Thirty-five years ago, Dale G. Bridenbaugh and two of his colleagues at General Electric resigned from their jobs after becoming increasingly convinced that the nuclear reactor design they were reviewing -- the Mark 1 -- was so flawed it could lead to a devastating accident.
Questions persisted for decades about the ability of the Mark 1 to handle the immense pressures that would result if the reactor lost cooling power, and today that design is being put to the ultimate test in Japan. Five of the six reactors at the Fukushima Daiichi plant, which has been wracked since Friday's earthquake with explosions and radiation leaks, are Mark 1s.
"The problems we identified in 1975 were that, in doing the design of the containment, they did not take into account the dynamic loads that could be experienced with a loss of coolant," Bridenbaugh told ABC News in an interview. "The impact loads the containment would receive by this very rapid release of energy could tear the containment apart and create an uncontrolled release."
The situation on the ground at the Fukushima Daiichi plant is so fluid, and the details of what is unfolding are so murky, that it may be days or even weeks before anyone knows how the Mark 1 containment system performed in the face of a devastating combination of natural disasters.
But the ability of the containment to withstand the events that have cascaded from what nuclear experts call a "station blackout" -- where the loss of power has crippled the reactor's cooling system -- will be a crucial question as policy makers re-examine the safety issues that surround nuclear power, and specifically the continued use of what is now one of the oldest types of nuclear reactors still operating.
GE told ABC News the reactors have "a proven track record of performing reliably and safely for more than 40 years" and "performed as designed," even after the shock of a 9.0 earthquake.
Still, concerns about the Mark 1 design have resurfaced occasionally in the years since Bridenbaugh came forward. In 1986, for instance, Harold Denton, then the director of NRC's Office of Nuclear Reactor Regulation, spoke critically about the design during an industry conference.
"I don't have the same warm feeling about GE containment that I do about the larger dry containments,'' he said, according to a report at the time that was referenced Tuesday in The Washington Post.
"There is a wide spectrum of ability to cope with severe accidents at GE plants,'' Denton said. "And I urge you to think seriously about the ability to cope with such an event if it occurred at your plant.''
Experts Had Long Criticized Potential Weakness in Design of Stricken ReactorBy TOM ZELLER Jr.
Published: March 15, 2011
The warnings were stark and issued repeatedly as far back as 1972: If the cooling systems ever failed at a “Mark 1” nuclear reactor, the primary containment vessel surrounding the reactor would probably burst as the fuel rods inside overheated. Dangerous radiation would spew into the environment.
Now, with one Mark 1 containment vessel damaged at the embattled Fukushima Daiichi nuclear plant and other vessels there under severe strain, the weaknesses of the design — developed in the 1960s by General Electric — could be contributing to the unfolding catastrophe.
When the ability to cool a reactor is compromised, the containment vessel is the last line of defense. Typically made of steel and concrete, it is designed to prevent — for a time — melting fuel rods from spewing radiation into the environment if cooling efforts completely fail.
In some reactors, known as pressurized water reactors, the system is sealed inside a thick steel-and-cement tomb. Most nuclear reactors around the world are of this type.
But the type of containment vessel and pressure suppression system used in the failing reactors at Japan’s Fukushima Daiichi plant is physically less robust, and it has long been thought to be more susceptible to failure in an emergency than competing designs. In the United States, 23 reactors at 16 locations use the Mark 1 design, including the Oyster Creek plant in central New Jersey, the Dresden plant near Chicago and the Monticello plant near Minneapolis.
G.E. began making the Mark 1 boiling-water reactors in the 1960s, marketing them as cheaper and easier to build — in part because they used a comparatively smaller and less expensive containment structure.
American regulators began identifying weaknesses very early on.
In 1972, Stephen H. Hanauer, then a safety official with the Atomic Energy Commission, recommended that the Mark 1 system be discontinued because it presented unacceptable safety risks. Among the concerns cited was the smaller containment design, which was more susceptible to explosion and rupture from a buildup in hydrogen — a situation that may have unfolded at the Fukushima Daiichi plant. Later that same year, Joseph Hendrie, who would later become chairman of the Nuclear Regulatory Commission, a successor agency to the atomic commission, said the idea of a ban on such systems was attractive. But the technology had been so widely accepted by the industry and regulatory officials, he said, that “reversal of this hallowed policy, particularly at this time, could well be the end of nuclear power.”
In an e-mail on Tuesday, David Lochbaum, director of the Nuclear Safety Program at the Union for Concerned Scientists, said those words seemed ironic now, given the potential global ripples from the Japanese accident.
“Not banning them might be the end of nuclear power,” said Mr. Lochbaum, a nuclear engineer who spent 17 years working in nuclear facilities, including three that used the G.E. design.
Questions about the design escalated in the mid-1980s, when Harold Denton, an official with the Nuclear Regulatory Commission, asserted that Mark 1 reactors had a 90 percent probability of bursting should the fuel rods overheat and melt in an accident.
Industry officials disputed that assessment, saying the chance of failure was only about 10 percent.
Michael Tetuan, a spokesman for G.E.’s water and power division, staunchly defended the technology this week, calling it “the industry’s workhorse with a proven track record of safety and reliability for more than 40 years.”
Mr. Tetuan said there are currently 32 Mark 1 boiling-water reactors operating safely around the globe. “There has never been a breach of a Mark 1 containment system,” he said.
Several utilities and plant operators also threatened to sue G.E. in the late 1980s after the disclosure of internal company documents dating back to 1975 that suggested that the containment vessel designs were either insufficiently tested or had flaws that could compromise safety.
Continued... Explosion and Fire at Fourth Japanese Nuclear Reactor ... Government Says High Levels of Radiation Being ReleasedKyodo News noted earlier that Reactor Number 4 has caught fire:
The Herald Sun reported:
RADIATION levels near a quake-stricken nuclear plant are now harmful to human health, Japan's government says after explosions and a fire at the facility.
"There is no doubt that unlike in the past, the figures are the level at which human health can be affected," said chief government spokesman Yukio Edano.
***
Although the number-four reactor was shut for maintenance when the quake and tsunami struck last Friday, "spent nuclear fuel in the reactor heated up, creating hydrogen and triggered a hydrogen explosion".
He said radioactive substances were leaked along with the hydrogen.
"Please keep in mind that what is burning is not nuclear fuel itself," Mr Edano said. "We'll do our best to put out or control the fire as soon as possible."
AP now says the fire has now been put out, although the Japanese government says that high levels of radiation are being released:
Prime Minister Naoto Kan said radiation has spread from four reactors of the Fukushima Dai-ichi nuclear plant in Fukushima province, one of the hardest-hit in Friday's 9.0-magnitude earthquake and the ensuing tsunami that has killed more than 10,000 people. "The level seems very high, and there is still a very high risk of more radiation coming out,"
***
The fire was put out. Even though it was unoperational, the fourth reactor was believed to be the source of the elevated radiation release because of the hydrogen release that triggered the fire.
***
"It is likely that the level of radiation increased sharply due to a fire at Unit 4," Edano said. "Now we are talking about levels that can damage human health.
Hopefully, Edano is right, and the high levels of radiation were due to a temporary fire, which has been put out.
However, high radiation levels were reported before the fire, when reactor number 2 exploded earlier today, and the government said that its containment core had been breached.
More:
http://www.washingtonsblog.com/2011/03/fire-at-reactor-number-4.html
Third blast hits nuclear plant as it's confirmed radiation 'has been released into the atmosphere'Read more:
http://www.dailymail.co.uk/news/article-1366308/Japan-earthquake-tsunami-Race-avoid-meltdown-blast-rocks-nuclear-plant.html#ixzz1GeicS5qb# Radiation 'has been released into the atmosphere at damaged nuclear plant'
# Explosion at Number 2 reactor follows destruction of 1 and 3
# Fire breaks out at Number 4
# Fears for residents yet to make it outside 19-mile exclusion zone
# Radioactive wind could reach Tokyo today
# Stock markets in chaos as Nikkei plummets 10.5% in one day
Radiation fears after Japan blastRadiation from Japan's quake-stricken Fukushima Daiichi nuclear plant has reached harmful levels, the government says.The warning comes after the plant was rocked by a third blast which appears to have damaged one of the reactors' containment vessels for the first time.
If it is breached, there are fears of more serious radioactive leaks.
Officials have extended the danger zone, warning residents within 30km (18 miles) to evacuate or stay indoors.
The crisis was sparked by a 9.0-magnitude quake and tsunami on Friday.
'Don't go outside'On Tuesday morning, reactor 2 became the
third to explode in four days at the Fukushima Daiichi plant - 250km (155 miles) north-east of Tokyo.
A fire also briefly broke out at the plant's reactor 4 on Tuesday and is believed to have led to radioactive leaks.
READ MORETOKYO (Reuters) - Workers were ordered to withdraw briefly from a stricken Japanese nuclear power plant on Wednesday after radiation levels surged, Kyodo news reported, a development that suggested the crisis was spiralling out of control.
Just hours earlier another fire broke out at the earthquake-crippled plant, which has sent low levels of radiation wafting into Tokyo in the past 24 hours, triggering both fear in the capital and international alarm.
The workers were allowed back into the plant after almost an hour when the radiation levels had fallen.
Japan's chief government spokesman said it was "not realistic" to think the Daiichi nuclear plant in Fukushima, 240 kms (150 miles) north of Tokyo, would reach the start of a nuclear chain reaction, but said officials were talking to the U.S. military about possible help.
While public broadcaster NHK said flames were no longer visible at the building housing the No.4 reactor of the plant, TV pictures showed smoke or steam rising from the facility around 1 a.m. British time.
Academics and nuclear experts agree that the solutions being proposed to contain damage to the reactors are last-ditch efforts to stem what could well be remembered as one of the world's worst industrial disasters.
"This is a slow-moving nightmare," said Dr Thomas Neff, a research affiliate at the Centre for International Studies, which is part of the Massachusetts Institute of Technology.
Concern had earlier been mounting that the skeleton crews dealing with the crisis might not be big enough, or were possibly exhausted after working for days since last Friday's massive earthquake damaged the facility. Authorities had withdrawn 750 workers on Tuesday, leaving only 50.
The plight of hundreds of thousands left homeless by the quake and devastating tsunami that followed worsened overnight following a cold snap that brought snow to some of the worst-affected areas.
While the official death toll stands at around 4,000, more than 7,000 are listed as missing and the figure is expected to rise.
In the first hint of international frustration at the pace of updates from Japan, Yukiya Amano, director general of the International Atomic Energy Agency, said he wanted more timely and detailed information.
"We do not have all the details of the information so what we can do is limited," Amano told a news conference in Vienna. "I am trying to further improve the communication."
Several experts said that Japanese authorities were underplaying the severity of the incident, particularly on a scale called INES used to rank nuclear incidents. The Japanese have so far rated the accident a four on a one-to-seven scale, but that rating was issued on Saturday and since then the situation has worsened dramatically.
France's nuclear safety authority ASN said Tuesday it should be classed as a level-six incident.
Japanese Prime Minister Naoto Kan on Tuesday urged people within 30 km (18 miles) of the facility -- a population of 140,000 -- to remain indoors, as authorities grappled with the world's most serious nuclear accident since the Chernobyl disaster in Ukraine in 1986.
Officials in Tokyo said radiation in the capital was 10 times normal at one point but not a threat to human health in the sprawling high-tech city of 13 million people.
But residents have nevertheless reacted to the crisis by staying indoors. Public transport and the streets are as deserted as they would be on a public holiday, and many shops and offices are closed.
Winds over the plant will blow from the north along the Pacific coast early on Wednesday and then from the northwest towards the ocean during the day, the Japan Meteorological Agency said.
Fears of trans-Pacific nuclear fallout sent consumers scrambling for radiation antidotes in the U.S. Pacific Northwest and Canada. Authorities warned that people would expose themselves to other medical problems by needlessly taking potassium iodide in the hope of protection from cancer.
The nuclear crisis and concerns about the economic impact from the quake and tsunami have hammered Japan's stock market.
The Nikkei index ended the morning up 4.37 pct after closing down 10.6 percent on Tuesday and 6.2 percent the day before. The fall wiped some $620 billion (386 billion pounds) off the market.
SCRAMBLE TO STOP WATER EVAPORATING
Authorities have spent days desperately trying to prevent the water which is designed to cool the radioactive cores of the reactors from evaporating, which would lead to overheating and the release of dangerous radioactive material into the atmosphere.
Levels of 400 millisieverts per hour had been recorded near the No. 4 reactor, the government said. Exposure to over 100 millisieverts a year is a level which can lead to cancer, according to the World Nuclear Association.
Several embassies advised staff and citizens to leave affected areas in Japan. Tourists cut short vacations and multinational companies either urged staff to leave or said they were considering plans to move outside Tokyo.
German technology companies SAP and Infineon were among those moving staff to safety in the south. SAP said it was evacuating its offices in Tokyo, Osaka and Nagoya and had offered its 1,100 employees and their family members transport to the south, where the company has rented a hotel for staff to work online.
"WHAT THE HELL IS GOING ON?"
Japanese media have became more critical of Kan's handling of the disaster and criticised the government and plant operator Tokyo Electric Power Co. for their failure to provide enough information on the incident.
Kan himself lambasted the operator for taking so long to inform his office about one of the blasts on Tuesday, Kyodo news agency reported.
Kyodo said Kan had ordered TEPCO not to pull employees out of the plant. "The TV reported an explosion. But nothing was said to the premier's office for about an hour," a Kyodo reporter quoted Kan telling power company executives. "What the hell is going on?"
Nuclear radiation is an especially sensitive issue for Japanese following the country's worst human catastrophe -- the U.S. atomic bombs dropped on Hiroshima and Nagasaki in 1945.
There have been a total of four explosions at the plant since it was damaged in last Friday's massive quake and tsunami. The most recent were blasts at reactors Nos. 2 and 4.
Concern now centres on damage to a part of the No.4 reactor building where spent rods were being stored in pools of water outside the containment area, and also to part of the No.2 reactor that helps to cool and trap the majority of cesium, iodine and strontium in its water.
VILLAGES AND TOWNS WIPED OFF THE MAP
The full extent of the destruction from last Friday's 9.0-magnitude earthquake and the tsunami that followed it was becoming clear as rescuers combed through the region north of Tokyo where officials say at least 10,000 people were killed.
Whole villages and towns have been wiped off the map by Friday's wall of water, triggering an international humanitarian effort of epic proportions.
There have been hundreds of aftershocks and more than two dozen are greater than magnitude 6, the size of the earthquake that severely damaged Christchurch, New Zealand last month.
About 850,000 households in the north were still without electricity in near-freezing weather, Tohuku Electric Power Co. said, and the government said at least 1.5 million households lack running water. Tens of thousands of people were missing.
Hiromichi Shirakawa, chief economist for Japan at Credit Suisse, said in a note to clients that the economic loss will likely be around 14-15 trillion yen (106-114 billion pounds) just to the region hit by the quake and tsunami.
"The earthquake could have great implications on the global economic front," said Andre Bakhos, director of market analytics at Lec Securities in New York.
"If you shut down Japan, there could be a global recession."http://www.swissinfo.ch/eng/news/international/Radiation_leaps_after_Japan_plant_blasts,_warnings_for_Tokyo.html?cid=29698946 
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