Criticality Safety Evaluation for High-Density Spent-Fuel Storage Racks

Abstract

Using as a starting base the high-density spent-fuel storage racks to be put into the Chinshan and Kuoshang nuclear power plants, a series of criticality analyses with various combinations of fuel assemblies and storage rack designs were performed using an AMPX-KENO/XSDRNPM computer code package. The calculated kappainfinity value for the storage pools in the two subject plants using Boral (0.013 g/cm/sup 2/ /sup 10/B) poisoned rack lattices and 3.2 wt % enriched fuel assemblies is 0.900 under conservative assumptions. Considering all the calculation biases and statistical and manufacturing uncertainties, the maximum kappainfinity value is estimated to be 0.929 under normal storage conditions. Variation in water temperature and density or abnormal positioning of fuel assemblies will result only in a negative effect on kappainfinity value.