The safe disposal of actinide wasteform materials will require a predictive model based on a mechanistic understanding of the effects of such radiation damage on the composition, structure, microstructure and corrosion resistance of ceramic wasteforms, over geological timescales. Defect accumulation and cascade overlap eventually result in amorphisation of the initially crystalline host material, akin to metamictisation of natural U and Th bearing minerals. Here we develop a systematic methodology to probe the structure and evolution of the radiation damaged structure of model wasteform materials, combining ex-situ ion beam irradiation of bulk ceramics with X-ray Absorption Spectroscopy to quantify damage induced changes in element speciation. Crucially, we demonstrate that the application of XAS in grazing angle geometry is essential to determine element specific local structure in ion beam damaged surface, in isolation of the undamaged substrate.

Structure of ion beam amorphised titantate ceramics for actinide disposition studied by grazing angle X-ray absorption spectroscopy

243rd National Meeting (2012)

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