Crews at the Dresden Generating Station in Morris, IL, have been working to secure a leak of tritiated water detected over the weekend. Tritiated water is a radioactive form of water where the usual hydrogen atoms end up replaced with tritium.
Sampling on Saturday turned up elevated tritium levels in a single test well near a contaminated water storage tank, according to Exelon and a report filed with the Nuclear Regulatory Commission (NRC).
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The leak from the tank ended up confined to plant grounds. Exelon notified the state of Illinois the sampling showed tritium at 1.3 million picocuries per liter. That exceeds the NRC’s limit for release into the environment, which is 1 million pCi/L.
Exelon said Monday that crews have worked around the clock to excavate the area around the tank, identify the leak and repair it.
Testing also found low levels of tritium in a waste water treatment facility.
“As part of the Station’s extensive environmental monitoring and sampling program, sample results from an onsite sampling well near the 2/3 contaminated water storage tank indicate elevated levels of tritium. This is an on-site leak, requiring the notification of the State of Illinois. Based on sampling data obtained, the tritium is currently confined to Exelon property,” said the company in its filing with the NRC.
Sample points are part of the station’s extensive environmental monitoring program designed to detect unusual levels of tritium in the environment and are tested on a monthly basis.
“Our monitoring program functioned as designed, alerting us to the presence of tritium early so we can address the issue quickly and effectively,” said Dresden Site Vice President Shane Marik. “We care about the environment and will be doing everything humanly possible to quickly find the leak source and fix it.”
The plant southwest of Chicago operates two General Electric boiling water reactors completed in 1970 and 1971 that each generate about 870 megawatts.