BRATTLEBORO -- For a number of reasons, the Nuclear Regulatory Commission should force Entergy to put into cold shutdown its Vermont Yankee nuclear power plant in Vernon, stated the New England Coalition on Nuclear Pollution in a filing to the NRC submitted Tuesday.
Those reasons include the increasing concentrations of tritium in groundwater below the plant, Entergy's failure to know and understand Yankee's design, layout and construction, the inadequacy of Yankee's underground piping aging management plan and the NRC's failure to identify the situation until it became "grossly self revealing."
Therefore, wrote Ray Shadis, NEC's technical consultant, the NRC should force Yankee to go into cold shutdown and depressurize all systems in order to slow or stop the leak.
Early last month, Entergy notified the state and the NRC that water containing tritium, a radioactive material produced by a nuclear power plant, had been discovered in a monitoring well in between the plant and the Connecticut River.
Since then, tritium levels exceeding 2 million picocuries per liter have been discovered in other monitoring wells and in new wells drilled to determine the extent of the plume and to identify the source of the leak.
Once the plant has been shutdown, said Shadis, Entergy would then be permitted to pressurize one system at a time, possibly using fluorescent dye tracers, in order to isolate the source of the leak.
"Poking holes in the ground and sampling is okay for site characterization, but it is an unnecessarily long slow path to isolating and identifying a leak," stated Shadis, in a document summarizing NEC's petition submitted to the NRC. "We suspect that Entergy is simply buying time until the scheduled April refueling outage."
In its petition, NEC is asking that the NRC require that Yankee physically trace details of the plant's systems to determine that everything about the plant is documented appropriately, including all underground piping.
In hearings before the Vermont Public Service Board, Entergy representatives testified that they didn't believe radioactive materials were being carried by buried piping. When the tritium leak was discovered, the state learned that there was in fact buried piping carrying radionuclides.
The PSB has ordered Entergy to go back and review all documents submitted to it to determine if any other information was left out.
NEC is also asking the NRC to investigate why Entergy has been operating Yankee since 2002 without a working knowledge of all of the plant's systems and why the NRC's Reactor Oversight Process and License Renewal Amendment Review Process, "let this dereliction go unnoticed."
In addition, wrote Shadis, the NRC should investigate Yankee's "many maintenance and management failures, and the Reactor Oversight Process's failure to get ahead of them."
Finally, the NRC should order Entergy to submit both an aging analysis and an aging management plan for all piping carrying or with the potential to carry radionuclides, he wrote.
What this all adds up to is the need for an independent safety assessment similar to one conducted at Maine Yankee in 1996, wrote Shadis.
It could take several weeks for the NRC to respond to NEC's petition, said Shadis.
"It could be dragged out," said Shadis. "But it's the only option we have."
Even if the leak is found between now and then, he said, it would be foolish for Yankee to continue operation.
"You're just waiting for the next leak to spring unless you go over the entire pipe system," said Shadis.
The NRC has no comment on NEC's petition, said Neil Sheehan, spokesman for the NRC.
"We have a process for handling such petitions and we will follow it," said Sheehan.
He did say that other plants in similar situations have not been shut down.
Bob Audette can be reached at firstname.lastname@example.org, or at 802-254-2311, ext. 273.