United States · 40.154, -76.725Three Mile Island
Three Mile Island, nuclear power plant in United States, is preparing the restart of one pressurized water reactor of 835 MW net, not generating since 2019, with a return to service expected in 2027.
Three Mile Island 1's restart is announced for 2027.
- Country
- United States
- Units
- 3
- Technology
- PWR
- Net capacity
- —
- First grid connection
- 1974
- Operator
- Exelon Generation · General Public Utilities
- Owner
- Exelon Corp · Constellation Energy Corp
- Status
- Restarting
See also: alerts for this plant · every plant in United States · Nuclear power plants in Pennsylvania · Vendor: Babcock & Wilcox · every PWR reactor · how a PWR works
- NRC authorizes receipt of new fuel at the Crane Clean Energy Center
License Amendment 307 for the former Three Mile Island 1: the plant may receive and store fresh fuel and neutron sources while the restart review continues.
- Draft environmental assessment: the restart would have no significant impact
The NRC issued the draft environmental assessment and draft finding of no significant impact, with public comments until July 8. The final version is projected for September 2026.
- Department of Energy closes a $1 billion loan for the restart
The Loan Programs Office finances part of the restoration of the 835 MW unit, which would power the equivalent of about 800,000 homes on the PJM grid.
- Three Mile Island 1 officially renamed Christopher M. Crane Clean Energy Center
License Amendment 306: the NRC accepts the facility's new name, in honour of former Exelon CEO Chris Crane.
- Constellation ahead of schedule for the restart
Over 200 employees hired and a new main power transformer ordered for 2026; return to service brought forward to 2027, a year ahead of the original plan.
- Constellation announces the restart of Three Mile Island 1 with a 20-year deal with Microsoft
Five years after the economic shutdown, a power purchase agreement with Microsoft for its data centres funds the return of 835 MW of carbon-free power to the grid.
Units
| Unit | Type | Model | Status | MWe | MWt | Construction start | Grid connection | Closure | Load factor |
|---|---|---|---|---|---|---|---|---|---|
| Three Mile Island 1 | Pressurized water (PWR) | Babcock & Wilcox lowered-loop (B&W LLP) | Restarting · restart expected 2027 | 835 | 2,568 | May 18, 1968 | Jun 1974 | Sep 2019 | — |
| Three Mile Island 2 | Pressurized water (PWR) | B & W (DRY) | Shut down | 880 | 2,772 | Nov 1969 | Apr 1978 | Mar 1979 | — |
| Three Mile Island Unit 1 Repower | Pressurized water (PWR) | Babcock & Wilcox lowered-loop (B&W LLP) | Planned | 819 | — | — | 2027 (planned) | — | — |
Data: IAEA PRIS · Global Energy Monitor · editorial review · updated on Sep 21, 2026
Three Mile Island 1, an 835 MWe PWR (Babcock & Wilcox lowered-loop (B&W LLP)), started construction in 1968 and operated from 1974 to 2019; its restart is expected in 2027 as the Crane Clean Energy Center.
Three Mile Island 2, an 880 MWe PWR (B & W (DRY)), started construction in 1969 and operated from 1978 to 1979.
Three Mile Island Unit 1 Repower, an 819 MWe PWR (Babcock & Wilcox lowered-loop (B&W LLP)), is planned, with grid connection expected in 2027.
Operator: Exelon Generation (Three Mile Island 1) · General Public Utilities (Three Mile Island 2).
Owner: Exelon Corp (Three Mile Island 1) · Constellation Energy Corp (Three Mile Island Unit 1 Repower).