published Thursday, December 15th, 2011

NRC flags TVA's Sequoyah nuclear plant over shutdowns

Sequoyah Nuclear Plant is located near Soddy-Daisy.
Sequoyah Nuclear Plant is located near Soddy-Daisy.
Photo by Dan Henry.
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Sequoyah reactor shutdowns
  • Dec. 20, 2010
  • Nov. 16, 2010
  • June 26, 2011
  • July 20, 2011
  • Aug. 18, 2011

Source: TVA

Federal regulators have given Sequoyah Nuclear Plant a "white" safety finding -- the first level of safety concerns that triggers stepped up federal inspections.

Sequoyah, near Soddy-Daisy and 20 miles from downtown Chattanooga, received notice of the finding in a November letter from the Nuclear Regulatory Commission after the plant's Unit 1 reactor had its fourth unplanned "scram" -- or shutdown -- in less than a year.

"This was due to two trips [unplanned automatic shutdowns] in the fourth quarter of 2010, one trip in the second quarter of 2011 and one trip in the third quarter of 2011," wrote Richard P. Croteau, NRC's director of the division of reactor projects.

A fifth shutdown occurred in the reactor after the plant had moved into the white rating, TVA spokesman Ray Golden acknowledged.

White signifies the lowest level of safety concerns, NRC spokesman Joey Ledford said. Red is the highest and in between is yellow.

Neither NRC nor TVA notified the public about Sequoyah's white rating, officials said, but the letter is on file in NRC's online documents database.

TVA officials insist the plant is safe and continues to operate.

"The plant is built to be very safe and, while we are disappointed, we want people to understand that at no point was their safety or employees' safety a problem," Golden said. "We are committed to finding the root cause [of so many unplanned shutdowns] and to making the plant safer. It's a continuing learning process."

Sequoyah is the second TVA plant to have triggered NRC's color-coded safety findings.

The Browns Ferry Nuclear Plant, located 70 miles southwest of Chattanooga in Athens, Ala., received a red finding from the NRC in May. The "red, or high safety significance," finding -- the most severe ranking the Nuclear Regulatory Commission gives to problems uncovered -- is only the fifth issued nationwide in the past decade, according to NRC spokesmen.

Reactors with no highlighted problems in six categories are rated as green and, of the nation's 104 commercial reactors, only about 10 have white, yellow or red indicators. Browns Ferry is the only one currently with a red finding.

  • photo
    Ray Golden, senior manager of nuclear communications for TVA, is seen in TVA's Chattanooga office complex.
    Photo by John Rawlston /Chattanooga Times Free Press.

Ledford said the NRC guideline is that a reactor can have three unplanned shutdowns in 7,000 operating hours.

"With [Sequoyah's] fourth one, they crossed the green-to-white threshold," he said, adding that NRC now plans a special weeklong inspection, probably in February at the plant.

"Right now, there is no indication the scrams are related, but TVA will be looking at the root causes and we will look at all of that," he said.

"We're not pleased with that [having two plants with safety issues], but we are working on it," Golden said. "Hopefully soon we'll have one back in the green space. But the bottom line for the public is this: We know we operate for their trust."

Sandy Kurtz, an anti-nuclear TVA critic in Chattanooga, was not pleased to learn of the new safety concerns at Sequoyah.

"It's good to know that the safety mechanisms [of shutdowns] kicked in, but the concern is why did they have so many in a short time," she said.

Yvonne Derrickson, who has lived near the Sequoyah plant for 25 years, said the news worries her.

"I am concerned," she said. "Even though there hasn't been an accident, when there is an accident, it's devastating. I'm hoping we can find alternative energy sources."

Daniel Cobb, a retiree who for 16 years has lived about a mile from Sequoyah, said he is "perfectly comfortable" living close to the plant, but he expects "somebody will have to buckle down and fix it."

"A lot of people I know get upset about it, [living near a nuclear plant]. But the fact is, where I live right now and where you are -- you'd probably live 40 seconds longer than I would if something happened," he said.

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about Pam Sohn...

Pam Sohn has been reporting or editing Chattanooga news for 25 years. A Walden’s Ridge native, she began her journalism career with a 10-year stint at the Anniston (Ala.) Star. She came to the Chattanooga Times Free Press in 1999 after working at the Chattanooga Times for 14 years. She has been a city editor, Sunday editor, wire editor, projects team leader and assistant lifestyle editor. As a reporter, she also has covered the police, ...

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rolando said...

You can bet your life I am deliriously happy that the system works...the safeties functioned as designed and shut the place down. Kudos to the designers for their excellent work.

Tripping -- even if false -- is infinitely better than having one of the things fail to trip when it should have, as happened at Watts Bar.

Keep that in mind, Fed Inspectors, before you start sticking your noses in there and screwing the pooch for all of us.

December 15, 2011 at 9:16 p.m.
GarryMorgan said...

What you do not say "rolando" is very important.

1) A "turbine trip" resulted in a reactor scram, an emergency shut down, it seems the event referenced is the one which occurred on Jun 26, 2011. A turbine trip, NRC event # 46991. 2) The analog electro-hydraulic control signal conditioning card failed causing an indication that the main turbine had tripped resulting in the governor and throttle valves closing. 3)The Control Room Operators misdiagnose the reason for control rod insertion and incorrectly placed control rods in manual. 4) The steam dump system was manually turned off because three of the valves did not close when expected. Result, decay heat removal was via the steam generator atmospheric relief valves.

What does this mean? Either non-attentive or unskilled operators were at the controls of an atomic reactor. They misdiagnosed a problem. Which was an antiquated analog electronic part which failed. Specifically the analog electro-hydraulic control signal conditioning card. The steam dump system was shut down which resulted in a release of radioactive contaminants into the atmosphere. Worse, the TVA has said nothing about the radioactive contaminant release to the public.

This says much about the TVA's nuclear program and management of the program. They are spending billions on the Bellefonte Reactor completion and millions on small modular reactor project research.

To finish Bellefonte the TVA must sell part of their electrical power generation assets. All the while the TVA neglects upgrading existing assets and properly training personnel. Analog systems - TVA is operating on the basis of antiquated technology and deceitful management, a dangerous combination. The results, failures such as the nuclear event on Jun 26, 2011 at the Sequoyah nuclear reactor. Other failures: Kingston, Widows Creek, Browns Ferry; who knows what other problems in which the public is unaware.

The Dec 10, 2010 fire, NRC event 46492 is suspicious in its report. I've never seen a fire adhere to a specific time table to avoid an emergency from being declared. There is a conflict in the event report as to time of the event and the narrative report time of the events begining. The fire cause was identified as a hydrogen leak that ignited in the bus duct housing of the main generator which resulted in the reactor scram.

Another tidbit of information, 3 of the events which resulted in the scram of reactor #1 occurred between the 2 hour period of 9-11PM. Significant, depends, all of the events occurred after 4PM and up to shortly after midnight. I'm wondering if management is assigning inexperienced crews on the evening and later shifts?

"White safety finding," the NRC is being kind. Should be at least a "yellow safety finding."

December 16, 2011 at 11:07 a.m.
Gloats said...

Oversight by NRC & TVA reminds me of monkeys...see no, hear no, speak no evil.

December 16, 2011 at 5:30 p.m.
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