Denatured Fuel Cycles for International Safeguards

Fuel cycles are examined that utilize dispersed national reactors fueled with uranium denatured by diluting the fissile uranium with ²³⁸U. Discharged fuel is to be stored or is to be reprocessed in an international center, where the recovered plutonium is to be consumed in a plutonium-burner reactor. Material quantities are calculated for national pressurized water reactors (PWRs) or heavy water reactors (HWRs) exchanging fissile material with international PWRs or liquid-metal fast breeder reactors. The national reactors are fueled with low-enrichment uranium or with denatured uranium and thorium. The plutonium-burner reactors are fueled with plutonium and natural uranium or plutonium and thorium. The greater ratio of power of national reactors to the power of the plutonium-burning reactors occurs for national HWRs fueled with uranium and thorium and for international reactors fueled with plutonium and thorium. The vulnerability of denatured uranium to further enrichment and the complexity of reprocessing, refabrication, and enrichment operations at the international center are analyzed. PWRs and high-temperature gas-cooled reactors fueled with denatured uranium and operating without fuel reprocessing are also considered.