Nuclear power is getting a second act, and Three Mile Island is center stage. The Trump administration has greenlit a $1 billion credit facility for Constellation Energy Corp. (CEG) to reopen the infamous Pennsylvania site, according to the Wall Street Journal. The facility, now rebranded as the Crane Clean Energy Center, will funnel its electricity exclusively to Microsoft Corp. (MSFT) under a 20-year power purchase agreement.

Powering the AI Boom

Why does Microsoft need an entire nuclear reactor? Artificial intelligence. Running AI operations requires massive amounts of reliable, round-the-clock electricity, and tech giants are scrambling to secure dedicated power sources. Microsoft apparently decided that locking down 800 megawatts of carbon-free nuclear capacity was worth the commitment.

More Than Just Tech Infrastructure

For the White House, this isn't just about keeping the lights on for AI models. Energy Secretary Chris Wright framed the project as an inflation-fighting tool, arguing that expanding electricity supply will help control consumer prices. "We want to bring as much addition of reliable electricity onto the grid to stop these price rises," Wright said, adding that the effort supports plans to "reshore manufacturing in our country."

Constellation executives echoed the enthusiasm, crediting the administration's regulatory approach with making it possible to "vastly expedite this restart without compromising quality or safety. It's a great example of how America first energy policies create jobs, growth and opportunities and make the grid more reliable."

A Reactor with Baggage, But Not That Baggage

Let's address the elephant in the room: yes, this is Three Mile Island, site of the worst nuclear accident in U.S. history. But the reactor being restarted wasn't involved in that 1979 partial meltdown. It operated safely for decades until it was shut down in 2019, not because of safety issues, but because it couldn't compete economically with dirt-cheap natural gas.

Constellation plans to invest approximately $1.6 billion to bring the reactor back online by 2027. Once operational, it will deliver roughly 800 megawatts of carbon-free capacity to the grid.

Trump's Nuclear Ambitions

This restart fits into President Donald Trump's ambitious goal to quadruple American nuclear output by mid-century. The strategy involves reviving shuttered plants and constructing ten new large-scale reactors, expanding total capacity from 100 gigawatts to 400 gigawatts.

That's a dramatic shift. The U.S. grid has added only three major reactors since the 1990s, a period when nuclear construction essentially ground to a halt. Wright suggested the Nuclear Regulatory Commission is now working to cut through bureaucratic red tape, noting that "with the new generation of reactors that's even easier."

Constellation Energy shares jumped 2.33% to $347.25 in extended trading Tuesday following the announcement.