The Nuclear Regulatory Commission (NRC) announced it would launch a special inspection at Unit 1 of the Joseph M. Farley nuclear plant due to a “partial loss of off-site power and subsequent issues with a turbine-driven auxiliary feed pump.”

The two-unit Farley plant, located in southern Alabama, is owned by Alabama Power and operated by Southern Company. Unit 2 was not affected and there was no threat to public safety.

According to NRC, Unit 1 automatically shut down due to the partial loss of offsite power on August 3. One of the emergency power buses, which provides electricity to safety equipment, also lost power.

The plant’s emergency diesel generator automatically started, restoring power to the emergency bus, and the auxiliary feed system provided reactor cooling, as designed, placing the plant in a safe condition.

NRC said a short time later, while operators were shutting down the auxiliary feed pump, which was no longer needed, the pump automatically restarted and then tripped. Operators then declared the pump not operable.

“While this event didn’t present a threat to public health and safety, because redundant systems ensured the plant was safely shutdown, we want to independently gather additional information on what happened and why it happened,” said NRC’s Laura Dudes.

A spokesperson for Southern Nuclear said operators corrected the issue, and the plant was safely returned to power August 6.

“Southern Nuclear fully supports the NRC inspection as part of NRC’s mission of ensuring plants are running safely and in accordance with design and procedure,” the spokesperson said.

Construction of the Farley plant began in 1970. Unit 1 achieved commercial operation in December 1977 and Unit 2 entered operation in July 1981. The total cost of the plant was about $1.57 billion.

The two units have a total capacity of 1,800 MW and the plant is powered by Westinghouse Pressurized Water Reactors.

The NRC’s inspection report will be issued about 45 days after the inspection is completed.