PHOTOS: A look back at the Three Mile Island nuclear plant accident

A cooling tower of the Three Mile Island nuclear power plant near Harrisburg, Pa., looms behind an abandoned playground, March 30, 1979. (AP Photo/Barry Thumma)

This was the scene in Goldsboro, Pa., on March 31, 1979, three days after the nuclear accident at the Three Mile Island nuclear facility in Middletown, Pa. Most people in the area following the nuclear accident either evacuated or stayed indoors. In the background at center is one of the cooling towers of the nuclear facility. March 28, 1999, will be 20th anniversary of the nation's worst nuclear accident. (AP Photo)

Sen. Richard Schweiker, R-Pa., left, and Edward Kennedy, D-Mass., members of a Senate Health and Scientific Research subcommittee, confer during a meeting of the panel Wednesday, April 4, 1979 in Washington. The group is probing the nuclear accident at Three Mile Island nuclear power plant in Pennsylvania. (AP Photo/Charles Harrity)

Pennsylvania Governor Dick Thornburgh, left, announces the closing of schools in the area around the Three Mile Island PWR, on March 30, 1979, in Harrisburg, Pa., after an accident at the nuclear power plant led to the release of radioactive gas from the reactor into the atmosphere. The governor advised the evacuation of small children and pregnant women. Standing at right is Lt. Gov. William Scranton. (AP Photo)

Evacuated women and children sleep on army cots in a sports arena, Saturday, March 31, 1979, in Hershey, Pennsylvania. They left their homes near the Three Mile Island nuclear power plant. (AP Photo/Gene Puskar)

U.S. President Jimmy Carter shown April 1, 1979 in the control room of the Three Mile Island nuclear power plant in Middletown, Pa. Standing with Carter from left: Harold Denton, director of the U.S. Nuclear Agency; PA. Gov. Dick Thornburgh; Rosalyn Carter; and an unidentified control room employee. (AP Photo)

U.S. President Jimmy Carter shown April 1, 1979 in control room of nuclear plant, of the Three Mile Island nuclear plant in Middletown, Pa. Standing with Carter from left: Harold Denton, Director of the U.S. Nuclear Agency; PA. Gov. Dick Thornburgh; an unidentified control room employee. (AP Photo)

A Red Cross volunteer leans over to make sure a youngster has everything he wants for lunch at the evacuation center in Hershey Park, Pa., April 4, 1979. Expectant mothers and preschool children were asked to remain at the center for those who live within a 5-mile radius of the Three Mile Island nuclear plant. (AP Photo/Rusty Kennedy)

Workmen at Nuclear Engineer Co.’s Hanford, Washington site on April 23, 1979 remove lid from canister holding sealed container of low level radio-action waste. The waste was transported to the Hanford waste disposal site from the Three Mile Island Nuclear Power Plant, Unit #1 in Harrisburg, Pennsylvania. (AP Photo/Mason)

A group of tourists have their photograph taken by a family member as they pose with cooling towers from Three Mile Island nuclear power plant near Middletown, Pa., May 11, 1979. (AP Photo/Fred Prouser)

Members of the International Brotherhood of Electrical Workers march in support of nuclear power plants outside the Johnstown War Memorial Arena, May 9, 1979. The annual stockholders' meeting of the General Public Utilities (GPU) is to be held in Johnstown on Wednesday. GPU is the parent company for Metropolitan Edison, the owners of the nuclear plant at Three Mile Island near Harrisburg, Penn. (AP Photo)

A sign on a building in Goldsboro, Penn, with a deserted street and nuclear plant cooling towers in the background was the scene here, March 31, 1979. Many of the residents within a five-mile area have evacuated. (AP Photo/R.C. Greenawalt)

Two mothers along with their children carry signs in front of the State Capitol in Harrisburg, Penn., joining other anti-nuclear power plant demonstrators urging the shut-down of Three Mile Island (TMI) nuclear power plant near Harrisburg, April 8, 1979. The plant had an accident causing radiation to leak into the atmosphere. (AP Photo/Paul Vathis)

Anti-nuclear power plant demonstrators mass on the front steps of the State Capitol in Harrisburg, Penn., April 8, 1979, urging a shut-down of Three Mile Island nuclear power plant. The plant had an accident, causing radiation to leak into the atmosphere. (AP Photo/Paul Vathis)