改良型遺伝アルゴリズムによる沸騰水型原子炉の炉心装荷パターン最適化

抄録

A search method based on genetic algorithms (GA) using the deterministic operators has been developed to generate optimized boiling water reactor (BWR) loading patterns (LP). The search method uses an improved GA operator, that is crossover, mutation, and selection. The handling of encoding technique and constraint conditions is designed so that the GA reflects the peculiar characteristics of the BWR. In addition, some strategies such as
elitism and self-reproduction are effectively used to improve the search speed. LP evaluations were performed with a three-dimensional diffusion code that coupled neutronic and thermal hydraulic models. Strong axial heterogeneities and three-dimensional-dependent constraints have always necessitated the use of three-dimensional core simulators for BWRs, so that an optimization method is required for computational efficiency.
The proposed algorithm is demonstrated by successfully generating LPs for an actual BWR plant applying the Haling technique. In test calculations, candidates that shuffled fresh and burned fuel assemblies within a reasonable computation time were obtained.