Abstract :
Presently discernible limitations to the extent of low-cost uranium resources provide an obvious incentive for seeking better utilization of fissile material, which may well become dominating by the end of the century. The high degree of world interest in breeder reactors, which could produce more fissile material than they consume, is thus very understandable, for the substantial conversion of fertile into fissile material thereby offered would greatly increase the effective energy yield of the mined fuel. However, the large-scale use of fast breeders which would be necessary for substantial impact on resource conservation would also require that these reactors be entirely acceptable also in other ways. Particularly they would have to compete with other routes to nuclear power in areas of capital cost, maintainability, and siting flexibility. Such considerations have stimulated the evolution of the gas-cooled fast breeder and the contemplation of combinations of fast breeders and advanced high temperature converter reactors aimed at taking best advantage of the special merits of each type. Predominant influences here are the enhanced importance of breeding ratio to the effectiveness of such a combination, the special worth of U233 as a thermal reactor fuel and the value of the high temperature capability, both directly and as a factor broadening the options available to power plant design.
