The plant produces prefabricated wall and floor sections, called structural submodules, for the CA20 module, a component of the AP1000 reactor design being constructed at both Plant Vogtle and V.C. Summer. The submodules measure as wide as 8 ft, as high as 12 ft and as long as 69 ft and weigh up to 44 tons, according to Georgia Power officials.

William Jacobs, the Georgia Public Service Commission's independent construction monitor for the Vogtle project, has cited the plant's failure to produce a sufficient quantity and quality of materials as one factor slowing the project's progress.

In 2013, Georgia Power—and the other utilities partnering as owner— implemented a stop-work order for the Lake Charles plant. Currently, the project owner "continues to aggressively monitor the contractor's review process for release of submodules," says Georgia Power spokesman Brian Green.

"Significant progress has been made in this area," Green adds. The utility credits the progress to CB&I's decision to inspect and repair all remaining CA20 submodules at the Vogtle site.

Also, while the Lake Charles facility is continuing to fabricate some Unit 4 CA20 submodules for the Vogtle project, Georgia Power and its owner partners have contracted out structural module fabrication for certain Unit 4 modules to four other vendors, Green says.

Georgia Power is officially targeting a commercial operation date of late 2017 for Vogtle's Unit 3 and late 2018 for Unit 4. But that could be a challenge.

Jacobs told commission officials in June that builders "face many challenges" in meeting the current operation deadlines and will need to implement successfully numerous as-yet-unidentified mitigation strategies in order to maintain that schedule.