Nuclear energy operator Constellation Energy will reopen the Three Mile Island facility in Pennsylvania, the site of a 1979 partial nuclear meltdown, as part of a deal with Microsoft to power data centers. In the announcement Friday, Constellation said Microsoft has agreed to buy 20 years’ worth of power from the operator beginning in 2028. The U.S. Nuclear Regulatory Commission must review and approve the decision before the plant reactor can be restarted. The agreement involves the plant’s second reactor, which was unaffected by the 1979 accident and continued to operate for decades after. The 1979 partial meltdown was the worst in the history of U.S. commercial nuclear generation and, although it did not cause any deaths, exacerbated public concerns around the safety of nuclear power, along with the much costlier and deadlier Chernobyl disaster in the Soviet Union seven years later. The plant was retired due to declining revenues in 2019. “Powering industries critical to our nation’s global economic and technological competitiveness, including data centers, requires an abundance of energy that is carbon-free and reliable every hour of every day, and nuclear plants are the only energy sources that can consistently deliver on that promise,” Constellation CEO Joe Dominguez said in a statement. “Before it was prematurely shuttered due to poor economics, this plant was among the safest and most reliable nuclear plants on the grid, and we look forward to bringing it back with a new name and a renewed mission to serve as an economic engine for Pennsylvania,” he added. The announcement comes as part of a broader renaissance in commercial nuclear power as lingering Cold War-era anxieties have given way to demand for reliable carbon-free sources of power. That demand is particularly acute in the case of artificial intelligence data centers, which currently comprise up to 1.5 percent of electricity use worldwide, according to an analysis by the International Energy Agency.