Assembly Rehomogenization Methods for Reactor Analysis

The need to model the effect of the assembly environment on the neutronic data has been felt since Smith’s topical article on assembly homogenization techniques. Indeed, simply homogenizing the cross sections using the spatial distribution and energy spectrum of the neutron flux calculated in a single assembly with reflective boundary conditions, neglecting the effect of the proximity of other types of assemblies, can induce inaccuracies affecting the results of core calculations. Many approaches have been proposed to take into account the real environment of the assembly. The purpose of this article is to review these methods to allow the reader to compare them.