The leak of radioactive material that contaminated groundwater beneath the San Onofre nuclear power plant has not reached a drinking-water source in San Clemente, according to test results announced Tuesday.
City officials shut down the drinking-water well last week as a precaution after learning that cancer-causing tritium had been detected two miles away, beneath the San Onofre Nuclear Generating Station in northwest San Diego County.
"The news is good: The test results came in this morning, and there is no tritium in the well," said David N. Lund, San Clemente's public works director.
Tritium, an isotope of hydrogen, occurs naturally in the environment but is also a byproduct of nuclear fission.
The city gets 3% of its potable water from that well. Much of it is used to irrigate San Clemente's city golf course, but some supplies drinking water to homes in the southernmost part of town, Lund said. The city gets the rest of its water from the Colorado River and Northern California.
City officials want to learn more about the area's geology and hydrology and its relation to the groundwater beneath San Onofre before putting the well back into service, Lund said. It was unknown how long the work would take.
Sandwiched between Camp Pendleton and the Pacific Ocean, San Onofre is the larger of California's two nuclear power plants and can generate 2,200 megawatts, enough power to serve 2.75 million households throughout Southern California. The plant is operated by Southern California Edison and houses two working reactors. A third, 450-megawatt reactor was shut down in 1992 and is being dismantled.
Plant spokesman Ray Golden, who had previously said there was no evidence that the tritium had left the site, said Edison was happy to hear the water testing results. "We will continue to be monitoring here on the site," he said.
The contamination was discovered this month when workers were dismantling the containment dome that housed the inactive reactor.
They discovered that groundwater beneath the reactor complex was tainted with 50,000 to 330,000 picocuries of tritium per liter.
The U.S. Environmental Protection Agency's drinking-water safety limit for tritium is 20,000 picocuries per liter. California has recommended a "public health goal" of no more than 400 picocuries per liter of drinking water, a level that state environmental officials determined could still cause one cancer case per million people exposed.
