[填空题]Our demand for electricity is climbing so fast that over the next decade U.S. generating capacity must increase by a third. Fossil fuels supply nearly three-quarters of this energy. But the smoke-belching stacks of coal-fired, gas-fired and oil-fired plants are also responsible for about half of our air pollution.
That, we used to think, is a small price to pay for progress. But there is an alternative, one that produces no smoke and can actually create more fuel than it consumes. In many regions it is even cheaper than coal-fired electricity: nuclear power.
Already nuclear power is the second largest source of our electricity, and a new family of "failsafe" nuclear reactors — some now under construction in Japan — may one day make nuclear power even cheaper and more plentiful.
The only major difference between nuclear and conventional plants is that nuclear fuel is far more radioactive. For this reason, the core must be sealed from the outside environment — and so