The Experts below are selected from a list of 138 Experts worldwide ranked by ideXlab platform
H. W. Xiang - One of the best experts on this subject based on the ideXlab platform.
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Vapor Pressure and Critical Point of Tritium Oxide
Journal of Physical and Chemical Reference Data, 2003Co-Authors: H. W. XiangAbstract:A simple general corresponding-states principle has been developed to represent the vapor pressure of Tritium Oxide from its triple point to its critical point, to describe the available experimental data, and to extrapolate beyond their range. This work takes advantage of the adoptions of the ITS-90 temperature scale and of the new critical parameters obtained from the extended corresponding-states principle. The vapor pressure data are described within their scatter in the entire temperature range. Comparisons with the available experimental data show that the extended corresponding-states principle for vapor pressure can calculate values with good accuracy. The substance-dependent characteristic parameters are given, such as critical temperature, critical density, critical pressure, and acentric factor. The values of the pressures, along with their first and second derivatives, as a function of temperature over the entire region from the triple point to the critical point are tabulated and recommended for scientific and practical uses.
Bernd Kahn - One of the best experts on this subject based on the ideXlab platform.
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isotopic exchange and vapor pressure isotope effect in Tritium Oxide adsorption on silica gel
Journal of Physical Chemistry B, 1998Co-Authors: Robert Rosson, Richard Jakiel, Bernd KahnAbstract:Consistently lower Tritium concentrations found in water distilled from silica gel than in the water vapor that had been adsorbed from air stimulated this study of isotopic exchange and the vapor p...
David M. Hamby - One of the best experts on this subject based on the ideXlab platform.
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Uncertainty of the Tritium dose conversion factor.
Health physics, 1999Co-Authors: David M. HambyAbstract:Environmental releases of Tritium Oxide at a number of Department of Energy nuclear weapons facilities contribute to a significant portion of environmental dose. Several conversion factors are utilized in the estimation of human impact from these releases, e.g., dispersion coefficients, consumption rates, uptake factors, transport factors, dose conversion factors, and risk coefficients. A probabilistic determination of the Tritium dose conversion factor was generated in this work to assess the uncertainty of the internal dosimetry required to estimate dose equivalent given an intake of Tritium Oxide. The Tritium dose conversion factor was found to vary by a factor of about 15 with a median value of 2.2 x 10(-11) Sv Bq(-1) when considering orthovoltage x rays as the standard for estimating the relative biological effectiveness of Tritium. The median dose conversion factor increases by about 50%; however, when gamma radiation is considered as the standard. The current deterministic estimate of the Tritium dose conversion factor published by the DOE and the EPA is 1.7 x 10(-11) Sv Bq(-1), 25-50% lower than the median probabilistic values. The Tritium Oxide dose conversion factor model was found to be most sensitive to biological half-life and quality factor and is highly dependent on the standardizing radiation for RBE assessments.
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Predicted versus measured Tritium Oxide concentrations at the Savannah River Site.
Health physics, 1997Co-Authors: A.a. Simpkins, David M. HambyAbstract:Measured Tritium Oxide concentrations in air at various offsite locations are compared with concentrations predicted by three computer codes that are utilized at the Savannah River Site to estimate doses to maximally exposed offsite individuals. Annual average concentrations calculated by the computer models were compared with measured average concentrations taken from monitoring data collected over the last 10 y. The computer programs used for the comparison are AXAIRQ, MAXIGASP, and CAP88. The 10-y averaged ratios of predicted-to-measured Tritium Oxide air concentrations using AXAIRQ, MAXIGASP, and CAP88 are 1.89-0.56, 1.70{+-}0.48, and 1.40{+-}0.39, respectively. The difference in ratios is primarily due to different wind speed averages used within each of the models. These results show exceptional agreement, considering Gaussian plume models typically over predict annual average air concentrations by a factor of two to four. 31 refs., 5 figs., 4 tabs.
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The vegetation-to-air concentration ratio in a specific activity atmospheric Tritium model.
Health physics, 1994Co-Authors: David M. Hamby, L.r. BauerAbstract:Specific activity models are frequently used to estimate the concentration of Tritium Oxide in vegetation. In such models, a single value represents the ratio (R) of the specific activity of Tritium Oxide in vegetation to the specific activity of atmospheric Tritium Oxide. Federal agencies such as the Nuclear Regulatory Commission and the Environmental Protection Agency have not established a consensus default for R. Literature on this topic suggests that a site-specific distribution of R should be developed when feasible. In this study, a distribution of R is established for the Savannah River Site. Environmental Tritium concentrations in air and vegetation measured on and around the Savannah River Site over a 9-y period form the basis for the analysis. For dose assessments of chronic atmospheric Tritium releases at the Savannah River Site, R is best parameterized by a normal distribution with a mean of 0.54 and one standard deviation of 0.10. The Nuclear Regulatory Commission default for R is approximately equal to the Savannah River Site site-specific estimate. Based on the results, the default value for R recognized by the Environmental Protection Agency overestimates Tritium concentrations in vegetation and, therefore, doses from foodstuff consumption pathways at humid sites. For the Savannah River Site, the magnitude of the error is on the order of a factor of 2. This consideration may be important if an estimated dose approaches an as-low-as-reasonably-achievable or regulatory threshold. Conversely, without the benefit of site-specific data, ingestion doses may be underestimated in regions with dry climates.
D. L. Dunn - One of the best experts on this subject based on the ideXlab platform.
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Effluent Treatment Facility Tritium emissions monitoring
Fusion Science and Technology, 1992Co-Authors: D. L. DunnAbstract:An Environmental Protection Agency (EPA) approved sampling and analysis protocol was developed and executed to verify atmospheric emissions compliance for the new Savannah River Site (SRS) F/H area Effluent Treatment Facility. Sampling equipment was fabricated, installed, and tested at stack monitoring points for filtrable particulate radionuclides, radioactive iodine, and Tritium. The only detectable anthropogenic radionuclides released from Effluent Treatment Facility stacks during monitoring were iodine-129 and Tritium Oxide. This paper only examines the collection and analysis of Tritium Oxide.
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Effluent Treatment Facility Tritium emissions monitoring
Fusion Science and Technology, 1992Co-Authors: D. L. DunnAbstract:An Environmental Protection Agency (EPA) approved sampling and analysis protocol was developed and executed to verify atmospheric emissions compliance for the new Savannah River Site (SRS) F/H area Effluent Treatment Facility. Sampling equipment was fabricated, installed, and tested at stack monitoring points for filtrable particulate radionuclides, radioactive iodine, and Tritium. The only detectable anthropogenic radionuclides released from Effluent Treatment Facility stacks during monitoring were iodine-129 and Tritium Oxide. This paper only examines the collection and analysis of Tritium Oxide.
A.a. Simpkins - One of the best experts on this subject based on the ideXlab platform.
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Determination of optimum time interval of meteorological data used with atmospheric dose modeling at SRS
Health physics, 2000Co-Authors: A.a. Simpkins, Matthew J. Parker, Allen H. WeberAbstract:Measured Tritium Oxide concentrations in air were compared with calculated values using routine release Gaussian plume models for different time intervals of meteorological data. These comparisons determined an optimum time interval of meteorological data used with atmospheric dose models at the Savannah River Site (SRS). Meteorological data of varying time intervals (1 y to 10 y) were used for the comparison. Insignificant differences are seen in using a 1-y database as opposed to a 5-y database. Use of a 10-y database results in slightly higher or more conservative estimates. For meteorological databases of length 1 y to 5 y the mean ratio of predicted to measured Tritium Oxide concentrations is approximately 1.25 whereas for the 10-y database the ratio is closer to 1.35. Currently at the SRS a meteorological database of five year's duration is used for all dose models. This study suggests no substantially improved accuracy using shorter or longer time intervals.
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Predicted versus measured Tritium Oxide concentrations at the Savannah River Site.
Health physics, 1997Co-Authors: A.a. Simpkins, David M. HambyAbstract:Measured Tritium Oxide concentrations in air at various offsite locations are compared with concentrations predicted by three computer codes that are utilized at the Savannah River Site to estimate doses to maximally exposed offsite individuals. Annual average concentrations calculated by the computer models were compared with measured average concentrations taken from monitoring data collected over the last 10 y. The computer programs used for the comparison are AXAIRQ, MAXIGASP, and CAP88. The 10-y averaged ratios of predicted-to-measured Tritium Oxide air concentrations using AXAIRQ, MAXIGASP, and CAP88 are 1.89-0.56, 1.70{+-}0.48, and 1.40{+-}0.39, respectively. The difference in ratios is primarily due to different wind speed averages used within each of the models. These results show exceptional agreement, considering Gaussian plume models typically over predict annual average air concentrations by a factor of two to four. 31 refs., 5 figs., 4 tabs.
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Predicted versus measured Tritium Oxide concentrations at SRS
1995Co-Authors: A.a. SimpkinsAbstract:Measured Tritium Oxide concentrations at various offsite locations are compared with concentrations predicted by three computer codes that are utilized at SRS to predict doses to the maximally exposed offsite individuals. Annual average concentrations predicted by the computer programs were compared with measured average concentrations taken form data contained in the last ten years of SRS Environmental Reports. The computer programs used for the comparison are ACAIRQ, CAP88, and MAXIGASP.
