Investigation of a SPH-based sub-cell homogenization for PHWR using a multi-cell model

Abstract

Superhomogenization (SPH) has gained interest in the industry as a possible method to overcome the inherent limitations of standard homogenization (SH) for full nuclearreactor-core neutronics calculations because its implementation does not require any changes to existing computer codes. Previous work found that single-cell SPH applied to Pressurized Heavy Water Reactors (PHWR) yields virtually no improvement compared to single-cell standard homogenization. This work attempts to improve those results by accounting for neutron leakage across cell boundaries by performing SPH-based homogenization using a 3×3 multi-cell model. The method is evaluated using a 5×5 lattice-cell model and comparing results for single-cell SH, multi-cell SH, single-cell SPH and multi-cell SPH. Results show that multi-cell SPH produces better results than single-cell SPH and multi-cell SH produces better results than single-cell SH. However, multi-cell SPH offers no improvement compared to multi-cell SH, just as single-cell SPH offers no improvement over single-cell SH.