The Vermont Yankee nuclear power plant is operating at reduced power due to problems with the condenser tubes, which are reported to be leaking. Most nuclear power plants replace their condenser at between 20 and 30 years of continued operation, while Vermont Yankee’s condenser been in operation over 39-years.
Condenser leaks adversely affect reliability and the water quality of the water that is used inside the nuclear plant as the primary reactor coolant. Cooling for the plant’s steam condenser is provided from the adjacent Connecticut river. At the beginning of February, nuclear engineers at the plant discovered that the condenser was not operating efficiently. There have been a string of outages in recent months that Yankee has had to reduce power because of problems with the condenser.
Condensers have been known to fail catastrophically, as occurred at Entergy’s Grand Gulf Plant, shutting down the plant for several months. Thus failure of the Condenser would have a tremendous impact upon Vermont Yankee’s ability to operate within cost-effective margins. The condenser has thousands of small tubes, that are made out of admiralty metal, copper, stainless steel, or titanium. The Condenser has two major functions:
- Condense and recover the steam that passes through the turbine (Condensers are used in all power plants that use steam as the driving force)
- Maintain a vacuum to optimize the efficiency of the turbine.
A regional spokesman for the NRC said the plastic coating Entergy used on the condenser tubes has caused the system to run less efficiently. If the epoxy is the source of the issue, the plant will have to run at 50 percent power levels while workers strip epoxy off of the tubing in each of the sections of the condenser. Vermont Yankee spokesman said the condenser has been upgraded over time and the tubes were “re-sleeved” several years ago.
The cause of the “reduced performance” of the condenser isn’t clear at this point. Last week the back pressure level went up to 4.5 pounds per square inch. The maximum level for the plant is 5 psi, according to Sarah Hofmann, deputy commissioner of the Department of Public Service. At 7 psi, the plant is designed to SCRAM.
The state says Yankee technicians made a mistake and left a metal plate inside the component as they were trying to troubleshoot the issue last week. The plate was a piece of metal large enough for workers to stand on. Neil Sheehan is a spokesman for the Nuclear Regulatory Commission said the agency is aware of the incident, adding, “ It’s an issue that’s affected not only Vermont Yankee but numerous other plants over the years where there’s foreign material that’s left behind when a job is completed. We don’t think that’s acceptable and we certainly had that discussion with them and our inspectors will certainly be addressing that in an upcoming inspection report.”
Entergy is unlikely to replace the condenser until a decision is made in its favor to extend the plants current operating license in Vermont, which expires on March 21st, 2012, but the NRC issued a new operating license last year allowing the plant to continue operating until 2032.
In testimony, Fairewinds Associates noted that rather than invest $200,000,000 (in 2016 dollars) in a new condenser, Entergy may choose instead to shut down the plant as it would be difficult to recoup such a large investment during the final years of the
plants life. Especially if Entergy is losing more than it is profiting for extended periods, which may then cause the licensee to make drastic economical decisions in the face of mounting pressure to block the extension of the plants operating license. Entergy has admitted Vermont Yankee is a minimal profit producer and additional costs may prove too expensive, especially with the added costs of post-Fukushima upgrades, and conditions imposed after the NRC issued its 20-year extended license.
The NRC recently released an annual report on Yankee that cited a number of what it called non-safety issues at the plant. Since Louisiana-based Entergy Corporation purchased Vermont Yankee from state utility companies in 2002, the plant has had a string of physical plant problems including a water tower collapse in 2007 and a transformer fire. In January 2010, the company revealed that underground pipes at the plant were leaking tritium into soil on the compound, which is located on the banks of the Connecticut River.
The recent incident prompted the Shumlin Administration to ask federal regulators about a recent series of human errors at the plant. Public Service Commissioner Elizabeth Miller wrote Thursday to the head of the NRC’s Northeast region to say she’s concerned about what she called a pattern of human errors at the Vernon reactor during the past 15 months.
Commissioner Miller says the most recent incident of the metal plate left inside the condenser raised questions about whether Yankee was experiencing a pattern of human errors. “In looking at the reports I had a concern that there had been a number of incidents and felt it was appropriate to ask the NRC to explain why that pattern of incidents didn’t deserve further attention or further action by the NRC and so that’s why we sent the letter.”
Miller lists five errors, ranging from failure to remove a plastic cover from a pump before it was installed to inaccurately measuring the dose rate from a shipment of radioactive waste. Miller’s letter to the NRC cites other mistakes, including a case last fall when Yankee technicians misread a work order and shut down a breaker which resulted in a brief loss of the shutdown cooling system, and another case in December when workers mistakenly tripped the wrong diesel back-up generator.
The NRC labeled all five incidents as minor, but Miller is questioning why they aren’t being considered as part of a pattern. Yankee spokesman Larry Smith said he could not comment on Miller’s letter. The NRC said it would review it. In addition to conducting two reviews in 2012 — at mid-cycle and end-of-cycle — the NRC will also review Yankee’s implementation of an industry initiative meant to control degradation of underground piping.
In 2009, the Vermont Senate voted to deny permission for Entergy to obtain a certificate of public good from the Public Service Board for relicensure of the plant. In February 2010, the Vermont Senate voted 26 to 4 against re-licensing of the Vermont Yankee Nuclear Plant after 2012, citing radioactive tritium leaks, misstatements in testimony by plant officials, and other documented on-site events. Entergy sued the state over several statutes, including one that gives Vermont jurisdiction over the continued operation of the plant past the 40-year deadline and a say in the long-term storage of nuclear waste on site.
A state law that prevents the plant from storing spent fuel at Vermont Yankee after that date without approval from the Public Service Board. Last week the board questioned whether it had the ability to let Vermont Yankee keep producing spent fuel and pushed Entergy attorneys on why they hadn’t addressed the impending issue earlier. Federal district court Judge J. Garvan Murtha ruled the Atomic Energy Act pre-empted the two state laws, but his decision left the Public Service Board’s discretion intact. The Public Service Board held a status conference March 9 at which they would not guarantee that the plant would keep operating, and briefs are due Friday.
When the board reopened the proceeding and asked whether the plant could continue to operate, Entergy fired off an immediate request to the court asking it to let the plant operate after March 21, implying it might continue operating, even if the board says it should not.
“[O]n March 9, 2012, the PSB made clear that it does not necessarily agree with the AG’s and the DPS’s view. In the event that the PSB ultimately disagrees, Plaintiffs will be forced either to cease operating or, if they defy the PSB by continuing to operate, to face the prospect of a diminished credit rating, a loss of crucial employees, and a demerit in the PSB’s consideration of Plaintiffs’ petition for a new CPG.”
Entergy has a track record of deferring maintenance, exampled by the 2007 collapse of the cooling towers, was found to be caused by corrosion in steel bolts and rotting of lumber. Some still think that a corporation that buys an aged nuclear plant fully aware of the pending decommissioning agreement with the state, ought to be bound to decommission it. However, right in the middle of the Fukushima disaster the NRC grants another 20 years to an old, trouble ridden plant, doesn’t that just beat all…