Microsoft and Constellation Energy announced a groundbreaking deal on Friday to reopen the partially melted-down Three Mile Island nuclear plant, with the tech giant committing to purchase all the power for 20 years after the restart.

The deal marks the first time a decommissioned U.S. nuclear plant has been brought back into service and the first time a commercial nuclear power plant's entire output has been allocated to a single customer.

The agreement aims to meet the growing energy demands of Microsoft's artificial intelligence (AI) operations while restarting the infamous Pennsylvania facility, the site of the worst nuclear accident in U.S. history.

Constellation Energy, the plant's owner, plans to restart Three Mile Island Unit 1 by 2028 at an estimated cost of $1.6 billion. Unit 1 sits adjacent to the reactor that suffered a partial meltdown in 1979, an event that caused national panic and severely impacted the nuclear industry.

"The nuclear power plant never should have been allowed to shut down," said Joseph Dominguez, chief executive of Constellation, in a press release. He added that the plant would produce as much clean energy as all the renewables built in Pennsylvania over the last 30 years.

The restarted facility will provide Microsoft with 835 megawatts of electricity, enough to power approximately 800,000 homes.

According to the U.S. Nuclear Regulatory Commission, on March 28, 1979, the Unit 2 reactor core at the Three Mile Island plant partially melted down when equipment malfunctions, compounded by human operator errors, caused a water pump failure, leading to a loss of coolant to the reactor.

The partial meltdown resulted in the release of radioactive gases and iodine into the environment, although no deaths or injuries were directly linked to the incident. Unit 2 remains sealed, with its highly radioactive core encased in concrete.

The revival of Three Mile Island is part of a broader trend of tech companies seeking reliable, zero-emissions power sources to support their expanding data centers and AI technologies.

However, Microsoft's plan faces significant regulatory hurdles and public skepticism. Constellation must clear extensive safety inspections from the U.S. Nuclear Regulatory Commission, which has never before authorized the reopening of a nuclear plant. The company expects the review process to be completed by 2027.

The deal has also raised questions about the use of federal subsidies, as the project relies heavily on tax breaks for nuclear power included in the 2022 Inflation Reduction Act. Critics argue that using public funds to benefit a single private company may be inappropriate.

Social media reactions to the news have been mixed.

One commenter on The Washington Post's website sarcastically suggested, "OK, as long as the waste is sent to Microsoft HQ in Redmond, WA."

Another user on The Verge expressed concerns about broader implications: "The potential power demand is looking to be so large, it will delay the transition to carbon-free energy (here in the U.S.) and not by a little bit ... Seems like a law saying all electricity for AI and crypto farms in the U.S. has to be carbon-free is in order."

Some community leaders welcomed the potential economic revival, with a study funded by the Pennsylvania Building and Construction Trades Council projecting the creation of 3,400 jobs and $3 billion in state and federal taxes.

Pennsylvania Governor Josh Shapiro expressed support, saying that the plant will "safely utilize existing infrastructure to sustain and expand nuclear power in the Commonwealth while creating thousands of energy jobs," according to a Constellation press release.

However, nuclear safety advocates have voiced concerns.

Henry Sokolski, a former deputy for nonproliferation policy at the Pentagon, criticized the use of public subsidies, telling The Washington Post, "Microsoft says it will buy all of the nuclear electricity from Three Mile Island, but it wants rate and taxpayers to pick up the tab to refurbish the plant."