Group constants generation by Monte Carlo code MCS for LWR analysis

Abstract

This paper presents the generation of few-group constants using the Monte Carlo (MC) code MCS for light-water reactor (LWR) analysis. The few-group constants are fed into the conventional diffusion nodal code to perform neutronic analysis. This study investigates three methods, B1, P1, and CASMO-4E (CM), to obtain the critical spectrum for correcting the cross-section for LWR analysis. The inflow transport correction based on the PN solution is integrated into the MCS in addition to the typical outflow transport correction in the MC codes. A numerical case study comparing the two-step code MCS/PARCS and MCS standalone results is required to determine the best combination in the transport/diffusion two-step to achieve a high-fidelity LWR analysis. Numerical tests with small and large LWR cores show that the CM method combined with inflow transport correction is the most accurate for two-step code MCS/diffusion in terms of the eigenvalues and power profiles.