Study of a mixed fleet of breeder sfr and epr supplied with leu and mox fuels to balance the plutonium inventory

International audienceScenarios of the evolution of the French nuclear fleet are simulated with the aim of improving spent fuel recycling, natural resource savings and wastes reduction. These scenarios are developed by CEA, EDF and AREVA, following conservative assumptions in terms of technology, safety, regulation and costs. In the next decades, the SFR demonstrator ASTRID paves the way to the deployment of a few fast reactors used to consume PWR MOX spent fuel in priority. In the 2090 to 2120 period, the number of SFR goes on growing. The fleet eventually comes to a mix of breeder SFR and EPR (European Pressurized water Reactor) supplied with LEU and MOX fuels. Such a fleet composition enables the stabilization of spent fuel and plutonium inventories. Previously, a steady state regime was reached in the next century, thanks to a fleet composed of $\sim$40% SFR. For a further understanding of this kind of nuclear systems, a new methodology has been applied. This methodology was recently developed to put into equations the equilibrium conditions of nuclear power systems composed of various reactor types. It relies on quantities and grades of plutonium batches that balance through the U/Pu cycle, accounting for the Pu241 decay between a spent fuel unloading operation and its recycling into a new fuel. In-pile irradiation in each reactor type is simulated by 3 functions plutonium consumption, production, and evolution of its grade. Fleets with the less SFR are now favored, since SFR are reputed to be more expensive than thermal reactors. Results show that the fraction of SFR in the fleet can be reduced of around 10% in comparison to the fleet previously deployed. However, the fleet composition which minimizes the SFR fraction at equilibrium leads to plutonium contents in EPR MOX fuels near the safety limit which is currently accounted for