Word: fusion
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That doesn't mean, however, that anyone should rush to invest in fusion futures. Impressive as Tokamak's achievement was, the $1.6 billion machine generated only one-eighth as much power as it consumed. The next day the reactor managed to generate more than 5 million watts. But even its eventual goal of 10 million will still be only half of the incoming energy. The experiment is an important milestone, but fusion power is still a long way from being commercially useful...
When scientists began working on fusion half a century ago, they had no idea the process would be so hard. It had been relatively easy to get energy through nuclear fission, the breaking apart of such heavy atoms as uranium. That led to A-bombs and today's nuclear power plants. But fusion -- the forcing together of light atomic nuclei, like those of hydrogen -- can release even more energy. The problem is that hydrogen nuclei carry a positive electric charge, and thus they repel one another; they have to be slammed together with terrific force before they will stick...
...bomb blasts are hardly practical in power plants, and the sun's internal pressure is impossible to duplicate on earth. So fusion scientists put their nuclei in a bottle -- not a physical one, since any contact with the walls would instantly cool the gas and kill the reaction -- but a bottle made of magnetic fields. The researchers would make up for the comparatively low pressure inside by raising the temperature to unheard-of levels. (A competing idea that shows promise uses converging laser beams to compress and ignite a stream of tiny, gas-filled glass pellets...
Confining a gas made of electrically charged atomic nuclei -- a plasma -- has proved to be far more complex than anyone had suspected, and so has heating it. While the first rudimentary fusion reactors were a few feet across and weighed a ton or two, the Tokamak weighs hundreds of tons and fills a gymnasium-size room. A commercial reactor would be much bigger still and with current technology would cost hundreds of billions of dollars...
...main attraction of fusion is the potentially limitless fuel supply. The ideal fuel is not plain hydrogen but the formula used last week: a mixture of deuterium and tritium, two isotopes of hydrogen that have extra neutrons in their nuclei. Even though they're rarer than ordinary hydrogen, scientists estimate that enough of these two isotopes could be extracted from the top 2 in. of water in Lake Erie to match the energy in all the world's oil reserves...