The safety of a nuclear power plant located up the coast from Santa Barbara County was the source of discussion Tuesday among the Board of Supervisors.

Government officials have urged Pacific Gas & Electric Co., which operates the Diablo Canyon Nuclear Power Plant, to halt renewing its license until more seismic studies can be done on fault lines in the area.

When the nuclear reactors at the Fukushima Daiichi nuclear power plant in Japan were compromised from a tsunami and corresponding earthquake in March, concern was raised among residents on the Central Coast and beyond about the Diablo Canyon Nuclear Power Plant in Avila Beach.

PG&E said last month that it intends to expedite completion of the seismic studies and that it had asked the Nuclear Regulatory Commission to delay final action on the license. A number of faults exist near the plant, including the Shoreline Fault, which was discovered in 2008. The company maintains that the plant has an adequate safety margin to withstand any seismic activity that might occur from faults in the region, including the Shoreline Fault.

Jearl Strickland, senior regional manager of PG&E, was the senior civil engineer at Diablo Canyon and talked with county supervisors about the safety issues of the plant. His presentation focused on the Fukushima Daiichi event and how it compares to Diablo Canyon, listing all the precautionary measures the facility has built into its design.

The tsunami disabled all of the Japanese plant’s safety systems, Strickland said, and “within a short period of time, the plant did not have adequate cooling.” he said Japanese officials estimate that it could take nine months to a year until full containment.

Strickland said that looking at the Richter magnitude scale isn’t always the complete picture of what a structure can withstand. The type of fault and proximity from that fault are critical, too. Looking at the ground acceleration is also important. Diablo Canyon is designed for almost twice as much ground acceleration as its Japanese counterpart, Strickland said.

The Japanese plant was designed to withstand a 21-foot tsunami, but saw one that was closer to 33 feet. Diablo Canyon is designed for to withstand 35 feet of water, which Strickland said is the maximum projected tsunami height.

The plant also has six diesel generators, three for each unit. The minimum required to keep each unit operating is one generator, he said, with underground stored fuel for each. Steam-driven feedwater pumps are a backup coolant for the facility that would continue to provide water to the plant for about 20 days if needed, he said. Diablo Canyon also has its own fire department on site.

Strickland said the Central Coast plant is located 85 feet above sea level, while Fukushima Daiichi plant was 20 feet above sea level. However, fault structures offshore near Diablo Canyon are not a significant tsunami source.

But some of the half-dozen speakers Tuesday weren’t swayed by Strickland’s presentation, including public commenter Judith Evered.

“I think we just have to keep our fingers crossed that we don’t get an earthquake that’s more than 7.5,” she said, calling for Diablo Canyon to be shut down. “Why take risks? The technology is not fail safe.”

Other public speakers cited cancer risks, expense and danger of natural disasters.

Local attorney Marc Chytilo said the opposition to the plant wasn’t fear-mongering.

“We are a down-wind community,” he said of Santa Barbara County. Should a disaster occur, “we will have a matter of hours. We need to be prepared for those episodes.”

There’s a 10 mile exclusion zone around Diablo Canyon for evacuations, and Supervisor Janet Wolf asked if there had been any discussion about expanding that zone in the wake of the Japanese disaster.

“I think it’s a good question for the NRC and whether they’re looking at changing that,” said Michael Harris, the county’s emergency operations chief.

Wolf also said she would be interested to know what effect a Diablo Canyon disaster would have on Santa Barbara County water sources, such as Cachuma Lake.

“I want to make sure we’ve got plans in place should this occur,” she said.

Officials from the NRC are scheduled to meet with government leaders in San Luis Obispo on June 16 to further discuss the relicensing effort and safety concerns.

— Noozhawk staff writer Lara Cooper can be reached at lcooper@noozhawk.com. Follow Noozhawk on Twitter: @noozhawk or @NoozhawkNews. Become a fan of Noozhawk on Facebook.