Ph.D. Proposal Presentation by Benoit Forget
Friday, February 11, 2005

(Dr. Farzad Rahnema, Chair)

"A Three-Dimensional Heterogeneous Coarse Mesh Transport Method for Reactor Calculations"

Abstract

The current generation of methods for whole-core neutronic reactor analysis is still based on diffusion theory and relies heavily on spatial homogenization.  These methods work well for the operating generation of nuclear reactors but the trend towards more compositional heterogeneity in assembly and core of advanced and Generation IV reactors will push these methods beyond their accuracy limits.  The goal of this PhD proposal is to develop an efficient three-dimensional whole core neutronic method/tool which is based solely on transport theory, does not de-couple the transport phenomena between nodes, does not rely on homogenization or discontinuity factors, contains an accurate self-contained flux reconstruction procedure and does not restrict the size of the coarse meshes.  This method will thus eliminate the errors associated with spatial homogenization and diffusion theory. These characteristics make the new method a flexible tool for a variety of reactor designs and spectra.  The new method is expected to be substantially faster than fine mesh transport methods since the computational burden is almost entirely shifted to the pre-computation phase.  This work proposes the use of both stochastic methods by means of Monte Carlo and deterministic methods for the pre-computations.  The proposed research also involves the development of new realistic numerical benchmark problems for code evaluation.

The main goal of the proposed project is to extend the non-variational coarse-mesh transport method to 3D geometry as a computational tool for the existing class of reactors as well as Generation IV reactors.  The new method will allow polynomial expansion for the representation of the interface current in space and angle to reduce the amount of pre-computation.