blanket is the structure surrounding a fusion plasma that absorbs the neutrons escaping the reaction, converts their energy into useful heat, and — when it contains lithium — breeds new tritium fuel.
The blanket is often confused with the 📝first wall, its nearest neighbor: the first wall is the thin armored surface directly facing the 📝plasma, bearing its radiation and particle flux, while the blanket is the thick structure behind it that does the volumetric work. In a 📝D-T reaction, roughly 80 percent of the released energy leaves as 14 MeV neutrons, which carry no charge and pass straight through the confining magnetic field; the blanket is where that energy finally lands, turning neutron kinetic energy into heat that can raise steam and drive a turbine. The blanket also shields the magnets and outer structure from neutron damage.
A blanket containing lithium performs a third function: neutron capture splits the lithium into helium and 📝tritium, letting a power plant breed the fuel it burns — the breeding blanket variant. Designs span ITER's solid, water-cooled shield modules to liquid concepts in which a molten salt or liquid metal serves as coolant, breeder, and shield at once. Because no machine has yet operated a full breeding blanket at power-plant conditions, the blanket remains one of the least demonstrated systems in 📝fusion engineering.