Two-dimensional heterogeneous calculation of irregular lattices

A version of the passage probability, method for calculating irregular lattices is described. The characteristics (emission and collision probabilities) of individual cells are determined by the collision probability method. Thefluxes in the entire lattice are calculated using the balance equations,for currents between cells. An algorithm is proposed for automatically partitioning an irregular lattice into individual cells and for improving the numerical integration scheme in calculating the characteristics. The computational results obtained for several model lattices by passage probability and Monte Carlo methods are compared.