Advanced plutonium PWR fuel assemblies R and D in France

Management of the plutonium cycle associated with the fuel, and the fuel itself since its is continuously renewed so that improvements can be made to it in the short or medium term, play an important role in optimizing existing reactors and in achieving ambitious objectives for the use of natural resources, the management of ultimate waste and control of the plutonium inventory. After it decided that the fast neutron reactor system was not going to expand as quickly as initially predicted, France committed itself towards recycling plutonium in pressurized water reactors as earlier as 1987. A major R and D program was started in the mid 1970's with critical mock-up experiments (EOLE, MINERVE) and irradiation experimental rods in test reactors and thein in power reactors. The first MOX assemblies were loaded into a 900 MWe PWR in 1987 to achieve a balanced cycle three years later. Since then, the R and D program undertaken by the CEA in close relation with the industrialists concerned (EdF, Framatome-ANP, COGEMA) has been aimed at achieving identical management of MOX assemblies and standard UO2 assemblies. This first step has now been completed successfully, and the CEA is now committed to an R and D program intended to move on to plutonium management with multi-recycling in existing or future pressurized water reactor (EPR). Two systems are being examined in parallel. The first system, CORAIL, maintains the 17x17 structure of the existing assembly, but due to a new layout of MOX rods in the assembly, will change to use cores in which all assemblies will be of the same type with plutonium. This new core management could be used in reactors by the middle of the next decade, due to its smoothly evolutionary nature. The second system, APA, can be used to introduce plutonium fuels on an inert matrix. This could modify the mechanical structure of the assembly and the geometry of the rods themselves (annular or cross-pattern rod layout, etc). While maintaining, as far as possible, external compatibility. The planned developments will require more validation work than the previous case, followed by a core management change in the 2020 - 2030 decade. Scenario studies based on the different core cycle management systems studied show that multi-recycling of plutonium in pressurized water reactors is a means of stabilizing the plutonium inventory in French power stations (CORAIL), or even reducing it with more innovative core management systems (APA). (author)