Revised interface-current relations for the unit-cell transport problem in cylindrical and spherical geometries

Escape and transmission probabilities, defined in terms of both the region the neutron originates from and the region it penetrates, are used to develop new interface--current relations for unit-cells with an arbitrary number of annular regions in cylindrical and spherical geometries. Comparisons with currents, obtained in terms of standard transmission and escape probabilities, as well as with accurate results reported in the literature, are presented for selected situations, showing significant discrepancies between the two models.