Optimized Method for Solving Boltzmann Transport Equations in Subgroup Method of Resonance Treatment

This study presents an optimized subgroup transport equation solving method to enhance the computational efficiency of resonance calculations in high-fidelity reactor core simulations. By consolidating all the resonance groups into an equivalent single group and performing fixed-source calculations only for the representative subgroup cross-sections, this method significantly reduced the computational burden compared to the conventional subgroup method. Validation studies on single-cell, 2D assembly, and 3D assembly problems demonstrated that the proposed method achieves computational accuracy comparable to the conventional approach while requiring fewer fixed-source equations. This advancement offers a promising solution for improving the efficiency of resonance calculations in high-fidelity reactor core simulations, paving the way for more accurate and computationally efficient modeling of complex reactor systems.