Tokamak - Tokamak Cooling

Tokamak Cooling

The fusion reactions in the plasma spiraling around a tokamak reactor produce large amounts of high energy neutrons. These neutrons, being electrically neutral, are no longer held in the stream of plasma by the toroidal magnets and continue until stopped by the inside wall of the tokamak. This is a large advantage of tokamak reactors since these freed neutrons provide a simple way to extract heat from the plasma stream; this is how the fusion reactor generates usable energy. The inside wall of the tokamak must be cooled because these neutrons yield enough energy to melt the walls of the reactor. A cryogenic system is used to prevent heat loss from the superconducting magnets. Mostly liquid helium and liquid nitrogen are used as refrigerants. Ceramic plates specifically designed to withstand high temperatures are also placed on the inside reactor wall to protect the magnets and reactor.