State and federal officials are pushing for comprehensive checkups of the San Onofre and Diablo Canyon facilities, which have been cited repeatedly in recent years for safety lapses.

By Ken Bensinger and David Sarno, Los Angeles Times
March 21, 2011

Pointing to Japan’s nuclear crisis, state and federal officials have begun pushing for comprehensive reviews of California’s two commercial nuclear plants, which are near powerful fault lines and have been cited repeatedly in recent years for safety lapses.

If reviewers identify new problems, it could lead to added safety measures — or potentially, delays or denials for renewals of the operating permits for the plants. The two plants, which have been online for decades, supply nearly 15% of the state’s electricity.

“The fundamental question is whether these facilities should be located next to active faults and whether they are operated safely,” said state Sen. Sam Blakeslee (R-San Luis Obispo), who holds a doctorate in geophysics. “With what’s unfolding in Japan, why would anyone approve a permit for these plants to keep operating until every question is answered?”

Federal regulators have cited Southern California Edison’s 2,350-megawatt San Onofre nuclear power plant near San Clemente dozens of times in recent years for safety violations that include failed emergency generators, improperly wired batteries and falsified fire safety data, records show.

At Pacific Gas & Electric’s 2,240-megawatt Diablo Canyon facility on the Central Coast, inspectors in late 2009 found that safety valves designed to allow cooling water into the reactor core in emergencies had been stuck shut for 18 months.

In light of the crisis at Japan’s Fukushima reactors, some state and federal lawmakers are now questioning whether the two utilities have underestimated the severity of earthquakes that could strike the plants.

Less than three years ago, a previously unknown fault was discovered within a mile of Diablo Canyon, and although regulators have asked the companies to conduct further seismic studies, neither has sought permits necessary to do so.

Edison has said that its facility, which houses two reactors, could withstand the equivalent of a magnitude 7 quake and is protected by a 30-foot seawall that is higher than the calculated maximum tsunami for the area.

PG&E, for its part, said that Diablo Canyon’s two reactors could survive a magnitude 7.5 temblor, noting that it’s built on a cliff 85 feet above sea level.

The reactors at these facilities are a different type — which experts say may be more robust — than the one at the Fukushima plant in Japan.

But some lawmakers and regulators point to the still-uncontrolled nuclear crisis in Japan after the massive quake and tsunami there as a strong justification for taking a hard look at the safety of this state’s reactors and for possibly requiring additional retrofitting or even the eventual closure of the plants.

Blakeslee plans to ask PG&E to withdraw its application to the U.S. Nuclear Regulatory Commission to extend permits for its two reactors to operate until 2045 until further seismic studies are completed. Edison has not yet decided whether it would submit its own renewal application.

The NRC licenses each nuclear reactor separately. Licenses for the two reactors at Diablo Canyon expire in 2024 and 2025, while those for San Onofre both expire in 2022.

On Monday, the state Senate Select Committee on Earthquake and Disaster Preparedness will conduct a hearing on nuclear safety, focusing on lessons learned from Japan.

Last week, California’s Public Utilities Commission said it was delaying an April hearing on extending the Diablo Canyon license to take into account events in Japan. And at the federal level, California’s two senators asked the NRC last week to conduct a complete safety review of both facilities.

“Our two plants need immediate inspections and investigations, and they need to look at the increased risk of serious earthquakes, an increased risk of tsunamis and at the safety cultures at those plants,” said Sen. Barbara Boxer (D-Calif.). She noted that more than 7 million people live within 50 miles of San Onofre, while nearly half a million are within that distance from Diablo Canyon.

In 2006, state lawmakers passed a bill calling on the California Energy Commission to review the safety at both plants; the commission in turn urged both utilities to conduct new high-tech surveys to update earthquake risk assessments.

San Onofre’s chief nuclear officer, Pete Dietrich, said SCE was seeking more funds from the state before obtaining permits for new geological surveys. Dietrich said the utility hadn’t decided whether it would apply to renew federal licenses for its two reactors.

Regarding Diablo Canyon, the PUC had asked PG&E to complete a thorough seismic review of the area before submitting its renewal application to the federal government.

But in 2009, PG&E applied to renew the licenses without having performed the new studies. The renewal application, which would allow the plant to operate until 2045, is now being considered by the NRC.

PG&E spokesman Paul Flake said that although the company began work on some new seismic surveys in January, it had not yet sought permits for the most conclusive testing urged by regulators.

“Our license renewal application and our seismic studies are two separate issues,” Flake said.

Dan Hirsch, a nuclear policy lecturer at UC Santa Cruz and president of the Committee to Bridge the Gap, an anti-nuclear group, said California’s reactors were built when the seismic risks involved were not well understood.

In Diablo Canyon’s 1967 application to the PUC, PG&E said the site had only “insignificant faults that have shown no movement for at least 100,000 and possibly millions of years.” Four years later, researchers discovered the Hosgri fault about three miles offshore, which led to expensive retrofitting of the plant.

In 2008, PG&E argued to the state Assembly that it had thoroughly reviewed its local geography and that no further seismic risks existed.

Yet weeks later, the U.S. Geological Survey revealed that it had found a second fault less than a mile from Diablo Canyon. That fault, called Shoreline, is thought by geologists to be capable of producing a magnitude 6.5 quake, while the Hosgri fault is rated up to 7.3.

Geophysicist Jeanne Hardebeck of the USGS helped discover the Shoreline fault. She said that the network of faults in the area appeared to be connected and that she feared a rupture at one could compound into a larger quake.

“There is a real issue of uncertainty when we put a magnitude on a fault,” Hardebeck said, noting that the Japan quake occurred on a fault with a predicted maximum potential quake of magnitude 7.9, but in fact reached 9.

In its 2008 report, the California Energy Commission warned that San Onofre “could experience larger and more frequent earthquakes than had been anticipated when the plant was designed.”

NRC spokesman Scott Burnell said that the quake risk at the two plants was acceptable. “All 104 licensed reactors in the country are meeting the agency’s requirements to operate safely,” he said.

Even so, NRC reports show that Diablo Canyon operated for 18 months with flawed valves that would have prevented cooling water from automatically flowing into the reactor core in an emergency. The problem was discovered in October 2009, and the NRC issued several sanctions against the plant.

The Union of Concerned Scientists, an environmental group, called the event a “near miss,” singling it out as one of the most serious incidents at an American reactor in the last several years.

PG&E spokesman Flake contended that valves could still have been opened manually in an emergency. “PG&E has a very strong safety record,” he said.

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