Research and Application of Method of Characteristics with P1 Anisotropic Scattering

The method of characteristics (MOC) based on the neutron transport equation with isotropic scattering may encounter problems of negative P0 self-scattering cross-section when performing lattice spectrum calculation after transport correction, which influences the numerical stability. The MOC with P1 anisotropic scattering was proposed in this paper, based on which an MOC code named PEACH-A was developed. The results of PWR cell benchmark problem indicate that PEACH-A code has a high numerical accuracy. The sensitivity analyses were performed for single UO₂ cells, single MOX cells, and combined cells with typical fuel enrichments. The results indicate that it is necessary to employ the P1 scattering for MOX fuels and the UO₂ fuel lattice which consists of fuel pins with large enrichment differences.