ATLANTA — Missing quality-control documentation is one of the biggest reasons that construction of two nuclear reactors at Plant Vogtle is falling behind schedule, according to testimony Tuesday at the Public Service Commission.

The comments came from William Jacobs, a nuclear engineer the commission hired with Georgia Power Co. funds to monitor the construction. He testified that a Louisiana subcontractor making components for the reactors was new to the nuclear field and wasn’t accustomed to the requirements to document ever step in the fabrication process. He said the company had promised changes in personnel and procedures to correct the snafu, which took eight months for one of its modules that still hasn’t been shipped to the Waynesboro plant.

“It happened month after month. We would go to meetings, and they would present all the ‘new and wonderful things’ they were now doing differently, and then the next month there’d be more new and more wonderful things. Yet, no modules were arriving at the (construction) site,” he said. “It’s been a painful process.”

He said the company has finally resolved the situation but that it delayed construction by 15 months in the meantime.

Commission Chairman Tim Echols said after eight months, the module could have simply been rebuilt with the correct records.

“Do you know how difficult it would be to stand in front of ratepayers and others and say, ‘the reason the project is over budget is because of paperwork?’” Echols said.

The commission is reviewing what Georgia Power spends every six months on construction and can block the utility from passing along expenses to customers that are “clearly imprudent.” Jacobs has pointed out delays and budget overruns, but so far the commission hasn’t disallowed any expenses. He noted that under the construction contract the utility can assess penalties on the builder for missing its schedule.

Before Jacobs’ testimony, a parade of private citizens opposed to nuclear power took turns urging the commission to halt construction to prevent customers from being saddled with the costs.

“What I understand from the testimony of Georgia Power and William Jacobs, this project is on the path of financial failure,” she said.

In related testimony earlier this month, PSC consultant Philip Hayet — an expert on cost modeling and utility industry policy — questioned Georgia Power’s forecast of $5 billion in economic benefits from the Vogtle project.

“Staff believes this figure is misleading and requires further clarification,” he wrote, noting that the $5 billion figure is from a “cost to complete analysis” but does not represent the project’s impact to ratepayers.

Issues with late delivery of components, the need to correct non-compliant rebar and other factors are lining up to create 12- to 18-month delays in completing the projects, which in turn will further reduce the perceived economic benefit to ratepayers, he said.

“The impact of the 12-month delay is a reduction in benefits of about $1 billion, while the 18-month-delay scenario results in about an additional reduction of $300 million in benefits,” he said.