Short characteristics method for two dimensional heterogeneous Cartesian cells

The short characteristics method for two-dimensional xy-geometry is extended to heterogeneous Cartesian cells. The new method is intended for realistic neutron transport calculation, as for pressurized water reactor assemblies and bundles, without pin cells homogenization. The pin cell is chosen as the basic element for geometrical mapping. Thus, the heterogeneous cells are modeled by a rectangular element with an arbitrary number of concentric rings. Test problems show that the use of this kind of cells allows a minimal geometrical modeling without a significant lost in precision. (authors)