A reactor that both produces and consumes fissionable fuel, especially one that creates more fuel than it consumes. The new fissionable material is created by a process known as breeding, in which neutrons from fission are captured in fertile materials.
A nuclear reactor that produces somewhat more fissile material than it consumes. The fissile material is produced both in the reactor's core and when neutrons are captured in fertile material placed around the core (blanket). This process is known as breeding. breeder reactors have not yet reached commercialization, although active research and development programs are being pursued by a number of countries.
A nuclear reactor that produces its own fuel.