Satisfaction growing as tritium level is shrinking

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DIAMOND - City of Braidwood employee Dave Tutterow of Dwight believes Exelon Nuclear is taking the necessary steps in resolving the tritium issue. “I really don't think there's that much problem,” he said Thursday during the quarterly Community Inform-ation Night conducted at the Cinder Ridge Golf Club by Exelon Nuclear and Braidwood Gener-ating Station. “I thought they had it under control before, and they seem to be keeping up with keeping people informed. They're doing what they have to do to get it resolved.” Tritium is a naturally occurring isotope of hydrogen that emits a very low level of radiation, and is found in more-concentrated levels in water used in nuclear generating stations. Tutterow was among the visitors at the latest Community Information Night - an outgrowth of the series of tritium-laced water spills at Braidwood Station in Braceville, beginning in 1996. Other visitors included Joe Cosgrove, spokesman for the Godley Water District, which tentatively plans a Saturday, Oct. 25, groundbreaking on the village's new municipal water distribution system, to which Exelon contributed $11 million a year ago. “I'd have to say Exelon is being very receptive to community questions and concerns, as opposed to eight years ago, when we couldn't get answers,” he said, adding the community needs to progress from then to tomorrow. The spills released about six million gallons of tritiated water into the ground in and outside the Braidwood Station site. Exelon, however, did not make the incidents public until a decade later in December 1996. The Nuclear Regulatory Commission has gone on record stating public health and safety has not been jeopardized by the tritium releases. Braidwood spokesman Jim Gosnell noted the plume of tritiated groundwater, which previously extended about 50 to 100 feet on the east and north of the manmade lake into which the underground water is being drawn, has receded to the shoreline there. “On the western shore, part of the plume has shrunk 50 to 75 feet toward the pond,” he said. “Also, the higher concentration areas (of tritium) south of Smiley Road have all disappeared. These have migrated into the pond, mixed with the pond, and removed by our pump system down the blowdown line. “That's in a nutshell where we're at.” Exelon is actually ahead of schedule in removal of the plume, which basically lies about 10 feet below the surface. Indications are the pumping could be completed in two to three more years. Initial estimates called for about seven years of pumping in the effort, which began in June 2006. Now, only 2 1/2 years later, Exelon is about half through with the pumping program. Another plus is the recent September rains which, although the runoff flooded areas in and around Grundy and Will counties, benefited the program by helping flush the soil and draw the tritiated groundwater back to the pond faster. “The record rainfall really helped us out a lot,” Gosnell noted. Conversely, when the ground is dry, the plume's migration still continues, although at a reduced pace. The cleanup will become more slow towards the end of the program. This is because less and less tritium is being removed for the same amount of water in the system. The program is finished after all the wells in the area - sampled on a quarterly basis - show the tritium level in the groundwater at below 200 picocuries per liter in two consecutive samplings. “Or to the extent practical, and that would be agreed upon with the Illinois EPA,” said Gosnell. “In other words, if we're pumping and pumping, and we're down to 300 picocuries per liter in all areas, and from appearances it's not going to clean up much more than that, the IEPA may say, ‘It's good enough.'” Exelon's goal, however, is to get the tritium level below 200 picocuries in all areas. The federal maximum for tritium is 20,000 picocuries per liter, while the California maximum is more stringent, at 400 picocuries per liter. Gosnell said the plume maps of 2006 indicate concentrations of hundreds of thousands of picocuries per liter south of Smiley Road, but have since been cleaned up. There still may be some small pockets that approach 5,000 picocuries, he noted. Although Exelon is satisfied with the progress to date, the utility continues to look for ways to improve this, and is currently undertaking comprehensive sampling to recharacterize the plume. “How big it is, and how aggressively we need to continue pumping this pond,” Gosnell noted. “We want to be good neighbors, too, but we want to do the responsible environmental thing, so there's a balancing act there.”