Hydrologic Uncertainty Assessment for Decommissioning Sites: Hypothetical Test Case Applications

Meyer, Philip D ; Taira, Randal Y

Pacific Northwest National Laboratory (U.S.)

关键词: Leaching;    12 Management Of Radioactive Wastes, And Non-Radioactive Wastes From Nuclear Facilities;    Hydrology;    Sensitivity Analysis;    Radionuclide Migration;   

DOI  :  10.2172/781855
RP-ID  :  NUREG/CR-6695;PNNL-13375
RP-ID  :  AC06-76RLO1830
RP-ID  :  781855

美国|英语

来源: UNT Digital Library

【 摘 要 】

This report uses hypothetical decommissioning test cases to illustrate an uncertainty assessment methodology for dose assessments conducted as part of decommissioning analyses (see NUREG/CR-6656). The hypothetical test case source term and scenarios are based on an actual decommissioning case and the physical setting is based on the site of a field experiment carried out for the NRC in Arizona. The emphasis in the test case was on parameter uncertainty. The analysis is limited to the hydrologic aspects of the exposure pathway involving infiltration of water at the ground surface, leaching of contaminants, and transport of contaminants through the groundwater to a point of exposure. The methodology uses generic parameter distributions based on national or regional databases for estimating parameter uncertainty. A Bayesian updating method is used in one of the test case applications to combine site-specific information with the generic parameter distributions. Sensitivity analysis and probabilistic simulation are used to describe the impact of parameter uncertainty on predicted dose. Emphasis is placed on understanding the conceptual and computational behavior of the dose assessment codes as they are applied to the test cases. The primary code used in this application was RESRAD v.6.0 although D and D v.1.0 results are also reported. The methods presented and the issues discussed are applicable to other codes as well.