Research Shakes Up Seismic Knowledge
New evidence that the Yakima Fold and Thrust belt may be much more seismically active than long thought
could reshape assumptions used in assessments of nuclear safety at Hanford and the Columbia Generating Station.
Brian Sherrod is a professional fault finder.
The United States Geological Survey paleoseismologist scrambles up a shrub-covered hillside outside Yakima, Wash., points a few hundred yards away and describes how a long stretch of slightly off-colored soil could change perceptions of an entire region's earthquake readiness.
Three years from now, when the latest iterations of the USGS's national hazard maps appear, they'll likely include new information about the Yakima Fold and Thrust Belt. That's a crinkled landscape of anticlines and synclines -- hill-like folds of the earth's crust -- spread across Central and Eastern Washington, including the spot where Sherrod now stands and, further east, the home of the Northwest's only commercial nuclear reactor.
A new paper by Sherrod and Richard Blakely accepted for publication May 2 highlights compelling new evidence that the Yakima Fold and Thrust belt may be much more seismically active than long thought. If true, these findings could reshape assumptions used in assessments of nuclear safety, just as regulators try to reassess the controversial energy source in the wake of the March 11 Tohoku earthquake in Japan.
The magnitude 9 Tohoku quake wreaked unfathomable havoc in that country. Buildings collapsed. The ground split and a furious ocean stormed the coast, overwhelming defenses. Roiling, flaming seas of debris marched across cities and farms and deep down river valleys, upending houses and decimating one of the most advanced nations in the world.
Barely before the Japanese could grieve, the sight of smoke at the Fukushima Daiichi nuclear plant stoked new concerns. Soon, news of hydrogen explosions and lost power and overheating fuel rods emerged. Emergency responders pumped seawater in a seemingly quixotic attempt to prevent a radioactive release. Officials declared and expanded evacuation zones. The one country that perhaps most viscerally understood the power of the atom found itself haunted by it again.
Fukushima's shadow stretched across the Pacific as anti-nuclear activists and industry proponents alike quickly mobilized.
Attention almost immediately turned to the Pacific Northwest, where the Cascadia Subduction Zone has in the past and could again produce quakes similar to what struck Japan.
Nervous thoughts also wandered to a tumbleweed-strewn compound known as the Hanford Site hundreds of miles inland, where nearly six decades ago, as part of the Manhattan Project, it provided the plutonium used in the bomb dropped on Nagasaki, Japan. Throughout the Cold War, experiments on Uranium and other elements were conducted at Hanford, where nine nuclear reactors produced plutonium for weapons. Operated by the U.S. Department of Energy, the nearly 600-square-mile Hanford Site is now North America's most contaminated place. A massive cleanup there will last years.
The region also hosts the Columbia Generating Station, which provides 1,150 MW of electricity on land at Hanford leased from the DOE. A joint operating authority known as Energy Northwestand consisting of 27 member public utilities districts from across Washington runs the plant (Once known as the Washington State Public Power Supply System -- WPPSS, or "Whoops"as the public often joked -- changed its name to Energy Northwest in 1999 to distance itself from a massive municipal bond default that left additional reactors unfinished).
Industry leaders and regulators alike tried to reassure Americans that nuclear power plants across the U.S. are safe.
"At the moment, based on all the information we have, we are convinced that all the plants that are operating in the United States are operating safely," Nuclear Regulatory Commission spokesman Victor Dricks said.
After sustained public and political pressure, on April 1 the NRC assembled a task force to examine nuclear safety.
"We're conducting a 90-day review of the safety of all of the nuclear plants in the country in response to the events in Japan; a quick look to determine if there are things that we need to do, actions we need to take and things we see there," Dricks said. "Later, when we've had a chance to thoroughly review all the lessons we learned from Fukushima, we will conduct another review."
Meanwhile, the commission continues ongoing reviews of plant licenses, including Energy Northwest's application to extend the Columbia Generating Station's operating license to 2043 (the plant's current license expires in 2023). Two plants -- Indian Point in New York and Palo Verde in Arizona -- have been re-licensed after the events at Fukushima.
So far, the Columbia Generating Station's license application has proceeded smoothly, with a draft environmental impact statement from the NRC scheduled in June. However, NRC letters sent as part of the licensing process reveal the NRC had multiple questions for Energy Northwest about the assumptions it used to develop its response plan for potential accidents. Among the questions: Why did Energy Northwest continue to use 15-year-old studies as the basis for its earthquake preparations, when much more up-to-date information about the region's seismic profile were available from the USGS and Hanford itself?
Now two months after the Tohoku quake, NRC staff stymied an effort by a coalition of citizens' groups who want the commission to suspend other activities until it fully reviews lessons learned from the disaster. On May 2, NRC staff recommended that the commission deny the group's emergency petition.
As a plant currently under review, the Columbia Generating Station became one of the petition's focuses. The document said Portland, Ore.-based Northwest Environmental Advocates was "extremely concerned" about the implications of the Fukushima crisis
"They are particularly concerned about the implications of the Fukushima accident in light of earthquake risks to the Columbia Generating Station based on new findings of a structural zone that kinematically connects faults in central Washington with faults in the Puget Sound, the entirety of which may be seismically active," the petition said. "The Fukushima accident also highlights the hazards associated with facility mismanagement, which has been a chronic problem at the Columbia Generating Station."
According to Sherrod, who's not involved with the petition, the findings it refers to are the same ones from his and Blakely's paper.
Though the field is dynamic and growing, Dricks said in-house seismic experts are up to speed on earthquake data and research. Seismic and other hazards are too important only to deal with during plant licensing, Dricks said.
"All of the nuclear plants in the country are required to have designs that address and take into account the most severe natural environmental hazards that have occurred in the area," Dricks said.
After considering the worst case scenario, the commission then adds in a margin of error to its requirements of plant operators to account for unforeseen circumstances. The commission also studies historical data to determine hazards. If new data suggests inadequacies in the existing design of an NRC-regulated plant, the commission and the licensee analyze whether additional action is necessary. If the task force now reviewing nuclear plant safety has any recommendations to change current severe accident mitigation alternatives, or SAMA, reviews, then that could impact NRC's review of Columbia's license, Dricks says.
Meanwhile, the commission pays attention to current operating conditions at nuclear plants across the world.
"We're always looking for information that can be applied to all U.S. reactors, and we analyze information that could become available from any incident, including Japan," Dricks said. He said the 90-day review launched after Fukushima is looking at all aspects of NRC activities and will provide any lessons learned from the disaster.
NWEA Executive Director Nina Bell said her organization's concern isn't limited to earthquakes, or any single risk at the Columbia Generating Station. Rather, she said, Fukushima illustrates that natural disasters can combine with human error, poor siting, inadequate design and operational mistakes into cascading problems.
"Northwest Environmental Advocates believes that nuclear power is inherently an experimental technology and that there are any number of unforeseen triggering actions that are likely to take place," Bell said.
Bell, who said it was "shocking" that the NRC issued Vermont Yankee's new license so soon after the Fukushima event, said the public's being left out of important decision-making by a public body, though she's not surprised by the NRC staff recommendation to deny the petition
"Since the Nuclear Regulatory Commission seeks to the extent possible to eliminate public involvement in its licensing proceedings, the reaction by the NRC staff is, indeed, not a surprise," Bell said. "At the same time, it is still rather amazing that this huge nuclear accident in Japan is continuing, we still don't know all of the cascading failures that occurred, and the NRC staff is taking the position that, essentially, we in the United States have nothing substantial to learn from that accident."
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