GI-XRD ans HERFD-XANES characterization of high-temperature annealed Cr-doped UO2 samples implanted with iodine, cesium and molybdenum

We study the migration and chemistry of 3 fission products (FP), iodine, cesium and molybdenum in an ATF nuclear fuel (Cr-doped UO2) at high temperature and as a function of the atmospheric conditions (reductive or oxidative). To do so, stable isotopes of I, Cs and/or Mo are introduced by ion implantation at the surface of Cr-doped UO2 pellets. Pellets are then annealed under reductive or oxidative conditions between 1000 and 1600°C. GI-XRD measurements will allow to characterize the compounds potentially formed by chemical interaction between FP and between FP and the fuel. The combination of GI-XRD and HERFD-XANES at the U M4-edge will allow to characterize the oxidation of the material (crystallographic phases, O/U ratio, U oxidation degree). The evolution of chromium speciation in samples will also be investigated at the Cr K-edge.