Generation and validation of a new WIMS-D library based on ENDF/B-VIII.0

The WIMSD-5B transport code is a deterministic tool for nuclear reactor core design and fuel management. It can efficiently handle pin-cell and supercell models and calculate homogenized cross sections, which are essential for reactor physics calculations. It is used by core design packages such as the CORD-2 package, developed at the Jožef Stefan Institute, and SEANAP developed by Universidad Politécnica de Madrid (UPM). The WLUP update project https://www-nds.iaea.org/wimsd demonstrated the way to update the WIMS-D libraries with different evaluated nuclear data libraries, including ENDF libraries up to version ENDF/B-VII.1. Using an updated version of the procedure, a new WIMS-D library based on the ENDF/B-VIII.0 data was developed to improve the accuracy of core design calculations. Several improvements to the library were made and the effects of each individual improvement was demonstrated using a 3×3 supercell benchmark model that is representative of a typical pressurized water reactor. Finally, the performance of the library over a diverse set of neutron transport problems was tested for, to ensure no regressions were introduced.