FOR IMMEDIATE RELEASE
TMI Responds to Monitoring Well Sample
Londonderry Twp., PA- (July 25, 2012) Chemistry technicians at Three Mile Island Nuclear
Generating Station have found a slightly elevated level of tritium in one monitoring well on
the site near the plant structure. This level is contained onsite, poses no health or safety
risks, and is located in an area where groundwater is re-circulated back into the plant.
The monitoring well is one of 55 on the island that samples groundwater. All groundwater in
the area of the monitoring well is captured by industrial wells that pump the water back into
the plant where it is used for non-potable purposes throughout the facility.
The slightly elevated level was identified in a monitoring well sample and confirmed by an
independent laboratory. Subsequent samples show declining concentrations. Tritiated water
at Three Mile Island is stored in tanks and carried by pipes. A team of technical and
environmental experts is working to track down the source.
“TMI’s groundwater monitoring program is very comprehensive and it worked exactly as
intended,” said Rick Libra, TMI Site Vice President. “We identified this one sample quickly
and we’re working hard to find the source and keep our stakeholders informed.”
Three Mile Island has a comprehensive radiological monitoring program that includes 55
wells and five additional sampling stations. No unusual levels of tritium have been found in
the other wells or stations. Local and state officials and the NRC have been notified.
Tritium occurs naturally in the environment, can be found at very low levels in nearly all
water sources and is among the weakest of all radionuclides. It is produced in greater
concentrations in commercial nuclear reactors and is monitored carefully under industrywide
programs. Tritium eventually breaks down into helium, the same gas used to fill
balloons.
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