Thermo-mechanical simulations of laser heating experiments on UO2

Abstract In this paper, a thermo-mechanical model suitable for the interpretation of laser heating experiments simulating the power increasing phase of a RIA transient on UO 2 samples is detailed. The thermal model includes a description of the heat deposition on the sample surface and of the heat transfer within the thickness and radius of the UO 2 sample. The mechanical model describes cracking and crushing of the material depending on the loading mode (tension or compression dominated) and on temperature. The brittle - ductile transition in compression is in particular well reproduced. The parameters fitting is based on available uniaxial compression tests performed at high strain rates and on bending tests performed at moderate strain rates. The application of the mechanical model to annular laser heating experiments led to a good estimation of the crushing and cracking location (near the sample periphery), of the crack orientation (circumferential) and of the beginning of cracking.