Determination of equivalent diffusion theory parameters. Final report

Ideal equivalent group diffusion theory constants are defined in a rigorous manner and the failure of standard flux-weighting procedures to yield these ideal constants is discussed. An iterative scheme based upon the Response Matrix Technique is then developed for finding improved two-group, two-dimensional equivalent group diffusion constants for symmetric assemblies. The use of these constants in a full-core criticality calculation results in a much more accurate prediction of integrated absorption rates and power densities than those predicted using the standard flux-weighted constants