Three Mile Island considers nuclear restart as Pa. lawmakers look to new tech to meet demand

This story originally appeared on StateImpact Pa

The company that owns one reactor at Three Mile Island near Harrisburg is floating the idea of reopening the shuttered nuclear plant.

TMI’s Unit 1 reactor closed in 2019 because owner Exelon said it wasn’t competitive against cheaper methane gas and renewable sources amid flat demand for power.

But demand is growing now with the rise of data centers and new technology, making the plant’s owner question if it could be worth it to reopen. TMI-1 is now owned by Constellation, a company formed in 2022 when Exelon split its power generation and transmission businesses into two companies.

Constellation spokesman Dave Snyder said the effort to reopen a closed plant in Michigan sparked the discussion about TMI.

He said the company is always looking for ways to add more clean energy and that extending licenses at current plants is the most immediate way to do that. Restarting closed plants is another opportunity.

“Though we have determined it would be technically feasible to restart the unit, we have not made any decision on a restart as there are many economic, commercial, operational and regulatory considerations remaining,” Snyder said.

TMI’s Unit 2 reactor partially melted down in 1979 and never came back online. The accident was the worst at a commercial nuclear site in the country, causing the evacuation of an estimated 80,000 people from central Pennsylvania. The Nuclear Regulatory Commission said radioactive releases during the accident were low enough that they would not be expected to negatively impact health, though some people in the area have contested that. The incident effectively stopped nuclear power’s growth in the U.S. for decades.

In 2020 Energy Solutions took over the license for TMI-2 and began decommissioning. It plans to finish the cleanup by 2037.

Unit 1 was not affected by the accident, and had been licensed to operate until 2034.

Gov. Josh Shapiro’s office did not say whether the state is involved in Constellation’s plans.

Shapiro’s spokesperson Manuel Bonder emphasized Shapiro’s “all-of-the-above” energy strategy and said the administration “recognizes the role Pennsylvania’s nuclear generation fleet plays in providing safe, reliable, carbon-free electricity that helps reduce emissions and makes Pennsylvania’s energy economy more competitive.

“The Governor supports efforts to ensure the reliability of Pennsylvania’s energy grid while protecting and creating energy jobs,” Bonder said.

There is no playbook for restarting a retired nuclear plant, said Patrick White, research director of the nonpartisan think tank Nuclear Innovation Alliance, which promotes advanced nuclear energy.

After stopping power generation, some nuclear plants including TMI-1 enter a period of dormancy known as SAFSTOR. White said this involves removing spent fuel from the reactor, then waiting decades for radioactivity to decay naturally before dismantling the plant.

White said companies are now looking at what’s needed to bring shuttered systems back online. That would be identified on a plant-by-plant basis. He said many of the plants that closed in the last decade did so mainly for financial reasons, not safety reasons.

The fact that companies are reexamining these plants shows “a growing recognition of the importance of all clean energy sources, including nuclear, when we think about what is it going to take to hit our climate goals,” White said.

Talks of TMI restarting come as state lawmakers revamp the bipartisan, bicameral Nuclear Energy Caucus.

Rep. Rob Matzie (D-Beaver) co-chairs the caucus, which originally formed in an effort to keep TMI open past 2019.

“From the exploration perspective, it’s probably worthy. I’m sure there will be some public outcry from that perspective just because of it being Three Mile Island,” Matzie said of the possibility of restarting Unit 1.

Matzie and others are relaunching the caucus now because he said a lot has changed since 2019; new technology is making big demands on the electric grid, and the federal government is incentivizing zero-emission electricity.

He said the goal is first to educate fellow lawmakers about the energy source and how it affects the state’s economy.

“This is baseload generation. So, if we want manufacturing to happen in Pennsylvania, advanced manufacturing to happen in Pennsylvania, and also to be carbon-free, this is the only way to go,” Matzie said.

Matzie said new nuclear technologies on the horizon, such as small modular reactors, mean state lawmakers need to be prepared to write laws guiding the adoption of new tech and creating safeguards for the public.

Matzie also wants the caucus to look into the reuse of retired coal and gas plants to host small reactors.

“The high power lines, transmission is there. So, that’s one less thing you have to do. And that’s a major component of getting generation out to the grid,” he said.