Seismic Uncertainty at Diablo Canyon

 March 17, 2011

By  BC Editorial Team

PG&E wants to extend nuclear plant’s life despite incomplete earthquake analysis

The California Public Utilities Commission has postponed an April hearing to consider extending the Diablo Canyon nuclear power plant’s life by 20 years because of the unfolding disaster in northeastern Japan.

The 20-year extension was requested by Pacific Gas and Electric Company, which owns and operates the plant. The waterfront facility contains two nuclear reactors and is located 180 miles south of San Jose. PG&E had asked the commission to extend the Diablo Canyon’s life from 2025 to 2045.

Nuclear power plant operators receive their operating permits from the U.S. Nuclear Regulatory Commission, and that agency says it expects to publish a ruling on PG&E’s application to extend Diablo Canyon’s permits in 2012 or later. The CPUC’s role is critical, however, because the agency is responsible for approving ratepayer funding needed for the plant’s continuing operations.

“The hearing will be re-scheduled after the CPUC accepts comment on safety lessons learned as a result of the nuclear problems Japan is facing following the tsunami,” CPUC spokesman Christopher Chow wrote in an e-mail. “We do not know at this time what is going to be covered.”

Even before last week’s earthquake and tsunami in Japan, the proposal to relicense the 26-year-old facility was controversial. Updated seismic studies planned by PG&E are not expected to be completed before 2014. In 2009, then-Gov. Arnold Schwarzenegger vetoed a law unanimously approved by the Legislature that would have compelled PG&E company to undertake specific seismic studies recommended by the California Energy Commission.

The studies are needed in part because the U.S. Geological Survey announced in 2008 the discovery of previously undetected fault line, the 15-mile Shoreline Fault, which runs within 330 yards of Diablo Canyon. Without those studies, PG&E cannot say for certain whether an earthquake along that fault or others nearby would result in a nuclear meltdown.

PG&E’s inability to account for seismic risks that could affect Diablo Canyon is reminiscent of its failure to document safe operating pressures for many its natural gas transmission pipelines. On Wednesday, the CPUC excoriated PG&E for what it called “willful noncompliance” with its order to locate and turn over pipeline records this week following the Sept. 9 San Bruno explosion.

The CPUC said Thursday that its decision to cancel the scheduled April 13 hearing was unrelated to the company’s gas pipeline problems and sloppy record-keeping.

Three-dimensional modeling of the impact of an earthquake on Diablo Canyon began two months ago, PG&E spokesman Kory Raftery said. He said that more advanced studies of the potential impact of an earthquake, requiring permits for underwater experiments, are also planned.

Those studies will be paid for with nearly $17 million in rate-payer funds and are expected to take three years, according to the California Energy Commission.

“It’s important to remember that Japan has different seismic characteristics and different geographic characteristics than we do,” Raftery said. “Our plant is designed for our specific region.”

The CPUC said it has not determined whether to hold public hearings into seismic and tsunami risks facing the nuclear facility, which has operated in San Luis Obispo County since 1985 or merely accept public comments in writing, Chow said Thursday.

Diablo Canyon was placed on alert by the federal government last week as a tsunami generated by the Japan earthquake made its way toward California. No damage was reported.

Diablo Canyon is one of two nuclear power plants operating in California. The other is in San Clemente in Southern California. A nuclear power plant in Humboldt was shut down in 1976 because of seismic risks.

Critics have raised concerns about Diablo Canyon’s proximity to coastal and inland towns and the heavily-populated Bay Area. With radiation leaking into the atmosphere, Japan has evacuated residents within 12 miles of the Fukushima Daiichi Nuclear Power Station; the United States is reportedly drafting plans to voluntarily evacuate servicemen and women and their families from military bases within 200 miles of the stricken plant because of radiation fears.

Adding to concerns about the safety of Diablo Canyon, the facility operated with some emergency systems disabled for nearly 18 months, according to a Los Angeles Times review of federal reports.

The Huffington Post reported Thursday that PG&E is not required to file an earthquake response plan for the facility. PG&E disputed the story by posting an article on its website quoting a federal official saying that all nuclear plants have emergency preparedness plans for a number of potential disasters, including earthquakes.

State Sen. Sam Blakeslee, a geophysicist with a doctorate in earthquake studies whose district includes the nuclear power plant, cautiously welcomed the CPUC’s decision to cancel the April 13 hearing.

Blakeslee has led legislative efforts to improve safety at the facility. He authored the 2009 law, which was vetoed by Schwarzenneger, that would have required PG&E to undertake advanced seismic studies near the reactors dealing with newly discovered earthquake faults.

“I hope that the PUC’s action to pull the agenda item is about fulfilling their enforcement responsibility, not an attempt to wait for public and political pressure to pass,” Blakeslee said in an e-mail Thursday from the Senate floor in Sacramento.

Communities near the power plant have called for it to be shuttered, fearing accidents similar to the disasters that occurred in 1986 in Chernobyl and this week in Fukushima.

Concerns about the seismic safety at the nuclear power plant were raised Monday during a hearing of the California Legislature’s Utilities and Commerce Committee. They were also raised in a letter sent Wednesday to nuclear regulators by the state’s U.S. senators.

“Roughly 424,000 live within 50 miles of the Diablo Canyon and 7.4 million live within 50 miles of the San Onofre Nuclear Generating Station,” senators Barbara Boxer and Dianne Feinstein wrote in the letter to the U.S. Nuclear Regulatory Commission.

“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. “We ask that the Nuclear Regulatory Commission perform a thorough inspection at these two plants to evaluate their safety and emergency preparedness plans.”

Independent journalist Leuren Moret, a trained geophysicist who authored a 2004 Japan Times article predicting that an earthquake would lead to the nuclear disaster in Japan, said it’s “crazy” to allow Diablo Canyon to continue operating in the seismically active region, which is at the edge of the same tectonic plate that caused the Japan earthquake.

Moret characterized PG&E assurances that the facility is safe as public relations exercises designed to allay public fears.

“That’s what Japan has been telling everybody,” Moret said. “There’s no way that PG&E can guarantee that.”

BC Editorial Team


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