EXPLAINER | Three Mile Island
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Three Mile Island

On March 28th, 1979 the Unit 2 reactor at the The Three Mile Island nuclear power plant near Harrisburg partially melted down. It marked the most serious accident in U.S. commercial nuclear power plant operating history.

The aftermath brought about “sweeping changes involving emergency response planning, reactor operator training, human factors engineering, radiation protection, and many other areas of nuclear power plant operations,” writes the Nuclear Regulatory Commission. “A combination of equipment malfunctions, design-related problems and worker errors led to TMI-2’s partial meltdown and very small off-site releases of radioactivity.”

The plant’s still operational Unit 1 reactor is now owned by Exelon, while the mothballed Unit 2 reactor is owned by FirstEnergy.

In May 2017, Exelon announced it would prematurely shut down the plant in September 2019—15 years before its license expires. The nuclear power industry has had a hard time competing economically amid slowing demand for electricity and a glut of cheap natural gas.

Both New York and Illinois recently agreed to give billions in subsidies to the nuclear industry by essentially broadening the definition of clean power. The states created so-called zero emission credits for their nuclear plants. There’s been a years-long lobbying push to do something similar in Pennsylvania.

In March 2019, Rep. Thomas Mehaffie (R- Dauphin County) introduced HB 11 . He wants to prevent the early closure of Three Mile Island as well as FirstEnergy’s Beaver Valley plant near Pittsburgh, which is scheduled for retirement in 2021.

The bill aims to amend Pennsylvania’s Alternative Energy Portfolio Standard, a 2004 law requiring electric utilities to buy parts of their power from certain clean and alternative energy sources, like wind and solar. The bill faces major opposition from across the ideological spectrum.

 

Latest stories


State regulators settle over proposed transfer of Three Mile Island’s Unit 2 reactor

State environmental regulators are withdrawing their objection to a proposed license transfer for Three Mile Island’s Unit 2 reactor, after raising concerns over an accelerated decommissioning at the site.

By Rachel McDevitt

Three Mile Island operator, surrounding communities to scale back emergency planning for shuttered site

Starting in January 2021, Exelon won’t have to maintain a 10-mile planning zone around the plant and it can end off-site radiation monitoring and regular siren tests.

By Rachel McDevitt

Updated: April 17, 2020 | 12:00 pm

Pennsylvania raises alarms on transfer of radioactive Three Mile Island reactor

The Department of Environmental Protection raised several concerns related to the license transfer of TMI’s damaged Unit 2, including that “there are vast areas in the plant with unknown radiological conditions.”

By Susan Phillips

Three Mile Island wants to end siren tests, radiation monitoring as part of reduced emergency planning role

If the request is granted, the 10-mile evacuation zone surrounding TMI would cease to exist.
By David Wenner/PennLive

With TMI closed, nuclear advocates’ concern shifts to Pa.’s other plants

Those who support nuclear worry that without tax breaks, the plants will be shut out of a competitive energy market
By Katie Meyer


Three Mile Island Unit 2, site of nation’s worst nuclear accident, to be sold, dismantled

EnergySolutions would buy the site from the reactor’s owner, First Energy. The deal does not include the still-operational Unit 1 reactor.

By Marie Cusick

Three Mile Island will close Sept. 30, as nuclear rescue legislation stalls in Harrisburg

The political, historical, and energy landscape of Pennsylvania made nuclear subsidies a tougher sell here, compared to other states.

By Marie Cusick


Legacy of Three Mile Island accident, political power of gas industry makes nuclear subsidies an uphill battle in Pennsylvania

The nuclear industry says the power market isn’t built to consider a value like carbon-free emissions. But one state representative, for example, is balking at the projected cost of the subsidy.

By Marie Cusick
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