On March 28, 1979, one of the worst accidents in the history
of the U.S. nuclear power industry began when a pressure
valve in the Unit-2 reactor at Three Mile Island fails to close.

Cooling water, contaminated with radiation, drained from the
open valve into adjoining buildings, and the core began to
dangerously overheat.

The unharmed Unit-1 reactor at Three Mile Island, which was s
hut down during the crisis, did not resume operation until 1985.

Cleanup continued on Unit-2 until 1990, but it was too damaged
to be rendered usable again.        
    

President Jimmy Carter, second from left, visits the nuclear
plant near Harrisburg, Pa., USA, April 4, 1979.