• Brown's Ferry construction began in 1966 and the plant began operating in 1974.
• In March 2002, Brown's Ferry Unit 3 reactor finished the longest unbroken operational run of a TVA nuclear unit and the second-longest among all U.S. plants. It ran nonstop for 669 days before going off-line for a scheduled refueling outage, generating a world-record 18 million megawatt hours during that time.
Source: Tennessee Valley Authority
TVA officials say increasing federal oversight of the Browns Ferry Nuclear Plant will cost the utilities and ratepayers "in the millions of dollars."
The statement came after TVA lost its appeal of federal regulators' dire safety report in May over a failed cooling valve at Browns Ferry, located in Athens, Ala.
Because of the report, the Nuclear Regulatory Commission said it will send teams of inspectors into the plant to review TVA's inspection and safety culture.
In early May, the NRC concluded that last fall's failure of a cooling-water injection valve at the plant - along with the revelation that the valve may have been inoperable for more than 18 months - was a rare red-level finding of "high safety significance."
Only five such "red" findings have been issued since 2001.
"We disagreed with the assertion that TVA has a deficient inspection program," said TVA spokesman Ray Golden. "And in our appeal, we said if TVA's program is deficient, it is like all other inspection programs [required by NRC.]"
NRC's denial letter, signed by regional administrator Victor McCree, acknowledged that question may need further review and the Browns Ferry event may have future implications for the industry.
"The NRC recognizes the potential generic implications associated with this issue and has initiated actions to address this issue separately," McCree wrote.
Golden said TVA doesn't disagree that the nonworking cooling valve is a significant issue and the utility looks "forward to the opportunity for additional dialogue" with NRC.
NRC spokesman Roger Hannah said TVA will be charged for the inspectors' time and stepped-up oversight, as well as the cost of any retrofits eventually required.
Hannah said the inoperable valve caused concern.
"One of the things we do as regulatory agency is look at safety systems," he said. "I don't want to say we don't look at money, but our mandate is to look at the safety of the plant, and that's something we don't compromise on."
Golden said TVA has assembled a team to address the issues and work with the NRC, but the additional manpower and work will be costly.
"On the other hand, if it means we have less reactor trips [shutdowns] and a better fire protection program, in the long run it will pay for itself many times over. But it's the right thing to do."
NRC officials said the stuck valve meant water usually used for fire safety had to be routed to cool the reactor for several days. That would have been a problem in the event of a fire.
Browns Ferry is known as the site where a worker using a candle to check for air leaks in 1975 started a fire that disabled safety systems.
Browns Ferry's design is similar to the reactors that malfunctioned at the Fukushima Dai-ichi nuclear plant in Japan after a powerful earthquake and tsunami.