Word: fusion
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Dates: during 1970-1979
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...somewhat closer to reality than most people realize. In laboratories in the U.S., the Soviet Union, Western Europe and Japan, scientists are involved in a spirited competition to become the first to achieve one of the most important-and difficult-goals ever sought by man: the harnessing of nuclear fusion. If that goal is reached, the world may never again be faced with an energy crisis...
Invisible Springs. Compared with the difficulties of controlling fusion, producing energy from nuclear fission is relatively simple. In fission-which occurs in A-bomb explosions and powers today's nuclear plants-a speeding neutron is used to split the atomic nucleus of a heavy element like uranium into the nuclei of one or more lighter elements. In the process, more neutrons are given off. But the mass of the resulting nuclei and neutrons is somewhat less than the mass of the original nucleus; the missing matter-as predicted by the famed Einstein equation E=mc2-has been converted into...
...nuclear fusion-the process that feeds the fires of the sun and gives the H-bomb its awesome power-atomic nuclei of light elements like hydrogen collide and merge. The resulting nuclear particles contain less mass than the sum of the original nuclei; again, matter has been converted into energy. But while atomic nuclei easily split, they do not easily fuse; they have positive electric charges and thus repel each other, acting as if they had invisible springs between them. Getting them to join requires that they approach each other with enough energy to overcome their natural repulsion and smash...
These conditions exist, more or less, in the sun and other stars, where the tremendous gravitational forces of the giant bodies, combined with their huge amounts of hydrogen, produce self-sustaining fusion reactions. But producing controlled fusion on earth is a far more difficult task-and to do it practically and economically may well be the most complicated technological venture ever attempted. Says Physicist Gerald Yonas of New Mexico's Sandia Laboratories, a federally supported atomic research facility: "It's the most exciting area today in science. Fusion power is a mountain we have to climb...
...first steps on that ascent was the realization that the conditions of temperature and density necessary for the sustained fusion of ordinary hydrogen nuclei were far beyond the present capabilities of science. But experiments showed that it was easier to fuse two isotopes, or different forms, of hydrogen: deuterium and tritium. Reason: the nuclei of these isotopes have larger cross sections than those of ordinary hydrogen nuclei. Thus the probability of direct collisions between them is increased and that in turn means that less extreme conditions are required to make them fuse. The easiest fusion to attain, scientists determined...