ST. LOUIS — St. Louis-based AmerenUE said it is investigating newly discovered leaks of radioactive tritium from a pipeline at its Callaway nuclear power plant in Fulton, following half a dozen leaks from pipe breaks dating to 1987.

The pipeline runs cooling water and other waste from the plant near Fulton to the Missouri River. So far, no tritium or other radionuclides have been detected in two rounds of testing on private wells that supply drinking water to 20 neighboring properties.

"We don't want to see pipes break," said Floyd Gilzow, deputy director for policy at the state Department of Natural Resources.

"We don't want to see these kinds of unplanned releases and I don't think Ameren wants to see them either. Do they concern us? Of course they concern us. But the reality is we live in an imperfect world and occasionally things that are mechanical don't work the way they're supposed to."

Ameren, the plant's operator, said none of the leaks has threatened public health. The most recent leaks were discovered this summer, the St. Louis Post-Dispatch reported Sunday.

Tritium is a byproduct of power generation at nuclear plants like Callaway. It is considered one of the least-hazardous radionuclides, or atoms that emit radiation.

In one major pipeline break, in October 1995, two miles north of the Missouri River, water flowing from the broken pipe eroded a channel up to 12 feet wide and 12 feet deep to Logan Creek.

Plant estimates were that the leak began late that summer as a result of periodic flooding that apparently shifted and stressed the pipe.

Ameren is permitted to discharge water containing diluted levels of tritium into the Missouri River, where it mixes with river water and is further diluted.

"While there is no indication that tritium contamination from the Callaway Plant poses a health concern to plant employees or the public, AmerenUE does take the tritium issue seriously," company spokeswoman Susan Gallagher said. "We are working with the rest of the nuclear energy industry to develop additional tritium monitoring and control measures."

Low-level contamination was found in about half the soil samples taken this year from the manholes. One soil sample was slightly above the federal safety limit for tritium in drinking water.

Other documented leaks occurred in 1987, '88, '89, '98 and 2005.

David Lochbaum, director of the Nuclear Safety Project for the Union of Concerned Scientists, said the industry was required to report "significant" spills, and has now pledged to promptly report leaks in excess of 100 gallons to regulators and the public.

Ameren routinely monitors groundwater in nearby Portland, and the latest annual reports filed by the utility show no detectable levels of radioactivity.

Anti-nuclear activist Kay Drey, of suburban St. Louis, said she had always feared the pipes might corrode. Because some past leaks had reached creeks in the area, Drey said the public should be informed.

Ameren reports to the Nuclear Regulatory Commission, but Drey said that's not enough.

"My interest is reporting to the Missouri Department of Conservation and the public, who might hunt and fish there, and the farmers who may use the water and land for irrigation," she said.

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