As the crow flies
Sequoyah to Chattanooga: 17.6 miles
Watts Bar to Chattanooga: 48.4 miles
Browns Ferry to Chattanooga: 105.3 miles
Bellefonte to Chattanooga: 41.8 miles
Source: Google Maps Distance Calculator
A third of TVA's six reactors -- one at Sequoyah and one at Browns Ferry nuclear plants -- have been given a bad grade by the U.S. Nuclear Regulatory Commission, according to NRC's newest annual assessment.
And TVA's third operating nuclear plant, Watts Bar, has been flagged by the NRC for a security issue that neither TVA nor NRC is allowed to talk about, according to spokesmen with both agencies.
"As a fleet they have some issues they need to work to correct," said NRC spokesman Joey Ledford. "We believe they are working to correct these issues, and the additional oversight that these plants are receiving should help."
NRC bases its annual assessments of the nation's nuclear plants on inspections and the performance track records of the reactors, according to an NRC blog signed by Kevin M. Roche, the NRC's operating reactor performance assessment leader.
"The NRC program of overseeing this nation's reactors never ends. But the letters give the public -- and the nuclear power plant owners -- a regular report card and, when necessary, the path that will get them back to the honor roll," he said.
TVA acknowledges there are problems.
"While TVA has seen some improvement in overall plant performance over the past year, there is still significant work that needs to be done to accomplish our goal of having all six of TVA's reactors rated as top performing nuclear plants," TVA spokesman Ray Golden said Wednesday.
NRC's safety concerns and ratings are color-coded. A plant operating with no safety problems is coded green.
A white rating is NRC's lowest level of concern, then comes yellow, then red -- the most serious safety flag. NRC steps up oversight with each escalating rating.
Browns Ferry Unit 1 reactor has the nation's fifth red rating ever.
Sequoyah Unit 1 reactor has a white rating.
Watt's Bar's security issue also has a white rating. The plant's assessment letter from NRC states that issue will be "addressed under a separate Security Assessment."
"We want to be in green," Golden said.
TVA's troubled reactors are among 16 nationwide that this year received less-than-stellar reviews.
The nation has 104 operating commercial reactors, and NRC says 88 "fully met all safety cornerstone objectives."
NRC's color ratings also correspond with the columns in an oversight matrix.
Brown's Ferry Nuclear Plant, 105 miles southwest of Chattanooga in Athens, Ala., has the only reactor in what NRC calls its fourth column, the worst rating possible for an operating plant. There is a fifth column, but it is reserved for plants forced by NRC to shut down. In NRC history, no plant has never been in the fifth column.
Brown's Ferry was given its red rating last year after a reactor-core cooling valve failed in October.
TVA and NRC found the valve may have been inoperable for about 18 months. NRC officials said TVA should have been detected problems with the valve long before that time with better testing and maintenance.
In November, NRC placed Sequoyah, in Soddy-Daisy 17.6 miles from Chattanooga, under a white finding because the plant had too many unplanned reactor shutdowns in less than a year. The plant's Unit 1 had four "scrams" between December 2010 and July 2011. It had a fifth unplanned shutdown in August.
In December, TVA disclosed that the NRC had raised the white safety flag at Watts Bar near Spring City, Tenn., for concerns within the security division.
Last year, two contractors were charged with falsifying cable inspection records, but neither TVA nor NRC will say if that played into the security white finding.
Watts Bar Unit 1 reactor is the nation's youngest, operating since 1996, and the plant's new twin reactor, Unit 2, is still under construction.
In January, TVA ordered a safety "stand down" for about 1,000 contract workers for the new Unit 2 reactor after finding that some of those workers had erroneously removed cables from Unit 1 -- the operating reactor.