Group Constants Generation and SPH Correction Applied to the Westinghouse LFR design

This paper presents a neutronic analysis of a simplified version of the Westinghouse lead-cooled fast reactor. The study focuses on the approach for generating the multi-group constants, obtained from Monte Carlo simulations, which are then used in the full-core calculations with deterministic codes. Specifically, this work investigates the possibility of using a set of sub-assembly models instead of a full-core model for the group constant generation when multiple core configurations are considered, to exploit the resulting compu tational advantages. The potential of applying the superhomogenization (SPH) method, through which SPH correction factors are generated and used to improve the accuracy of results obtained by deterministic models, is also explored. The use of super-cell models for non-multiplying regions and theirs adoption for generating SPH correction factors to material data in regions that cause significant neutron flux gradients is also illustrated. The values of keff and the power density distribution show good agreement with the Monte Carlo reference results after cross-section correction, the kinetic parameter Λeff by SPH, and the βeff does not seem to be affected is more sensitive to the correction, although this does not always lead to improved results.