Neutron Irradiation Swelling of SiC and SiCf/SiC for Advanced Nuclear Applications

Silicon carbide (SiC) is used as a layer in TRISO fuel of high temperature gas-cooled reactors because of its excellent thermal and mechanical properties. SiC fiber-reinforced SiC composites (SiCf/SiC) are also a candidate material for structural material for fusion reactor blanket and cladding materials of advance fission reactors. In this research, seven of monolithic SiC or SiCf/SiC composites materials with different fabrication processes were irradiated in the BR2 reactor up to a fluence of 2.0-2.5×1024 (E>0.1 MeV) at 333-363 K. Changes in macroscopic lengths and lattice parameters before and after the neutron irradiation were measured. Furthermore, microstructure of SiCf/SiC composites was investigated using a scanning electron microscope, too. Results showed that after the neutron irradiation, the group of SiC and SiCf/SiC composites were swelled approximately 1.24∼1.33% and 1.00∼1.19% in length, respectively. Apparently the presence of fibers resulted in smaller swelling. It may be attributed for smaller swelling of SiC fibers. Further difference in swelling may be caused by the presence of different sintering additives.