The NILO-CMFD Method for Iteratively Solving Coupled Neutron Transport–Thermal Hydraulics Problems

The coarse-mesh finite difference (CMFD) method is commonly used to accelerate the iterative convergence of single-physics neutron transport problems. For multiphysics problems, cross sections depend on temperature and density, both which fission heat source; resulting nonlinear feedback can significantly degrade performance CMFD even cause instability. In this paper, we propose, for a class one-dimensional (1-D) model new nonlinearly implicit low-order (NILO) (NILO-CMFD) acceleration improve CMFD-based methods solving loosely coupled Our numerical testing Fourier analysis show that 1-D NILO-CMFD achieves same rapid rate