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NUCLEAR POWER. At present, 171 nuclear power plants are either in use or in various stages of planning or construction in the U.S. But almost all are conventional water-cooled reactors fueled by uranium 235, a rare isotope of uranium that is becoming increasingly difficult to mine and process economically. To avoid a uranium "crunch," President Nixon has ordered development by the 1980s of a new type of reactor called the fast-breeder, a name derived from its unique capability: during the chain reaction, surplus neutrons from the atoms of U-235 in its core bombard a surrounding blanket of U-238, a much more plentiful but nonfissionable form of uranium, and transmute large amounts of it into plutonium. This fissionable byproduct can then be used as a fuel in other breeders. Thus breeders should be able to stretch existing uranium supplies for several centuries. One big drawback: the fission wastes are highly radioactive and extremely difficult to store.
Most scientists believe that the long-range answer to man's energy needs may lie in thermonuclear fusion. The process that fires the sun and all the other stars, fusion releases enormous amounts of energy—but only small amounts of dangerous radioactivity —through the combination of light atoms of hydrogen to form heavier atoms of helium. The earth's seas contain an almost unlimited store of an isotope of hydrogen especially suitable as fusion fuel: deuterium, or heavy hydrogen.
But controlled fusion, as opposed to the uncontrolled variety in an H-bomb, is extremely difficult to achieve. Not only must the deuterium be confined in a dense plasma, but it also must be heated to temperatures of some hundred million degrees. Even if fusion research is vastly expanded, thermonuclear power will probably not be available as an energy source for decades to come.
Until those alternative technologies can fulfill their promise, however, the U.S. must continue to rely on conventional fuels—and to confront the problems that their procurement and use entail. As the environmental movement demonstrated, how fast and effectively the nation faces up to those problems depends largely on public awareness that an energy crisis exists; it was only after the air and waters had become dangerously polluted that the public awoke and demanded the steps that are now gradually beginning to turn the tide of pollution. The U.S. may have even less time to make important decisions about energy. When the gas tanks run dry and the lights begin to blink out, it will be too late.