In recent years, FCIs made of ceramic materials such as silicon carbide composite (SiC/SiC) have been proposed for both electrical and thermal insulation between the liquid breeder and the channel walls. Although the electrical resistivity of SiC/SiC is lower than that of the candidate insulator coating materials, the use of an insert that is much thicker than the coating allows for sufficient reduction of induced electrical currents.

An FCI is attractive for application to dual­coolant Li-Pb blanket concepts in which heat is removed by both a high flow rate of He and Li-Pb.41,42 This concept, however, may not be applied to self-cooled liquid metal blankets because these blankets need to avoid thermal insulation between the coolant and the first wall or the blanket structural components and coolants.