Ceramic/ceramic composites, in particular, SiC/SiC composites, offer two major advantages over conventional structural metals for fusion applications; i.e., low activation under neutron irradiation and high temperature mechanical properties. These composites face several challenging issues which include: fabrication scale up, joining methods, and chemical compatibility. Inherent porosity, together with microcracking that occurs during stressing beyond the yield strength may negate the consideration of these composites for hermetic boundaries unless combined with other materials. Irradiation stability is an issue until better data can be obtained. Hence, the feasibility of using these composites in a fusion structure remains to be established.