Validation of standard neutron data libraries for LWR storage pools and transport casks criticality safety evaluations

Abstract
This paper addresses the assessment of MCNPX-2.5.0 criticality calculations using continuous energy cross section libraries based on JEF-2.2, JENDL-3.3, ENDF/B-6.8, and the recently released JEFF-3.1 data files. For this purpose, validation calculations were performed for a suite of benchmarks from the International Handbook of Evaluated Criticality Safety Benchmark Experiments. The benchmarks were selected on the basis of their similarity to designs found in today's Light Water Reactor (LWR) compact storage pools and transport casks, including MOX fuel rod assemblies, and in total comprised as much as 149 cases. In order to define the ranges of applicability of the used calculational methods and to detect possible trends, the spectrum-related characteristics of the modeled critical experimental configurations were analysed. It is found that the recently released JEFF-3.1 library improves the older JEF-2.2 compilation and leads to a value for the weighted average of the normalized eigenvalues very close to unity. All libraries have in common that any evidence of a statistically significant trend in the normalized eigenvalues versus both spectrum-related characteristics and experimental design parameters could not be found.