The Impact of the Radial Reflector on the 8-Group Cell Averaged Cross-Sections for the SCWR 62-Element Lattice Cell

Abstract

A single lattice cell calculation (assuming an infinite lattice) has historically been used to establish the few energy-group nuclear data required for full core simulations with deterministic codes (except for the Advanced CANDU Reactor [10]). Even though this approximation is accurate enough in the center of the core, since the flux on all cell boundaries is uniform, it turns out to be relatively inaccurate on the edge due to the presence of the reflector. This paper presents the impact of the radial reflector on the 8-group cell-averaged cross-sections of the SCWR 62-element lattice cell. For this purpose, multicell calculations have been carried out with the DRAGON code and compared to the infinite lattice simulation to determine the changes of neutronic properties due to the radial reflector. The results show that cells in contact with the reflector are quite impacted and a minimum of two fuel cell types should be added to the infinite lattice simulation to take into account the environment on the edge of the core.