A 2D/1D Method for Consistent Burnup Parametrization of Cross Sections in SFR Fuel Depletion Calculations

Abstract : The accuracy of neutronic calculations in reactor physics is determined by the quality of the averaged cross sections used to solve the Boltzmann transport equation. As the reactor burns its fuel, a change occurs in the neutronic properties of the media so the averaged cross sections become time-dependent. Several transport calculations are therefore required at the cross section generation stage to perform a burnup (or fluence) parametrization of the data. This paper proposes to use the now well known 2D/1D method to perform this parametrization. The idea of such a strategy is to avoid computationally expensive 3D simulations while overcoming the drawbacks of standard 2D models. The algorithm is applied to produce time-dependent effective cross sections for a SFR fuel assembly with CFV design. The fuel depletion analysis is then conducted in a ``core environment' and results are compared to independent Monte Carlo simulations. Good performances are found both for the evolution of the spatial distribution of isotopic concentrations and the assembly reactivity loss.