The Nuclear Regulatory Commission put the Sequoyah and Watts Bar nuclear plants on heightened safety review today due to a violation of flood standards, leaving all three of TVA's nuclear plants operating under notices of safety violations.
The NRC said TVA violated safety standards in the way it analyzed and prepared its flood assessment risk for the Sequoyah plant near Soddy-Daisy and the Watts Bar plant near Spring city, Tenn. Both plants are on the Tennessee River.
The NRC staff concluded that TVA did not establish adequate flood protection for the potential failure of upstream dams. The NRC staff has classified that violation as white, meaning it has low to moderate safety significance.
The NRC also found that TVA had not taken necessary measures to prevent water from entering the intake pumping station in the event of flooding. The NRC staff has also classified that violation as white.
The TVA plants also were cited for a violation because TVA did not notify the NRC within eight hours after discovery that the potential failure of the upstream dams and subsequent potential onsite flooding resulted in an unanalyzed condition affecting plant safety.
"TVA has taken adequate compensatory measures at the Sequoyah plant to ensure that the flooding issues are not a current safety concern, but we want to be certain they appropriately address flooding scenarios that could affect important plant safety equipment on a more long-term basis," said NRC Region II Administrator Victor McCree.
The NRC will schedule an inspection to evaluate TVA's corrective actions and TVA must respond in writing with their corrective actions for the reporting violation.
With the violation notice, all there of TVA's nuclear plants are now operating under heightened oversight by the NRC due to safety violations. The Browns Ferry nuclear plant in Alabama was given a red finding in 2011 due to the failure of a safety valve and TVA's failure to recognize the problem.