The Nuclear Regulatory Commission staff has informed Westinghouse that the company has not demonstrated that certain structural components of the revised AP1000 shield building can withstand design basis loads, said David Matthews, director of the commissions Division of New Reactor Licensing.
Part of the NRCs concern is the ability of those buildings to support emergency cooling water tanks that typically hold 6 million to 8.5 million pounds of water more than 100 feet above the ground in addition to being able to withstand seismic and other external events.
The shield building design includes prefabricated steel and concrete modules, he said. This is a situation where fundamental engineering standards will have to be met before we can begin determining whether the shield building meets the agencys requirements.
Although there are seven companies across the country planning 14 new commercial reactors all using the AP1000 design Plant Vogtle is the farthest along , and has been designated as the NRCs AP1000 reference site that will become a model for facilities to follow in the permitting and licensing process.
Carrie Phillips, a spokeswoman for Southern Nuclear, said it is too early to determine if there will be any impact on the Vogtle project.
At this point we dont anticipate any impact with the commercial operation dates for Vogtle Units 3 and 4, which is the 2016 and 2017 time frame, she said. But at this point, until the NRC and Westinghouse review what needs to be done, we dont know what the impact of the schedule might be.
Westinghouse spokesman Vaughn Gilbert said the company is already working to resolve the design issues.
We are completely confident we will meet all the applicable requirements, he said. We expect to continue to work and to receive the design certification amendment in 2011 and we expect to bring the first of the AP1000s in the United States online in the 2016 time frame.
The design changes, he added, are unlikely to cause any delays for clients planning to use the AP1000 reactors.