Three Mile Island, Where U.S. Dodged Its Own Chernobyl, to Close

It started with a pump failure early on the morning of March 28, 1979. Steam generators were unable to draw heat out of a reactor at the Three Mile Island nuclear power plant in Middletown, Pa. While an emergency shutdown was triggered, another problem—a stuck valve—was letting coolant escape from the reactor core.

The core’s fuel began to overheat, causing the partial meltdown and release of radiation that remains the worst nuclear accident in U.S. history. The reactor, one of two at the plant, has been silent ever since. To this day, it stands as an enduring symbol of all ...