A Note from Larry Smith at Vermont Yankee

March 5, 2010

Vermont Yankee engineers and technicians continue their investigation into the source of tritium in the plant's groundwater. The Vermont Department of Health and Nuclear Regulatory Commission personnel are at Vermont Yankee monitoring the investigation.

Concrete blocks at the junction of the Advanced Off Gas pipe tunnel and the OG-100 drain line connection have been removed allowing telescopic camera and Remote Operated Vehicle (ROV) inspection of the tunnel. Today's inspection has revealed a dime/quarter size hole at an elbow in a 1 to 1.5 inch diameter AOG drain line. Water and steam can be seen coming from this hole. The visual inspection results will be used in conjunction with plant drawings to identify which of several pipes running through this area is at fault. Engineering is currently reviewing plant diagrams to identify the pipe and its path way within the tunnel. Water coming from this pipe is flowing down the tunnel to the sump drain and is being collected and processed through plant systems as designed. Examination of the tunnel will continue today with completion of the ROV inspection expected tomorrow.

Ongoing engineering activities include pipe identification and locations where guided wave technology can be used to inspect piping; inspection options to confirm the integrity of the Condensate Storage Tank; and the installation of two new monitoring wells. One well is to be located between GZ-10 and GZ-7, very near the CST. Installation of the second well, to be located between the Containment access Building and the Construction Office Building will commence this weekend. Down hole geo-physics testing of five wells is complete; the final well will be completed next week. The purpose of this testing is to determine the structure of the bedrock and will help engineers and hydrology experts to better understand how groundwater flows beneath the site.

While this investigation continues, it is important to note that there has been no detectable tritium levels found in any samples taken from drinking water wells or the river.

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