DYNAMIC FLUX SYNTHESIS USING TRIAL FUNCTIONS

Abstract

For complex and detailed reactor models, the solution of the space-dependent neutron kinetics equations by conventional methods can become prohibitively expensive in terms of computational cost. As an aid in such evaluations, a method of solution involving flux synthesis from trial functions that are available from past finite-difference simulations is developed. The theoretical and physical aspects of the CANDU-PHW reactor that provide the basis for the assumptions used in the application of the method are outlined, and the basic mathematical theory of applying trial functions to the solution of the two-group time-dependent neutron diffusion equation is developed. A computer code DEUTERONOMY based on this analysis was written and validated against both analytic and numeric solutions of reactor transients. The usefulness of trial function flux synthesis is examined in comparison with alternative methods such as finite differencing and modal expansion techniques.