Technological problems and the future of research on the basic properties of actinide oxides

Current research on the properties of (U,Pu)O2 fuels and other actinide oxides is placed in the context of the requirements of the nuclear industry. Examples are given of how an understanding of the underlying processes can assist in solving the problems in the nuclear fuel cycle. The roles of solid-state diffusion and vapour transport in the restructuring of nuclear fuels are examined and the importance of defining the chemical state of the fuel is demonstrated. Surface and grain-boundary properties are identified as neglected research topics and their significance with respect to fission gas and volatile fission product behaviour is shown. A brief discussion of the requirements of severe accident analysis is given and the paper concludes by speculating on the most likely future requirements. (author)