NEW YORK (Reuters) - Constellation Energy is making its case to restore the operating license for its Three Mile Island nuclear power plant in the first public meeting before the U.S. Nuclear Regulatory Commission on Friday on the unprecedented project to restart a retired reactor.

Constellation, which announced last month that it had signed a 20-year power purchase agreement with Microsoft (MSFT) that would enable the reopening Unit 1 reactor at Three Mile Island, is also seeking to extend the life of the plant and change its name to the Crane Clean Energy Center.

Three Mile Island, located in Pennsylvania, is widely known for the 1979 partial meltdown of its Unit 2 reactor that was permanently shut following the largest nuclear accident in U.S. history.

The site's Unit 1 was shut due to economic reasons in 2019, some 15 years before the license was set to expire. Constellation completed initial testing this year 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 Worth said at the NRC meeting.

No nuclear power plant has been restarted after being retired.

The 835-megawatt reactor, which is expected to restart in 2028, would deliver power to the grid to offset electricity use by Microsoft's data center in the region.

The effort to restore Three Mile Island, which is expected to start work in the first quarter of 2025, cost at least $1.6 billion, and require thousands of workers, still requires licensing modifications and permitting. Local activists have also vowed to fight the project over safety and environmental concerns.

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.

(Reporting by Laila Kearney; Editing by Marguerita Choy)