First in-pile experimental results of high-plutonium-content oxide fuel for plutonium burning in fast reactors

An experimental program focused not only on the study of high-plutonium-content mixed-oxide fuels but also on more advanced "Pu without U" fuel concepts has been launched in the framework of the Consommation Accrue de Plutonium dans les RApides (CAPRA) project. First results of the in-pile and out-of-pile behavior of high-plutonium-content fuels with uranium, such as (U-55%,Pu-45%) O-2, and (U-55%,Pu-40%,Np-5%) O-2, and also without uranium, such as (Pu-44%,Ce-56%,)O-2, are now available. In particular, the Irradiation a FOrt Pu (IFOP) experiment in the SILOE reactor and the TRAnsmutation and Burning of ActiNides in Triox carrier (TRABANT1) experiments in the High Flux Reactor are presented and the results are analyzed: Up to a burnup of 1.5 at. %, destructive examinations of the IFOP pin have shown that the high-plutonium-content oxide fuel with a large central hole presents the usual global behavior (good pellet integrity, fuel microstructure). The TRABANT1 oxide fuel pin with a 40% Pu and 5% Np content demonstrates that a burnup of 9.5 at. % can be reached without failure by a high-plutonium-content fuel. However, the TRABANT1 pin 1 (oxide pin with 45% Pu), which had run under severe conditions, has failed at similar to 7 at. % burnup. Destructive examinations of these pins will give more evidence on the causes of the failure. The low-oxygen-to-metal fuel column of (Pu, Ce)O2-x melted, thus confirming the poor conductivity of this fuel.