ERFORMANCE OF THE DIFFUSION AND SIMPLIFIED PN THEORIES FOR BWR PIN-BY-PIN FINE MESH CORE ANALYSES

摘要

Performance of the diffusion and SP3 theories for cell-homogeneous pin-by-pin BWR core analyses is evaluated through comparison with cell-heterogeneous detailed transport calculations by the method of characteristics. Comparisons are carried out in 2x2 multi-assembly geometries, which consist of low- and high- enrichment 9x9 BWR fuel assemblies. Calculation results indicate that the SP3 method gives sufficient accuracy when the cell-homogenization correction is taken into account by the SPH method. Contrary, the diffusion theory shows larger discrepancy.