Part 1:Seismic Risks to CGS–What the NRC Doesn’t Want You to Know

Part 1:Seismic Risks to CGS–What the NRC Doesn’t Want You to Know

A long but very well written article on the seismic risks of CGS which affects as we have seen in other posts, Hanford and the world. Please take the time to read this entire post by Gar Smith. We will post this into 4 parts to make reading easier and a bit less overwhelming regarding the enormity of the problem we face with CGS.

Nukequake: The Columbia Generating Station Is a Seismic Timebomb

By Gar Smith

The landscape in eastern Washington State is deceptively tranquil — a rural 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.

Part of the sprawling Hanford complex along the Columbia River.

Part of the sprawling Hanford complex along the Columbia River.

Like a picnic blanket spread over a minefield, the Columbia Basin’s flat meadows and rolling hills veil an oft-times explosive past. Much of this geological record was buried beneath an epochal slurry of soil released when a massive ice dam repeatedly burst from 1,000,000 to 13,000 years ago. More than 40 great Missoula Floods have inundated this region.

By the time the first white pioneers rolled into the territory that was to become Washington State, there was little evidence to suggest the record of turmoil buried deep beneath the soil. The first non-native settlers to arrive in southeastern Washington’s Pasco Basin encountered a seemingly tranquil vista of grass-fringed hillocks framing the region’s valleys. They gave these landmarks colorful names — Rattlesnake Ridge, Saddle Mountain, Horse Heaven Hills. The first geologists (who arrived much later) initially assumed the rills and ridges were relatively benign — home to little more than shallow faults that posed no great hazard to the farmers and ranchers who came to populate the area.

From the air, however, planes equipped with remote-sensing LIDAR (Light Detection And Ranging systems that use laser range finders to scan the ground surface) would eventually reveal a series of previously unrecognized fault scarps associated with the east-west linear ridges now known as the Yakima Fold and Thrust Belt (YFTB). And there were other clues: strikingly dissimilar kinds of rock cohabiting on adjacent sides of an exposed scarp; deposits of “colluvium,” layers of soil turned topsy-turvy by ancient tremors.

Then there was the mystery of the region’s roads. In 1979, geologists began to notice that the highways crossing Oregon and Washington State were rising ominously — at the rate of one to two millimeters per year.

Not the best place, you might think, to build a nuclear power plant.

The History of the WPPSS reactor

The Columbia Generation Station (CGS), Washington’s only remaining commercial reactor, sits inside the Department of Energy’s Hanford Nuclear Reservation, a former nuclear weapons production site that spreads over 586 square miles. The CGS facility, which extends over 1,089 acres (1.7 square miles), is the sole survivor of a planned five-reactor complex proposed by the Washington Public Power Supply System (WPPSS). Powered by a General Electric Mark II boiling water reactor, CGS (originally dubbed the Washington Nuclear Power Unit 2, or WNP-2) began operating in December 1984, a mere 15 miles north of Richland, Washington.

Top 10 reasons to close the Columbia reactor.

Top 10 reasons to close the Columbia reactor.

Projected to open in five years at a cost of just under $400 million, construction actually took more than 12 years and racked up a total cost of around $3.2 billion. When the reactor finally started churning out power, its electricity was priced at 6.2 cents per kWh — triple the preferred rate for the average Bonneville Power Authority utility. (From 2000 to 2010 CGS reactor provided just five percent of the Pacific Northwest’s electricity. In 2011, it provided even less, owing to a six-month shutdown for repairs. By 2013, CGS’s contribution to the power grid of the entire Pacific Northwest region had declined to just 3.9%. Meanwhile, the market price of electricity in the Pacific Northwest has fallen to the point that the CGS reactor no longer produces power at a profit — a fact that bolsters the call for closing the reactor and replacing the lost power with electricity from renewable energy installations). In December 2013, Robert McCullough, a leading utility consultant, released an extensive report on the reactor’s economics. McCollough’s investigation showed that it cost $418 million to operate the reactor while the plant produced only $218 million worth of market-rate power.

The fact that only one reactor was actually built suggests why the power system’s initials came to be pronounced “Whoops.” After WPPSS declared bankruptcy and defaulted on its bonds during a $2 billion financial meltdown (at the time, the largest municipal bond default in US history), “Whoops” was enshrined as an official entry in the Barron’s Financial Dictionary. On November 19, 1998, an understandably embarrassed WPPSS Executive Board voted for a name-change, rebranding its operation as “Energy Northwest.” CEO Vic Parrish rushed to assure a skeptical public that: “We are not trying to run from our past, but run toward our future.” Either way, a troubled history and a questionable future clearly had the company’s management on the run.

In 2009, eleven years after its name-change, the industry-funded Institute of Nuclear
Power Operations ranked CGS as one of the country’s two reactors “most in need of
improvement.” Out of the 75 unplanned shutdowns (or “scrams”) that hobbled the US
commercial nuclear fleet that year, CGS accounted for five. Even Brad Sawatzke,
Energy Northwest’s Chief Nuclear Officer, was forced to concede, in an April 29, 2011
interview with a Seattle TV station, that “our one Northwest nuclear reactor has the
worst shut down 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.”

Of course, whenever a turbine fails, the entire nuclear plant stops generating electricity
and becomes an economic liability. No surprise then, that Energy Northwest’s initial
2013 draft ten year budget included funds for a new turbine and a new steam generator.
However, in an apparent move to keep costs down, Energy Northwest removed those
costly purchases and others, $150 million in all, from its printed budget. As a result, the
current budget lacks funds to replace these two critical pieces of equipment.

Quake and Break

Today, the Columbia Generating Station has become the focus of a growing national
debate over the safety of nuclear reactors built in seismic trouble spots. The published studies of seismic lore available to the engineers who designed the WNP-2 only ran from 1974 to 1981. It wasn’t until after construction of the 1,170-Mw atomic reactor was completed that a new generation of geologists began to uncover the region’s uncharted seismic history.

One sign that this might not have been the perfect spot for a nuclear power plant came
in the very first stages of construction. As Energy Northwest explained in a September
2013 press release: “Columbia’s built-in safety margin began with preparation of the
new construction site in the 1970s. The soil at the site was removed to a depth of 65
feet and replaced with structural backfill soil — soil specially engineered… to meet
stringent density requirements.”

In this same press release, Energy Northwest misinformed the public about what really
occurred when three GE-designed Mark I reactors melted down at the nuclear power
complex in Fukushima, Japan. While Fukushima’s reactors “safely survived the March
11, 2011 earthquake,” the company writes, “the facilities were not designed to withstand
the effects of the tsunami.” In fact, the earthquake knocked out the outside power
needed to keep the reactors from melting down. Without off-site power, emergency
batteries can only run the cooling systems protecting the reactors and radioactive waste
storage pools for a matter of hours.

In addition, earthquake-caused damage to piping and other critical safety systems at
Fukushima Daiichi Unit 1 may very well have triggered the first meltdown, even before
the tsunami hit. On May 15, 2011, the Tokyo Electric Power Company (TEPCO, the
plant’s operator) quietly conceded there might have been some pre-tsunami quake
damage to key facilities and critical pipes.

In his 2007 book, TEPCO: The Dark Empire, Katsunobu Onda both predicted and
explained the mindset behind the official post-meltdown evasions of 2011: “If TEPCO
and the government of Japan admit an earthquake can do direct damage to the reactor,
this raises suspicions about the safety of every reactor they run.” This kind of industrialpolitical
collusion should concern everyone living in the Pacific Northwest for the simple
reason that the CGS Mark II reactor was designed by General Electric, the same
company that designed and built the Fukushima Daiichi reactors. Fukushima’s Unit-6
building houses a GE Mark II reactor, a BRW-5 design that began operating in 1979.
The US Nuclear Regulatory Commission has determined that the Mark II containment is
subject to the same danger of catastrophic hydrogen explosions that occurred with the
Mark I reactors at Fukushima. (On September 20, 2013, Japan’s Prime Minister Shinzo
Abe ordered TEPCO to decommission the Mark II reactor.)

Faulty Assumptions

The classic caveat for great undertakings has long been: “Don’t build your castles on
sand.” The modern equivalent of this warning could well be: “Don’t build atomic reactors
in earthquake zones.”

When the CGS reactor was originally designed, geologists thought earthquakes were
largely consigned to the sea-facing portion of Washington, west of the Cascades. They
believed the faults beneath the inland ridges of the Columbia Basin were
inconsequential and “uncoupled” — short and shallow fractures that, because they were
believed to be unconnected, posed little in the way of risk. It wasn’t until the 1980s that
geologists (and the public) began to get a glimpse of the extent of the dangers buried
beneath their feet.

An additional wake-up call occurred in 2009 when a swarm of more than 1,000 quakes
shook the eastern half of the sprawling Hanford Nuclear Reservation — a complex
dotted with radioactive waste storage tanks. While the Hanford quakes were no larger
than magnitude 3.3, they struck close to the surface and produced a significant peak
ground motion. This activity suggested that the nearby Yakima Ridge Fault actually
extended into the Hanford Reservation all the way to the Wooded Island in the
Columbia River — a finding that raised concerns about the safety of the CGS reactor,
as well.

When CGS was designed, geologists were only aware of six local faults — Umtanum
Ridge-Gable Mountain, Rattlesnake Ridge-Wallula Alignment, Horse Heaven Hills,
Rattlesnake Hills, Yakima Ridge, and Saddle Mountain. After the nuclear reactor was
constructed, another half-dozen faults were identified — Frenchman Hills, Manastash
Ridge, Toppenish Ridge, Columbia Hills, Hog Ranch-Naneum Ridge, and the Hite Fault.
By 2011, three new faults east of the Cascades had been identified. All were assessed
as “more active” than would previously have been expected. Casting a worried eye
toward Hanford’s shuttered nuclear facilities and waste-storage tanks, seismologist
Annie Kammerer observed: “Frankly, it is not a good story for us. The plants were more
vulnerable than they realized.”

In 2013, the Washington and Oregon chapters of Physicians for Social Responsibility
(PSR) hired geologist Terry L. Tolan to conduct a survey of the region’s seismic
research. While geologists had become aware of several newly discovered faultlines, no
one had considered how these findings might apply to the CGS reactor. Tolan’s review
reiterated that the CGS site is surrounded by at least 12 significant faults that are more
numerous, much longer, far deeper and potentially more destructive than anything
imagined when the reactor was first designed. These known faults have the potential to
rattle the reactor with forces double those the CGS reactor was designed to survive.
Two faults identified after the CGS was built actually bracket the reactor to the north and
south. The southern fault, identified by the recent earthquake swarm, runs within 2.3
miles of the nuclear core.

Most of the concern in Washington State, however, has concentrated on just three fault
systems, some of which have importance in considering the risk to the CGS nuclear
reactor.

The Yakima Fold and Thrust Belt.

This formation, located east of the Cascade Range, is part of a tectonic region that is far more seismically active and interconnected than once believed. The Yakima Fold courses through the sagebrush flats of central and eastern Washington, a stretch of territory that includes the Hanford Site. The Yakima Fold-Thrust Belt (YFTB) consists of a series of generally parallel ridges running west-to-east. The result of tectonic compression, each of these ridges are cored by a major fault system.

In the mid-2000s, the US Geological Survey (USGS) found historic evidence that the
YFTB had produced at least seven magnitude-7 earthquakes that created ground
motions exceeding the CGS reactor’s design limits. Another troubling discovery: The
Rattlesnake Hills-Rattlesnake Mountain structure has registered a significant surface
rise — having moved upwards at a rate of 60 to 72.5 meters per millennium. (In more
familiar terms, that would be around 197 to 238 feet per 1,000 years or about 20 to 24
feet every century.)

The Seattle Fault.

In 1999, USGS scientists Robert Bucknam and Brian Sherrod reported finding physical evidence that the 44-mile Seattle Fault that traverses metropolitan Seattle was still active. LIDAR mapping confirmed the existence of a Holocene-era fault scarp at the point where the Seattle Fault crosses Bainbridge Island.

A reverse fault beneath Seattle caused a major magnitude-7 earthquake between A.D.
900-930. Another quake along the reverse fault that projects through Tacoma, violently
rearranged the ground surface between A.D. 770 and 1160.

Given this history, the Seattle Fault now is considered to pose a major seismic hazard
to the city of Seattle. This shallow “thrust variety fault” is not a single crack but a series
of eight fault strands that extend east and west over a five-mile path between downtown
Seattle and Vashon Island. The Seattle Fault zone also contains three or more southdipping
thrust faults.

The South Whidbey Island Fault.

The region’s most dangerous surface fault is believed to be the South Whidbey Island Fault (SWIF). A USGS study revealed the fault’s hazards in the mid-1990s. Unlike most faultlines, which parallel coastlines and mountain ranges, the SWIF actually crosses southeast through the Cascade Range, reaching as far as the Tri-Cities in southeast Washington.

The SWIF initially was estimated to run 40 miles through the southern portion of
Whidbey Island but the USGS has discovered that the SWIF actually is composed of a
complex band of fractures extending 50 miles. With a greater fault track running 200
miles from Vancouver Island to the Cascade foothills, the SWIF is one of the largest
fault systems in the region — second only to the offshore Cascadia fault in terms of size
and risk. Geologists have uncovered evidence of four sizable shakes along the SWIF
over the past 16,000 years. They set the most recent at around 2,700 years ago.

We now know that the Seattle Fault is not isolated. It is, in fact, part of the SWIF.
Together, they form a system of faults that extends southeast across the Cascade
Range and as far as the Hanford Reservation. A 2011 USGS report traced the
Umtanum Ridge fault to the west and found that it extended through the Cascade
Range and linked with the active Seattle and SWIF fracture zones in the Puget Sound
area. The USGS research nearly doubled the length of the Umtanum fault — from
around 77 miles to 124 miles. Evidence now suggests the faults and folds of the
Umtanum Ridge extend northwestward through the Cascade Range where they merge
with the Seattle and South Whidbey Island faults near Snoqualamie Pass — 22 miles
east of Seattle.

“The faults don’t just end in Puget Sound,” USGS research geophysicist Rick Blakely
noted. “Our hypothesis is that many big faults in Eastern Washington go through the
Cascades.” Blakely’s research suggests that the active faults west of the Cascades
actually extend 250 to 300 miles from the Olympic Penisula and through the Cascade
Range where they merge with the basalt formations of Eastern Washington, at least as
far as Pasco — a town located about 20 miles southeast of the CGS reactor.

The discovery of “tectonic connections” between the seismically active Puget Lowlands
and the basalt that underlies the Hanford Nuclear Reservation is alarming. As the
Pacific Northwest National Laboratory (PNNL) noted in a 2012 report, larger faults can
produce more slippage, which can generate larger quakes and more intense ground
motion. PNNL emphasized that long faults — especially those with a longer “recurrence
rate” — are an even greater threat since they can generate higher-magnitude seismic
events “due to long-term build-up of stress.”

“What we’re dealing with is a system of faults that we think are linked,” says USGS
geologist Brian Sherrod. “But if you have a fault system that’s 200 kilometers long and
you rupture half or a third of it, that’s a big earthquake. That’s a magnitude 7.5.”
PNNL scientists have determined that tectonic stress on the YFTB is being released by
geophysical rotation, folding, fracturing, and faulting. So far, thanks to a favorable
alignment, the YFTB has been able to handle the offshore Cascadia Subduction Zone’s
growing pressures as the submerged Juan de Fuca rock plate pushes its way beneath
the continental plate at the rate of 1.6 inches per year. The relentless east-northeast
pressure forces fractured elements of the Pacific Northwest lithosphere to slowly grind
together and rotate in a clockwise direction. Imagine a massive shovel (the Juan de
Fuca plate) being slowly rammed beneath a gargantuan 50-to-155-mile-thick paving
stone (the North American plate).

There was another surprise awaiting the geologists. Contrary to long-held opinion, the
faults beneath central Washington were not shallow. Instead, they were found to
originate deep within the crust, extending more than 12 miles below the surface. “The
faults that formed the ridges are much more dangerous than anyone realized,” Sherrod
summarized. “It’s a fundamental rethinking of the seismic risk over there.”

The Seattle Fault, the SWIF and a Geological “Train Wreck”

Even without an earthquake, the Pacific Northwest is in constant motion, moving about
half-inch per year. And, with every creeping millimeter of movement, the pressures
continue to mount inside the offshore Cascadian Subduction Zone, the Seattle Fault,
the Tacoma Fault, and the South Whidbey Island Fault. It is estimated that, since 1700,
the Northwest coast has moved more than 25 feet closer to Japan.

USGS scientist Ray Wells has created an ingenious laminated map with movable
sections that demonstrate how the puzzle-pieces of the region’s geology engage in a
vast and complex contest of slow-motion collisions. As Wells puts it: “It’s a train wreck
on a geological scale.”

If it is a train wreck, then the “locomotive” would be the Pacific Plate, which continues to
chug implacably northward at a rate of two inches per year, pulling much of California
along for the ride. As California bumps into Oregon from the south, the Juan de Fuca
Plate continues to ram into Oregon from the west as it dives eastward beneath North
America. Rotating under strain and pushed northward, Oregon continues to press into
Washington. Unfortunately Washington’s northward progress is blocked by the
unyielding bedrock that underlies inland British Columbia. Pushed from the south and
blocked by the north, Wells explains, the Evergreen State “crumples like a line of box
cars slamming into a mountain.”

It is this unremitting pressure that created the Seattle, Tacoma, and South Whidbey
Island faults. “They are all driven by this north-south compression,” Wells says. “Ditto
for the rumpled ridges and faults of the YFTB in Central and Eastern Washington. The
Puget Lowlands are being compressed by about a quarter of an inch a year. That adds
up to more than 20 feet of crunch since the last time the Seattle Fault fired off. Central
and Eastern Washington are being squeezed at a slightly lower rate. Inexorably, the
pressure is accumulating, loading the Seattle Fault and its associates like springs. The
squeeze on the Puget Sound region is enough to produce a magnitude-7 quake every
500 years.”

A Whole Lot of Shakin’ Going On

Global climate change also effects tectonic activity. The land surface of our planet is a
study of elements in motion. The original singular supercontinent called Gondwana
began to break apart more than 180 million years ago. The individual continents that
resulted have been in motion ever since. As the globe warms, polar ice melts, sea
levels rise. As pressures on surface and subsurface tectonic plates shift, earthquakes
can become more frequent. One Australian study of more than 386,000 earthquakes
between 1973 and 2007 shows seismic activity increasing fivefold over a 20-year span.
According to Tom Chalko, the scientist who conducted the survey: “The most serious
environmental problem we face . . . [is] rapidly and systematically increasing seismic,
tectonic, and volcanic activity.”

A “History of Megaquakes” compiled by Safer Coastlines lists just three superquakes
(measuring magnitude 7.9 or more) in the entire 18th century and only two in the 19th
century. By contrast, there were ten megaquakes in the 20th century and just the first 12
years of the 21st century have seen seven megaquakes (all ranging between magnitude
8 and magnitude 9).

It is important to note that the earthquake records from the 17th and 18th centuries are
spotty and incomplete. Still, the first decade of the current century has seen an unusual
number of super-quakes — a magnitude 9 quake in Sumatra in 2004 caused a tsunami
that killed 227,898; a magnitude 8.8 quake in Chile in 2010 killed 521; a magnitude 7.0
quake that left more than 300,000 dead in Haiti; a magnitude 7.0 quake in New Zealand
in 2010 was followed by a magnitude 6.3 aftershock in 2011; the magnitude 9.0
megaquake that hit Fukushima in 2011 (the fifth largest quake in the past 110 years)
was followed by a magnitude 7.3 quake in October 2013. All of these monster quakes
have occurred along the “Ring of Fire,” the seismically active zone that rings the
continents facing the Pacific Ocean.

Despite this appearance of a troubling trend, USGS geophysicist Andrew Michael
insists that “overall, the pattern is random.” Tom Parsons, a USGS geophysicist at the
Pacific Coastal and Marine Sciences Center in Menlo Park, California, agrees. “Based
on the evidence we’ve seen,” Parson says, “we don’t think that large, global earthquake
clusters are anything more than coincidence.”

The International Atomic Energy Agency (IAEA) estimates that 20 percent of the world’s
reactors are currently operating in regions of known seismic activity. In 2008, growing
concern with “beyond design basis” accidents prompted the IAEA to create the
International Seismic Safety Centre. (A “beyond design basis event” refers to any
incident that generates greater stress than a nuclear plant was designed to withstand.)
More troubling news. One earthquake can trigger another and small quakes can
unleash seismic monsters. It can also work in reverse. Some scientists speculate that
the ferocious quake that struck Japan in 2011 also set off small tremors in Nebraska.

Marine geologist Chris Goldfinger, however, contends “the chances of stress transfer
triggering a major quake [over great distances] are low if not nonexistent.”
On the other hand, Goldfinger has noted: “We’re in the middle of a global cluster of
megaquakes…. Everybody’s noticed it. There are seismologists who say it’s not
statistically significant. But it’s happening. The reason it’s downplayed is that nobody’s
figured out a mechanism — how and why they’re happening now.”

Canadian seismologist Dr. John Cassidy has noted that large earthquakes can trigger
smaller earthquakes and smaller tremors can trigger larger quakes. Case in point: some
geologists believe a magnitude 7.7 quake that struck British Columbia’s Graham Island
in October 2012 may have been linked to a magnitude 7.5 quake that struck off Alaska
nine weeks later. In any event, Cassidy concludes: “The potential is there. The same
plate movements are happening today as happened 100 years ago and 1,000 years
ago…. The energy is being stored for more earthquakes in the future. We know that
they’ll happen, we just don’t know when.”

Terry L. Tolan, the consulting engineering geologist hired to assess existing studies that
evaluated potential seismic hazards at the CGS site, notes that, despite these troubling
discoveries, “No seismic structural upgrades have been made at the [CGS] over the
past 30 years, which has dramatically increased the seismic risk.”

Planning for the “Expected” Not the “Unexpected”

The CGS reactor was not designed to survive a specific magnitude earthquake. Instead,
it was built to withstand a particular amount of “ground shaking” that would be produced
by the largest “expected” quake. This phenomenon is measured in “g” (or “gravity”)
forces — a function of the magnitude of the quake at its epicenter and its attenuation
over distance. (A small quake happening nearby could produce the same force as a
much larger quake occurring farther away.) Determining the “g” factor requires two
critical bits of information: knowing the location of any surrounding faultlines and
understanding the potential forces that could be unleashed during a “maximum credible
earthquake.”

The CGS facility was designed to shrug off a “Safe Shutdown Earthquake” with a
ground motion of 0.25g (i.e., one-fourth the force of gravity). As a matter of industry
practice, nuclear reactors are supposed to include an additional “margin of safety”
beyond the established “g-factor.” The NRC, however, leaves it up to the plant’s
engineers to determine the appropriate “margin of safety.” According to the Nuclear
Energy Institute, the margin of safety is supposed to handle a threat “greater than the
largest earthquake and flood ever known for the region.” (The NRC claims that, under
some circumstances, the CGS design should be able to handle a ground motion of 0.6
g.)

Unfortunately, the geologists who advised CGS’ engineering team in the 1970s, lacked
the knowledge about new, longer, deeper faults recently unearthed by a new generation
of quake hunters. Newer, meaner faults notwithstanding, CGS’ ancient Mark II reactor
just isn’t as safe as its operators proclaim. As Princeton University physicist and former
White House advisor Frank N. von Hippel told the Los Angeles Times: “These first generation
boiling-water reactors have the least margin of safety of any reactor design.”

A Note on Richter Readings

While the Richter scale is the most familiar means of ranking earthquakes, its value is
limited since it only references the total amount of energy produced by a quake. Local
ground acceleration is the effect that really matters. That’s why the NRC does not
require nuclear facilities to be built to survive quakes of a given magnitude. Instead,
they are required to withstand a particular level of ground motion at the site. This threat
level is referred to as a “Safe Shutdown Earthquake.” As the NRC explains, when a
SSE strikes, “all structures, systems, and components important to safety are designed
to remain functional.”

This standard may seem a bit wishful. It not only links three incompatible concepts —
i.e., “safe,” “shutdown,” and “earthquake” — it further seems to presume that there will
never be such a thing as an “Unsafe Shutdown Earthquake.”

The Richter Scale was devised by Cal Tech professor Charles F. Richter in 1935.
Richter’s iconic instrument traced the effects of ground tremors using needle-like pens
that recorded resulting amplitudes on reels of paper rolling off the drums of
seismographs. The science has since gone digital. Today, geologists commonly gauge
quake activity in terms of Moment Magnitude — a direct measure of the energy
released based on the strength of the rock that ruptures, the area of the fault and the
average amount of slippage.

Like the Richter Scale, the Moment Magnitude Scale is logarithmic, with each full step
of the scale representing a ten-fold increase in ground movement — i.e., a magnitude 7
quake would be ten times more powerful than a magnitude-6 event. This force can be
expressed as the explosive equivalent of a chemical detonation. Let’s compare two
recent examples. The magnitude 7.0 earthquake that devastated Haiti in 2010 packed
the wallop of 480,000 tons of TNT. The magnitude 9.0 Tohoku-Oki quake that
unleashed a tsunami on Japan in 2011 released a force equal to the detonation of
480,000,000 tons of TNT — one hundred times more powerful than the Haiti quake.
While Moment Magnitude is useless for assessing small, short-duration quakes, it also
fails to fully account for the force of larger quakes that can roil the ground for much
longer periods. A better scale would simply measure the energy released by the quake.In this case, however, each step up the magnitude scale would mark not a ten-fold
increase in earth-rattling force but a thirty-two-fold increase.

Misplaced Epicenters: Grounds for Concern

When the CGS atomic plant was still on the drawing boards, there were only two known
historic temblors that drew concern — one in 1936 and a larger one that struck in 1872.
In 1872, one of Washington’s largest quakes rumbled into the Cascades with a force of
magnitude 6.5 to 7.4 and sent massive landslides tumbling into the Columbia River.
More recently, a window-cracking magnitude 5.7-to-6.1 quake in 1936 snapped brick
chimneys and created 200-foot-long fissures in the soil of the Walla Walla Valley along
the Washington-Oregon border.

The location of the larger jolt became a matter of serious debate. For those who wanted
to see the CGS reactor built where it now sits, it was better to site the 1872 quake as far
from the Hanford Site as possible. Reactor advocates pinned the epicenter of the 1872
quake in the North Cascades, 180 miles away. With the more troubling 1872 shaker
conveniently pushed to the far horizon, WPPSS’ engineers would only need to focus on
potential impacts of the smaller 1936 “Milton-Freewater” quake, whose epicenter had
been placed 55 miles southeast of the Hanford Site. Looking back, University of
Washington geologist Eric Cheney reflected: “It would have been comical if it wasn’t so
serious.”

The NRC ultimately had to intervene to settle the dispute over the location of the 1872
quake and appointed a mediator named Howard Coombs to resolve the conflict.
Coombs, however, wasn’t a totally disinterested player. He had previously served as a
paid consultant for numerous nuclear power projects. Under Coombs’ direction, the
parties ultimately agreed to locate the quake’s epicenter close to the Canadian border
— a decision that pleased WPPSS and simplified the engineering challenges. As
Cheney observed, Coombs “found a place to park it where it wouldn’t be a problem and
everyone was happy.”

The NRC gave the green light for the reactor’s construction based on the risks
associated with the smaller 1936 quake. (The USGS rated the 1936 event as
magnitude 5.9 quake with an estimated ground acceleration of 0.22 g.)

The next step was to estimate the “potential seismic risk” from any unknown faults that
might lie within a 16-mile radius of the planned reactor site. An assessment was
performed and it produced an assumption of “potential” risks. From this, an analysis
was derived. It was this analysis that was used to assign a “Safe Shutdown Earthquake”
target for the CGS, which was set at a peak ground motion of 0.25 g (or one-fourth the
force of gravity).

The State of Washington’s Geology

In wasn’t until after the CGS reactor went operational in 1984 that scientists began to
discover that Washington’s seemingly placid landscape masked a troubling and
rambunctious past. As A.C. Rohay and S.P. Reidel, two Pacific Northwest National
Laboratory scientists, explained in 2006:

“The Columbia River Basalt Group forms the main bedrock framework of the area.
These rocks have been folded and faulted over the past 17 million years, creating broad
structural and topographic basins separated by anticlinal ridges of the YFTB. Sediment
of the late Tertiary has accumulated in some of these basins. The Hanford Site lies
within one of the larger basins, the Pasco Basin…. Bounded on the north by the Saddle
Mountains and on the south by Rattlesnake Mountain and the Rattlesnake Hills. Yakima
Ridge and Umtanum Ridge trend into the basin and subdivide it into a series of
anticlinal ridges and synclinal basins. The largest syncline, the Cold Creek syncline…, is
the principal structure containing the U.S. Department of Energy (DOE) waste
management areas and the Waste Treatment Plant (WTP).”

In essence, the DOE’s WTP — and much of the Hanford Reservation — sits
precariously atop a layer-cake of sediments dating from the Miocene, covered with
vestiges of the Pliocene Ringold Formation, topped with Missoula Flood gravels,
infiltrated with sands and silt of the Pleistocene’s Hanford Formation and capped by
more recent deposits accumulated during the Holocene. This stacked-card-deck of
sediments can act to amplify the slipping and shaking “ground motion” during a large
magnitude earthquake.

Washington State, it turns out, is even more seismically compromised than California.
The Evergreen State stands at risk from three distinct forms of quakes: shallow, deep,
and mega. 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 (some 27 years after Howard Coombs’ panel issued its verdict), Bakun and
several scientific colleagues uncovered clear evidence that the disputed 1872 quake
was not located 180 miles away but actually involved a shallow fault on the southern
end of Lake Chelan, a mere 99 miles from the CGS — nearer by half.

Bakun also set the magnitude of the quake at 6.8 — noting that the margin of error
would range from 6.5 to 7. Other seismologists have placed the force of the quake at
magnitude 7.4.

The Lake Chelan quake rattled residents all the way from Eugene, Oregon, to British
Columbia. It was a large rumble that affected at least 151,000 square miles and may
have been felt as far north as Alaska. The USGS concluded the damaging impacts of
the resulting ground acceleration extended to the southeast, well beyond the Hanford
nuclear site. This ground motion acceleration likely would have produced seismic forces
greater than the CGS reactor was built to handle.

Clearly, had the CGS existed when the Lake Chelan quake occurred, it most likely
would have sustained moderate to severe damage.

Energy Northwest insists that its reactor — though 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 7.5 quake — eight
times more powerful than a 6.9 quake — would be a different matter.