Progress on the reevaluation and validation of the n+ 233 U neutron cross sections

Abstract

A re-evaluation of 233U neutron cross sections in the resolved resonance region, coupled to the use of recommended thermal neutron standards and the newly evaluated prompt fission neutron spectra (PFNS) at the thermal point with lower average energy is presented. Analysis on the benchmarks related to 233U solutions is in progress at the Oak Ridge National Laboratory, the International Atomic Energy Agency, and the Jozef Stefan Institute. Following the issues identified in the ENDF/B-VIII.0 nuclear data library in the underestimation of the fission cross sections and in the strong negative gradient observed in critical assemblies, this work reports several steps forward in resolving those issues.