Vermont Yankee communications manager Larry Smith issued a statement today indicating that monitoring wells at the nuclear power plant in Vernon show that no new radioactive leaks are occurring at the plant. The statement also indicates that no drinking water wells in the area have been contaminated or are in danger of such from the tritium leaks.
As part of its campaign to better understand site hydrology, the statement says, and help monitor groundwater, Vermont Yankee placed nine additional wells into service over the last two months. These wells were put in place to improve Vermont Yankee’s ability to monitor the groundwater on site and their installation is part of the site’s industry-leading groundwater monitoring plan. Seven of these additional wells are located outside of the current plume area and show no indication of tritium. Two of the additional wells are located inside the plume area. These two wells show concentrations of tritium that are consistent with the current understanding of Vermont Yankee site hydrology.
There is no risk to the health and safety of the public or to Vermont Yankee workers. Recent overburden well measurements at GZ-12D and GZ-22D confirm west to east groundwater flow in both the shallow and deep overburden regions. In addition, an upward flow direction is observed from the shallow bedrock to the overburden. (That is to say that the bedrock water pressure is elevated. Therefore, the bedrock aquifer is protected as well as public wells to the west.)
This is NOT an indication of additional leakage to the environment. The overburden wells were intentionally installed within the area affected by prior tritium leakage to better understand site hydrology and help monitor groundwater.
Nearby bedrock drinking water wells are NOT at risk of contamination. These bedrock aquifer wells are outside the path of the tritium plume and thus are not threatened by the plume.
New well GZ-12D has a tritium concentration of 65,000pci/L
This well is located inside the known existing tritium plume at a depth of 60 feet, just North of the Containment Access Building.
New well GZ-22D has a tritium concentration of 500,000pci/L
This well is located inside the known existing tritium plume at a depth of 60 feet and is adjacent to the former Construction Office Building Well.
The absence of tritium from the samples in GZ-23 ‘ GZ-27 indicate that there are no additional leaks at the site. These 2 Sentinel wells were installed immediately adjacent to structures, systems and components containing radionuclides. These wells will be monitored monthly as part of the site’s Groundwater Monitoring Program.
Evidence of tritium in GZ-12D and GZ-22D further helps us understand our site hydrology. Water containing tritium is present at the 60 foot level, just above the bedrock layer, but the upward flow of water from the underlying aquifer prevents this water from going deeper. Like all groundwater on the Vermont Yankee site, it flows above the bedrock layer in an easterly direction.
Drinking water wells are NOT at risk of contamination. These bedrock aquifer wells are outside the path of the tritium plume.
Source: Vermont Yankee. 12.3.2010