Three Mile Island accident
Overview
The Three Mile Island accident was a core
meltdown
in Unit 2 (a pressurized water reactor
manufactured by Babcock & Wilcox
) of the Three Mile Island Nuclear Generating Station
in Dauphin County, Pennsylvania
near Harrisburg
, United States
in 1979.
The power plant was owned and operated by General Public Utilities and Metropolitan Edison (Met Ed). It resulted in the release of approximately 2.5 million curie
s of radioactive gases, and approximately 15 curies of iodine-131
.
The accident began at 4 a.m.
Nuclear reactor core
A nuclear reactor core is the portion of a nuclear reactor containing the nuclear fuel components where the nuclear reactions take place.- Description :...
meltdown
Nuclear meltdown
Nuclear meltdown is an informal term for a severe nuclear reactor accident that results in core damage from overheating. The term is not officially defined by the International Atomic Energy Agency or by the U.S. Nuclear Regulatory Commission...
in Unit 2 (a pressurized water reactor
Pressurized water reactor
Pressurized water reactors constitute a large majority of all western nuclear power plants and are one of three types of light water reactor , the other types being boiling water reactors and supercritical water reactors...
manufactured by Babcock & Wilcox
Babcock and Wilcox
The Babcock & Wilcox Company is a U.S.-based company that provides design, engineering, manufacturing, construction and facilities management services to nuclear, renewable, fossil power, industrial and government customers worldwide. B&W's boilers supply more than 300,000 megawatts of installed...
) of the Three Mile Island Nuclear Generating Station
Three Mile Island Nuclear Generating Station
Three Mile Island Nuclear Generating Station is a civilian nuclear power plant located on Three Mile Island in the Susquehanna River, south of Harrisburg, Pennsylvania. It has two separate units, known as TMI-1 and TMI-2...
in Dauphin County, Pennsylvania
Dauphin County, Pennsylvania
Dauphin County is a county in the U.S. state of Pennsylvania and is one of the three counties comprising the Harrisburg–Carlisle Metropolitan Statistical Area. As of 2010 census, the population was 268,100. The county includes the city of Harrisburg, which has served as the state capital...
near Harrisburg
Harrisburg, Pennsylvania
Harrisburg is the capital of Pennsylvania. As of the 2010 census, the city had a population of 49,528, making it the ninth largest city in Pennsylvania...
, United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
in 1979.
The power plant was owned and operated by General Public Utilities and Metropolitan Edison (Met Ed). It resulted in the release of approximately 2.5 million curie
Curie
The curie is a unit of radioactivity, defined asThis is roughly the activity of 1 gram of the radium isotope 226Ra, a substance studied by the pioneers of radiology, Marie and Pierre Curie, for whom the unit was named. In addition to the curie, activity can be measured using an SI derived unit,...
s of radioactive gases, and approximately 15 curies of iodine-131
Iodine-131
Iodine-131 , also called radioiodine , is an important radioisotope of iodine. It has a radioactive decay half-life of about eight days. Its uses are mostly medical and pharmaceutical...
.
The accident began at 4 a.m.
