The authors would like to acknowledge the funding from the projects supported by the Natural Science Foundation of Hunan Province (no. 2020JJ3487),e Research Foundation of Education Bureau of Hunan Province (no. 18C0450),e Opening Project of Cooperative Innovation Center for Nuclear Fuel Cycle Technology and Equipment (no. 2019KFY22), and College Students' Innovation and Entrepreneurship Training Program of Hunan Province (no. s201910555095).
In a high-temperature gas-cooled reactor, the integrity of tristructural-isotropic-(TRISO-) coated fuel particles ensures the safety of the reactor, especially in case of an air-ingress accident. The oxidation of TRISO particles with the outer layers of silicon carbide (SiC) was performed at temperatures of 900°C–1400°C in air environment. Both the microstructure and phase composition of the SiC layers were studied. The results showed that the SiC layers had a good oxidation resistance below 1100°C. However, the amorphous silica on the SiC layers formed at 1200°C and gradually crystallized at 1400°C with the presence of microcracks. The reaction rates of the SiC layers were determined by measuring the silica thickness. It was proposed that the oxidation of the SiC layers followed the linear-parabolic law with the activation energy of 146 ± 5 kJ/mol. The rate-determining step of the oxidation was the diffusion of oxygen in silica. Natural Science Foundation of Hunan Province 2020JJ3487 The Research Foundation of Education Bureau of Hunan Province 18C0450 The Opening Project of Cooperative Innovation Center for Nuclear Fuel Cycle Technology and Equipment 2019KFY22 College Students’ Innovation and Entrepreneurship Training Program of Hunan Province s201910555095
