Your stance on nuclear power

[Docfeelgood]

Fukushima Engineer Says He Helped Cover Up Flaw at Dai-Ichi Reactor No. 4

I did not want to put this in the EQ thread because someone had asked to lay off the nuke plant posts. I think this would be the appropriate thread. Anyway, this is ( if true ) what makes nuke plants so dangerous. Greed.

One of the reactors in the crippled Fukushima nuclear plant may have been relying on flawed steel to hold the radiation in its core, according to an engineer who helped build its containment vessel four decades ago.

Mitsuhiko Tanaka says he helped conceal a manufacturing defect in the $250 million steel vessel installed at the Fukushima Dai-Ichi No. 4 reactor while working for a unit of Hitachi Ltd. (6501) in 1974. The reactor, which Tanaka has called a “time bomb,” was shut for maintenance when the March 11 earthquake triggered a 7-meter (23-foot) tsunami that disabled cooling systems at the plant, leading to explosions and radiation leaks.

“Who knows what would have happened if that reactor had been running?” Tanaka, who turned his back on the nuclear industry after the Chernobyl disaster, said in an interview last week. “I have no idea if it could withstand an earthquake like this. It’s got a faulty reactor inside.”

Tanaka’s allegations, which he says he brought to the attention of Japan’s Trade Ministry in 1988 and chronicled in a book two years later called “Why Nuclear Power is Dangerous,” have resurfaced after Japan’s worst nuclear accident on record. The No. 4 reactor was hit by explosions and a fire that spread from adjacent units as the crisis deepened.
No Safety Problem

Hitachi spokesman Yuichi Izumisawa said the company met with Tanaka in 1988 to discuss the work he did to fix a dent in the vessel and concluded there was no safety problem. “We have not revised our view since then,” Izumisawa said.

Kenta Takahashi, an official at the Trade Ministry’s Nuclear and Industrial Safety Agency, said he couldn’t confirm whether the agency’s predecessor, the Agency for Natural Resources and Energy, had conducted an investigation into Tanaka’s claims. Naoki Tsunoda, a spokesman at Tokyo Electric Power Co., which owns the plant, said he couldn’t immediately comment.

Tanaka, who said he led the team that built the steel vessel, was at his apartment on Tokyo’s outskirts when Japan’s biggest earthquake on record struck off the coast on March 11, shaking buildings in the nation’s capital.

“I grabbed my wife and we just hugged,” he said. “I thought this is it: we’re dead.”

For Tanaka, the nightmare intensified the next day when a series of explosions were triggered next to the reactor that he helped build. Since then, the risks of radioactive leaks increased as workers have struggled to bring the plant under control.

Fukushima No. 4

Tanaka says the reactor pressure vessel inside Fukushima’s unit No. 4 was damaged at a Babcock-Hitachi foundry in Kure City, in Hiroshima prefecture, during the last step of a manufacturing process that took 2 1/2 years and cost tens of millions of dollars. If the mistake had been discovered, the company might have been bankrupted, he said.

Inside a blast furnace the size of a small airplane hanger the reactor pressure vessel was being treated one last time to remove welding stress. The cylinder, 20 meters tall and 6 meters in diameter, was heated to more than 600 degrees Celsius (1,112 degrees Fahrenheit), a temperature that softens metal.

Braces that were supposed to have been placed inside during the blasting were either forgotten or fell over when the cylinder was wheeled into the furnace. After the vessel cooled, workers found that its walls had warped, Tanaka said.
Warped Walls

The vessel had sagged so that its height and width differed by more than 34 millimeters, meaning it should have been scrapped, according to nuclear regulations. Rather than sacrifice years of work and risk the company’s survival, Tanaka’s boss asked him to reshape the vessel so that no-one would know it had ever been damaged. Tanaka had been working as an engineer for the company’s nuclear reactor division and was known for his programming skills.

“I saved the company billions of yen,” said Tanaka, who says he was paid a 3 million yen bonus and presented with a certificate acknowledging his “extraordinary” effort. “At the time, I felt like a hero,” he said.

Over the course of a month, Tanaka said he made a dozen nighttime trips to an International Business Machines Corp. office 20 kilometers away in Hiroshima where he used a super- computer to devise a repair.

Meanwhile, workers covered the damaged vessel with a sheet, Tanaka said. When Tokyo Electric sent a representative to check on their progress, Hitachi distracted him by wining and dining him, according to Tanaka. Rather than inspecting the part, they spent the day playing golf and soaking in a hot spring, he said.
Wining and Dining

“The guy wouldn’t have known what he was looking at anyway,” Tanaka said. “The people at the utility have no idea how the parts are made.”

After a month of computer modeling, Tanaka came up with a way to use pumpjacks to pop out the sunken wall. While it would look like nothing had ever happened, no-one knew what the effect of the repair would have on the integrity of the vessel. Thirty- six years later, that reactor pressure vessel is the key defense protecting the core of Fukushima’s No. 4 reactor.

“These procedures, as they’re described, are far from ideal, especially for a component as critical as this,” Robert Ritchie, Professor of Materials Science & Engineering at the University of California of Berkeley, said in a phone interview. “Depending on the extent of vessel’s deformation, it could possibly lead to local cracking in some of its welds.”
Chernobyl Breakdown

Tanaka quit Babcock-Hitachi in 1977, when he was 34 years old and became a writer. A graduate of Tokyo Institute of Technology, his Japanese-language books include “Options in Complex Systems: Natural Science and Economics on the Edge of Chaos,” and a book for young adults called, “How do we Know the Earth is Moving?”

After the meltdown at Chernobyl in 1986, Tanaka was asked to narrate a Russian movie documenting the disaster. A team of Soviet filmmakers had taken 30 hours of footage inside the plant, getting very close to the ruptured core. The movie’s director died of radiation poisoning about a year after the filming. While watching the footage, Tanaka had a breakdown.

“All of a sudden I was sobbing and I started to think about what I’d done,” Tanaka said. “I was thinking, ‘I could be the father of a Japanese Chernobyl.’”

Two years later Tanaka says he went to the Trade Ministry to report the cover-up he’d been involved in more than a decade earlier. The government refused to investigate and Hitachi denied his accusations, he said.

“They said, if Hitachi says they didn’t do it, then there’s no problem,” Tanaka said. “Companies don’t always tell the truth.”

To contact the reporter on this story: Jason Clenfield in Tokyo at jclenfield@bloomberg.net

To contact the editor responsible for this story: Peter Langan at plangan@bloomberg.net

http://www.bloomberg.com/news/2011-0...t-reactor.html

[SlowwHand]

We have not built new nuclear power plants in the United States (or started construction on new nuclear power plants) since before Three Mile Island, if I recall correctly. Dominion Power in Virginia is applying for a license to build a new reactor here but at an existing site and there is an aborted reactor site that could get restarted in Texas but other than that I don't know of any other attempts to start or revive nuclear power projects in the USA.

To reiterate, nuclear power is statistically one of the safest ways to generate electricity, but it does carry with it a minute risk of catastrophe. It's also squeaky clean with essentially zero carbon dioxide emissions and makes rivers and lakes a teensy bit warmer.

So, what's your take? Should we build nuclear power plants? Should we avoid building them near tsunami zones? Should we eschew nuclear power plants and go with natural gas? If anyone suggests hydroelectric you get punched in the ear because when dams fail it's just as bad if not worse.

Wait for the poll.

[Docfeelgood]

2-4-6-8 will will not radiate!
Hell no we wont' glow!

[Egbert]

I think it is the magnitude of the risk, not the probability that puts some people off nuclear power.

[Docfeelgood]

I think it is the magnitude of the risk, not the probability that puts some people off nuclear power.

Well said

[Bugs ****ing Bunny]

They're the same people who never have sex to avoid getting AIDS.

[Docfeelgood]

They're the same people who never have sex to avoid getting AIDS.

nil odds, very good. Masturbation is good recreation.

[Ogie Oglethorpe]

I think it is the magnitude of the risk, not the probability that puts some people off nuclear power.

I would argue event he magnitude of risk is overblown considering a comparative magnitude of risk associated with chemical industry/chemical transportation.

[Docfeelgood]

AP IMPACT: Nuclear plant downplayed tsunami risk

TOKYO – In planning their defense against a killer tsunami, the people running Japan's now-hobbled nuclear power plant dismissed important scientific evidence and all but disregarded 3,000 years of geological history, an Associated Press investigation shows.

The misplaced confidence displayed by Tokyo Electric Power Co. was prompted by a series of overly optimistic assumptions that concluded the Earth couldn't possibly release the level of fury it did two weeks ago, pushing the six-reactor Fukushima Dai-ichi complex to the brink of multiple meltdowns.

Instead of the reactors staying dry, as contemplated under the power company's worst-case scenario, the plant was overrun by a torrent of water much higher and stronger than the utility argued could occur, according to an AP analysis of records, documents and statements from researchers, the utility and the Japan's national nuclear safety agency.

And while TEPCO and government officials have said no one could have anticipated such a massive tsunami, there is ample evidence that such waves have struck the northeast coast of Japan before — and that it could happen again along the culprit fault line, which runs roughly north to south, offshore, about 220 miles (350 kilometers) east of the plant.

TEPCO officials say they had a good system for projecting tsunamis. They declined to provide more detailed explanations, saying they were focused on the ongoing nuclear crisis.

What is clear: TEPCO officials discounted important readings from a network of GPS units that showed that the two tectonic plates that create the fault were strongly "coupled," or stuck together, thus storing up extra stress along a line hundreds of miles long. The greater the distance and stickiness of such coupling, experts say, the higher the stress buildup — pressure that can be violently released in an earthquake.

That evidence, published in scientific journals starting a decade ago, represented the kind of telltale characteristics of a fault being able to produce the truly overwhelming quake — and therefore tsunami — that it did.

On top of that, TEPCO modeled the worst-case tsunami using its own computer program instead of an internationally accepted prediction method.

It matters how Japanese calculate risk. In short, they rely heavily on what has happened to figure out what might happen, even if the probability is extremely low. If the view of what has happened isn't accurate, the risk assessment can be faulty.

That approach led to TEPCO's disregard of much of Japan's tsunami history.

In postulating the maximum-sized earthquake and tsunami that the Fukushima Dai-ichi complex might face, TEPCO's engineers decided not to factor in quakes earlier than 1896. That meant the experts excluded a major quake that occurred more than 1,000 years ago — a tremor followed by a powerful tsunami that hit many of the same locations as the recent disaster.

A TEPCO reassessment presented only four months ago concluded that tsunami-driven water would push no higher than 18 feet (5.7 meters) once it hit the shore at the Fukushima Dai-ichi complex. The reactors sit up a small bluff, between 14 and 23 feet (4.3 and 6.3 meters) above TEPCO's projected high-water mark, according to a presentation at a November seismic safety conference in Japan by TEPCO civil engineer Makoto Takao.

"We assessed and confirmed the safety of the nuclear plants," Takao asserted.

However, the wall of water that thundered ashore two weeks ago reached about 27 feet (8.2 meters) above TEPCO's prediction. The flooding disabled backup power generators, located in basements or on first floors, imperiling the nuclear reactors and their nearby spent fuel pools.

___

The story leading up to the Tsunami of 2011 goes back many, many years — several millennia, in fact.

The Jogan tsunami of 869 displayed striking similarities to the events in and around the Fukushima Dai-ichi reactors. The importance of that disaster, experts told the AP, is that the most accurate planning for worst-case scenarios is to study the largest events over the longest period of time. In other words, use the most data possible.

The evidence shows that plant operators should have known of the dangers — or, if they did know, disregarded them.

As early as 2001, a group of scientists published a paper documenting the Jogan tsunami. They estimated waves of nearly 26 feet (8 meters) at Soma, about 25 miles north of the plant. North of there, they concluded that a surge from the sea swept sand more than 2 1/2 miles (4 kilometers) inland across the Sendai plain. The latest tsunami pushed water at least about 1 1/2 miles (2 kilometers) inland.

The scientists also found two additional layers of sand and concluded that two additional "gigantic tsunamis" had hit the region during the past 3,000 years, both presumably comparable to Jogan. Carbon dating couldn't pinpoint exactly when the other two hit, but the study's authors put the range of those layers of sand at between 140 B.C. and A.D. 150, and between 670 B.C. and 910 B.C.

In a 2007 paper published in the peer-reviewed journal Pure and Applied Geophysics, two TEPCO employees and three outside researchers explained their approach to assessing the tsunami threat to Japan's nuclear reactors, all 54 of which sit near the sea or ocean.

To ensure the safety of Japan's coastal power plants, they recommended that facilities be designed to withstand the highest tsunami "at the site among all historical and possible future tsunamis that can be estimated," based on local seismic characteristics.

But the authors went on to write that tsunami records before 1896 could be less reliable because of "misreading, misrecording and the low technology available for the measurement itself." The TEPCO employees and their colleagues concluded, "Records that appear unreliable should be excluded."

Two years later, in 2009, another set of researchers concluded that the Jogan tsunami had reached 1 mile (1.5 kilometers) inland at Namie, about 6 miles (10 kilometers) north of the Fukushima Dai-ichi plant.

The warning from the 2001 report about the 3,000-year history would prove to be most telling: "The recurrence interval for a large-scale tsunami is 800 to 1,100 years. More than 1,100 years have passed since the Jogan tsunami, and, given the reoccurrence interval, the possibility of a large tsunami striking the Sendai plain is high."

___

The fault involved in the Fukushima Dai-ichi tsunami is part of what is known as a subduction zone. In subduction zones, one tectonic plate dives under another. When the fault ruptures, the sea floor snaps upward, pushing up the water above it and potentially creating a tsunami. Subduction zones are common around Japan and throughout the Pacific Ocean region.

TEPCO's latest calculations were started after a magnitude-8.8 subduction zone earthquake off the coast of Chile in February 2010.

In such zones over the past 50 years, earthquakes of magnitude 9.0 or greater have occurred in Alaska, Chile and Indonesia. All produced large tsunamis.

When two plates are locked across a large area of a subduction zone, the potential for a giant earthquake increases. And those are the exact characteristics of where the most recent quake occurred.

TEPCO "absolutely should have known better," said Dr. Costas Synolakis, a leading American expert on tsunami modeling and an engineering professor at the University of Southern California. "Common sense," he said, should have produced a larger predicted maximum water level at the plant.

TEPCO's tsunami modelers did not judge that, in a worst-case scenario, the strong subduction and coupling conditions present off the coast of Fukushima Dai-ichi could produce the 9.0-magnitude earthquake that occurred. Instead, it figured the maximum at 8.6 magnitude, meaning the March 11 quake was four times as powerful as the presumed maximum.

Shogo Fukuda, a TEPCO spokesman, said that 8.6 was the maximum magnitude entered into the TEPCO internal computer modeling for Fukushima Dai-ichi.

Another TEPCO spokesman, Motoyasu Tamaki, used a new buzzword, "sotegai," or "outside our imagination," to describe what actually occurred.

U.S. tsunami experts said that one reason the estimates for Fukushima Dai-ichi were so low was the way Japan calculates risk. Because of the island nation's long history of killer waves, Japanese experts often will look at what has happened — then project forward what is likely to happen again.

Under longstanding U.S. standards that are gaining popularity around the world, risk assessments typically scheme up a worst-case scenario based on what could happen, then design a facility like a nuclear power plant to withstand such a collection of conditions — factoring in just about everything short of an extremely unlikely cataclysm, like a large meteor hitting the ocean and creating a massive wave that kills hundreds of thousands.

In the early 1990s, Harry Yeh, now a tsunami expert and engineering professor at Oregon State University, was helping assess potential threats to the Diablo Canyon nuclear power plant on the central California coast in the United States. During that exercise, he said, researchers considered a worst-case scenario involving a significantly larger earthquake than had ever been recorded there.

And then a tsunami was added. And in that Diablo Canyon model, the quake hit during a monster storm that was already pushing onto the shore higher waves than had ever been measured at the site.

In contrast, when TEPCO calculated its high-water mark at 18 feet (5.7 meters), the anticipated maximum earthquake was in the same range as others recorded off the coast of Fukushima Dai-ichi — and the only assumption about the water level was that the tsunami arrived at high tide.

Which, as is abundantly clear now, could not have been more wrong.

http://news.yahoo.com/s/ap/20110327/...e_tsunami_risk



Pure folly!