Jeremy L. Dillon
RW Monitor
2/13/2015
Vermont state officials discovered Strontium-90 in samples of groundwater collected in August 2014 from monitoring wells within the boundaries of Vermont Yankee, the Vermont Department of Health announced this week. The discovery marks the second radioactive isotope detected in groundwater in the boundaries of Vermont Yankee following the discovery of a tritium leak in 2010. Vermont, though, said the highest level of Sr-90 concentration was 3.5 picocuries per liter, below the Environmental Protection Agency’s drinking water threshold. “This is the first time Sr-90 has been found in ground water at Vermont Yankee,” the Department of Health said in a release. “The water is not available for consumption, the levels detected are well below the EPA’s safe drinking water threshold, and there is no immediate risk to health.”
The Sr-90 discovery came as a result of the state’s routine environmental analysis. After sending 21 samples to the state’s contract laboratory, the laboratory reported to the Health Department that four of the seven samples had levels of Sr-90 above the lower limit of detection, the state said. Vermont, in consultation with the Nuclear Regulatory Commission, then confirmed the findings by sending samples to the Oak Ridge National Laboratory for independent analysis. Entergy, owner of the Vermont Yankee site, also conducted its own independent analysis, resulting in similar findings. “Upon learning of the DOH’s laboratory results, Entergy immediately conducted a detailed analysis by an independent certified lab utilizing techniques that comply with industry standards and suited for detecting all relevant radionuclides to the established minimum detectable levels,” Entergy spokesman Marty Cohen said. “These results were communicated to the State by letter dated January 30, 2015.”
Findings Indicate What Has Leaked From Vermont Yankee
While the Sr-90 detected will not affect public safety, it will give a better picture of what has leaked from Vermont Yankee, which should help the decommissioning process, the state said. “These new findings of Sr-90 in ground water monitoring wells are an important indicator of what has leaked from the structures, systems and components at Vermont Yankee Nuclear Power Station,” the Department of Health said in a release. “Although the specific source of the Sr-90 is unclear, it is likely that Sr-90 in ground water and soils at Entergy Vermont Yankee are the result of past leaks and fallout from air releases at the station during its years of operation. The Health Department will continue its radiological surveillance program around Vermont Yankee.”
Entergy, meanwhile, said the findings will be documented for future cleanup. “In accordance with NRC regulations, this issue will be included in Vermont Yankee’s decommissioning files for further resolution once physical decommissioning and site clean-up are undertaken,” Cohen said.
Entergy has submitted its Post-Shutdown Decommissioning Activities Report for Vermont Yankee, with minimal changes to the plan outlined in its site assessment report the company issued in 2014. The PSDAR estimated the cost of the cleanup at $1.24 billion, with costs associated with terminating the NRC operating license at $817 million, spent fuel management at $368 million, and site restoration at $57 million. Entergy also is seeking an additional $145 million credit line to help pay for initial spent fuel management costs. Because the reactor is shutting down prematurely, its decommissioning trust fund has not accrued enough interest to cover the costs. The SAFESTOR option enables the fund to grow enough to cover the costs, and Entergy has pledged to the state of Vermont it would not use the full 60 years allotted under the NRC regulation, rather it would begin when the fund had the necessary funds. Entergy anticipates beginning work in 2040, with spent fuel moved to dry cask storage by 2020.
