Impact of new nuclear data on neutronic calculations of the OPAL Reactor using Serpent

Abstract

Nuclear data, such as neutron cross sections, fission yield data and decay data, are essential to perform neutron transport calculations. This data is constantly being refined as new measurements are performed and computational power increases allowing for the calculation of higher fidelity nuclear models. In this work the nuclear data libraries ENDF/B-VII.0, ENDF/B-VII.1 and ENDF/B-VIII.0 are benchmarked against experimental data obtained from the Research Reactor OPAL in Sydney, Australia. ENDF/B-VIII.0 is currently in the beta stage of testing, though all the criticality-sensitive data has been frozen. Calculations of critical configurations, control rod worths and burnup of 6 operating cycles of OPAL were performed. This new library yields results that are consistent with both the experimental data available and calculated data from previous work, with the results produced using the new library providing similar or improved agreement with experimental data when compared to other code benchmarks of the OPAL Reactor. Isotopic evolution of key species within the core over these 6 cycles is also presented, including important fission product poisons, fissile isotopes and fertile isotopes. While no experimental data exists on the specific composition of any spent fuel from these cycles, differences in the material inventory are noted between calculations using the new library and older ENDF/B evaluations.