Neutron Resonance Heterogeneity Effect in the Vicinity of a Gross Region Interface

A simple and convenient method is developed to account for the neutron resonance mismatches due to the composition dissimilitude in the vicinity of gross region interfaces. It is shown that the effective resonance cross sections near a region interface can be obtained from the table-look-up of a cross-section set. The numerical results obtained with the present method are shown to be in an excellent agreement with the exact calculations using a computer code.