There was a “breakdown” in a quality assurance program designed to ensure the safety of commercial parts used in a nuclear reactor under construction, the Nuclear Regulatory Commission (NRC) said in a report.
There were three apparent violations of agency rules for dedication of commercial parts for use in the Tennessee Valley Authority’s (TVA) 1,100-MW Watts Bar-2 nuclear generating unit in Tennessee, NRC officials said. The apparent violations will go under review to determine how serious they are, but initial estimates show it is a problem that could result in additional inspections and fines, the NRC said in the inspection report.
TVA is reviewing all commercial-grade parts used at Watts Bar-2 and so far has found no case where a part could not have met its safety function, said spokesman Duncan Mansfield. The issues raised in the NRC report do not pose a safety threat to workers or the public and will not affect the federal power producer’s plans to bring the unit online around December 2015, he said.
TVA representatives said during a meeting with NRC officials in Atlanta last week the commercial-grade dedication failing extended to its six-unit operating nuclear fleet and it is reviewing thousands of parts already installed in plants to ensure they will meet their safety function.
Nuclear reactor operators usually purchase safety-related equipment from suppliers holding nuclear-grade manufacturing certification under standards organizations like ASME. But as vendors have let those certifications lapse because of a lack of nuclear construction over the past several decades, nuclear plant operators in the U.S. have relied more on commercial-grade equipment that is then dedicated, or qualified, for a safety purpose, TVA officials said during the meeting.
TVA recognizes there was a significant problem in the use of commercial-grade parts, said Don Jernigan, senior vice president for nuclear support services.
The federal power producer in 2011 revised procedures for commercial-grade dedication to take into account NRC concerns, and is conducting a review of commercial-grade parts acquired by TVA’s nuclear fleet as far back as 1995, he said. That review has not found any defective parts directly connected to the commercial-grade dedication lapses, another TVA official said.
NRC said an earlier inspection revealed deficiencies in the commercial-grade dedication program at Watts Bar-2, which TVA is completing after having suspended construction in the 1980s. A review by TVA following that inspection “suggested that the problems with [commercial grade dedication] were pervasive enough to indicate a breakdown in the program resulting in multiple examples of construction of unknown quality,” NRC said in the report.
The regulator said the breakdown was an apparent violation of NRC requirements, as were the failure to report the quality-assurance failings and an inadequate evaluation of the issue when initially responding to it. The NRC will likely rank the three apparent violations in the top three of its four severity categories for violations, the report said.
TVA may request a conference at which it can dispute the existence and the severity level of the violations.