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The landscape of eastern Washington State is deceptively tranquil: a pastiche of vineyards, farms, scrub grass, ridges and windmills. But what appears peaceful and settled in the moment has proven restive and violent over geologic time. Beneath the glacial trough of the Puget Lowland, and extending east through the Cascades to the Columbia Basin, lies a hidden landscape of geomorphic rubble—broken basalt, vast shards of continental rock, volcanic ash and layers of ancient sediment. Like a picnic blanket spread over a minefield, the Columbia Basin’s flat meadows and rolling hills veil an oft-times explosive past.
Not the best place, you might think, to build a nuclear power plant. Especially a General Electric Mark II “Fukushima-style” boiling water reactor.
The Columbia Generation Station, Washington’s only commercial reactor, sits inside the Department of Energy’s Hanford Nuclear Reservation, a former nuclear weapons production site. Powered by a General Electric Mark II boiling water reactor, Columbia began operating in Dec. 1984. In 2009, the industry-funded Institute of Nuclear Power Operations ranked Columbia as one of the country’s two reactors “most in need of improvement.” Of the 75 unplanned shutdowns (or “scrams”) that hobbled the U.S. commercial nuclear fleet that year, Columbia accounted for five. Even Brad Sawatzke, the plant’s chief nuclear officer, conceded in an April 2011 interview that “our one Northwest nuclear reactor has the worst shutdown history in the country.” But, he hastened to add, “most [of the scrams were]… associated with the turbine side of the house and not nuclear.”
Today, the reactor has become the focus of a growing debate over the safety of nuclear plants built in seismic trouble spots. The problem stems from the fact that the seismic studies available to the Washington State Public Power System engineers who designed the reactor only ran from 1974 to 1981, and new faults have been discovered since then.
When the atomic plant was still on the drawing boards, there were only two known historic earthquakes that drew concern. In 1872, a magnitude 6.5 to 7.4 quake rumbled through the Cascades, sending massive landslides tumbling into the Columbia River. In 1936, a window-cracking magnitude 5.7 to 6.1 quake opened 200-foot-long fissures in the Walla Walla Valley along the Washington-Oregon border.
After pro-reactor advocates conspired to “locate” the epicenter of the 1872 quake in the North Cascades (180 miles from the proposed Columbia site), the state’s engineers only needed to focus on potential impacts of the smaller 1936 quake, whose epicenter was 55 miles southeast of the Hanford Site. This convenient relocation of risk enabled the Nuclear Regulator Commission to green-light the reactor’s construction.
In wasn’t until after the 1,170MW reactor went operational in 1984 that scientists began to discover that Washington’s seemingly placid landscape masked a troubling and rambunctious past. Initially, geologists thought the state’s earthquakes were largely confined to the sea-facing portion of Washington, west of the Cascades. They believed the faults beneath the inland ridges of the Columbia Basin were “uncoupled”—short, shallow and unconnected fractures that posed little risk. We now know that much of the Hanford Reservation is transected by several significant faults.
Geologist Bill Bakun offered a dire assessment of Central Washington: “It’s all riddled with faults,” he said. “It wouldn’t surprise me to have a magnitude 6.8 quake anywhere in that region, including near Hanford.” In 2002, Bakun and several colleagues uncovered evidence that located the 1872 quake’s epicenter at the southern end of Lake Chelan, a mere 99 miles from the Columbia plant. Bakun set the quake’s magnitude at 6.8—with a margin of error ranging from 6.5 to 7. (Other seismologists rate the quake at magnitude 7.4.)
The Lake Chelan quake rocked at least 151,000 square miles and may have been felt as far north as Alaska. Had the Columbia energy station existed when the quake occurred, it most likely would have sustained moderate to severe damage.
Energy Northwest (as Washington State Public Power System is now known) insists that its reactor—built to withstand a “very strong” to “severe” 6.5 magnitude quake—could handle a “violent” 6.9 magnitude event “based on conservative practices in design, manufacturing, fabrication and installation, plant structures, systems and components.” But dealing with a magnitude 7.4 quake—nearly eight times more powerful than a 6.9 quake—would be a different matter.
In 2009, a swarm of more than 1,000 mini-quakes shook the Hanford Nuclear Reservation. While the quakes were no larger than magnitude 3.3, they struck close to the surface and produced a significant “peak ground motion.” Casting a worried eye toward the Reservation’s shuttered Cold War nuclear weapons facilities and its aging radioactive-waste-storage tanks, seismologist Annie Kammerer observed: “Frankly, it is not a good story for us. The plants were more vulnerable than they realized.”