The motor fault in one of the unit's four reactor coolant pumps - or RCPs - was discovered during start-up and pre-operational testing, Georgia Power said in a filing to the US Securities and Exchange Commission (SEC). The process to replace the pump with an on-site spare has already begun. "Considering this remediation and the remaining pre-operational testing, Georgia Power projects that the Unit 4 in-service date will occur during the first quarter 2024," it said. Previously, the in-service date had been pencilled in as late this year or early in 2024.
The four RCPs at Vogtle 3, which is now in commercial operation, have operated as designed, so plant operator Southern Nuclear believes that the motor fault on the RCP at Vogtle 4 is an isolated event, the companies said. The projected schedule for Vogtle 4 "primarily depends on the continued progression of pre-operational testing and start-up", it added: "As testing continues, new challenges also may continue to be identified, which may result in required engineering changes or remediation related to plant systems, structures, or components (some of which are based on new technology that only within the last few years began initial operation in the global nuclear industry at this scale). These challenges may result in further schedule delays and/or cost increases."
Dispute settled
In the same SEC filing, Georgia Power and its parent, Southern Company, announced the agreement with Oglethorpe Power to resolve a dispute regarding cost-sharing and tender provisions of the joint ownership agreements relating to Vogtle units 3 and 4. Georgia Power has agreed to make a payment of USD308 million to Oglethorpe for a portion of Oglethorpe's previously incurred construction costs, as well as paying a portion of Oglethorpe's further construction costs for the units - around USD105 million - based on the current capital cost forecast. It will also pay 66% of Oglethorpe's costs of construction with respect to any amounts above the current project capital cost forecast. The parties have agreed to dismiss pending litigation on this issue, including counterclaims by Georgia Power.
Georgia Power resolved a similar dispute with another of the plant's co-owners, the Municipal Electric Authority of Georgia (MEAG Power) in September 2022. Similar litigation with the other co-owner, Dalton Utilities, is still pending.
Construction of the two Westinghouse AP1000s began in 2013. Unit 3 - the first new reactor to start up in the USA since 2016 - reached first criticality in March this year and was declared in commercial operation in July. Fuel loading at unit 4 began in August.
Plant Vogtle is jointly owned by Georgia Power (45.7%), Oglethorpe (30%), MEAG Power (22.7%) and Dalton Utilities (1.6%).
