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

• Published in: Progress in nuclear energy (New series) Vol. 104; pp. 251 - 263
• Main Authors: Pessoa, Paulo O., Araujo, Lenilson M., Silva, Fernando C.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.04.2018; Elsevier BV
• Subjects: Accuracy; Efficiency; Finite element analysis; Finite element method; Flux (rate); Fluxes; Galerkin method; Mathematical analysis; Nodal calculation; Nuclear fuels; Pin power reconstruction; Polynomials; Reconstruction; Strategy; Studies; Finite element method; Pin power reconstruction; Nodal calculation
• ISSN: 0149-1970; 1878-4224
• DOI: 10.1016/j.pnucene.2017.10.005

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. •A new method for pin power reconstruction is presented.•The method uses discretization by finite elements of 2D neutrons diffusion equation.•The discretization is done using homogeneous meshes with dimensions of a fuel pin.•The discretization is combined with point flux distributions on the four node surfaces.•The maximum errors in power reconstruction occur in the peripheral of the active core.