Performance of ENDF/B-VIII.0 library for VVER reactors criticality safety, fuel depletion and reactor dosimetry applications

Abstract

The latest ENDF/B nuclear data library released in 2018 is the result of a new international approach to develop evaluated nuclear data for general purpose applications. In order to use the latest ENDF/B-VIII.0 nuclear data library in safety analyses, validation calculations for available benchmark experiments and comparison calculations for previous library versions are required. Validation of this new library for three important reactor areas, criticality safety, fuel depletion and reactor dosimetry, was performed with MCNP6, KENO-VI and Serpent 2 codes for VVER application. Criticality safety and fuel depletion results show better agreement with ICSBEP and SFCOMPO benchmark database cases for the ENDF/B-VIII.0 library when compared with previous libraries including ENDF/B-VII.1. On the other hand, using the latest VIII.0 library for VVER reactor dosimetry applications including neutron fluence on reactor pressure vessel and ex-vessel neutron fluence activation monitors is not recommended since the library gives significantly lower neutron fluence and detector activities when comparing to number of alternative nuclear data libraries. Two nuclides that are dominantly responsible for the discrepancies between the latest ENDF/B library and other libraries were identified as O-16 and Fe-56. The conclusions are limited to VVER application where the water gap between the reactor core and the pressure vessel is significantly decreased compared to PWR