Development of the 3D SPN transport solver KANECS for nuclear reactor analysis

For practical reactor analysis, a low-order transport approximation such as simplified spherical harmonics (SP N ) has become widely used due to its improved accuracy over diffusion and lower computational cost compared to spherical harmonics (P N ) and discrete-ordinate (S N ) methods. This paper introduces and verifies KANECS, a new neutronic solver that employs the SP N approximation and continuous Galerkin finite-element method (CGFEM) for angular and spatial discretization respectively, to solve the 3D steady-state multigroup neutron transport equation in Cartesian geometry. For the numerical verification, the KAIST and C5G7 benchmarks were selected. The results show that KANECS predicts with promising accuracy the k eff and power distribution, fairly close to the ones of transport approach. Consequently, KANECS demonstrates that it can effectively perform a pin-by-pin core analysis.