Multicell Correction Method for Treatment of Heterogeneities in Full-Core Calculation of CANDU-Type Reactors

This paper presents a multicell correction method that has been developed and implemented in the code suite WIMS-AECL/RFSP to capture the effects of the lattice-cell neighborhood while maintaining the basic structure of the single-cell-based reactor-physics methodology traditionally used for Canada Deuterium Uranium (CANDU)-reactor calculations for decades. To validate the effectiveness in treating the core-reflector interface heterogeneity as well as the checkerboard-voiding scenario, the results of WIMS-AECL/RFSP calculations (with and without the multicell correction) are compared with the results of MCNP5 full-core calculations for CANDU-type reactors. The presented results show that the multicell correction method is effective, generic, and capable of capturing the heterogeneity effects of the neighborhood in CANDU-type reactors.