Constellation, which announced last month that it had signed a 20-year power purchase agreement with Microsoft that would enable reopening the Unit 1 reactor at Three Mile Island, made its case before the Nuclear Regulatory Commission to restore its operating license for the plant.
The company also sought to extend the life of the plant and change its name to the Crane Clean Energy Center.
Three Mile Island, which is located in Pennsylvania on an island in the Susquehanna River, is widely known for the 1979 partial meltdown of its Unit 2 reactor. That unit has been permanently shut and is being decommissioned.
Members of the NRC requested details about the emergency evacuation plans for the restarted plant and information about the commercial deal with Microsoft, while imploring Constellation to quickly work on permitting related to its water use for the plant.
The NRC also raised questions about how the restart of Unit 1 would intersect with the decommissioning of Unit 2, which began last year, nearly 45 years after the partial meltdown.
Utah-based nuclear services company EnergySolutions owns Unit 2 and related infrastructure, while Constellation owns Unit 1 and the site's land.
Unit 1 shut down due to economic reasons in 2019, some 15 years before the operating license was set to expire. At the time, Constellation said it did not anticipate a restart.
Earlier this year, Constellation completed initial testing on the reactor and determined it was physically, and financially, possible to resurrect it.
"We understand how we shut it down and we have a good idea of how we are going to restart this," plant manager Trevor Orth said at the NRC meeting.
The physical work to restore Three Mile Island, which is expected to start in the first quarter of 2025, cost at least $1.6 billion, and could require thousands of workers, still needs licensing modifications and permitting.
Local activists have also vowed to fight the project over safety and environmental concerns, including the storage of nuclear waste on the site.
Scott Portzline, who is with nuclear watchdog group Three Mile Island Alert in Harrisburg, questioned the site's backup power and criticized the proposed nuclear control room simulator used for training.
"I have a constitutional right to know how my nuclear plants are operating and the utility ought to be able to answer that," Portzline said during the meeting.
Local businesses and the building trades made comments in support of plant's comeback in the meeting.
Under the National Environmental Policy Act, the NRC will be required to complete an environmental assessment within the final year of any restart. The plant will require other environmental permits, including ones for air emissions and water pollutants.