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Flood and Dambreak Threat To US Nuclear Plants

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PostPosted: Wed Jun 29, 2011 8:15 pm    Post subject: Flood and Dambreak Threat To US Nuclear Plants Reply with quote

This post is a preliminary looks at quantifying the
current flood threat to nuclear plants in the US --Fintan

Flood and Dambreak Threat To US Nuclear Plants

by Fintan Dunne - 29th June, 2011 @ 9:30EST

Not Comparable with Fukushima

Comparisons with Fukushima are too easily made. In Japan there was a
sudden earthquake/tsunami which took out all power supplies and
overcame defensive walls to also flood the diesel backup generators.

By comparison, in the US the plant operators have had months to
prepare and the plants are designed to survive recurring river flooding -
something which happens most every year - not once in a blue moon.

Since this water problem has been slow to build, there has been plenty of
time to double-check and double-up on all backup systems in the light of
the Fukushima issues. A special inspection of all U.S. nuclear plants after
Fukushima found problems with emergency equipment and disaster
procedures - these are now being fixed. So we're much better prepared
than was Fukushima.

Fort Calhoun Nuclear Plant

Another key reason why this is different to Fukushima is that the Nebraska
Fort Calhoun plant has not been operating since April, when it was shut
down for refueling. The reactor vessel fuel rods are under an additional
23 feet of water, around 200,000 gallons.

So the fuel in the core has already cooled of a lot, and would need less
water to prevent a meltdown. Meanwhile cooling continues, with a pump
run on power from the grid continuously running the water through a heat
exchanger to keep the temperature below the boiling point.

If the power grid was lost, there are two 2.5-megawatt emergency diesel
generators --with over two weeks’ diesel fuel on hand. The plant is
currently dry inside and surrounded by about two feet of water.

The plant has also brought in emergency portable pumps and generators
in case the existing ones fail due to any unexpected rise in the flood
water level.

A recent break in a water berm around one plant is actually a positive
development. After the brem broke it was found that some special high
concete walls around generators and switchgear were leaking . These
have been fixed and other similar walls are being checked and retro-fixed.

How Flood Level Affects Nuclear Plant

The Fort Calhoun facility can handle flood waters reaching 1,014 ft.
Flood waters are currently 1,006 ft and expected max is 1,008 feet.

But let's examine the consequences of water levels above 1,008 feet.

At around 1,011 feet, water would overflow the current height of an
earthen levee protecting the electrical switchyard. We would then be
relying on pumps to drain the switchyard while the levee was repaired.
We would have at least two weeks on backup generators to achieve
these repairs.

Water would have to rise to 1,038.5 feet to reach the spent fuel pool,
which holds the plants most recently used uranium fuel.

Let's suppose for reason of flood or failure that the diesel generators
were out of action --causing the reactor water to heat up, and in 36 hours
to start to boiling.

It is estimated it would boil off 12 gallons a minute, so 200,000 gallons
means around 10 days before core temperatures would be dangerpous.

That's 10 days to restore normal cooling or to pump in new water from
a 100,000-gallon storage tank nearby or indeed from the river itself.

Dam and Levee Issues

The Army Corps of Engineers say that less than 1/3 of the upstream
water has been released and heavy rains continue. Levees are failing
regularly and in some cases, one has to travel in excess of 100 miles to
find a bridge or road open to cross the Missouri River.

Counterintuitively, levee failures are a bonus for the nuclear plant,
because their loss leaves less water making it's way downstream.

The major pressing danger for the Ft. Calhoun Nuclear Plant is if the river
experiences a sudden surge of perhaps ten feet due to one or more dams
failing upstream. Further research is required to evaluate the potential for
such a failure.

Another imponderable is heavy and continuous rainfall in the weeks ahead
over and above the normal weather pattern for this time of year. Or even
sudden high temperatures melting snow faster than expected.

However neither of these are as great a concern as a dam failure.

A dam failure would likely severly damage the earthen levee around the
plant and force the operators onto backup diesel power as described

The Fort Peck Dam

Of all the dams upriver, it is the first Fort Peck dam that presents the
greatest chance of triggering a catastrophic flooding and a cascade of
dam failures --according to Bernard Shanks an engineer and consultant
to the Resource Renewal Institute.

Shanks points out that Fort Peck is a old design. A soil-based hydraulic-fill
dam that is the largest of its kind in the USA. He calls it a "flawed design"
and reminds us that it already failed once -during construction.

Hydraulic-fill dams are prone says Shanks to liquefaction — in which
water-saturated soil loses stability --leading to almost instant collapse.

California required all hydraulic-fill dams be torn out or rebuilt — and no
other large dams have been built this way in recent times.

I must stress that a dam failure would damage the earthen levee around
the plant and force the operators onto backup diesel power --but there
is no certainty a dam failure would translate into an inevitable nuclear
contamination incident. I have yet to quantify the issues well enough to
be able to guage the consequences.

An interview with Shanks and an article by him
from the St. Louis Post-Dispatch are below:



The looming Missouri dam flood

By Bernard Shanks | Posted: Tuesday, June 7, 2011 12:00 am

There is very real threat of a flood that will leave St. Louis in chest-high water. The reason: Six old, huge, faulty dams that normally have reserve space for spring snow melt are nearly full now — before the spring floods start. Floodgates that haven't been opened in 50 years have begun to open. Flooding has begun. And the human and economic toll could be ghastly.

Why another flood disaster? Six dams from Fort Peck in Montana to Gavins Point in South Dakota, authorized by the Flood Control Act of 1944, are in the process of failing at flood control. With spring water levels low, they can hold back more than three years of average Missouri River flow — enough to stop the worst floods and protect 750 miles of the Missouri River valley and heartland cities. This year, that is not the case.

Let me give you a sense of scale. These reservoirs are massive. Four of the nation's 10 largest reservoirs are along the Missouri River — Fort Peck, Fort Randall, Garrison and Oahe. Three of these had less than five feet of total storage space behind the floodgates at the end of May. With a combined height of 700 feet, these three dams are nearly full. Melting snow surely will complete the task.

With cities from Wolf Point, Mont., to St. Louis facing record levels of water, hundreds of thousands of people are threatened by the unprecedented opening of floodgates. The greatest fear is the massive Fort Peck Dam, a hydraulic-fill dam that is the largest of its kind.

The Fort Peck Dam is built with a flawed design that has suffered a well-known fate for this type of dam — liquefaction — in which saturated soil loses its stability. Hydraulic-fill dams are prone to almost instant collapse from stress or earthquakes. California required all hydraulic-fill dams be torn out or rebuilt — and no other large dams have been built this way since.

At three miles wide, Fort Peck Dam last opened its floodgates 36 years ago. By the end of the first week in June, the U.S. Army Corps of Engineers will be releasing a record spill of water. The corps recently answered the question of possible failure with a statement the dam is "absolutely safe." It may be the largest at-risk dam in the nation.

Downstream, Garrison Dam never has had to use its floodgates since the dam was constructed 50 years ago. By mid-June, the corps plans to dump water equal to a good-sized river. The same is true for Oahe Dam, the next one downstream. Since the reservoirs are nearly full, the corps has no choice.

Effective flood control from six large dams is no longer an option. As a corps representative said, "It now moves us into uncharted territory."

We must all pose a question of national significance to the corps: What if Fort Peck Dam should fail?

Here is a likely scenario: Garrison, Oahe and three other downstream earthen dams would have to catch and hold a massive amount of water, an area covering nearly 250 square miles 100 feet deep. But earthen dams, when overtopped with floodwater, do not stand. They break and erode away, usually within an hour. All are full.

There is a possibility a failure of Fort Peck Dam could lead to a domino-like collapse of all five downstream dams. It probably would wreck every bridge, highway, pipeline and power line and split the heartland of the nation, leaving a gap 1,500 miles wide. Countless sewage treatment plants, toxic waste sites and even Superfund sites would be flushed downstream. The death toll and blow to our economy would be ghastly.

Years after Katrina and the New Orleans levee breaks, professional engineers and a federal court judge ruled theCorps of Engineers was to blame.

Are we once again at the brink of a massive corps failure? The corps is infamous for management errors, caving to commercial pressure and losing sight of its primary mission. This pending threat is so huge that it is gambling with the nation's security.

The corps is placing the nation at risk, and if the dams fail, Leon Panetta, who will become secretary of Defense later this month, will have the great Missouri Flood Disaster on his desk. And the entire nation will demand answers as to why the U.S. Army Corps of Engineers did not avert disaster with more economically and ecologically sound methods of flood prevention.

Bernard Shanks, an adviser to the Resource Renewal Institute, has studied the six main-stem Missouri River dams for more than four decades. He has worked for the U.S. Geological Survey and served as director of the Washington Department of Fish and Wildlife. He has written three books on public land policy and is completing a book on the hazards of the Missouri River dams.

Copyright 2011 STLtoday.com. All rights reserved.


There was an official response
to Bernard Shanks' article:

"A statement released by Col. Robert Ruch, commander of the corps
Omaha District, said that "there is no evidence to suggest an an
emergency situation at any of our dams
, and all projects are operating
within their design parameters."

He added that all of the corps' dams have had similar pool levels in the
past and that increased monitoring of the dams has not found any


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PostPosted: Thu Jun 30, 2011 2:53 pm    Post subject: Reply with quote


Then came the slide of '38


The slide. No one has forgotten it. It was a quiet day, Sept.22, 1938, and work on the dam was going at a rapid pace. The dam had been completed just two weeks before, but there was murmuring among some of the men that something was wrong with the dam. The daily inspection of the embankment hinted at a problem.

Survey crews were deployed to assess earth movement and to inspect the core pool. (The core pool was the pool on top of the dam, into which dredge material was pumped. As the water slowly drained out of the core pool, sediment settled below, thereby forming the dam.) Although the pool hadn't moved, the upstream pipeline shell ran lower than it should have.

The day before the slide, the railroad tracks showed no signs of movement, so the work continued in the area. By evening, the situation had changed. At least two men suspected a problem was in the offing the night before the slide. Lewis F. Kao recalls putting in his 4 p.m. to midnight shift on the south (upstream) side of the dam. "That night the dam had started to shift. There was a 6-foot bow in the railroad track," he remembers.

The next shift discontinued dredging in that area. James W. "Monty" Montfort also recalls the night before the slide. "I was foreman of a crew laying quarry stone on the four to twelve shift," wrote Montfort. "We were completing a tier of stone at the extreme east abutment and were to move the dragline... the dike section at the west end of the dam. "Water was coming up through the gravel and we could hear gurgling sounds beneath us."

At 7 p.m., we began working off the mats; and as the weight of the machine was transferred onto the gravel, it began to sink and water rushed up around the tracks. "We moved in a bulldozer and a loadmaster and began building up with small mats. At about 11 p.m., we had managed to reach solid ground. The graveyard shift relieved us and moved out with the dragline. Our crew was muddy, wet, exhausted and glad to go home.

The next afternoon, the slide occurred and the east upstream section of the dam was gone. On that tragic day at 1:15 p.m., even as District Engineer Maj. Clark Kittrell inspected the problem area from his passenger seat in a sedan, something strange and terrifying occurred.

Suddenly, the earth started shaking, dredge pipes and railroad tracks started shifting and sinking and a massive section of the dam swung out into the upstream as if a great earthen gate hinged on the east abutment.

Machinery and men alike were swallowed up in the moving, muddy hell and 5 million cubic yards of earth slid out into the Missouri River, forming its own island.

Eight men lost their lives, and six are still buried somewhere in the dam. Some who lost friends in the slide consider the dam a large gravestone for those men whose bodies were never recovered. Word spread through the area quickly that the "dam was going to give," and people packed belongings quickly and headed for higher ground.

The Slide of 1938 is the single most memorable event to occur during construction of the dam, according to dam workers employed on that fateful day in 1938.

What caused the dam to slide? To this day, many say the core pool was too deep. Others say the dam was being filled too fast and there was not enough time for the water to drain out. Some blamed the bentonite seams beneath the dam.

Soon after the rescue efforts were halted, engineers conducted a battery of complex tests to determine the cause of the slide. Samples were taken from as deep as 300 feet. A board of blue chip consultants was formed to study the problem, and it was their decision that work should continue on the dam. The board, which consisted of Joel D. Dustin (chairman), Arthur Casagrande, Irving W. Crosby, William Gerig, Glennon Gilboy, W. H. McAlpine, C. W. Sturtevant, Thaddeus Merriman and Warren Mead, met for a total of 20 days over a five-month period, studying 26 sets of technical data.

On March 3,1939, the board returned its report, which said the slide's occurrence was "due to the fact that the shearing resistance of the weathered shale and bentonite seams in the foundation was insufficient to withstand the shearing forces to which the foundation was subjected. The board's seven-man majority recommended completing the dam, and work began once more. The base of the dam was widened, thereby flattening the slope, and the embankment was raised with rolled earth.

A berm was added and sheet pile joined the old and new cores. A reinforced concrete wall was placed in front of the intake structures, and a protective two-mile dike was built. Piezometers and relief wells were installed in the dam.

The slide delayed completion of the dam for a little more than a year, but on Oct.11, 1940, the last load of material was dumped on the dam, topping it out at 250.5 feet.


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PostPosted: Mon Jul 04, 2011 1:04 pm    Post subject: Reply with quote

By-the-book flood control panned

Sunday July 3, 2011 - By David Hendee - World-Herald Staff Writer

Five months ago, Army engineers in a downtown Omaha office building fed computers with the latest snowfall data and predicted another potentially wet year along the Missouri River.

Simultaneously, the public works director in a little South Dakota city 450 miles upstream — and just below the towering face of Oahe Dam — crunched the numbers himself.

He was stunned.

By Brad Lawrence's seat-of-the-pants calculations in Fort Pierre, the Mighty Mo appeared poised to unleash “a flood of biblical proportions.”

Lawrence fired off an email to the American Water Works Association in Washington, D.C. He warned that river communities along the Missouri should prepare for flooding and stock up on sandbags.

“This may be one for the record book,” he wrote on Feb. 3.

Lawrence's hunch was prophetic, but not widely known.

As record Missouri River flows from dams in Montana to Nebraska breach levees, force evacuations and inspire around-the-clock flood-fighting along the nation's longest river, frustrated victims and others are asking if the Army Corps of Engineers' by-the-book management of its dams during a year of heavy snowfall and record rainfall contributed to the unprecedented flooding.

Water and climate experts, emergency managers and elected officials up and down the river were mixed in their reviews of Army engineers' decisions and actions — guided by their 432-page, congressionally approved and court-tested Master Manual, the bible of Missouri River management.

The manual is the problem, say Missouri U.S. Sens. Roy Blunt, Republican, and Claire McCaskill, a Democrat, who promise congressional review.

Fix the flood first, then investigate, says Rep. Steve King, a Republican whose western Iowa district includes some of the hardest hit communities and farms.

“I can't lay the flood at the feet of the corps,” he said.

There will be an opportunity for fact-finding, but an unfortunate set of circumstances coincided to create the flood, said Al Berndt, assistant director of the Nebraska Emergency Management Agency.

“I can't second-guess what the corps did,” he said.

No one could have predicted that the semi-arid high plains of Montana would be drenched with off-the-charts rains that poured millions of acre-feet of water into the upper Missouri in late May, said Gina Loss, a National Weather Service hydrologist in Great Falls, Mont.

All of eastern Montana — a region roughly the size of Nebraska — received more than 200 percent of its normal May rain. The eastern third of the state measured rainfall at more than 300 percent of normal. A gauge in the Judith River basin, a Missouri tributary, collected nearly 11 inches of rain where 3.6 inches is normal. Some places measured rains of more than 15 inches.

Half of Montana got nearly a year's worth of rain in a few days,” Loss said. “It was incredibly rare. I can't emphasize that enough.”

A nearly 12-month supply of water — based on historic runoff averages — poured into the basin above Sioux City, Iowa, during May and June combined.

Adnan Akyüz, North Dakota's state climatologist in Bismarck, said the snowiest winter ever and the second-wettest spring in western North Dakota — a region that usually receives meager precipitation — created perfect conditions for flooding.

It would be easy to predict runoff without dams because water that flows into a river flows out, he said.

“But when you inject humans and dams, they have more impact on flooding than the climate,'' he said. “The idea behind dams is to release or hold water based on what's expected. Sometimes forecasts are true. Sometimes they're not true.”

Loss said the cool spring in the Montana mountains has been a blessing because it prevented historic snowpack from melting on schedule and joining the big rainfall runoff in May.

“We would have had a much bigger flooding problem than we're dealing with,” she said.

Lawrence, the Fort Pierre official, didn't base his flood warning on the expectation of historic upstream rainfall in the Missouri. Rather, he anticipated flooding in the Mississippi and Ohio Rivers, plus the James and Big Sioux Rivers — both Missouri tributaries — in eastern South Dakota.

Widespread flooding in those places, he said, would compel the corps to hold back water in its system of six Missouri River reservoirs to alleviate downstream flooding, especially at the mouth of the Missouri — at the Mississippi.

The reservoirs would fill to capacity. Once full, the corps would be forced to release massive volumes of water, creating flooding. Lawrence said the corps failed to lower its reservoirs enough to meet normal runoff conditions.

Corps officials dispute his claims, saying they don't operate the Missouri to accommodate the Mississippi. They also said the full flood-control capacity of the Missouri dams was available by late January — and that it was unclear until early April this would be a year of higher-than-normal reservoir releases.

By early May, the corps accelerated its releases of floodwater and said 2011 had the potential to be the second-highest runoff season in 113 years of recordkeeping.

Lawrence said the water content of Plains snowpack around Garrison Dam in North Dakota caught his attention. He said he thinks the corps' calculations don't accurately factor how much water is held in snowpack on the Plains.

He noted, for example, that Oahe Reservoir — the second-largest corps impoundment nationally — gained 4 feet more in elevation during March than the corps forecast. The lake then rose nearly a foot more in April than projected, he said.

“That's not a minor miscalculation or misinterpretation,'' Lawrence said. “That's a very gross miscalculation. It's an astronomical miscalculation of the Plains snowpack runoff.”

Jody Farhat, who regulates the dams as chief of the corps water management office in Omaha, said Plains snowpack received added attention this year because it played a significant role in last year's flooding.

King said he understands that people want to blame someone for the flooding.

“There's more water than we've ever seen coming down the Missouri,” he said. “It's an ocean. It's eight to 11 miles wide in places. We will lose businesses, and we will lose people.''

King, whose earth-moving business has done levee work on Missouri tributaries, said the corps could not have prevented the flood by lowering the water level in its dams without changes to the manual or “unless they had someone who was clairvoyant and could convince people they knew the flood was coming.”

King said he has asked the corps to produce a hydrologic model showing how it would have managed the reservoirs to avoid flooding, based on what is now known.

“I see that as a baseline to changing the Master Manual,” King said.

Stuart Maas of Bellevue, who is an owner of a hunting lodge in the flooded bottomland near Hamburg, Iowa, said the corps should not hide behind its manual.

“That is a terrible excuse,'' he said, “to say that a piece of paper limits what you can do when your own judgment says it should be done.”

Maas said the river flooded his land for nearly three months last year.

We had a dress rehearsal last year,” he said. “The river was talking to us.

Maas said the corps should lower levels of the largest upstream reservoirs to create more space for spring runoff and flood control. He doubts it will happen, he said, because barge interests in Missouri would fear having too little water in the reservoirs to release for floating vessels in the summer.

A 2003 court decision says that flood control and navigation are the dominant functions of the reservoir system. The corps says flood control is its top priority.

Berndt said Nebraska emergency managers were aware of expected high flows in the Missouri this spring and have been fighting minor lowland flooding in Boyd and Knox Counties for more than a year.

“We knew we were going to have some flooding, but we didn't expect this magnitude,” he said. “The problem is the duration of flooding. It's unprecedented.”

Lawrence said he hopes that honest assessments are made after the flooding to be better prepared in the future.

“This isn't a ‘gotcha' thing,” he said. “I'm not an expert. Like Yogi Berra said, ‘You can observe a lot just by watching.'”


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PostPosted: Tue Jul 12, 2011 6:50 pm    Post subject: Reply with quote

Earthen levees on Missouri River at risk

Rural areas face more damage, experts warn, as river
continues to rise
and saturated levees lose stability.

BY JOSH FUNK • Associated Press | Posted: Sunday, July 10, 2011

OMAHA, Neb. • Experts say several levees along the Missouri River, especially older ones in rural areas, are at risk of failing this summer as massive amounts of water continue to flow through the river system from upriver reservoirs, but chances of such failures in urban areas remain remote.

So far, most levees have held along the 811 miles the Missouri travels from the last dam at Gavins Point in South Dakota to its confluence with the Mississippi River near St. Louis.

But engineers who have studied past floods say the earthen levees in rural areas are at greater risk.

"Most of the levees are agricultural levees. They're not engineered. They're just dirt piled up," said David Rogers, an engineering professor at Missouri University of Science and Technology.

A few levees have failed, but most of the flooding thus far has covered more than 560,000 acres of mostly rural land. The water has forced some evacuations, but the extent of the damage may not be clear until it recedes. That's not expected to happen until the fall as the Army Corps of Engineers says it needs to continue releasing substantial amounts of water from upstream reservoirs inundated with heavy spring rains and melt from an above average Rocky Mountain snowpack.

The corps on Friday said the amount of water held in reservoirs has started to decline slightly, but Col. Robert Ruch, who leads the corps' Omaha office, said there are no plans to significantly decrease the amount of water being released from dams because any major rain in Montana or the Dakotas would force the corps to increase the amount of water being released.

"We're still in a very active flood fight," Ruch said.

The corps predicts the Missouri River will remain 5 to 7 feet above flood stage in much of Nebraska and Iowa and may rise as high as 10 feet above flood stage in Missouri until at least mid-August.

The corps predicts that the river will eventually rise high enough to flow over some 18 to 70 levees, mostly in rural areas of southeast Nebraska, southwest Iowa and Missouri. Other levees will become saturated, and water can erode their foundations, seep underneath or find other flaws to exploit.

A saturated levee may lose stability, potentially causing it to crumble, as one did in June near Hamburg, Iowa, allowing floodwater to cover several miles of farmland and threaten the town. Flaws in levees, such as animal burrows, can allow water to flow through and eventually destroy the structure.

"At times like these, this is when we find out where the weak spots are," said Erik Loehr, an associate professor of engineering at the University of Missouri.......


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PostPosted: Tue Jul 12, 2011 8:14 pm    Post subject: Reply with quote

Playing Belle, MO this Saturday, played a flood relief show a month or so ago in Sikeston, MO.

While flying back from Utah over the Mississippi back in May, it was astounding. Didn't even look like a river, looked like a massively long lake.

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PostPosted: Tue Jul 12, 2011 8:33 pm    Post subject: MO better blues Reply with quote

Rumpl4skn wrote:
Playing Belle, MO this Saturday, played a flood relief show a month or so ago in Sikeston, MO.

While flying back from Utah over the Mississippi back in May, it was astounding. Didn't even look like a river, looked like a massively long lake.

No requests for "Cry me a river" I'll bet Twisted Evil

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