Determination of Effective Reflector and Baffle/Reflector Constants for Few-Group Diffusion Calculations

Analysis of critical experiments for cross-section evaluation has been conducted on the basis of one-dimensional four-group diffusion theory calculations that explicitly model the homogenized core and reflector in the radial plane. Such analyses require a reflector representation that models the leakage process as accurately as feasible. The development and testing of few-group ENDF/B-V based light water reflector constants for use in diffusion theory derived to reproduce leakage and other reaction rates from reference multifast group transport calculations are described. This work has been extended to parameterize similar higher order transport calculations with two- or four-group constants valid for application to typical pressurized water reactor baffle/reflector configurations as represented in coarse mesh diffusion (PDQ) representations.