BRATTLEBORO — Environmental groundwater and soil monitoring of the Vermont Yankee site has turned up 17 "areas of concern," but only five of those areas are so polluted they need additional cleanup, according to representatives from NorthStar Nuclear Decommissioning Co.
The contaminated areas stem mostly from historic fuel oil leaks, NorthStar said.
"Five need attention," said Corey Daniels, NorthStar's decommissioning manager told members of the Vermont Nuclear Decommissioning Citizen Advisory Panel last Thursday.
In addition, two diesel fuel spills also need minor cleanup, Daniels said.
Daniels said the 17 areas are mostly polluted from oil products — specifically diesel fuel or fuel oil — and are located near underground pipes carrying the oil, including near the 75,000 gallon underground diesel tank that provided fuel to Vermont Yankee's backup diesel generators.
He said there is a "legacy" spill near the site of the former Yankee cooling towers, which were demolished earlier this year.
He said that NorthStar had responded to concerns raised by state officials and had drilled six additional monitoring wells. NorthStar was already working with 32 existing wells.
NorthStar is working with Vermont state officials to locate and clean up any contamination as part of the overall decommissioning of the nuclear plant.
NorthStar is now updating its site investigation report, which was submitted in July.
The revised plan, including the requests from state environmental officials, addressed "data gaps" at seven areas of concern. It will be completed in the first quarter of 2020.
He said of the areas that will need to be remediated, the soil will be dug up and sent to a low-level radioactive waste facility in Texas..
Additionally, he said a detailed radioactive sweep of most of the 143 acres that make up the Vermont Yankee site has so far only turned up two minor spots of radioactivity — one site was a tool box and the other was "minor shine" from where radioactive materials were staged before they were shipped.
"Other than that, there have been no surprises," he said
He said NorthStar is using what he called "an ultra all terrain vehicle" that can measure the radiation on the site to the depth of several feet. He told the panel that the special vehicle, which can measure wherever it can be driven, has already made 1.3 million "discreet measurements."
Daniels said NorthStar is updating Yankee's site investigation report to include additional data. The contaminated soils in areas that can be accessed will be remediated.
In the meantime, NorthStar is continuing biweekly meetings with the Agency of Natural Resources, which is overseeing the non-radiological cleanup of the Vernon site.
Daniels said the state, with its heightened awareness of PFOA chemicals, has required that NorthStar test the areas, and Daniels said he is glad to report that no PFOAs were detected.
He also gave an update on the infiltration of groundwater into the turbine building. Back in 2015, when the problem was discovered, the infiltration amounted to about 6,000 gallons a day and forced Entergy Nuclear, the owner at the time, to store the radioactive water in portable swimming pools and tanks.
Thanks to efforts to divert groundwater away from the contaminated building, the infiltration has dropped to about 300 gallons a day. The lightly radioactive water is still being shipped to a facility in Idaho, Daniels said, about a tanker car's worth every two months.
"Technically, it's safe to make coffee with," he said, referring to the low level of radioactivity in the water.
He said the water being intercepted before it reaches the turbine building has tested clean of any radioactivity. NorthStar is still in the process of setting up more intercept wells.
Daniels said that since decommissioning began in January, NorthStar employees and contractors have logged 260,000 hours without a lost-time accident. And he said radiation exposure to those employees and contractors is well within NRC limits.
Contact Susan Smallheer at email@example.com or at 802 254-2311,ext. 154.