Steam containing radioactive tritium escaped from a valve at an Exelon Corp. plant even as company officials met with local residents to discuss efforts to clean up earlier leaks.
About 500 gallons of water pooled on the grounds of the Braidwood Generating Station as the steam condensed Thursday, and some of it flowed into a ditch that lies between the plant and the village of Godley, company spokesman Craig Nesbit told the Chicago Tribune for a story on its Web site.
Tests showed no detectable levels of tritium in the water in the ditch, although levels measured in the water pooled on plant grounds were more than twice federal drinking and groundwater limits, Nesbit said. He said more precise testing would be conducted.
The company created a dirt berm around the ditch and placed a bladder in the ditch to create a dam, Nesbit said.
Tritium is a radioactive form of hydrogen commonly found in ground water but is more concentrated in water used in nuclear reactors. According to the U.S. Environmental Protection Agency, exposure to tritium increases the risk of developing cancer.
The Braidwood plant, located about 60 miles southwest of Chicago, has sent millions of gallons of tritium-tainted water into the ground in several leaks dating back to 1996. When Thursday's release happened, Exelon officials were meeting with residents to discuss plans to clean up earlier leaks.