San Onofre Discharge May Violate Rules : Environment: Board to decide if nuclear plant is in violation of federal permit in casting debris-filled water into the ocean.

Officially, the purpose of the state Regional Water Quality Control Board’s daylong public hearing Thursday was to hear testimony about whether San Onofre Nuclear Generating Station violates its federal pollutant discharge permit.

But, in hours of testimony from Southern California Edison, the plant’s operator, California Coastal Commission officials and several environmental groups, much of the debate seemed to focus narrowly on a single word: “significant.”

The word’s importance stems from the fact that, in order to comply with its federal permit, the nuclear plant must not significantly reduce the transmittance of natural light in ocean waters and must not significantly degrade the marine environment.

A 15-year, $46-million study commissioned by the California Coastal Commission has found that the nuclear plant’s cooling system sucks up and kills 21 to 57 tons of fish yearly, then discharges the debris-filled water into the ocean, reducing natural light on the ocean floor by as much as 16%.

The report, whose authors testified Thursday, concluded that these adverse effects appeared to constitute permit violations. But it is up to the regional board to make such an official finding and, if it sees fit, to issue a cease-and-desist order to the plant.

Dr. William W. Murdoch, who represented the California Coastal Commission on the three-member Marine Review Committee that authored the study, Thursday summed up its findings this way: “I have not told you about an ecological disaster. But we did find significant impacts.”

Meanwhile, Dr. Byron J. Mechalas, Edison’s representative on the committee, downplayed the study’s results to the board. While the study, which he endorsed, was an important scientific document, he said, it was not designed to measure permit compliance.

“There is always an impact when an industrial facility is built. One of the problems, and the one that you’re facing, is, ‘What is an acceptable impact?’ ” he said. “When you step back and look at it, the impacts of the power plant are not very great.”

And so it went, as the regional board, at long last, began to sift through the varied opinions, impassioned arguments and scientific rhetoric that have defined the debate over the nuclear plant’s fate. The board will continue to accept written testimony on the issue until Nov. 15, and will take final action at a future meeting.

Edison officials contend that their own self-monitoring studies, not the 15-year study, should be used to determine whether they are in violation of their permit. Their self-monitoring, conducted six times a year, showed that the plant complies with water quality regulations, they testified.

But, in a summary report, the regional board’s staff disagreed with Edison, saying that the company’s methods of collecting data had “an inherently greater chance of failing to detect of violation.” The report said Edison’s monitoring program was potentially “something less than perfect.”

“The fact that no convincing evidence of noncompliance is found by one monitoring effort does not rule out the possibility that such evidence might be found by a different monitoring approach,” the report said. “Staff disagrees with Edison’s contention that only their monitoring data should be used when making any appraisal of their compliance.”

Fish at San Onofre San Onofre Nuclear Generating Station’s Units 2 and 3 use ocean water for cooling purposes, drawing in planktonic fish eggs and larve, juvenile fish and adult fish into the station intake structure. In an attempt to minimize fish losses, the “Fish Return System” pictured below was incorporated into the cooling system. Still, a recent report says, the plank kills 21 to 57 tons of fish a year. 1. Water is drawn into the plant at a rate up to 830,000 gallons a minute. 2. To minimize fish losses, guiding vanes help divert marine life from entering the cooling system. Those that are diverted travel into a fish bypass area of quiet water. 3. The bypass area leads to a large, rectangular bucket. Periodically, an elevator lifts the fish that have collected there to a sluice channel. 4. Water flushing through the sluice channel sends the fish out of the plant, through a 4-foot-diameter pipe that empties in 6 meters of water about 1,900 feet offshore.