Subgroup method for the high fidelity neutronics code SHARK and preliminary benchmarking

Abstract

SHARK (Simulation-based High-fidelity Advanced Reactor physics Kit) is a numerical reactor software newly developed by Nuclear Power Institute of China (NPIC) based on the full core deterministic heterogeneous transport theoritical framework. SHARK uses subgroup method to characterize the complex heterogeneous resonance self-shielding effects based on a 45-group library. Both 2D/1D Method of Characteristics (MOC) and quasi-3D MOC are developed as the one-step heterogeneous transport solvers. This program is still under development, and recently the ability of steady microscopic-cross-section level problem calculations is established and verified. This paper emphasizes the subgroup methodology and related improvements in SHARK program, which has decisive influences on the final accuracy. The subgroup method applied in this paper can significantly reduce the cost of transport computations from the classical one, which will benefit the heterogeneous core calculations. Based on VERA core physics benchmark problems, the program is preliminarily verified. The results basically show good agreements with the reference solutions, which reveals the simulating accuracy level of the SHARK program for commercial Pressurized Water Reactor (PWR) assemblies.