Elastic strains in polycrystalline UO₂ samples implanted with He: micro Laue diffraction measurements and elastic modeling

Abstract

In the framework of the study of long-term storage of the spent nuclear fuel, polycrystalline UO₂ samples have been implanted with He ions The thin implanted layer, close to the free surface is subjected to elastic stresses which are studied by x-ray diffraction (micro Laue diffraction) and a mechanical modeling A simple expression of the displacement gradient tensor has been evidenced; it concerns only three terms (ε₃, ε₄ and ε₅) which strongly evolve with considered grain orientations. Finally, we show that results obtained with micro diffraction are in very good agreement with conventional x-ray diffraction measurements done in laboratory at macro scale.