MONTPELIER, Vt. — State officials said Wednesday more radioactive tritium had been found at the Vermont Yankee nuclear plant — at levels more than 90 times higher than found in a test well nearly two weeks ago.
William Irwin, the state’s radiological health chief, said readings of 1 million to 2 million picocuries per liter of the isotope were found in a concrete trench several hundred feet from the test well where tritium was first reported Jan. 7. A spokesman for the federal Nuclear Regulatory Commission put the number at “about 2 million.”
That previous high reading turned up a sample of 22,300 picocuries per liter of tritium at a test well Tuesday, officials at Vermont Yankee said. But they downgraded that reading to 19,500 on Wednesday.
The Environmental Protection Agency safety standard for tritium in drinking water is 20,000 picocuries per liter.
Also Wednesday, plant spokesman Robert Williams said the announcement a day earlier that radioactive tritium had turned up in a second testing well at Vermont Yankee was based on a “false positive” test on a water sample taken from the well.
State and Vermont Yankee officials said Wednesday they hoped the finding of much higher tritium concentration in the concrete trench might mean they had found the source of the contamination.
“The water and the tritium content found in the 40-foot long concrete pipe trench is an important finding in the investigation of the source of the tritium found in the monitoring well,” Williams said in an e-mail. Other officials said the trench had not been confirmed as the source, but that drilling more test wells could lead to that conclusion.
Williams said it did not appear from initial checking that pipes running through the trench were leaking the radioactive water. Another possibility was that water was leaking through the concrete walls of the enclosure, officials said.
Meanwhile, legislative leaders and the Douglas administration’s point person on utility regulation said the state Health Department should conduct its own tests for radioactive leaks at Vermont Yankee and not rely on the plant for information about testing around the Vernon reactor.
That call came a week after it was revealed that Vermont Yankee, owned by New Orleans-based Entergy Corp., had misled state officials by saying the plant did not have underground piping of the type that could carry radioactive substances like tritium.
“Since Vermonters have lost confidence in Entergy Louisiana’s credibility, the Speaker (of the House, Shap Smith) and I urge the Department of Health to immediately implement independent, verifiable testing,” said Sen. Peter Shumlin, Senate president pro tem and Democratic gubernatorial candidate whose Windham County district includes Vermont Yankee. “This independent testing is critical to ensure Vermonters that we are getting reliable information about this crisis.”
David O’Brien, commissioner of the Department of Public Service, agreed that independent testing was needed. “We want to be able to have public confidence in the information we’re getting from the site,” he said.
Williams said state officials, including the member of O’Brien’s staff responsible for following developments at Vermont Yankee, already had been at the plant in Vernon, adding that it wasn’t clear to him what additional state oversight was being sought.
“We certainly will accommodate them on whatever additional monitoring they wish to do. We have been reserving samples for them” in the event that might happen, Williams said.
NRC spokesman Neil Sheehan said the trench contained pipes connecting tanks used to process radioactive waste at Vermont Yankee. He said the waste would be classified as “low-level,” versus the high-level waste that includes spent nuclear fuel or components removed from a reactor core when a nuclear plant is dismantled.