Optimization of a Calculation Scheme for the Treatment of Plutonium Recycling in Pressurized Water Reactors

The EPICURE experimental program provides a complete and high-quality experimental database for evaluating the uncertainties in reactor physics calculations of plutonium-recycling pressurized water reactors. To understand possible discrepancies between experimental values and values calculated with the conventional scheme, a study is performed of the major physics approximations involved in the calculation of heterogeneous Mixed OXide-UO₂-fueled cores. This study determines the origin of the significant discrepancies between the calculated and the measured power distributions. An optimized calculation scheme is developed based on the use of S_n transport calculations and on a refined energy group structure. Its application to the analysis of EPICURE experiments results in very satisfactory agreement.