Southern Nuclear officials say a reactor at Plant Vogtle shut down during equipment maintenance.
The company said that the plant's safety systems functioned properly during the Wednesday morning incident and the reactor is stable. Plant workers are investigating the cause.
Officials say the shutdown posed no risk to the public.
Southern Nuclear is a subsidiary of Southern Co., an Atlanta-based utility that wants to build and operate two more nuclear reactors at Vogtle. If approved, they could be the nation's first new nuclear reactors in a generation.
Southern Co. has more than 4.4 million customers across the Southeast. Vogtle is near Augusta in east Georgia. A Southern Co. spokesman did not immediately return a call for comment.