Structural investigation of self-irradiation damaged AmO2

Studying self-irradiated materials is an ideal means to investigate the effect of the damages on material structure and to better understand the behaviour of irradiated nuclear fuels. In this context, X-ray diffraction, X-ray absorption spectroscopy and transmission electron microscopy have been used to investigate self-irradiation damaged AmO2. Combining these techniques allows studying the microstructure and the variation of the fluorite structure at both short-range and long-range order. Thus, the increase of both interatomic distances and lattice parameter was shown, as well as the presence of nanometer sized He bubbles. As confirmed by the observed high-level of crytallinity, the fluorite structure exhibits a high radiation tolerance, which is confirmed by the low increase of the lattice parameter. This could be explained by a self-annealing mechanism of the created defects at room temperature.JRC.E.4-Nuclear fuel