New applications for high-power proton linacs

Advances in high-current rf proton linac technology have made it possible to project credible designs for a new generation of very intense spallation neutron sources for nuclear process applications. Current interest is focused on transmutation of nuclear waste and tritium production. Accelerator production of tritium was proposed recently as a contingency backup to the reactor approach. The concept is based on a 250-mA, 1.6-GeV cw proton beam incident on a matrix of lead (Pb) and lithium-aluminum (Li-Al) rods. Neutrons produced in the Pb are absorbed in lithium to produce tritium. A review by the Energy Research Advisor, Board (ERAB) affirmed the technical feasibility of the accelerator concept. This finding stimulated investigation of alternate target/blanket concepts, leading to a separated-function scheme that produces tritium through neutron capture on 3He in a thermal flux level > 1016 n/cm2-s. The potential of such high thermal neutron intensities opens an exciting range of new approaches to accelerator transmutation of long-lived actinides and fission products, and to the possibility of reducing time scales for eliminating such wastes from > 104 years to human lifespans