In April 2011, Exelon of Chicago announced its intention to purchase Constellation Energy, the owner and operator of Nine Mile Point Nuclear Station.

The acquisition was approved by FERC and the companies officially combined on March 12, 2012, with Constellation Energy taking the Exelon name.

Construction of both units, along with neighboring Fitzpatrick, was commissioned by Niagara Mohawk Power Corporation.

[citation needed] In early May 2011, the plant operator reported that the plant fuel supplier, General Electric, notified the operator that mathematical errors could've resulted in the reactor's fuel getting hotter than expected.

[4] In 2016, Governor of New York Andrew Cuomo directed the Public Service Commission to consider ratepayer-financed subsidies similar to those for renewable sources to keep nuclear power stations profitable in the competition against natural gas.

[5][6] Unistar Nuclear, a joint venture between Constellation Energy and Électricité de France (EDF), announced in late 2008 that it had notified the U.S. Nuclear Regulatory Commission (NRC) of its plan to submit a combined construction and operating license (COL) application for a European Pressurized Reactor (EPR) at Constellation Energy's Nine Mile Point site.

[8] The Nuclear Regulatory Commission defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone with a radius of 10 miles (16 km), concerned primarily with exposure to, and inhalation of, airborne radioactive contamination, and an ingestion pathway zone of about 50 miles (80 km), concerned primarily with ingestion of food and liquid contaminated by radioactivity.