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

• Published in: Annals of nuclear energy Vol. 47; pp. 53 - 61
• Main Authors: Akbari, M., Minuchehr, A., Zolfaghari, A., Khoshahval, F.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2012
• Subjects: Energy group structure; NJOY data processing; Optimization; Thermal lattices; WIMS library; Energy group structure; WIMS library; Thermal lattices; NJOY data processing; Optimization
• ISSN: 0306-4549; 1873-2100
• DOI: 10.1016/j.anucene.2012.02.016

► A heuristic method is applied to optimize WIMS energy group structure for thermal lattices. ► The optimal energy structure includes 11 fast, 17 resonance and 41 thermal groups. ► The 6.67eV resonance of U-238 has significant effect on the results. ► The optimized structure obtains more precise results in comparison with the original structure. 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-UO2 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.