Application of SPH Method for Sodium Fast Reactor Analysis

In this study, the capability of the DYN3D-Serpent codes system to simulate highly heterogeneous sodium-cooled fast systems was investigated. The BFS-73-1 critical assembly was chosen for the investigation. Initially, a 3D full model of the BFS-73-1 critical assembly was simulated using the Serpent Monte-Carlo (MC) code, and the basic neutronic characteristics were evaluated and compared against experimental values. This part meant as a first step towards the use of the Serpent MC code as a tool for preparation of homogenized group constants, and as a reference solution for code-to-code comparison with the DYN3D code. At the second part of the investigation, the BFS-73-1 critical assembly was modeled using the DYN3D code with few-group cross-sections generated by the Serpent MC code. It was suggested that for highly heterogeneous systems, such as the BFS experiments, the Superhomogenization (SPH) method should be applied to correct the few-group cross-sections of the different regions of the system. The SPH method is described and demonstrated for the BFS-73-1 critical assembly. It is shown that the application of the SPH method improves the accuracy of the DYN3D nodal diffusion solution, and therefore, it can be considered as a promising candidate of homogenization method for pin-by-pin calculations of sodium-cooled fast systems.