HARRISBURG — A long-dormant nuclear reactor on Three Mile Island is one step closer to returning to service after the U.S. Department of Energy approved a $1 billion loan to Constellation Energy. The funding aims to restart the 835-megawatt unit at the Crane Clean Energy Center, located on the Susquehanna River in Londonderry Township, Dauphin County — just south of Harrisburg.

The reactor, best known as part of the site of the 1979 accident, has been shut down since 2019 but was never fully dismantled. The accident involved a partial meltdown at Unit 2 caused by equipment failures and operator error, resulting in a small release of radioactive material. No injuries or harmful health effects were ever linked to the event, and studies found that nearby residents received only minimal radiation exposure. The incident prompted major improvements in safety standards, operator training, and emergency-response planning across the U.S. nuclear industry, while Three Mile Island’s Unit 1 continued to operate safely until 2019.

Path to Restart

If the Nuclear Regulatory Commission grants final approval, the restart would bring back a major source of carbon-free baseload power for Pennsylvania and the Mid-Atlantic grid. Federal officials say the revived unit could generate enough electricity to power about 800,000 homes.

Constellation Energy announced last year that it would invest $1.6 billion to restart the unit under a 20-year agreement to supply power to Microsoft’s data centers. The company has since renamed the facility the Crane Clean Energy Center and is working to restore major components, including the turbine, generator, main power transformer, and both cooling and control systems, with a goal of bringing the plant back online in 2027.

Economic Impact and Policy

Pennsylvania stands to see significant economic benefits as well. The project is expected to create more than 600 jobs during the restart process, with additional long-term positions tied to ongoing operations and maintenance.

The loan is part of the Trump administration’s broader strategy to revitalize the nation’s nuclear sector. A May executive order laid out plans to rebuild the domestic nuclear supply chain, restart closed reactors, expand uranium production, and grow the U.S. nuclear workforce — efforts that could directly affect Pennsylvania, one of the nation’s leading nuclear-power states.

Local officials say the project could help stabilize the regional grid and strengthen the state’s role in national energy policy, though the plant still faces a detailed federal review before it can return to generating power.

If approved, Three Mile Island’s comeback would mark a significant moment for both Pennsylvania’s energy economy and the broader U.S. push for nuclear resurgence.