Verification of Cell-Homogenized Whole-Core Transport Calculations in Actual PWR Core Geometry

In this paper, a cell-homogenized whole-core transport calculation is applied to a pressurized water reactor (PWR) core and its prediction accuracy on reactivity and power distribution is verified in comparison with cell-heterogeneous whole-core transport calculation results obtained by the method of characteristics. Recent progress in common computer hardware promotes continuous improvements on core calculation methods. Among several different approaches, a three-dimensional pin-by-pin (fine-mesh) core calculation is considered as one of the candidates of advanced methods. In general, although the fine-mesh core calculation explicitly treats each individual pin, it still has three approximations: cell-homogenization, low-level transport theory (usually the SPN or the diffusion approximation) and few-group treatment. Therefore, the impact of these approximations on core characteristics should be evaluated to confirm the feasibility of the three-dimensional fine-mesh core calculation method. This paper focuses on two former approximations, and the impact of these approximations is evaluated.