On computing the eigenvalue spectrum and elementary solutions of multigroup diffusion equations for neutron multiplication eigenvalue problems

The aim of this article is to describe a numerical scheme for the generation of the eigenvalue spectrum and elementary solutions of local multigroup multiplication eigenvalue equations within the framework of spectral nodal diffusion methods. In contrast to the scheme that is currently used by other investigators for eigenvalue spectrum generation, the scheme described here is able to treat without further ado an arbitrary number of energy groups, incorporating easily energy group transitions in neutron outscattering events. We illustrate these positive features with numerical results for a four-group test problem, and we close this article with concluding remarks.