Hybrids for Direct Enrichment and Self-Protected Fissile Fuel Production

For hybrid reactors that would directly enrich light water reactor fuel bundles with ²³⁹Pu, the fuel distribution across a bundle can be made to be more uniform than when ²³³U is produced from thorium. As expected, more fuel is produced from ²³⁸U than from ²³²Th per fusion event, although the fuel production per unit thermal power can be greater in the thorium-uranium cycle. The hybrid can be used to produce fissile fuel at a secure fuel production, reprocessing, and fabrication facility. The high support ratio of the hybrid would then allow 10 to 80 external fission reactors to be supported per secure site, depending on the conversion ratio of the off-site fission reactors. It is found that fuel to be shipped away from a secure site can be rendered resistant to diversion by irradiation to a burnup of 0.4 MWd/t in a low power fission reactor on-site.