A Note from Rob Williams at Vermont Yankee
February 4, 2010
Vermont Yankee engineers working to identify the source of tritium in the plant’s groundwater are methodically installing new wells closer to several plant structures to further characterize the tritium concentration in the groundwater near equipment and buildings.
The continuing sampling of monitoring wells is helping the investigation team locate the source. The good news is that one newly installed well, located just to the east of the plant’s condensate water storage tank and some underground piping, appears to be closer to the source because its concentration is 774,825 picocuries per liter.
The well that was first identified with tritium is now at 36,261 picocuries per liter. However, a well about 75 feet to the south of that one that has been as high as 80,458 picocuries per liter, is now down to 69,392. Another recently installed well further south is at 1,940 picocuries per liter, up from a recent level of 1,800. Such variation is as expected with variations of groundwater flow.
As has been the routine during this investigation, this information is being used with hydrology and monitoring studies already underway. The data received is helping direct investigators toward the source. While this process continues, it is important to note that there has been no elevated tritium level found in any drinking water well samples or at any location not on plant property.
For more details on the tritium investigation, the Vermont Department of Health has a thorough status report on the investigation at this web link: http://healthvermont.gov/enviro/rad/yankee/tritium.aspx
Also helpful is the Nuclear Regulatory Commission web page on tritium monitoring: http://www.nrc.gov/reactors/operating/ops-experience/grndwtr-contam-tritium.html
- Rob Williams
Entergy Vermont Yankee
Rwill23@entergy.com
