A linear prolongation CMFD acceleration for two-dimensional discrete ordinate k-eigenvalue neutron transport calculation with pin-resolved mesh using discontinuous Galerkin finite element method

Abstract

The development and extension of the lp-CMFD acceleration scheme to the 1D Discontinuous Galerkin Finite Element Method (DGFEM) SN neutron transport problem was recently reported. However, the extension to 2D DGFEM neutron transport problems with pin-resolved unstructured mesh for high fidelity neutron transport simulations has not been previously investigated. In this paper, a projection operator for lp-CMFD is developed to project the linear additive flux to the pin-resolved unstructured mesh for DGFEM SN. To demonstrate its effectiveness on different coarse mesh geometry shapes and sizes, two test problems are presented: the 2D C5G7 problem and a hexagonal type reactor problem. It was found that the projection operator developed for lp-CMFD is straightforward to implement in 2D DGFEM SN with pin-resolved unstructured mesh and is stable and more effective than the other CMFD variants for two test problems. The method developed here is shown to be effective and can be applied in realistic reactor geometries for existing DGFEM neutron transport codes.