Surface Pseudo-Source Method of Accounting for Scattering Anisotropy in Many-Group Calculations of VVER Cells

Abstract

A method is developed for solving the many-group neutron transport equation with an anisotropic scattering cross section in cylindrical geometry by a method where the operator is split and the single-group spatialangular parts of the problem are solved by the method of surface pseudosources. The developed procedure is implemented in the RATsIYa option of the WIMS-SH and SVL software systems. It is used to solve a VVER-1000 cell with mixed uranium-plutonium fuel and a VVER-1000 supercell with an absorbing element. The factor K_∞calculated in the transport and linear-anisotropic approximation differs by up to 0.4% in the first cell and up to 2.3% in the second cell.