More cracks found in VY steam dryer
In its press release Yankee stated the steam dryer had been inspected and it "remains in very good condition."
No mention was made of the cracks, said Rob Williams, spokesman for Yankee, because they were not new and had been discovered using enhanced inspection techniques. Inspections of the steam dryer during three refueling outages were required by Vermont's Public Service Board when it authorized the plant to increase power production by 20 percent in 2004.
"In our best engineering judgment, these cracks have been there since the early days of plant operation," said Williams.
"Why should we trust them?" asked Ray Shadis, technical consultant to the New England Coalition on Nuclear Pollution, which raised issues with the Atomic Safety and Licensing Board about fatigue cracks in the dryer.
Shadis said Entergy, which owns and operates Vermont Yankee, has not been totally up-front about problems at the power plant, including a failure last May of a gantry crane used to move nuclear waste and the collapse of a cooling tower in August 2007.
"They would not have told us about the collapse except for the fact that the photos got out," said Shadis. Pictures of the cooling tower collapse were forwarded to NEC by an anonymous source several days after the failure.
Shadis said Entergy doesn't do themselves any favors by not being as forthright as possible with information about the plant.
"Just tell us the way it is."
A spokesman for the anti-nuclear Citizen Awareness Network also expressed his dismay.
"Frankly, there is no reason to trust them based on their previous behavior," said Bob Stannard. "We have been told time and time again that things are fine there. The state was assured the cooling towers were fine just a couple of days away from having it almost collapse again."
Earlier this year Entergy revealed changes to the cooling towers meant to prevent a collapse such as had occurred in 2007 had led to sagging in a distribution pipe's support system. Entergy voluntarily supplied the information to the media after the problem was discovered.
The cracks identified during the most recent refueling outage and were not of the type that were of concern to NEC, said Williams.
"All were determined to be due to intergranular stress corrosion cracking."
NEC was concerned with metal fatigue, said Shadis, which happens when metal is flexed. The steam dryer is a static device with no moving parts meant to extract water vapor from steam produced by the reactor before it is sent to the power turbine.
Intergranular stress corrosion cracks occur "due to the relief of metal stress first induced by the heat of the original weld process," said Williams.
None of the additional cracks nor any of the previously identified cracks have grown since the last inspection, he said, nor were they related to metal fatigue.
The additional cracks weren't included in the original press release, he said, because close to 5,000 tasks were performed during the outage -- including inspections and parts replacements -- making it nearly impossible to inform the public of everything that was done while the reactor was being refueled.
It's up to the licensee to inspect the plant and up to regulators to oversee the process, he said.
"The dryer is in good condition and that's why it passed the inspection," he said.
Entergy is required to submit a report to the Nuclear Regulatory Commission following all outages, wrote Neil Sheehan, NRC spokesman, in an e-mail to the Reformer.
"They will need to document for us the results of their steam dryer inspections, as they have in the past," wrote Sheehan. "(But) Entergy does not need to file a report with us on every task undertaken during the outage."
Sheehan wrote that the NRC supplements its regular inspection program during outages because they are periods of high activity.
"That includes bringing in specialists coming in to evaluate discrete outage activities, such as the replacement of large components."
Whether Entergy is required to submit a report to Vermont's Department of Public Service was not known Tuesday night. DPS did not return a phone call for comment on matter.
In addition to determining the steam dryer was in good condition, Entergy inspection teams checked the reactor vessel as well as its surrounding containment structure and both were found to be in good condition, according to Williams.
Upgrades to the plant during the outage included service water valves and piping, the safety-related cooling tower cell, installation of a new main feedwater pump motor and routine refurbishment of the main turbine valves.
"Our team carefully selected the tasks to be done, planned each task and brought the plan together in a very successful outage," stated Entergy Vermont Yankee Site Vice President Mike Colomb.
The next refueling outage is scheduled for the Spring of 2010, at which time another inspection of the steam dryer will be conducted.
Though it's too late to bring the new cracks to the attention of the Atomic Safety and Licensing Board, which is reviewing evidence on metal fatigue cracks in the steam dryer submitted by NEC, Shadis said the organization will present the information to the Vermont Public Service Board, which is reviewing whether the plant should receive a certificate of public good to continue to operate from 2012 to 2032.
"That's for certain," he said.
Bob Audette can be reached at email@example.com, or 802-254-2311, ext. 273.
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