According to the Japan Nuclear Regulation Authority, Fukushima was reassessed a year prior to the tsunami. It was determined that the plant needed to be retrofitted to withstand a much stronger earthquake. Had the plant been offline or retrofitted, the accident may have been far less severe.It is already known that Diablo Canyon, operated by Pacific Gas and Electric Co. in San Luis Obispo County, may be subjected to 30 percent more ground shaking from nearby faults than Fukushima experienced. The first of several ongoing studies, published last week, states ground shaking at Diablo Canyon can exceed plant design. It is anticipated this will lead to years of more study. The Nuclear Regulatory Commission will then consider ordering upgrades.
Diablo is being allowed to operate during this entire process, as was Fukushima. A federal appeals court is currently considering the legality of the NRC allowing Diablo Canyon to operate outside of its license while the studies are being completed.
The U.S. Geological Survey also released a report last week stating that the chance of an 8.0-magnitude quake in California sometime in the next 30 years has increased from 4.7 percent to 7 percent. The Fukushima disaster was cited as the reason for the USGS study because it involved multi-fault ruptures. Diablo Canyon is located within a few miles of multiple faults, which are the focus of its ongoing study.
Since 1976, California has had, in effect, a moratorium on building new nuclear plants. The San Onofre plant in San Diego was permanently shut down in 2013 after a water leak was found in a reactor tube.
Immediately after the Fukushima accident, the Legislative Analyst’s Office estimated that closing Diablo Canyon would cost tens of billions of dollars a year and cause rolling blackouts.
Full article: Diablo Canyon plant shouldn’t be operating while safety is in doubt (Business Insider)