The Three Mile Island nuclear plant in Londonderry Township, Pa.
Credit...Andrew Caballero-Reynolds/Agence France-Presse — Getty Images

Three Mile Island Plans to Reopen as Demand for Nuclear Power Grows

The infamous plant, closed since 2019, is getting a new lease on life after Microsoft agreed to buy its electricity to supply a growing fleet of data centers.

by · NY Times

In a striking sign of renewed interest in nuclear power, Constellation Energy said on Friday that it plans to reopen the shuttered Three Mile Island nuclear plant in Pennsylvania, the site of the worst reactor accident in United States history.

Three Mile Island became shorthand for the risks posed by nuclear energy after one of the plant’s two reactors partly melted down in 1979. The other reactor kept operating safely for decades until finally closing, for economic reasons, five years ago.

Now a revival is at hand. Microsoft, which needs tremendous amounts of electricity for its growing fleet of data centers, has agreed to buy as much power as it can from the plant for 20 years. Constellation plans to spend $1.6 billion to refurbish the reactor that recently closed and restart it by 2028, pending regulatory approval.

“The symbolism is enormous,” said Joseph Dominguez, chief executive of Constellation, the nation’s largest nuclear operator. “This was the site of the industry’s greatest failure, and now it can be a place of rebirth.”

Until recently, the U.S. nuclear industry seemed to be in permanent decline. Electric utilities closed 13 reactors between 2012 and 2022 in the face of competition from cheap natural gas and growing wind and solar power.

But with energy demand spiking and fears of climate change rising, many states and businesses are reconsidering nuclear power, which can produce electricity around the clock without emitting the greenhouse gases that are heating the planet.

Congress recently approved a tax credit aimed at keeping existing nuclear reactors running for years to come. In California, lawmakers reversed a decision to shut down the Diablo Canyon nuclear plant. And in Michigan, Holtec International is looking to restart the Palisades nuclear plant, which closed in 2022.

It’s no easy feat to reopen a nuclear reactor that has been mothballed for years.

Constellation workers have been inspecting the closed reactor at Three Mile Island for the last 20 months, checking for signs of corrosion or decay. The company would need to replace the reactor’s main power transformer as well as restore its turbines and cooling systems.

It also needs about 600 workers to staff the plant. When Three Mile Island shut down in 2019, most of its employees were sent by Constellation to other states. Many are now eager to return, Mr. Dominguez said.

If restored, the reactor would have a capacity of 835 megawatts, enough to power more than 700,000 homes. It will remain unaffected by the other reactor that melted down in the 1970s, known as Unit 2, which is currently in the process of being dismantled.

The new plant will also get an image makeover. It will be renamed the Crane Clean Energy Center, after a former chief executive Chris Crane, who died in April.

Politicians in Pennsylvania hailed the announcement.

“This will transform the local economy and presents a rare opportunity to power our economy with reliable clean energy that we can count on,” said Tom Mehaffie, a Republican state representative whose district includes the plant. “This is a rare and valuable opportunity to invest in clean, carbon-free and affordable power — on the heels of the hottest year in Earth’s history.”

One recent poll found that 57 percent of Pennsylvania residents supported reopening Three Mile Island “as long as it does not include new taxes or increased electricity rates.”

Mr. Dominguez said that Constellation would pay to refurbish the plant entirely out of its own pocket, and Microsoft would be on the hook for buying electricity from the plant for 20 years. “We’re not asking for a penny from the state or from utility customers,” he said.

Some people remain opposed to any restart. In August, about a dozen protesters stood outside the plant’s gates to protest the potential reopening, holding up signs commemorating the accident and recalling how residents were forced to evacuate after the partial meltdown, which caused no casualties but triggered widespread panic.

Edwin Lyman, a physicist and critic of nuclear power at the Union of Concerned Scientists, said that safely reviving a reactor that had been shut down for so long could prove more technically challenging than expected. “No one’s really done this before,” he said.

Tech companies like Microsoft and Amazon have shown an increasing interest in nuclear power as they struggle to meet the growing energy demands of artificial intelligence. Data centers need power 24 hours a day, something wind and solar power alone can’t provide. But many tech firms also have ambitious targets for fighting climate change and prefer not to use electricity produced by burning coal or gas.

“Only a few short years ago, tech companies scoffed at buying nuclear electricity,” said Mark Nelson, managing director of Radiant Energy Group, an energy consultancy. “The return of Three Mile Island is the return of hard reality.”

Just a handful of recently retired reactors in the United States could plausibly be brought back online, however. That includes Three Mile Island, the Palisades plant in Michigan and the Duane Arnold plant in Iowa. The rest are too far along the process of decommissioning, experts said.

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