Research of radiation damage accumulation on SiC/SiC composites for reactor core components of gas cooled fast reactor using ion irradiation technique

Recent progress of research for silicon carbide (SiC) materials has established a high quality SiC/SiC composite. Nano-powder Infiltration and Transient Eutectic Phase (NITE) process is able to fabricate SiC composites having highly dense matrix. For the research of microstructural stability of NITE SiC/SiC composite against radiation damages, ion irradiation experiments were brought about using DuET facility at Institute of Advanced Energy, Kyoto University. The reductions of mechanical and dimensional properties under irradiation environments are closely correlates with the microstructural evolutions by irradiation, thus it is important to precise analysis of microstructural construction and composition on SiC/SiC composite. In this research, an ion irradiation method and TEM investigation were used for the research. The ion-irradiation experiments were performed using a 1.7 MeV tandem accelerator. The irradiation temperature and the damage rate were up to 1200°C and 10 dpa, respectively. TEM investigations revealed that the SiC matrix made by NITE processing was dense and stoichiometric. TEM investigation shows SiC matrix was crystallized very well and there were a little secondary phase. The EDX analysis specified the secondary phase was aluminum-rich, it is supposed to be oxides of elements included in additives. The SiC grains and the secondly phase showed enough microstructural and dimensional stabilities after the irradiation at 1200°C and 10 dpa. The stabilities of NITE SiC/SiC composites under irradiation environments were confirmed.