The treatment of spent nuclear fuel is presently performed by the industry using different aqueous chemical processes. Alternative dry processes, using pyrochemical methods, are beginning to receive greater attention due to their potential advantages for more compact reprocessing plant designs, as well as for reduced criticality and radiation dose risks.
Effective transmutation of long-lived fission products and minor actinides will be based in future on multi-recycling of the fuel with very high burn-up and short cooling times, conditions for which pyrochemical methods offer various advantages over traditional aqueous processes. Closed nuclear fuel cycles, considered for the future generation of nuclear reactors, could also benefit from pyrochemical reprocessing methods. Studies of pyrochemical processes have so far been carried out at laboratory level. Much R&D work will still be required in order to upgrade these processes to the level of current industrial aqueous processing.
This publication describes ongoing national programmes, collaborative international activiities, present research needs and future applications for pyrochemical methods, used in the treatment of irradiated nuclear fuel. It will be of particular interest to nuclear scientists involved in the development of advanced fuel cyles.