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Uncertainties in geochemical models of natural systems: Implications for performance assessments

Published online by Cambridge University Press:  17 March 2011

Christopher S. Palenik
Affiliation:
Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109-1063, USA
Keld A. Jensen
Affiliation:
National Institute of Occupational Health, Denmark, Lersø Parkallé 105, DK-2100 Copenhagen Ø, Denmark
Rodney C. Ewing
Affiliation:
Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109-1063, USA Department of Nuclear Engineering & Radiological Sciences, University of Michigan, Ann Arbor, MI 48109-2104, USA
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Abstract

Licensing a geologic repository for nuclear waste will be based primarily upon the results of a performance assessment (PA), which evaluates compliance of the repository with radiation exposure limits by modeling the engineered and natural barrier systems over extended periods (104 to 106 years). The properly completed PA must include an analysis of the sources of uncertainty, as well as the range of input parameter values, in order to determine whether the analysis is “robust”, “realistic” or “conservative”. This paper examines the sources of uncertainty that may be encountered in source-term and near-field models in a performance assessment of a repository for spent nuclear fuel by examining the uncertainties in modeling the geochemical behavior of the Bangombé natural reactor in Gabon.

Type
Research Article
Copyright
Copyright © Materials Research Society 2004

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