VERNON — Entergy wants additional disposal options for Vermont Yankee's contaminated water, but federal regulators say they don't yet know enough about the liquid to approve that request.
Citing “uncertainty in the concentration of radionuclides in the water,” the Nuclear Regulatory Commission is holding off on allowing Entergy to ship Vermont Yankee water to a facility in Idaho.
“We're doing our due diligence to understand the radioactivity levels that would be involved with the shipments,” NRC spokesman Neil Sheehan said.
Vermont Yankee spokesman Marty Cohn said the NRC's request for more information is a procedural matter, and Entergy soon will file a detailed response with the agency.
There is “a whole team working on responding to and managing all of these issues,” Cohn said.
Process water and groundwater
There are two basic types of contaminated water at the Vermont Yankee, which stopped power production 15 months ago.
The majority is “process” water, liquid that had been used in plant systems. But administrators also have been dealing with greater-than-anticipated amounts of groundwater seeping into the lower level of the turbine building.
The latter issue made headlines when it was revealed that Entergy had temporarily stored some of the groundwater, which is contaminated with tritium, in commercial swimming pools. But those pools are now gone, and Entergy has begun shipping groundwater and process water to a disposal facility in Tennessee.
As of April 7, Cohn said 54,000 gallons of groundwater and 10,000 gallons of process water had left the plant via tanker trucks.
Much water remains, and Entergy wants NRC permission to also send liquid to a US Ecology hazardous-waste facility in Idaho. But the NRC has sent a letter asking for answers to several questions before ruling on the matter.
The agency wants to know more about potential radiation doses to workers who will be dealing with the liquid, including long-haul truck drivers and landfill employees.
The NRC also wants additional confirmation of the water's allegedly low levels of radioactivity. Officials wrote that “the basis for the assumed tritium concentration is unclear,” asking that Entergy provide more information about how the company arrived at its estimates.
Furthermore, the NRC's letter says that “the concentrations of the radionuclides in the water were based on data from a single sample.”
“Because the potential dose was estimated based only on one sample, the uncertainty in the concentrations, and therefore dose, may not have been adequately captured,” officials wrote.
Entergy, vendor say water is safe
Cohn said it's simply a matter of submitting more details to the NRC so that US Ecology will be recognized as a “licensed vendor” that can accept nuclear-plant water.
“They're asking for more information - clarification,” he said. “This is just part of the process.”
He added that both Energy and its current disposal company, EnergySolutions, have conducted multiple tests of Vermont Yankee water and repeatedly have confirmed low levels of tritium.
“Before [EnergySolutions] got started, they came and tested the water,” Cohn said. “They had to make sure their facility could handle it.”
Officials have said the water's radioactivity is so low that the trucks carrying it don't need to be specially marked. Also, EnergySolutions spokesman Mark Walker said at a recent meeting in Brattleboro that the Vermont Yankee water can be safely disposed of via absorption in a landfill.
“Entergy is doing their characterization of it,” Walker told the Vermont Nuclear Decommissioning Citizens Advisory Panel last month. “We do some testing of our own to ensure that the levels are as low as [Entergy says] they are. We're finding that is the case.”