of tritium reservoir steels. The program is designed to investigate how the structural properties of reservoir steels change during tritium service and to examine the role of microstructure and reservoir manufacturing on tritium compatibility. New surveillance tests are also being developed that can better gauge the long-term effects of tritium and its radioactive decay product, helium-3, on the properties of reservoir steels. In order to conduct these investigations, three types of samples are needed from returned reservoirs: tensile, fracture mechanics, and transmission-electron microscopymore » (TEM). An earlier report demonstrated how the electric-discharge machining (EDM) technique can be used for cutting tensile samples from serial sections of a 3T reservoir and how yield strength, ultimate strength and elongation could be measured from those samples. In this report, EDM was used successfully to section sub-sized fracture-mechanics samples from the inner and outer walls of a 3T reservoir and TEM samples from serial sections of a 1M reservoir. This report fulfills the requirements for the FY06 Level 3 milestone, TSR 15.1 ''Cut Fracture-Mechanics Samples from Tritium-Exposed Reservoir'' and TSR 15.2 ''Cut Transmission-electron-microscopy foils from Tritium-Exposed Reservoir'' for the Enhance Surveillance Campaign (ESC). This was in support of ESC L2-1870 Milestone-''Provide aging and lifetime assessments of selected components and materials for multiple enduring stockpile systems''.« less

  10. 18 years of continuous observation of tritium and atmospheric precipitations in Ramnicu Valcea (Romania): A time series analysis.

    PubMed

    Duliu, Octavian G; Varlam, Carmen; Shnawaw, Muataz Dheyaa

    2018-05-16

    To get more information on the origin of tritium and to evidence any possible presence of anthropogenic sources, between January 1999 and December 2016, the precipitation level and tritium concentration were monthly recorded and investigated by the Cryogenic Institute of Ramnicu Valcea, Romania. Compared with similar data covering a radius of about 1200 km westward, the measurements gave similar results concerning the time evolution of tritium content and precipitation level for the entire time interval excepting the period between 2009 and 2011 when the tritium concentrations showed a slight increase, most probable due to the activity of neighboring experimental pilot plant for tritium and deuterium separation. Regardless this fact, all data pointed towards a steady tendency of tritium concentrations to decrease with an annual rate of about 1.4 ± 0.05%. The experimental data on precipitation levels and tritium concentrations form two complete time series whose time series analysis showed, at p < 0.01, the presence of a single one-year periodicity whose coincident maximums which correspond to late spring - early summer months suggest the existence of the Spring Leak mechanism with a possible contribution of the soil moisture remobilization during the warm period. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Tritium and radiocarbon in the western North Pacific waters: post-Fukushima situation.

    PubMed

    Kaizer, Jakub; Aoyama, Michio; Kumamoto, Yuichiro; Molnár, Mihály; Palcsu, László; Povinec, Pavel P

    2018-04-01

    Impact of the Fukushima Dai-ichi Nuclear Power Plant (FNPP1) accident on tritium ( 3 H) and radiocarbon ( 14 C) levels in the water column of the western North Pacific Ocean in winter 2012 is evaluated and compared with radiocesium ( 134,137 Cs) data collected for the same region. Tritium concentrations in surface seawater, varying between 0.4 and 2.0 TU (47.2-236 Bq m -3 ), follow the Fukushima radiocesium trend, however, some differences in the vertical profiles were observed, namely in depths of 50-400 m. No correlation was visible in the case of 14 C, whose surface Δ 14 C levels raised from negative values (about -40‰) in the northern part of transect, to positive values (∼68‰) near the equator. Homogenously mixed 14 C levels in the subsurface layers were observed at all stations. Sixteen surface (from 30 in total) and 6 water profile (from 7) stations were affected by the Fukushima tritium. Surface and vertical profile data together with the calculated water column inventories indicate that the total amount of the FNPP1-derived tritium deposited to the western North Pacific Ocean was 0.7 ± 0.3 PBq. No clear impact of the Fukushima accident on 14 C levels in the western North Pacific was observed. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Simulation of background from low-level tritium and radon emanation in the KATRIN spectrometers

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

    Leiber, B.; Collaboration: KATRIN Collaboration

    The KArlsruhe TRItium Neutrino (KATRIN) experiment is a large-scale experiment for the model independent determination of the mass of electron anti-neutrinos with a sensitivity of 200 meV/c{sup 2}. It investigates the kinematics of electrons from tritium beta decay close to the endpoint of the energy spectrum at 18.6 keV. To achieve a good signal to background ratio at the endpoint, a low background rate below 10{sup −2} counts per second is required. The KATRIN setup thus consists of a high luminosity windowless gaseous tritium source (WGTS), a magnetic electron transport system with differential and cryogenic pumping for tritium retention, andmore » electro-static retarding spectrometers (pre-spectrometer and main spectrometer) for energy analysis, followed by a segmented detector system for counting transmitted beta-electrons. A major source of background comes from magnetically trapped electrons in the main spectrometer (vacuum vessel: 1240 m{sup 3}, 10{sup −11} mbar) produced by nuclear decays in the magnetic flux tube of the spectrometer. Major contributions are expected from short-lived radon isotopes and tritium. Primary electrons, originating from these decays, can be trapped for hours, until having lost almost all their energy through inelastic scattering on residual gas particles. Depending on the initial energy of the primary electron, up to hundreds of low energetic secondary electrons can be produced. Leaving the spectrometer, these electrons will contribute to the background rate. This contribution describes results from simulations for the various background sources. Decays of {sup 219}Rn, emanating from the main vacuum pump, and tritium from the WGTS that reaches the spectrometers are expected to account for most of the background. As a result of the radon alpha decay, electrons are emitted through various processes, such as shake-off, internal conversion and the Auger deexcitations. The corresponding simulations were done using the

  13. Preheating temperature effect on tritium retention in VPS-W

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

    Sato, M.; Uchimura, H.; Toda, K.

    The W coating by Vacuum Plasma Spraying (VPS) technology is thought to be reasonable for most plasma facing components in future fusion reactors. In this paper the deuterium retention behavior for the Vacuum Plasma Spraying (VPS) tungsten (W) coating has been studied to demonstrate the tritium retention as a function of heating temperature. It has been found that two major deuterium desorption stages were observed at the temperature regions of 400 - 700 K (Stage 1) and 900 - 1100 K (Stage 2), considering that Stage 1 has been linked to the desorption of deuterium trapped by near surface andmore » intrinsic defects, and Stage 2 has been related to the desorption of deuterium bound to impurities as C-D bonds. By heating the sample above 673 K, the major peak of C-1s shifted from C-O bond to C-C bond, where the retention of deuterium as Stage 2 has increased. Therefore it indicates that the hydrogen isotope retention was controlled by the amount of C-C bond in VPS, most of which was contaminated during the VPS coating process. The comparison of several samples (VPS-W with shading, VPS-W without shading and Polycrystalline W (PCW)) shows that the carbon impurity has a large affinity with deuterium and makes stable trapping states compared to that with intrinsic defects and grain boundaries. However, most of them was reduced by heating at 1173 K. Therefore, heating treatment is quite important to get rid of carbon impurities and refrain higher tritium retention in VPS. (authors)« less

  14. Hydrogeology, ground-water flow, and tritium movement at low-level radioactive-waste disposal site near Sheffield, Illinois

    USGS Publications Warehouse

    Garklavs, George; Healy, R.W.

    1986-01-01

    Groundwater flow and tritium movement are described at and near a low-level radioactive waste disposal site near Sheffield, Illinois. Flow in the shallow aquifer is confined to three basins that ultimately drain into a stripmine lake. Most of the flow from the site is through a buried, pebbly sandfilled channel. Remaining flow is toward alluvium of an existing stream. Conceptual flow models for the two largest basins are used to improve definition of flow velocity and direction. Flow velocities range from about 25 to 2,500 ft/yr. Tritium was found in all three basins. The most extensive migration of tritium is coincident with buried channel. Tritium concentrations ranged from detection level to more than 300 nanocuries/L. (USGS)

  15. EFFECTS OF TRITIUM GAS EXPOSURE ON THE GLASS TRANSITION TEMPERATURE OF EPDM ELASTOMER AND ON THE CONDUCTIVITY OF POLYANILINE

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

    Clark, E; Marie Kane, M

    2008-12-12

    Four formulations of EPDM (ethylene-propylene diene monomer) elastomer were exposed to tritium gas initially at one atmosphere and ambient temperature for between three and four months in closed containers. Material properties that were characterized include density, volume, mass, appearance, flexibility, and dynamic mechanical properties. The glass transition temperature was determined by analysis of the dynamic mechanical property data per ASTM standards. EPDM samples released significant amounts of gas when exposed to tritium, and the glass transition temperature increased by about 3 C. during the exposure. Effects of ultraviolet and gamma irradiation on the surface electrical conductivity of two types ofmore » polyaniline films are also documented as complementary results to planned tritium exposures. Future work will determine the effects of tritium gas exposure on the electrical conductivity of polyaniline films, to demonstrate whether such films can be used as a sensor to detect tritium. Surface conductivity was significantly reduced by irradiation with both gamma rays and ultraviolet light. The results of the gamma and UV experiments will be correlated with the tritium exposure results.« less

  16. A Hydrogen Exchange Method Using Tritium and Sephadex: Its Application to Ribonuclease*

    PubMed Central

    Englander, S. Walter

    2012-01-01

    A new method for measuring the hydrogen exchange of macromolecules in solution is described. The method uses tritium to trace the movement of hydrogen, and utilizes Sephadex columns to effect, in about 2 minutes, a separation between tritiated macromolecule and tritiated solvent great enough to allow the measurement of bound tritium. High sensitivity and freedom from artifact is demonstrated and the possible value of the technique for investigation of other kinds of colloid-small molecule interaction is indicated. Competition experiments involving tritium, hydrogen, and deuterium indicate the absence of any equilibrium isotope effect in the ribonuclease-hydrogen isotope system, though a secondary kinetic isotope effect is apparent when ribonuclease is largely deuterated. Ribonuclease shows four clearly distinguishable kinetic classes of exchangeable hydrogens. Evidence is marshaled to suggest the independently measurable classes II, III, and IV (in order of decreasing rate of exchange) to represent “random-chain” peptides, peptides involved in α-helix, and otherwise shielded side-chain and peptide hydrogens, respectively. PMID:14075117

  17. Apparent enrichment of organically bound tritium in rivers explained by the heritage of our past.

    PubMed

    Eyrolle-Boyer, Frédérique; Boyer, Patrick; Claval, David; Charmasson, Sabine; Cossonnet, Catherine

    2014-10-01

    The global inventory of naturally produced tritium (3H) is estimated at 2.65 kg, whereas more than 600 kg have been released during atmospheric nuclear tests (NCRP, 1979; UNSCEAR, 2000) constituting the main source of artificial tritium throughout the Anthropocene. The behaviour of this radioactive isotope in the environment has been widely studied since the 1950s, both through laboratory experiments and, more recently, through field observations (e.g., Cline, 1953; Kirchmann et al., 1979; Daillant et al., 2004; McCubbin et al., 2001; Kim et al., 2012). In its "free" forms, [i.e. 3H gas or 3H hydride (HT); methyl 3H gas (CH3T); tritiated H2O or 3H-oxide (HTO); and Tissue Free Water 3H (TFWT)], tritium closely follows the water cycle. However, 3H bound with organic compounds, mainly during the basic stages of photosynthesis or through weak hydrogen links, is less exchangeable with water, which explains its persistence in the carbon cycle as re underlined recently by Baglan et al. (2013), Jean-Batiste and Fourré (2013), Kim et al. (2013a,b). In this paper, we demonstrate that terrestrial biomass pools, historically contaminated by global atmospheric fallout from nuclear testing, have constituted a significant delayed source of organically bound tritium (OBT) for aquatic systems, resulting in an apparent enrichment of OBT as compared to HTO. This finding helps to explain concentration factors (tritium concentration in biota/concentration in water) greater than 1 observed in areas that are not directly affected by industrial radioactive wastes, and thus sheds light on the controversies regarding tritium 'bioaccumulation'. Such apparent enrichment of OBT is expected to be more pronounced in the Northern Hemisphere where fallout was most significant, depending on the nature and biodegradability of terrestrial biomass at the regional scale. We further believe that OBT transfers from the continent to oceans have been sufficient to affect tritium concentrations in

  18. Improvement of the model for surface process of tritium release from lithium oxide

    NASA Astrophysics Data System (ADS)

    Yamaki, Daiju; Iwamoto, Akira; Jitsukawa, Shiro

    2000-12-01

    Among the various tritium transport processes in lithium ceramics, the importance and the detailed mechanism of surface reactions remain to be elucidated. The dynamic adsorption and desorption model for tritium desorption from lithium ceramics, especially Li 2O was constructed. From the experimental results, it was considered that both H 2 and H 2O are dissociatively adsorbed on Li 2O and generate OH - on the surface. In the first model developed in 1994, it was assumed that either the dissociative adsorption of H 2 or H 2O on Li 2O generates two OH - on the surface. However, recent calculation results show that the generation of one OH - and one H - is more stable than that of two OH -s by the dissociative adsorption of H 2. Therefore, assumption of H 2 adsorption and desorption in the first model is improved and the tritium release behavior from Li 2O surface is evaluated again by using the improved model. The tritium residence time on the Li 2O surface is calculated using the improved model, and the results are compared with the experimental results. The calculation results using the improved model agree well with the experimental results than those using the first model.

  19. Apparatus for the Calibration/Certification of Direct Reading Tritium in Air Monitors

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

    Otlet, R.L.; Mather, I.D.; Pottinger, M

    2005-07-15

    Direct reading tritium-in-air-monitors are widely used for immediate observation of discharges or working area levels where significant sources of tritium are held. These monitors require initial and periodic calibration certification at the levels likely to be encountered. We describe a purpose built gas handling apparatus which enables various activity levels of tritiated gas ({sup 3}H + N{sub 2}) to be precisely metered and circulated in a closed loop through the monitor under calibration at a wide range of activity levels.

  20. First tritium operation of ITER-prototype VUV spectroscopy on JET

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

    Coffey, I.H.; Barnsley, R.

    Results from tritium operation of the VUV survey spectrometer on the JET tokamak are presented. The instrument, located outside the biological shield and offset from a direct plasma 1-o-s for maximum radiation protection, was operational during the trace tritium campaign (TTE) at JET. No discernible increase in detector background noise levels were detected for total neutron rates of up to 1x10{sup 17}/s, demonstrating the shielding effectiveness of the configuration. Some tritium retention in the detector microchannel plate was measurable, but has not hampered subsequent operations. As a reference the unshielded detector of a close-coupled XUV instrument was operated during TTEmore » (the spectrometer itself was valved off from the JET vessel). This was exposed to neutron fluxes of {approx}10{sup 9}/cm{sup 2} s, in excess of those predicted for the corresponding instrument on ITER (10{sup 7}-10{sup 8}/cm{sup 2} s). A corresponding increase in the background level equivalent to {approx}5% of the detector dynamic range was measured. This demonstration of the shielding effectiveness of the SPRED configuration during DT operations, coupled with the tolerable noise levels measured in the SOXMOS detector, give confidence in the planned implementation of such instruments in ITER.« less

  1. The problem with simple lumped parameter models: Evidence from tritium mean transit times

    NASA Astrophysics Data System (ADS)

    Stewart, Michael; Morgenstern, Uwe; Gusyev, Maksym; Maloszewski, Piotr

    2017-04-01

    Simple lumped parameter models (LPMs) based on assuming homogeneity and stationarity in catchments and groundwater bodies are widely used to model and predict hydrological system outputs. However, most systems are not homogeneous or stationary, and errors resulting from disregard of the real heterogeneity and non-stationarity of such systems are not well understood and rarely quantified. As an example, mean transit times (MTTs) of streamflow are usually estimated from tracer data using simple LPMs. The MTT or transit time distribution of water in a stream reveals basic catchment properties such as water flow paths, storage and mixing. Importantly however, Kirchner (2016a) has shown that there can be large (several hundred percent) aggregation errors in MTTs inferred from seasonal cycles in conservative tracers such as chloride or stable isotopes when they are interpreted using simple LPMs (i.e. a range of gamma models or GMs). Here we show that MTTs estimated using tritium concentrations are similarly affected by aggregation errors due to heterogeneity and non-stationarity when interpreted using simple LPMs (e.g. GMs). The tritium aggregation error series from the strong nonlinearity between tritium concentrations and MTT, whereas for seasonal tracer cycles it is due to the nonlinearity between tracer cycle amplitudes and MTT. In effect, water from young subsystems in the catchment outweigh water from old subsystems. The main difference between the aggregation errors with the different tracers is that with tritium it applies at much greater ages than it does with seasonal tracer cycles. We stress that the aggregation errors arise when simple LPMs are applied (with simple LPMs the hydrological system is assumed to be a homogeneous whole with parameters representing averages for the system). With well-chosen compound LPMs (which are combinations of simple LPMs) on the other hand, aggregation errors are very much smaller because young and old water flows are treated

  2. Techniques for tritium recovery from carbon flakes and dust at the JET active gas handling system

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

    Gruenhagen, S.; Perevezentsev, A.; Brennan, P. D.

    2008-07-15

    Detritiation of highly tritium contaminated carbon and metal material used as first wall armour is a key issue for fusion machines like JET and ITER. Re-deposited carbon and hydrogen in the form of flakes and dust can lead to a build-up of the tritium inventory and therefore this material must be removed and processed. The high tritium concentration of the flake and dust material collected from the JET vacuum vessel makes it unsuitable for direct waste disposal without detritiation. A dedicated facility to process the tritiated carbon flake material and recover the tritium has been designed and built. In severalmore » test runs active material was successfully processed and de-tritiated in the new facility. Samples containing only carbon and hydrogen isotopes have been completely oxidized without any residue. Samples containing metallic impurities, e.g. beryllium, require longer processing times, adjusted processing parameters and yield an oxide residue. The detritiation factor was 2x10{sup 4}. In order to simulate in-vessel and ex-vessel detritiation techniques, the detritiation of a carbon flake sample by isotopic exchange in a hydrogen atmosphere was investigated. 2.8% of tritium was recovered by this means. (authors)« less

  3. Simultaneous measurement of tritium and radiocarbon by ultra-low-background proportional counting.

    PubMed

    Mace, Emily; Aalseth, Craig; Alexander, Tom; Back, Henning; Day, Anthony; Hoppe, Eric; Keillor, Martin; Moran, Jim; Overman, Cory; Panisko, Mark; Seifert, Allen

    2017-08-01

    Use of ultra-low-background capabilities at Pacific Northwest National Laboratory provide enhanced sensitivity for measurement of low-activity sources of tritium and radiocarbon using proportional counters. Tritium levels are nearly back to pre-nuclear test backgrounds (~2-8 TU in rainwater), which can complicate their dual measurement with radiocarbon due to overlap in the beta decay spectra. We present results of single-isotope proportional counter measurements used to analyze a dual-isotope methane sample synthesized from ~120mg of H 2 O and present sensitivity results. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Simultaneous measurement of tritium and radiocarbon by ultra-low-background proportional counting

    DOE PAGES

    Mace, Emily; Aalseth, Craig; Alexander, Tom; ...

    2016-12-21

    Use of ultra-low-background capabilities at Pacific Northwest National Laboratory provide enhanced sensitivity for measurement of low-activity sources of tritium and radiocarbon using proportional counters. Tritium levels are nearly back to pre-nuclear test backgrounds (~2-8 TU in rainwater), which can complicate their dual measurement with radiocarbon due to overlap in the beta decay spectra. In this paper, we present results of single-isotope proportional counter measurements used to analyze a dual-isotope methane sample synthesized from ~120 mg of H 2O and present sensitivity results.

  5. Transport of tritium contamination to the atmosphere in an arid environment

    USGS Publications Warehouse

    Garcia, C. Amanda; Andraski, Brian J.; Johnson, Michael J.; Stonestrom, David A.; Michel, Robert L.; Cooper, C.A.; Wheatcraft, S.W.

    2009-01-01

    Soil–plant–atmosphere interactions strongly influence water movement in desert unsaturated zones, but little is known about how such interactions affect atmospheric release of subsurface water-borne contaminants. This 2-yr study, performed at the U.S. Geological Survey's Amargosa Desert Research Site in southern Nevada, quantified the magnitude and spatiotemporal variability of tritium (3H) transport from the shallow unsaturated zone to the atmosphere adjacent to a low-level radioactive waste (LLRW) facility. Tritium fluxes were calculated as the product of 3H concentrations in water vapor and respective evaporation and transpiration water-vapor fluxes. Quarterly measured 3H concentrations in soil water vapor and in leaf water of the dominant creosote-bush [Larrea tridentata (DC.) Coville] were spatially extrapolated and temporally interpolated to develop daily maps of contamination across the 0.76-km2 study area. Maximum plant and root-zone soil concentrations (4200 and 8700 Bq L−1, respectively) were measured 25 m from the LLRW facility boundary. Continuous evaporation was estimated using a Priestley–Taylor model and transpiration was computed as the difference between measured eddy-covariance evapotranspiration and estimated evaporation. The mean evaporation/transpiration ratio was 3:1. Tritium released from the study area ranged from 0.12 to 12 μg d−1 and totaled 1.5 mg (8.2 × 1010 Bq) over 2 yr. Tritium flux variability was driven spatially by proximity to 3H source areas and temporally by changes in 3H concentrations and in the partitioning between evaporation and transpiration. Evapotranspiration removed and limited penetration of precipitation beneath native vegetation and fostered upward movement and release of 3H from below the root zone.

  6. Evaluation of the response of tritium-in-air instrumentation to HT in dry and humid conditions and to HTO vapor

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

    Phillips, H.; Dean, J.; Privas, E.

    2015-03-15

    Nuclear plant operators (power generation, decommissioning and reprocessing operations) are required to monitor releases of tritium species for regulatory compliance and radiation protection purposes. Tritium monitoring is performed using tritium-in-air gas monitoring instrumentation based either on flow-through ion chambers or proportional counting systems. Tritium-in-air monitors are typically calibrated in dry conditions but in service may operate at elevated levels of relative humidity. The NPL (National Physical Laboratory) radioactive gas-in-air calibration system has been used to study the effect of humidity on the response to tritium of two tritium-in-air ion chamber based monitors and one proportional counting system which uses amore » P10/air gas mixture. The response of these instruments to HTO vapour has also been evaluated. In each case, instrument responses were obtained for HT in dry conditions (relative humidity (RH) about 2%), HT in 45% RH, and finally HTO at 45% RH. Instrumentation response to HT in humid conditions has been found to slightly exceed that in dry conditions. (authors)« less

  7. Duplex recombinase polymerase amplification assays incorporating competitive internal controls for bacterial meningitis detection.

    PubMed

    Higgins, Owen; Clancy, Eoin; Forrest, Matthew S; Piepenburg, Olaf; Cormican, Martin; Boo, Teck Wee; O'Sullivan, Nicola; McGuinness, Claire; Cafferty, Deirdre; Cunney, Robert; Smith, Terry J

    2018-04-01

    Recombinase polymerase amplification (RPA) is an isothermal nucleic acid amplification technology that provides rapid and robust infectious disease pathogen detection, ideal for point-of-care (POC) diagnostics in disease-prevalent low-resource countries. We have developed and evaluated three duplex RPA assays incorporating competitive internal controls for the detection of leading bacterial meningitis pathogens. Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae singleplex RPA assays were initially developed and evaluated, demonstrating 100% specificity with limits of detection of 4.1, 8.5 and 3.9 genome copies per reaction, respectively. Each assay was further developed into internally controlled duplex RPA assays via the incorporation of internal amplification control templates. Clinical performance of each internally controlled duplex RPA assay was evaluated by testing 64 archived PCR-positive clinical samples. Compared to real-time PCR, all duplex RPA assays demonstrated 100% diagnostic specificity, with diagnostic sensitivities of 100%, 86.3% and 100% for the S. pneumoniae, N. meningitidis and H. influenzae assays, respectively. This study details the first report of internally controlled duplex RPA assays for the detection of bacterial meningitis pathogens: S. pneumoniae, N. meningitidis and H. influenzae. We have successfully demonstrated the clinical diagnostic utility of each duplex RPA assay, introducing effective diagnostic technology for POC bacterial meningitis identification in disease-prevalent developing countries. Copyright © 2018 Elsevier Inc. All rights reserved.

  8. Low-level radioactive-waste burial at the Palos Forest Preserve, Illinois; geology and hydrology of the glacial drift, as related to the migration of tritium

    USGS Publications Warehouse

    Olimpio, Julio C.

    1984-01-01

    A low-level radioactive-waste burial site is located in Palos Forest Preserve, about 22 kilometers southwest of Chicago, Illinois. Between 1943 and 1949 the site, named Plot M, was filled with radioactive waste from the first Argonne National Laboratory and from the University of Chicago Metallurgical Laboratory. Since 1973, tritium concentration levels up to 14 nanocuries per liter have been measured in water samples collected from a well 360 meters from the burial site. The U.S. Geological Survey is studying the geologic, hydrologic, and geochemical properties of the glacial drift and underlying bedrock at the Plot M site to determine the factors that control the movement of radionuclides. Test wells were drilled into the drift to collect water and core samples for laboratory analysis, to gather geologic and hydrologic data, and to conduct geophysical surveys. Plot M is located in drift that ranges in thickness from 25 to 45 meters. The drift is a stratified sequence of clay- and silt-rich sediments that contain thin, interstratified sand layers. The silt content of the drift increases with depth. The permeability of the drift, as indicated by field and laboratory hydraulic conductivity tests, ranges from 1.0 x 10 -6 to 1.0 ? 10 -8 centimeters per second. A tritium plume, the contaminated zone in the drift in which tritium concentration levels exceed 10 nanocuries per liter of water, extends horizontally northward from Plot M at least 50 meters and vertically downward to bedrock. The center of the plume, where tritium concentration levels are as high as 50,000 nanocuries per liter, is approximately 15 meters beneath the burial site. The size, shape, and 'bull's-eye' concentration pattern indicate that the plume is a single slug and that the site no longer releases tritium into the drift. The leading edge, or front, of the plume (the 10 nanocuries per liter boundary) left the burial site in either the late 1940's or the early 1950's and intersected the underlying

  9. An analysis of workers' tritium concentration in urine samples as a function of time after intake at Korean pressurised heavy water reactors.

    PubMed

    Kim, Hee Geun; Kong, Tae Young

    2012-12-01

    In general, internal exposure from tritium at pressurised heavy water reactors (PHWRs) accounts for ∼20-40 % of the total radiation dose. Tritium usually reaches the equilibrium concentration after a few hours inside the body and is then excreted from the body with an effective half-life in the order of 10 d. In this study, tritium metabolism was reviewed using its excretion rate in urine samples of workers at Korean PHWRs. The tritium concentration in workers' urine samples was also measured as a function of time after intake. On the basis of the monitoring results, changes in the tritium concentration inside the body were then analysed.

  10. Label Distribution in Tissues of Wheat Seedlings Cultivated with Tritium-Labeled Leonardite Humic Acid

    PubMed Central

    Kulikova, Natalia A.; Abroskin, Dmitry P.; Badun, Gennady A.; Chernysheva, Maria G.; Korobkov, Viktor I.; Beer, Anton S.; Tsvetkova, Eugenia A.; Senik, Svetlana V.; Klein, Olga I.; Perminova, Irina V.

    2016-01-01

    Humic substances (HS) play important roles in the biotic-abiotic interactions of the root plant and soil contributing to plant adaptation to external environments. However, their mode of action on plants remains largely unknown. In this study the HS distribution in tissues of wheat seedlings was examined using tritium-labeled humic acid (HA) derived from leonardite (a variety of lignites) and microautoradiography (MAR). Preferential accumulation of labeled products from tritiated HA was found in the roots as compared to the shoots, and endodermis was shown to be the major control point for radial transport of label into vascular system of plant. Tritium was also found in the stele and xylem tissues indicating that labeled products from tritiated HA could be transported to shoot tissues via the transpiration stream. Treatment with HA lead to an increase in the content of polar lipids of photosynthetic membranes. The observed accumulation of labeled HA products in root endodermis and positive impact on lipid synthesis are consistent with prior reported observations on physiological effects of HS on plants such as enhanced growth and development of lateral roots and improvement/repairs of the photosynthetic status of plants under stress conditions. PMID:27350412

  11. Label Distribution in Tissues of Wheat Seedlings Cultivated with Tritium-Labeled Leonardite Humic Acid

    NASA Astrophysics Data System (ADS)

    Kulikova, Natalia A.; Abroskin, Dmitry P.; Badun, Gennady A.; Chernysheva, Maria G.; Korobkov, Viktor I.; Beer, Anton S.; Tsvetkova, Eugenia A.; Senik, Svetlana V.; Klein, Olga I.; Perminova, Irina V.

    2016-06-01

    Humic substances (HS) play important roles in the biotic-abiotic interactions of the root plant and soil contributing to plant adaptation to external environments. However, their mode of action on plants remains largely unknown. In this study the HS distribution in tissues of wheat seedlings was examined using tritium-labeled humic acid (HA) derived from leonardite (a variety of lignites) and microautoradiography (MAR). Preferential accumulation of labeled products from tritiated HA was found in the roots as compared to the shoots, and endodermis was shown to be the major control point for radial transport of label into vascular system of plant. Tritium was also found in the stele and xylem tissues indicating that labeled products from tritiated HA could be transported to shoot tissues via the transpiration stream. Treatment with HA lead to an increase in the content of polar lipids of photosynthetic membranes. The observed accumulation of labeled HA products in root endodermis and positive impact on lipid synthesis are consistent with prior reported observations on physiological effects of HS on plants such as enhanced growth and development of lateral roots and improvement/repairs of the photosynthetic status of plants under stress conditions.

  12. Secondary Startup Neutron Sources as a Source of Tritium in a Pressurized Water Reactor (PWR) Reactor Coolant System (RCS)

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

    Shaver, Mark W.; Lanning, Donald D.

    2010-02-01

    The hypothesis of this paper is that the Zircaloy clad fuel source is minimal and that secondary startup neutron sources are the significant contributors of the tritium in the RCS that was previously assigned to release from fuel. Currently there are large uncertainties in the attribution of tritium in a Pressurized Water Reactor (PWR) Reactor Coolant System (RCS). The measured amount of tritium in the coolant cannot be separated out empirically into its individual sources. Therefore, to quantify individual contributors, all sources of tritium in the RCS of a PWR must be understood theoretically and verified by the sum ofmore » the individual components equaling the measured values.« less

  13. 2014 Accomplishments-Tritium aging studies on stainless steel: Fracture toughness properties of forged stainless steels-Effect of hydrogen, forging strain rate, and forging temperature

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

    Morgan, Michael J.

    Forged stainless steels are used as the materials of construction for tritium reservoirs. During service, tritium diffuses into the reservoir walls and radioactively decays to helium-3. Tritium and decay helium cause a higher propensity for cracking which could lead to a tritium leak or delayed failure of a tritium reservoir. The factors that affect the tendency for crack formation and propagation include: Environment; steel type and microstructure; and, vessel configuration (geometry, pressure, residual stress). Fracture toughness properties are needed for evaluating the long-term effects of tritium on their structural properties. Until now, these effects have been characterized by measuring themore » effects of tritium on the tensile and fracture toughness properties of specimens fabricated from experimental forgings in the form of forward-extruded cylinders. A key result of those studies is that the long-term cracking resistance of stainless steels in tritium service depends greatly on the interaction between decay helium and the steels’ forged microstructure. New experimental research programs are underway and are designed to measure tritium and decay helium effects on the cracking properties of stainless steels using actual tritium reservoir forgings instead of the experimental forgings of past programs. The properties measured should be more representative of actual reservoir properties because the microstructure of the specimens tested will be more like that of the tritium reservoirs. The programs are designed to measure the effects of key forging variables on tritium compatibility and include three stainless steels, multiple yield strengths, and four different forging processes. The effects on fracture toughness of hydrogen and crack orientation were measured for type 316L forgings. In addition, hydrogen effects on toughness were measured for Type 304L block forgings having two different yield strengths. Finally, fracture toughness properties of type

  14. Hydrogeology and tritium transport in Chicken Creek Canyon,Lawrence Berkeley National Laboratory, Berkeley, California

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

    Jordan, Preston D.; Javandel, Iraj

    This study of the hydrogeology of Chicken Creek Canyon wasconducted by the Environmental Restoration Program (ERP) at LawrenceBerkeley National Laboratory (LBNL). This canyon extends downhill fromBuilding 31 at LBNL to Centennial Road below. The leading edge of agroundwater tritium plume at LBNL is located at the top of the canyon.Tritium activities measured in this portion of the plume during thisstudy were approximately 3,000 picocuries/liter (pCi/L), which issignificantly less than the maximum contaminant level (MCL) for drinkingwaterof 20,000 pCi/L established by the Environmental ProtectionAgency.There are three main pathways for tritium migration beyond theLaboratory s boundary: air, surface water and groundwater flow.more » Thepurpose of this report is to evaluate the groundwater pathway.Hydrogeologic investigation commenced with review of historicalgeotechnical reports including 35 bore logs and 27 test pit/trench logsas well as existing ERP information from 9 bore logs. This was followedby field mapping of bedrock outcrops along Chicken Creek as well asbedrock exposures in road cuts on the north and east walls of the canyon.Water levels and tritium activities from 6 wells were also considered.Electrical-resistivity profiles and cone penetration test (CPT) data werecollected to investigate the extent of an interpreted alluvial sandencountered in one of the wells drilled in this area. Subsequent loggingof 7 additional borings indicated that this sand was actually anunusually well-sorted and typically deeply weathered sandstone of theOrinda Formation. Wells were installed in 6 of the new borings to allowwater level measurement and analysis of groundwater tritium activity. Aslug test and pumping tests were also performed in the wellfield.« less

  15. High efficiency 4H-SiC betavoltaic power sources using tritium radioisotopes

    NASA Astrophysics Data System (ADS)

    Thomas, Christopher; Portnoff, Samuel; Spencer, M. G.

    2016-01-01

    Realization of an 18.6% efficient 4H-silicon carbide (4H-SiC) large area betavoltaic power source using the radioisotope tritium is reported. A 200 nm 4H-SiC P+N junction is used to collect high-energy electrons. The electron source is a titanium tritide (TiH3x) foil, or an integrated titanium tritide region formed by the diffusion of tritium into titanium. The specific activity of the source is directly measured. Dark current measured under short circuit conditions was less than 6.1 pA/cm2. Samples measured with an external tritium foil produced an open circuit voltage of 2.09 V, short circuit current of 75.47 nA/cm2, fill factor of 0.86, and power efficiency of 18.6%. Samples measured with an integrated source produced power efficiencies of 12%. Simulations were done to determine the beta spectrum (modified by self absorption) exiting the source and the electron hole pair generation function in the 4H-SiC. The electron-hole pair generation function in 4H-SiC was modeled as a Gaussian distribution, and a closed form solution of the continuity equation was used to analyze the cell performance. The effective surface recombination velocity in our samples was found to be 105-106 cm/s. Our analysis demonstrated that the surface recombination dominates the performance of a tritium betavoltaic device but that using a thin P+N junction structure can mitigate some of the negative effects.

  16. Combustion method for assay of biological materials labeled with carbon-14 or tritium, or double-labeled

    NASA Technical Reports Server (NTRS)

    Huebner, L. G.; Kisieleski, W. E.

    1969-01-01

    Dry catalytic combustion at high temperatures is used for assaying biological materials labeled carbon-14 and tritium, or double-labeled. A modified oxygen-flask technique is combined with standard vacuum-line techniques and includes convenience of direct in-vial collection of final combustion products, giving quantitative recovery of tritium and carbon-14.

  17. Cryogenic tritium-hydrogen-deuterium and deuterium-tritium layer implosions with high density carbon ablators in near-vacuum hohlraums

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

    Meezan, N. B., E-mail: meezan1@llnl.gov; Hopkins, L. F. Berzak; Pape, S. Le

    2015-06-15

    High Density Carbon (or diamond) is a promising ablator material for use in near-vacuum hohlraums, as its high density allows for ignition designs with laser pulse durations of <10 ns. A series of Inertial Confinement Fusion (ICF) experiments in 2013 on the National Ignition Facility [Moses et al., Phys. Plasmas 16, 041006 (2009)] culminated in a deuterium-tritium (DT) layered implosion driven by a 6.8 ns, 2-shock laser pulse. This paper describes these experiments and comparisons with ICF design code simulations. Backlit radiography of a tritium-hydrogen-deuterium (THD) layered capsule demonstrated an ablator implosion velocity of 385 km/s with a slightly oblate hot spot shape.more » Other diagnostics suggested an asymmetric compressed fuel layer. A streak camera-based hot spot self-emission diagnostic (SPIDER) showed a double-peaked history of the capsule self-emission. Simulations suggest that this is a signature of low quality hot spot formation. Changes to the laser pulse and pointing for a subsequent DT implosion resulted in a higher temperature, prolate hot spot and a thermonuclear yield of 1.8 × 10{sup 15} neutrons, 40% of the 1D simulated yield.« less

  18. Movement of a tritium plume in shallow groundwater at a legacy low-level radioactive waste disposal site in eastern Australia.

    PubMed

    Hughes, C E; Cendón, D I; Harrison, J J; Hankin, S I; Johansen, M P; Payne, T E; Vine, M; Collins, R N; Hoffmann, E L; Loosz, T

    2011-10-01

    Between 1960 and 1968 low-level radioactive waste was buried in a series of shallow trenches near the Lucas Heights facility, south of Sydney, Australia. Groundwater monitoring carried out since the mid 1970s indicates that with the exception of tritium, no radioactivity above typical background levels has been detected outside the immediate vicinity of the trenches. The maximum tritium level detected in ground water was 390 kBq/L and the median value was 5400 Bq/L, decay corrected to the time of disposal. Since 1968, a plume of tritiated water has migrated from the disposal trenches and extends at least 100 m from the source area. Tritium in rainfall is negligible, however leachate from an adjacent and fill represents a significant additional tritium source. Study data indicate variation in concentration levels and plume distribution in response to wet and dry climatic periods and have been used to determine pathways for tritium migration through the subsurface.

  19. Incorporation of negative rules and evolution of a fuzzy controller for yeast fermentation process.

    PubMed

    Birle, Stephan; Hussein, Mohamed Ahmed; Becker, Thomas

    2016-08-01

    The control of bioprocesses can be very challenging due to the fact that these kinds of processes are highly affected by various sources of uncertainty like the intrinsic behavior of the used microorganisms. Due to the reason that these kinds of process uncertainties are not directly measureable in most cases, the overall control is either done manually because of the experience of the operator or intelligent expert systems are applied, e.g., on the basis of fuzzy logic theory. In the latter case, however, the control concept is mainly represented by using merely positive rules, e.g., "If A then do B". As this is not straightforward with respect to the semantics of the human decision-making process that also includes negative experience in form of constraints or prohibitions, the incorporation of negative rules for process control based on fuzzy logic is emphasized. In this work, an approach of fuzzy logic control of the yeast propagation process based on a combination of positive and negative rules is presented. The process is guided along a reference trajectory for yeast cell concentration by alternating the process temperature. The incorporation of negative rules leads to a much more stable and accurate control of the process as the root mean squared error of reference trajectory and system response could be reduced by an average of 62.8 % compared to the controller using only positive rules.

  20. Thermal enhancement cartridge heater modified (TECH Mod) tritium hydride bed development, Part 1 - Design and fabrication

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

    Klein, J.E.; Estochen, E.G.

    The Savannah River Site (SRS) tritium facilities have used first generation (Gen1) LaNi{sub 4.25}Al{sub 0.75} (LANA0.75) metal hydride storage beds for tritium absorption, storage, and desorption. The Gen1 design utilizes hot and cold nitrogen supplies to thermally cycle these beds. Second and third generation (Gen2 and Gen3) storage bed designs include heat conducting foam and divider plates to spatially fix the hydride within the bed. For thermal cycling, the Gen2 and Gen3 beds utilize internal electric heaters and glovebox atmosphere flow over the bed inside the bed external jacket for cooling. The currently installed Gen1 beds require replacement due tomore » tritium aging effects on the LANA0.75 material, and cannot be replaced with Gen2 or Gen3 beds due to different designs of these beds. At the end of service life, Gen1 bed desorption efficiencies are limited by the upper temperature of hot nitrogen supply. To increase end-of-life desorption efficiency, the Gen1 bed design was modified, and a Thermal Enhancement Cartridge Heater Modified (TECH Mod) bed was developed. Internal electric cartridge heaters in the new design to improve end-of-life desorption, and also permit in-bed tritium accountability (IBA) calibration measurements to be made without the use of process tritium. Additional enhancements implemented into the TECH Mod design are also discussed. (authors)« less

  1. THERMAL ENHANCEMENT CARTRIDGE HEATER MODIFIED TECH MOD TRITIUM HYDRIDE BED DEVELOPMENT PART I DESIGN AND FABRICATION

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

    Klein, J.; Estochen, E.

    The Savannah River Site (SRS) tritium facilities have used 1{sup st} generation (Gen1) LaNi{sub 4.25}Al{sub 0.75} (LANA0.75) metal hydride storage beds for tritium absorption, storage, and desorption. The Gen1 design utilizes hot and cold nitrogen supplies to thermally cycle these beds. Second and 3{sup rd} generation (Gen2 and Gen3) storage bed designs include heat conducting foam and divider plates to spatially fix the hydride within the bed. For thermal cycling, the Gen2 and Gen 3 beds utilize internal electric heaters and glovebox atmosphere flow over the bed inside the bed external jacket for cooling. The currently installed Gen1 beds requiremore » replacement due to tritium aging effects on the LANA0.75 material, and cannot be replaced with Gen2 or Gen3 beds due to different designs of these beds. At the end of service life, Gen1 bed desorption efficiencies are limited by the upper temperature of hot nitrogen supply. To increase end-of-life desorption efficiency, the Gen1 bed design was modified, and a Thermal Enhancement Cartridge Heater Modified (TECH Mod) bed was developed. Internal electric cartridge heaters in the new design to improve end-of-life desorption, and also permit in-bed tritium accountability (IBA) calibration measurements to be made without the use of process tritium. Additional enhancements implemented into the TECH Mod design are also discussed.« less

  2. Optimization of tritium breeding and shielding analysis to plasma in ITER fusion reactor

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

    Indah Rosidah, M., E-mail: indah.maymunah@gmail.com; Suud, Zaki, E-mail: szaki@fi.itb.ac.id; Yazid, Putranto Ilham

    The development of fusion energy is one of the important International energy strategies with the important milestone is ITER (International Thermonuclear Experimental Reactor) project, initiated by many countries, such as: America, Europe, and Japan who agreed to set up TOKAMAK type fusion reactor in France. In ideal fusion reactor the fuel is purely deuterium, but it need higher temperature of reactor. In ITER project the fuels are deuterium and tritium which need lower temperature of the reactor. In this study tritium for fusion reactor can be produced by using reaction of lithium with neutron in the blanket region. With themore » tritium breeding blanket which react between Li-6 in the blanket with neutron resulted from the plasma region. In this research the material used in each layer surrounding the plasma in the reactor is optimized. Moreover, achieving self-sufficiency condition in the reactor in order tritium has enough availability to be consumed for a long time. In order to optimize Tritium Breeding Ratio (TBR) value in the fusion reactor, there are several strategies considered here. The first requirement is making variation in Li-6 enrichment to be 60%, 70%, and 90%. But, the result of that condition can not reach TBR value better than with no enrichment. Because there is reduction of Li-7 percent when increasing Li-6 percent. The other way is converting neutron multiplier material with Pb. From this, we get TBR value better with the Be as neutron multiplier. Beside of TBR value, fusion reactor can analyze the distribution of neutron flux and dose rate of neutron to know the change of neutron concentration for each layer in reactor. From the simulation in this study, 97% neutron concentration can be absorbed by material in reactor, so it is good enough. In addition, it is required to analyze spectrum neutron energy in many layers in the fusion reactor such as in blanket, coolant, and divertor. Actually material in that layer can resist in high

  3. High efficiency 4H-SiC betavoltaic power sources using tritium radioisotopes

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

    Thomas, Christopher; Portnoff, Samuel; Spencer, M. G.

    Realization of an 18.6% efficient 4H-silicon carbide (4H-SiC) large area betavoltaic power source using the radioisotope tritium is reported. A 200 nm 4H-SiC P{sup +}N junction is used to collect high-energy electrons. The electron source is a titanium tritide (TiH{sup 3}{sub x}) foil, or an integrated titanium tritide region formed by the diffusion of tritium into titanium. The specific activity of the source is directly measured. Dark current measured under short circuit conditions was less than 6.1 pA/cm{sup 2}. Samples measured with an external tritium foil produced an open circuit voltage of 2.09 V, short circuit current of 75.47 nA/cm{sup 2}, fill factor of 0.86,more » and power efficiency of 18.6%. Samples measured with an integrated source produced power efficiencies of 12%. Simulations were done to determine the beta spectrum (modified by self absorption) exiting the source and the electron hole pair generation function in the 4H-SiC. The electron-hole pair generation function in 4H-SiC was modeled as a Gaussian distribution, and a closed form solution of the continuity equation was used to analyze the cell performance. The effective surface recombination velocity in our samples was found to be 10{sup 5}–10{sup 6 }cm/s. Our analysis demonstrated that the surface recombination dominates the performance of a tritium betavoltaic device but that using a thin P{sup +}N junction structure can mitigate some of the negative effects.« less

  4. Differential atmospheric tritium sampler

    DOEpatents

    Griesbach, O.A.; Stencel, J.R.

    1987-10-02

    An atmospheric tritium sampler is provided which uses a carrier gas comprised of hydrogen gas and a diluting gas, mixed in a nonexplosive concentration. Sample air and carrier gas are drawn into and mixed in a manifold. A regulator meters the carrier gas flow to the manifold. The air sample/carrier gas mixture is pulled through a first moisture trap which adsorbs water from the air sample. The moisture then passes through a combustion chamber where hydrogen gas in the form of H/sub 2/ or HT is combusted into water. The manufactured water is transported by the air stream to a second moisture trap where it is adsorbed. The air is then discharged back into the atmosphere by means of a pump.

  5. Differential atmospheric tritium sampler

    DOEpatents

    Griesbach, Otto A.; Stencel, Joseph R.

    1990-01-01

    An atmospheric tritium sampler is provided which uses a carrier gas comprised of hydrogen gas and a diluting gas, mixed in a nonexplosive concentration. Sample air and carrier gas are drawn into and mixed in a manifold. A regulator meters the carrier gas flow to the manifold. The air sample/carrier gas mixture is pulled through a first moisture trap which adsorbs water from the air sample. The mixture then passes through a combustion chamber where hydrogen gas in the form of H.sub.2 or HT is combusted into water. The manufactured water is transported by the air stream to a second moisture trap where it is adsorbed. The air is then discharged back into the atmosphere by means of a pump.

  6. Evaluation of Hydrogen Isotope Exchange Methodology on Adsorbents for Tritium Removal

    DOE PAGES

    Morgan, Gregg A.; Xiao, S. Xin

    2015-03-06

    The Savannah River National Laboratory has demonstrated a potential process that can be used to remove tritium from tritiated water using Pt-catalyzed molecular sieves. The process is an elemental isotope exchange process in which H 2 (when flowed through the molecular sieves) will exchange with the adsorbed water, D 2O, leaving H 2O adsorbed on the molecular sieves. Various formulations of catalyzed molecular sieve material were prepared using two different techniques, Pt-implantation and Pt-ion exchange. This technology has been demonstrated for a protium (H) and deuterium (D) system, but can also be used for the removal of tritium from contaminatedmore » water (T 2O, HTO, and DTO) using D 2 (or H 2)« less

  7. An overview of organically bound tritium experiments in plants following a short atmospheric HTO exposure.

    PubMed

    Galeriu, D; Melintescu, A; Strack, S; Atarashi-Andoh, M; Kim, S B

    2013-04-01

    The need for a less conservative, but reliable risk assessment of accidental tritium releases is emphasized in the present debate on the nuclear energy future. The development of a standard conceptual model for accidental tritium releases must be based on the process level analysis and the appropriate experimental database. Tritium transfer from atmosphere to plants and the subsequent conversion into organically bound tritium (OBT) strongly depends on the plant characteristics, seasons, and meteorological conditions, which have a large variability. The present study presents an overview of the relevant experimental data for the short term exposure, including the unpublished information, also. Plenty of experimental data is provided for wheat, rice, and soybean and some for potato, bean, cherry tomato, radish, cabbage, and tangerine as well. Tritiated water (HTO) uptake by plants during the daytime and nighttime has an important role in further OBT synthesis. OBT formation in crops depends on the development stage, length, and condition of exposure. OBT translocation to the edible plant parts differs between the crops analyzed. OBT formation during the nighttime is comparable with that during the daytime. The present study is a preliminary step for the development of a robust model of crop contamination after an HTO accidental release. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Scintillation imaging of tritium radioactivity distribution during tritiated thymidine uptake by PC12 cells using a melt-on scintillator.

    PubMed

    Irikura, Namiko; Miyoshi, Hirokazu; Shinohara, Yasuo

    2017-02-01

    A scintillation image of tritium fixed in a melt-on scintillator was obtained using a charged-coupled device (CCD) imager, and a linear relationship was observed between the intensity of the scintillation image and the radioactivity of tritium. In a [ 3 H]thymidine uptake experiment, a linear correlation between the intensity of the CCD image and the dilution ratio of cells was confirmed. Scintillation imaging has the potential for use in direct observation of tritium radioactivity distribution. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Controllability and Optimal Harvesting of a Prey-Predator Model Incorporating a Prey Refuge

    ERIC Educational Resources Information Center

    Kar, Tapan Kumar

    2006-01-01

    This paper deals with a prey-predator model incorporating a prey refuge and harvesting of the predator species. A mathematical analysis shows that prey refuge plays a crucial role for the survival of the species and that the harvesting effort on the predator may be used as a control to prevent the cyclic behaviour of the system. The optimal…

  10. Aptamer-incorporated hydrogels for visual detection, controlled drug release, and targeted cancer therapy

    PubMed Central

    Liu, Jun; Kang, Huaizhi; Donovan, Michael; Zhu, Zhi

    2017-01-01

    Hydrogels are water-retainable materials, made from cross-linked polymers, that can be tailored to applications in bioanalysis and biomedicine. As technology advances, an increasing number of molecules have been used as the components of hydrogel systems. However, the shortcomings of these systems have prompted researchers to find new materials that can be incorporated into them. Among all of these emerging materials, aptamers have recently attracted substantial attention because of their unique properties, for example biocompatibility, selective binding, and molecular recognition, all of which make them promising candidates for target-responsive hydrogel engineering. In this work, we will review how aptamers have been incorporated into hydrogel systems to enable colorimetric detection, controlled drug release, and targeted cancer therapy. PMID:22052153

  11. Preparation of a deuterated polymer: Simulating to produce a solid tritium radioactive source

    NASA Astrophysics Data System (ADS)

    Hu, Rui; Kan, Wentao; Xiong, Xiaoling; Wei, Hongyuan

    2017-08-01

    The preparation of a deuterated polymer was performed in order to simulate the production of the corresponding tritiated polymer as a solid tritium radioactive source. Substitution and addition reaction were used to introduce deuterium into the polymer. Proton nuclear magnetic resonance and FT-IR spectroscopy were used to investigate the extent and location of deuterium in the polymer, indicating an effectively deuterated polymer was produced. The thermal analysis showed that the final polymer product could tolerate the environmental temperature below 125 °C in its application. This research provides a prosperous method to prepare solid tritium radioactive source.

  12. Environmental tritium and radiocarbon studies in the Vedavati River basin, Karnataka and Andhra Pradesh, India

    NASA Astrophysics Data System (ADS)

    Sukhija, B. S.; Achutha Rao, A.

    1983-01-01

    Environmental tritium and radiocarbon studies were undertaken in the Vedavati river basin situated partly in Karnataka and partly in Andhra Pradesh, India, aimed at the determination of the general recharge condition of the water-bearing zones in the gneissic complex, granites and the Dharwar Group of metamorphic rocks, where groundwater occurs under semi-unconfined to semi-confined conditions and at places under the water-table condition. The groundwater movement is controlled by fractures, fissures, a weathered zone and surficial mantle. An attempt was also made to find out whether substantial recharge occurs along fractured lineaments; whether the water-bearing zones can be considered as interconnected or isolated, and whether the recharge and discharge areas identified by geohydrological considerations can be confirmed. Environmental tritium and radiocarbon contents, measured in ˜ 45 groundwater samples, show that a large number of samples are very young, containing water from post-thermonuclear-era rain, thus indicating an age less than 25 yr. In some other samples, despite radiocarbon ages found to be older, some component of recent precipitation is found to be present as indicated by bomb tritium. Groundwater dating in the area shows an excellent correlation between hydro-isochrons of minimum age with the recharge contour of maximum magnitude. This study has clearly resulted in the demarcation of the recharge areas. However, the discharge areas as such cannot be clearly delineated because of lack of a pattern indicating increase of ages in any particular direction. This, however, also reflects somewhat discontinuous groundwater bodies, which may also be expected from the general structure and hydrogeology of the region. Along a major lineament the groundwater is found to be very young thus confirming that substantial recharge occurs along lineaments.

  13. REVIEWS OF TOPICAL PROBLEMS: Helium-isotope mass-spectrometric method for studying tritium beta decay (idea, experiment, nuclear and molecular physics applications)

    NASA Astrophysics Data System (ADS)

    Akulov, Yuii A.; Mamyrin, Boris A.

    2003-11-01

    Experimental data on the variation of tritium nucleus beta decay constant caused by the interaction of the resulting beta-electron with orbital electrons and shell vacancies are reviewed for free atomic tritium and molecular tritium and used to obtain the half-life of atomic tritium (T1/2)a=(12.264±0.018) y, the half-life of the free triton (T1/2)t=(12.238±0.020) y, the axial-vector-to-vector weak-interaction coupling constant ratio (GA/GV)t=-1.2646 ± 0.0035 for beta decay of the triton, and an independent estimate of the free neutron lifetime τn= (890.3 ± 3.9stat ± 1.4syst) s.

  14. Environmental Testing of Tritium-Phosphor Glass Vials for Use in Long-Life Radioisotope Power Conversion Units

    NASA Technical Reports Server (NTRS)

    Zemcov, Michael; Cardona, Pedro; Parkus, James; Patru, Dorin; Yost, Valerie

    2017-01-01

    Power generation in extreme environments, such as the outer solar system, the night side of planets, or other low-illumination environments, currently presents a technology gap that challenges NASA's ambitious scientific goals. We are developing a radioisotope power cell (RPC) that utilizes commercially available tritium light sources and standard 1.85 eV InGaP2 photovoltaic cells to convert beta particle energy to electric energy. In the test program described here, we perform environmental tests on commercially available borosilicate glass vials internally coated with a ZnS luminescent phosphor that are designed to contain gaseous tritium in our proposed power source. Such testing is necessary to ensure that the glass containing the radioactive tritium is capable of withstanding the extreme environments of launch and space for extended periods of time.

  15. Environmental studies in Antarctica on the basis of tritium and radiocarbon measurements.

    PubMed

    Hebert, Detlef; Fröhlich, Klaus

    2011-09-01

    In 1975 and 1977, samples from snow, firn, atmospheric CO(2), plants, and penguin guano were collected near the Soviet Antarctic research station Molodezhnaya. The results of tritium, deuterium, oxygen-18, (13)C, and (14)C measurements are discussed. From the tritium, deuterium, and (18)O measurement results of a firn profile at the Hays glacier, a value of the accumulation rate of 30 g water per cm 2 and year could be evaluated. By means of (14)C dating, the age of penguin breeding places was determined to be 1500 ± 500 years. (14)C data from atmospheric CO(2) and plants are discussed in terms of the age of the plants.

  16. Evaluation of hydrogen isotope exchange methodology on adsorbents for tritium removal

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

    Morgan, G.A.; Xin Xiao, S.

    2015-03-15

    The Savannah River National Laboratory has demonstrated a potential process that can be used to remove tritium from tritiated water using Pt-catalyzed molecular sieves. The process is an elemental isotope exchange process in which H{sub 2} (when flowed through the molecular sieves) will exchange with the adsorbed water, D{sub 2}O, leaving H{sub 2}O adsorbed on the molecular sieves. Various formulations of catalyzed molecular sieve material were prepared using two different techniques, Pt-implantation and Pt-ion exchange. This technology has been demonstrated for a protium (H) and deuterium (D) system, but can also be used for the removal of tritium from contaminatedmore » water (T{sub 2}O, HTO, and DTO) using D{sub 2} (or H{sub 2}). (authors)« less

  17. Use of environmental tritium to characterize ground water flow systems in regolith and crystalline fractured-rock hydrogeologic settings

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

    Stewart, L.M.; Rose, S.E.

    1993-03-01

    Environmental tritium concentrations measured in 84 ground-water, surface-water, and precipitation samples collected throughout the Piedmont and Blue Ridge physiographic provinces of northern Georgia were used in conjunction with available geological and hydrochemical data to develop general concepts of ground-water flow within a regolith and crystalline fractured-rock system. Tritium concentrations ranged from 0 tritium units (TU) in water sampled from unpumped wells completed in fractured bedrock to 34 TU in water sampled from pumped wells screened at various intervals within the overlying regolith. Tritium concentrations measured in spring discharge, streamflow, and precipitation also were within this range. The distribution of tritiummore » indicates that tritiated water is retained within the regolith and that pumping is an important mechanism for mixing water of different ages within the flow system. Simulations using an analytical mixing model were performed to estimate the degree of mixing and the residence time of ground water within the flow system. Results of the simulations compared favorably with other geological and hydrochemical data. Simulated residence times for tritiated water indicated that ground-water residence times may be greater than 37 years within the bedrock fractures, but as little as 15 years in pumped bedrock wells and streams. Estimates of ground-water ages were based on environmental tritium concentrations produced by thermonuclear bomb testing conducted during the years of 1961-1962.« less

  18. Longitudinal Stability and Control Characteristics of a B-29 Airplane with a Booster Incorporated in the Elevator Control System to Provide Various Stick-Force and Control-Rate Characteristics

    NASA Technical Reports Server (NTRS)

    Mathews, Charles W.; Talmage, Donald B.; Whitten, James B.

    1948-01-01

    The longitudinal stability and control characteristics of a B-29 airplane have been measured with a booster incorporated in the elevator control system. Tests were made to determine the effects on the handling qualities of the test airplane of variations in pilots control-force gradients as well as the effects of variations in the maximum rate of control motion supplied by the booster system.

  19. EFFECTS OF ONE WEEK TRITIUM EXPOSURE ON EPDM ELASTOMER

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

    Clark, E

    This report documents test results for the exposure of four formulations of EPDM (ethylene-propylene diene monomer) elastomer to tritium gas at one atmosphere for approximately one week and characterization of material property changes and changes to the exposure gas during exposure. All EPDM samples were provided by Los Alamos National Laboratory (LANL). Material properties that were characterized include mass, sample dimensions, appearance, flexibility, and dynamic mechanical properties. The glass transition temperature was determined by analysis of the dynamic mechanical property data per ASTM standards. No change of glass transition temperature due to the short tritium gas exposure was observed. Filledmore » and unfilled formulations of Dupont{reg_sign} Nordel{trademark} 1440 had a slightly higher glass transition temperature than filled and unfilled formulations of Uniroyal{reg_sign} Royalene{reg_sign} 580H; filled formulations had the same glass transition as unfilled. The exposed samples appeared the same as before exposure--there was no evidence of discoloration, and no residue on stainless steel spacers contacting the samples during exposure was observed. The exposed samples remained flexible--all formulations passed a break test without failing. The unique properties of polymers make them ideal for certain components in gas handling systems. Specifically, the resiliency of elastomers is ideal for sealing surfaces, for example in valves. EPDM, initially developed in the 1960s, is a hydrocarbon polymer used extensively for sealing applications. EPDM is used for its excellent combination of properties including high/low-temperature resistance, radiation resistance, aging resistance, and good mechanical properties. This report summarizes initial work to characterize effects of tritium gas exposure on samples of four types of EPDM elastomer: graphite filled and unfilled formulations of Nordel{trademark} 1440 and Royalene{reg_sign} 580H.« less

  20. Simple system for measuring tritium Ad/absorption using a 2. pi. counter and thermal desorption spectrometer

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

    Miyake, H.; Matsuyama, M.; Watanabe, K.

    1992-03-01

    In this paper, the authors develop a simple system using tritium tracer and thermal desorption techniques to measure the tritium adsorption and/or absorption on/in a material having typical surface conditions: namely, not cleaned surface. The tritium counting devices used were a 2{pi} counter and conventional proportional counter. With this system, the amounts of ad/absorption could be measured without exposing the samples to air after exposing them to tritium gas. The overall efficiency (F) of the 2{pi} counter was described at F = exp({minus}2.64h), where h is the distance from the sample to the detector. Ad/absorption measurements were carried out formore » several materials used for fabricating conventional vacuum systems. The results were, in the order of decreasing amounts of ad/absorption, as (fiber reinforced plastics(FRP)) {gt} (nickel(Ni), molybdenum disulfide(MoS{sub 2})) {gt} (stainless steel (SS304), iron(Fe), aluminum alloy(A2219)) {gt} (boron nitride(h-BN), silicon carbide (SiC), SS304 passivated by anodic oxidation layers(ASS) and that by boron nitride segregation layers (BSS)). The relative amounts were abut 100 for Ni and 0.1 for ASS and BSS, being normalized to Fe = 1.« less

  1. Neutron yield when fast deuterium ions collide with strongly charged tritium-saturated dust particles

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

    Akishev, Yu. S., E-mail: akishev@triniti.ru; Karal’nik, V. B.; Petryakov, A. V.

    2017-02-15

    The ultrahigh charging of dust particles in a plasma under exposure to an electron beam with an energy up to 25 keV and the formation of a flux of fast ions coming from the plasma and accelerating in the strong field of negatively charged particles are considered. Particles containing tritium or deuterium atoms are considered as targets. The calculated rates of thermonuclear fusion reactions in strongly charged particles under exposure to accelerated plasma ions are presented. The neutron generation rate in reactions with accelerated deuterium and tritium ions has been calculated for these targets. The neutron yield has been calculatedmore » when varying the plasma-forming gas pressure, the plasma density, the target diameter, and the beam electron current density. Deuterium and tritium-containing particles are shown to be the most promising plasmaforming gas–target material pair for the creation of a compact gas-discharge neutron source based on the ultrahigh charging of dust particles by beam electrons with an energy up to 25 keV.« less

  2. Tracking different freshwater plumes at the Bay of Biscay scale by using a dissolved radioactive tracer: tritium (HTO)

    NASA Astrophysics Data System (ADS)

    Oms, Pierre-Emmanuel; Bailly du Bois, Pascal; Dumas, Franck; Lazure, Pascal; Morillon, Mehdi; Solier, Luc; Voiseux, Claire; Le Corre, Cédric; Maire, Donovan

    2017-04-01

    New measurements of a radioactive tracer (tritium) on the whole continental shelf of the Bay of Biscay during several oceanographic campaigns between 2008 and 2016 allow comparison with results of the plume dispersion from the regional circulation model, MARS3D (Lazure and Dumas, 2008). Seaward dispersion of freshwater in the Bay of Biscay is highly variable in time and depends on many processes like tide, wind, freshwater runoff or water mass stratification. Until now salinity was a useful tracer to describe dispersion of freshwater, but the complexity to account for these different sources require an additional conservative tracer. Tritium (3H) is a radionuclide tracer released as HTO in the Bay of Biscay by nuclear power plant through two French rivers, Loire and Gironde. Tritium inflow from Loire and Gironde are well known thanks to plants operator data and an effort of daily measurements. Indeed an automated and daily integrated sampling system is deployed in the Loire River and the Gironde Estuary. These plumes are clearly detectable over the continental shelf despite very low tritium concentrations (0.05 - 0.5 Bq/L, 0.5 - 5 TU). In order to determine such low tritium concentrations in the Bay of Biscay, we use a mass spectrometer to measure the 3He (gas) produced by radioactive disintegration of tritium after 3He ingrowth (1 - 6 months). The aim of this work is to describes and quantify the dispersion processes occurring in the continental shelf according to seasons. Thanks to assessments of the model dispersion compared to in-situ measurements, quantification of the residential time of freshwater in the continental shelf as well as quantification of their transfer from continental shelf to abyssal plain is possible. The 3H/S ratio will allow an estimation of respective inputs from Loire and Gironde in the bay.

  3. Human Health and the Biological Effects of Tritium in Drinking Water: Prudent Policy Through Science - Addressing the ODWAC New Recommendation.

    PubMed

    Dingwall, S; Mills, C E; Phan, N; Taylor, K; Boreham, D R

    2011-02-22

    Tritium is a radioactive form of hydrogen and is a by-product of energy production in Canadian Deuterium Uranium (CANDU) reactors. The release of this radioisotope into the environment is carefully managed at CANDU facilities in order to minimize radiation exposure to the public. However, under some circumstances, small accidental releases to the environment can occur. The radiation doses to humans and non-human biota from these releases are low and orders of magnitude less than doses received from naturally occurring radioisotopes or from manmade activities, such as medical imaging and air travel. There is however a renewed interest in the biological consequences of low dose tritium exposures and a new limit for tritium levels in Ontario drinking water has been proposed. The Ontario Drinking Water Advisory Council (ODWAC) issued a formal report in May 2009 in response to a request by the Minister of the Environment, concluding that the Ontario Drinking Water Quality Standard for tritium should be revised from the current 7,000 Bq/L level to a new, lower 20 Bq/L level. In response to this recommendation, an international scientific symposium was held at McMaster University to address the issues surrounding this change in direction and the validity of a new policy. Scientists, regulators, government officials, and industrial stakeholders were present to discuss the potential health risks associated with low level radiation exposure from tritium. The regulatory, economic, and social implications of the new proposed limit were also considered.The new recommendation assumed a linear-no-threshold model to calculate carcinogenic risk associated with tritium exposure, and considered tritium as a non-threshold chemical carcinogen. Both of these assumptions are highly controversial given that recent research suggests that low dose exposures have thresholds below which there are no observable detrimental effects. Furthermore, mutagenic and carcinogenic risk calculated from

  4. An overview on tritium permeation barrier development for WCLL blanket concept

    NASA Astrophysics Data System (ADS)

    Aiello, A.; Ciampichetti, A.; Benamati, G.

    2004-08-01

    The reduction of tritium permeation through blanket structural materials and cooling tubes has to be carefully evaluated to minimise radiological hazards. A strong effort has been made in the past to select the best technological solution for the realisation of tritium permeation barriers (TPB) on complex structures not directly accessible after the completion of the manufacturing process. The best solution was identified in aluminium rich coatings, which form Al 2O 3 at their surface. Two technologies were selected as reference for the realisation of coating in the WCLL blanket concept: the chemical vapour deposition (CVD) process developed on laboratory scale by CEA, and the hot dipping (HD) process developed by FZK. The results obtained during three years of tests on CVD and HD coated specimens in gas and liquid metal phase are summarised and discussed.

  5. Detergent-mediated incorporation of transmembrane proteins in giant unilamellar vesicles with controlled physiological contents

    PubMed Central

    Dezi, Manuela; Di Cicco, Aurelie; Bassereau, Patricia; Lévy, Daniel

    2013-01-01

    Giant unilamellar vesicles (GUVs) are convenient biomimetic systems of the same size as cells that are increasingly used to quantitatively address biophysical and biochemical processes related to cell functions. However, current approaches to incorporate transmembrane proteins in the membrane of GUVs are limited by the amphiphilic nature or proteins. Here, we report a method to incorporate transmembrane proteins in GUVs, based on concepts developed for detergent-mediated reconstitution in large unilamellar vesicles. Reconstitution is performed either by direct incorporation from proteins purified in detergent micelles or by fusion of purified native vesicles or proteoliposomes in preformed GUVs. Lipid compositions of the membrane and the ionic, protein, or DNA compositions in the internal and external volumes of GUVs can be controlled. Using confocal microscopy and functional assays, we show that proteins are unidirectionally incorporated in the GUVs and keep their functionality. We have successfully tested our method with three types of transmembrane proteins. GUVs containing bacteriorhodopsin, a photoactivable proton pump, can generate large transmembrane pH and potential gradients that are light-switchable and stable for hours. GUVs with FhuA, a bacterial porin, were used to follow the DNA injection by T5 phage upon binding to its transmembrane receptor. GUVs incorporating BmrC/BmrD, a bacterial heterodimeric ATP-binding cassette efflux transporter, were used to demonstrate the protein-dependent translocation of drugs and their interactions with encapsulated DNA. Our method should thus apply to a wide variety of membrane or peripheral proteins for producing more complex biomimetic GUVs. PMID:23589883

  6. Centrioles regulate centrosome size by controlling the rate of Cnn incorporation into the PCM.

    PubMed

    Conduit, Paul T; Brunk, Kathrin; Dobbelaere, Jeroen; Dix, Carly I; Lucas, Eliana P; Raff, Jordan W

    2010-12-21

    centrosomes are major microtubule organizing centers in animal cells, and they comprise a pair of centrioles surrounded by an amorphous pericentriolar material (PCM). Centrosome size is tightly regulated during the cell cycle, and it has recently been shown that the two centrosomes in certain stem cells are often asymmetric in size. There is compelling evidence that centrioles influence centrosome size, but how centrosome size is set remains mysterious. we show that the conserved Drosophila PCM protein Cnn exhibits an unusual dynamic behavior, because Cnn molecules only incorporate into the PCM closest to the centrioles and then spread outward through the rest of the PCM. Cnn incorporation into the PCM is driven by an interaction with the conserved centriolar proteins Asl (Cep152 in humans) and DSpd-2 (Cep192 in humans). The rate of Cnn incorporation into the PCM is tightly regulated during the cell cycle, and this rate influences the amount of Cnn in the PCM, which in turn is an important determinant of overall centrosome size. Intriguingly, daughter centrioles in syncytial embryos only start to incorporate Cnn as they disengage from their mothers; this generates a centrosome size asymmetry, with mother centrioles always initially organizing more Cnn than their daughters. centrioles can control the amount of PCM they organize by regulating the rate of Cnn incorporation into the PCM. This mechanism can explain how centrosome size is regulated during the cell cycle and also allows mother and daughter centrioles to set centrosome size independently of one another.

  7. Marginal abatement cost curve for nitrogen oxides incorporating controls, renewable electricity, energy efficiency, and fuel switching.

    PubMed

    Loughlin, Daniel H; Macpherson, Alexander J; Kaufman, Katherine R; Keaveny, Brian N

    2017-10-01

    A marginal abatement cost curve (MACC) traces out the relationship between the quantity of pollution abated and the marginal cost of abating each additional unit. In the context of air quality management, MACCs are typically developed by sorting control technologies by their relative cost-effectiveness. Other potentially important abatement measures such as renewable electricity, energy efficiency, and fuel switching (RE/EE/FS) are often not incorporated into MACCs, as it is difficult to quantify their costs and abatement potential. In this paper, a U.S. energy system model is used to develop a MACC for nitrogen oxides (NO x ) that incorporates both traditional controls and these additional measures. The MACC is decomposed by sector, and the relative cost-effectiveness of RE/EE/FS and traditional controls are compared. RE/EE/FS are shown to have the potential to increase emission reductions beyond what is possible when applying traditional controls alone. Furthermore, a portion of RE/EE/FS appear to be cost-competitive with traditional controls. Renewable electricity, energy efficiency, and fuel switching can be cost-competitive with traditional air pollutant controls for abating air pollutant emissions. The application of renewable electricity, energy efficiency, and fuel switching is also shown to have the potential to increase emission reductions beyond what is possible when applying traditional controls alone.

  8. Genotoxic and reprotoxic effects of tritium and external gamma irradiation on aquatic animals.

    PubMed

    Adam-Guillermin, Christelle; Pereira, Sandrine; Della-Vedova, Claire; Hinton, Tom; Garnier-Laplace, Jacqueline

    2012-01-01

    Aquatic ecosystems are chronically exposed to natural radioactivity or to artificial radionuclides released by human activities (e.g., nuclear medicine and biology,nuclear industry, military applications). Should the nuclear industry expand in the future, radioactive environmental releases, under normal operating conditions or accidental ones, are expected to increase, which raises public concerns about possible consequences on the environment and human health. Radionuclide exposures may drive macromolecule alterations, and among macromolecules DNA is the major target for ionizing radiations. DNA damage, if not correctly repaired, may induce mutations, teratogenesis, and reproductive effects. As such, damage at the molecular level may have consequences at the population level. In this review, we present an overview of the literature dealing with the effects of radionuclides on DNA, development, and reproduction of aquatic organisms. The review focuses on the main radionuclides that are released by nuclear power plants under normal operating conditions, γ emitters and tritium. Additionally, we fitted nonlinear curves to the dose-response data provided in the reviewed publications and manuscripts, and thus obtained endpoints commonly associated with ecotoxicological studies, such as the EDR(10). These were then used as a common metric for comparing the values and data published in the literature.The effects of tritium on aquatic organisms were reviewed for dose rates that ranged from 29 nGy/day to 29 Gy/day. Although beta emission from tritium decay presents a rather special risk of damage to DNA, genotoxicity-induced by tritium has been scarcely studied. Most of the effects studied have related to reproduction and development. Species sensitivity and the form of tritium present are important factors that drive the ecotoxicity of tritium. We have concluded from this review that invertebrates are more sensitive to the effects of tritium than are vertebrates

  9. Tritium in well waters, streams and atomic lakes in the East Kazakhstan Oblast of the Semipalatinsk Nuclear Test Site.

    PubMed

    Mitchell, Peter I; Vintró, Luis León; Omarova, Aigul; Burkitbayev, Mukhambetkali; Nápoles, Humberto Jiménez; Priest, Nicholas D

    2005-06-01

    The concentration of tritium has been determined in well waters, streams and atomic lakes in the Sarzhal, Tel'kem, Balapan and Degelen Mountains areas of the Semipalatinsk Test Site. The data show that levels of tritium in domestic well waters within the settlement of Sarzhal are extremely low at the present time with a median value of 4.4 Bq dm(-3) (95% confidence interval:4.1-4.7 Bq dm(-3)). These levels are only marginally above the background tritium content in surface waters globally. Levels in the atomic craters at Tel'kem 1 and Tel'kem 2 are between one and two orders of magnitude higher, while the level in Lake Balapan is approximately 12,600 Bq dm(-3). Significantly, levels in streams and test-tunnel waters sourced in the Degelen Mountains, the site of approximately 215 underground nuclear tests, are a further order of magnitude higher, being in the range 133,000--235,500 Bq dm(-3). No evidence was adduced which indicates that domestic wells in Sarzhal are contaminated by tritium-rich waters sourced in the Degelen massif, suggesting that the latter are not connected hydrologically to the near-surface groundwater recharging the Sarzhal wells. Annual doses to humans arising from the ingestion of tritium in these well waters are very low at the present time and are of no radiological significance.

  10. Mg and Sr Incorporation in Foraminifer Shells: Patterns, Controls and Applications.

    NASA Astrophysics Data System (ADS)

    Lea, D. W.

    2001-12-01

    The incorporation of Mg and Sr in planktonic and benthic foraminifer shells is important for paleoceanographic research because of the potential to record physical and chemical changes in the oceanic environment. Pelagic shells are 99%+ CaCO3, and abundances of Mg and Sr are typically ~0.1%, requiring sensitive quantification methods such as ICP-MS or AES. Mg/Ca values range from 0.5 mmol/mol in cold planktics and benthics to ~5 mmol/mol in tropical planktics, with some species (Orbulina universa) having even higher values. The main control on Mg incorporation is temperature, but pH and salinity also exert small influences, presumably through calcification rate. The Mg/Ca content of the primary ontogenetic calcite can be altered by the addition of so-called gametogenic calcite, generally deposited in deep, colder waters. After deposition on the seafloor, dissolution becomes the main influence, with progressively lower Mg/Ca values in more dissolved samples. This loss appears to occur by preferential loss of the more Mg-rich portions of the shell, although the details remain unexplained. Sr/Ca values range from 0.9 in some benthic species (Uvigerina spp.) to 1.6 mmol/mol in some planktics. Culturing results suggest that temperature, salinity and pH all exert a weak control (i.e., 1% per ° C) on shell Sr, presumably through a kinetic effect. The main control appears to be related to environmental differences. For example, comparison of Sr/Ca in Neogloboquadrina pachyderma from plankton tows and cultures with core-top specimens indicates that the latter have significantly higher values, presumably due to deep crusting, perhaps added with a much higher calcification rate. This observation clearly demonstrates that Sr/Ca is not simply related to a single physical parameter such as temperature. Downcore records of shell Mg/Ca and Sr/Ca reveal substantial variability that can be correlated with known paleoceanographic change. For Mg/Ca, observed variations can largely be

  11. How to make Raman-inactive helium visible in Raman spectra of tritium-helium gas mixtures

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

    Schloesser, M.; Pakari, O.; Rupp, S.

    2015-03-15

    Raman spectroscopy, a powerful method for the quantitative compositional analysis of molecular gases, e.g. mixtures of hydrogen isotopologues, is not able to detect monoatomic species like helium. This deficit can be overcome by using radioluminescence emission from helium atoms induced by β-electrons from tritium decay. We present theoretical considerations and combined Raman/radioluminescence spectra. Furthermore, we discuss the linearity of the method together with validation measurements for determining the pressure dependence. Finally, we conclude how this technique can be used for samples of helium with traces of tritium, and vice versa. (authors)

  12. On-line tritium production monitor

    DOEpatents

    Mihalczo, John T.

    1993-01-01

    A scintillation optical fiber system for the on-line monitoring of nuclear reactions in an event-by-event manner is described. In the measurement of tritium production one or more optical fibers are coated with enriched .sup.6 Li and connected to standard scintillation counter circuitry. A neutron generated .sup.6 Li(n )T reaction occurs in the coated surface of .sup.6 Li-coated fiber to produce energetic alpha and triton particles one of which enters the optical fiber and scintillates light through the fiber to the counting circuit. The coated optical fibers can be provided with position sensitivity by placing a mirror at the free end of the fibers or by using pulse counting circuits at both ends of the fibers.

  13. On-line tritium production monitor

    DOEpatents

    Mihalczo, J.T.

    1993-11-23

    A scintillation optical fiber system for the on-line monitoring of nuclear reactions in an event-by-event manner is described. In the measurement of tritium production one or more optical fibers are coated with enriched {sup 6}Li and connected to standard scintillation counter circuitry. A neutron generated {sup 6}Li(n)T reaction occurs in the coated surface of {sup 6}Li-coated fiber to produce energetic alpha and triton particles one of which enters the optical fiber and scintillates light through the fiber to the counting circuit. The coated optical fibers can be provided with position sensitivity by placing a mirror at the free end of the fibers or by using pulse counting circuits at both ends of the fibers. 5 figures.

  14. Tritium, deuterium, and oxygen-18 in water collected from unsaturated sediments near a low-level radioactive-waste burial site south of Beatty, Nevada

    USGS Publications Warehouse

    Prudic, David E.; Stonestrom, David A.; Striegl, Robert G.

    1997-01-01

    Pore water was extracted in March 1996 from cores collected from test holes UZB-1 and UZB-2 drilled November 1992 and September 1993, respectively, in the Amargosa Desert south of Beatty, Nevada. The test holes are part of a study to determine factors affecting water and gas movement through unsaturated sediments. The holes are about 100 meters south of the southwest corner of the fence enclosing a commercial burial area for low-level radioactive waste. Water vapor collected from test hole UZB-2 in April 1994 and July 1995 had tritium concentrations greater than would be expected from atmospheric deposition. An apparatus was built in which pore water was extracted by cryodistillation from the previously obtained core samples. The extracted core water was analyzed for the radioactive isotope tritium and for the stable isotopes deuterium (D) and oxygen-18 (18O). The isotopic composition of core water was compared with that of water vapor previously collected from air ports in test hole UZB-2 and to additional samples collected during May 1996. Core water becomes increasingly depleted in D and 18O from the land surface to a depth of 30 meters, indicating that net evaporation of water is occurring near the land surface. Below a depth of 30 meters the stable-isotopic composition of core water becomes nearly constant and roughly equal to that of ground water. The stable isotopes plot on an evaporation trend. The source of the partly evaporated water could be either ground water or past precipitation having the same average isotopic composition as ground water but not modern precipitation, based on 18 months of record. Profiles of D and 18O in water vapor roughly parallel those in core water. The stable isotopes of core water appear to be in isotopic equilibrium with water vapor from UZB-2 when temperature-dependent fractionation is considered. The data are consistent with the hypothesis of evaporative discharge of ground water at the land surface. The concentration of

  15. Human Health and the Biological Effects of Tritium in Drinking Water: Prudent Policy Through Science – Addressing the ODWAC New Recommendation

    PubMed Central

    Dingwall, S.; Mills, C.E.; Phan, N.; Taylor, K.; Boreham, D.R.

    2011-01-01

    Tritium is a radioactive form of hydrogen and is a by-product of energy production in Canadian Deuterium Uranium (CANDU) reactors. The release of this radioisotope into the environment is carefully managed at CANDU facilities in order to minimize radiation exposure to the public. However, under some circumstances, small accidental releases to the environment can occur. The radiation doses to humans and non-human biota from these releases are low and orders of magnitude less than doses received from naturally occurring radioisotopes or from manmade activities, such as medical imaging and air travel. There is however a renewed interest in the biological consequences of low dose tritium exposures and a new limit for tritium levels in Ontario drinking water has been proposed. The Ontario Drinking Water Advisory Council (ODWAC) issued a formal report in May 2009 in response to a request by the Minister of the Environment, concluding that the Ontario Drinking Water Quality Standard for tritium should be revised from the current 7,000 Bq/L level to a new, lower 20 Bq/L level. In response to this recommendation, an international scientific symposium was held at McMaster University to address the issues surrounding this change in direction and the validity of a new policy. Scientists, regulators, government officials, and industrial stakeholders were present to discuss the potential health risks associated with low level radiation exposure from tritium. The regulatory, economic, and social implications of the new proposed limit were also considered. The new recommendation assumed a linear-no-threshold model to calculate carcinogenic risk associated with tritium exposure, and considered tritium as a non-threshold chemical carcinogen. Both of these assumptions are highly controversial given that recent research suggests that low dose exposures have thresholds below which there are no observable detrimental effects. Furthermore, mutagenic and carcinogenic risk calculated from

  16. Measurement of tritium in the free water of milk : spotting and quantifying some biases and proposing ways of improvement.

    PubMed

    Le Goff, Pierre; Duda, Jean-Marie; Guétat, Philippe; Rambaud, Pauline; Mavon, Christophe; Vichot, Laurent; Badot, Pierre-Marie; Fromm, Michel

    2014-01-01

    As one of the three natural isotopes of hydrogen, tritium is ubiquitous and may potentially be present in any water or organic molecule that constitutes a biological matrix. Milk is one of the most frequently monitored foodstuffs in the vicinity of chronic release of radionuclides, as it is a very common food product and also because it integrates deposition on large areas of grass or crops at a local scale. Different parameters have been studied to assess their impact on the reliability of tritium measurements in the free water of milk. The volume of the sample, the technique used to extract the water and the level of dehydration modulate the results but in different ways: dispersion of results and under- or over-estimation of the tritium activity. The influence of sample storage and preparation has also been investigated. Methodological improvements of tritium measurements in the free water of milk are proposed. An original fractionation effect during distillation of milk is also described. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Behavior of tritium permeation induced by water corrosion of alpha iron around room temperature

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

    Otsuka, T.; Hashizume, K.

    2015-03-15

    Tritium (T) permeation leakage to surroundings is a great safety concern in fission and fusion reactor systems. T permeation potentially occurs from T contaminated water through cooling tubes or storage tank made of metals which dissolve some T evolved by water corrosion. In order to understand behaviors of hydrogen uptake and permeation in pure α-iron (αFe) during water corrosion around room temperature, hydrogen permeation experiments for an αFe membrane have been conducted by means of tritium tracer techniques. The present study suggests that hydrogen produced by water corrosion of αFe is trapped in product oxide layers to delay hydrogen uptakemore » in αFe for a moment. However, the oxide layers do not work as a sufficient barrier for hydrogen uptake. Some of hydrogen dissolved in αFe normally diffuses and permeates through the bulk in the early stage of permeation. In a later stage, hydrogen permeation could be apparently stopped by the disappearance of concentration difference of tritium. Hydrogen partial pressure at the water/αFe interface could be ranged from 0.7 to 9.5 kPa around room temperature.« less

  18. RESULTS OF TRITIUM TRACKING AND GROUNDWATER MONITORING AT THE HANFORD SITE 200 AREA STATE APPROVED LAND DISPOSAL SITE FY2008

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

    ERB DB

    2008-11-19

    The Hanford Site's 200 Area Effluent Treatment Facility (ETF) processes contaminated aqueous wastes derived from Hanford Site facilities. The treated wastewater occasionally contains tritium, which cannot be removed by the ETF prior to the wastewater being discharged to the 200 Area State-Approved Land Disposal Site (SALDS). During the first 11 months of fiscal year 2008 (FY08) (September 1, 2007, to July 31, 2008), approximately 75.15 million L (19.85 million gal) of water were discharged to the SALDS. Groundwater monitoring for tritium and other constituents, as well as water-level measurements, is required for the SALDS by State Waste Discharge Permit Numbermore » ST-4500 (Ecology 2000). The current monitoring network consists of three proximal (compliance) monitoring wells and nine tritium-tracking wells. Quarterly sampling of the proximal wells occurred in October 2007 and in January/February 2008, April 2008, and August 2008. The nine tritium-tracking wells, including groundwater monitoring wells located upgradient and downgradient of the SALDS, were sampled in January through April 2008. Water-level measurements taken in the three proximal SALDS wells indicate that a small groundwater mound is present beneath the facility, which is a result of operational discharges. The mound increased in FY08 due to increased ETF discharges from treating groundwater from extraction wells at the 200-UP-l Operable Unit and the 241-T Tank Farm. Maximum tritium activities increased by an order of magnitude at well 699-48-77A (to 820,000 pCi/L in April 2008) but remained unchanged in the other two proximal wells. The increase was due to higher quantities of tritium in wastewaters that were treated and discharged in FY07 beginning to appear at the proximal wells. The FY08 tritium activities for the other two proximal wells were 68,000 pCi/L at well 699-48-77C (October 2007) and 120,000 pCi/L at well 699-48-77D (October 2007). To date, no indications of a tritium incursion from

  19. Incorporating swirl effects into the coefficient of momentum for separation control

    NASA Astrophysics Data System (ADS)

    Taira, Kunihiko; Munday, Phillip

    2017-11-01

    Addition of swirl in flow control has been known to enhance suppression of separation over airfoils at high angles of attack. Utilizing large eddy simulations, the present open-loop control study examines the influence of wall-normal and angular momentum injections in mitigating separation over a NACA0012 airfoil at α =9° and Re = 23 , 000 . We introduce these swirling jets near the separation point with wall-normal momentum and swirl independently prescribed through velocity boundary conditions. The changes to the flow from control are examined and the corresponding lift enhancement and drag reduction are assessed as a function of the two velocity components. Since the standard coefficient of momentum does not consider swirling effects, we extend its definition to incorporate both the wall-normal momentum and swirl to quantify the overall flow control effectiveness. We are able to observe a trend in lift force enhancement over this single modified coefficient of momentum (that is dependent on the non-dimensional jet velocity ratio and swirl number). Moreover, we are able to identify a critical value for the modified momentum coefficient and categorize controlled flows into separated, transitional, and attached flows. This work was supported by the Air Force Office of Scientific Research (Award Number FA9550-13-1-0183) and the Office of Naval Research (Award Number N00014-16-1-2443).

  20. RAMI modeling of plant systems for proposed tritium production and extraction facilities

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

    Blanchard, A.

    2000-04-05

    The control of life-cycle cost is a primary concern during the development, construction, operation, and decommissioning of DOE systems and facilities. An effective tool that can be used to control these costs, beginning with the design stage, is called a reliability, availability, maintainability, and inspectability analysis or, simply, RAMI for short. In 1997, RAMI technology was introduced to the Savannah River Site with applications at the conceptual design stage beginning with the Accelerator Production of Tritium (APT) Project and later extended to the Commercial Light Water Reactor (CLWR) Tritium Extraction Facility (TEF) Project. More recently it has been applied tomore » the as-build Water Treatment Facilities designed for ground water environmental restoration. This new technology and database was applied to the assessment of balance-of-plant systems for the APT Conceptual Design Report. Initial results from the Heat Removal System Assessment revealed that the system conceptual design would cause the APT to fall short of its annual production goal. Using RAM technology to immediately assess this situation, it was demonstrated that the product loss could be gained back by upgrading the system's chiller unit capacity at a cost of less than $1.3 million. The reclaimed production is worth approximately $100 million. The RAM technology has now been extended to assess the conceptual design for the CLWR-TEF Project. More specifically, this technology and database is being used to translate high level availability goals into lower level system design requirements that will ensure the TEF meets its production goal. Results, from the limited number of system assessments performed to date, have already been used to modify the conceptual design for a remote handling system, improving its availability to the point that a redundant system, with its associated costs of installation and operation may no longer be required. RAMI results were also used to justify the

  1. Addressing the need for an infection prevention and control framework that incorporates the role of surveillance: a discussion paper.

    PubMed

    Mitchell, Brett G; Gardner, Anne

    2014-03-01

    To present a discussion on theoretical frameworks in infection prevention and control. Infection prevention and control programmes have been in place for several years in response to the incidence of healthcare-associated infections and their associated morbidity and mortality. Theoretical frameworks play an important role in formalizing the understanding of infection prevention activities. Discussion paper. A literature search using electronic databases was conducted for published articles in English addressing theoretical frameworks in infection prevention and control between 1980-2012. Nineteen papers that included a reference to frameworks were identified in the review. A narrative analysis of these papers was completed. Two models were identified and neither included the role of surveillance. To reduce the risk of acquiring a healthcare-associated infection, a multifaceted approach to infection prevention is required. One key component in this approach is surveillance. The review identified two infection prevention and control frameworks, yet these are rarely applied in infection prevention and control programmes. Only one framework considered the multifaceted approach required for infection prevention. It did not, however, incorporate the role of surveillance. We present a framework that incorporates the role of surveillance into a biopsychosocial approach to infection prevention and control. Infection prevention and control programmes and associated research are led primarily by nurses. There is a need for an explicit infection prevention and control framework incorporating the important role that surveillance has in infection prevention activities. This study presents one framework for further critique and discussion. © 2013 John Wiley & Sons Ltd.

  2. Development of tritium permeation barriers on Al base in Europe

    NASA Astrophysics Data System (ADS)

    Benamati, G.; Chabrol, C.; Perujo, A.; Rigal, E.; Glasbrenner, H.

    The development of the water cooled lithium lead (WCLL) DEMO fusion reactor requires the production of a material capable of acting as a tritium permeation barrier (TPB). In the DEMO blanket reactor permeation barriers on the structural material are required to reduce the tritium permeation from the Pb-17Li or the plasma into the cooling water to acceptable levels (<1 g/d). Because of experimental work previously performed, one of the most promising TPB candidates is A1 base coatings. Within the EU a large R&D programme is in progress to develop a TPB fabrication technique, compatible with the structural materials requirements and capable of producing coatings with acceptable performances. The research is focused on chemical vapour deposition (CVD), hot dipping, hot isostatic pressing (HIP) technology and spray (this one developed also for repair) deposition techniques. The final goal is to select a reference technique to be used in the blanket of the DEMO reactor and in the ITER test module fabrication. The activities performed in four European laboratories are summarised here.

  3. Tritium assay of Li/sub 2/O in the LBM/LOTUS experiments

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

    Quanci, J.; Azam, S.; Bertone, P.

    1986-11-01

    The Lithium Blanket Module (LBM) is an assembly of over 20,000 cylindrical lithium oxide pellets in an array representative of a limited-coverage breeding zone for a toroidal fusion device. A principal objective of the LBM program is to test the ability of advanced neutronics coding to model the tritium breeding characteristics of a fusion device blanket. The LBM has been irradiated at the Ecole Polytechnique Federale de Lausanne (EPFL) LOTUS facility with a 14 MeV point-neutron source. Princeton Plasma Physics Laboratory (PPPL) and EPFL assayed the tritium bred in lithium oxide diagnostic samples placed at various positions in the LBM.more » PPPL employed a thermal extraction technique while EPFL used a dissolution method. The results for the assay are reported and compared to MCNP Monte Carlo neutronics calculations for the LBM/LOTUS system.« less

  4. A compact tritium enrichment unit for large sample volumes with automated re-filling and higher enrichment factor.

    PubMed

    Kumar, B; Han, L-F; Wassenaar, L I; Klaus, P M; Kainz, G G; Hillegonds, D; Brummer, D; Ahmad, M; Belachew, D L; Araguás, L; Aggarwal, P

    2016-12-01

    Tritium ( 3 H) in natural waters is a powerful tracer of hydrological processes, but its low concentrations require electrolytic enrichment before precise measurements can be made with a liquid scintillation counter. Here, we describe a newly developed, compact tritium enrichment unit which can be used to enrich up to 2L of a water sample. This allows a high enrichment factor (>100) for measuring low 3 H contents of <0.05TU. The TEU uses a small cell (250mL) with automated re-filling and a CO 2 bubbling technique to neutralize the high alkalinity of enriched samples. The enriched residual sample is retrieved from the cell under vacuum by cryogenic distillation at -20°C and the tritium enrichment factor for each sample is accurately determined by measuring pre- and post- enrichment 2 H concentrations with laser spectrometry. Copyright © 2016. Published by Elsevier Ltd.

  5. UNCLASSIFIED TPBAR RELEASES, INCLUDING TRITIUM TTQP-1-091 Rev 14

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

    Gruel, Robert L.; Love, Edward F.; Thornhill, Cheryl K.

    This document provides a listing of unclassified tritium release values that should be assumed for unclassified analysis. Much of the information is brought forth from the related documents listed in Section 5.0 to provide a single-source listing of unclassified release values. This information has been updated based on current design analysis and available experimental data.

  6. Tritium leak triggers reactor shutdown in the US

    NASA Astrophysics Data System (ADS)

    Gwynne, Peter

    2010-04-01

    A US state has voted against renewing the operating licence for its only working nuclear reactor after a leak of tritium was found in the 38-year-old power plant. The decision in late February by Vermont's senate to close the 650 MW Vermont Yankee reactor has cast a shadow over the Obama administration's plans to encourage the construction of more nuclear power plants to meet the country's increasing electricity demands. The plant currently provides one-third of the state's electricity demands.

  7. Helium-3 blankets for tritium breeding in fusion reactors

    NASA Technical Reports Server (NTRS)

    Steiner, Don; Embrechts, Mark; Varsamis, Georgios; Vesey, Roger; Gierszewski, Paul

    1988-01-01

    It is concluded that He-3 blankets offers considerable promise for tritium breeding in fusion reactors: good breeding potential, low operational risk, and attractive safety features. The availability of He-3 resources is the key issue for this concept. There is sufficient He-3 from decay of military stockpiles to meet the International Thermonuclear Experimental Reactor needs. Extraterrestrial sources of He-3 would be required for a fusion power economy.

  8. THE EFFECTS OF HYDROGEN, TRITIUM, AND HEAT TREATMENT ON THE DEFORMATION AND FRACTURE TOUGHNESS PROPERTIES OF STAINLESS STEEL

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

    Morgan, M.; Tosten, M.; Chapman, G.

    2013-09-06

    The deformation and fracture toughness properties of forged stainless steels pre-charged with tritium were compared to the deformation and fracture toughness properties of the same steels heat treated at 773 K or 873 K and precharged with hydrogen. Forged stainless steels pre-charged with tritium exhibit an aging effect: Fracture toughness values decrease with aging time after precharging because of the increase in concentration of helium from tritium decay. This study shows that forged stainless steels given a prior heat treatment and then pre-charged with hydrogen also exhibit an aging effect: Fracture toughness values decrease with increasing time at temperature. Amore » microstructural analysis showed that the fracture toughness reduction in the heat-treated steels was due to patches of recrystallized grains that form within the forged matrix during the heat treatment. The combination of hydrogen and the patches of recrystallized grains resulted in more deformation twinning. Heavy deformation twinning on multiple slip planes was typical for the hydrogen-charged samples; whereas, in the non-charged samples, less twinning was observed and was generally limited to one slip plane. Similar effects occur in tritium pre-charged steels, but the deformation twinning is brought on by the hardening associated with decay helium bubbles in the microstructure.« less

  9. HEAT TRANSFER AND TRITIUM PRODUCING SYSTEM

    DOEpatents

    Johnson, E.F.

    1962-06-01

    This invention related to a circulating lithium-containing blanket system in a neution source hav'ing a magnetic field associated therewith. The blanket serves simultaneously and efficiently as a heat transfer mediunm and as a source of tritium. The blanket is composed of a lithium-6-enriched fused salt selected from the group consisting of lithium nitrite, lithium nitrate, a mixture of said salts, a mixture of each of said salts with lithium oxide, and a mixture of said salts with each other and with lithium oxide. The moderator, which is contained within the blanket in a separate conduit, can be water. A stellarator is one of the neutron sources which can be used in this invention. (AEC)

  10. Optimization of low-level LS counter Quantulus 1220 for tritium determination in water samples

    NASA Astrophysics Data System (ADS)

    Jakonić, Ivana; Todorović, Natasa; Nikolov, Jovana; Bronić, Ines Krajcar; Tenjović, Branislava; Vesković, Miroslav

    2014-05-01

    Liquid scintillation counting (LSC) is the most commonly used technique for measuring tritium. To optimize tritium analysis in waters by ultra-low background liquid scintillation spectrometer Quantulus 1220 the optimization of sample/scintillant ratio, choice of appropriate scintillation cocktail and comparison of their efficiency, background and minimal detectable activity (MDA), the effect of chemi- and photoluminescence and combination of scintillant/vial were performed. ASTM D4107-08 (2006) method had been successfully applied in our laboratory for two years. During our last preparation of samples a serious quench effect in count rates of samples that could be consequence of possible contamination by DMSO was noticed. The goal of this paper is to demonstrate development of new direct method in our laboratory proposed by Pujol and Sanchez-Cabeza (1999), which turned out to be faster and simpler than ASTM method while we are dealing with problem of neutralization of DMSO in apparatus. The minimum detectable activity achieved was 2.0 Bq l-1 for a total counting time of 300 min. In order to test the optimization of system for this method tritium level was determined in Danube river samples and also for several samples within intercomparison with Ruđer Bošković Institute (IRB).

  11. In situ measurements of tritium evapotranspiration (³H-ET) flux over grass and soil using the gradient and eddy covariance experimental methods and the FAO-56 model.

    PubMed

    Connan, O; Maro, D; Hébert, D; Solier, L; Caldeira Ideas, P; Laguionie, P; St-Amant, N

    2015-10-01

    The behaviour of tritium in the environment is linked to the water cycle. We compare three methods of calculating the tritium evapotranspiration flux from grassland cover. The gradient and eddy covariance methods, together with a method based on the theoretical Penmann-Monteith model were tested in a study carried out in 2013 in an environment characterised by high levels of tritium activity. The results show that each of the three methods gave similar results. The various constraints applying to each method are discussed. The results show a tritium evapotranspiration flux of around 15 mBq m(-2) s(-1) in this environment. These results will be used to improve the entry parameters for the general models of tritium transfers in the environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Tritium autoradiography with thinned and back-side illuminated monolithic active pixel sensor device

    NASA Astrophysics Data System (ADS)

    Deptuch, G.

    2005-05-01

    The first autoradiographic results of the tritium ( 3H) marked source obtained with monolithic active pixel sensors are presented. The detector is a high-resolution, back-side illuminated imager, developed within the SUCIMA collaboration for low-energy (<30 keV) electrons detection. The sensitivity to these energies is obtained by thinning the detector, originally fabricated in the form of a standard VLSI chip, down to the thickness of the epitaxial layer. The detector used is the 1×10 6 pixel, thinned MIMOSA V chip. The low noise performance and thin (˜160 nm) entrance window provide the sensitivity of the device to energies as low as ˜4 keV. A polymer tritium source was parked directly atop the detector in open-air conditions. A real-time image of the source was obtained.

  13. Tritium labeling of a powerful methylphosphonate inhibitor of cholinesterase: synthesis and biological applications

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

    Balan, A.; Barness, I.; Simon, G.

    1988-02-15

    7-(Methylethoxy phosphinyloxy)-1-methyl-quinolinium iodide (MEPQ), a powerful anti-cholinesterase methylphosphonate ester, was labeled with tritium (9 Ci/mmol) at the methylphosphonyl moiety (TCH2P(O)(OR)X) by an iodine-tritium replacement reaction. Kinetic measurements of the rate of inhibition of acetylcholinesterase (AChE) by (/sup 3/H)MEPQ and its rate of hydrolysis in alkaline solution confirmed the identity of (/sup 3/H)MEPQ with authentic MEPQ, which was prepared by the same reaction sequences. Gel-filtration experiments verified the radiospecificity of (/sup 3/H)MEPQ. In vitro radiolabeling of both AChE and butyrylcholinesterase along with the whole-body autoradiography of (/sup 3/H)MEPQ-treated mice suggests that (/sup 3/H)MEPQ is a convenient marker for studying biological systemsmore » containing these esterases.« less

  14. Deuterium-tritium experiments on the Tokamak Fusion Test reactor

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

    Hosea, J.; Adler, J.H.; Alling, P.

    The deuterium-tritium (D-T) experimental program on the Tokamak Fusion Test Reactor (TFTR) is underway and routine tritium operations have been established. The technology upgrades made to the TFTR facility have been demonstrated to be sufficient for supporting both operations and maintenance for an extended D-T campaign. To date fusion power has been increased to {approx}9 MW and several physics results of importance to the D-T reactor regime have been obtained: electron temperature, ion temperature, and plasma stored energy all increase substantially in the D-T regime relative to the D-D regime at the same neutral beam power and comparable limiter conditioning;more » possible alpha electron heating is indicated and energy confinement improvement with average ion mass is observed; and alpha particle losses appear to be classical with no evidence of TAE mode activity up to the PFUS {approx}6 MW level. Instability in the TAE mode frequency range has been observed at PFUS > 7 MW and its effect on performance in under investigation. Preparations are underway to enhance the alpha particle density further by increasing fusion power and by extending the neutral beam pulse length to permit alpha particle effects of relevance to the ITER regime to be more fully explored.« less

  15. Modification of a method-of-characteristics solute-transport model to incorporate decay and equilibrium-controlled sorption or ion exchange

    USGS Publications Warehouse

    Goode, D.J.; Konikow, Leonard F.

    1989-01-01

    The U.S. Geological Survey computer model of two-dimensional solute transport and dispersion in ground water (Konikow and Bredehoeft, 1978) has been modified to incorporate the following types of chemical reactions: (1) first-order irreversible rate-reaction, such as radioactive decay; (2) reversible equilibrium-controlled sorption with linear, Freundlich, or Langmuir isotherms; and (3) reversible equilibrium-controlled ion exchange for monovalent or divalent ions. Numerical procedures are developed to incorporate these processes in the general solution scheme that uses method-of- characteristics with particle tracking for advection and finite-difference methods for dispersion. The first type of reaction is accounted for by an exponential decay term applied directly to the particle concentration. The second and third types of reactions are incorporated through a retardation factor, which is a function of concentration for nonlinear cases. The model is evaluated and verified by comparison with analytical solutions for linear sorption and decay, and by comparison with other numerical solutions for nonlinear sorption and ion exchange.

  16. Synergistic effects of surface erosion on tritium inventory and permeation in metallic plasma facing armours

    NASA Astrophysics Data System (ADS)

    Federici, G.; Holland, D. F.; Matera, R.

    1996-10-01

    In the next generation of DT fuelled tokamaks, i.e., the International Thermonuclear Experimental Reactor (ITER) implantation of energetic DT particles on some portions of the plasma facing components (PFCs) will take place along with significant erosion of the armour surfaces. As a result of the simultaneous removal of material from the front surface, the build-up of tritium inventory and the start of permeation originating in the presence of large densities of neutron-induced traps is expected to be influenced considerably and special provisions could be required to minimise the consequences on the design. This paper reports on the results of a tritium transport modelling study based on a new model which describes the migration of implanted tritium across the bulk of metallic plasma facing materials containing neutron-induced traps which can capture it and includes the synergistic effects of surface erosion. The physical basis of the model is summarised, but emphasis is on the discussion of the results of a comparative study performed for beryllium and tungsten armours for ranges of design and operation conditions similar to those anticipated in the divertor of ITER.

  17. Testing Lorentz invariance violations in the tritium beta-decay anomaly

    NASA Astrophysics Data System (ADS)

    Carmona, J. M.; Cortés, J. L.

    2000-11-01

    We consider a Lorentz non-invariant dispersion relation for the neutrino, which would produce unexpected effects with neutrinos of few eV, exactly where the tritium beta-decay anomaly is found. We use this anomaly to put bounds on the violation of Lorentz invariance. We discuss other consequences of this non-invariant dispersion relation in neutrino experiments and high-energy cosmic-ray physics.

  18. Water and tritium movement through the unsaturated zone at a low-level radioactive-waste disposal site near Sheffield, Illinois, 1981-85

    USGS Publications Warehouse

    Mills, Patrick C.; Healy, R.W.

    1991-01-01

    The movement of water and tritium through the unsaturated zone was studied at a low-level radioactive-waste disposal site near Sheffield, Bureau County, Illinois, from 1981 to 1985. Water and tritium movement occurred in an annual, seasonally timed cycle; recharge to the saturated zone generally occurred in the spring and early summer. Mean annual precipitation (1982-85) was 871 millimeters; mean annual recharge to the disposal trenches (July 1982 through June 1984) was estimated to be 107 millimeters. Average annual tritium flux below the study trenches was estimated to be 3.4 millicuries per year. Site geology, climate, and waste-disposal practices influenced the spatial and temporal variability of water and tritium movement. Of the components of the water budget, evapotranspiration contributed most to the temporal variability of water and tritium movement. Disposal trenches are constructed in complexly layered glacial and postglacial deposits that average 17 meters in thickness and overlie a thick sequence of Pennsylvanian shale. The horizontal saturated hydraulic conductivity of the clayey-silt to sand-sized glacial and postglacial deposits ranges from 4.8x10^-1 to 3.4x10^4 millimeters per day. A 120-meter-long horizontal tunnel provided access for hydrologic measurements and collection of sediment and water samples from the unsaturated and saturated geologic deposits below four disposal trenches. Trench-cover and subtrench deposits were monitored with soil-moisture tensiometers, vacuum and gravity lysimeters, piezometers, and a nuclear soil-moisture gage. A cross-sectional, numerical ground-water-flow model was used to simulate water movement in the variably saturated geologic deposits in the tunnel area. Concurrent studies at the site provided water-budget data for estimating recharge to the disposal trenches. Vertical water movement directly above the trenches was impeded by a zone of compaction within the clayey-silt trench covers. Water entered the

  19. First results of a simultaneous measurement of tritium and 14C in an ultra-low-background proportional counter for environmental sources of methane

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

    Mace, Emily K.; Aalseth, Craig E.; Day, Anthony R.

    Abstract Simultaneous measurement of tritium and 14C would provide an added tool for tracing organic compounds through environmental systems and is possible via beta energy spectroscopy of sample-derived methane in internal-source gas proportional counters. Since the mid-1960’s atmospheric tritium and 14C have fallen dramatically as the isotopic injections from above-ground nuclear testing have been diluted into the ocean and biosphere. In this work, the feasibility of simultaneous tritium and 14C measurements via proportional counters is revisited in light of significant changes in both the atmospheric and biosphere isotopics and the development of new ultra-low-background gas proportional counting capabilities for smallmore » samples (roughly 50 cc methane). A Geant4 Monte Carlo model of a Pacific Northwest National Laboratory (PNNL) proportional counter response to tritium and 14C is used to analyze small samples of two different methane sources to illustrate the range of applicability of contemporary simultaneous measurements and their limitations. Because the two methane sources examined were not sample size limited, we could compare the small-sample measurements performed at PNNL with analysis of larger samples performed at a commercial laboratory. The dual-isotope simultaneous measurement is well matched for methane samples that are atmospheric or have an elevated source of tritium (i.e. landfill gas). For samples with low/modern tritium isotopics (rainwater), commercial separation and counting is a better fit.« less

  20. Spinal motor control system incorporates an internal model of limb dynamics.

    PubMed

    Shimansky, Y P

    2000-10-01

    The existence and utilization of an internal representation of the controlled object is one of the most important features of the functioning of neural motor control systems. This study demonstrates that this property already exists at the level of the spinal motor control system (SMCS), which is capable of generating motor patterns for reflex rhythmic movements, such as locomotion and scratching, without the aid of the peripheral afferent feedback, but substantially modifies the generated activity in response to peripheral afferent stimuli. The SMCS is presented as an optimal control system whose optimality requires that it incorporate an internal model (IM) of the controlled object's dynamics. A novel functional mechanism for the integration of peripheral sensory signals with the corresponding predictive output from the IM, the summation of information precision (SIP) is proposed. In contrast to other models in which the correction of the internal representation of the controlled object's state is based on the calculation of a mismatch between the internal and external information sources, the SIP mechanism merges the information from these sources in order to optimize the precision of the controlled object's state estimate. It is demonstrated, based on scratching in decerebrate cats as an example of the spinal control of goal-directed movements, that the results of computer modeling agree with the experimental observations related to the SMCS's reactions to phasic and tonic peripheral afferent stimuli. It is also shown that the functional requirements imposed by the mathematical model of the SMCS comply with the current knowledge about the related properties of spinal neuronal circuitry. The crucial role of the spinal presynaptic inhibition mechanism in the neuronal implementation of SIP is elucidated. Important differences between the IM and a state predictor employed for compensating for a neural reflex time delay are discussed.

  1. RAMI modeling of selected balance of plant systems for the proposed Accelerator Production of Tritium (APT) project

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

    Radder, J.A.; Cramer, D.S.

    1997-06-01

    In order to meet Department of Energy (DOE) Defense Program requirements for tritium in the 2005-2007 time frame, new production capability must be made available. The Accelerator Production of Tritium (APT) Plant is being considered as an alternative to nuclear reactor production of tritium, which has been the preferred method in the past. The proposed APT plant will use a high-power proton accelerator to generate thermal neutrons that will be captured in {sup 3}He to produce tritium (3H). It is expected that the APT Plant will be built and operated at the DOE`s Savannah River Site (SRS) in Aiken, Southmore » Carolina. Discussion is focused on Reliability, Availability, Maintainability, and Inspectability (RAMI) modeling of recent conceptual designs for balance of plant (BOP) systems in the proposed APT Plant. In the conceptual designs for balance of plant (BOP) systems in the proposed APT Plant. In the conceptual design phase, system RAMI estimates are necessary to identify the best possible system alternative and to provide a valid picture of the cost effectiveness of the proposed system for comparison with other system alternatives. RAMI estimates in the phase must necessarily be based on generic data. The objective of the RAMI analyses at the conceptual design stage is to assist the designers in achieving an optimum design which balances the reliability and maintainability requirements among the subsystems and components.« less

  2. On Optimizing H. 264/AVC Rate Control by Improving R-D Model and Incorporating HVS Characteristics

    NASA Astrophysics Data System (ADS)

    Zhu, Zhongjie; Wang, Yuer; Bai, Yongqiang; Jiang, Gangyi

    2010-12-01

    The state-of-the-art JVT-G012 rate control algorithm of H.264 is improved from two aspects. First, the quadratic rate-distortion (R-D) model is modified based on both empirical observations and theoretical analysis. Second, based on the existing physiological and psychological research findings of human vision, the rate control algorithm is optimized by incorporating the main characteristics of the human visual system (HVS) such as contrast sensitivity, multichannel theory, and masking effect. Experiments are conducted, and experimental results show that the improved algorithm can simultaneously enhance the overall subjective visual quality and improve the rate control precision effectively.

  3. Towards high-precision measurement of the Tritium - He-3 mass difference

    NASA Astrophysics Data System (ADS)

    Shi, Wei; Redshaw, Matthew; Victoria, Juliette; Myers, Edmund

    2004-05-01

    An independent measurement of the mass difference of ^3He-^3T provides an important check of systematic errors in tritium beta-decay experiments that set limits to the electron anti-neutrino mass [1]. Using the precision Penning trap system developed at MIT but recently relocated to Florida State University [2], and the simultaneous two-ion cyclotron frequency measurement technique recently developed at MIT [3], we aim to measure this mass difference to better than 30 meV/c^2, more than an order of magnitude improvement over previous measurements [4,5]. Problems being addressed include producing single T^+ ions in the trap without spoiling the vacuum with ^3He, and the extension of the MIT techniques to ions of lighter mass. [1] KATRIN: http://iklau1.fzk.de/tritium [2] See abstract by Redshaw et al. [3] S. Rainville, J.K. Thompson, and D.E. Pritchard, Science 303, 334 (2004). [4] R.S. Van Dyck, D.L. Farnham, and P.B. Schwinberg, PRL 70, 2888 (1993). [5] G. Audi, A.H. Wapstra, and C. Thibault, Nuclear Physics A729, 337 (2003).

  4. Monte Carlo calculation of energy deposition in ionization chambers for tritium measurements

    NASA Astrophysics Data System (ADS)

    Zhilin, Chen; Shuming, Peng; Dan, Meng; Yuehong, He; Heyi, Wang

    2014-10-01

    Energy deposition in ionization chambers for tritium measurements has been theoretically studied using Monte Carlo code MCNP 5. The influence of many factors, including carrier gas, chamber size, wall materials and gas pressure, has been evaluated in the simulations. It is found that β rays emitted by tritium deposit much more energy into chambers flowing through with argon than with deuterium in them, as much as 2.7 times higher at pressure 100 Pa. As chamber size gets smaller, energy deposition decreases sharply. For an ionization chamber of 1 mL, β rays deposit less than 1% of their energy at pressure 100 Pa and only 84% even if gas pressure is as high as 100 kPa. It also indicates that gold plated ionization chamber results in the highest deposition ratio while aluminum one leads to the lowest. In addition, simulations were validated by comparison with experimental data. Results show that simulations agree well with experimental data.

  5. Production of tritium, neutrons, and heat based on the transmission resonance model (TRM) for cold fusion

    NASA Astrophysics Data System (ADS)

    Bush, Robert T.

    1991-05-01

    The TRM has recently been successful in fitting calorimetric data having interesting nonlinear structure. The model appears to provide a natural description for electrolytic cold fusion in terms of ``fractals''. Extended to the time dimension, the model can apparently account for the phenomenon of heat ``bursts''. The TRM combines a transmission condition involving quantized energies and an engergy shift of a Maxwell-Boltzmann energy distribution of deuterons at the cathodic surface that appears related to the concentration overpotential (hydrogen overvoltage). The model suggest three possible regimes vis-a-vis tritium production in terms of this energy shift, and indicates why measurable tritium production in the electrolytic case will tend to be the exception rather than the rule in absence of a recipe: Below a shift of approximately 2.8 meV there is production of both tritium and measureable excess heat, with the possibility of accounting for the Bockris curve indicating about a 1% correlation between excess heat and tritium. However, over the large range from about 2.8 meV to 340 meV energy shift there is a regime of observable excess heat production but little, and probably no measurable, tritium production. The third regime is more hypothetical: It begins at an energy shift of about 1 keV and extends to the boundaries of ``hot'' fusion at about 10 keV. A new type of nucelar reaction, trint (for transmission resonance-induced neutron transfer), is suggested by the model leading to triton and neutron production. A charge distribution ``polarization conjecture'' is the basis for theoretical derivation for the low-energy limit for an energy-dependent branching ratio for D-on-D. When the values of the parameters are inserted, this expression yields an estimate for the ratio of neutron-to-triton production of about 1.64×10-9. The possibility of some three-body reactions is also suggested. A comparison of the TRM's transmission energy levels for palladium deuteride

  6. Materials and fabrication technology of modules intended for irradiation tests of blanket tritium-breeding zones in Russian fusion reactor projects

    NASA Astrophysics Data System (ADS)

    Kapychev, V.; Davydov, D.; Gorokhov, V.; Ioltukhovskiy, A.; Kazennov, Yu; Tebus, V.; Frolov, V.; Shikov, A.; Shishkov, N.; Kovalenko, V.; Shishkin, N.; Strebkov, Yu

    2000-12-01

    This paper surveys the modules and materials of blanket tritium-breeding zones developed in the Russian Federation for fusion reactors. Synthesis of lithium orthosilicate, metasilicate and aluminate, fabrication of ceramic pellets and pebbles and experimental reactor units are described. Results of tritium extraction kinetics under irradiation in a water-graphite reactor at a thermal neutron flux of 5×10 13 neutron/(s cm2) are considered. At the present time, development and fabrication of lithium orthosilicate-beryllium modules of the tritium-breeding zone (TBZ), have been carried out within the framework of the ITER and DEMO projects. Two modules containing orthosilicate pellets, porous beryllium and beryllium pebbles are suggested for irradiation tests in the temperature range of 350-700°C. Technical problems associated with manufacturing of the modules are discussed.

  7. Water and tritium movement through the unsaturated zone at a low-level radioactive-waste disposal site near Sheffield, Illinois, 1981-85

    USGS Publications Warehouse

    Mills, Patrick C.; Healy, Richard W.

    1993-01-01

    The movement of water and tritium through the unsaturated zone was studied at a low-level radioactive-waste disposal site near Sheffield, Bureau County, Illinois, from 1981 to 1985. Water and tritium movement occurred in an annual, seasonally timed cycle; recharge to the saturated zone generally occurred in the spring and early summer. Mean annual precipitation (1982-85) was 871 mm (millimeters); mean annual recharge to the disposal trenches (July 1982 through June 1984) was estimated to be 107 mm. Average annual tritium flux below the study trenches was estimated to be 3.4 mCi/yr (millicuries per year). Site geology, climate, and waste-disposal practices influenced the spatial and temporal variability of water and tritium movement. Of the components of the water budget, evapotranspiration contributed most to the temporal variability of water and tritium movement. Disposal trenches are constructed in complexly layered glacial and postglacial deposits that average 17 m (meters) in thickness and overlie a thick sequence of Pennsylvanian shale. The horizontal saturated hydraulic conductivity of the clayey-silt to sand-sized glacial and postglacial deposits ranges from 4.8x10 -1 to 3.4x10 4 mm/d (millimeters per day). A 120-m-long horizontal tunnel provided access for hydrologic measurements and collection of sediment and water samples from the unsaturated and saturated geologic deposits below four disposal trenches. Trench-cover and subtrench deposits were monitored with soil-moisture tensiometers, vacuum and gravity lysimeters, piezometers, and a nuclear soil-moisture gage. A cross-sectional, numerical ground-water-flow model was used to simulate water movement in the variably saturated geologic deposits in the tunnel area. Concurrent studies at the site provided water-budget data for estimating recharge to the disposal trenches. Vertical water movement directly above the trenches was impeded by a zone of compaction within the clayey-silt trench covers. Water entered

  8. Radiation dose estimation for marine mussels following exposure to tritium: Best practice for use of the ERICA tool in ecotoxicological studies.

    PubMed

    Dallas, Lorna J; Devos, Alexandre; Fievet, Bruno; Turner, Andrew; Lyons, Brett P; Jha, Awadhesh N

    2016-05-01

    Accurate dosimetry is critically important for ecotoxicological and radioecological studies on the potential effects of environmentally relevant radionuclides, such as tritium ((3)H). Previous studies have used basic dosimetric equations to estimate dose from (3)H exposure in ecologically important organisms, such as marine mussels. This study compares four different methods of estimating dose to adult mussels exposed to 1 or 15 MBq L(-1) tritiated water (HTO) under laboratory conditions. These methods were (1) an equation converting seawater activity concentrations to dose rate with fixed parameters; (2) input into the ERICA tool of seawater activity concentrations only; (3) input into the ERICA tool of estimated whole organism concentrations (woTACs), comprising dry activity plus estimated tissue free water tritium (TFWT) activity (TFWT volume × seawater activity concentration); and (4) input into the ERICA tool of measured whole organism activity concentrations, comprising dry activity plus measured TFWT activity (TFWT volume × TFWT activity concentration). Methods 3 and 4 are recommended for future ecotoxicological experiments as they produce values for individual animals and are not reliant on transfer predictions (estimation of concentration ratio). Method 1 may be suitable if measured whole organism concentrations are not available, as it produced results between 3 and 4. As there are technical complications to accurately measuring TFWT, we recommend that future radiotoxicological studies on mussels or other aquatic invertebrates measure whole organism activity in non-dried tissues (i.e. incorporating TFWT and dry activity as one, rather than as separate fractions) and input this data into the ERICA tool. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Tritium, stable isotopes, and nitrogen in flow from selected springs that discharge to the Snake River, Twin Falls-Hagerman area, Idaho, 1990-93

    USGS Publications Warehouse

    Mann, L.J.; Low, W.H.

    1994-01-01

    In 1990-93, water from 19 springs along the north side of the Snake River near Twin Falls and Hagerman contained from 9.2+0.6 to 78.4+5.1 picocuries per liter (pCi/L) of tritium. The springs were placed into three categories based on their locations and tritium concentrations: Category I was the upstream most and contained from 52.8+3.2 to 78.4+5.1 pCi/L of tritium; Category 11 was downstream from those in Category I and contained from 9.2+0.6 to 18.6+1.2 pCi/L; and Category III was the farthest downstream and contained from 28.3+1.9 to 47.7+3.2 pCi/L. Differences in tritium concentrations in the Category I, II, and III springs are a function of the ground-water flow regime, land use, and irrigation practices in and hydraulically upgradient from each category of springs. A comparatively large part of the water from the Category I springs is derived from recharge in heavily irrigated areas in which the irrigation water largely is diverted from the Snake River. A large part of the recharge for Category II springs occurs as much as 140 miles upgradient. Tritium concentrations in Category III springs indicate an intermediate proportion of the recharge is from excess applied-irrigation water. The concept that recharge from excess applied- irrigation water from the Snake River has affected tritium in the aquifer is supported by isotopic and nitrogen data. Deuterium and oxygen-18 isotopic values, and nitrite plus nitrate as nitrogen concentrations in the flow of some springs has been impacted by irrigation.

  10. Aggregation effects on tritium-based mean transit times and young water fractions in spatially heterogeneous catchments and groundwater systems

    NASA Astrophysics Data System (ADS)

    Stewart, Michael K.; Morgenstern, Uwe; Gusyev, Maksym A.; Małoszewski, Piotr

    2017-09-01

    Kirchner (2016a) demonstrated that aggregation errors due to spatial heterogeneity, represented by two homogeneous subcatchments, could cause severe underestimation of the mean transit times (MTTs) of water travelling through catchments when simple lumped parameter models were applied to interpret seasonal tracer cycle data. Here we examine the effects of such errors on the MTTs and young water fractions estimated using tritium concentrations in two-part hydrological systems. We find that MTTs derived from tritium concentrations in streamflow are just as susceptible to aggregation bias as those from seasonal tracer cycles. Likewise, groundwater wells or springs fed by two or more water sources with different MTTs will also have aggregation bias. However, the transit times over which the biases are manifested are different because the two methods are applicable over different time ranges, up to 5 years for seasonal tracer cycles and up to 200 years for tritium concentrations. Our virtual experiments with two water components show that the aggregation errors are larger when the MTT differences between the components are larger and the amounts of the components are each close to 50 % of the mixture. We also find that young water fractions derived from tritium (based on a young water threshold of 18 years) are almost immune to aggregation errors as were those derived from seasonal tracer cycles with a threshold of about 2 months.

  11. Efficiencies of Tritium (3H) bubbling systems.

    PubMed

    Duda, Jean-Marie; Le Goff, Pierre; Leblois, Yoan; Ponsard, Samuel

    2018-09-01

    Bubbling systems are among the devices most used by nuclear operators to measure atmospheric tritium activity in their facilities or the neighbouring environment. However, information about trapping efficiency and bubbling system oxidation is not accessible and/or, at best, only minimally supported by demonstrations in actual operating conditions. In order to evaluate easily these parameters and thereby meet actual normative and regulatory requirements, a statistical study was carried out over 2000 monitoring records from the CEA Valduc site. From this data collection obtained over recent years of monitoring the CEA Valduc facilities and environment, a direct relation was highlighted between the 3H-samplers trapping efficiency of tritium as tritiated water and the sampling time and conditions of use: temperature and atmospheric moisture. It was thus demonstrated that this efficiency originated from two sources. The first one is intrinsic to the bubbling system operating parameters and the sampling time. That part applies equally to all four bubblers. The second part, however, is specific to the first bubbler. In essence, it depends on the sampling time and the sampled air characteristics. It was also highlighted that the water volume variation in the first bubbler, between the beginning and the end of the sampling process, is directly related to the average water concentration of the sampled air. In this way, it was possible to model the variations in trapping efficiency of the 3H-samplers relative to the sampling time and the water volume variation in the first bubbler. This model makes it possible to obtain the quantities required to comply with the current standards governing the monitoring of radionuclides in the environment and to associate an uncertainty concerning the measurements as well as the sampling parameters. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Tritium permeation model for plasma facing components

    NASA Astrophysics Data System (ADS)

    Longhurst, G. R.

    1992-12-01

    This report documents the development of a simplified one-dimensional tritium permeation and retention model. The model makes use of the same physical mechanisms as more sophisticated, time-transient codes such as implantation, recombination, diffusion, trapping and thermal gradient effects. It takes advantage of a number of simplifications and approximations to solve the steady-state problem and then provides interpolating functions to make estimates of intermediate states based on the steady-state solution. The model is developed for solution using commercial spread-sheet software such as Lotus 123. Comparison calculations are provided with the verified and validated TMAP4 transient code with good agreement. Results of calculations for the ITER CDA diverter are also included.

  13. An overview of research activities on materials for nuclear applications at the INL Safety, Tritium and Applied Research facility

    NASA Astrophysics Data System (ADS)

    Calderoni, P.; Sharpe, J.; Shimada, M.; Denny, B.; Pawelko, B.; Schuetz, S.; Longhurst, G.; Hatano, Y.; Hara, M.; Oya, Y.; Otsuka, T.; Katayama, K.; Konishi, S.; Noborio, K.; Yamamoto, Y.

    2011-10-01

    The Safety, Tritium and Applied Research facility at the Idaho National Laboratory is a US Department of Energy National User Facility engaged in various aspects of materials research for nuclear applications related to fusion and advanced fission systems. Research activities are mainly focused on the interaction of tritium with materials, in particular plasma facing components, liquid breeders, high temperature coolants, fuel cladding, cooling and blanket structures and heat exchangers. Other activities include validation and verification experiments in support of the Fusion Safety Program, such as beryllium dust reactivity and dust transport in vacuum vessels, and support of Advanced Test Reactor irradiation experiments. This paper presents an overview of the programs engaged in the activities, which include the US-Japan TITAN collaboration, the US ITER program, the Next Generation Power Plant program and the tritium production program, and a presentation of ongoing experiments as well as a summary of recent results with emphasis on fusion relevant materials.

  14. Reanalysis of tritium production in a sphere of /sup 6/LiD irradiated by 14-MeV neutrons

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

    Fawcett, L.R. Jr.

    1985-08-01

    Tritium production and activation of radiochemical detector foils in a sphere of /sup 6/LiD irradiated by a central source of 14-MeV neutrons has been reanalyzed. The /sup 6/LiD sphere consisted of 10 solid hemispherical nested shells with ampules of /sup 6/LiH, /sup 7/LiH, and activation foils located 2.2, 5, 7.7, 12.6, 20, and 30 cm from the center. The Los Alamos Monte Carlo Neutron Photon Transport Code (MCNP) was used to calculate neutron transport through the /sup 6/LiD, tritium production in the ampules, and foil activation. The MCNP input model was three-dimensional and employed ENDF/B-V cross sections for transport, tritiummore » production, and (where available) foil activation. The reanalyzed experimentally observed-to-calculated values of tritium production were 1.053 +- 2.1% in /sup 6/LiH and 0.999 +- 2.1% in /sup 7/LiH. The recalculated foil activation observed-to-calculated ratios were not generally improved over those reported in the original analysis.« less

  15. Tritium Plume Dynamics in the Shallow Unsaturated Zone Adjacent to an Arid Waste Disposal Facility

    NASA Astrophysics Data System (ADS)

    Maples, S.; Andraski, B. J.; Stonestrom, D. A.; Cooper, C. A.; Michel, R. L.; Pohll, G. M.

    2012-12-01

    Previous studies at the U.S. Geological Survey's Amargosa Desert Research Site (ADRS) in southern Nevada have documented two plumes of tritiated water-vapor (3HHOg) adjacent to a closed, commercial low-level radioactive waste disposal facility. Wastes were disposed on-site from 1962-92. Tritium has moved long distances (> 400 m) through a shallow (1-2-m depth) dry gravelly layer—orders of magnitude further than anticipated by standard transport models. Geostatistical methods, spatial moment analyses and tritium flux calculations were applied to assess shallow plume dynamics. A grid-based plant-water sampling method was utilized to infer detailed, field-scale 3HHOg concentrations at 5-yr intervals during 2001-11. Results indicate that gravel-layer 3HHOg mass diminished faster than would be expected from radioactive decay (~70% in 10 yr). Both plumes exhibited center-of-mass stability, suggesting that bulk-plume movement is minimal during the period of study. Nonetheless, evidence of localized lateral advancement along some margins, combined with increases in the spatial covariance of concentration distribution, indicates intra-plume mass redistribution is ongoing. Previous studies have recognized that vertical movement of tritiated water from sub-root-zone gravel into the root-zone contributes to atmospheric release via evapotranspiration. Estimates of lateral and vertical tritium fluxes during the study period indicate (1) vertical tritiated water fluxes were dominated by diffusive-vapor fluxes (> 90%), and (2) vertical diffusive-vapor fluxes were roughly an order of magnitude greater than lateral diffusive-vapor fluxes. This behavior highlights the importance of the atmosphere as a tritium sink. Estimates of cumulative vertical diffusive-vapor flux and radioactive decay with time were comparable to observed declines in total shallow plume mass with time. This suggests observed changes in plume mass may (1) be attributed, in considerable part, to these removal

  16. Sandia, California Tritium Research Laboratory transition and reutilization project

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

    Garcia, T.B.

    1997-02-01

    This paper describes a project within Sandia National Laboratory to convert the shut down Tritium Research Laboratory into a facility which could be reused within the laboratory complex. In the process of decommissioning and decontaminating the facility, the laboratory was able to save substantial financial resources by transferring much existing equipment to other DOE facilities, and then expeditiously implementing a decontamination program which has resulted in the building being converted into laboratory space for new lab programs. This project of facility reuse has been a significant financial benefit to the laboratory.

  17. Near real-time analysis of tritium in treated water

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

    Skibo, A.

    The Tokyo Electric Power Company (TEPCO) is managing large quantities of treated water at the Fukushima Daiichi Nuclear Power Station. Moving forward, TEPCO will be discharging from the site clean water that meets agreed criteria. As part of agreements with stakeholders, TEPCO is planning to carefully monitor the water prior to discharge to assure compliance. The objective of this proposal is to support implementation of an on-line “real-time” (continuous or semi-continuous) tritium monitor that will reliably measure levels down to the agreed target 1500 Becquerels per liter (Bq/L).

  18. Total Transfer Capability Assessment Incorporating Corrective Controls for Transient Stability using TSCOPF

    NASA Astrophysics Data System (ADS)

    Hakim, Lukmanul; Kubokawa, Junji; Yorino, Naoto; Zoka, Yoshifumi; Sasaki, Yutaka

    Advancements have been made towards inclusion of both static and dynamic security into transfer capability calculation. However, to the authors' knowledge, work on considering corrective controls into the calculation has not been reported yet. Therefore, we propose a Total Transfer Capability (TTC) assessment considering transient stability corrective controls. The method is based on the Newton interior point method for nonlinear programming and transfer capability is approached as a maximization of power transfer with both static and transient stability constraints are incorporated into our Transient Stability Constrained Optimal Power Flow (TSCOPF) formulation. An interconnected power system is simulated to be subjected to a severe unbalanced 3-phase 4-line to ground fault and following the fault, generator and load are shed in a pre-defined sequence to mimic actual corrective controls. In a deregulated electricity market, both generator companies and large load customers are encouraged to actively participate in maintaining power system stability as corrective controls upon agreement of compensation for being shed following a disturbance. Implementation of this proposal on the actual power system operation should be carried out through combining it with the existing transient stabilization controller system. Utilization of these corrective controls results in increasing TTC as suggested in our numerical simulation. As Lagrange multipliers can also describe sensitivity of both inequality and equality constraints to the objective function, then selection of which generator or load to be shed can be carried out on the basis of values of Lagrange multipliers of its respective generator's rotor angle stability and active power balance equation. Hence, the proposal in this paper can be utilized by system operator to assess the maximum TTC for specific loads and network conditions.

  19. Comparison of balance of tritium activity in waste water from nuclear power plants and at selected monitoring sites in the Vltava River, Elbe River and Jihlava (Dyje) River catchments in the Czech Republic.

    PubMed

    Hanslík, Eduard; Marešová, Diana; Juranová, Eva; Sedlářová, Barbora

    2017-12-01

    During the routine operation, nuclear power plants discharge waste water containing a certain amount of radioactivity, whose main component is the artificial radionuclide tritium. The amounts of tritium released into the environment are kept within the legal requirements, which minimize the noxious effects of radioactivity, but the activity concentration is well measurable in surface water of the recipient. This study compares amount of tritium activity in waste water from nuclear power plants and the tritium activity detected at selected relevant sites of surface water quality monitoring. The situation is assessed in the catchment of the Vltava and Elbe Rivers, affected by the Temelín Nuclear Power Plant as well as in the Jihlava River catchment (the Danube River catchment respectively), where the waste water of the Dukovany Nuclear Power Plant is discharged. The results show a good agreement of the amount of released tritium stated by the power plant operator and the tritium amount detected in the surface water and highlighted the importance of a robust independent monitoring of tritium discharged from a nuclear power plant which could be carried out by water management authorities. The outputs of independent monitoring allow validating the values reported by a polluter and expand opportunities of using tritium as e.g. tracer. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. The incorporation of activities to control dengue by community health agents

    PubMed Central

    Cazola, Luiza Helena de Oliveira; Tamaki, Edson Mamoru; Pontes, Elenir Rose Jardim Cury; de Andrade, Sonia Maria Oliveira

    2014-01-01

    OBJECTIVE To evaluate the performance of Community Health Agents when dengue control activities were added to their tasks. METHODS Performance was measured comparing the evolution of selected indicators from the Brazilian National Dengue Control Program and the Family Health Strategy for 2002 to 2008 in the municipality of Sao Gabriel do Oeste, MS, Central Western Brazil, with those of Rio Verde de Mato Grosso, neighboring municipality with demographic, socioeconomic and health services similarities. Data were collected from municipal databases of the Information System for Yellow Fever and Dengue and the Information System for Primary Healthcare of the Mato Grosso do Sul State Health Office. The variables selected for the family health strategy activities were: monthly home visits, pregnant women whose antenatal care began in the first trimester, children under one with up-to-date vaccinations and hypertensive patients. Those selected for the Brazilian National Dengue Control Program were: properties inspected with Aedes aegypti and properties not inspected. RESULTS The two municipalities maintained a similar trend in dengue control indicators in the period studied. With regard to the Family Health Strategy, in 2002 Sao Gabriel do Oeste was better off in three of the four indicators studied, however, this situation was reversed at the end of the period when the county was overtaken by Rio Verde de Mato Grosso in three of the four indicators analyzed, including, the monthly average community health worker visits per registered family, the main activity of a Family Health Strategy agent. CONCLUSIONS: Incorporating the National Dengue Control Program into the Family Health Strategy is viable and developed without prejudice to dengue control activities, however, the same did not occur with the activities of family health in Sao Gabriel do Oeste. The additional workload of the community health workers is the most likely hypothesis for the declining performance of these

  1. Analysis of tritium production in concentric spheres of oralloy and /sup 6/LiD irradiated by 14-MeV neutrons

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

    Fawcett, L.R. Jr.; Roberts, R.R. II; Hunter, R.E.

    1988-03-01

    Tritium production and activation of radiochemical detector foils in a sphere of /sup 6/LiD with an oralloy core irradiated by a central source of 14-MeV neutrons have been calculated and compared with experimental measurements. The experimental assembly consisted of an oralloy sphere surrounded by three solid /sup 6/LiD concentric shells with ampules of /sup 6/LiH and /sup 7/LiH and activation foils located in several positions throughout the assembly. The Los Alamos Monte Carlo Neutron Photon Transport Code (MCNP) was used to calculate neutron transport throughout the system, tritium production in the ampules, and foil activation. The overall experimentally observed-to-calculated ratiosmore » of tritium production were 0.996 +- 2.5% in /sup 6/Li ampules and 0.903 +- 5.2% in /sup 7/Li ampules. Observed-to-calculated ratios for foil activation are also presented. 11 refs., 4 figs., 7 tabs.« less

  2. Evaluation of Elevated Tritium Levels in Groundwater Downgradient from the 618-11 Burial Ground Phase I Investigations

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

    Dresel, P.E.; Smith, R.M.; Williams, B.A.

    2000-05-01

    This report describes the results of the preliminary investigation of elevated tritium in groundwater discovered near the 618-11 burial ground, located in the eastern part of the Hanford Site. Tritium in one well downgradient of the burial ground was detected at levels up to 8,140,000 pCi/L. The 618-11 burial ground received a variety of radioactive waste from the 300 Area between 1962 and 1967. The burial ground covers 3.5 hectare (8.6 acre) and contains trenches, large diameter caissons, and vertical pipe storage units. The burial ground was stabilized with a native sediment covering. The Energy Northwest reactor complex was constructedmore » immediately east of the burial ground.« less

  3. Effect of tritium on corrosion behavior of chromium in 0.01 N sulfuric acid solution

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

    Oyaidzu, M.; Isobe, K.; Hayashi, T.

    The effects of tritium on the corrosion behavior of chromium in 0.01 N sulfuric solution have been investigated in the present study. Electrochemical experiments have been carried our for pure chromium. At first, the concentration dependence of sulfuric acid solution on anodic polarization behavior of chromium was experimented, resulting in that 0.01 N one was found appropriate. The dependence of both dissolved oxygen and tritium concentration on anodic behavior of chromium were performed. It was found from that the self-passivation of chromium induced by dissolved oxygen was inhibited in tritiated solution resulting in the enhancement of the corrosion. As amore » consequence it is highly likely that the elution of chromium by highly oxidative radiolysis products would explain the passivation inhibitory effect of SUS304 stainless steel observed in tritiated solutions.« less

  4. Ignition of deuterium-tritium fuel targets

    DOEpatents

    Musinski, D.L.; Mruzek, M.T.

    1991-08-27

    Disclosed is a method of igniting a deuterium-tritium ICF fuel target to obtain fuel burn in which the fuel target initially includes a hollow spherical shell having a frozen layer of DT material at substantially uniform thickness and cryogenic temperature around the interior surface of the shell. The target is permitted to free-fall through a target chamber having walls heated by successive target ignitions, so that the target is uniformly heated during free-fall to at least partially melt the frozen fuel layer and form a liquid single-phase layer or a mixed liquid/solid bi-phase layer of substantially uniform thickness around the interior shell surface. The falling target is then illuminated from exteriorly of the chamber while the fuel layer is at substantially uniformly single or bi-phase so as to ignite the fuel layer and release energy therefrom. 5 figures.

  5. Microstructure and yield strength effects on hydrogen and tritium induced cracking in HERF (high-energy-rate-forged) stainless steel

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

    Morgan, M J; Tosten, M H

    1989-01-01

    Rising-load J-integral measurements and falling-load threshold stress intensity measurements were used to characterize hydrogen and tritium induced cracking in high-energy-rate-forged (HERF) 21-6-9 stainless steel. Samples having yield strengths in the range 517--930 MPa were thermally charged with either hydrogen or tritium and tested at room temperature in either air or high-pressure hydrogen gas. In general, the hydrogen isotopes reduced the fracture toughness by affecting the fracture process. Static recrystallization in the HERF microstructures affected the material's fracture toughness and its relative susceptibility to hydrogen and tritium induced fracture. In hydrogen-exposed samples, the reduction in fracture toughness was primarily dependent onmore » the susceptibility of the microstructure to intergranular fracture and only secondarily affected by strength in the range of 660 to 930 MPa. Transmission-electron microscopy observations revealed that the microstructures least susceptible to hydrogen-induced intergranular cracking contained patches of fully recrystallized grains. These grains are surrounded by highly deformed regions containing a high number density of dislocations. The microstructure can best be characterized as duplex'', with soft recrystallized grains embedded in a hard, deformed matrix. The microstructures most susceptible to hydrogen-induced intergranular fracture showed no well-developed recrystallized grains. The patches of recrystallized grains seemed to act as crack barriers to hydrogen-induced intergranular fracture. In tritium-exposed-and-aged samples, the amount of static recrystallization also affected the fracture toughness properties but to a lesser degree. 7 refs., 25 figs.« less

  6. Fuel assembly for the production of tritium in light water reactors

    DOEpatents

    Cawley, W.E.; Trapp, T.J.

    1983-06-10

    A nuclear fuel assembly is described for producing tritium in a light water moderated reactor. The assembly consists of two intermeshing arrays of subassemblies. The first subassemblies comprise concentric annular elements of an outer containment tube, an annular target element, an annular fuel element, and an inner neutron spectrums shifting rod. The second subassemblies comprise an outer containment tube and an inner rod of either fuel, target, or neutron spectrum shifting neutral.

  7. Fuel assembly for the production of tritium in light water reactors

    DOEpatents

    Cawley, William E.; Trapp, Turner J.

    1985-01-01

    A nuclear fuel assembly is described for producing tritium in a light water moderated reactor. The assembly consists of two intermeshing arrays of subassemblies. The first subassemblies comprise concentric annular elements of an outer containment tube, an annular target element, an annular fuel element, and an inner neutron spectrums shifting rod. The second subassemblies comprise an outer containment tube and an inner rod of either fuel, target, or neutron spectrum shifting neutral.

  8. Tritium and radioactive carbon (14C) analyses of gas collected from unsaturated sediments next to a low-level radioactive-waste burial site south of Beatty, Nevada, April 1994 and July 1995

    USGS Publications Warehouse

    Prudic, David E.; Striegl, Robert G.

    1995-01-01

    Tritium activities in water vapor and radioactive carbon (14C) activities in carbon dioxide were determined in gas samples pumped from small-diameter air ports installed in a test hole within the unsaturated sediments next to a commercial burial site for low-level radioactive waste south of Beatty, Nevada. In April 1994, gas samples were collected from test hole UZB-2, which was drilled about 350 feet south of the southwest corner of the fence enclosing the burial site. The test hole is part of a study to determine the depth to which atmospheric air circulates through the unsaturated sediments at the desert site. Laboratory results completed in May 1995 show activities of tritium and 14C were greater than expected, with measured tritium in the water vapor as high as 762 tritium units at a depth of 79 feet and measured 14C in carbon dioxide as high as 1,700 percent modern carbon at a depth of 18 feet.In July 1995, the uppermost five air ports in test hole UZB-2 were resampled. In addition, water vapor was collected for tritium analyses at a distant test hole, and water vapor for tritium analyses and carbon dioxide for 14C analyses were collected from three depths at the research shaft about 200 feet north of test hole UZB-2, and at two shallow probes (depth of 5.5 feet) next to the fence enclosing the burial site. Analyses of samples collected in the upper 112 feet from test hole UZB-2 in July 1995 show the same distribution of tritium and 14C as analyses of samples collected in April 1994, except that activities were somewhat greater in July. The greatest activities of tritium and 14C were measured from a shallow probe next to the fence with activities of 29,400 tritium units and 517,000 percent modern carbon, respectively.

  9. False discovery rate control incorporating phylogenetic tree increases detection power in microbiome-wide multiple testing.

    PubMed

    Xiao, Jian; Cao, Hongyuan; Chen, Jun

    2017-09-15

    Next generation sequencing technologies have enabled the study of the human microbiome through direct sequencing of microbial DNA, resulting in an enormous amount of microbiome sequencing data. One unique characteristic of microbiome data is the phylogenetic tree that relates all the bacterial species. Closely related bacterial species have a tendency to exhibit a similar relationship with the environment or disease. Thus, incorporating the phylogenetic tree information can potentially improve the detection power for microbiome-wide association studies, where hundreds or thousands of tests are conducted simultaneously to identify bacterial species associated with a phenotype of interest. Despite much progress in multiple testing procedures such as false discovery rate (FDR) control, methods that take into account the phylogenetic tree are largely limited. We propose a new FDR control procedure that incorporates the prior structure information and apply it to microbiome data. The proposed procedure is based on a hierarchical model, where a structure-based prior distribution is designed to utilize the phylogenetic tree. By borrowing information from neighboring bacterial species, we are able to improve the statistical power of detecting associated bacterial species while controlling the FDR at desired levels. When the phylogenetic tree is mis-specified or non-informative, our procedure achieves a similar power as traditional procedures that do not take into account the tree structure. We demonstrate the performance of our method through extensive simulations and real microbiome datasets. We identified far more alcohol-drinking associated bacterial species than traditional methods. R package StructFDR is available from CRAN. chen.jun2@mayo.edu. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  10. Diagnosing radiative shocks from deuterium and tritium implosions on NIF.

    PubMed

    Pak, A; Divol, L; Weber, S; Döppner, T; Kyrala, G A; Kilne, J; Izumi, N; Glenn, S; Ma, T; Town, R P; Bradley, D K; Glenzer, S H

    2012-10-01

    During the recent ignition tuning campaign at the National Ignition Facility, layered cryogenic deuterium and tritium capsules were imploded via x-ray driven ablation. The hardened gated x-ray imager diagnostic temporally and spatially resolves the x-ray emission from the core of the capsule implosion at energies above ~8 keV. On multiple implosions, ~200-400 ps after peak compression a spherically expanding radiative shock has been observed. This paper describes the methods used to characterize the radial profile and rate of expansion of the shock induced x-ray emission.

  11. Subsurface Conditions Controlling Uranium Incorporation in Iron Oxides: A Redox Stable Sink

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

    Fendorf, Scott

    2016-04-05

    Toxic metals and radionuclides throughout the U.S. Department of Energy Complex pose a serious threat to ecosystems and to human health. Of particular concern is the redox-sensitive radionuclide uranium, which is classified as a priority pollutant in soils and groundwaters at most DOE sites owing to its large inventory, its health risks, and its mobility with respect to primary waste sources. The goal of this research was to contribute to the long-term mission of the Subsurface Biogeochemistry Program by determining reactions of uranium with iron (hydr)oxides that lead to long-term stabilization of this pervasive contaminant. The research objectives of thismore » project were thus to (1) identify the (bio)geochemical conditions, including those of the solid-phase, promoting uranium incorporation in Fe (hydr)oxides, (2) determine the magnitude of uranium incorporation under a variety of relevant subsurface conditions in order to quantify the importance of this pathway when in competition with reduction or adsorption; (3) identify the mechanism(s) of U(VI/V) incorporation in Fe (hydr)oxides; and (4) determine the stability of these phases under different biogeochemical (inclusive of redox) conditions. Our research demonstrates that redox transformations are capable of achieving U incorporation into goethite at ambient temperatures, and that this transformation occurs within days at U and Fe(II) concentrations that are common in subsurface geochemical environments with natural ferrihydrites—inclusive of those with natural impurities. Increasing Fe(II) or U concentration, or initial pH, made U(VI) reduction to U(IV) a more competitive sequestration pathway in this system, presumably by increasing the relative rate of U reduction. Uranium concentrations commonly found in contaminated subsurface environments are often on the order of 1-10 μM, and groundwater Fe(II) concentrations can reach exceed 1 mM in reduced zones of the subsurface. The redox-driven U

  12. New data on the level of contamination with tritium aerosol fallout in the nearest influence zone of the mining-chemical combine of the Rosatom State Corporation

    NASA Astrophysics Data System (ADS)

    Bondareva, L. G.; Rubailo, A. I.

    2016-03-01

    The influence of tritium aerosol transport on radioactive contamination on the territory of the Krasnoyarsk region influenced by the mining-chemical combine of the Rosatom State Corporation was studied. Snow cover, foliage, and needles collected at various distances from the mining-chemical combine were selected as the object of this study. A new methodology of liquid extraction from plant material (leaves and needles) was worked out. As a result, the maximal concentrations of tritium (15 kBk/m3 in snow, 11 and 15 Bk/m2 for leaves and pine-tree needles, respectively) were determined. However, the results obtained are not anomalous. Consequently, contamination with tritium may not be accounted for entirely due to the low concentrations.

  13. Overview of transport, fast particle and heating and current drive physics using tritium in JET plasmas

    NASA Astrophysics Data System (ADS)

    Stork, D.; Baranov, Yu.; Belo, P.; Bertalot, L.; Borba, D.; Brzozowski, J. H.; Challis, C. D.; Ciric, D.; Conroy, S.; de Baar, M.; de Vries, P.; Dumortier, P.; Garzotti, L.; Hawkes, N. C.; Hender, T. C.; Joffrin, E.; Jones, T. T. C.; Kiptily, V.; Lamalle, P.; Mailloux, J.; Mantsinen, M.; McDonald, D. C.; Nave, M. F. F.; Neu, R.; O'Mullane, M.; Ongena, J.; Pearce, R. J.; Popovichev, S.; Sharapov, S. E.; Stamp, M.; Stober, J.; Surrey, E.; Valovic, M.; Voitsekhovitch, I.; Weisen, H.; Whiteford, A. D.; Worth, L.; Yavorskij, V.; Zastrow, K.-D.; EFDA contributors, JET

    2005-10-01

    Results are presented from the JET Trace Tritium Experimental (TTE) campaign using minority tritium (T) plasmas (nT/nD < 3%). Thermal tritium particle transport coefficients (DT, vT) are found to exceed neo-classical values in all regimes, except in ELMy H-modes at high densities and in the region of internal transport barriers (ITBs) in reversed shear plasmas. In ELMy H-mode dimensionless parameter scans, at q95 ~ 2.8 and triangularity δ = 0.2, the T particle transport scales in a gyro-Bohm manner in the inner plasma (r/a < 0.4), whilst the outer plasma particle transport scaling is more Bohm-like. Dimensionless parameter scans show contrasting behaviour for the trace particle confinement (increases with collisionality, ν* and β) and bulk energy confinement (decreases with ν* and is independent of β). In an extended ELMy H-mode data set, with ρ*, ν*, β and q varied but with neo-classical tearing modes (NTMs) either absent or limited to weak, benign core modes (4/3 or above), the multiparameter fit to the normalized diffusion coefficient in the outer plasma (0.65 < r/a < 0.8) gives DT/Bphi ~ ρ*2.46ν*-0.23β-1.01q2.03. In hybrid scenarios (qmin ~ 1, low positive shear, no sawteeth), the T particle confinement is found to scale with increasing triangularity and plasma current. Comparing regimes (ELMy H-mode, ITB plasma and hybrid scenarios) in the outer plasma region, a correlation of high values of DT with high values of vT is seen. The normalized diffusion coefficients for the hybrid and ITB scenarios do not fit the scaling derived for ELMy H-modes. The normalized tritium diffusion scales with normalized poloidal Larmor radius (\\rho_{\\theta}^\\ast=q\\rho^{\\ast}) in a manner close to gyro-Bohm ({\\sim}\\rho_{\\theta}^{\\ast 3}) , with an added inverse β dependence. The effects of ELMs, sawteeth and NTMs on the T particle transport are described. Fast-ion confinement in current-hole (CH) plasmas was tested in TTE by tritium neutral beam injection into

  14. Radioactive emission data from Canadian nuclear generating stations, 1988 to 1997. Report number INFO-0210/Rev.8

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

    NONE

    1998-12-31

    This edition incorporates histograms for each nuclear generating station (NGS) displaying the annual gaseous emissions containing tritium, in the form of tritium oxide, noble gases, iodine-131, and radioactive particulates, as well as the annual liquid emissions containing tritium, in the form of tritiated water, and gross beta-gamma activity. For Pickering NGS A and Gentilly 2, annual emissions of carbon-14 are depicted; and for Darlington NGS A, airborne emissions of elemental tritium since 1988 are shown. In each case, the emission data are compared to the derived emission limits.

  15. Tritium technology development in EEC laboratories contributions to design goals for NET

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

    Dinner, P.; Chazalon, M.; Leger, D.

    1988-09-01

    An overview is given of the tritium technology activities carried out in the European national laboratories associated with the European Fusion Programme and in the European Joint Research Center. The relationship of these activities to the Next European Torus (NET) design priorities is discussed, and the current status of the research is summarised. Future developments, required for NET, which will be addressed in the definition of the next 5-year programme are also presented.

  16. Investigating drought vulnerability using stable water isotopes and tritium in a montane system

    NASA Astrophysics Data System (ADS)

    Thaw, Melissa; Visser, Ate; Deinhart, Amanda; Bibby, Richard; Everhart, Anthony; Sharp, Mike; Conklin, Martha

    2017-04-01

    We combined measurements of water stable isotopes (d18O and d2H) with measurements of tritium (3H) to track water from precipitation through the subsurface and vegetation. Our study examined drought vulnerability in terms of vegetation water sources and subsurface storage in two montane sites, seasonally, using stable isotopes and tritium. Relative proportions of evapotranspiration sources were determined using two-tracer (d18O and 3H), three component mixing models. The two sites, located in the Southern Sierra Critical Zone Observatory, California, USA, are Mediterranean in climate, straddling the rain-snow transition zone where the upper elevation site receives most of its precipitation as winter snow. Over the study period, summer 2015 followed four years of severe snow drought; summer 2016 followed a slightly below average winter. The lower elevation site experienced severe drought-induced tree mortality over this time. Preliminary results show severe snow drought conditions and summer precipitation affected the proportions of source water used by vegetation due to the ability of vegetation to change sources when new water became available. Both stable isotopes and tritium reflect seasonal shifts in vegetation water sources, as well as species vulnerability and tolerance to drought. Xylem water sampled from Abies concolor (white fir) and Arctostaphylos patula (manzanita) responded the most quickly to changes in available water sources compared to Pinus jeffreyi (Jeffrey pine) and Calocedrus decurrens (incense cedar). Abies concolor and Arctostaphylos patula responded more dramatically to summer soil evaporation by accessing summer rain and deep water sources more quickly. Abies concolor also responded more dramatically to changes in snowpack during winter. During severe drought conditions, Arctostaphylos's ability to tap into a wide range of water sources coincided with drought tolerance (100% survival rate), while mortality for Pinus ponderosa and Calocedrus

  17. Controlled-release of tea polyphenol from gelatin films incorporated with different ratios of free/nanoencapsulated tea polyphenols into fatty food simulants

    USDA-ARS?s Scientific Manuscript database

    Gelatin films having controlled-release properties were developed by incorporation of different free/encapsulated tea polyphenol (TP) ratios through modifying the encapsulation efficiency (EE) of TP-loaded chitosan nanoparticles. Different EEs were obtained by adjusting the chitosan hydrochloride (C...

  18. Tritium Separation from High Volume Dilute Aqueous Streams- Milestone Report for M3FT-15OR0302092

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

    Bhave, Ramesh R.; Jubin, Robert Thomas; Spencer, Barry B.

    2016-02-29

    This report describes the synthesis and evaluation of molecular sieve zeolite membranes to separate and concentrate tritiated water (HTO) from dilute HTO-bearing aqueous streams. Several silico alumino phosphate (SAPO-34) molecular sieve zeolite membranes were synthesized and characterized with gas and vapor permeation measurements. The pervaporation process performance was evaluated for the separation and concentration of tritiated water. Experiments were performed over a range of tritiated water concentration covering the range of concentration anticipated in nuclear fuel processing where potentially both acid and water streams are recycled. The permeate was recovered under vacuum. The tritium concentration ranged from 0.5 to 1more » mCi/mL which is about 0.1 mg/L or 0.1 ppm. The HTO concentration was three orders of magnitude lower than experiments performed with simulated feed containing HDO (>100 ppm) using deuterated water where high separation factors (>10) were obtained using SAPO membranes. Separation factor calculated from the measured tritium concentrations ranged from 0.83-0.98. Although the membrane performance characterization results were lower than expected, they can be explained on the basis of low feed volume and three orders of magnitude lower HTO concentration compared to HDO concentration in deuterated water. We have identified several new approaches, such as tuning the diffusion coefficient of HTO, that may help achieve preferential transport of tritium (HTO) resulting in a substantially more concentrated permeate.« less

  19. Experimental detection and investigation of muon catalyzed fusion of deuterium and tritium

    NASA Astrophysics Data System (ADS)

    Bystritsky, V. M.; Dzhelepov, V. P.; Ershova, Z. V.; Filchenkov, V. V.; Kapyshev, V. K.; Mukhamet-Galeeva, S. M.; Nadezhdin, V. S.; Rivkis, L. A.; Rudenko, A. I.; Satarov, V. I.; Sergeeva, N. V.; Somov, L. N.; Stolupin, V. A.; Zinov, V. G.

    1980-08-01

    Measurement of the neutron yield of the reaction dtμ → 4He + μ - + 17.6 MeV, induced by negative muons in a mixture of gaseous D 2 and T 2, has shown that the rate of muon transfer from deuterium to tritium is λdt = (2.7 ± 0.9) × 10 8s -1 and that the lower limit of the formation rate of dt μ molecules is λdtμ > 10 8s -1.

  20. Proton-Proton Fusion and Tritium β Decay from Lattice Quantum Chromodynamics

    NASA Astrophysics Data System (ADS)

    Savage, Martin J.; Shanahan, Phiala E.; Tiburzi, Brian C.; Wagman, Michael L.; Winter, Frank; Beane, Silas R.; Chang, Emmanuel; Davoudi, Zohreh; Detmold, William; Orginos, Kostas; Nplqcd Collaboration

    2017-08-01

    The nuclear matrix element determining the p p →d e+ν fusion cross section and the Gamow-Teller matrix element contributing to tritium β decay are calculated with lattice quantum chromodynamics for the first time. Using a new implementation of the background field method, these quantities are calculated at the SU(3) flavor-symmetric value of the quark masses, corresponding to a pion mass of mπ˜806 MeV . The Gamow-Teller matrix element in tritium is found to be 0.979(03)(10) at these quark masses, which is within 2 σ of the experimental value. Assuming that the short-distance correlated two-nucleon contributions to the matrix element (meson-exchange currents) depend only mildly on the quark masses, as seen for the analogous magnetic interactions, the calculated p p →d e+ν transition matrix element leads to a fusion cross section at the physical quark masses that is consistent with its currently accepted value. Moreover, the leading two-nucleon axial counterterm of pionless effective field theory is determined to be L1 ,A=3.9 (0.2 )(1.0 )(0.4 )(0.9 ) fm3 at a renormalization scale set by the physical pion mass, also agreeing within the accepted phenomenological range. This work concretely demonstrates that weak transition amplitudes in few-nucleon systems can be studied directly from the fundamental quark and gluon degrees of freedom and opens the way for subsequent investigations of many important quantities in nuclear physics.

  1. Measurement of Tritium in Gas Phase Soil Moisture and Helium-3 in Soil Gas at the Hanford Townsite and 100 K Area

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

    KB Olsen; GW Patton; R Poreda

    2000-07-05

    In 1999, soil gas samples for helium-3 measurements were collected at two locations on the Hanford Site. Eight soil gas sampling points ranging in depth from 1.5 to 9.8 m (4.9 to 32 ft) below ground surface (bgs) in two clusters were installed adjacent to well 699-41-1, south of the Hanford Townsite. Fifteen soil gas sampling points, ranging in depth from 2.1 to 3.2 m (7 to 10.4 ft) bgs, were installed to the north and east of the 100 KE Reactor. Gas phase soil moisture samples were collected using silica gel traps from all eight sampling locations adjacent tomore » well 699-41-1 and eight locations at the 100 K Area. No detectable tritium (<240 pCi/L) was found in the soil moisture samples from either the Hanford Townsite or 100 K Area sampling points. This suggests that tritiated moisture from groundwater is not migrating upward to the sampling points and there are no large vadose zone sources of tritium at either location. Helium-3 analyses of the soil gas samples showed significant enrichments relative to ambient air helium-3 concentrations with a depth dependence consistent with a groundwater source from decay of tritium. Helium-3/helium-4 ratios (normalized to the abundances in ambient air) at the Hanford Townsite ranged from 1.012 at 1.5 m (5 ft) bgs to 2.157 at 9.8 m (32 ft) bgs. Helium-3/helium-4 ratios at the 100 K Area ranged from 0.972 to 1.131. Based on results from the 100 K Area, the authors believe that a major tritium plume does not lie within that study area. The data also suggest there may be a tritium groundwater plume or a source of helium-3 to the southeast of the study area. They recommend that the study be continued by placing additional soil gas sampling points along the perimeter road to the west and to the south of the initial study area.« less

  2. Radiochemical Reactions Between Tritium Molecule and Carbon Dioxide

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

    Shu, W.M.; O'Hira, S.; Suzuki, T.

    To have better understanding of radiochemical reactions among oxygen baking products in a fusion reactor, reactions in equimolar tritium molecule (T{sub 2}) and carbon dioxide (CO{sub 2}) were examined by laser Raman spectroscopy and mass spectrometry. After mixing them at room temperature, T{sub 2} and CO{sub 2} decreased rapidly in the first 30 minutes and then the reactions between them became much slower. As the predominant products of the reactions, carbon monoxide (CO) and tritiated water (T{sub 2}O) were found in gaseous phase and condensed phase, respectively. However, there likely existed also some solid products that were thermally decomposed intomore » CO, CO{sub 2}, T{sub 2}, T{sub 2}O, etc. during baking up to 523 K.« less

  3. Potential effects of incorporating fertility control into typical culling regimes in wild pig populations

    PubMed Central

    Davis, Amy J.; Cunningham, Fred L.; VerCauteren, Kurt C.; Eckery, Doug C.

    2017-01-01

    Effective management of widespread invasive species such as wild pigs (Sus scrofa) is limited by resources available to devote to the effort. Better insight of the effectiveness of different management strategies on population dynamics is important for guiding decisions of resource allocation over space and time. Using a dynamic population model, we quantified effects of culling intensities and time between culling events on population dynamics of wild pigs in the USA using empirical culling patterns and data-based demographic parameters. In simulated populations closed to immigration, substantial population declines (50–100%) occurred within 4 years when 20–60% of the population was culled annually, but when immigration from surrounding areas occurred, there was a maximum of 50% reduction, even with the maximum culling intensity of 60%. Incorporating hypothetical levels of fertility control with realistic culling intensities was most effective in reducing populations when they were closed to immigration and when intrinsic population growth rate was too high (> = 1.78) to be controlled by culling alone. However, substantial benefits from fertility control used in conjunction with culling may only occur over a narrow range of net population growth rates (i.e., where net is the result of intrinsic growth rates and culling) that varies depending on intrinsic population growth rate. The management implications are that the decision to use fertility control in conjunction with culling should rely on concurrent consideration of achievable culling intensity, underlying demographic parameters, and costs of culling and fertility control. The addition of fertility control reduced abundance substantially more than culling alone, however the effects of fertility control were weaker than in populations without immigration. Because these populations were not being reduced substantially by culling alone, fertility control could be an especially helpful enhancement to culling

  4. Auxin Does Not Alter the Permeability of Pea Segments to Tritium-labeled Water.

    PubMed

    Dowler, M J; Rayle, D L

    1974-02-01

    The possibility of an auxin effect on the permeability of pea (Pisum sativum L. ev. Alaska) segments to tritium-labeled water has been investigated by three separate laboratories, and the combined results are presented. We were unable to obtain any indication of a rapid effect of indoleacetic acid on the efflux of (3)HHO when pea segments previously "loaded" for 90 minutes with (3)HHO were transferred to unlabeled aqueous medium with indoleacetic acid. We were able to confirm that segments pretreated with (3)HHO plus indoleacetic acid for 60 to 90 minutes can show an enhanced (3)HHO release as compared with minus indoleacetic acid controls. However, this phenomenon appears to be due to an increased uptake of (3)HHO during the prolonged indoleacetic acid pretreatment, and therefore we conclude that auxin does not alter the permeability of pea segments to (3)HHO in either short term or long term tests. We confirm previous reports that the uptake of (3)HHO in pea segments proceeds largely through the cut surfaces, and that the cuticle is a potent barrier to (3)HHO flux.

  5. Tom Bonner Prize Lecture: The Beta Spectrum of Tritium and the Problem of Neutrino Mass

    NASA Astrophysics Data System (ADS)

    Robertson, R. G. Hamish

    1997-04-01

    Enrico Fermi showed more than 60 years ago that the shape of beta spectra was sensitive to the mass of the unobserved particle, the neutrino, proposed by Wolfgang Pauli. With the discovery of tritium and its small decay energy, increasingly stringent limits were placed on the electron antineutrino mass. A roadblock at about 50 eV, namely the atomic and molecular structure of tritium-containing substances, was surmounted in the 1980s with the development at Los Alamos of methods for high-resolution beta spectroscopy with gases, together with worldwide theoretical work on the structure of diatomic T2 and T^3He^+. It was then possible to reach the very interesting region of cosmological relevance below 20 eV. An unexpected and strange new roadblock has now been encountered in all experiments on T_2. The spectrum near the endpoint is not consistent with theory either with or without neutrino mass. The questions now are, do the experiments all report the same phenomenon, and (if so) is it atomic theory, particle theory, or perhaps cosmology that needs repair?

  6. Intra-annual variations in atmospheric dust and tritium in the North Pacific region detected from an ice core from Mount Wrangell, Alaska

    NASA Astrophysics Data System (ADS)

    Yasunari, Teppei J.; Shiraiwa, Takayuki; Kanamori, Syosaku; Fujii, Yoshiyuki; Igarashi, Makoto; Yamazaki, Koji; Benson, Carl S.; Hondoh, Takeo

    2007-05-01

    The North Pacific is subject to various seasonal climate phenomena and material circulations. Therefore intra-annual ice core data are necessary for an assessment of the climate variations. To assess past variations, a 50-m ice core was drilled at the summit of Mount Wrangell Volcano, Alaska. The dust number, tritium concentrations, and stable hydrogen isotope were analyzed. The period covered was from 1992 to 2002. We found that the concentrations of both fine dust (0.52-1.00 μm), an indicator of long-range transport, and coarse dust (1.00-8.00 μm) increased together every spring. Moreover, their concentrations increased drastically after 2000, corresponding to the recent increase in Asian dust outbreaks in spring. Additionally, an increase in the spring of 2001 corresponded to the largest dust storm recorded in east Asia since 1979. Therefore our findings imply that Asian dust strongly polluted Mount Wrangell every spring. The stratospheric tracer, tritium, had late spring maxima almost every year, and we found this useful for ice core dating to identify late spring in the North Pacific region. We also found that a high positive annual correlation existed between the calculated tritium and fine dust fluxes from late spring to summer. We propose that an annual relationship between the stratosphere-troposphere exchange and Asian dust storm are most closely connected in late spring because their activities are weak in summer. The Mount Wrangell ice core is important and useful for assessing the dust and tritium circulation in the distant past around the North Pacific with probable intra-annual timescale information.

  7. Preparation of tritium-labeled optical isomers of amino acids by ligand exchange chromatography on polyacrylamide sorbent containing L-phenylalanine groupings

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

    Zolotarev, Yu.A.; Penkina, V.I.; Dostavalov, I.N.

    Tritium-labeled optically active amino acids are obtained by resolving racemates of the corresponding amino acids by chromatography on a chiral polyacrylamide sorbent, filled with copper ions. The chiral sorbent is obtained by the action of formaldehyde and L-phenylalanine on a Biogel P-4 polyacrylamide gel in an alkaline medium. Data are given on the ligand exchange chromatography of amino acids on this sorbent, depending on the degree of filling of the sorbent by copper ions and the concentration of the eluent. Conditions were selected for the quantitative resolution of racemates of amino acids and examples are given of a preparative obtainingmore » of tritium labeled optical isomers of amino acids.« less

  8. 10 CFR 32.22 - Self-luminous products containing tritium, krypton-85 or promethium-147: Requirements for license...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... promethium-147: Requirements for license to manufacture, process, produce, or initially transfer. 32.22 Section 32.22 Energy NUCLEAR REGULATORY COMMISSION SPECIFIC DOMESTIC LICENSES TO MANUFACTURE OR TRANSFER... containing tritium, krypton-85 or promethium-147: Requirements for license to manufacture, process, produce...

  9. Effectiveness of insecticide-incorporated bags to control stored-product beetles

    USDA-ARS?s Scientific Manuscript database

    Adults of seven stored-product beetle species were exposed on the inside and outside surfaces of polypropylene polymer bags incorporated with the insecticide deltamethrin (approx. concentration of 3,000 ppm; ZeroFly® Storage Bags (3g/kg). Beetles were exposed for 60, 120, and 180 min, and 1, 3 and 5...

  10. First results of radiation-driven, layered deuterium-tritium implosions with a 3-shock adiabat-shaped drive at the National Ignition Facility

    DOE PAGES

    Smalyuk, V. A.; Robey, H. F.; Döppner, T.; ...

    2015-08-27

    Radiation-driven, layered deuterium-tritium plastic capsule implosions were carried out using a new, 3-shock “adiabat-shaped” drive on the National Ignition Facility. The purpose of adiabat shaping is to use a stronger first shock, reducing hydrodynamic instability growth in the ablator. The shock can decay before reaching the deuterium-tritium fuel leaving it on a low adiabat and allowing higher fuel compression. The fuel areal density was improved by ~25% with this new drive compared to similar “high-foot” implosions, while neutron yield was improved by more than 4 times, compared to “low-foot” implosions driven at the same compression and implosion velocity.

  11. Tritium and 36Cl as constraints on fast fracture flow and percolation flux in the unsaturated zone at Yucca Mountain.

    PubMed

    Guerin, M

    2001-10-01

    An analysis of tritium and 36Cl data collected at Yucca Mountain, Nevada suggests that fracture flow may occur at high velocities through the thick unsaturated zone. The mechanisms and extent of this "fast flow" in fractures at Yucca Mountain are investigated with data analysis, mixing models and several one-dimensional modeling scenarios. The model results and data analysis provide evidence substantiating the weeps model [Gauthier, J.H., Wilson, M.L., Lauffer, F.C., 1992. Proceedings of the Third Annual International High-level Radioactive Waste Management Conference, vol. 1, Las Vegas, NV. American Nuclear Society, La Grange Park, IL, pp. 891-989] and suggest that fast flow in fractures with minimal fracture-matrix interaction may comprise a substantial proportion of the total infiltration through Yucca Mountain. Mixing calculations suggest that bomb-pulse tritium measurements, in general, represent the tail end of travel times for thermonuclear-test-era (bomb-pulse) infiltration. The data analysis shows that bomb-pulse tritium and 36Cl measurements are correlated with discrete features such as horizontal fractures and areas where lateral flow may occur. The results presented here imply that fast flow in fractures may be ubiquitous at Yucca Mountain, occurring when transient infiltration (storms) generates flow in the connected fracture network.

  12. Tritium and 36Cl as constraints on fast fracture flow and percolation flux in the unsaturated zone at Yucca Mountain

    NASA Astrophysics Data System (ADS)

    Guerin, Marianne

    2001-10-01

    An analysis of tritium and 36Cl data collected at Yucca Mountain, Nevada suggests that fracture flow may occur at high velocities through the thick unsaturated zone. The mechanisms and extent of this "fast flow" in fractures at Yucca Mountain are investigated with data analysis, mixing models and several one-dimensional modeling scenarios. The model results and data analysis provide evidence substantiating the weeps model [Gauthier, J.H., Wilson, M.L., Lauffer, F.C., 1992. Proceedings of the Third Annual International High-level Radioactive Waste Management Conference, vol. 1, Las Vegas, NV. American Nuclear Society, La Grange Park, IL, pp. 891-989] and suggest that fast flow in fractures with minimal fracture-matrix interaction may comprise a substantial proportion of the total infiltration through Yucca Mountain. Mixing calculations suggest that bomb-pulse tritium measurements, in general, represent the tail end of travel times for thermonuclear-test-era (bomb-pulse) infiltration. The data analysis shows that bomb-pulse tritium and 36Cl measurements are correlated with discrete features such as horizontal fractures and areas where lateral flow may occur. The results presented here imply that fast flow in fractures may be ubiquitous at Yucca Mountain, occurring when transient infiltration (storms) generates flow in the connected fracture network.

  13. Implementation of Tritium in the Lmdz-Iso General Circulation Model: First Promising Results for the Study of the Relationships Between Stratospheric Air Inputs into the Lower Troposphere in Polar Regions, Water Cycle and Climate

    NASA Astrophysics Data System (ADS)

    Cauquoin, A.; Jean Baptiste, P.; Risi, C. M.; Fourre, E.; Landais, A.

    2014-12-01

    Understanding the links between climate and water cycle is essential in the current context of global warming. The water isotopic composition, quantified as δD, δ18O or δ17O, has a great potential to trace the organization of present-day hydrological cycle. When recorded in various archives as tree rings, sediments, ice cores, they have also been largely used to reconstruct the past evolution of climate and water. The Antarctic cap is extremely sensitive to climate change. Moreover, this region is under the influence of exchanges between the troposphere and the stratosphere because of the presence of the polar vortex. Tritium (3H) has been shown to be an appropriate tracer for the intrusion of stratospheric air masses into the lower troposphere. Natural tritium is mainly produced by the interaction of cosmic radiations with the upper atmosphere. This tritium enters the hydrological cycle in the form of tritiated water molecules (HTO) and has a radioactive half-life of 4500±8 days. In an approach combining data and model, we have first implemented tritium in the coupled Laboratoire de Météorologie Dynamique Zoom (LMDZ) Atmospheric General Circulation Model developed at IPSL [Risi et al., 2010]: LMDZ-iso. The implementation of natural tritium uses the same model architecture as for the other water isotopes, after a correct description of associated cosmogenic production terms [Masarik and Beer, 2009]. The model is used in a configuration dedicated to the simulation of the stratosphere, with 39 layers. In this presentation, we will focus on the modeling of spatial and temporal natural variations of tritium content in precipitation. The model is validated against a compilation of available data for natural tritium. We show that the continental and latitudinal effects are well reproduced by the model and that simulated seasonal variations of the tritium content of precipitation are coherent with our current knowledge of troposphere-stratosphere exchanges. Masarik

  14. Gold nanoparticle incorporated polymer/bioactive glass composite for controlled drug delivery application.

    PubMed

    Jayalekshmi, A C; Sharma, Chandra P

    2015-02-01

    The present study discusses the development of a biodegradable polymer encapsulated-nanogold incorporated-bioactive glass composite (AuPBG) by a low-temperature method. The composite was analyzed by atomic force microscopy (AFM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry (TG), fluorescence and dissolution analysis. The composite exhibited aggregation behaviour in solid and solution states and exhibited negative zeta potential (-13.3 ± 1.4 mV). The composite exhibited fast degradation starting from the 5(th) day onwards in phosphate buffered saline (PBS) for a period of 14 days. The composite showed fluorescence quenching effect at pH 7 and the fluorescence recovered at pH 5. The composite has been found to be suitable for the release of doxorubicin at high rates at acidic pH (∼ 5) which is the intracellular pH of tumour cells. The drug loading ratio is also high and it exhibited a controlled release for a period of 8 days in PBS. The system serves as a promising material for targeted drug delivery applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Biodegradable thermoplastic polyurethanes incorporating polyhedral oligosilsesquioxane.

    PubMed

    Knight, Pamela T; Lee, Kyung Min; Qin, Haihu; Mather, Patrick T

    2008-09-01

    A new hybrid thermoplastic polyurethane (TPU) system that incorporates an organic, biodegradable poly(D, L-lactide) soft block with a hard block bearing the inorganic polyhedral oligosilsesquioxane (POSS) moiety is introduced and studied. Changes in the polyol composition made through variation of the hydrophilic initiator molecular weight show direct control of the final transition temperatures. Incorporating POSS into the hard segments allows for excellent elasticity above T(g), as evidenced with dynamic mechanical analysis, not seen in most other biodegradable materials. This elasticity is attributed to physical cross-links formed in the hard block through POSS crystallization, as revealed with wide-angle X-ray diffraction. Increasing the POSS incorporation level in the TPU hard block was observed to increase crystallinity and also the rigidity of the material. The highest incorporation, using a statistical average of three POSS units per hard block, demonstrated one-way shape memory with excellent shape fixing capabilities. In vitro degradation of this sample was also investigated during a two month period. Moderate water uptake and dramatic molecular weight decrease were immediately observed although large mass loss (approximately 20 wt %) was not observed until the two month time point.

  16. Glycation of human lens proteins: preferential glycation of alpha A subunits.

    PubMed

    Swamy, M S; Abraham, A; Abraham, E C

    1992-03-01

    Glycation of crystallins and high molecular weight (HMW) aggregates was followed during aging (16-85 years) and in diabetes (44 and 70 years old). Lens soluble and insoluble fractions were reduced with [3H]NaBH4 and separated by molecular sieve HPLC. The protein content in each HPLC peak was measured by the Lowry method. The tritium incorporation, expressed as cpm mg-1 protein, was taken as a measure of early glycation and specific non-tryptophan fluorescence (Ex: 370 nm; Em: 440 nm), expressed as relative fluorescence U mg-1 protein, was taken as a measure of advanced glycation. The youngest lenses analysed were 16 and 17 years old and these provided the baseline values. The results showed that during aging there was about a three-fold increase in tritium incorporation and fluorescence of alpha-crystallin, while the increases in beta and gamma were only two-fold from the levels seen in 16- and 17-year-old lenses. On the other hand, both the soluble and insoluble HMW aggregate fractions showed up to five-fold increase in tritium incorporation during aging. The fluorescence was about two-fold higher in the insoluble HMW aggregates as compared to the soluble HMW aggregates in 16- and 17-year-old lenses and both showed an increase of about three-fold during aging. Diabetes resulted in an approximately 10-50% increase in tritium incorporation and non-tryptophan fluorescence of various crystallins and HMW aggregates.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Detailed implosion modeling of deuterium-tritium layered experiments on the National Ignition Facilitya)

    NASA Astrophysics Data System (ADS)

    Clark, D. S.; Hinkel, D. E.; Eder, D. C.; Jones, O. S.; Haan, S. W.; Hammel, B. A.; Marinak, M. M.; Milovich, J. L.; Robey, H. F.; Suter, L. J.; Town, R. P. J.

    2013-05-01

    More than two dozen inertial confinement fusion ignition experiments with cryogenic deuterium-tritium layers have now been performed on the National Ignition Facility (NIF) [G. H. Miller et al., Opt. Eng. 443, 2841 (2004)]. Each of these yields a wealth of data including neutron yield, neutron down-scatter fraction, burn-averaged ion temperature, x-ray image shape and size, primary and down-scattered neutron image shape and size, etc. Compared to 2-D radiation-hydrodynamics simulations modeling both the hohlraum and the capsule implosion, however, the measured capsule yield is usually lower by a factor of 5 to 10, and the ion temperature varies from simulations, while most other observables are well matched between experiment and simulation. In an effort to understand this discrepancy, we perform detailed post-shot simulations of a subset of NIF implosion experiments. Using two-dimensional HYDRA simulations [M. M. Marinak, et al., Phys. Plasmas 8, 2275 (2001).] of the capsule only, these simulations represent as accurately as possible the conditions of a given experiment, including the as-shot capsule metrology, capsule surface roughness, and ice layer defects as seeds for the growth of hydrodynamic instabilities. The radiation drive used in these capsule-only simulations can be tuned to reproduce quite well the measured implosion timing, kinematics, and low-mode asymmetry. In order to simulate the experiments as accurately as possible, a limited number of fully three-dimensional implosion simulations are also being performed. Despite detailed efforts to incorporate all of the effects known and believed to be important in determining implosion performance, substantial yield discrepancies remain between experiment and simulation. Some possible alternate scenarios and effects that could resolve this discrepancy are discussed.

  18. Status of the KATRIN experiment and prospects to search for keV-mass sterile neutrinos in tritium β-decay

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

    Mertens, Susanne

    In this contribution the current status and future perspectives of the Karlsruhe Tritium Neutrino (KATRIN) Experiment are presented. The prime goal of this single β-decay experiment is to probe the absolute neutrino mass scale with a sensitivity of 200 meV (90% CL). We discuss first results of the recent main spectrometer commissioning measurements, successfully verifying the spectrometer’s basic vacuum, transmission and background properties. We also discuss the prospects of making use of the KATRIN tritium source, to search for sterile neutrinos in the multi-keV mass range constituting a classical candidate for Warm Dark Matter. Due to the very high sourcemore » luminosity, a statistical sensitivity down to active-sterile mixing angles of sin² θ < 1 · 10⁻⁷ (90% CL) could be reached.« less

  19. Status of the KATRIN experiment and prospects to search for keV-mass sterile neutrinos in tritium β-decay

    DOE PAGES

    Mertens, Susanne

    2015-03-24

    In this contribution the current status and future perspectives of the Karlsruhe Tritium Neutrino (KATRIN) Experiment are presented. The prime goal of this single β-decay experiment is to probe the absolute neutrino mass scale with a sensitivity of 200 meV (90% CL). We discuss first results of the recent main spectrometer commissioning measurements, successfully verifying the spectrometer’s basic vacuum, transmission and background properties. We also discuss the prospects of making use of the KATRIN tritium source, to search for sterile neutrinos in the multi-keV mass range constituting a classical candidate for Warm Dark Matter. Due to the very high sourcemore » luminosity, a statistical sensitivity down to active-sterile mixing angles of sin² θ < 1 · 10⁻⁷ (90% CL) could be reached.« less

  20. The synthesis of tritium, carbon-14 and stable isotope labelled selective estrogen receptor degraders.

    PubMed

    Bragg, Ryan A; Bushby, Nick; Ericsson, Cecilia; Kingston, Lee P; Ji, Hailong; Elmore, Charles S

    2016-09-01

    As part of a Medicinal Chemistry program aimed at developing an orally bioavailable selective estrogen receptor degrader, a number of tritium, carbon-14, and stable isotope labelled (E)-3-[4-(2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl]prop-2-enoic acids were required. This paper discusses 5 synthetic approaches to this compound class. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Concentrations of tritium and strontium-90 in water from selected wells at the Idaho National Engineering Laboratory after purging one, two, and three borehole volumes

    USGS Publications Warehouse

    Bartholomay, R.C.

    1993-01-01

    Water from 11 wells completed in the Snake River Plain aquifer at the Idaho National Engineering Laboratory was sampled as part of the U.S. Geological Survey's quality assurance program to determine the effect of purging different borehole volumes on tritium and strontium-90 concentrations. Wells were selected for sampling on the basis of the length of time it took to purge a borehole volume of water. Samples were collected after purging one, two, and three borehole volumes. The U.S. Department of Energy's Radiological and Environmental Sciences Laboratory provided analytical services. Statistics were used to determine the reproducibility of analytical results. The comparison between tritium and strontium-90 concentrations after purging one and three borehole volumes and two and three borehole volumes showed that all but two sample pairs with defined numbers were in statistical agreement. Results indicate that concentrations of tritium and strontium-90 are not affected measurably by the number of borehole volumes purged.

  2. Concentrations of tritium and strontium-90 in water from selected wells at the Idaho National Engineering Laboratory after purging one, two, and three borehole volumes

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

    Bartholomay, R.C.

    1993-12-31

    Water from 11 wells completed in the Snake River Plain aquifer at the Idaho National Engineering Laboratory was sampled as Part of the US. Geological Survey`s quality assurance program to determine the effect of Purging different borehole volumes on tritium and strontium-90 concentrations. Wells were selected for sampling on the basis of the length of time it took to purge a borehole volume of water. Samples were collected after purging one, two, and three borehole volumes. The US Department of Energy`s Radiological and Environmental Sciences Laboratory provided analytical services. Statistics were used to determine the reproducibility of analytical results. Themore » comparison between tritium and strontium-90 concentrations after purging one and three borehole volumes and two and three borehole volumes showed that all but two sample pairs with defined numbers were in statistical agreement. Results indicate that concentrations of tritium and strontium-90 are not affected measurably by the number of borehole volumes purged.« less

  3. Incorporation of methamphetamine and amphetamine in human hair following controlled oral methamphetamine administration

    PubMed Central

    Polettini, Aldo; Cone, Edward J.; Gorelick, David A.; Huestis, Marilyn A.

    2012-01-01

    Background Although hair testing is well established for the assessment of past drug exposure, uncertainties persist about mechanisms of drug incorporation into hair and interpretation of results. The aim of this study was to administer methamphetamine (MAMP) under controlled conditions as a model drug to investigate drug incorporation into human hair. Material and Methods Seven volunteers with a history of stimulant use received 4×10 mg (low) doses of sustained release S-(+)-MAMP HCl within one week, with weekly head hair samples collected by shaving. 3 weeks later, 4 of them received 4×20 mg (high) doses. After extensive isopropanol/phosphate buffer washing of the hair, MAMP and its metabolite amphetamine (AMP) concentrations were determined in all weekly hair samples by LC-MS-MS in selected reaction monitoring mode with the undeca- and deca-deuterated drugs, respectively, as internal standards (LLOQ, 0.005 ng/mg). Results MAMP Tmax occurred from 1 to 2 weeks after both doses, with Cmax ranging from 0.6–3.5 ng/mg after the low and 1.2–5.3 ng/mg after the high MAMP doses. AMP Cmax in hair was 0.1–0.3 ng/mg and 0.2–0.5 ng/mg, respectively, for low and high doses. Highly dose–related concentrations within subjects, but large variability between subjects were observed. MAMP concentrations were above the 0.2 ng/mg cutoff for at least two weeks following administration of both low and high doses. The overall AMP/MAMP ratio ranged from 0.07 to 0.37 with a mean value of 0.15±0.07, and a median of 0.13. The percentage of MAMP and AMP removed with the washing procedure decreased with time after administration. A strong correlation was found between area under the curve of MAMP (r2=0.90, p=0.00) and AMP (r2=0.94, p=0.00) concentrations calculated for the 3-week period following administration and the total melanin concentration in hair. Significant correlations were observed also between Cmax and melanin. Conclusions This study demonstrated that despite large

  4. Evaluation of finger millet incorporated noodles for nutritive value and glycemic index.

    PubMed

    Shukla, Kamini; Srivastava, Sarita

    2014-03-01

    The present study was undertaken to develop finger millet incorporated noodles for diabetic patients. Finger millet variety VL-149 was taken. The finger millet flour and refined wheat flour (RWF) were evaluated for nutrient composition. The finger millet flour (FMF) was blended in various proportions (30 to 50%) in refined wheat flour and used for the preparation of noodles. Control consisted of RWF noodles. Sensory quality and nutrient composition of finger millet noodles was evaluated. The 30% finger millet incorporated noodles were selected best on the basis of sensory evaluation. Noodles in that proportion along with control were evaluated for glycemic response. Nutrient composition of noodles showed that 50% finger millet incorporated noodles contained highest amount of crude fat (1.15%), total ash (1.40%), crude fiber (1.28%), carbohydrate (78.54%), physiological energy (351.36 kcal), insoluble dietary fiber (5.45%), soluble dietary fiber (3.71%), iron (5.58%) and calcium (88.39%), respectively. However, control RWF noodles contained highest amount of starch (63.02%), amylose (8.72%) and amylopectin (54.29%). The glycemic index (GI) of 30% finger millet incorporated noodles (best selected by sensory evaluation) was observed significantly lower (45.13) than control noodles (62.59). It was found that finger millet flour incorporated noodles were found nutritious and showed hypoglycemic effect.

  5. Point defect reduction in MOCVD (Al)GaN by chemical potential control and a comprehensive model of C incorporation in GaN

    NASA Astrophysics Data System (ADS)

    Reddy, Pramod; Washiyama, Shun; Kaess, Felix; Kirste, Ronny; Mita, Seiji; Collazo, Ramon; Sitar, Zlatko

    2017-12-01

    A theoretical framework that provides a quantitative relationship between point defect formation energies and growth process parameters is presented. It enables systematic point defect reduction by chemical potential control in metalorganic chemical vapor deposition (MOCVD) of III-nitrides. Experimental corroboration is provided by a case study of C incorporation in GaN. The theoretical model is shown to be successful in providing quantitative predictions of CN defect incorporation in GaN as a function of growth parameters and provides valuable insights into boundary phases and other impurity chemical reactions. The metal supersaturation is found to be the primary factor in determining the chemical potential of III/N and consequently incorporation or formation of point defects which involves exchange of III or N atoms with the reservoir. The framework is general and may be extended to other defect systems in (Al)GaN. The utility of equilibrium formalism typically employed in density functional theory in predicting defect incorporation in non-equilibrium and high temperature MOCVD growth is confirmed. Furthermore, the proposed theoretical framework may be used to determine optimal growth conditions to achieve minimum compensation within any given constraints such as growth rate, crystal quality, and other practical system limitations.

  6. Estimating groundwater recharge in Hebei Plain, China under varying land use practices using tritium and bromide tracers

    NASA Astrophysics Data System (ADS)

    Wang, Bingguo; Jin, Menggui; Nimmo, John R.; Yang, Lei; Wang, Wenfeng

    2008-07-01

    SummaryTritium and bromide were used as applied tracers to determine groundwater recharge in Hebei Plain, North China, to evaluate the impacts of different soil types, land use, irrigation, and crop cultivation practice on recharge. Additional objectives were to evaluate temporal variability of recharge and the effect on results of the particular tracer used. Thirty-nine profiles at representative locations were chosen for investigation. Average recharge rates and recharge coefficient determined by tritium and bromide tracing for different sites were 0.00-1.05 mm/d and 0.0-42.5%, respectively. The results showed relative recharge rates for the following paired influences (items within each pair are listed with the influence producing greater recharge first): flood-irrigated cropland and non-irrigated non-cultivation land, flood irrigation (0.42-0.58 mm/d) and sprinkling irrigation (0.17-0.23 mm/d), no stalk mulch (0.56-0.80 mm/d) and stalk mulch (0.44-0.60 mm/d), vegetable (e.g. Chinese cabbage and garlic, 0.70 mm/d) and wheat-maize (0.38 mm/d), peanut (0.51 mm/d) and peach (0.43 mm/d). The results also showed greater recharge for the first year of tracer travel than for the second. Because total precipitation and irrigation were greater in the first year than in the second, this may reflect temporal variability of recharge. The method may not be applicable where the water table is shallow (less than 3 m). A comparison of the near-ideal tritium tracer with the more common but less ideal bromide showed that bromide moved approximately 23% faster than tritiated water, perhaps because of anion exclusion.

  7. Chlorofluorocarbon and tritium age determination of ground-water recharge in the Ryan Flat subbasin, Trans-Pecos Texas

    USGS Publications Warehouse

    Bartolino, J.R.

    1997-01-01

    A study was conducted to determine the relative influence of mountain-front infiltration in the Ryan Flat subbasin and to determine whether recent recharge (post-1940), which is of importance to water-use planning, has reached the Salt Basin aquifer, Trans-Pecos Texas. The alluvial and volcanic Salt Basin aquifer lies within a bolson, and the average depth to water in most of the subbasin is approximately 250 feet. Concentrations of the chlorofluorocarbons CFC-11, CFC-12, and CFC-113, as well as tritium, were measured in water from 10 wells in the study area. CFC-model recharge dates ranged from pre-1940 to the early 1970's. Ground water in five wells had CFC-model dates of pre-1940 or pre-1945. Ground water in two wells had dates of the mid- to late 1940's. Ground water from one well had a CFC-model recharge age of the early 1950's. Samples from the remaining two wells were most probably contaminated in some manner and are probably unreliable. CFC-model ages were calculated independently for the three chlorofluorocarbons, though the presence of volatile organic compounds affected agreement among them. Tritium activities in the nine wells for which tritium was analyzed indicated pre-1953 recharge and thus agreed approximately with the CFC-model dates. Ground water was analyzed for selected water-quality constituents. Water from all wells met U.S. Environmental Protection Agency national primary and secondary drinking water standards for all tested constituents except fluoride in samples from three wells. Silica concentrations in water from six wells exceeded a range considered typical in natural waters.

  8. Estimating groundwater recharge in Hebei Plain, China under varying land use practices using tritium and bromide tracers

    USGS Publications Warehouse

    Wang, B.; Jin, M.; Nimmo, J.R.; Yang, L.; Wang, W.

    2008-01-01

    Tritium and bromide were used as applied tracers to determine groundwater recharge in Hebei Plain, North China, to evaluate the impacts of different soil types, land use, irrigation, and crop cultivation practice on recharge. Additional objectives were to evaluate temporal variability of recharge and the effect on results of the particular tracer used. Thirty-nine profiles at representative locations were chosen for investigation. Average recharge rates and recharge coefficient determined by tritium and bromide tracing for different sites were 0.00-1.05 mm/d and 0.0-42.5%, respectively. The results showed relative recharge rates for the following paired influences (items within each pair are listed with the influence producing greater recharge first): flood-irrigated cropland and non-irrigated non-cultivation land, flood irrigation (0.42-0.58 mm/d) and sprinkling irrigation (0.17-0.23 mm/d), no stalk mulch (0.56-0.80 mm/d) and stalk mulch (0.44-0.60 mm/d), vegetable (e.g. Chinese cabbage and garlic, 0.70 mm/d) and wheat-maize (0.38 mm/d), peanut (0.51 mm/d) and peach (0.43 mm/d). The results also showed greater recharge for the first year of tracer travel than for the second. Because total precipitation and irrigation were greater in the first year than in the second, this may reflect temporal variability of recharge. The method may not be applicable where the water table is shallow (less than 3 m). A comparison of the near-ideal tritium tracer with the more common but less ideal bromide showed that bromide moved approximately 23% faster than tritiated water, perhaps because of anion exclusion. ?? 2008 Elsevier B.V.

  9. Sol-gel synthesis of lithium metatitanate as tritium breeding material under different sintering conditions

    NASA Astrophysics Data System (ADS)

    Lu, Wei; Wang, Jing; Pu, Wenjing; Li, Kaiping; Ma, Shubing; Wang, Weihua

    2018-04-01

    Lithium metatitanate (Li2TiO3) is a promising tritium breeding material candidate for solid blanket of D-T fusion reactors, due to its high mechanical strength, chemical stability, and tritium release rate. In this paper, Li2TiO3 powder with homogeneous crystal structure is synthesized by sol-gel method. The chemical reactions in gel thermal cracking and sintering process are studied by thermo gravimetric/differential scanning calorimetry (TG-DSC). The relationship between the sintering condition and the particle/grain size is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results show that below 673 K the gel precursor is completely decomposed and Li2TiO3 phase initially forms. The LiTiO2 by-product formed under the reductive atmosphere in muffle furnace, could be oxidized continually to Li2TiO3 at higher sintering temperature (≥1273 K) for longer sintering time (≥10 h). Both grain and particle sizes rely on a linear growth with the increase of sintering time at 1273 K. Over 1473 K, significant agglomerations exist among particles. The optimal sintering condition is selected as 1273 K for 10 h, for the purer Li2TiO3 phase (>99%), smaller grain and particle size.

  10. Long-term stability of dental adhesive incorporated by boron nitride nanotubes.

    PubMed

    Degrazia, Felipe Weidenbach; Leitune, Vicente Castelo Branco; Visioli, Fernanda; Samuel, Susana Maria Werner; Collares, Fabrício Mezzomo

    2018-03-01

    The aim of this study was to evaluate physicochemical properties, long-term microtensile bond strength and cytotoxicity of methacrylate-based adhesive containing boron nitride nanotubes (BNNTs) as fillers. A dental adhesive was formulated using BisGMA/HEMA, 66/33wt% (control). Inorganic BNNT fillers were incorporated into the adhesive at different concentrations (0.05, 0.075, 0.1 and 0.15wt%). Analyses of degree of conversion (DC), polymerization rate [Rp.(s -1 )], contact angle (CA) on dentin, after 24h and 6 months microtensile bond strength (μTBS-24h and 6 months) were assessed. Cytotoxicity was performed through viability of fibroblast cells (%) by sulforhodamine B (SRB) colorimetry. DC and max. polymerization rate increased (p<0.05) after incorporating 0.075 and 0.1wt% BNNT. The contact angle on dentin increased (p<0.05) after incorporating 0.15wt% BNNT. The μTBS-24h showed no changes (p>0.05) after incorporating up to 0.15wt% BNNT comparing to control. After 6 months, μTBS decreased (p<0.05) for control and 0.15wt% BNNT and BNNT groups up to 0.15wt% showed higher μTBS than control (p<0.05). No difference of fibroblast growth was found among adhesives (p>0.05) and up to 19% of cell viability was found comparing 0.05wt% BNNT to positive control group (100%). Incorporating boron nitride nanotubes up to 0.1wt% into dental adhesive increased the long-term stability to dentin without decreasing viability of fibroblast cell growth. Thus, the use of BNNTs as filler may decrease failure rate of current dentinal adhesives. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  11. Safety analysis report -- Packages LP-50 tritium package (Packaging of fissile and other radioactive materials)

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

    Gates, A.A.; McCarthy, P.G.; Edl, J.W.

    1975-05-01

    Elemental tritium is shipped at low pressure in a stainless steel container (LP-50) surrounded by an aluminum vessel and Celotex insulation at least 4 in. thick in a steel drum. Each package contains a large quantity (greater than a Type A quantity) of nonfissile material, as defined in AECM 0529. This report provides the details of the safety analysis performed for this type container.

  12. The use of tritium content as an indicator of the groundwater contamination by sanitary landfills leachates in the region of Belo Horizonte City, Brazil.

    PubMed

    Bandeira, J V; Mingote, R M; Baptista, M B; Oliveira, D M; Lima, F P

    2008-01-01

    Tritium content in the leachate of sanitary landfills, in concentrations well above those observed in global precipitation, can be used as a tracer for the evaluation of the contamination of groundwater in piezometers of the landfills and in neighbouring tubular wells. This possibility was first investigated in Brazil for sanitary landfills in the region of Belo Horizonte City. Tritium levels together with the content of metals present in water and the measurement of soil electrical conductivity, proved to be valuable for these studies and also as a tracer for hydrodynamic studies of the surface water in the Ressaca creek. IWA Publishing 2008.

  13. A simplified model for tritium permeation transient predictions when trapping is active*1

    NASA Astrophysics Data System (ADS)

    Longhurst, G. R.

    1994-09-01

    This report describes a simplified one-dimensional tritium permeation and retention model. The model makes use of the same physical mechanisms as more sophisticated, time-transient codes such as implantation, recombination, diffusion, trapping and thermal gradient effects. It takes advantage of a number of simplifications and approximations to solve the steady-state problem and then provides interpolating functions to make estimates of intermediate states based on the steady-state solution. Comparison calculations with the verified and validated TMAP4 transient code show good agreement.

  14. Controlled Defects of Fluorine-incorporated ZnO Nanorods for Photovoltaic Enhancement

    PubMed Central

    Lee, Hock Beng; Ginting, Riski Titian; Tan, Sin Tee; Tan, Chun Hui; Alshanableh, Abdelelah; Oleiwi, Hind Fadhil; Yap, Chi Chin; Jumali, Mohd Hafizuddin Hj.; Yahaya, Muhammad

    2016-01-01

    Anion passivation effect on metal-oxide nano-architecture offers a highly controllable platform for improving charge selectivity and extraction, with direct relevance to their implementation in hybrid solar cells. In current work, we demonstrated the incorporation of fluorine (F) as an anion dopant to address the defect-rich nature of ZnO nanorods (ZNR) and improve the feasibility of its role as electron acceptor. The detailed morphology evolution and defect engineering on ZNR were studied as a function of F-doping concentration (x). Specifically, the rod-shaped arrays of ZnO were transformed into taper-shaped arrays at high x. A hypsochromic shift was observed in optical energy band gap due to the Burstein-Moss effect. A substantial suppression on intrinsic defects in ZnO lattice directly epitomized the novel role of fluorine as an oxygen defect quencher. The results show that 10-FZNR/P3HT device exhibited two-fold higher power conversion efficiency than the pristine ZNR/P3HT device, primarily due to the reduced Schottky defects and charge transfer barrier. Essentially, the reported findings yielded insights on the functions of fluorine on (i) surface –OH passivation, (ii) oxygen vacancies (Vo) occupation and (iii) lattice oxygen substitution, thereby enhancing the photo-physical processes, carrier mobility and concentration of FZNR based device. PMID:27587295

  15. Genetic incorporation of recycled unnatural amino acids.

    PubMed

    Ko, Wooseok; Kim, Sanggil; Jo, Kyubong; Lee, Hyun Soo

    2016-02-01

    The genetic incorporation of unnatural amino acids (UAAs) into proteins has been a useful tool for protein engineering. However, most UAAs are expensive, and the method requires a high concentration of UAAs, which has been a drawback of the technology, especially for large-scale applications. To address this problem, a method to recycle cultured UAAs was developed. The method is based on recycling a culture medium containing the UAA, in which some of essential nutrients were resupplemented after each culture cycle, and induction of protein expression was controlled with glucose. Under optimal conditions, five UAAs were recycled for up to seven rounds of expression without a decrease in expression level, cell density, or incorporation fidelity. This method can generally be applied to other UAAs; therefore, it is useful for reducing the cost of UAAs for genetic incorporation and helpful for expanding the use of the technology to industrial applications.

  16. Improvements to sample processing and measurement to enable more widespread environmental application of tritium

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

    Moran, James; Alexander, Thomas; Aalseth, Craig

    2017-08-01

    Previous measurements have demonstrated the wealth of information that tritium (T) can provide on environmentally relevant processes. We present modifications to sample preparation approaches that enable T measurement by proportional counting on small sample sizes equivalent to 120 mg of water and demonstrate the accuracy of these methods on a suite of standardized water samples. This enhanced method should provide the analytical flexibility needed to address persistent knowledge gaps in our understanding of T behavior in the environment.

  17. Preparation of gelatin films incorporated with tea polyphenol nanoparticles for enhancing controlled-release antioxidant properties

    USDA-ARS?s Scientific Manuscript database

    Tea polyphenols (TP) were incorporated into edible gelatin films either alone or incorporated into nanoparticles in order to determine the physico-chemical properties of the film and the antioxidant properties of TP in a solid gelatin matrix. The TP containing nanoparticles were prepared by cross-li...

  18. Interlinked Test Results for Fusion Fuel Processing and Blanket Tritium Recovery Systems Using Cryogenic Molecular Sieve Bed

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

    Yamanishi, Toshihiko; Hayashi, Takumi; Kawamura, Yoshinori

    2005-07-15

    A simulated fuel processing (cryogenic distillation columns and a palladium diffuser) and CMSB (cryogenic molecular sieve bed) systems were linked together, and were operated. The validity of the CMSB was discussed through this experiment as an integrated system for the recovery of blanket tritium. A gas stream of hydrogen isotopes and He was supplied to the CMSB as the He sweep gas in blanket of a fusion reactor. After the breakthrough of tritium was observed, regeneration of the CMSB was carried out by evacuating and heating. The hydrogen isotopes were finally recovered by the diffuser. At first, only He gasmore » was sent by the evacuating. The hydrogen isotopes gas was then rapidly released by the heating. The system worked well against the above drastic change of conditions. The amount of hydrogen isotopes gas finally recovered by the diffuser was in good agreement with that adsorbed by the CMSB. The dynamic behaviors (breakthrough and regeneration) of the system were explained well by a set of basic codes.« less

  19. The evaluation of the average energy parameters for spectra of quasimonoenergetic neutrons produced in (p,n)-reactions on solid tritium targets

    NASA Astrophysics Data System (ADS)

    Sosnin, A. N.; Shorin, V. S.

    1989-10-01

    Fast neutron cross-section measurements using quasimonoenergetic (p,n) neutron sources require the determination of the average neutron spectrum parameters such as the mean energy < E> and the variance D. In this paper a simple model has been considered for determining the < E>- andD-values. The approach takes into account the actual layout of the solid tritium target and the irradiated sample. It is valid for targets with a thickness of less than 1 mg/cm 2. It has been shown that the first and the second tritium distribution function moments < x> and < x2> are connected by simple analytical expressions with average characteristics of the neutron yield measured above the (p,n) reaction threshold energy. Our results are compared with accurate calculations for Sc-T targets.

  20. Incorporation of capsaicin in silicone coatings for enhanced antifouling performance

    NASA Astrophysics Data System (ADS)

    Reddy Jaggari, Karunakar; Zhang Newby, Bi-Min

    2002-03-01

    Successful use of capsaicin as insect and animal repellant propelled us to use it as a possible antifouling agent. Its non-toxic, non-biocidal, non-leaching properties make it a viable alternative to organotin compounds. In order to optimize the anti-fouling performance of the coating, silicone, the most effective foul-release marine coating, was chosen as the carrier. We have incorporated capsaicin into silicone coating, by both bulk entrapment and surface immobilization. Contact angle measurements on capsaicin-incorporated silicone exhibited an increase in wettability, owing to the presence of capsaicin. FTIR study further confirmed the incorporation of capsaicin in silicone. Bacterial attachment studies were conducted using lake Erie water. While bacteria liberally inhabited the control coating, their presence on the capsaicin-incorporated coating was found to be minimal. These preliminary studies indicate that capsaicin incorporated silicone could be a viable environment friendly alternative to currently used antifouling coatings.

  1. Control of biofilm formation by poly-ethylene-co-vinyl acetate films incorporating nisin.

    PubMed

    Nostro, Antonia; Scaffaro, Roberto; Ginestra, Giovanna; D'Arrigo, Manuela; Botta, Luigi; Marino, Andreana; Bisignano, Giuseppe

    2010-06-01

    The aim of this study was to evaluate the effect of poly-ethylene-co-vinyl acetate (EVA) films incorporating different concentrations (0.1%, 0.5% and 1%) of nisin on the biofilm-forming ability of Listeria monocytogenes ATCC 7644, Staphylococcus aureus 815 and Staphylococcus epidermidis ATCC 35984. Nisin was incorporated into two grades of EVA (EVA14 and EVA28) in the melt during a common film-blowing operation. The efficacy of EVA/nisin films was evaluated by biofilm biomass measurements and Live/Dead staining in combination with fluorescence microscopy. In order to evaluate whether the nisin incorporation could modify the film surface properties, contact angle measurements and scanning electron microscopy were performed. The results revealed the efficacy of EVA14/nisin films in reducing biofilm formation on their surfaces with more evident effect for S. epidermidis than L. monocytogenes and S. aureus strains. In contrast, EVA28/nisin films showed unsatisfactory activity. Fluorescence microscopy confirmed poor biofilm formation on EVA14/nisin films, also characterised by the presence of dead cells. The data presented in this study offer new potential applications for developing strategies aimed to improve the effect of antimicrobial agents.

  2. Controlling Mechanical Properties of Cell-Laden Hydrogels by Covalent Incorporation of Graphene Oxide

    PubMed Central

    Cha, Chaenyung; Shin, Su Ryon; Gao, Xiguang; Annabi, Nasim; Dokmeci, Mehmet R.; Tang, Xiaowu (Shirley); Khademhosseini, Ali

    2013-01-01

    Graphene-based materials are useful reinforcing agents to modify the mechanical properties of hydrogels. Here, we present an approach to covalently incorporate graphene oxide (GO) into hydrogels via radical copolymerization to enhance the dispersion and conjugation of GO sheets within the hydrogels. GO is chemically modified to present surface-grafted methacrylate groups (MeGO). In comparison to GO, higher concentrations of MeGO can be stably dispersed in a pre-gel solution containing methacrylated gelatin (GelMA) without aggregation or significant increase in viscosity. In addition, the resulting MeGO-GelMA hydrogels demonstrate a significant increase in fracture strength with increasing MeGO concentration. Interestingly, the rigidity of the hydrogels is not significantly affected by the covalently incorporated GO. Therefore, our approach can be used to enhance the structural integrity and resistance to fracture of the hydrogels without inadvertently affecting their rigidity, which is known to affect the behavior of encapsulated cells. The biocompatibility of MeGO-GelMA hydrogels is confirmed by measuring the viability and proliferation of the encapsulated fibroblasts. Overall, this study highlights the advantage of covalently incorporating GO into a hydrogel system, and improves the quality of cell-laden hydrogels. PMID:24127350

  3. Key technologies for tritium storage bed development

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

    Yu, S.H.; Chang, M.H.; Kang, H.G.

    2015-03-15

    ITER Storage and Delivery System (SDS) is a complex system involving tens of storage beds. The most important SDS getter bed will be used for the absorption and desorption of hydrogen isotopes in accordance with the fusion fuel cycle scenario. In this paper the current status concerning research/development activities for the optimal approach to the final SDS design is introduced. A thermal analysis is performed and discussed on the aspect of heat losses considering whether the reflector and/or the feed-through is present or not. A thermal hydraulic simulation shows that the presence of 3 or 4 reflectors minimize the heatmore » loss. Another important point is to introduce the real-time gas analysis in the He{sup 3} collection system. In this study 2 independent strength methods based on gas chromatography and quadruple mass spectrometer for one and on a modified self-assaying quadruple mass spectrometer for the second are applied to separate the hydrogen isotopes in helium gas. Another issue is the possibility of using depleted uranium getter material for the storage of hydrogen isotopes, especially of tritium.« less

  4. Visuomotor control, eye movements, and steering: A unified approach for incorporating feedback, feedforward, and internal models.

    PubMed

    Lappi, Otto; Mole, Callum

    2018-06-11

    The authors present an approach to the coordination of eye movements and locomotion in naturalistic steering tasks. It is based on recent empirical research, in particular, on driver eye movements, that poses challenges for existing accounts of how we visually steer a course. They first analyze how the ideas of feedback and feedforward processes and internal models are treated in control theoretical steering models within vision science and engineering, which share an underlying architecture but have historically developed in very separate ways. The authors then show how these traditions can be naturally (re)integrated with each other and with contemporary neuroscience, to better understand the skill and gaze strategies involved. They then propose a conceptual model that (a) gives a unified account to the coordination of gaze and steering control, (b) incorporates higher-level path planning, and (c) draws on the literature on paired forward and inverse models in predictive control. Although each of these (a-c) has been considered before (also in the context of driving), integrating them into a single framework and the authors' multiple waypoint identification hypothesis within that framework are novel. The proposed hypothesis is relevant to all forms of visually guided locomotion. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  5. In-reactor performance of LWR-type tritium target rods

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

    Lanning, D.D.; Paxton, M.M.; Crumbaugh, L.

    Pacific Northwest Laboratory has conducted several 1-yr irradiation tests of light water reactor-type tritium target rods. These tests have been sponsored by the U.S. Department of Energy's Office of New Production Reactors. The first test, designated water capsule-1 (WC-1), was conducted in the Advanced Test Reactor (ATR) at the Idaho National Engineering Laboratory from November 1989 to December 1990. The test vehicle contained a single 4-ft target rod within a pressurized water capsule. The capsule maintained the rod at pressurized water reactor (PWR)-type water temperature and pressure conditions. Posttest nondestructive examinations of the WC-1 rod involved visual examinations, dimensional checks,more » gamma scanning, and neutron radiography. The results indicate that the rod maintained the integrity of its pressure seal and was otherwise unaltered both mechanically and dimensionally by its irradiation and posttest handling.« less

  6. Use of antimicrobial films and edible coatings incorporating chemical and biological preservatives to control growth of Listeria monocytogenes on cold smoked salmon.

    PubMed

    Neetoo, Hudaa; Mahomoodally, Fawzi

    2014-01-01

    The relatively high incidence of Listeria monocytogenes in cold smoked salmon (CSS) is of concern as it is a refrigerated processed food of extended durability (REPFED). The objectives of this study were to compare and optimize the antimicrobial effectiveness of films and coatings incorporating nisin (Nis) and sodium lactate (SL), sodium diacetate (SD), potassium sorbate (PS), and/or sodium benzoate (SB) in binary or ternary combinations on CSS. Surface treatments incorporating Nis (25000 IU/mL) in combination with PS (0.3%) and SB (0.1%) had the highest inhibitory activity, reducing the population of L. monocytogenes by a maximum of 3.3 log CFU/cm(2) (films) and 2.9 log CFU/cm(2) (coatings) relative to control samples after 10 days of storage at 21°C. During refrigerated storage, coatings were more effective in inhibiting growth of L. monocytogenes than their film counterparts. Cellulose-based coatings incorporating Nis, PS, and SB reduced the population of L. monocytogenes, and anaerobic and aerobic spoilage flora by a maximum of 4.2, 4.8, and 4.9 log CFU/cm(2), respectively, after 4 weeks of refrigerated storage. This study highlights the effectiveness of cellulose-based edible coatings incorporating generally regarded as safe (GRAS) natural and chemical antimicrobials to inhibit the development of L. monocytogenes and spoilage microflora thus enhancing the safety and quality of CSS.

  7. Use of Antimicrobial Films and Edible Coatings Incorporating Chemical and Biological Preservatives to Control Growth of Listeria monocytogenes on Cold Smoked Salmon

    PubMed Central

    Mahomoodally, Fawzi

    2014-01-01

    The relatively high incidence of Listeria monocytogenes in cold smoked salmon (CSS) is of concern as it is a refrigerated processed food of extended durability (REPFED). The objectives of this study were to compare and optimize the antimicrobial effectiveness of films and coatings incorporating nisin (Nis) and sodium lactate (SL), sodium diacetate (SD), potassium sorbate (PS), and/or sodium benzoate (SB) in binary or ternary combinations on CSS. Surface treatments incorporating Nis (25000 IU/mL) in combination with PS (0.3%) and SB (0.1%) had the highest inhibitory activity, reducing the population of L. monocytogenes by a maximum of 3.3 log CFU/cm2 (films) and 2.9 log CFU/cm2 (coatings) relative to control samples after 10 days of storage at 21°C. During refrigerated storage, coatings were more effective in inhibiting growth of L. monocytogenes than their film counterparts. Cellulose-based coatings incorporating Nis, PS, and SB reduced the population of L. monocytogenes, and anaerobic and aerobic spoilage flora by a maximum of 4.2, 4.8, and 4.9 log CFU/cm2, respectively, after 4 weeks of refrigerated storage. This study highlights the effectiveness of cellulose-based edible coatings incorporating generally regarded as safe (GRAS) natural and chemical antimicrobials to inhibit the development of L. monocytogenes and spoilage microflora thus enhancing the safety and quality of CSS. PMID:25089272

  8. Salinity controls on Na incorporation in Red Sea planktonic foraminifera

    NASA Astrophysics Data System (ADS)

    Mezger, E. M.; de Nooijer, L. J.; Boer, W.; Brummer, G. J. A.; Reichart, G. J.

    2016-12-01

    Whereas several well-established proxies are available for reconstructing past temperatures, salinity remains challenging to assess. Reconstructions based on the combination of (in)organic temperature proxies and foraminiferal stable oxygen isotopes result in relatively large uncertainties, which may be reduced by application of a direct salinity proxy. Cultured benthic and planktonic foraminifera showed that Na incorporation in foraminiferal shell calcite provides a potential independent proxy for salinity. Here we present the first field calibration of such a potential proxy. Living planktonic foraminiferal specimens from the Red Sea surface waters were collected and analyzed for their Na/Ca content using laser ablation quadrupole inductively coupled plasma mass spectrometry. Using the Red Sea as a natural laboratory, the calibration covers a broad range of salinities over a steep gradient within the same water mass. For both Globigerinoides ruber and Globigerinoides sacculifer calcite Na/Ca increases with salinity, albeit with a relatively large intraspecimen and interspecimen variability. The field-based calibration is similar for both species from a salinity of 36.8 up to 39.6, while values for G. sacculifer deviate from this trend in the northernmost transect. It is hypothesized that the foraminifera in the northernmost part of the Red Sea are (partly) expatriated and hence should be excluded from the Na/Ca-salinity calibration. Incorporation of Na in foraminiferal calcite therefore provides a potential proxy for salinity, although species-specific calibrations are still required and more research on the effect of temperature is needed.

  9. An integrative model of the cardiac ventricular myocyte incorporating local control of Ca2+ release.

    PubMed Central

    Greenstein, Joseph L; Winslow, Raimond L

    2002-01-01

    The local control theory of excitation-contraction (EC) coupling in cardiac muscle asserts that L-type Ca(2+) current tightly controls Ca(2+) release from the sarcoplasmic reticulum (SR) via local interaction of closely apposed L-type Ca(2+) channels (LCCs) and ryanodine receptors (RyRs). These local interactions give rise to smoothly graded Ca(2+)-induced Ca(2+) release (CICR), which exhibits high gain. In this study we present a biophysically detailed model of the normal canine ventricular myocyte that conforms to local control theory. The model formulation incorporates details of microscopic EC coupling properties in the form of Ca(2+) release units (CaRUs) in which individual sarcolemmal LCCs interact in a stochastic manner with nearby RyRs in localized regions where junctional SR membrane and transverse-tubular membrane are in close proximity. The CaRUs are embedded within and interact with the global systems of the myocyte describing ionic and membrane pump/exchanger currents, SR Ca(2+) uptake, and time-varying cytosolic ion concentrations to form a model of the cardiac action potential (AP). The model can reproduce both the detailed properties of EC coupling, such as variable gain and graded SR Ca(2+) release, and whole-cell phenomena, such as modulation of AP duration by SR Ca(2+) release. Simulations indicate that the local control paradigm predicts stable APs when the L-type Ca(2+) current is adjusted in accord with the balance between voltage- and Ca(2+)-dependent inactivation processes as measured experimentally, a scenario where common pool models become unstable. The local control myocyte model provides a means for studying the interrelationship between microscopic and macroscopic behaviors in a manner that would not be possible in experiments. PMID:12496068

  10. Controlling mechanical properties of cell-laden hydrogels by covalent incorporation of graphene oxide.

    PubMed

    Cha, Chaenyung; Shin, Su Ryon; Gao, Xiguang; Annabi, Nasim; Dokmeci, Mehmet R; Tang, Xiaowu Shirley; Khademhosseini, Ali

    2014-02-12

    Graphene-based materials are useful reinforcing agents to modify the mechanical properties of hydrogels. Here, an approach is presented to covalently incorporate graphene oxide (GO) into hydrogels via radical copolymerization to enhance the dispersion and conjugation of GO sheets within the hydrogels. GO is chemically modified to present surface-grafted methacrylate groups (MeGO). In comparison to GO, higher concentrations of MeGO can be stably dispersed in a pre-gel solution containing methacrylated gelatin (GelMA) without aggregation or significant increase in viscosity. In addition, the resulting MeGO-GelMA hydrogels demonstrate a significant increase in fracture strength with increasing MeGO concentration. Interestingly, the rigidity of the hydrogels is not significantly affected by the covalently incorporated GO. Therefore, this approach can be used to enhance the structural integrity and resistance to fracture of the hydrogels without inadvertently affecting their rigidity, which is known to affect the behavior of encapsulated cells. The biocompatibility of MeGO-GelMA hydrogels is confirmed by measuring the viability and proliferation of the encapsulated fibroblasts. Overall, this study highlights the advantage of covalently incorporating GO into a hydrogel system, and improves the quality of cell-laden hydrogels. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Static Performance of a Fixed-Geometry Exhaust Nozzle Incorporating Porous Cavities for Shock-Boundary Layer Interaction Control

    NASA Technical Reports Server (NTRS)

    Asbury, Scott C.; Hunter, Craig A.

    1999-01-01

    An investigation was conducted in the model preparation area of the Langley 16-Foot Transonic Tunnel to determine the internal performance of a fixed-geometry exhaust nozzle incorporating porous cavities for shock-boundary layer interaction control. Testing was conducted at static conditions using a sub-scale nozzle model with one baseline and 27 porous configurations. For the porous configurations, the effects of percent open porosity, hole diameter, and cavity depth were determined. All tests were conducted with no external flow at nozzle pressure ratios from 1.25 to approximately 9.50. Results indicate that baseline nozzle performance was dominated by unstable, shock-induced, boundary-layer separation at over-expanded conditions. Porous configurations were capable of controlling off-design separation in the nozzle by either alleviating separation or encouraging stable separation of the exhaust flow. The ability of the porous nozzle concept to alternately alleviate separation or encourage stable separation of exhaust flow through shock-boundary layer interaction control offers tremendous off-design performance benefits for fixed-geometry nozzle installations. In addition, the ability to encourage separation on one divergent flap while alleviating it on the other makes it possible to generate thrust vectoring using a fixed-geometry nozzle.

  12. Isolation of a spontaneous CHO amino acid transport mutant by a combination of tritium suicide and replica plating

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

    Dantzig, A.H.; Slayman, C.W.; Adelberg, E.A.

    A spontaneous transport mutant of Chinese hamster ovary cells, CHY-1, was isolated by a combination of (/sup 3/H)proline suicide and replica plating. The mutant took up less tritium than the parent, resulting in a lower killing rate during storage. Transport by four separate amino acid transport systems (A, ASC, L, Ly+) was examined. The CHY-1 mutant exhibited normal uptake via the ASC, L, and Ly+ systems. By contrast, uptake of the most specific substrate of the A system, 2-(methylamino)-isobutyric acid, was significantly reduced at low, but not high, concentrations, due to a 3.5-fold increase in Km and a 1.5-fold increasemore » in Vmax. Taken together, these data suggest that the CHY-1 mutation may be in the structural gene coding for the A transport protein. The tritium suicide procedure is discussed, and general equations are derived to predict the maximum storage time for the survival of one mutant cell and the optimum size of the cell population for maximum mutant enrichment.« less

  13. Tritium concentrations in the active Pu'u O'o crater, Kilauea volcano, Hawaii: implications for cold fusion in the Earth's interior

    NASA Astrophysics Data System (ADS)

    Quick, J. E.; Hinkley, T. K.; Reimer, G. M.; Hedge, C. E.

    1991-11-01

    The assertion that deuterium-deuterium fusion may occur at low temperature suggests a potential new source of geothermal heat. If a cold-fusion-like process occurs within the Earth, then a test for its existence would be a search for anomalous tritium in volcanic emissions. The Pu'u O'o crater is the first point at which large amounts of water are degassed from the magma that feeds the Kilauea system. The magma is probably not contaminated by meteoric-source ground water prior to degassing at Pu'u O'o, although mixing of meteoric and magmatic H 2O occurs within the crater. Tritium contents of samples from within the crater are lower than in samples taken simultaneously from the nearby upwind crater rim. These results provide no evidence in support of a cold-fusion-like process in the Earth's interior.

  14. Tritium concentrations in the active Pu'u O'o crater, Kilauea volcano, Hawaii: implications for cold fusion in the Earth's interior

    USGS Publications Warehouse

    Quick, J.E.; Hinkley, T.K.; Reimer, G.M.; Hedge, C.E.

    1991-01-01

    The assertion that deuterium-deuterium fusion may occur at low temperature suggests a potential new source of geothermal heat. If a cold-fusion-like process occurs within the Earth, then a test for its existence would be a search for anomalous tritium in volcanic emissions. The Pu'u O'o crater is the first point at which large amounts of water are degassed from the magma that feeds the Kilauea system. The magma is probably not contaminated by meteoric-source ground water prior to degassing at Pu'u O'o, although mixing of meteoric and magmatic H2O occurs within the crater. Tritium contents of samples from within the crater are lower than in samples taken simultaneously from the nearby upwind crater rim. These results provide no evidence in support of a cold-fusion-like process in the Earth's interior. ?? 1991.

  15. Properties and antioxidant activity of fish skin gelatin film incorporated with citrus essential oils.

    PubMed

    Tongnuanchan, Phakawat; Benjakul, Soottawat; Prodpran, Thummanoon

    2012-10-01

    Properties of protein-based film from fish skin gelatin incorporated with different citrus essential oils, including bergamot, kaffir lime, lemon and lime (50% based on protein) in the presence of 20% and 30% glycerol were investigated. Films containing 20% glycerol had higher tensile strength (TS) but lower elongation at break (EAB), compared with those prepared with 30% glycerol, regardless of essential oils incorporated (p<0.05). Films incorporated with essential oils, especially from lime, at both glycerol levels showed the lower TS but higher EAB than the control films (without incorporated essential oil) (p<0.05). Water vapour permeability (WVP) of films containing essential oils was lower than that of control films for both glycerol levels (p<0.05). Films with essential oils had varying ΔE(*) (total colour difference), where the highest value was observed in that added with bergamot essential oil (p<0.05). Higher glycerol content increased EAB and WVP but decreased TS of films. Fourier transforms infrared (FTIR) spectra indicated that films added with essential oils exhibited higher hydrophobicity with higher amplitude at wavenumber of 2874-2926 cm(-1) and 1731-1742 cm(-1) than control film. Film incorporated with essential oils exhibited slightly lower thermal degradation resistance, compared to the control film. Varying effect of essential oil on thermal degradation temperature and weight loss was noticeable, but all films prepared using 20% glycerol had higher thermal degradation temperature with lower weight loss, compared with those containing 30% glycerol. Films added with all types of essential oils had rough cross-section, compared with control films, irrespective of glycerol levels. However, smooth surface was observed in all film samples. Film incorporated with lemon essential oil showed the highest ABTS radical scavenging activity and ferric reducing antioxidant power (FRAP) (p<0.05), while the other films had lower activity. Thus, the

  16. Synthesis of nickel-incorporated larch-based carbon membranes with controllable porous structure for gas separation

    NASA Astrophysics Data System (ADS)

    Zhao, Xin; Li, Wei; Huang, Zhanhua; Liu, Shouxin

    2015-11-01

    Ni-incorporated larch-based carbon membranes have been synthesized by introducing the Ni(NO3)2 into the liquefied larch using liquefied larch sawdust as precursors and F127 as the soft template. The porous structure can be tailored by the amount of Ni(NO3)2, and the Ni and NiO nanoparticles with a size of 10 nm incorporated in the carbon frameworks. The increase in Ni(NO3)2 content can lead to the formation of disordered porous structure and shrinkage of carbon frameworks. The Ni-incorporated carbon membranes with largest pores possess highest gas permeation for N2, CO2, and O2 of 37.5, 19.8, and 55.5 m3 cm/m2 h kPa, which is larger than that of the pure carbon membranes, respectively. However, the poor ordered porous structure caused by adding large amount of Ni(NO3)2 can reduce the gas separation performance, which is attributed to the weaken of the molecular sieve function. The results indicate that the incorporation of few nanoparticles into larch-based carbon membranes can improve molecular sieve function.

  17. Incorporation of nanoparticles into polymersomes: size and concentration effects.

    PubMed

    Jaskiewicz, Karmena; Larsen, Antje; Schaeffel, David; Koynov, Kaloian; Lieberwirth, Ingo; Fytas, George; Landfester, Katharina; Kroeger, Anja

    2012-08-28

    Because of the rapidly growing field of nanoparticles in therapeutic applications, understanding and controlling the interaction between nanoparticles and membranes is of great importance. While a membrane is exposed to nanoparticles its behavior is mediated by both their biological and physical properties. Constant interplay of these biological and physicochemical factors makes selective studies of nanoparticles uptake demanding. Artificial model membranes can serve as a platform to investigate physical parameters of the process in the absence of any biofunctional molecules and/or supplementary energy. Here we report on photon- and fluorescence-correlation spectroscopic studies of the uptake of nanosized SiO(2) nanoparticles by poly(dimethylsiloxane)-block-poly(2-methyloxazoline) vesicles allowing species selectivity. Analogous to the cell membrane, polymeric membrane incorporates particles using membrane fission and particles wrapping as suggested by cryo-TEM imaging. It is revealed that the incorporation process can be controlled to a significant extent by changing nanoparticles size and concentration. Conditions for nanoparticle uptake and controlled filling of polymersomes are presented.

  18. A geochemical and hydrological investigation of groundwater recharge in the Roswell basin of New Mexico: summary of results and updated listing of tritium determinations

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

    Gross, G.W.; Hoy, R.N.

    Different approaches were used to study recharge and flow patterns in the Roswell, New Mexico, artesian basin. Isotope determination for tritium, deuterium, and oxygen-18 were made as a function of time and space. Observation well levels, springflow, and precipitation were analyzed by stochastic/numerical approaches. Also, a hydrogeologic survey was made of representative springs in the recharge zone on the basin western flank. An updated listing of tritium activity in precipitation, springs, surface runoff, and subsurface water from over 120 sampling sites in the basin covers 117 pages of the report. Substantial deep leakage contributions from the basin western flank mustmore » be included to account for the basin groundwater budget.« less

  19. Incorporating injured employee outcomes into physical and occupational therapists' practice: a controlled trial of the Worker-Based Outcomes Assessment System.

    PubMed

    Ross, Robert H; Callas, Peter W; Sargent, Jesse Q; Amick, Benjamin C; Rooney, Ted

    2006-12-01

    Work related musculoskeletal disorders (WRMSDs) remain costly. The Worker-Based Outcomes Assessment System (WBOAS) is an injury treatment improvement tool. Its purpose is to increase treatment effectiveness and decrease the cost of care delivered in Occupational Health Service clinics. The study used a non-randomized (parallel cohort) control trial design to test the effects on injured employee outcomes of augmenting the standard care delivered by physical and occupational therapists (PT/OTs) with the WBOAS. The WBOAS works by putting patient-reported functional health status, pain symptom, and work role performance outcomes data into the hands of PT/OTs and their patients. Test clinic therapists were trained to incorporate WBOAS trends data into standard practice. Control clinic therapists delivered standard care alone. WBOAS-augmented PT/OT care did improve (p< or =.05) physical functioning and new injury/re-injury avoidance and, on these same dimensions, cost-adjusted outcome. It did not improve (p>.05) mental health or pain symptoms or return-to-work or stay-at-work success nor, on these same dimensions, cost-adjusted outcome. Training PT/OTs to incorporate patient-reported health status, pain symptom, and work role performance outcomes trends data into standard practice does appear to improve treatment effectiveness and cost on some (e.g. physical functioning) but not other (e.g. mental health, pain symptoms) outcomes.

  20. A comparison of the hot atom chemistry of muonium, tritium and positronium in gases

    NASA Astrophysics Data System (ADS)

    Fleming, Donald G.

    Energetic positive muons thermalizing in gases are observed in either diamagnetic environments, with relative fraction ƒ D, or as the polarized muonium atom ( Mu = μ+e-), with fraction ƒ Mu. In molecular gases, the fraction ƒ D is found to vary from ˜0.10 in NH 3 to ˜0.55 in CCl 4 at pressures near 1 atm (300K). The diamagnetic fraction (yield) is interpreted as due to hot atom reactions (Mu ∗) in complete analogy with past studies in hot tritium (T ∗) chemistry. Hot tritium yields are generally seen to be considerably larger than the muonium ones, although there are marked exceptions to this, notably in the chloroalkanes. In the (unmoderated) normal alkanes, the ratio of T ∗/Mu ∗ reactivity is about 3.5. An interpretation of this ratio within the Wolfgang-Estrup formalism gives about 6 for the corresponding ratio of reactivity integrals I(T ∗)/I(Mu ∗). The fractions of muonium seen in gases are compared with those found for positronium: there seems to be little, if any, evidence for hot positronium reactions in gases. The amount of muonium found in the gas phase is compared also with that in condensed phases: the large differences seen are indicative of radically different mechanisms, indicating the importance of either spur processes or the role played by many-body effects on the distribution of muon polarization in condensed media (or both).