Oxygen Diffusion and Electrical Conductivity Measurements in Uranium Dioxide

International audienceIn this paper, we describe two experimental set-ups which enable the measurement of electrical properties and intrinsic diffusion coefficients in UO 2. Electrical conductivity measurements are insured by a standard four point Kelvin-Bridge method. In parallel, the gas-solid isotopic exchange method is used to load the samples with 18O tracer atoms, the concentration profile of which are subsequently characterized using SIMS and chromatic confocal microscopy. An application of both types of measurements on a UO 2 single crystal is given. The diffusion study was carried out at 750degC, and the electrical conductivity study was performed between 1000degC and 1300degC at oxygen potentials at which the material exhibits extrinsic behaviour. We show how a careful use of both measurements in conjunction can be an indication of the operative migration mechanism