Study of plutonium reprocessing in PWR with the CLASS tool

Nicolas Thiolliere, Fanny Courtin


Dynamic fuel cycle simulation codes model evolving nuclear fuel cycles, and calculate nuclides inventories and material flows in each unit of the cycle. In the nuclear fuel cycle simulation code CLASS (Core Library for Advanced Scenario Simulation), a Fuel Loading Model (FLM) builds a fresh fuel fulfilling the reactor criticality requirement, depending on the available fissile material. Then, a mean cross-sections predictor calculates the mean cross-sections required to perform the fuel depletion in a short calculation time. This contribution presents the elaboration of these models in the case of a PWR- MOXEUS fuel (MOX on Enriched Uranium Support), which allows plutonium mono-recycling and multi-recycling in PWR. These models are built using neural networks. These predictors are trained on a databank composed of 1000 PWR infinite assembly depletion calculations performed using the software MURE (MCNP Utility for Reactor Evolution) based on the transport code MCNP (Monte- Carlo N Particle). A scenario in which PWR MOXEUS models are also tested on a balancing scenario is presented. The complex evolution of MOXEUS fresh fuel isotopic composition during the scenario is highlighted. Finally, a sensitivity studies based on a set of fuel cycle simulations performed from a precise design of experiment has been done. This work shows preliminary results for plutonium stabilization and incineration capabilities in a fuel cycle composed by PWR.