Yankee component leaks again
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By Susan Smallheer STAFF REPORT - Published: June 9, 2009
BRATTLEBORO – The Vermont Yankee nuclear plant will have to reduce power in the near future to fix another set of leaks in its condenser, Entergy Nuclear announced late Monday.
It is the second time in about a year that the Vernon reactor has developed leaks in the condenser, which is not involved in the nuclear safety side of the plant, but is used to cool the steam that makes the electricity generated at the plant.
Replacing a condenser is not a cheap or simple solution: Nuclear experts put the cost at more than $100 million, and it would keep the plant shut down for several months.
Entergy Nuclear spokesman Robert Williams said plant technicians noticed a change in the water chemistry of the reactor cooling system about two weeks ago, specifically an elevation in chlorine.
He said that was a giveaway that river water from the Connecticut River was leaking into the reactor cooling system.
The plant has had condenser leaks before, including last year, and the plant operated for several months without fixing them. It was only when the plant shut down in the fall for its regular refueling and maintenance that Entergy was able to find the leaks and fix them.
Williams estimated it would be several weeks before a plan to fix the leaks is in place — until then, the plant would continue to operate at normal levels.
The Vermont Yankee Oversight Panel had predicted in its report to the 2009 Legislature that the condenser would continue to be a source of problems at the plant until it is replaced. The problems at the condenser affect the plant's reliability and operation most directly.
A new condenser costs at least $100 million, said Arnold Gunderson of Burlington, a nuclear engineer who was a member of the legislative study panel.
By postponing the replacement of the condenser, the money will come from its proposed new corporate owner, Enexus, which state regulators have questioned as to whether it would be under-capitalized from the first day of ownership. Additionally, new power contracts after 2012 would reflect the cost of the $100 million project.
If the $100 million condenser were replaced before 2012, when its current federal license expires as well as its power contracts, Entergy Nuclear would have to foot the bill, he said.
Williams, the Entergy spokesman, said the company had decided not to make the investment in a new condenser until it knew it had federal and state approval for another 20 years of operation.
Gunderson said the leaks, and the fact that Entergy has so far refused to replace the condenser, is a troubling sign that Mississippi-based Entergy Nuclear isn't making all the investment it needs to into the 37-year-old reactor.
Gunderson said it is unusual for a nuclear reactor the age of Vermont Yankee not to have replaced the condenser.
While the condenser isn't considered a safety component per se, if it continues to leak and the plant's demineralizers and other filters fail, problems can occur in seconds, he said.
"You don't want crud getting into the reactor," Gundersen said.
Diane Screnci, a spokeswoman for the Nuclear Regulatory Commission, said it was not unusual for industrial plants – not just nuclear reactors – which rely on cooling water, to develop such leaks.
"This does not have safety significance," she said.
Entergy Nuclear has to operate Vermont Yankee's cooling water system with extremely pure water, she said.
Gunderson said Entergy's announcement specifically mentioned chlorine, which is naturally occurring in river water such as the Connecticut. But, he said, chlorine, at high temperatures such as in a reactor, is extremely corrosive to stainless steel.
"At 500 degrees, it just eats up steel," he said.
susan.smallheer@rutlandherald.com
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