Polar-wise interface current characteristics method - 109

The polar-wise interface current characteristics method (PICCM) is introduced in order to reduce the computational inefficiencies of ray tracing inherent in the Collision Probability Method (CPM) and the Method of Characteristics (MOC). The escape probability and contribution probability equations are introduced to determine the polar-wise outgoing current and region fluxes for each cell. These two equations are derived directly from the MOC solution of each cell. For the pin-cell problem, the results show that the computational time is reduced by about 20% with PICCM compared to the original MOC solver of the CPM3 code, with only minor differences in the prediction of the eigenvalue. For a 14x14 PWR lattice problem, PICCM provides about a factor of 6 reduction in the execution time compared to MOC, with less than 20 pcm of reactivity error and a maximum 0.32% error of the pin power distribution. (author)