Fukushima cleanup chief urges better use of probe robot — The Seattle Times

” TOKYO (AP) — The head of decommissioning for the damaged Fukushima nuclear plant said Thursday that more creativity is needed in developing robots to locate and assess the condition of melted fuel rods.

A robot sent inside the Unit 2 containment vessel last month could not reach as close to the core area as was hoped for because it was blocked by deposits, believed to be a mixture of melted fuel and broken pieces of structures inside. Naohiro Masuda, president of Fukushima Dai-ichi Decommissioning, said he wants another probe sent in before deciding on methods to remove the reactor’s debris.

Unit 2 is one of the Fukushima reactors that melted down following the 2011 earthquake and tsunami.

The plant’s operator, Tokyo Electric Power Co., needs to know the melted fuel’s exact location as well as structural damage in each of the three wrecked reactors to figure out the best and safest ways to remove the fuel. Probes must rely on remote-controlled robots because radiation levels are too high for humans to survive.

Despite the incomplete probe missions, officials have said they want to stick to their schedule to determine the removal methods this summer and start work in 2021.

Earlier probes have suggested worse-than-anticipated challenges for the plant’s cleanup, which is expected to take decades. During the Unit 2 probe in early February, the “scorpion” robot crawler stalled after its total radiation exposure reached its limit in two hours, one-fifth of what was anticipated.

“We should think out of the box so we can examine the bottom of the core and how melted fuel debris spread out,” Masuda told reporters.

Probes are also being planned for the other two reactors. A tiny waterproof robot will be sent into Unit 1 in coming weeks, while experts are still trying to figure out a way to access the badly damaged Unit 3.

TEPCO is struggling with the plant’s decommissioning. The 2011 meltdown forced tens of thousands of nearby residents to evacuate their homes, and many have still not been able to return home due to high radiation levels.

Cleanup of communities outside of the plant is also a challenge. The cost has reportedly almost doubled to 4 trillion yen ($35 billion) from an earlier estimate. On Thursday, police arrested an Environment Ministry employee for allegedly taking bribes from a local construction firm president, media reports said. ”

by Mari Yamaguchi, The Associated Press

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The Fukushima nuclear meltdown continues unabated — Helen Caldicott, Independent Australia

Helen Caldicott sums up the situation here:

” Recent reporting of a huge radiation measurement at Unit 2 in the Fukushima Daichi reactor complex does not signify that there is a peak in radiation in the reactor building.

All that it indicates is that, for the first time, the Japanese have been able to measure the intense radiation given off by the molten fuel, as each previous attempt has led to failure because the radiation is so intense the robotic parts were functionally destroyed.

The radiation measurement was 530 sieverts, or 53,000 rems (Roentgen Equivalent for Man). The dose at which half an exposed population would die is 250 to 500 rems, so this is a massive measurement. It is quite likely had the robot been able to penetrate deeper into the inner cavern containing the molten corium, the measurement would have been much greater.

These facts illustrate why it will be almost impossible to “decommission” units 1, 2 and 3 as no human could ever be exposed to such extreme radiation. This fact means that Fukushima Daichi will remain a diabolical blot upon Japan and the world for the rest of time, sitting as it does on active earthquake zones.

What the photos taken by the robot did reveal was that some of the structural supports of Unit 2 have been damaged. It is also true that all four buildings were structurally damaged by the original earthquake some five years ago and by the subsequent hydrogen explosions so, should there be an earthquake greater than seven on the Richter scale, it is very possible that one or more of these structures could collapse, leading to a massive release of radiation as the building fell on the molten core beneath. But units 1, 2 and 3 also contain cooling pools with very radioactive fuel rods — numbering 392 in Unit 1, 615 in Unit 2, and 566 in Unit 3; if an earthquake were to breach a pool, the gamma rays would be so intense that the site would have to be permanently evacuated. The fuel from Unit 4 and its cooling pool has been removed.

But there is more to fear.

The reactor complex was built adjacent to a mountain range and millions of gallons of water emanate from the mountains daily beneath the reactor complex, causing some of the earth below the reactor buildings to partially liquefy. As the water flows beneath the damaged reactors, it immerses the three molten cores and becomes extremely radioactive as it continues its journey into the adjacent Pacific Ocean.

Every day since the accident began, 300 to 400 tons of water has poured into the Pacific where numerous isotopes – including cesium 137, 134, strontium 90, tritium, plutonium, americium and up to 100 more – enter the ocean and bio-concentrate by orders of magnitude at each step of the food chain — algae, crustaceans, little fish, big fish then us.

Fish swim thousands of miles and tuna, salmon and other species found on the American west coast now contain some of these radioactive elements, which are tasteless, odourless and invisible. Entering the human body by ingestion they concentrate in various organs, irradiating adjacent cells for many years. The cancer cycle is initiated by a single mutation in a single regulatory gene in a single cell and the incubation time for cancer is any time from 2 to 90 years. And no cancer defines its origin.

We could be catching radioactive fish in Australia or the fish that are imported could contain radioactive isotopes, but unless they are consistently tested we will never know.

As well as the mountain water reaching the Pacific Ocean, since the accident, TEPCO has daily pumped over 300 tons of sea water into the damaged reactors to keep them cool. It becomes intensely radioactive and is pumped out again and stored in over 1,200 huge storage tanks scattered over the Daichi site. These tanks could not withstand a large earthquake and could rupture releasing their contents into the ocean.

But even if that does not happen, TEPCO is rapidly running out of storage space and is trying to convince the local fishermen that it would be okay to empty the tanks into the sea. The Bremsstrahlung radiation like x-rays given off by these tanks is quite high – measuring 10 milirems – presenting a danger to the workers. There are over 4,000 workers on site each day, many recruited by the Yakuza (the Japanese Mafia) and include men who are homeless, drug addicts and those who are mentally unstable.

There’s another problem. Because the molten cores are continuously generating hydrogen, which is explosive, TEPCO has been pumping nitrogen into the reactors to dilute the hydrogen dangers.

Vast areas of Japan are now contaminated, including some areas of Tokyo, which are so radioactive that roadside soil measuring 7,000 becquerels (bc) per kilo would qualify to be buried in a radioactive waste facility in the U.S..

As previously explained, these radioactive elements concentrate in the food chain. The Fukushima Prefecture has always been a food bowl for Japan and, although much of the rice, vegetables and fruit now grown here is radioactive, there is a big push to sell this food both in the Japanese market and overseas. Taiwan has banned the sale of Japanese food, but Australia and the U.S. have not.

Prime Minister Abe recently passed a law that any reporter who told the truth about the situation could be [jail]ed for ten years. In addition, doctors who tell their patients their disease could be radiation related will not be paid, so there is an immense cover-up in Japan as well as the global media.

The Prefectural Oversite Committee for Fukushima Health is only looking at thyroid cancer among the population and by June 2016, 172 people who were under the age of 18 at the time of the accident have developed, or have suspected, thyroid cancer; the normal incidence in this population is 1 to 2 per million.

However, other cancers and leukemia that are caused by radiation are not being routinely documented, nor are congenital malformations, which were, and are, still rife among the exposed Chernobyl population.

Bottom line, these reactors will never be cleaned up nor decommissioned because such a task is not humanly possible. Hence, they will continue to pour water into the Pacific for the rest of time and threaten Japan and the northern hemisphere with massive releases of radiation should there be another large earthquake. ”

by Helen Caldicott

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Fukushima frozen wall status 2017; Unit 3 cover building installation — SimplyInfo.org

SimlyInfo.org shows a map of the current status of the frozen ice wall at Fukushima No. 1.

* * *

Read SimplyInfo.org’s article on the current construction of a cover building for Fukushima Daiichi’s Unit 3, which will hopefully allow for robotic removal of spent fuel.

 

Fukushima clean-up chief still hunting for 600 tonnes of melted radioactive fuel — Mark Willacy, ABC

” The operator of the stricken Fukushima nuclear plant has revealed that 600 tonnes of reactor fuel melted during the disaster, and that the exact location of the highly radioactive blobs remains a mystery.

 In an exclusive interview with Foreign Correspondent, the Tokyo Electric Power Company’s chief of decommissioning at Fukushima, Naohiro Masuda, said the company hoped to pinpoint the position of the fuel and begin removing it from 2021.

But he admitted the technology needed to remove the fuel has to be invented.

“Once we can find out the condition of the melted fuel and identify its location, I believe we can develop the necessary tools to retrieve it,” Mr Masuda said.

“So it’s important to find it as soon as possible.”

Clean-up to take decades, cost tens of billions of dollars

Reactors 1, 2 and 3 at the Fukushima Dai-ichi nuclear plant suffered catastrophic meltdowns in the hours and days after a giant tsunami swamped the facility on 11 March, 2011.

Thousands of workers are braving elevated radiation levels to stabilise and decommission the plant.

TEPCO says the process will take 30 to 40 years and tens of billions of dollars.

“In Reactor 1, all of the fuel has melted down from inside the pressure vessel,” Mr Masuda said.

“In reactors 2 and 3, about 30 per cent to 50 per cent remains in the pressure vessel and the rest has melted down. But unfortunately, we don’t know exactly where [the fuel] is.”

The head of the United States Nuclear Regulatory Commission (NRC) at the time of the meltdowns at Fukushima doubts the fuel can be retrieved, saying such an operation has never been done before.

“Nobody really knows where the fuel is at this point and this fuel is still very radioactive and will be for a long time,” said Gregory Jaczko in an interview with Foreign Correspondent in Washington.

“It may be possible that we’re never able to remove the fuel. You may just have to wind up leaving it there and somehow entomb it as it is.”

Radiation killing search robots inside reactor

For the first time, TEPCO has revealed just how much of the mostly uranium fuel melted down after the tsunami swamped the plant.

“It’s estimated that approximately 200 tonnes of debris lies within each unit,” said TEPCO’s Naohiro Masuda.

“So in total, about 600 tonnes of melted debris fuel and a mixture of concrete and other metals are likely to be there.”

TEPCO has attempted to use custom-built robots to access high-dose radiation parts of the reactor buildings where humans cannot go.

“All the robots have been disabled, the instrumentation, the camera … have been disabled because of the high radiation fields,” former NRC boss Gregory Jaczko said.

Appointed to head the US nuclear watchdog by President Barack Obama in 2009, Dr Jaczko resigned a year after the Fukushima disaster.

A particle physicist, he now questions the safety of nuclear power.

“You have to now accept that in all nuclear power plants, wherever they are in the world … that you can have this kind of a very catastrophic accident and you can release a significant amount of radiation and have a decade long clean-up effort on your hands,” he said.

10 million bags of contaminated soil in gigantic waste dumps

Another supporter turned opponent of nuclear power is Naoto Kan, who was the Japanese prime minister at the time of the Fukushima meltdowns.

He says those who argue that nuclear power is a safe, cheap source of energy are misguided.

“So far, the government is paying $70 billion to support TEPCO,” Mr Kan said.

“But that is not enough. It will probably cost more than $240 billion. I think 40 years [to decommission the plant] is an optimistic view.”

More than 100,000 Japanese are still unable to return home because their communities lie in elevated radiation zones.

Some people have returned to their towns and villages since the completion of decontamination work, which often involves the removal of up to 15 centimetres of topsoil from fields and from around homes.

More than 10 million large bags of contaminated soil and waste have so far been collected. The bags are now stored in thousands of sites around Fukushima, with some of the piles several storeys high.

“In order for people to come back, we need to show that the Fukushima plant is in a stable condition,” Naohiro Masuda said.

“We need to make that the situation … we’re working on something [for] which there is no textbook.” ”

by Mark Willacy

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Manga artist and ex-Fukushima No. 1 worker portrays life, progress at troubled plant — The Japan Times

” A manga artist who has been involved in decommissioning work at the disaster-hit Fukushima No. 1 nuclear plant has highlighted the need for effective deployment of skilled workers in parts of the premises that still have high radiation levels.

Kazuto Tatsuta, 51, also said in a recent interview that he feels progress has been made since the Tokyo Electric Power Co. complex suffered triple meltdowns after the March 11, 2011 quake and tsunami disaster in an operation that will take decades.

“It is not hard to collect a large number of ordinary workers, but lower wages resulting from multilayered (subcontractors) is a problem that could, in severely bad cases, have an impact on their motivation,” Tatsuta said, noting that about 7,000 people work at the plant every day.

Tatsuta, who uses a pen name for fear of being prevented from working at the plant again, commuted to the complex intermittently between June 2012 and November 2014 to engage in such work as managing rest stations for other workers, plumbing within the reactor 3 building and taking care of robots operating within the units.

His manga stories “Ichiefu” (“1F”), published by Kodansha Ltd., portray the ordinary lives and attitudes of workers at the complex. For example, they were irritated by itchy noses as a result of wearing full face masks and were more afraid of the heat in summer than of radiation.

Ichiefu is an abbreviation for the Fukushima No. 1 nuclear plant commonly used among local people and those related to the industry.

Tatsuta, who has frequently changed jobs since graduating from university, said work at the Fukushima plant is by no means lucrative. “Initially, I didn’t aim to work in 1F. After seeking a job in disaster-hit areas including Miyagi or Iwate, I just found one at the nuclear plant.”

But he said, “The construction company I worked for was a sixth subcontractor (of Tepco) and the salary was no different from that for ordinary work. My dream of making a lot of money in a short period was (dashed).”

His pay started at ¥8,000 (about $70) a day working in the rest houses, and rose to ¥20,000 per day for work within the reactor buildings.

His three-volume book series depicts workers from all across Japan having to bear their own living costs in uncomfortable lodgings before work is officially allocated, or not receiving any pay when accidents or other problems cause operations at the plant to be abruptly suspended.

Tatsuta also noted the need for experts, in addition to ordinary workers. “In order to get experts who have experience and skills relating to nuclear plants to work as long as possible, the management of radiation is crucial,” he said. “The longer these workers are exposed to radiation, the shorter they are able to stay in higher dose places.”

Measures against radiation, including decontamination of such areas and the setting up of protective barriers around them, are essential, he said.

Ahead of the fifth anniversary of the nuclear crisis, many media outlets were allowed to enter the premises to report on the current situation at the plant.

“A big development is that workers are able to move around (wide ares of the) premises without full face masks,” said Tatsuta, having seen photos in a newspaper. Currently, people can work with masks that cover only half their face in about 90 percent of the premises, except for areas around the stricken reactors.

The media tend to report that reconstruction of the disaster-hit area is still only halfway done. But Tatsuta called on readers to focus on the things that are progressing, albeit little by little.

Within the Fukushima complex, the completion of a frozen underground wall to prevent radioactive water from accumulating further and the piling up of around 1,000 tanks to store processed contaminated water are indications of the significant progress made since Tatsuta left 1F, he said, though admitting there was still considerable work to be done.

“Ichiefu” features ordinary middle-aged men who take naps while waiting for their colleagues to finish their jobs, chat cheerfully with their co-workers or play pachinko in their free time.

“Some people viewed us as heroes, saying ‘Thank you very much on behalf of Japan and the world.’ Others felt very sorry for us, saying ‘You were treated like slaves in dangerous working conditions.’ But I want to say that neither of these views is correct. I’d like readers to understand that to some extent.

“As one of those workers, I wanted to describe the gap between what the public thought and what I saw inside. ‘Ichiefu’ is . . . like my diary, but I am pleased if it has resulted in showing the workers’ real lives.”

Tatsuta, who describes himself as a cartoonist who doesn’t sell well, was careful not to indicate his own political views on the government’s nuclear policies for fear that this would make his work seem biased.

“I neither agree nor disagree with the restart of nuclear plants, although I am frequently asked that question,” he said.

Having made its debut in a weekly magazine in October 2013, some 350,000 copies of “Ichiefu” have now been printed in Japan. It has also hit the shelves in Taiwan, with French, Spanish, German and Italian versions being published soon.

Tatsuta now calls Fukushima his “second hometown” as a result of the connections he made while living and working there, and said, “I hope to work there for the rest of my life, if possible.”

But he has had no chance to work at the complex since December 2014, and sometimes suspects that because Tepco or one of its subcontractors has discovered his identity as the author of the manga series, he is unable to return there.

“It can’t be helped. I have been prepared for that from the beginning,” he said. “But once I became involved (in 1F), I began looking forward and I am closely observing how it will be cleaned up. It can’t turn any worse from now.”

Tatsuta is currently working on a manga story for an upcoming book on the decommissioning of the Fukushima plant co-authored by Hiroshi Kainuma, a Fukushima-born sociologist. ”

by Satoshi Iizuka

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Five years after the meltdown, is it safe to live near Fukushima? — Science

” A  long, grinding struggle back to normal is underway at the Fukushima Daiichi Nuclear Power Plant in Japan. As workers make progress in cleaning up contaminated land surrounding its infamous reactor, evacuees are grappling with whether to return to homes sealed off since the accident there 5 years ago. The power plant itself remains a dangerous disaster zone, with workers just beginning the complex, risky job of locating the melted fuel and figuring out how to remove it.

The magnitude 9.0 earthquake that struck northeastern Japan on 11 March 2011 and the 40-meter tsunami that followed left 15,893 dead and 2572 missing, destroyed 127,290 buildings, and damaged more than a million more. It also triggered the meltdowns at Fukushima and the evacuation of 150,000 people from within 20 kilometers of the nuclear plant as well as from areas beyond that were hard hit by fallout.

Now, the nuclear refugees face a dilemma: How much radiation in their former homes is safe? In a herculean effort, authorities have so far scooped up some 9 million cubic meters of contaminated soil and leaves and washed down buildings and roadways with the goal of reducing outdoor radiation exposure to 0.23 microsieverts per hour. Last September, the government began lifting evacuation orders for the seven municipalities wholly or partly within 20 kilometers of the plant. As the work progresses, authorities expect that 70% of the evacuees will be allowed to return home by spring 2017.

But evacuees are torn over safety and compensation issues. Many claim they are being compelled to go home, even though radiation exposure levels, they feel, are still too high. “There has been no education regarding radiation,” says Katsunobu Sakurai, the mayor of Minamisoma, where 14,000 people were evacuated after the accident. “It’s difficult for many people to make the decision to return without knowing what these radiation levels mean and what is safe,” he says. Some citizen groups are suing the national government and Tokyo Electric Power Company (TEPCO), the Fukushima plant’s owner, over plans to end compensation payments for those who choose not to return home. Highly contaminated areas close to the nuclear plant will remain off limits indefinitely.

Conditions at the plant are “really stable,” the plant manager, Akira Ono, recently told reporters. Radioactivity and heat from the nuclear fuel have fallen substantially in the past 5 years, he says. But cleanup is off to a slow start, hampered by sketchy knowledge of where the nuclear fuel is located. Last year managers agreed to a road map for decommissioning the site over the next 30 to 40 years that calls for removing melted nuclear fuel masses and demolishing the plant’s four reactor halls at a cost that could top $9 billion. TEPCO intends to start removing nuclear debris from the reactors in 2021.

Ono puts the decommissioning at “around 10%” complete. One big hurdle was cleared in December 2014, when crews removed the last of 1535 fuel rods stored in the Unit 4 spent fuel pool. At the time of the accident, some feared that cooling water had drained out of the pool and exposed the fuel to air, which might have led to overheating and melting. It hadn’t, but the fuel remained a threat.

The biggest challenge at present, Ono says, is contaminated water. Cooling water is continuously poured over the melted cores of units 1, 2, and 3 to keep the fuel from overheating and melting again. The water drains into building basements, where it mixes with groundwater. To reduce the amount of contaminated water seeping into the ocean, TEPCO collects and stores it in 10-meter-tall steel tanks. They now fill nearly every corner of the grounds, holding some 750,000 tons of water. The government is evaluating experimental techniques for cleansing the water of a key radioisotope, tritium. Ono says a solution is sorely needed before the plant runs out of room for more tanks.

TEPCO has found ways to divert groundwater from the site, cutting infiltration to about 150 tons per day. Now it’s about to freeze out the rest. Borrowing a technique for making temporary subsurface barriers during tunnel construction, a contractor has driven 1500 pipes 30 meters down to bedrock, creating something akin to an underground picket fence encircling the four crippled reactor units. Brine chilled to –30°C circulating in the pipes will freeze the soil between the pipes; the frozen wall should keep groundwater out and contaminated water in. TEPCO was planning to start the operation shortly after Science went to press.

The most daunting task is recovering the fuel debris. TEPCO modeling and analyses suggest that most, if not all, of the fuel in the Unit 1 reactor melted, burned through the reactor pressure vessel, dropped to the bottom of the containment vessel, and perhaps ate into the concrete base. Units 2 and 3 suffered partial meltdowns, and some fuel may remain in the cores.

To try to confirm the location and condition of the melted fuel, the International Research Institute for Nuclear Decommissioning, set up by TEPCO and other entities, has been probing the reactors’ innards with muons. Wispy cousins of the electron, muons are generated by the trillions each minute when cosmic rays slam into the upper atmosphere. A few muons are absorbed or scattered, at a rate that depends on a material’s density. Because uranium is denser than steel or concrete, muon imaging can potentially locate the fuel debris.

In February 2015, a group at Japan’s High Energy Accelerator Research Organization in Tsukuba supplied two van-sized muon detectors, which TEPCO placed adjacent to the Unit 1 reactor at ground level. After a month of collecting muons, the detectors confirmed there was no fuel left in the core. Because they were positioned at ground level, the devices could not image the reactor building basements and so could not pin down where the fuel is or its condition. TEPCO plans to use robots to map the location of the fuel debris so it can develop a strategy for removing it (see story, right).

A second team has developed detectors that observe muons before and after they pass through an object of interest, promising a more precise picture of reactor interiors. For Fukushima, the researchers—from Los Alamos National Laboratory in New Mexico and Japan’s Toshiba Corp.—built mammoth detectors, 7 meters across, which they intended to place outside Unit 2. That work has been postponed because TEPCO decided to first send a robot into the containment vessel; high radiation levels have delayed that plan. “Our current task is to reduce that exposure,” Ono says, using robotic floor and wall scrubbers in the area workers need to access to deploy the robot.

While the authorities struggle to clean up the site and resettle residents, some locals are judging safety for themselves. In 2014, a group of enterprising high school students in Fukushima city, outside the evacuation zone, launched an international radiation-dosimetry project. Some 216 students and teachers at six schools in Fukushima Prefecture, six elsewhere in Japan, four in France, eight in Poland, and two in Belarus wore dosimeters for 2 weeks while keeping detailed diaries of their whereabouts and activities. “I wanted to know how high my exposure dose was and I wanted to compare that dose with people living in other places,” explains Haruka Onodera, a member of Fukushima High School’s Super Science Club, which conceived the project. The students published their findings last November in the Journal of Radiological Protection. Their conclusion: “High school students in Fukushima [Prefecture] do not suffer from significantly higher levels of radiation” than those living elsewhere, Onodera says.

That’s good news for Fukushima city residents, perhaps, but cold comfort to displaced people now weighing the prospect of moving back to homes closer to the shattered nuclear plant. ”

by Dennis Normile

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