Forget Three Mile Island, Chernobyl, and Homer Simpson. Nuclear energy is now being touted as a greenhouse-gas free solution to global warming. But one big problem remains: What to do with untold tons of radioactive waste that will be red-hot for hundreds of thousands of years? The answer: Recycle it. But not with current technology, which leaves behind an unfortunate by-product - weapons-grade plutonium. Instead, U.S. government scientists are devising a chemical technology called Urex that allows four times as much waste to be packed into nuclear burial grounds. The technology encases the plutonium in other elements, rendering it all but useless to terrorists, North Korean dictators, and other evildoers. (See the full story.)