The authors consider a symbiotic fusion and fission reactor system which ensures the breeding of nuclear fuel. In the blanket of the fusion reactor, 233U is produced from thorium circulating in the form of ThF4 in a mixture of sodium and beryllium fluoride melts. The molten-salt fission reactor burns the 233U and produces, for the fusion reactor, tritium from lithium circulating through its core in the form of LiF mixed with BeF2 and 233UF4. If the ratio of the thermal capacities of the fusion and the fission reactor is 1 : 11, the system will generate electric power and breed fuel with a doubling time of 4–5 years.The system has the following special features:1. Much simpler and cheaper fuel reprocessing than with present fission reactors. Reprocessing consists merelyof constantly removing 233U from the salt circulating in the fusion reactor blanket by fluorination andremoving xenon from the fuel salt of the molten-salt reactor by gas purging. The fuel salt of the molten-saltreactor is renewed periodically and the 233U extracted from it.2. Tritium production takes place in the fission reactor, which is a simpler system than the fusion reactor.3. The fusion reactor blanket is almost "clean": tritium is not produced in it and the fission fragmentactivity does not exceed the activity induced in the structural materials.4. Virtually all the thorium in the fusion reactor blanket can be used for producing 233U.
Membrane separation technologies: their application to the fusion reactor fuel cycle