Modelling of UO2 thermal conductivity: Improvement of the irradiation defects contribution and uncertainty quantification

Thermal conductivity of the fuel is a key parameter to assess the temperatures in nuclear fuel. Several empirical or mechanistic models exist in the literature. The objective of this work is to improve one of the empirical formulation by introducing a kinetic evolution of the irradiation defects density in the irradiated fuel. This evolution is calibrated amongst some dedicated experimental data. An inverse probabilistic method is also applied to quantify the modelling uncertainty of the obtained formulation, considering the scattering and the uncertainty of the experimental database available for both un-irradiated and irradiated materials.