San Onofre nuclear plant built to withstand earthquakes

With a nuclear power plant in our backyard it's natural for many San Diegans to wonder if what happened in Japan could somehow happen here. The short answer is that occurrence is very highly unlikely. KUSI's Steve Bosh reports on how our nuclear plants are built to withstand massive earthquakes.

It is unlikely for two reasons, the San Onofre nuclear plant is a different design than those in Japan, and two, Japan's 9.0 earthquake was much more powerful than any earthquake we would, or could, experience in San Diego.

Still, trying to anticipate what Mother Nature will do is, at best, an educated guess. San Onofre is built on the ocean, and it's surrounded by earthquake faults.

Geologist Pat Abbott said that those faults, the San Andreas Fault and the Elsinore Fault, Rose Canyon, Newport, Englewood, and San Clemente Island faults, would only produce between a 7.0-to-7.8 magnitude earthquake.

Those magnitudes are the strongest science can predict for our lifetimes.

The Rose Canyon Fault is the closest to San Onofre. It's just 5 miles from the nuclear reactor. Its one of several fault lines inland, and off shore.

Fortunately, San Onofre was built to withstand a 7.0 earthquake. Nuclear power expert Murray Jennex says, “At San Onofre we analyzed the faults in that region. We analyzed the soils and conditions of that territory and the worst case expected earthquake is a 6.4, so we built for a 7.0 earthquake.”

Murray Jennex was part of the team that designed and built San Onofre. He says the power plants in Japan boil the water directly on the reactor core, which contaminates the steam used to drive the turbine.

San Onofre has pressurized water reactors. “With the pressurized reactor we warm the water over the core similar to a steam generator, which transfers energy to non-radioactive steam, which is then used to drive the turbine and the turbine is clean, it doesn't have contamination,” said Jennex.  

Finally, geologist Pat Abbott says San Diego is the least likely metropolitan area of California to have a major earthquake. “The Los Angeles area has by far the most threats, second most threatened is the San Francisco Bay Area, San Diego is third, significantly, after both of those areas, but that doesn't mean we don't have a threat,” said Abbott.

One other thing worth mentioning, much of Japan is either burning or in a state of collapse except those power plants. They are still standing, still containing the radiation, and the threat to health remains low.

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