Twenty-five years after Three Mile Island’s near-meltdown stopped the industry cold (not a single U.S. plant has been approved since), nuclear energy is making a serious comeback. This fall, Congress is expected to start funding a $1.1 billion project to build a new breed of nuclear reactor. The design requirements represent a quantum leap: In addition to being safer and less vulnerable to terrorism than current nuclear plants, the new reactor must do double duty-generate electricity and crank out hydrogen, the presumptive automobile fuel of the future.