Joshua Adam Hicks contributed to this report.
California’s two active nuclear power plants sit adjacent to the Pacific coast, giving rise to safety concerns in light of this week’s earthquake and subsequent tsunami that left one of Japan’s nuclear facilities on the brink of a meltdown.
California’s coastal plants, San Onofre, in San Diego County, and Diablo Canyon, in San Luis Obispo County, are built to withstand ground accelerations worse than those that ravaged Japan. But questions remain about how they would stand up to a tsunami.
“The Japanese Fukushima site had a double hit — an earthquake larger than had been anticipated and a tsunami larger than had been anticipated,” said Burton Richter, a Nobel Laureate in physics and a professor at Stanford University.
“The earthquake was not the problem,” he added. “The tsunami was. In Japan, the earthquake engineering was superb, but the tsunami protection was not adequate. Their sea wall was not high enough to protect the site from flooding, and it was the flooding that knocked out the emergency core cooling system.”
Still, Richter said California residents have no reason to be concerned. “The reactors here are different, and their location differs too.”
The two California plants are located several hundred miles south of the Bay Area. The map below gives the approximate locations of California’s major fault lines. (Story Continues Below)
View Nuclear Power in California with Major Fault Lines in a larger map
The 26-year-old Diablo Canyon nuclear plant sits on a bluff 85 feet above sea level, while the 42-year-old San Onofre facility is located 50 feet above sea level, with a 30-foot tsunami wall for added protection.
The U.S. Nuclear Regulatory Commission requires that all nuclear facilities be able to withstand the most severe natural phenomena historically reported in their regions.
The San Onofre facility, for instance, is built to survive a ground acceleration of up to 0.67 meters-per-second-squared, otherwise known as g-force. Experts estimate that the earthquake in Japan caused a ground acceleration somewhere between 0.25 and 0.35 meters-per-second-squared, in comparison.
Maps of California’s geology show that it differs from Japan’s. In California, few faults exist offshore, which lowers the risk of a catastrophic wave the size of the one that hit the Japanese coast.
Nuclear energy proponents say nuclear facilities provide one of the cleanest forms of energy available, but the risk of catastrophe remains high, and scientists are yet to develop succinct protocols for safe disposal of waste.
Critics of nuclear power remain skeptical that the energy plants are as safe as their operators claim.
“In our state, our vulnerability increases as we learn of more and more new fault zones off our coast,” said Rochelle Becker, executive director of the Alliance for Nuclear Responsibility.
Becker emphasizes that Diablo Canyon is located within about 3 miles of four active faults, while San Onofre sits in an area where tsunamis and coastal erosion could be a concern.
Pacific Gas and Electric, which operates the Diablo Canyon facility, said that its tsunami wall is robust; but Japanese authorities made similar claims before the wall that protects the Fukushima Daiichi plant fell.
Still, Richter claims that nuclear power plants are a relatively safe means of generating electricity.
“All energy systems are dangerous, and nuclear power is one of the least dangerous,” he said. “People are more frightened of a single large event than they are of a series of small events that lead to more death and destruction.”