Diffusion in ceramic oxide systems

Recent results on diffusion processes in oxide systems are reviewed, covering aspects of self-diffusion, chemical diffusion, thermodiffusion, and impurity diffusion. The guideline for selecting the oxide systems was either their basic scientific interest or their technological importance. For the latter, nuclear technology (mainly oxide fuels for fission reactors, with a few examples of oxides for fusion breeder blankets) is emphasized, whereas for the former oxides are selected as examples for which diffusion measurements yield interesting results for better understanding of point defect behavior, defect clustering, phase changes, deviations from stoichiometry, or processes such as creep. Two particular phenomena are treated in some detail: diffusion of volatile fission products in UO/sub 2/ nuclear fuel and diffusion processes of relevance to long-term safe storage of radioactive waste in the form of glasses