As ENR previously reported, the project owner had noted that lagging remediation of improperly installed electrical cable raceway systems as a factor in the Unit 3 schedule change.

The two outside monitors—a PSC “staff” team that includes William Jacobs, the state’s independent construction monitor, and a separate Vogtle Monitoring Group, represented by Donald Grace—disagree with the utility’s schedule estimate. Instead, they separately concur in their latest estimates that Unit 3 could likely complete between December 2022 and February 2023, while Unit 4 will achieve that milestone between November 2023 and February 2024.

The recently submitted testimonies of the two monitors offer other assessments of the project’s problems and challenges.

For instance, the Jacobs testimony documents the project’s history of consistent schedule slippage, noting that “the Unit 3 schedule continues to be extended at a rate of nearly one month … per calendar month of work.” In August 2021, for instance, Jacobs noted that Southern Nuclear Co. projected its Unit 3 completion target as June 2022. Just two months later, in October 2021, the company had pushed back that schedule milestone by three months, to September 2022.

The testimony submitted by Jacobs further noted trouble identifying a foundational element of all major construction projects, the critical path, which is “difficult to determine” for Unit 3.

Instead of a single critical path, the monitor says, “Unit 3 has many ‘near critical paths’ … that are within hours of each other, so the primary critical path changes from day to day.” The Jacobs testimony listed eight “near critical paths,” including such items as “completion of construction and testing of the Passive Containment Cooling System” and “completion of electrical rework in the Main Control Room.”

In his testimony, Grace asserted that “the primary root cause of the recently identified construction quality issues is due to SNC not adhering to the principle” of working to a schedule that is both “realistic and understood.”

Both monitors noted the negative effects of an attempt to identify and repair leaks within the Spent Fuel Pool (SFP) that ended up damaging the equipment and requiring months of remediation work.

Jacobs’ testimony noted that to find the leaks, the SFP was filled with water and the system’s leak chases located underneath panel seam welds were pressurized to 30 lbs per sq inch, in the hopes that bubbles would appear, pointing the way to the leaks. When bubbles failed to appear, the testing team’s lead, “without adequate review or approval,” doubled the pressure to 60 pounds per sq inch.

As a result of the air-pressure increase, Jacobs’ testimony reported that “the floor panels became distorted to the extent that they could no longer be used,” requiring the manufacturing of new panels.

On the matter of total project costs, the monitors again differ with the project owner. Grace, for instance, predicts total project costs to range between $20.1 billion and $20.5 billion. Alternatively, Georgia Power’s current cost forecast estimates a total project cost of $19.5 billion.