High Power Accelerators for Spallation Breeders of Fissile Material

The accelerator requirements for an economic spallation breeder system are reviewed. An intermediate energy, high mean current proton linear accelerator is the preferred choice. Present designs of drift tube and coupled cavity structures can be adapted to 100% duty factor operation. From recent work on meson factory and synchrotron injector linacs it appears likely that beam spill can be reduced to acceptable levels. For economy the emphasis is on the efficient production of radiofrequency power, most of which must be delivered to the accelerated beam. Some trends in current development are outlined.