Liquid metal cooling issues for fusion and fission

Liquid metal application to nuclear power plants was initiated in a design of fast reactors with using sodium or lead bismuth eutectic, and developed into a sodium fast breeder reactor and lead bismuth fast reactor. In the development stage, Na and NaK were carefully compared and the former was chosen. In the nuclear fusion application, liquid metals of Li or LiPb will be used as a coolant and tritium breeder. A nuclear reactor requires two materials of moderator and coolant. Water or sodium satisfies double duty, leading to the oligopoly situation by LWR or Na-FBR. The success of these reactors depends on the selection of coolant material that works as a moderator. On an analogy of this history, fusion power plant should be integrated to employ a coolant that works as tritium breeder, such as Li or LiPb. Technology progresses in the system design are introduced, which will have synergy effect for fusion.