Current status of SiC/SiC composites for nuclear applications

Neutron irradiation effects on SiC/SiC composites are reviewed and properties of SiC/SiC composites required for nuclear applications are discussed. High temperature irradiation effects up to 1600 degrees C, which have not been evaluated by neutron irradiation on high purity SiC, were evaluated using ion irradiation at the DuET facility, Kyoto University. Irradiation effects on swelling and mechanical properties were evaluated, and excellent high temperature irradiation resistance of high purity SiC was revealed. Current status of NITE SiC/SiC composites (SiC/SiC composites fabricated by Nano-powder Infiltration and Transient Eutectic-phase processing), which are expected to be used for nuclear applications, in particular due to highly crystalline matrix formation, is reviewed. The NITE processing was improved for industrial applications. Pilot grade NITE SiC/SiC composites were improved and about 400 MPa tensile strength was obtained. The technique was applied to the fabrication of a tube as dense as a plate. The technique was also applied to joining and coating. Successful joining and coating were accomplished.