The U.S. Department of Energy has formalized $6.51 billion in federal loan guarantees for the expansion of a Georgia nuclear power plant.

The federal loan guarantees are to support construction of two new nuclear reactors at the Alvin W. Vogtle Electric Generating Plant, near Waynesboro in eastern Georgia, representing the first new nuclear power project in the nation in nearly three decades.

U.S. Secretary of Energy Ernest Moniz announced the loan guarantees Wednesday prior to his visit to the Vogtle facility Thursday for a ceremony.

"The construction of new nuclear power facilities like this one -- which will provide carbon-free electricity to well over a million American energy consumers -- is not only a major milestone in the administration's commitment to jumpstart the U.S. nuclear power industry, it is also an important part of our all-of-the-above approach to American energy as we move toward a low-carbon energy future," Moniz said in a release.

Of the $6.51 billion in loan guarantees, $3.46 billion will go to Georgia Power, a subsidiary of Southern Company, and $3.05 billion will go to Oglethorpe Power Co., a partner in the Vogtle expansion.

A federal loan worth $1.8 billion is pending for the Municipal Electric Authority of Georgia.

Vogtle's two existing nuclear reactors, with a total capacity of 2,430 megawatts, have been in operation since the late 1980s.

The two new 1,100 megawatt Westinghouse AP1000 nuclear reactors for units 3 and 4 are expected to begin commercial operation in 2017 and 2018, respectively, Southern says, making Vogtle the only four-unit nuclear facility in the nation.

Southern says the project will employ approximately 5,000 people during peak construction and create 800 permanent jobs once the plant begins operating.

Southern Company chief executive Thomas Fanning in a statement said the Vogtle project "is a carbon-free source of baseload generation necessary to create American energy security."

"Our partnership with the Department of Energy is an important step in moving the U.S. nuclear industry forward," Fanning said.

But environmental group Friends of the Earth criticized federal support for nuclear power, citing the Fukushima nuclear power plant disaster resulting from Japan's March 2011 earthquake and tsunami, which it says "demonstrated that nuclear reactors can never be safe."

"Despite the dangers nuclear reactors pose and the lack of any sustainable solutions for nuclear waste disposal, President Obama's commitment to nuclear energy succeeds only in condemning future generations to live with the fallout," said Katherine Fuchs, the group's nuclear campaigner, in a statement after the DOE's announcement of the loan guarantees.