Entergy Vermont Yankee is working to plug a pinhole leak on a one-inch drain line. The leak is located in a safety-related system used to inject water into the reactor if the plant suddently shuts down.
The leak was discovered on September 24 when an operator, during normal rounds, observed a puff of steam coming off a drain line in the High-Pressure Coolant Injection (HPCI) system, said Neil Sheehan, a regional spokesman for Nuclear Regulatory Commission.
"That system would be used if the reactor had to shut down suddenly. Since high pressure levels would remain inside the reactor vessel, the HPCI system can be used to inject water inside despite those conditions," said Sheehan. "The system, and the drain line, are located inside the reactor building. As such, any leakage is captured by a sump and sent to a radioactive liquids treatment system."
Despite the location of the leak, the NRC and ENVY consider it to be of "low safety significance." Only after media inquiries did the leak become public knowledge.
"It's of low safety significance because it's a small leak on a one-inch drain line and does not affect operability of the HPCI system or, more broadly, the plant. In other words, the HPCI system could continue to perform its function despite the leak," said Sheehan.
Sheehan was unsure if the plant will have to power down in order for a repair to be made.
ENVY has been in the process of determing the source of the leak, and how to repair it. ENVY tried to fix the leak October 6, but could not get good steam isolation on the system without going into the steam tunnel, said Sheehan. Therefore, the company decided to halt the effort and rescheduled it for Oct. 15.
Then, ENVY discovered it was not a weld on the pipe that was leaking but the pipe itself, and a different repair plan would have to be put together, Sheehan said.
Entergy spokesman Larry Smith said the plant would not likely have to power down to fully repair the leak, but he'll know more soon. The company is trying to determine whether to patch or replace the drain line. In the meantime, the safety-related system is operable as there are other pipes that can provide the necessary injection of water, if needed.
"Right now we have a maintenance patch in place," said Smith. "There is no risk to worker safety or public health. The leak is just wisps of steam. Any condensation is collected in sump pumps and circulated right back into the reactor."
The NRC's Resident Inspectors remain "on top of the issue and will continue to monitor the company's repair efforts," added Sheehan.
News of the plant leak comes just weeks after low levels of tritium were discovered in an onsite drinking well at Vermont Yankee. The drinking well was taken out of service earlier this year when much higher levels of tritium were found in the nearby groundwater.
Earlier this year it seemed as if every week VY was announcing a new leak at the aging reactor.
Vermont Yankee remains a hot button campaign issue — especially in the governor's race — with Democrat Peter Shumlin supportive of shutting down Vermont Yankee as scheduled in 2012 and Republican Brian Dubie supportive of keeping VY open another 20 years if state regulators say it's safe.
A so-called 527 lobbying group, Green Mountain Futures, has been running ads since September criticizing Dubie's stance on Vermont Yankee. So far, theirs is the only campaign countering Entergy's own PR efforts — IAMVY.com and VT4VY.com. The former includes testimonials from VY employees about the plant's safety and the latter is from business owners who tout VY's low-cost power and economic impact.
Entergy officials will not say how much they are spending on their advertising campaign.
Green Mountain Futures reported raising $533,995 since it launched in early September. Of that, it's spent about $430,000. The lion's share of the money is coming from the Democratic Governor's Association. The DGA supplied all but $20,100 of the group's funding, according to a report filed with the Internal Revenue Service.
In addition to the DGA cash and in-kind contributions, David Blittersdorf of AllEarth Renewables, donated $20,000 and a single individual from Barre donated $100. Blittersdorf has been a long-time supporter of Shumlin's, and hosted his formal campaign kickoff at his Williston business.
News of the leak also came the same day that Public Service Commissioner David O'Brien told the industry group's annual meeting that VY should be relicensed.
"Vermont Yankee is safe, the Nuclear Regulatory Commission says so," O'Brien told the crowd of 150 manufacturers and other business leaders attending the annual meeting of Associated Industries of Vermont. "The plant scores highly in industry peer review, and its problems, although well publicized, do not pose health concerns."