The Nuclear Regulatory Commission (NRC) has identified a problem with loose bolts used for HVAC ductwork during construction of the Mixed Oxide Fuel Fabrication Facility in South Carolina, sending as a result a notice of violation to project contractor CB&I AREVA MOX Services.
The MOX facility is being built to convert 34 metric tons of U.S. nuclear weapon-usable plutonium into commercial nuclear fuel.
The Feb. 2 letter noted that during an October-December 2016 NRC inspection the project contractor continued work on the MOX Processing Building – to be used for blending, milling, fuel rod fabrication, and related work – and the Aqueous Polishing Building, which will remove impurities from the feed plutonium. Inspectors found that construction activities were generally performed safely.
Still, the NRC identified one Severity Level IV violation of its requirements – which is of lesser significance than Level I, II, and III violations and involves no civil penalty – for which it issued a notice of violation.
The notice said ductwork fabrication and installation quality rules call for bolts to be “snug tight and provide for even compression of the gaskets.” From December 2015 to October 2016 the contractor fell short of that specification, it said, “in that bolts used in assembling HSA ductwork in Room B-360 were found to be less than snug tight after final assembly.”
“Specifically, at least one bolt was found to spin freely by hand alone,” the notice said, adding that this violation was repetitive due to the lack of prior corrective action on the problem.
NRC inspectors last March identified loose bolts on flanged connections for safety-related HVAC supply air ductwork; the bolts had been installed but not tightened to specifications, the notice said. This “resulted in an adverse impact to the quality of the construction of safety-related components,” according to the NRC. Months later, when the inspectors revisited the ductwork, they found that the bolts still did not meet specifications – the latest notice is a result of that finding.
The contractor must submit a statement to the NRC within 30 days, including the reason for the violation or a basis for disputing it, corrective steps taken and those that will be taken, and the date by which full compliance will be reached.
In 2014 the contractor reported to the NRC that faulty welds caused cracks in HVAC filter housings supplied for installation at the MOX facility; it also said that none of those faulty components were installed and that it would work with the vendor to ensure all welds meet quality standards.
