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A statistical evaluation of the radionuclide inventory in the 222-S Laboratory and a comparison with the current inventory estimates

Description: Department of Energy contractors responsible for the safe operation of non-reactor nuclear facilities need to establish maximum inventory limits on both radioactive and hazardous materials stored, used, or processed at their facilities. These contractors need to ensure that established maximum limits are not exceeded. This necessity is derived from the requirement to demonstrate that a non-reactor facility can by safely operated during normal and abnormal conditions. The 222-S Laboratory has established that a maximum of 800 core equivalent samples (CES)may be stored at the Laboratory. Using the CES definition one can determine the maximum allowed curies pre radionuclide permitted. These estimates were made using a variation on a statistical technique called smoothed-bootstrapping. Smoothed- bootstrapping is a method analogous to Monte Carlo simulation using a smoothed empirical probability distribution. This report discusses the application of the smoothed bootstrap technique to predicting the curie inventory retained in the numerous waste tank samples for the radionuclides of concern and the uncertainty associated with such a prediction.
Date: September 1, 1996
Creator: Painter, C.L.; Daly, D.S. & Welsh, T.L.
Partner: UNT Libraries Government Documents Department

International Atomic Energy Agency/Hanford Site shared use of calorimeters

Description: Hanford Site operators combine gamma ray isotopic and calorimetry measurements for nondestructive plutonium assay. Such measurements offer lower variability (particularly for heterogeneous materials) and decreased radiation exposure, cost, waste, intrusiveness, and material handling compared to destructive analysis. Until now, the International Atomic Energy Agency (IAEA) has relied on destructive analysis to perform the most accurate verification requirements for plutonium stored under safeguards at the Hanford Site. It was recognized that using calorimetry could significantly reduce the need for the IAEA to perform destructive analysis. To authorize the operator`s calorimeters for routine IAEA use, however, it was necessary to develop authentication features and perform independent 1558 testing. Authentication features include IAEA control of the hardware and calorimeter operating system software, measurement of certified IAEA standards, sealing of calorimeter chambers, and limited destructive analysis of IAEA selected items. A field test of these authentication features was performed at the Hanford Site in June 1997. The field test also was meant to enhance the credibility the IAEA imputes to calorimetry prior to its implementation. Progress in shared use of the Hanford Site calorimeters is reported.
Date: July 21, 1997
Creator: Welsh, T. L.
Partner: UNT Libraries Government Documents Department

Comparison of calorimetry and destructive analytical measurement techniques for excess plutonium powders

Description: In Dec. 1994, IAEA safeguards were initiated on inventory of Pu- bearing materials, originating from the US nuclear weapons complex, at vault 3 of DOE`s Plutonium Finishing Plant at Hanford. Because of the diversity and heterogeneity of the Pu, plant operators have increasingly used calorimetry for accountability measurements. During the recent commencement of IAEA safeguards at vault 3, destructive (electrochemical titration) methods were used to determine Pu concentrations in subsamples of inventory items with widely ranging chemical purities. The Pu concentrations in the subsamples were determined and contribution of heterogeneity to total variability was identified. Measurement results, gathered by PFP and IAEA laboratories, showed total measurement variability for calorimetry to be comparable with or lower than those of sampling and chemical analyses.
Date: March 15, 1996
Creator: Welsh, T.L.
Partner: UNT Libraries Government Documents Department

Comparison of NDA and DA measurement techniques for excess Pu powders at the Hanford Site: Operator and IAEA experience

Description: Quantitative physical measurements are necessary components of the International Atomic Energy Agency (IAEA) nuclear material safeguards verification regime. In December 1994, IAEA safeguards were initiated on an inventory of plutonium-bearing oxide and scrap items in Vault 3 of the 2736-Z Building of the Plutonium Finishing Plant on the United States Department of Energy`s (USDOE) Hanford Site. The material originated in the United States nuclear weapons complex. The diversity of the chemical form and the heterogenous physical form of the plutonium in this inventory were expected to challenge the target precision and accuracy of methods employed by IAEA: quantitative destructive analytical techniques (which are susceptible to sampling error) and quantitative coincident neutron measurements (which rely on knowledge of the material`s chemical form and purity). Because of the diverse and heterogenous nature of plutonium-bearing scrap, plant operations increasingly have adopted calorimetric techniques both for item inventory measurements and for verification purposes. During the recent advent of IAEA safeguards at Vault 3, a set of destructive and nondestructive methods were applied to a number of inventory items (cans of plutonium-bearing powders) with widely ranging chemical purities. Results of these measurements, gathered by the operator`s and IAEA`s laboratories and instruments as well as by instruments from Pacific Northwest Laboratory and USDOE`s Los Alamos National Laboratory (LANL), are presented and statistically compared.
Date: June 1995
Creator: Welsh, T. L.; McRae, L. P. & Delegard, C. H.
Partner: UNT Libraries Government Documents Department

Genetic Analysis of Oncorhynchus Nerka : 1991 Annual Progress Report.

Description: The 1990 project to develop DNA assessment techniques for the purpose of determining relationships among populations of Oncorhynchus nerka demonstrated differences that had potential for such application. The work was continued in 1991 with specific application of the techniques to develop DNA probes that could be used in separating populations of 0. nerka associated with the lakes in the upper Salmon River, principally those in Redfish Lake. Research included sockeye-kokanee life history studies that might add supporting evidence for assessing the degree of difference or similarity among populations in the lake systems. This report summarizes the annual activities under the work plan.
Date: January 1, 1992
Creator: Brannon, E.L.; Setter, A.L.; Welsh, T.L. & Rocklage, S.J.
Partner: UNT Libraries Government Documents Department

Comparison of NDA and DA measurement techniques for excess plutonium powders at the Hanford Site: Statistical design and heterogeneity testing

Description: Quantitative physical measurements are a n component of the International Atomic Energy Agency (IAEA) nuclear material m&guards verification regime. In December 1994, LA.FA safeguards were initiated on an inventory of excess plutonium powder items at the Plutonium Finishing Plant, Vault 3, on the US Department of Energy`s Hanford Site. The material originl from the US nuclear weapons complex. The diversity of the chemical form and the heterogenous physical form of this inventory were anticipated to challenge the precision and accuracy of quantitative destructive analytical techniques. A sampling design was used to estimate the degree of heterogeneity of the plutonium content of a variety of inventory items. Plutonium concentration, the item net weight, and the {sup 240}Pu content were among the variables considered in the design. Samples were obtained from randomly selected location within each item. Each sample was divided into aliquots and analyzed chemically. Operator measurements by calorimetry and IAEA measurements by coincident neutron nondestructive analysis also were performed for the initial physical inventory verification materials and similar items not yet under IAEA safeguards. The heterogeneity testing has confirmed that part of the material is indeed significantly heterogeneous; this means that precautionary measures must be taken to obtain representative samples for destructive analysis. In addition, the sampling variability due to material heterogeneity was found to be comparable with, or greater than, the variability of the operator`s calorimetric measurements.
Date: June 1, 1995
Creator: Welsh, T.L.; McRae, L.P.; Delegard, C.H.; Liebetrau, A.M.; Johnson, W.C.; Theis, W. et al.
Partner: UNT Libraries Government Documents Department

Analysis of sludge from Hanford K East Basin canisters

Description: Sludge samples from the canisters in the Hanford K East Basin fuel storage pool have been retrieved and analyzed. Both chemical and physical properties have been determined. The results are to be used to determine the disposition of the bulk of the sludge and to assess the impact of residual sludge on dry storage of the associated intact metallic uranium fuel elements. This report is a summary and review of the data provided by various laboratories. Although raw chemistry data were originally reported on various bases (compositions for as-settled, centrifuged, or dry sludge) this report places all of the data on a common comparable basis. Data were evaluated for internal consistency and consistency with respect to the governing sample analysis plan. Conclusions applicable to sludge disposition and spent fuel storage are drawn where possible.
Date: September 12, 1997
Creator: Makenas, B.J.; Welsh, T.L.; Baker, R.B.; Hoppe, E.W.; Schmidt, A.J.; Abrefah, J. et al.
Partner: UNT Libraries Government Documents Department