State wants more tower inspections
By BOB AUDETTE, Reformer Staff
Saturday, September 20
BRATTLEBORO — Recent problems with Vermont Yankee’s cooling towers “are totally unacceptable,” stated Vermont Department of Public Service Commissioner David O’Brien, in a letter to the Nuclear Regulatory Commission.
“We need your help in getting to the bottom of these repeated cooling tower failures,” O’Brien wrote Friday, requesting the NRC conduct additional inspections of the system.
Recently, the NRC sent an inspection team to the nuclear power plant in Vernon to determine whether prior cooling tower problems were affecting the operation of a cooling fan cell designed to be available during an emergency.
The NRC has not yet indicated when that report will be available to the public.
“Our special inspection of the cooling tower leakage identified at Vermont Yankee in July is still open,” wrote NRC spokesman Neil Sheehan, in an e-mail to the Reformer. “We are evaluating the most recent event against what we saw during the special inspection.”
On Tuesday morning, a Yankee maintenance worker discovered a 60-gallon-per-minute leak in the pipe that feeds water to the east bank of cooling fans.
Yankee has two banks of 11 cooling fan cells each. In August 2007, one of the 11 cells in the west bank collapsed due to the failure of rotted wooden support members.
Yankee management admitted the collapse was due to shortcomings in the plant’s tower maintenance and inspection program.
During the in-house review, Yankee technicians developed a program to replace certain wooden supports with fiberglass supports.
On Wednesday, Yankee employees identified several wooden beams that required replacement ahead of the schedule created after the August 2007 collapse.
Last month, brackets used to attach the header pipe to new fiberglass supports in the east tower failed, causing a leak of about 100 gallons per minute. The leak was blamed on a faulty bracket design.
“The cooling towers have presented problems over the last two years with leaks due to faulty or degraded materials that comprise the towers,” stated DPS spokesman Stephen Wark, in an e-mail announcing the letter to the NRC. “We are asking the NRC to come back and do additional inspections to determine if this new development impacts safety or the seismically rated cells.”
If there is any “new and significant information,” that arises from this latest leak, wrote Sheehan, the NRC has the option of keeping the special inspection open to further evaluate the cooling towers.
“We’ll review (O’Brien’s) request and respond to it in a timely manner,” wrote Sheehan. “As we’ve noted in the past, our primary focus is on the safety-related cell in the west cooling tower since that could, under some very low-probability scenarios, be needed for the shutdown of the plant.”
One cooling fan cell of the west tower is specially designed to withstand natural disasters such as an earthquake or hurricane. The NRC’s special inspection team came to Vernon to evaluate the safety cell’s integrity in light of the recent problems with the cooling towers.
Entergy, which owns and operates Vermont Yankee, has applied to the NRC to extend the power plant’s operating license for another 20 years, from 2012 to 2032. The NRC has indicated it has found no significant safety or environmental reasons for not issuing the license renewal and is expected to release it final decision in November.
Vermont’s Public Service Board is conducting hearings to determine whether Yankee should receive a certificate of public good to continue operations past 2012. The PSB must decide whether keeping the plant online for another 20 years is in the best interest of Vermonters.
The state Legislature also has the power to prohibit continued operation of the plant.
To inform both the PSB and the Legislature, “a thorough, independent, and public assessment of the reliability of the systems, structures, and components of the Entergy Nuclear Vermont Yankee facility” was authorized by the state.
“Our comprehensive vertical audit inspection team will be looking at the failures from a reliability standpoint through engineering and management assessments,” wrote Wark.
A spokesman for Vermont Yankee said plant managers were working with DPS and the NRC to make sure both agencies get the information they need. The spokesman had no comment on the DPS request for additional inspections.
“The NRC will do what is appropriate,” said Larry Smith. “They’ve been fully briefed on the cooling tower issue.”
The plant was expected to be back up to 100 percent early Friday night.
Original article: http://www.reformer.com/ci_10516112