Environment-independent homogenized parameters for neutron diffusion in non-symmetric slabs

Properly defined group diffusion parameters are needed in order to describe accurately the neutronic behavior of reactor cores by means of equivalent homogeneous regions, or nodes. First, important characteristics of the reactor, such as the effective multiplication factor and nodal reaction rates, are to be preserved. Then, as neutron flux and current are continuous functions of the position, a basic requirement should be that fluxes and currents have the same boundary values for the actual node and its equivalent homogeneous counterpart. Here a method is presented which, by assuming linear anisotropy for the homogenized medium, is able to determine environment independent homogenized parameters for neutron diffusion in nonsymmetric slabs. Some test problems are presented and the appropriate extension of the method to multidimensional geometries is briefly discussed.