If you were an average kid growing up in Southern California in the 1970s and '80s, a nuclear-power plant catastrophe was one of your last worries.
You might be worried about the pain in your lungs from breathing in smog, the brushfire racing down the mountain behind your house, or the trees in the backyard that might topple over on your house in the 70-mph Santa Ana winds. But a nuclear-plant catastrophe, especially one on the scale of what is happening at the Fukushima Daiichi plant in Japan, was far out of mind. If any nuclear disaster was going to take place, we thought, it would have been from Soviet missiles raining down over the nearby air force base.
But the possibility is still real. What happened in Japan drives home the skill of the engineers and others who designed California’s two nuclear-power plants, the power of luck, or a little of both. In light of the Japanese catastrophe, taking a second or third look at these power plants, and perhaps others, is worth it.
Indeed last week, California Democratic Sens. Dianne Feinstein and Barbara Boxer sent Nuclear Regulatory Commission Chairman Gregory Jaczko a letter urging his agency to perform a safety and emergency-preparedness review of their state's San Onofre Nuclear Generation Station and Diablo Canyon Nuclear Power Plant. The commission “formulates policies, develops regulations governing nuclear-reactor and nuclear-material safety, issues orders to licensees, and adjudicates legal matters,” according to its website.
“Although many safety measures have been taken to address potential hazards associated with these facilities, we need to ensure that the risk is fully evaluated,” the senators wrote. Feinstein and Boxer ask Jaczko to answer questions that they say should be a part of the evaluation, including what safety improvements have been implemented at San Onofre and Diablo Canyon since they first went online in the mid-1980s and how the plants have been modified since new faults near the Diablo Canyon plant have been discovered.
The United States Geological Survey discovered the Shoreline Fault in 2008 “within a few miles” of the Diablo Canyon plant, said Eric Greene, senior utilities engineer with the California Public Utilities Commission. The commission regulates a variety of privately owned infrastructure services in the state, including the plants at Diablo Canyon and San Onofre. Both plants were built to withstand earthquakes of a maximum magnitude based on historical and geological evidence, according to Greene.
The San Onofre plant was built to withstand an 7.0 magnitude earthquake, and the Diablo Canyon plant was built to withstand a magnitude 7.5, Greene said. Estimates show that the maximum-intensity earthquake on the Shoreline Fault would be a 6.5 magnitude—well within the parameters for which Diablo Canyon was built. An additional seismic study under way to learn more about the Shoreline Fault should be completed in 2013.
Could what happened in Japan happen in California?
“My understanding is that the Japanese seismic-hazard maps were based on the assumption that the subduction zone near Sendai wasn’t capable of an earthquake significantly larger than magnitude 8.0,” USGS seismologist Jeanne Hardebeck said in an e-mail. She noted that she doesn’t know the specifications to which the Fukushima Daiichi plant was built.
Although the Japanese earthquake overwhelmed expert predictions of what the fault was capable of, Hardebeck noted a crucial difference between what happened in Japan and what could happen off the coast of California. Because the faults are different, earthquakes off Japan often produce tsunamis; earthquakes off the California coast generally do not, said Hardebeck, who discovered the Shoreline Fault.
And maybe that’s the point. Even though California is in a very active earthquake-fault zone, the threat of tsunami is much lower off the its coast than off the Japanese coast. (“Tsunami” is a Japanese word, after all.)
And, theoretically, if not for the tsunami, the nuclear crisis in Japan would not be where it is today. This month’s earthquake knocked out the power at the plant, which led to the threat of a meltdown, but the plant’s backup generators normally would have kicked in to pump the plant’s coolant water, thereby avoiding the current situation. But the tsunami generated from the earthquake overwhelmed the generators, rendering them useless and leading to the crisis.
If what is happening at the Fukushima Daiichi plant is unlikely to happen at the California plants, is it then necessarily to take another look or two at the safety of those plants? Well, yes. Especially if the United States is going to keep nuclear energy as a key energy source for the future, it’s important for people to feel safe.
Even more important, however, given that the assumptions used in the design of the Fukushima Daiichi plant may have been wrong, it’s important for Californians—and all Americans—to look again.
This article appears in the March 22, 2011 edition of NJ Daily.