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One reactor was already off that day, part of a planned refueling outage. Operators rapidly shut down the other. Only a tiny amount of radiation leaked out — small enough, authorities would say, that human health was never endangered at the plant or in nearby San Clemente.
But with that alarm, the San Onofre nuclear power plant, whose selling point was its 24/7/365 reliability, suddenly wasn’t so reliable any more.
Something remarkable happened that day. Southern California’s largest electricity source, capable of powering 1.4 million homes, was turned off.
That was January.
Now, six months later, the nuclear plant that’s supposed to always be on is still off and will be until at least late August. No date for restarting it has been set, sending state energy officials scrambling to fill the gap.
To make up for the lost power, a shuttered power plant in Huntington Beach has reopened and the state has expedited other projects to stabilize the electricity grid. Still, San Diego Gas & Electric, which gets 20 percent of its power from the plant, warns that rolling outages are possible during emergencies this summer and is calling for customers to conserve. Meanwhile, the plant’s outage could cost hundreds of millions, a tab that Southern California Edison, San Onofre’s majority owner, is likely to try to pass on to electricity consumers across the state.
It’s a serious incident, one that has attracted fresh attention to a nuclear plant that had just begun to turn around after years of heightened federal scrutiny. San Onofre has a dubious track record.
The federal Nuclear Regulatory Commission began formally flagging concerns at the plant in 2008, citing its failures to provide adequate instructions to employees, weaknesses in ensuring oversight and problems quickly addressing safety issues. Edison replaced its top nuclear official in 2010, part of a management shakeup that improved operations. Still, San Onofre’s on-site employees
have made more allegations of wrongdoing this year than at any other nuclear plant in the country.
Between 2008 and today, the NRC received the most allegations from San Onofre’s workers. At some nuclear plants, the NRC validated one or two concerns. At San Onofre,
the federal watchdog substantiated 62 complaints, including concerns that workers didn’t feel comfortable raising safety issues without fear of retaliation. The NRC in 2010 sent a stern warning to Edison, the plant’s operator, to ensure workers were encouraged to talk about safety problems.
While it isn’t clear whether any connection exists between San Onofre’s troubled history and the current outage, the mere fact that the plant has had so many problems for so long reflects poorly on it, said David Lochbaum, nuclear safety director at the Union of Concerned Scientists. When workers don’t think high standards are being enforced, they tend to become more tolerant of potential problems, Lochbaum said, because they believe there’s less accountability.
Lochbaum likened the situation to a defendant with a long criminal record showing up yet again in court. Their record doesn’t automatically mean they’re guilty, but it doesn’t help, either.
“They may be disassociated, but when you have that other baggage, you can’t ignore it,” Lochbaum said.
San Onofre’s current problems have been traced to the plant’s steam generators, vital parts that were replaced only two years ago. They’re so essential — and so costly — that if they need to be replaced yet again, ratepayer advocates say the nuclear plant might simply be run at reduced power until its operating license expires in 2022 and then closed.
“It’s just a hugely expensive expenditure,” said Matthew Freedman, staff attorney at The Utility Reform Network in San Francisco. “And San Onofre has a recent history full of problems and surprises. So one could predict that even if the steam generator problem works itself out, another problem would be waiting around the corner. “
San Onofre’s safety problems began drawing attention in 2007. A fire prevention specialist responsible for hourly patrols around the plant had deliberately falsified inspection records for years. In 2008, a safety battery was discovered to have been disconnected for four years.
Concerns began mounting. Whistleblowers alleged they’d been fired for raising safety questions. The Nuclear Regulatory Commission added an extra on-site inspector. The NRC flagged the plant for its problems. San Onofre stayed under the ominous federal warning for four years. It was a serious threat to the plant: Improve or else. Federal regulators have shut down at least one nuclear plant that didn’t heed their order.
Edison committed to doing better. It hired a new overseer for the plant and shook up its management. Change was evident. No more so than earlier this year, when the NRC at last lifted the flags on the plant.
But that was March.
And San Onofre was shut down when it happened.
Photo by Sam Hodgson
These power lines coming out of San Onofre carry 20 percent of San Diego’s electricity.
Peter Dietrich, Edison’s top nuclear official, sounded impressed.
It was Feb. 18, 2011, and Edison had just recently completed a monumental project, replacing San Onofre’s four steam generators, the largest components of the nuclear plant. The project was a costly investment in San Onofre’s future. From start to finish, it had taken 10 years and cost $671 million.
When Edison flipped the switch to turn the plant back on at 2:56 a.m. on that February day, Dietrich called it “a moment of pride” for San Onofre’s 2,600 workers. They had successfully pulled off a major upgrade that could keep the plant running for decades to come. The project would save customers $1 billion over 10 years, Dietrich promised.
The effort wasn’t routine, and it was fraught with risk. The generators had to be manufactured in Kobe, Japan, shipped across the Pacific, barged to San Onofre and slowly, ever so slowly, moved inside wide holes carefully cut in the nuclear plant’s concrete containment domes.
Opening containment domes had proven disastrous elsewhere. A similar project in 2009 at a nuclear plant north of Tampa, Fla. cracked a concrete dome. Repairs will keep that facility offline until 2014.
San Onofre’s upgrade went smoother, even if not perfectly. Flaws were found in two generators before they left Japan, where they were manufactured by Mitsubishi Heavy Industries. Inspectors discovered a five-inch-long crack in one. Both had welding defects. But the generators were fixed before making the long trip across the Pacific.
Once installed, the gigantic new generators, which weigh 640 tons apiece, began their essential function: Helping the plant produce electricity.
Here’s how it works. After nuclear fission heats water in the plant’s reactor core, that super-hot, radioactive water leaves the reactor and passes through thousands of thin tubes in the steam generators, before eventually returning to the reactor. It’s a closed cycle. Radioactive water doesn’t get out.
As the water passes through, those thin metal tubes conduct heat, warming water inside the generator. That turns into steam, which turns turbines that make electricity.
The tubes are purposely thin, so they transfer heat efficiently. But they’re not supposed to break or leak. If they fray and radioactive water leaks into the rest of the steam generator, it can escape into the environment.
That’s what happened when the high radiation alarm sounded at San Onofre on Jan. 31. One of the thin metal tubes sprung a leak.
The generators hadn’t been operating a full year. But tests showed those thin tubes were prematurely wearing out. Since the January shutdown, Edison has closed more than 1,300 of the almost 39,000 steam tubes in San Onofre’s generators.
While Edison said one of San Onofre’s reactors could start again in late August, no timeline has been announced for the other. First, the problems will have to be fixed to assure federal regulators and the public that the tubes won’t continue wearing out early.
Even if the plant is able to run again, Edison may reduce its output to prevent the tubes from deteriorating further. But producing less power could complicate the plant’s economics. Other nuclear plants confronted with the same problem have opted to replace their generators or close altogether. In June, Edison CEO Ted Craver allowed for the possibility that San Onofre would need new generators. He told the Los Angeles Times the decision to restart the plant would be one of the toughest calls of his career.
The generators themselves are covered under a $137 million warranty from Mitsubishi. But that wouldn’t come close to covering the cost of starting over on a $671 million project.
No matter what happens, one thing is clear: The steam generator replacement at San Onofre, once so highly praised by Edison officials, has turned out to be a disaster.
Graphic by San Diego Magazine
Back in 2004, San Onofre’s existing steam generators were getting old. And though they were supposed to last the life of the plant, Edison claimed they wouldn’t and proposed a major effort to replace them. New generators would boost San Onofre’s reliability. They’d also boost returns for Edison’s shareholders.
Like with any big-ticket utility company project, California electricity customers were asked to pay the bill. This turned into a fight at the California Public Utilities Commission. Ratepayer advocates and even San Diego Gas & Electric, which owns 20 percent of the plant, argued that replacement generators weren’t needed yet.
An attorney for SDG&E said in regulatory filings that Edison “grossly exaggerated” the likelihood the old generators couldn’t last longer and used pessimistic, hyperbolic projections SDG&E called a “scare tactic.” SDG&E attorney James Walsh wrote in a brief that two of the four generators would likely run until 2017, if not longer. The other two could run until at least 2011, Walsh said.
The thin tubes now so problematic in the new generators weren’t wearing out as fast as expected in the old ones. Edison, in its replacement push, hired an expert to forecast the likelihood of the tubes degrading. When the forecast suggested they could last longer, Edison subjectively tweaked the findings, based on what it said was industry experience.
In its final decision, the utilities commission noted that Edison’s tweak was unusual, saying the company could’ve sought federal approval to extend the generators’ lives, but didn’t.
Still, the commission approved the project. Regardless of exactly when they started up, the commission said new generators were needed to keep San Onofre running until its license expired in 2022.
Project opponents made arguments that today seem prescient. SDG&E warned that Edison’s forecasts for project costs at San Onofre were historically unreliable. And because roughly 15 percent of the United States’ nuclear plants had sustained year-long outages in the last 20 years, The Utility Reform Network asked state regulators to consider whether the generator replacement project would be cost-effective if such an outage occurred at San Onofre. (It wouldn’t be, said Freedman, the utility watchdog attorney.) The group also sought a cap on future operating costs at the plant.
A preliminary decision from the Public Utilities Commission included that cap. The final approval didn’t.
“They said we were being paranoid,” Freedman said. “But sometimes being paranoid means you’re right.”
Another nuclear watchdog, the Alliance for Nuclear Responsibility, proposed that the generator project be delayed until San Onofre cleaned up its record with federal regulators. That, too, was rebuffed.
“If you don’t have a safety culture that knows how to follow directions specifically and write directions specifically for these sorts of projects,” said Rochelle Becker, the alliance’s executive director, “you’re just asking for problems.”
Rob Davis is a senior reporter at Voice of San Diego. You can contact him directly at firstname.lastname@example.org or 619.325.0529.
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