Environment-Insensitive Equivalent Diffusion Theory Group Constants for Pressurized Water Reactor Radial Reflector Regions

A novel one-dimensional approach, which combines the“nodal equivalence theory” and response matrix homogenization methods, is developed for generating equivalent few-group nodal diffusion parameters for the radial reflector of a pressurized water reactor. This nodal reflector model has the advantage that it is much less sensitive to reactor core conditions than conventional nodal equivalence theory models. A special one-dimensional nodal equivalence theory reflector model is described and applied in numerical experiments to investigate the significance of the environment dependence of such models. Numerical results are presented to confirm the environment insensitivity of the new model and to illustrate its feasibility for application to multidimensional nodal reactor analysis.