An investigation for an optimized neutron energy-group structure in thermal lattices using Particle Swarm Optimization

摘要

This paper describes an improvement pertaining to the energy group structure of WIMS code in thermal lattices using Particle Swarm Optimization method. The 69 group WIMS cross section library for the specified energy structure is generated using NJOY data processing system. The integral parameters of thermal reactor lattices BAPL-UO_2 and TRX are calculated by WIMSD5 code using the generated library. These parameters are compared against the results of continuous energy MCNP-4C code and are served for evaluating the energy group structure. Minimization of the errors in integral parameters and multiplication factor is considered as the objective function. Calculation results show that for thermal reactor lattices where the enrichment of uranium is slight, the optimized energy group structure obtains more precise results comparing with the original WIMS structure.