Three Mile Island Nuclear Generating Station
| Three Mile Island Nuclear Generating Station | |
|---|---|
Three Mile Island in 2019, prior to shutdown. | |
| Official name | Unit 1: Crane Clean Energy Center |
| Country | United States |
| Location | Londonderry Township, Dauphin County, Pennsylvania |
| Coordinates | 40°9′14″N 76°43′29″W / 40.15389°N 76.72472°W |
| Status | Mothballed |
| Construction began | Unit 1: May 18, 1968 Unit 2: November 1, 1969 |
| Commission date | Unit 1: September 2, 1974 Unit 2: December 30, 1978 |
| Construction cost | $1.557 billion (2007 USD) ($2.00 billion in 2023 dollars) |
| Owners | Unit 1: Constellation Energy Unit 2: EnergySolutions |
| Operator | Constellation Energy |
| Employees | 725 (2017) |
| Nuclear power station | |
| Reactor type | PWR |
| Reactor supplier | Babcock & Wilcox |
| Cooling towers | 4 × Natural Draft, each 113.4 metres (372 ft) tall |
| Cooling source | Susquehanna River |
| Thermal capacity | 1 × 2568 MWth |
| Power generation | |
| Make and model | B&W LLP (DRYAMB) |
| Units decommissioned | 1 × 880 MW, 1 × 819 MW ( restart planned ) |
| Nameplate capacity | 819 MW |
| Capacity factor | 95.65% (2017) 73.25% (lifetime) |
| Annual net output | 7.3 TWh (2018) 245.12 TWh (lifetime) |
| External links | |
| Website | www |
| Commons | Related media on Commons |
Three Mile Island Nuclear Generating Station (abbreviated as TMI), is a shut-down nuclear power plant on Three Mile Island in Pennsylvania, US, on the Susquehanna River just south of Harrisburg. It has two separate units, Unit 1 (TMI-1) (owned by Constellation Energy) and Unit 2 (TMI-2) (owned by EnergySolutions).
The plant was the site of the most significant accident in United States commercial nuclear energy when, on March 28, 1979, TMI-2 suffered a partial meltdown. According to the U.S. Nuclear Regulatory Commission (NRC) report, the accident resulted in no deaths or injuries to plant workers or in nearby communities. Follow-up epidemiology studies did not find causality between the accident and any increase in cancers. One work-related death has occurred on-site during decommissioning.
The reactor core of TMI-2 has since been removed from the site, but as of 2009 the site has not been fully decommissioned. In July 1998, Amergen Energy (now Exelon Generation) agreed to purchase TMI-1 from General Public Utilities for $100 million.
The plant was originally built by General Public Utilities Corporation, later renamed GPU Incorporated. The plant was operated by Metropolitan Edison Company (Met-Ed), a subsidiary of the GPU Energy division. In 2001, GPU Inc. merged with FirstEnergy Corporation. On December 18, 2020, FirstEnergy transferred Unit 2's license to EnergySolutions' subsidiary, TMI-2 Solutions, after receiving approval from the NRC.
Exelon was operating Unit 1 at a financial loss since 2015. In 2017, the company said it would consider ceasing operations at Unit 1 because of high costs unless there was action from the Pennsylvania government. Unit 1 officially shut down at noon on September 20, 2019.
Unit 1 decommissioning was expected to be completed in 2079 and would have cost $1.2 billion, but in September 2024, Constellation Energy, the owner of the Unit, announced plans to invest $1.6 billion to bring the facility back online. The plant is expected to resume operations in 2028 as the Crane Clean Energy Center (CCEC). The entirety of the plant's energy output will be sold to Microsoft Corporation. Microsoft entered into a 20-year agreement to purchase as much electricity as possible from the plant, which will support the company’s growing energy needs for its expanding network of data centers.
Unit 2, which has been dormant since the accident in 1979, is expected to close in 2052.