According to the Chattanooga Times Free Press (http://bit.ly/X1c8jy), TVA must now hire a contractor to look into at least 6,200 shipments of different parts. Some have already been installed and some date to 1995.
It was also unclear Thursday whether some of the parts might also have gone to the Sequoyah Nuclear Plant in Soddy-Daisy, Tenn., and the Browns Ferry Nuclear Plant near Athens, Ala.
TVA officials who met Thursday with regulators in Atlanta said their engineers didn't notice a 1995 requirement change on testing of parts from vendors who weren't nuclear-certified.
The new requirement was put into place when the NRC found nuclear operators were having problems finding nuclear-grade parts as reactor construction lagged following the Three Mile Island accident in 1979. The agency required parts obtained from vendors who did not hold nuclear certification must receive special and strict industry testing and operators must document it.
TVA spokeswoman Gail Rymer said the nuclear plants are safe and the public is not at risk.
Joe Calle, TVA's manager for what the federal utility calls its "recovery project," told the NRC Thursday about 11 percent of the parts have been reviewed. None have been found defective, Calle said.
TVA had no estimate Thursday of how much it will cost to check all the parts, ensure their quality and replace any found substandard.
Calle also said TVA views the situation as a documentation problem and has confidence in the quality of the parts, both because of its history with the vendors and the specifications it provided for the parts.
But he said a drop-down computer menu used by the utility did not have space to make critical notations in records.
"We created our own perfect storm," Calle told the NRC.
Regulatory inspectors first noticed the problem while inspecting Watts Bar in September 2011. A year later, the issue had not been resolved and in February 2012, the NRC gave TVA a "noncited violation" notice.
After inspections in December 2012, January 2013 and February 2013, the NRC increased its oversight, indicating more attention was needed.
Information from: Chattanooga Times Free Press, http://www.timesfreepress.com