by electrical end-use remains constant.* In the past, electricity has tended to displace the direct use of fuels at the point of consumption, and the fraction of total energy demand met by electricity has increased.
How much of this demand for electricity will be met by nuclear power is also uncertain. Nuclear power has a slight economic advantage over coal. This advantage has good prospects for enhancement, but also has some chance of reversal. Prudent utility planners are likely to plan mixed systems of nuclear power and coal, given these contingencies, but the proportion of each can only be guessed. In addition to cost, planners must also consider the reliability of supply, the stability of regulatory requirements, and prospective public policy. Some considerations will favor nuclear power, others, coal.
A major reservation against too great a reliance on nuclear power may arise from uncertain availability of natural uranium, the primary resource for nuclear fuel. The Uranium Resource Group of this study5 concluded in 1977 that not more than 1.8 million tons of minable domestic uranium oxide (U3O8) reserves and probable resources should be considered as a basis for prudent planning. CONAES has revised its own figure to 2.4 million tons, reflecting higher estimates recently published by the U.S. Department of Energy. (Table 5–1, under the section “Availability of Uranium,” sets out the pertinent estimates.) Translating these figures into nuclear power capacity, 2.4 million tons of U3O8 would meet the lifetime fueling requirements of about 400 GWe of installed capacity, assuming the continued use of light water reactors on once-through fuel cycles. The total nuclear capacity in operation, under construction, or planned in the United States in 1979 amounts to 193 GWe.6 According to the Supply and Delivery Panel, the uranium production rates required to reach installed nuclear capacities much above 200 GWe by 2010 would demand a national commitment to uranium resource exploration and extraction.7
Further expansion and continuation of nuclear power could be accommodated if fuel reprocessing were permitted. The industrial position is that expansion much beyond current commitments would not be undertaken unless the durability of nuclear power were confirmed by commitment to a breeder reactor (or to equivalent fuel production systems, such as accelerator breeders, or fusion-fission devices).† Without firm plans for reactor designs to follow light water reactors, or for fuel reprocessing and recycle, nuclear capacity would have to be gradually phased out as reactors were retired, beginning early in the twenty-first century. However, if (as some resource economists believe) considerably more uranium is found as the price rises, then nuclear capacity could be