Constellation says restart of Three Mile Island reactor is ahead of schedule

The company behind the planned restart of a shuttered nuclear reactor on Three Mile Island in Middletown said Wednesday that the project is currently running ahead of schedule and on track to hire hundreds of full-time employees.

A spokesperson for Constellation, which plans to spend $1.6 billion on the plant’s revival, told reporters that plans to restart Three Mile Island Unit 1 are moving quicker than anticipated. Dave Marcheskie, the community relations manager for the facility, which will be known as the Crane Clean Energy Center, said work to reopen the plant is moving “ahead of schedule,” and that more than 200 full-time workers have already been hired. 

Constellation announced in September 2024 that TMI Unit 1 would be relaunched, thanks to a 20-year power purchase agreement with Microsoft designed to power the company’s data centers. The facility is planned to be fully operational by the middle of 2028. The reactor was shut down in 2019 due to economic concerns, despite a last-minute attempt by state lawmakers to save the plant, an effort that ultimately fizzled.  

Three Mile Island Unit 1 is owned by Constellation and is a separate facility from the Three Mile Island Unit 2 reactor, which experienced a partial meltdown in 1979. That event resulted in the release of radioactive gases, which the U.S. Nuclear Regulatory Commission described as “small radioactive releases” that had “no detectable health effects on plant workers or the public.”

Marcheskie said the Crane Clean Energy Center will employ more than 600 full-time workers, and that Constellation has identified between 130 and 150 “boomerang” employees – people who previously worked at the plant and plan to return to the Middletown facility. 

Additionally, the leader of a central Pennsylvania business group hailed the planned restart of the reactor as an “economic development boon” for the region that will result in hundreds of permanent jobs and billions of dollars in investment. 

Speaking to reporters on Wednesday, Harrisburg Regional Chamber and Capital Region Economic Development Corporation President and CEO Ryan Unger said the $1.6 billion plan to restart Three Mile Island Unit 1 – a nuclear reactor that was shut down in 2019 – will bring myriad economic benefits to the Midstate region.

“When you have a company that wants to invest $2 billion in your region’s economy and employ over 600 individuals, you embrace it, and you look for a way to make sure that they’re welcome and they have the workforce they need and the project goes smoothly,” Unger said. “We welcome it as an economic development boon here for the region.”

An economic impact study commissioned by the Pennsylvania Building & Construction Trades Council, a supporter of the project, estimates that the project could create 3,400 direct and indirect jobs, including the 600 full-time positions at the plant. The report also suggests that the Crane Clean Energy Center could result in $800 million in state tax revenue, an additional $2.8 billion in federal tax revenue and $16 billion in state gross domestic product.

Marcheskie added that the purchase agreement with Microsoft is critical to powering the relaunch of the reactor. “We’ve seen an increase in demand in energy with a lot of these tech companies. Microsoft is no different than the other megatech companies,” he said. “They need additional power due to the high demand. So I think they sought us out, seeing, ‘Hey, is this even possible to restart?’ We went through all the preliminary investigations – if it was possible and feasible – and it is. They’re gonna purchase our power for 20 years, starting when we go online.”

Marcheskie looked to assuage concerns surrounding Three Mile Island that linger due to the 1979 accident, which happened at a separate reactor from Three Mile Island Unit 1.

“Since we’ve run Unit 1, we have a 45-year legacy of safety and performance. When 1 was shut down in 2019 due to economic reasons, it was one of the best-performing plans in the country – and that’s not going to change,” he said. 

The Crane Clean Energy Center currently awaits regulatory approval from the Nuclear Regulatory Commission; Constellation has also filed an interconnection request with PJM to reconnect the plant to the grid.

Unger said the project represents an economic success story for Central Pennsylvania. 

“We’ve been able to go from a plant that was being decommissioned to now being an economic boon,” he said. “That’s just, to us, a great story here that we want to tell.”