The unfolding multiple nuclear reactor catastrophe in Japan is prompting overdue attention to the 104 nuclear plants in the United States-many of them aging, many of them near earthquake faults, some on the west coast exposed to potential tsunamis.

Nuclear power plants boil water to produce steam to turn turbines that generate electricity. Nuclear power’s overly complex fuel cycle begins with uranium mines and ends with deadly radioactive wastes for which there still are no permanent storage facilities to contain them for tens of thousands of years.

Atomic power plants generate 20 percent of the nation’s electricity. Over forty years ago, the industry’s promoter and regulator, the Atomic Energy Commission estimated that a full nuclear meltdown could contaminate an area ‘the size of Pennsylvania