Federal regulators have raised questions about the safety design of reactor units SCE&G plans to add to its Jenkinsville nuclear plant.
The Nuclear Regulatory Commission wants to make sure the shield building that houses key reactor components can survive a catastrophic event such as a plane crash or hurricane.
"This is a situation where fundamental engineering standards will have to be met before we can begin determining whether the shield building meets the agency's requirements," said Michael Johnson, director of the commission's Office of New Reactors.
The commission, commonly known as the NRC, raised its questions in November and still is waiting for answers from Westinghouse Electric Co., which designed the SCE&G units.
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Westinghouse says it will provide data the commission needs by February.
Cayce-based SCE&G, which is partnering with state-operated Santee Cooper on the $9.8 billion project, believes the commission's questions will be answered satisfactorily.
"After discussions with the NRC and Westinghouse, we continue to be confident that the design will be certified," said SCE&G spokesman Eric Boomhower.Critics say the commission's action could delay the project by months or even years. That could lead to higher construction costs, which customers likely would have to cover, they add.
"It appears there's going to be schedule delays because of problems the NRC has identified with the design," said Tom Clements of Friends of the Earth, an environmental group opposed to the project.
SCE&G, which plans to have the first of two new units in operation by April 2016, cleared a major hurdle in February when the state Public Service Commission OK'd the project.
SCE&G, principal subsidiary of Cayce-based SCANA Corp., and Santee Cooper now are seeking federal approval, which could take another two years.
The power companies now operate one reactor unit at the Jenkinsville site.
The design of the Westinghouse unit - called the AP1000 - is unique for the commercial nuclear power business. It incorporates modular construction and prefabricated parts manufactured elsewhere and shipped to the construction site.
Earlier nuclear plants essentially were custom-built at the site.
Using modular design and prefabricated parts should hold down costs and standardize construction, industry officials said.
As far as the AP1000 that's designed for SCE&G, the shield building will consist of 3-foot thick concrete walls poured at the construction site, said Westinghouse spokesman Scott Shaw.
A reinforced concrete roof then will be assembled on site, lifted in place, and secured, Shaw added.
Inside the building will be a containment shell made of preformed, 3/4-inch-thick steel. The shell will protect key parts such as the reactor vessel, steam generators and coolant pumps.
What NRC analysts aren't sure of is whether the AP1000 design will survive an airborne terrorist attack such as those which leveled New York's twin towers on 9/11.
The NRC's staff has not "analyzed the revised design against an aircraft crash," said spokesman Scott Burnell. "We have to satisfy that before the amended design is approved."
How soon Westinghouse provides the data analysts need will be key to when the NRC finally certifies the AP1000 design, Burnell added.
"We're not going to know where the new end date is until next year," Burnell said.
Boomhower said the Westinghouse design "provides an even safer plant that is more efficient and less expensive to build, operate and maintain. ... We remain confident that our new nuclear project is still on schedule."
Noting that it has been more than 30 years since a new reactor has been ordered in the United States, Clements thinks the NRC is proceeding cautiously because the design is different from anything it has seen before.
"They're basically sailing into uncharted waters," said Clements, who has previously claimed state regulators handed SCE&G a blank check to build the reactor units because construction delays could drive up costs.
State law does allow the utility to seek rate increases to pay interest on money it needs to borrow for the project.
SCE&G estimates rates could climb 37 percent over the life of the project. But it adds covering borrowing costs during the project will save ratepayers $1 billion.
No one knows if delays could drive up costs like they did during a 15-year stretch from the mid-1970s to late-1980s, when the average price of a nuclear plant increased thirty-fold.
Industry officials say delays were partially caused by a two-tier licensing process the NRC used.
Back then, a utility first had to obtain a license to build a reactor unit. Once the plant was completed, the utility had to go back to the NRC and seek a license to operate the unit.
Often, completed units sat idle for years as utilities worked their way through the regulatory maze. The licensing process slowed down further after the 1979 reactor accident at Three Mile Island, Pa., when public opinion swung against commercial nuclear power.
Industry observers believe the public now backs nuclear power, and that regulatory delays have been overcome by the NRC's adoption of a dual-track licensing process. When a utility now wins approval to build a reactor unit, it also will receive an operating permit.
SCANA CEO Bill Timmerman indicated at a recent New York meeting of stock analysts that the company is willing to be patient.
"Frankly, I'm glad they're taking their time in going through this," Timmerman said.