A PERTURBATION ANALYSIS SCHEME IN WIMS USING TRANSPORT THEORY FLUX SOLUTIONS

摘要

Classical perturbation theory is widely used to calculate changes in reactivity due to variations in system parameters (e.g. material properties, reactor operating conditions, reactor geometry). This paper describes a new scheme to perform classical perturbation theory calculations that are based on transport theory flux solutions, through calculation of currents across all boundaries within a problem. This has been implemented in the reactor physics code WIMS. Group-wise sensitivity coefficients are evaluated using the perturbation methodology. For cases considered in this paper, excellent agreement was observed between WIMS and the Monte Carlo code MONK. Compared to use of diffusion theory, using transport theory was shown using a simple test case to give a more accurate breakdown of the change in reactivity because of a perturbation. This improved accuracy was due to a more accurate calculation of the leakage term.