A strategy for pin power reconstruction based on classic Galerkin variational formulation

In the proposed strategy, the Nodal Expansion Method (NEM) was used for nodal calculation providing the multiplication factor of the problem and the average fluxes on the Fuel Assemblies (FAs) faces. The reconstruction process starts by determining the point flux distributions (through 1D polynomial expansions) that are used as boundary conditions on the FAs faces. Then the 2D neutron diffusion equation discretized by the Galerkin finite element formulation (GFEM method) is used with heterogeneous nuclear parameters and meshes (elements) with dimensions of a pin aiming to provide directly the detailed information inside the FAs. In order to validate the adopted methodology, the results obtained by the reconstruction method are compared with others methods using reference values previously calculated. The results show good accuracy and efficiency of the proposed strategy.