New insight into delta-Pu alloy oxidation kinetics highlighted by using in-situ X-ray diffraction coupled with an original Rietveld refinement method

The reactivity of a delta-Pu alloy was studies under dry oxygen at different temperatures. Phase analysis has shown the presence of alpha-and beta-Pu2O3, PuO2, as well as the destabilisation of the delta-phase. The oxidation kinetics were studied using in-situ X-ray diffraction cm pled with an original method of Rietveld refinement enabling an individual monitoring of the growth of each oxide. The results have evidenced a parabolic stage resulting from the thickening of the alpha-Pu2O3 layer, in which a compressive stress state develops. This stage is followed by the linear growth of a porous PuO2 scale.