Reducing the Danger from Fires in Spent Fuel Pools Frank N. von Hippel and Michael Schoeppner (pdf file)
This page is the collection of any information about Three Mile Island (TMI) nuclear power plant.
Some of the sources here may be for or against nuclear power or TMI. PaEMT.org doesn't have a position for or against TMI or nuclear power. This page is about monitoring what's going on at the plant and being prepared for an emergency if it should occur. Hopefully, there will never be an accident or emergency at the plant. PaEMT.org is emergency services oriented. Therefore, this site is about preparing for emergencies (and other disruptive events), continuing operations through these events (continuity), managing the emergency or mitigation, and recovery or returning to normal. This page is specifically about TMI. For information about preparing or responding to a nuclear event go to the CBRN page (under Planning).
The reactor was shut down in 2019 and the plant was going to be dismantled. Now the plant is being put back into service and the reactor restarted (est. 2027) to power a Microsoft data center.
TMI is located in Londonderry Township which has a Middletown, PA 17057 mailing address.
Operating license was first isssued April 19, 1974
Unit 2 is the reactor that had a partial meltdown at 04:00 on Wednesday, March 28, 1979. That reactor is permanently shut down. (Source needed to verify the following claim: Radiation levels are still too high for an interior inspection to see what it looks like.)
Extension application submitted January 2008. License extension approved October 22, 2009. Unit 1 license extended to April 19, 2034.
Three Mile Island Unit 1 ceased operations in September 2019 for economic/profitability reasons.
Work is underway to eventually restart the reactor with an agreement from Microsoft to buy electricity to power one of its data centers. Estimated date 2027.
PaEMT doesn't have any info on which companies are building data centers near TMI or where the Microsoft data center will be located. At the time of writing this sentence... The Dauphin County Highlands Golf Course is possibly being turned into a data center. Zeager Brothers (mulching facility) in Londonderry Township is being redeveloped into a data center (Developer: Viridian Partners, Pittsburgh, PA).
U.S. Nuclear Regulatory Commission, TMI license page
If you live within about a 50 mile radius please consider getting a Safecast radiation detector and putting it online with the Safecast network. Detectors need to be in place before something happens so we know the before radiation levels. They also need to be in place before something happens to know as soon as something is happening.
Reducing the Danger from Fires in Spent Fuel Pools Frank N. von Hippel and Michael Schoeppner (pdf file)
EFMR Monitoring Group A group that monitors radiation
Three Mile Island Alert a website opposed to TMI
Pa. General Assembly, Nuclear Energy Caucus report, 2018 (pdf file)
Inside the plan to reopen TMI WSJ article, 2024 (pdf file
Rundown: All nuclear plants extended, revived, or planned as energy demand soars article October 22, 2024
"The effort to restore Unit 1 at Three Mile Island is expected to take four years, at least $1.6 billion, and thousands of workers to complete the unprecedented task of restarting a retired nuclear plant."
Three Mile Island nuclear plant gears up for Big Tech reboot By Laila Kearney October 22, 2024 1:29 PM EDT Updated October 22, 2024
Nuclear plant at TMI could reopen in 2027 Updated: 8:42 PM EDT Jun 25, 2025 WGAL local TV report
Three Mile Island nuclear plant reboot fast-tracked to 2027 By Laila Kearney June 26, 202512:48 PM EDT Updated June 26, 2025
America's largest power grid is struggling to meet demand from AI By Laila Kearney July 9, 20256:25 AM EDT Updated July 9, 2025
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U.S. Department of Energy Office of Scientific and Technical Information Investigation into the March 28, 1979 Three Mile Island accident by Office of Inspection and Enforcement (Investigative Report No. 50-320/79-10) Technical Report · 01 July 1979 OSTI ID:5621988
MANAGING NUCLEAR REACTOR ACCIDENTS: ISSUES RAISED BY THREE MILE ISLAND (pdf file 767.85 kB)
Programmatic Environmental Impact Statement: related to decontamination and disposal of radioactive wastes resulting from March 28, 1979 accident Three Mile Island Nuclear Station, Unit 2 (Docket No. 50-320). Final supplement dealing with occupational radiation dose. Supplement No. 1 Technical Report · 01 October 1984 (report pdf 5.0 MB)
Penn State University TMI-2 Clean-up Highlights Video
Three Mile Island closer to clean-up after license transfer approved