The US Nuclear Regulatory Commission (NRC) on 27 August released its initial conclusions from the June special inspection at the Vogtle NPP units under construction in Waynesboro, Georgia.
The NRC launched the inspection to understand the cause and extent of construction quality issues in the safety-related electrical raceway system at unit 3.
Georgia Public Service Commission (GPSC) in 2009 approved the Vogtle expansion project, including construction of two 1117MWe Westinghouse AP1000 reactors which were expected to begin operation in 2016 and 2017. The estimated cost of the project was then put at $14 billion. However, recent estimates now put the overall cost at close to $28bn. The project has faced numerous delays and financial challenges over the years, not least the bankruptcy filing by Westinghouse in 2017.
Electrical cable raceway systems are designed and routed to prevent a single event from disabling redundant safety-related equipment in commercial nuclear power plants. These systems consist primarily of conduits and cable trays, which route and support the cables needed to ensure safety-related equipment performs its safety functions.
During the inspection, NRC inspectors reviewed the plant's operator, Southern Nuclear Operation Company’s quality assurance process, corrective actions, and root cause analysis related to the electrical raceway system. They also interviewed electrical craftspeople, superintendents, work planners, field engineers and quality control employees, and reviewed dozens of condition reports, technical evaluations, and work packages.
The NRC inspectors found that Southern Nuclear did not adequately separate safety and non- safety-related cables for reactor coolant pumps and equipment designed to safely shut down the reactor. They also found instances where the company did not identify and report construction quality issues related to the safety-related electrical raceway system and enter them into its corrective action programme.
If finalised at their current level, the findings will increase NRC oversight at the plant. The conditions in the electrical cable raceway system, if left uncorrected, would prevent the plant from operating within NRC’s regulations. However, there is no increased risk to the public while Southern Nuclear corrects the conditions because there is no nuclear fuel in the reactor. NRC will not authorise the licensee to load fuel and operate Vogtle 3 until construction is complete and it has satisfied the standards identified in its combined licence.
Meanwhile, Oglethorpe Power Corporation is now assuming commercial operation dates of June 2022 and June 2023 for Vogtle 3 and 4, the company said in an investor briefing on 25 August. CEO Michael Smith said that while Southern Nuclear and Bechtel are working towards "more aggressive" target dates, the company had "decided to add in an extra layer of conservatism" to both its expected commercial operation dates and budget allocation. Amongst other things, the emergence of the COVID-19 Delta variant has affected on-site progress at the construction project, the company said.
The Vogtle project is jointly owned by Georgia Power (45.7%), Oglethorpe (30%), Municipal Electric Authority of Georgia (22.7%) and Dalton Utilities (1.6%). Other owners include most Georgia electric cooperatives and municipal utilities. Florida’s Jacksonville Electric Authority and some other municipal utilities and cooperatives in Florida and Alabama are also obligated to buy power.
Southern says Vogtle’s 3 is now projected to start operation in spring 2022, while unit 4 is supposed to be finished in 2023 but further delays are possible. The latest revision to the schedule and costs was announced by Georgia Power in July, which was attributed to “productivity challenges and additional time needed for testing and quality assurance”. Georgia Power has agreed to absorb at least $700 million in overruns, but could still ask ratepayers to cover all the other costs. Georgia Power’s 2.6 million customers have already paid more than $3.5 billion toward the cost of Vogtle under an arrangement that’s supposed to hold down borrowing costs. Customers of cooperatives served by Oglethorpe Power have already paid about $400 million, according to Oglethorpe financial statements.