CA Panel Weighs Nuclear Safety After Quake

Wednesday, March 23, 2011 @ 05:03 PM gHale

California state lawmakers want the state’s utilities to delay efforts to relicense nuclear power plants until the companies complete detailed seismic maps to get a true picture of the risks posed by earthquakes and tsunamis.

In light of the disastrous earthquake and tsunami in Japan, state senators raised questions about whether California’s nuclear plants can withstand a major natural catastrophe.

Lawmakers also questioned whether the utilities have been dragging their feet on conducting three-dimensional seismic studies called for in a 2008 state report to assess the risks posed by offshore faults.

Pacific Gas and Electric Co. (PG&E) applied to renew its license to operate the two reactors at Diablo Canyon Power Plant near San Luis Obispo, which expire in 2024 and 2025.

“I would ask sincerely that PG&E suspend or withdraw that application” until completing the additional seismic mapping, said Sen. Sam Blakeslee, R-San Luis Obispo. He said he would pursue legislation to thwart the utility until it completes the mapping.

Blakeslee in 2009 introduced a bill that would have required the utility to meet that and other requirements; it won unanimous support in the Legislature but then-Gov. Arnold Schwarzenegger vetoed it.

Lloyd Cluff, a seismic expert for PG&E, said work started in October for shallow mapping and the utility will apply in April for a permit for deep mapping down to 10 kilometers below the surface.

“We’re doing it as we speak,” Cluff said.

California gets a total of about 12 percent of its power from the Diablo Canyon and the San Onofre nuclear plants.

Japan’s plants were not able to handle the ground movement or wave heights, said Steve David, director of site services at Diablo Canyon. It just was not in the design.

Diablo Canyon and San Onofre can survive much larger forces, utility representatives testified.

The utilities contend the design and location of the plants protect them from the most serious natural threats considered possible at the sites.

Bedrock is the anchor for Diablo Canyon, which has safety systems and emergency reservoirs located at 80 feet or more above sea level. San Onofre enjoys protection from a 30-foot seawall.

Corbett noted that seismic experts have estimated there is a 2 percent to 3 percent chance of a major earthquake in California each year, and a 46 percent chance of a quake with a magnitude of 7.5 or greater within the next 30 years.

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