Structural investigation of self-irradiation damaged AmO2

Abstract Studying self-irradiated materials is an ideal means to investigate the effect of the damage on material structure and to better understand the behavior 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 AmO 2 . 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 and dislocation loops. As confirmed by the observed high-level of crystallinity, 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.