Test suggests radioactive leak at Yankee
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By Susan Smallheer Staff Writer - Published: January 8, 2010
BRATTLEBORO — Entergy Nuclear announced late Thursday one of its monitoring wells on the banks of the Connecticut River had detected radioactive tritium contamination, the first time such contamination has shown up at the plant.
Tests show tritium levels have risen sharply since it was first discovered six weeks ago.
The well, located between the reactor building and the river, first showed contamination of radioactive tritium at 700 parts per liter in mid-November, but by Wednesday, the contamination had jumped to 17,000 parts per liter.
Another test Thursday showed levels of 14,500 parts per liter, according to William Irwin, radiological health chief for the Department of Health. Entergy Nuclear spokesman Robert Williams said the tritium was below reportable federal levels, and he and Irwin both said tritium at these levels did not pose a health risk.
"The public shouldn't be concerned about any kind of health consequences," Irwin said, "because the amounts that have been measured are very, very low." Williams said the 17,000 parts per liter level was about half the reportable level established by the Nuclear Regulatory Commission, which is 30,000 parts per liter.
Irwin said the contamination was on the Vermont Yankee site, and other monitoring wells outside the plant had not revealed contamination. Those community sites include Vernon Elementary School, which is located across the road from the reactor, as well as a local farm.
But Irwin noted the first test that showed the tritium was in November, and that by early January, the amount had increased, which he said he didn't have a good explanation for.
He said the pollution could increase, decrease or even disappear.
Williams said the contaminated well was about 30 feet from the Connecticut River, which showed no signs of contamination.
Entergy started the monitoring wells in 2007 and the state followed with its own monitoring in 2008, Irwin said.
The Nuclear Regulatory Commission had ordered the testing after tritium contamination showed up at several nuclear power plants in different parts of the country, including the Entergy Nuclear-owned Indian Point reactors in New York state.
Arnold Gundersen, a nuclear engineer from South Burlington who served on the special Oversight Panel that examined Vermont Yankee's reliability last year, said there likely was a plume of contamination under the reactor, and that concentrations of the tritium were likely higher in locations other than the well.
Gundersen noted that Entergy officials told his committee there was no underground tanks of piping that would have contained radioactivity, calling into question the accuracy of their reports.
"The Oversight Panel specifically asked about underground pipes and tanks, but we were stonewalled by Entergy. Tritium is a sign of a leaking pipe or tank. Entergy told the panel that they had no buried tanks or pipes containing radioactivity. This is an indication that a radioactive plume is moving under the VY site," Gundersen wrote in an e-mail.
Gundersen said the committee was very concerned about underground radioactive contamination at the site.
"The reason to be concerned where it's coming from and I'm sure that we, at the Department of Health, and throughout the state, are very concerned about," Irwin said.
He said the priority was to identify the source of the pollution, stop it and mitigate the contamination.
"This is the first day of the discovery, so it's really difficult to know," he said. "Something is the source of radioactive contamination."
Irwin said tritium can be naturally occurring, but in levels far below the 700 parts per liter that first showed up on Nov. 17. Tritium is also used in illuminated safety exit signs, he said.
Williams said Entergy Nuclear had already established a 10-member team to investigate the source of the tritium.
Irwin said the initial testing was done by Teledyne Laboratories in Knoxville, Tenn., but that Monday and Tuesday's samples and tests were done onsite by Entergy.
He said he expected the well would be tested repeatedly in the coming week.
"Those of us who were born and raised in Windham County, always hope for the best. We all hope that it's a minor problem," Sen. Peter Shumlin, the Windham Democrat who is president pro tem of the Vermont Senate.
The news about the tritium eclipsed earlier problems in the day at Yankee, when an emergency oil level warning sounded, indicating low oil levels in one of two recirculation pumps at the reactor. The pumps circulate the water that controls the power production levels in the reactor.
The reactor was in the process of returning to full power when the warning came on, Williams said.
But by the afternoon, tests showed that the pump was working properly despite the warning light, said Uldis Vanags, the state nuclear engineer. Entergy resumed bringing the reactor back to full power, closely monitoring the pump, he said.
Entergy had reduced power at Yankee to about 60 percent Wednesday due to a broken 500-pound porcelain insulator in the VELCO switchyard, immediately adjacent to the plant.
VELCO spokesman Kerrick Johnson said it took about 11 hours to replace the insulator, one of about 100 in the yard.
susan.smallheer@rutlandherald.com
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