Yankee leak triggers visit from top

Article published Jan 12, 2010

By Susan Smallheer Staff Writer
BRATTLEBORO - A top-level official from the Nuclear Regulatory Commission was in Vernon Monday, sitting in on meetings with Entergy Nuclear on how to handle the newly discovered radioactive leak at Vermont Yankee.

Donald Jackson, the NRC section chief, was attending the Entergy meetings, according to Neil Sheehan, commission spokesman.

Sheehan said Jackson would be in Vernon today also, as Entergy officials and its special team plot a strategy on what to do about the leak that first showed up on tests taken in November in monitoring wells. Subsequent tests last week showed the tritium levels had risen sharply, from 700 parts to 17,000 parts per liter.

Uldis Vanags, the state's nuclear engineer, said the first priority was locating the source of the tritium, a radioactive isotope that is a byproduct of nuclear power production. He said the state was waiting for Entergy to locate the source and then would be involved in the cleanup process.

Arnie Gundersen, a nuclear engineer who is a consultant to the Vermont Legislature and was a member of the state's Vermont Yankee Oversight Panel, said that in 1976 the plant's condensate storage tank leaked significant amounts of tritium-contaminated water into the Connecticut River.

Gundersen cited a 2006 survey that Entergy Nuclear filled out for the NRC as the source of his information about the condensate tank, which holds hundreds of thousands of gallons of water.

According to Entergy's own letter to the NRC, "a significant spill of tritiated water occurred at Vermont Yankee in 1976." The spill released 507 microcuries of beta-gamma activity, the report stated, as well as 1.6 curies of tritium.

Last week's discovery measured the tritium in picocuries, which is a very small fraction - one trillionth - of a curie. A microcurie is one millionth of a curie.

Vanags said he was aware there had been a significant spill in 1976, but at this time did not have the details.

According to Sheehan, the condensate storage tank sits on a concrete pad and is surrounded by a concrete berm. He said any leak would be visible.

Williams said the condensate tank was being investigated as the potential source of the new tritium reading. He said the tank was south of the reactor building.

"In 1976, 34 years ago, there was a spill of water from the condensate storage tank containing tritium. However, that spilled water drained to the river and it was not a groundwater contamination issue," Williams wrote in a later e-mail. "The investigation that we have under way is a thorough, comprehensive, methodical process with the benefit of industry experience) and we are considering all sources of tritiated water at the plant including the condensate storage tank and its associated connections."

He said the Entergy task force would decide when and where to drill additional monitoring wells, which would be used to help identify the source of the tritium.

In the case of the 1976 spill, the water "flowed through the plant storm drain system to the Connecticut River" but no water entered the groundwater table at the plant site.

Monitoring groundwater at nuclear power plants became a priority for the NRC in 2006 when contamination surfaced at several plants, including Oyster Creek in New Jersey and Indian Point, north of New York City. Tritium problems were identified a couple of weeks ago at another Entergy reactor, the FitzPatrick reactors on Lake Ontario.

Sheehan said the condensate storage tanks hold hundreds of thousands of gallons of water that contain radioactivity. The water has circulated through the reactor and has high levels of tritium, he said.

Sheehan said that after Jackson leaves Vermont Yankee, the NRC's two resident inspectors will be reviewing Entergy's efforts. "We will be developing plans for additional inspections," he said. Williams said he did not know how much water had been spilled in the 1976 incident.

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