Timeline

December 31, 1978:

Unit 2 of Metropolitan Edison Company’s nuclear generating plant at Three Mile Island (TMI) on the Susquehanna River. Continue...


March 28, 1979 Day 1:

4:00 AM: Due to equipment failure and operator error, a partial nuclear core meltdown of the TMI’s Unit 2 reactor. Continue...


March 29, Day 2:

Plant officials were still attempting to fully assess the damage to the plant. Continue...


March 30, Day 3:

A "bubble" in the reactor vessel that led to some venting of radioactive material and garbled communications. Continue...


March 31, Day 4:

A false rumor that a "bubble" that had formed in the reactor potentially could explode. Continue...


April 1, Day 5:

With television news in tow, President Jimmy Carter and Governor Richard Thornburgh visited the control room of the plant. Continue...


April 6, Day 10:

Operators having regained control of the plant, Governor Thornburgh lifted the evacuation advisory and declared the Three Mile Island "crisis had passed." The cleanup would take years.


October 25, 1979:

The Nuclear Regulatory Commission recommended the maximum fine permitted under law for Metropolitan Edison’s violations that contributed to the accident.


Ocotber 30, 1979:

The Presidential Commission (Kemeny Commission) issued its report. Continue...


1980:

For their coverage of the Three Mile Island accident, the staff of the Philadelphia Inquirer was awarded the Pulitzer Prize. Continue...


June/July 1980:

In preparation for entry into the reactor building venting of radioactive gasses proceeded over an eleven day period. Continue...


July 23, 1980:

The first person since the partial reactor core meltdown entered the TMI-2 reactor building. Continue...


October 15, 1980:

The Nuclear Regulatory Commission begins hearings on whether or not to restart Unit 1, which has be idle since July of 1979.


November 1980:

First meeting of an Advisory Panel for the Decontamination of TMI-2. State and local officials, scientists, and citizens are represented.


July 1981:

Governor Thornburgh proposed a one billion dollar cost-sharing plan to clean up the accident that required a partnership of state and federal governments and the nuclear industry.


May 18, 1982:

Central Pennsylvania voters in three counties voted to oppose the restart of Three Mile Island Unit 1. Continue...


July 1982:

Underwater camera surveys the inside of the reactor vessel for the first time, revealing that the extent of the core meltdown was far greater than expected. Continue..


October 1985:

Removal of damaged core of the Unit 2 reactor began. Continue...


July 1986:

Shipment of reactor core debris to an off-site storage facility began. Continue...


January 1991-August. 1993:

Processing of 2.23 million gallons of accident-generated water was completed. Continue...


Although a number of studies done by a variety of investigators have concluded that the accident did not impact the health of area residents, this issue is still debated. Continue...