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Criticality Evaluation of Degraded Internal Configurations for a 44 BWR Waste Package

The purpose of this calculation is to perform an example criticality evaluation for degraded internal configurations of a boiling water reactor (BWR) waste package (WP) containing 44 spent nuclear fuel (SNF) assemblies. The BWR assembly design considered is based on the General Electric (GE) 8x8 assembly (see section 5.1). Depletion analyses for various assembly average enrichment and burnup (expressed as gigawatt days/metric ton Uranium; GWd/MTU) combinations are performed using the SAS2H/ORIGEN-S sequence of SCALE 4.3 (CSCI:30011-2002; Ref. 7.5).



The objective of this calculation is to evaluate the required minimum burnup as a function of initial boiling water reactor (BWR) assembly enrichment that would permit loading of spent nuclear fuel into the 44 BWR waste package configuration as provided in Attachment IV. This calculation is an application of the methodology presented in ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2003). The scope of this calculation covers a range of enrichments from 0 through 5.0 weight percent (wt%) U-235, and a burnup range of 0 through 40 GWd/MTU.