breeding blanket is a 📝blanket containing 📝lithium, designed to produce 📝tritium when struck by 📝fusion neutrons — the system that lets a power plant make its own fuel.
The qualifier is what separates the term from its parent: every breeding blanket is a blanket, but not every blanket breeds. A pure shield blanket — ITER's, for instance — absorbs neutron energy and protects the magnets without producing fuel, and ITER will test breeding only in small dedicated test blanket modules. A power plant cannot afford that abstinence: tritium barely exists in nature, so a commercial machine must breed at least as much as it burns, a condition expressed as a tritium breeding ratio above one. Most designs add a 📝neutron multiplier such as 📝beryllium or lead to supply the neutron surplus the arithmetic demands.
Breeding blanket concepts divide into two families. Solid designs pack lithium ceramic pebbles into cooled beds, from which bred tritium is swept by purge gas. Liquid designs dissolve the breeder in a flowing fluid — lead-lithium eutectic or the molten salt 📝FLiBe — so the same liquid breeds fuel, absorbs heat, and can be processed continuously outside the machine. No breeding blanket has yet operated at power-plant scale, making it one of the defining engineering steps between today's experiments and commercial fusion.