Constellation Energy receives NRC environmental finding for 835 MW restart
The Sept. 25 finding addresses environmental effects; operating-licence changes and inspections remain before the Pennsylvania unit can resume power.
Ines Halvorsen
On Sept. 25, the U.S. Nuclear Regulatory Commission issued a final environmental finding for the proposed restart of an 835-megawatt Pennsylvania reactor operated by Constellation Energy Generation, LLC, a unit of Constellation Energy Corporation NASDAQCEG. A US$1 billion interest-bearing federal loan closed in November 2025 to help finance the work, which Constellation said would lower its financing costs. Constellation's September 2024 announcement names Microsoft NASDAQMSFT as the counterparty to a 20-year power purchase agreement.
The NRC's notice calls the determination a finding of no significant impact for proposed federal actions at the Christopher M. Crane Clean Energy Center, formerly Three Mile Island Unit 1. The notice carries docket 50-289 and follows a draft environmental assessment published June 8 for public comment. It is an environmental determination, while the agency's separate review of requests to restore power operations continues.
Constellation shares closed at US$260.43 on Sept. 28, according to the NASDAQCEG quote page, which carried a 4 p.m. EDT time stamp. The close followed the Sept. 25 notice; the quote alone does not establish how much of the price reflected the agency's finding.
The unit stopped operating on Sept. 26, 2019, according to the NRC. Constellation's September 2024 release listed the turbine, generator, main power transformer, and cooling and control systems among the equipment it intended to restore. The release did not give delivery dates for those components, so the finding does not itself set a date for power deliveries.
NRC Still Reviewing Operating-Licence Changes
The NRC's reactor status page lists Constellation's July 31, 2025 request to revise the operating licence and technical specifications for resumed power operations as under review. Separate requests concern the plant's physical security and emergency plans. The agency also says it will inspect restored components before deciding whether the unit is ready to operate.
"To restart CCEC, Constellation would need to (1) gain NRC approval to restore the licensing basis of the plant to an operational status; (2) return plant components to a status that supports safe operation; and (3) make any upgrades necessary to meet the proposed operational licensing basis."
The NRC sets out those requirements on its reactor status page. Its environmental finding resolves one part of that review, while the licence changes and inspections remain on the agency's work list.
The September 2024 power agreement gives Constellation a buyer for the restarted unit's output over 20 years. Constellation did not disclose a price per megawatt-hour in that announcement, so the contract's revenue cannot be calculated from the stated 835-megawatt capacity alone. The November 2025 loan is financing for the restart, rather than an additional power sale.
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The next NRC step is a decision on Constellation Energy Generation, LLC's July 31, 2025 operating-licence request. The agency lists no decision date and says it will inspect restored components before deciding whether the reactor is ready to operate.
