The Nuclear Regulatory Commission has put the Sequoyah and Watts Bar nuclear plants on heightened safety review after plant designers and operators violated flood safety requirements for the riverfront plants.
The NRC citation issued Wednesday means that all three of TVA's nuclear plants are now operating under extra regulatory review for the first time since the federal utility idled its entire nuclear fleet in the 1980s.
In a notice published Wednesday, 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. 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 at the plants.
But Victor McCree, regional administration for the NRC in Atlanta, said TVA has taken "adequate compensatory measures to ensure the flooding issues are not a current safety concern" and no civil penalty will be imposed beyond TVA having to pay the NRC for the expense of the extra inspections and oversight.
TVA spokesman Duncan Mansfield said utility officials take the deficiencies uncovered by NRC inspectors "very seriously and have taken steps to immediately address many of the conditions" though temporary earthen dams and extra weather monitoring equipment. TVA is planning to build new seismically-reinforced buildings above the worst projected flood levels to house some backup safety systems, although the new buildings have yet to be designed and may take several years to complete.
TVA discovered the flood risk to Sequoyah and Watts Bar while calculating potential flood dangers at the Bellefonte Nuclear Plant under development in Alabama, also on the Tennessee River. New calculations show flooding would rise more than four feet higher than Watts Bar was licensed and designed to handle.
"TVA will continue to cooperate with the NRC to implement additional corrective actions," Mansfield said.
But Louise Gorenflo, a member of the Sierra Club and the Bellefonte Efficiency and Sustainability Team (BEST), said TVA violations of NRC standards at Watts Bar, Sequoyah and previously at the Browns Ferry plant indicate "TVA is repeating its experience in the 1970s of not having a handle on a very dangerous technology and not taking responsibility for the danger that they present to the public." In 1985, after repeated safety problems were uncovered, TVA shut down its entire nuclear fleet and subsequently spent billions of dollars and more than five years fixing and upgrading the plants.
"These problems certainly don't speak well of TVA as the national model it was designed to be for our country," Gorenflo said.
TVA will operate under the heightened NRC review at Sequoyah and Watts Bar through at least the rest of this year.
NRC spokesman Roger Hannah said the nuclear accident at Japan's Fukushima Dai-Ichi plant in March 2011 focused more attention on the risks of flooding plant equipment.
TVA already estimates it will spend $225 million to $250 million to inspect, upgrade and document its three operating plants to come into compliance with new safety standards adopted in response to the Fukushima accident.
Contact Dave Flessner at email@example.com or at 757-6340