Elevated radioactivity levels found in North Anna well

Dominion Virginia Power has found elevated levels of a weak form of radioactivity in a sampling well at its North Anna nuclear power station.

The radiation poses no hazard to the public, the Nuclear Regulatory Commission said.

On Friday, the Richmond-based utility was notified by its laboratory contractor that water taken from an on-site groundwater sampling point contained an unusually high level of tritium — more than twice the EPA's standard for drinking water.

"At this point, I don't think there's any concern on the NRC's part that it would affect (nearby Lake Anna) or drinking water supplies," said Roger Hannah, a spokesman for the federal regulatory agency's Atlanta office.

Dominion Virginia Power is not sure where the radioactivity is leaking from, but the two reactors at the Louisa County plant are not the source, company spokesman Rick Zuercher said.

The company said it has been working to find and fix potential sources of the escaping tritium and that the contaminated water is not leaking off-site.

"There is no evidence that the increased concentration of tritium we sampled was related to the earthquake" on Aug. 23, which shut down the plant for nearly three months, the company told the NRC on Tuesday. "Monitoring of the sample points both inside and outside the protected area and a post-seismic hydrogeological evaluation show this to be the case."

However, one anti-nuclear group was skeptical of Dominion Virginia Power's and the NRC's efforts to solve the leak issue.

"We remain concerned about the inaccessible piping systems that carry radioactive water," said Paul Gunter with Beyond Nuclear, which is based in Maryland. "The industry and the NRC are basically groping in the dark to find these leaks."

Tritium is a naturally occurring radioactive form of hydrogen, but it also is produced as a byproduct of the nuclear reactions in power plants like North Anna.

Tritium emits a weak form of radiation, the NRC said. Because it is produced by cosmic rays colliding with air in the atmosphere, the federal agency said, tritium is found in very small or trace amounts in groundwater throughout the world.

Exposure to radiation can have adverse health effects. For instance, radiation doses can increase the chance of getting cancer and causing genetic abnormalities in future generations.

"Last Friday, we received confirmation from an outside contractor that tritium at a sample point exceeded the voluntary reporting level established by the nuclear industry in 2006," the company told the NRC on Tuesday.

"No detectible tritium was found in any of the other nine sample points within the protected area," Dominion Virginia Power said, "and there are no sources of drinking water in this area."

The company is collecting the contaminated water in subsurface drains and processing it on the plant site, Zuercher said.

The industry's voluntary threshold for reporting such contamination — which Dominion Virginia Power adheres to — is 20,000 picocuries per liter. The sample the company took showed a radiation concentration of 53,300 picocuries per liter.

Picocurie is a term that describes how much radiation and, therefore, how much tritium, is in the water. The EPA's maximum contaminant level for tritium in drinking water is 20,000 picocuries per liter.

In October 2010, Dominion Virginia Power reported a confirmed tritium sample of 16,500 picocuries per liter in another sampling point in the North Anna plant's protected area.

"We will continue to identify and repair any other potential sources," the company said.