Oxidation of Silicon Carbide Composites for Nuclear Applications at Very High Temperatures in Steam

Single-rod oxidation and quench experiments at very high temperatures in steam atmosphere were conducted with advanced, nuclear grade SiCf/SiC CMC cladding tube segments. A transient experiment was performed until severe local degradation of the sample maximum temperature approximately 1845 °C. The caused by complete consumption external CVD-SiC sealcoat, resulting access to fiber–matrix composite less corrosion resistance. Approaching these accompanied accelerated gas release mainly H2 CO2, formation surface bubbles white smoke. Three one-hour isothermal tests 1700 °C final water flooding one three-hour fast cool-down Ar run under nominally identical conditions. All isothermally tested samples survived without any macroscopic degradation. mechanical performance quenched clad segments not significantly affected, while maintaining a capability tolerate damages. Despite harsh exposure conditions, load transfer between SiC fibers matrix remained efficient, allowing composites accommodate deformation.