Thermal diffusivity measurements on UO$_2$ fuels with the flash method

International audience; Thermal conductivity of the nuclear fuel :-A key parameter to understand the performance of the fuel under irradiation-Highly dependent on microstructure, porosity and its distribution -Influences almost all important processes such as fission gas release, swellingKnowledge of the nuclear fuel thermal conductivity (derived from a thermal diffusivity measurement):- A fundamental data for a better prediction of fuel performance in reactor - Must be measured accurately (including a reliable uncertainty assessment