Vibrations detected during pre-operational testing at unit 3 of Georgia Power’s Vogtle NPP in the US are likely to further delay start-up of the unit. The vibrations, associated with some piping within the cooling were identified by Southern Nuclear Operating Company. Georgia Power, a subsidiary of Southern Co, is currently building Vogtle units 3 & 4, in Waynesboro Georgia. They will be the first new nuclear units built in the US in more than 30 years.

"Southern Nuclear expects to file a licence amendment request with the US Nuclear Regulatory Commission (NRC) to help expedite the remediation," Georgia Power said. The company said it expects initial criticality will occur in February, and that unit 3 will enter service during April instead of March as previously planned.

Georgia approved the Vogtle expansion in 2009 and the Georgia Public Service Commission approved the new reactors in 2012. At that time, the two 1,117MWe Westinghouse AP1000 reactors were expected to cost about $14bn and to enter service in 2016 and 2017. Construction of Vogtle 3 began in March 2013 and unit 4 the following November.

Analysts estimate total costs, including financing, have now increased to more than $30bn following delays related to the 2011 Fukushima accident in Japan, the 2017 bankruptcy of former contractor Westinghouse, and the coronavirus pandemic. NRC’s approval to begin fuel loading in October 2022 had been delayed because much of the reactor's wiring had to be redone after federal regulators found major flaws. Southern Co also fell behind on inspection documents that had to be completed before the NRC could sign off.

Extending the in-service date for unit 3 beyond the first quarter of this year "is estimated to result in additional base capital costs for Georgia Power of up to $15m pretax per month, as well as the related allowance for funds used during construction and any additional related construction, support resources, or testing costs," the company said.

Units 1 and 2 at Plant Vogtle have operated since 1987 and 1989. Georgia Power owns 45.7% of Plant Vogtle. Three other project partners — Oglethorpe Power Corp, the Municipal Electric Authority of Georgia (MEAG), and the City of Dalton Utilities — own the other 54.3%.

Image: Vogtle Nuclear Plant Unit 3 (courtesy of Georgia Power)