Sustainable Energy

A Look Back at Three Mile Island

The presidential commission investigating the Three Mile Island accident learned that the problems rested with people, not technology.

Nov 6, 2009
March 29 of this year marked the 30th anniversary of the meltdown at the second of two reactors built at Three Mile Island. Metropolitan Edison began construction of the Three Mile Island nuclear generating station in the 1960s. The first unit went online in 1974 and TMI-2 followed four years later.
Located just south of Harrisburg, PA on a long, thin island in the Susquehanna River the reactor facility is surrounded by small towns and farmland. In this aerial view taken two weeks after the accident, TMI-2 and its two cooling towers are towards the bottom.
The large cooling towers at Three Mile Island came to symbolize the accident but contrary to popular belief the towers were not the source of the radioactivity released from the facility during the accident.
A Nuclear Regulatory Commission inspector looks at meters in the control room at TMI-2. An overloaded alarm system was partially to blame for the Met-Ed technicians’ failure to prevent a minor malfunction–a stuck relief valve–from turning into a major disaster.
Officials nearly ordered a complete evacuation of the areas around Three Mile Island but ultimately decided against it. Here, a local resident is shown with the thermoluminescent dosimeters (TLDs) used to measure radiation exposure in the surrounding towns.
The accident at TMI provoked near-panic throughout the nation, prompting President Jimmy Carter to visit the site three days after the crisis began. The presidential motorcade is here seen leaving the area following the inspection.
Protestors rally at the Pennsylvania Capitol shortly after the accident. The accident at TMI energized an already growing anti-nuclear movement.
President Carter followed by John Kemeny, whom Carter appointed to head the commission investigating the accident. Kemeny was a noted computer scientist (he codeveloped the BASIC programming language) and administrator (he was then president of Dartmouth College), but had no particular background in nuclear power and admitted in his essay for TR that the appointment surprised no one more than himself.