February 26, 2010 – Morning Update
AOG Excavation Reveals Crack in Pipe Tunnel
At about 5:00 a.m. on Feb. 26, Vermont Yankee unearthed the concrete AOG pipe tunnel that carries the 2-inch drain line (labeled OGE-100-G1 Drain Line on the AOG Building schematic) at the point where the drain line connects to the AOG pipe tunnel. This revealed a substantial crack in the concrete and the PVC pipe that surrounds and carries the drain line into the tunnel. (This is depicted on the schematic as blue water drops). The crack runs from the outside of the concrete duct into the pipe tunnel.
This finding is good visual evidence of a possible pathway from the AOG pipe tunnel into the earth and groundwater.
Soil samples collected by a “core bore” taken from varying depths below the AOG pipe tunnel are being analyzed now by Vermont Yankee, with the expectation that analysis will show contamination with radioactive materials. Preliminary word from Vermont Yankee is that other radioactive materials have been detected in the soil, including isotopes of manganese, zinc and cesium. A split sample will be delivered to the Vermont Department of Health Laboratory for independent analysis.
Results may substantiate this crack as at least one pathway of contaminated water from the plant structures and systems into the groundwater.
Health Department staff are on site to monitor the continuing work. The Vermont Department of Health has requested that all findings and actions taken be documented by video and other means.
Although this is a significant finding that is consistent with previous findings (nuclear steam, standing water in the tunnel, and a clogged floor drain) more definitive evidence is still needed. “Leak testing” with pure demineralized water is scheduled for this weekend, Feb. 27 and Feb. 28, to help identify the actual mechanism and pathway more definitively.
This may not be the only pathway, and the investigation continues.
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Investigation Web site: http://healthvermont.gov/enviro/rad/yankee/tritium.aspx
Link to AOG Building schematic: http://healthvermont.gov/enviro/rad/yankee/documents/VY_tritium_map_AOG-Bldg_3Dgraphic.pdf
