Georgia Power, a subsidiary of Atlanta-based Southern Co, says vibrations found in a cooling system of unit 4 at the Vogtle NPP means that the plant will not start commercial operation until the second quarter of 2024, or between 1 April and 30 June 30. Previously operation was set for 30 March. In a filing to investors Georgia Power said the vibrations "were similar in nature" to those experienced during start-up testing for unit 3, which began commercial operations last year.
At unit 3, the utility found that a pipe vibrated during testing because construction workers failed to install enough bracing. Georgia Power said the unit 4 problem has already been fixed but significant testing still needs to be done. Georgia Power estimated a loss of $30m in profit for every additional month of delay because of an earlier order by state utility regulators.
The five members of the Georgia Public Service Commission ruled that the company cannot earn any additional return on equity through a construction surcharge levied on Georgia Power's 2.7m customers after 30 March. The construction budget will not be affected provided unit 4 begins operating by June 30. However, Georgia Power said it would have to pay $15m a month in extra construction costs if the project extends into July.
Vogtle 4 suffered previous delays in October 2023 following the discovery of a malfunctioning coolant pump. The unit had been expected begin operation later in 2023 but this was revised to the first quarter of 2024. The problem with the coolant pump was an “isolated event,” Georgia Power said in a report filed with the US Securities & Exchange Commission.
Fuel loading at Vogtle 4 began in August 2023. Unit 3 began commercial operation at the end of July 2023. Vogtle 3&4 are both 1,117 MWe Westinghouse AP1000 pressurised water reactors (PWRs). The two units were originally expected to cost about $14bn and to enter service in 2016 and 2017 but suffered a series of delays, including Westinghouse’s bankruptcy in 2017. The total cost of the project to build Vogtle 3&4 is now put at more than $30bn. Georgia Power owns 45.7% of the project; Oglethorpe Power Corp owns 30%; the Municipal Electric Authority of Georgia (MEAG) owns 22.7%; and the city of Dalton owns 1.6%. The units will be operated by Southern Nuclear.
Image: Vogtle unit 4 (courtesy of Georgia Power)