Conserving uranium without the fast breeder

The theme of this paper is that the fast breeder reactor, with its alleged problems, is not the only way forward for the nuclear power programme. Some alternative schemes are here discussed, and in particular the use of proton accelerators to produce the intense source of neutrons required for breeding, a scheme that hitherto has not been widely discussed, but is considered to be practical, economically viable, and safe. At several laboratories high intensity accelerators are replacing fission reactors as research instruments providing high intensity neutrons. These neutron fluxes can effect fertile-to-fissile conversion and so produce far more energy than they consume. Once breeding has been established in the Th-U cycle the tremendous reserves of Th, not U, are the ultimate constraint, and it may be that this cycle plus the use of accelerators is the nuclear industry's best chance. The design of some high intensity proton accelerators for the purpose is mentioned. (U.K.)