This not only greatly reduces the size of the reactor, but the fast neutrons from a single reaction are capable of causing several breeding reactions. By surrounding the core with additional fertile material such as natural uranium, or even nuclear waste from other reactors, the breeding reaction will take place in a larger volume and in otherwise useless materials. This section is known as the "blanket". Such a design also has the quality that it generates more fuel than it consumes, as long as the "breeding ratio" is greater than 1.