Characterization and heading of irradiated fuels and their chemical analogs

This work presents results of leaching experiments under deionized water and under synthetic granite at room temperature in air using spent fuel (UO2 and MOX LWR fuels) and the chemical analogues, natural UO2 and SIMFUEL. The experimental conditions and procedure for irradiated and non-irradiated materials were kept similar as much as possible. Also dissolution behaviour studies of preoxidised LWR UO2 and MOX spent fuel up to different on the oxidation degree. For both fuel types, UO2 and MOX, the fission products considered showed a fractional release normalised to uranium higher than 1, due to either the larger inventory at preferential leaching zones, such as, grain boundaries or to the inherent higher solubility of some of these elements. In contrast to fission products, the fractional release of PU from the UO2 fuel was not affected by the oxidation level. Finally a thermodynamic study of the experimental leaching results obtained in this work was performed. (Author)