The nuclear fuel cycle

An overview of nuclear fuel cycle technology is presented. The process of uranium-plutonium fuel cycle is shown with a flow chart from uranium mining through conversion, enrichment, fuel fabrication, irradiated fuel storage, fuel reprocessing including mixed UO2-PuO2 reprocessing for fast breeder reactors to waste storage. The uranium resources reasonably assured at the cost under $80/kgU, and the uranium annual production in 1978 in principal countries are tabulated. The technical issues are outlined for each item of uranium minerals and mining, uranium milling, uranium purification, natural uranium conversion including conventional uranium refining processes and Allied Chemical UF6 process, uranium enrichment technologies such as gaseous diffusion, gas centrifuge, separation nozzle process, South African process, French Chemex process and three advanced processes developed by USDOE, namely atomic vapor laser isotope separation process (AVLIS), molecular laser isotope separation process (MLIS) and plasma separation process, conversion of UF6 to UO2, fuel fabrication, irradiation in converter reactor, irradiated fuel storage and reprocessing by purex process. The fast breeder fuel cycle constitutes a feature of handling mixed dioxide with burn-up from 60,000 to 100,000 megawatt-days per ton and depleted uranium dioxide. The waste processing and waste storage are outlined for vitrification and Joule-heated ceramic process. (Nakai, Y.)