MONTPELIER, Vt. (AP) - Owners of the Vermont Yankee nuclear power plant said Thursday the state may be overestimating the amount of radioactive tritium found in water samples taken from the Connecticut River.
The Vermont Health Department announced test results Wednesday confirming for the first time that tritium leaking from the Vernon reactor had reached the river. The department said two samples taken from the river's shoreline last month showed concentrations just above what is known as the minimum detectable amount.
But New Orleans-based Entergy Corp. issued a statement, saying its testing of the same July 18 and July 25 samples showed levels of tritium below the minimum detectable amount.
"Results from our laboratory testing of those same samples ... show levels that are below that same extreme lower limit," Vermont Yankee spokesman Larry Smith said.
Smith said he could not explain how the company was able to detect tritium at levels below the "minimum detectible." He said Entergy wants an independent third party to analyze both sets of test results to resolve the discrepancy.
Tritium is an isotope of hydrogen that has been linked to cancer when ingested in large amounts. It has leaked from dozens of nuclear plants around the country, including Vermont Yankee and the Pilgrim nuclear plant in Plymouth, Mass. Both plants are owned by Entergy.
Also Thursday, Entergy came under continued criticism from Gov. Peter Shumlin, who said at his weekly news conference state test results confirm his belief that the plant should have been more aggressive about cleaning up a tritium spill first reported in January of 2010.
Shumlin said no one should be surprised that tritium was turning up in the river. State health officials have been saying since February of 2010 it should be assumed the substance was reaching the waterway, but was being diluted by river water to levels that could not be detected.
"I'm surprised that anyone is surprised," the governor said.
Sandra Levine, a senior attorney with the Conservation Law Foundation's Montpelier office, also criticized the plant.
"It certainly shows that their remediation and cleanup have been inadequate and that the testing has been inadequate," Levine said in an interview. "It shows the abject failure of Entergy to responsibly manage the plant first to avoid problems and secondly to clean them up."
A New Hampshire state official said the state would conduct additional testing of the Connecticut River in the wake of Wednesday's announcement. The plant sits across the river from New Hampshire.
Joan Ascheim, bureau chief for New Hampshire's public health agency, said the tritium findings didn't necessarily present a health risk to the public but were still a concern. She said New Hampshire has been testing for months but hasn't gotten any results above the minimum detectable levels.
New Hampshire collects and analyzes environmental samples each year in 10-mile emergency zones of Vermont Yankee and Seabrook Station nuclear power plants, Ascheim said.
Both Massachusetts and New Hampshire have towns within Vermont Yankee's 10-mile zone.
Lisa Capone, assistant secretary of the Massachusetts Executive Office of Energy and Environmental Affairs, said the administration of Gov. Deval Patrick wants the tritium leaks resolved before the federal Nuclear Regulatory Commission issues a 20-year license extension Entergy is seeking for Pilgrim.
The agency already issued an extension for Vermont Yankee, but Vermont is trying to block the plant from operating after next March.
"In light of reports that tritium has been detected in the Connecticut River in Vermont, we continue to believe strongly that the NRC should halt further consideration of relicensing at Pilgrim until conclusive test results are in and leak issues relating to Entergy's plants are resolved," Capone said in a statement.