Depletion perturbation theory for burnup dependent microscopic cross sections

Abstract

Depletion Perturbation Theory (DPT) has become a widely accepted method for estimating time dependent sensitivities of a core response, R, to all system data without repetitive depletion calculations. The work here extends DPT to thermal reactor models in which the microscopic cross section data changes during fuel irradiation. The adjoint cross section function is introduced to accomodate the additional system equation describing the cross section burnup dependence. Numerical examples indicate that with minor additional computational effort, the new method can accurately predict depletion sensitivities for reactor models having burnup dependent data.