Optimization of multi-group energy structures for solving the neutron transport equation

\nWe develop a framework to determine an optimal broad group structure of the energy variable when solving the neutron transport equation, starting from a fine structure. This broad group structure is required to perform the energy condensation method, where the fine group cross sections are collapsed into the broad group cross sections. In this optimization work, we study the objective function based on the error of the reaction rates and the k-effective as well. Moreover, together with the automatic coarse energy (ACE) algorithm proposed in [1] and the particle swarm optimization (PSO) usually applied to optimize the broad group structure, we introduce the Leave Group Out (LGO) and Add Group In (AGI) approaches. Numerical results for the core calculation are investigated to illustrate the performance of the proposed algorithms.\n