Mistakes by construction workers at the Tennessee Valley Authority’s Watts Bar reactor project, described last Friday by the utility’s chief executive as potentially fatal, idled about 1,000 workers temporarily for a safety talk.
TVA ordered an unpaid safety work stoppage at the reactor project between Chattanooga and Knoxville in response to finding this month that cables were erroneously removed in December from the plant’s operating Unit 1 reactor and discovering that a valve in the Unit 2 reactor now under construction was improperly removed from another system.
A TVA spokeswoman told the Chattanooga Times Free Press that the construction “stand down” ordered to start at noon Wednesday was to continue “until the errors discovered are clearly communicated to all personnel.”
TVA spokeswoman Barbara Martocci said no one was hurt and at no time was there a risk to public safety. She said construction at the $2.5 billion, 1,200-megawatt Unit 2 reactor project, which is expected to be completed in 2013, would resume on Monday.
Martocci said TVA had not yet determined if the mistakes were due to carelessness but a “root cause analysis” was being conducted.
“We don’t recall doing a stand down like this,” she said Friday.
TVA’s top executive, Tom Kilgore, said in a statement to employees on Friday that “when workers return to the site on Monday, they will join foremen and supervisors to review an error that occurred in December that had the potential for fatal consequences and that was identified earlier this week at Watts Bar Unit 2. Also to be reviewed is a second incident that occurred this week which could have resulted in a severe injury or worse if it had happened under slightly different circumstances.”
Nuclear Regulatory Commission Region 2 spokesman Roger Hannah said Friday that such work stoppages at nuclear plants are “not uncommon” and probably occur every two or three years. Hannah said they are “not exclusive to the nuclear industry.”
Hannah declined to speculate about any possible penalty for TVA.
He said TVA would assess both nuclear safety and workplace safety issues.
The NRC has inspectors at Watts Bar, where the Unit 1 reactor is the nation’s newest, operating since 1996.
“We’ll look at what happened,” Hannah said. “It could lead to some follow-up inspection.”
The problems were discovered in routine TVA inspections and follow heightened NRC scrutiny on other TVA nuclear plants.
NRC last summer placed TVA’s Browns Ferry plant near Athens, Ala., under a red finding _ the regulator’s most serious safety flag. In November, NRC placed the Sequoyah Nuclear Plant near Chattanooga under a white finding, the lowest safety rating, because the plant had too many unplanned reactor shutdowns in less than a year. Under NRC’s color-coded inspection findings, white is least serious, then yellow, then red. A plant operating with no safety problems is coded green.
Two contractor employees at the Watts Bar project were charged last year with falsifying electrical cable inspection records.
Martocci said Friday that TVA did not notify the media or provide public notice on Wednesday because “it doesn’t affect people on the outside. It affects our employees.”
“We had information available if people had called us and asked,” she said.
David Lochbaum, director of the Nuclear Safety Project for the Union of Concerned Scientists, said the incidents involved little-used, redundant systems that only in worst-case scenarios might have tripped a reactor. But he agreed with TVA’s action to get workers’ attention.
“It’s the right thing to do. It’s like a timeout for workers to refocus,” said Lochbaum, a former TVA nuclear operator and a former NRC training instructor.
TVA supplies power to about 9 million people in Tennessee, Alabama, Mississippi, Kentucky, Georgia, North Carolina and Virginia.