Measurements of irradiation creep strain in silicon carbide irradiated with silicon ions

The significant internal share stress through the differential swelling will be introduced in the thick structures of nuclear reactors by the tans-thickness temperature gradient. In this work, the irradiation creep in SiC, which is indispensable to mitigate the internal stress, was studied by using ion-irradiation. High purity CVD SiC samples mechanically thinned to 50, 75, and 100 μm were firmly fixed on the curved irradiation base and the tensioned surfaces were irradiated to 0.01-3 dpa at 400, 600, and 800°C. The initial applied stresses at the surface were 150, 225, and 300 MPa, respectively, depending on the sample thickness. The creep strain was estimated from the sample curvature based on comparison with the curvature of sample irradiated under non-stressed condition. Creep strain were strongly dependent on both the applied stress and irradiation temperature, where the approximate linear relationship with swelling rates measured for non-stressed SiC was found for all the irradiation temperatures. Creep strains were also linearly dependent on the applied stress with temperature dependent proportionality constants.