ADVANCED FISSION REACTOR SYSTEMS 



Functional Area Problems. Opportunities, and Constraints 57 



THE RELATIVE RISKS OF NUCLEAR POWER 



At some future date, light water reactors may come to be 

 regarded as sufficiently less efficient than other alterna- 

 tives to justify shifts toward those advanced modes. Sever- 

 al such alternatives are being studied intensively in order 

 to ensure the existence of the science and technology base 

 for such a change in policy. The High Temperature Gas 

 Reactor, which uses helium rather than water as a core 

 coolant, is particularly attractive in this regard, because it 

 could be used to provide industrial process heat and could 

 also be suited for use in a converter mode with a uranium 

 and thorium mixture rather than pure uranium used as its 

 fuel (ENERGY). 



Although reactors such as the High Temperature Gas 

 Reactor are expected to bum fuel more efficiently than 

 light water reactors, they would still use only a small 

 fraction of the potential energy content of the U.S. ura- 

 nium and thorium supplies. Present estimates of world 

 uranium reserves indicate that light water reactors in the 

 United States would have to begin to be retired around the 

 end of the century unless more advanced systems were 

 near commercialization by then. Converter reactors could 

 stretch out the useful lifetime of nuclear fission as a viable 

 energy source to some degree. However, Fissile Fuel 

 Breeder Reactors, which could convert uranium and thor- 

 ium into fissionable fuel at the same time they produce 

 energy, would increase the effective fissile fuel supply by 

 a factor of 100. Breeder reactors could be used either by 

 themselves or as a source of fuel for light water or high- 

 temperature gas reactors, thus providing utilities with a 

 predictable quantity of and price guarantee for fissile fuel. 

 Uranium and thorium would thereby become sustainable 

 energy resources usable for the indefinite future. The 

 Administration has proposed to continue the work of the 

 Clinch River Liquid Metal Fast Breeder Reactor Facility. 

 Meanwhile, additional, broadly based research and de- 

 velopment efforts aimed at critical technical areas and the 

 development of technical and engineering data that will 

 permit the selection of a breeder system for possible 

 deployment around the turn of the century are proceeding 

 (ENERGY). 



It is almost certain that the advanced nuclear energy 

 option will be actively pursued somewhere, if not in the 

 United States, since few countries are so richly endowed 

 with the fossil fuel reserves that this country enjoys. 

 France plans to demonstrate a large-scale commercial 

 breeder reactor by the end of 1983. and the Soviet Union is 

 making good progress with breeder technology. If either 

 country succeeds in commercializing breeder reactors, 

 there is little doubt that they will move to market both the 

 reactors and reprocessing facilities abroad. France al- 

 ready has a reprocessing and recycling facility, and re- 

 processing is being actively pursued in the United King- 

 dom and Japan (NRC-14). 



Most analysts agree that there are risks associated with all 

 specific future energy options. They disagree, however, 

 about the magnitude of those risks and about their relative 

 acceptability. The nature of the risks to health and the 

 environment from coal and nuclear fission has been well 

 advertised, although there is considerable disagreement 

 about the seriousness of those risks — particularly those 

 associated with nuclear fission. Barring a catastrophic 

 nuclear accident and taking into account probable en- 

 vironmental effects of atmospheric carbon dioxide, the 

 health, safety, and environmental risks associated with 

 coal are probably greater than those associated with nu- 

 clear fission.^ 



There are, in addition, serious risks of a different kind 

 that could result from prematurely curtailing or eliminat- 

 ing either or both the coal or the nuclear option. These 

 include the risk of economic dislocation (and even war- 

 fare) that could result from placing too much faith in a 

 narrow range of options that proved not to be viable. The 

 differing nature of these risks and the fact that neither their 

 future magnitude nor their future acceptability can be 

 assessed at present again recommends for pursuing ener- 

 gy-related research and development across a wide front. 



RENEWABLE RESOURCES 



Renewable energy sources, including direct solar, bio- 

 mass, geothermal, ocean, and wind, presently provide 

 about 6 percent of the U.S. energy supply. For the most 

 promising of these sources, notably solar and biomass, 

 there will be a continuing need to improve the underlying 

 science and technology base before they can make more 

 significant contributions to the total U.S. energy supply. 

 As in the case of other energy sources, the marketplace 

 will determine the pace and direction of their develop- 

 ment. Federal support will focus on developing underly- 

 ing scientific bases. The removal of subsidies for compet- 

 ing petroleum technologies and various tax incentives 

 should create a more favorable climate for capital invest- 

 ments in renewable energy sources, particularly solar 

 sources (ENERGY). 



DIRECT SOLAR ENERGY 



Almost all analysts agree about the ultimate promise of 

 solar energy. Indeed, direct solar energy, along with 

 breeder and possibly fusion reactors, is probably the only 

 available energy option for the very distant future, with 

 synthetic fuels from coal and shale (or biomass) and 

 hydrogen extracted from water used when transportable 

 fuels are needed. Differences of opinion regarding the 

 viability of solar energy focus on when various solar 

 sources are likely to make a significant penetration into 

 the market. Solar energy systems are. however, uniquely 



