“The unit is safe and stable, and plant personnel are investigating the cause of the shut down,” the company said in a statement. “There was no risk to the public.”
The unexpected shutdown occurred at 9:06 a.m., a company statement said, and involved only Unit 1.
Amoi Geter, a Southern Nuclear spokeswoman, said workers noticed water levels rising inside the unit’s steam generator during maintenance work involving a valve that controls the unit’s water flow. The unit subsequently shut itself down, as it was designed to do.
Unit 2 remained in operation Wednesday afternoon, at 97 percent of power, as workers prepare that reactor for a scheduled refueling outage.
Plant Vogtle is located near Waynesboro, Ga. Unit 1 began commercial operation in May 1987 and generates 1,215 megawatts of electricity.
Wednesday’s shutdown is the second such incident this year.
On April 21, a breaker in Unit 1 tripped for an unknown reason, triggering an automatic shutdown. The breaker and related equipment were removed and replaced after the outage, and the reactor was restarted without incident.
Vogtle has two existing units and is also in line to be the first site in the U.S. where new commercial power reactors will be built in almost 30 years.
Site work for units 3 and 4 has been under way since last year, and the company is awaiting final permits from the Nuclear Regulatory Commission before moving ahead with construction.