July 10, 2023 – Unit 3 at the Vogtle nuclear power plant was forced to shut down at about 1:30 p.m. on July 9 due to a reduction in reactor coolant flow, while the unit was operating at 45 percent power, according to the U.S. Southern Nuclear Operating Co.
The U.S. Nuclear Regulatory Commission (NRC) said the unit operated at 15 percent power on July 7 and 8, then reached 60 percent power on July 9, indicating that the unit was connected to the grid at this time.
In its incident report, Southern Nuclear Operating Company noted that Vogtle Unit 3 was conducting a power ramp-up test when the reactor coolant pump voltage dropped, causing a reduction in coolant flow and triggering the reactor’s automatic protection system.
The unit had previously been out of service since June 11, 2023, due to problems with the main generator.On June 16, Southern Company, the parent company of Southern Nuclear Operating Company, told the NRC that inspections had found degradation of the unit’s generator hydrogen seals and that it would restart the unit after completing the related repair work. Commercial operation of the unit was delayed from June 2023 to July.