By Roberta Rampton
WASHINGTON (Reuters) - The U.S. nuclear safety regulator is weighing whether the latest nuclear reactor design should be subject to another public comment period after it asked the manufacturer to resolve technical issues in its application.
Calling for public comments on Westinghouse's AP1000 reactor could throw off the schedule for the reactor the industry was hoping would help kickstart expansion of the sector that has not seen a new reactor built in 30 years.
Loss of confidence in the new design would deal another blow to U.S. nuclear power after the Japanese disaster at Fukushima shook confidence in the industry worldwide.
Comment periods run for at least a month and often longer, after which staff must analyze and respond to concerns raised.
"The NRC right up to the chairman are considering" the idea of opening the design to another comment period, said Perry Buckberg, a senior project manager with the Nuclear Regulatory Commission, during a meeting about the reactor on Thursday.
The NRC had planned to finalize its rule approving the AP1000 design by fall. The new schedule is not yet clear, Buckberg said.
The AP1000 is part of pending applications for new reactors planned by Southern Co and SCANA Corp, and other U.S. companies also want to build the reactors.
The original comment period on the AP1000 ran for 75 days, ending May 10, and garnered more than 13,000 comments. Nuclear critics have been pushing the NRC to slow the new reactor.
WESTINGHOUSE: MINOR ISSUES
Last month, NRC Chairman Gregory Jaczko issued a statement flagging technical issues with Westinghouse's application for the AP1000, a new type of reactor with safety systems that don't require pumps and electric power for forced cooling during power blackouts.
Loss of power to Japan's Fukushima plant after the March 11 earthquake and tsunami led to a meltdown of the reactors, and officials are still working to contain the disaster.
The technical issues are not related to the NRC's inquiry into Fukushima, and came to light beginning in December.
Westinghouse, majority owned by Toshiba Corp and Shaw Group, believes the issues raised with its application to the Nuclear Regulatory Commission are minor.
The company has revised its calculation of the peak pressure the containment unit of its reactor would face during an accident, and the NRC wants more information about the revisions, said Rolf Ziesing, the company's licensing manager.
"There is no design change. There is no concern with the design. What we are talking about here is making some minor corrections to the supporting analysis documentation to substantiate the correct calculated pressure," Ziesing said during the public portion of a meeting with the NRC.
The reactor is designed to withstand pressure of 59 pounds per square inch. In December, Westinghouse had calculated the peak pressure that an accident could create would be 57.8 psi, but it has since revised that up to 58.3 psi.
The revised peak pressure is still below the limit of 59 psi, meaning design changes aren't required, Ziesing said.
(Editing by Russell Blinch and David Gregorio)