An improved scheme for calculation of the radiation transport in greatly heterogeneous media and voids

A new method of weights choice in the known weighted WDD scheme of the discrete ordinate method for the radiation transport equation in cylindrical $(r,z)$ geometry is proposed. In each cell of spatial grid for each node of angular quadrature weights are chosen so that angular distribution, obtained by balance WDD scheme, would be in a good quantitative and qualitative agreement with solution, obtained by nonconservative characteristics scheme. The method may be extended to other geometries.