Finite difference method for 3D multi-group neutron diffusion equation based on large-scale parallel computation

Nuclear design and fuel management of submarine reactors and NPP reactors are based on solving 3D multi-group neutron diffusion equation accurately and efficiently. One of the methods for this equation is finite difference method (FDM), which is simple, accurate and mature. However, the computation burden of FDM is huge and the memory requirement is high, thus limiting FDMs scale and application scope. In this paper, FDM for 3D multi-group neutron diffusion equation based on large-scale parallel computation is researched. Mesh-centered FDM is used to discrete the neutron diffusion equation. Large-scale parallel computation is realized by domain decomposition based on MPI, and its accelerated with multi-group multi-domain coupled PGMRES algorithm. ParaFiDi code is developed on high performance cluster and verified by several benchmarks such as IAEA3D and PHWR. Numerical results demonstrate that ParaFiDi code could obtain good efficiency and accuracy.