Revised in-service dates for Vogtle units

Friday, 17 February 2023

In January, Southern subsidiary Georgia Power notified the US Securities and Exchange Commission that Vogtle 3's initial criticality would be delayed after vibrations in the plant's cooling system were found during start-up and pre-operational testing. Speaking in the company's fourth quarter 2022 earnings conference call yesterday, Fanning said the vibration issue has now been remediated and testing has resumed, but "during this work we identified a few additional issues to address."

"Consistent with our focus on optimal long-term performance - and getting it right - we've added some time to the unit 3 schedule to address these items and to reduce the risks associated with other potential issues emerging," he said.

The vibration issue was remediated by inserting metal plates into struts connected to the pipe, a straightforward fix but one which took time, Fanning said. The second issue - a dripping valve - was also easily remedied by repositioning a flange associated with the valve.

The third issue concerns flow rates through reactor coolant pumps, Fanning said, and is now being investigated. This could be a physical issue, or one related to the calibration of flow measurements, he added.

Lessons learned from unit 3 are being applied to unit 4, so the same problems are not expected to occur when the second unit enters the testing phase.

Fanning said that although the company could have moved ahead with the startup programme at unit 3, it preferred to fix issues before criticality is reached. "The purpose of the test voyage is to find problems - we allow for that within the schedule," he said. "We now have added another month into our projection."

The company's timeline now sees unit 3 reaching first criticality in March or April and "in service" in May or June.

All the systems required for the start of hot functional testing at unit 4 are complete, Fanning said, and with a "marked improvement" in testing results for unit 4 compared to unit 3. Although margin is built into the schedule, however, and its experience at unit 3, the company is "further risk-adjusting our unit 4 schedule to reflect a range of projected in-service dates between later first quarter of 2023 and the end of the first quarter of 2024."

Hot functional testing of unit 4 is expected to begin during March, with fuel load in June.

"Our priority remains bringing Vogtle units 3 and 4 online to provide Georgia with a reliable, carbon free resource for the next 60 to 80 years. We will continue to take the time needed to get it right, and will not sacrifice safety or quality to meet schedules," Fanning said.

Construction of Vogtle 3 began in March 2013 and unit 4 in November that year. The two AP1000s are the first new nuclear units to be built in the USA in over three decades. The units are co-owned by Georgia Power, Oglethorpe Power, MEAG Power and Dalton Utilities, and will be operated by Southern Nuclear.

Georgia Power's share of the total capital cost forecast is USD10,593 million and its estimated cost to complete the project is USD1,072 million.