May 18 - Knight Ridder/Tribune Business News - David Sneed The Tribune, San Luis Obispo, Calif.

Faced with growing concerns over radiological contamination of groundwater, the nuclear industry has adopted new guidelines for monitoring tritium leaks.

All nuclear power plants, including Diablo Canyon, will implement by July 31 the new guidelines that call for quick disclosure of any leak. In recent years, five nuclear plants have reported releasing tritium-tainted water.

Tritium is a liquid byproduct of nuclear reaction that emits low levels of radiation. It travels readily in water, making it particularly dangerous to groundwater, said Mark Somerville, a health physicist at Diablo Canyon.

Like all nuclear power plants, Diablo Canyon releases small amounts of tritium in the form of gas and water runoff, but it has not had the kinds of leaks that have caused problems at other plants. All of the tritium levels detected at Diablo Canyon are far below the limits set by federal regulators.

Diablo Canyon has several characteristics that make it less likely to have tritium contamination problems, Somerville said.

Most importantly, the plant sits atop a coastal bluff and does not have underground drinking water aquifers that could become contaminated in the event of a tritium spill. The plant gets all of its fresh water from desalination and Diablo Creek.

Also, the Diablo Canyon plant is contained in a relatively small area. Some other plants pipe water for miles, increasing the likelihood of a leak.

Tritium releases are often traced back to equipment degradation. At the Indian Point plant in New York, tritium leaked through a crack in the plant's spent fuel pools. The most recent release occurred in March at the large Palo Verde nuclear plant in Arizona, which supplies some of Southern California's electricity. Leaking underground pipes are suspected as the source.

Tritium leaks are the latest in a string of equipment problems nuclear plants are experiencing as they age. Operators at Diablo Canyon plan to replace the plant's steam generators and reactor tops because both components have deteriorated faster than anticipated.

Under the new industry guidelines, nuclear plants must disclose tritium leaks that stay confined to the power plant site just as they would leaks that pollute public water sources. Plants also must report such leaks to local health authorities within a few days of the release.

The new industry guidelines exceed rules established by the Nuclear Regulatory Commission and are intended to increase public confidence in nuclear power, said Ralph Andersen, chief health physicist with the Nuclear Energy Institute, the nuclear industry's trade association.

"Even in the instances where inadvertent radiological releases in groundwater occur at levels that do not require formal reporting, we should inform local and state leaders and the public as a matter of openness and transparency," Andersen said.

Reach David Sneed at 781-7930.