Transport/Diffusion Equivalence Method in the EdF Neutronic Calculation Scheme: Application to EPICURE Experiment Interpretation

Abstract

EDF (Electricite De France) has developed its own neutronic calculation scheme for the management and operation of the installed nuclear capacity in France. It is based on heterogeneous transport calculation for each type of assembly, providing homogenized cross sections libraries for homogeneous or pin-by-pin core calculations using diffusion theory. Qualification of this methodology depends to a large extent on the transport/diffusion equivalence code HERMES which renders the transport code homogenized cross sections compatible with the diffusion-based calculation of core heterogeneities (water holes, poison, MOX-U02 interface, etc.). In this paper, after outlining the EDF neutronic design scheme, we describe in detail the physical postulates selected for the equivalence model HERMES, illustrating by simple examples the judiciousness of these options. Results obtained on qualification of the EDF methodology will then be presented together with interpretation of experimental measurements of the fine power distribution in a core recycling plutonium carried out during the first stage of the EPICURE experimental program.