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The News That Matters about the Nuclear Industry

The Robot Probe Cannot Confirm Where is the Melted Fuel of Unit 1

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Tokyo Electric Power Company announced on February 23 that it had completed a robot probe survey lasting five days in the reactor containment vessel of Fukushima Daiichi nuclear power plant Unit 1.

Its goal was to confirm the whereabout of the melted nuclear fuel, but it was blocked by piping and could not put the camera in athe place where nuclear fuel could be seen.

Information necessary for taking out the nuclear fuel to decommission the reactor remains inadequate, and some voices began to question the robot conducted investigation method.

During the 5-day survey, there was also a point where the measuring instrument with an camera and a radiation dosimeter integrated together was hung up in a range from 0 to 3 meters from the bottom of the containment vessel, pipes and debris blocking its path in many points. The radiation dose in the water is from 3.0 to 11 Sv. Per hour. It was not possible to directly check the melted nuclear fuel.

TEPCO and the country are facing the decommissioning of a furnace …

http://www.asahi.com/articles/photo/AS20170323005483.html

March 24, 2017 Posted by | Fukushima 2017 | , , , , | Leave a comment

Deadly nuclear radiation levels detected in Fukushima

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Extremely high radiation levels were detected using cameras and robots in tainted water inside a reactor containment vessel at the Fukushima No. 1 nuclear power plant, Japan Times reported Tuesday, citing Tokyo Electric Power Company Holdings Inc. (Tepco).

The latest readings, taken six years after the Fukushima nuclear meltdown, showed 11 sieverts per hour, according to Japan Times. It is the highest radiation level detected in water inside the containment vessel and is extremely dangerous. Sievert is a unit measurement for a dose of radiation. One sievert is enough to cause illness if absorbed all at once, and 8 sieverts will result in death despite treatment, according to PBS who relied on data from multiple sources including United States Nuclear Regulatory Commission and MIT’s Nuclear Science and Engineering department.

Following a major earthquake on March 11, 2011, a 15-metre tsunami disabled the power supply and cooling of three Fukushima reactors, causing a nuclear accident. Tepco, who operated the plant and has been tasked with cleaning up the worst nuclear incident, since the 1986 Chernobyl disaster in the former Soviet Union, has been some problems of late in its cleanup operation.

Recently, an exploratory robot malfunctioned and died after being sent inside reactor 2, in mid-February, due to exposure to “unimaginable” levels of radiation, close to 650 sieverts per hour. The previous highest recorded level was 73 sieverts per hour. Following the incident, Naohiro Masuda, president of Tepco’s Fukushima Daiichi Decommissioning project, told reporters the company had to rethink its methods in order to examine and extract the hazardous material stuck in the plant’s second reactor.

We should think out of the box so we can examine the bottom of the core and how melted fuel debris spread out,” Masuda said, according to the Japan Times.

Tepco has been attempting to locate melted fuel which leaked from the reactor’s pressure vessel and is believed to have settled at the bottom of the containment vessel that holds the contaminated water. So far, no such debris has been found, and Tepco decided to extend the survey by one day through Wednesday.

A robot sent by the company on March 20 reached the bottom but was unable to locate the melted fuel due to some pipes that blocked its view.  But it was able to take pictures of what appeared to be sand piling up near the pipes. The radiation readings near them were 6.3 sieverts per hour.

Judging from the radiation level, there is a high possibility that what is piling up on the pipes is not nuclear fuel,” a Tepco official said, according to the Asahi Shimbun

Cleaning up the plant may take an estimated 40 years and cost an estimated 21.5 trillion yen ($189 billion), according to the Guardian.

https://www.rawstory.com/2017/03/deadly-nuclear-radiation-levels-detected-in-fukushima/

March 23, 2017 Posted by | Fukushima 2017 | , , , | Leave a comment

Lethal radiation levels but no melted fuel found in Fukushima reactor water

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The Unit 2 reactor building at Tokyo Electric Power Co.’s Fukushima Daiichi nuclear power plant.

The level of radiation was measured by a special robot on Sunday at a point about 30cm (one foot) from the bottom of the containment vessel of Reactor 1, the Japan Times reported on Tuesday.

The current radiation level is 11 sieverts per hour, the highest detected in water inside the containment vessel. A person exposed to this amount of radiation would likely die in about 40 minutes, the Japan Times reports.

Sunday’s probe also revealed sandy substances building up at the bottom of the vessel. Tokyo Electric Power Company Holdings (TEPCO) officials, however, dismissed the idea that it might be melted nuclear fuel.

Experts have been looking for the melted fuel, which they believe has been accumulating in tainted water.

In March 2011, a 9.1 earthquake and the 15-meter tsunami that followed disabled the cooling system of Fukushima’s three reactors, causing the worst nuclear incident since the 1986 Chernobyl incident in Ukraine.

TEPCO, which operates the crippled power plant, has been obliged to deal with the consequences of the incident.

In February, a robot sent to explore Reactor 2 broke down because of the “unimaginable” levels of radiation, close to 650 sieverts per hour. This was the first time a robot entered this reactor since the plant’s meltdown in 2011.

Previously, the highest radiation level was recorded one year after the disaster and went up to 73 sieverts per hour.

TEPCO has promised extract the hazardous material stuck in the plant’s second reactor, its president Naohiro Masuda said, according to the Japan Times.

In December, TEPCO nearly doubled the estimated cost for the Fukushima clean-up to $188 billion.

A zone of more than 300 square miles around the plant is currently uninhabitable due to the continuing radiation.

https://www.rt.com/news/381879-fukushima-reactor-radiation-lethal/

 

March 23, 2017 Posted by | Fukushima 2017 | , , , | Leave a comment

Robots Go Into The Fukushima Nuclear Plant Site, But Don’t Come Out

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In 2011, a 9.0 magnitude earthquake off the coast of Japan caused a massive tsunami, which in turn led to the meltdown of three nuclear reactors at the Fukushima Nuclear Power Plant in Fukushima, Japan. As a result, the site went on to release radioactive material for the next three days, becoming only the second such disaster in history–after Chernobyl in 1986–to be classified a Level 7 event on the Nuclear Event Scale.

So perhaps it should come as no surprise that, just past the tragedy’s six year anniversary, Tokyo Electric Power Co. (Tepco) has made little progress in cleaning up the disaster site. 

While Tepco has spent much of its time containing radiation and attempting to minimize groundwater contamination, its current mission is to locate and retrieve 600 tons of melted nuclear fuel rods lost somewhere in the radioactive wreckage. As the levels of radiation are still too high for human exposure, this task has fallen to robots. Yet so far, even the robots have failed repeatedly to locate the melted fuel rods; instead, they are dying within the reactors they were sent in to survey. 

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The latest device to meet its end was a scorpion-shaped robot built by Toshiba, which entered one of the reactors last month but stalled just 10 feet short of its target in a matter of hours. While it was ultimately undone by the failure of its left roller-belt, the robot was exposed to far higher than expected levels of radiation, which likely interfered with its electronics and prevented it from sending photos that could have shed some light on the location of the melted fuel rods.

Despite being manufactured using special radiation-hardened materials to protect its circuits from exposure, the levels of radiation it encountered within the reactor far exceeded the robot’s tolerance. Two prior robot missions had to be aborted as well after one got stuck and another failed to locate any melted fuel for several days.

Despite the setbacks, Tepco believes it is getting closer to locating the melted fuel, and hopes to begin removal by 2021, but admits it is a long-term project. The Japanese government estimates that it will take upwards of 40 years and $70.6 billion to complete the clean-up.

According to MIT nuclear science professor Jacopo Buongiorno, “the roadmap for removing the fuel is going to be long, 2020 and beyond. The re-solidified fuel is likely stuck to the vessel wall and vessel internal structures. So the debris have to be cut, scooped, put into a sealed and shielded container and then extracted from the containment vessel. All done by robots.”

But that begs the question: what robots? 

None of those they’ve sent in so far has done the trick. What if the technology required to create the chips and robots that are radiation-hardened yet not too weighed down by protective shielding hasn’t even been invented yet? Bloomberg reports that Toshiba intends to send a new robot into Reactor 3 next year at this time to continue the search, but it is still in the development phase, and Toshiba has not yet made design details public.

The good news is that with a 40 year time horizon, the likelihood of technology catching up with Tepco’s needs is fairly good. But when will the site be clean enough so that more people may return to their homes? In the meantime, radioactive boars have been making themselves quite at home there.

http://secondnexus.com/technology-and-innovation/fukushima-robots-keep-dying/

March 21, 2017 Posted by | Fukushima 2017 | , , , | Leave a comment

The illusion of normality at Fukushima

Six years after it suffered a nuclear meltdown, Fukushima appears to have returned to a semblance of normalcy. But there is still a long way to go in terms of cleaning up the site. Martin Fritz reports.

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A filter mask covering the mouth and nose, a headscarf, a helmet, gloves and two layers of socks – they constitute the protective gear that must be worn by any ordinary visitor to the Fukushima nuclear power station. 

Only a few workers now have to wear face masks and hazmat suits, since most of the ground at the site has been sealed with concrete.

“The radiation is now as low as in the Tokyo’s Ginza shopping district,” Tokyo Electric Power Co. (TEPCO) manager Yuichi Okamura assured a group of journalists during their recent visit to the plant.

But the illusion of normality evaporates as soon as the visitors get off their bus and stand within sight of the reactors, with dosimeters indicating radiation levels of around 160 to 170 microsieverts per hour – nearly 2,000 times above what is considered safe.

“We cannot stay here for long,” warns Okamura.

On the surface, it appears that much has changed in Fukushima since the disaster struck six years ago. The clean-up work has evidently made progress.

But the sight of skeletal steel frames, torn walls and broken pipes immediately reminds one of the 17-meter-high tsunami which flooded the facility six years ago and brought its reactors to a complete standstill.

It’s expected to take 30 to 40 years to completely clean up the Fukushima Daiichi plant, which was hit by the world’s worst nuclear disaster since Chernobyl following a magnitude-9 earthquake and the subsequent tsunami. The operation is likely to carry a hefty price tag, with Japanese officials recently estimating it to cost around $189 billion in total.

Today, with 6,000 workers employed, the nuclear power plant is Japan’s largest and most expensive construction site – and it will remain so for decades. “We’re struggling with four problems,” says TEPCO manager Okamura: “Reducing the radiation at the site, stopping the influx of groundwater, retrieving the spent fuel rods and removing the molten nuclear fuel.”

Black lumps in the reactor containment

Progress in these areas, however, is slow. For instance, workers are erecting scaffolding around the collapsed roof of reactor No 1, but it will likely take four more years for the debris there to be cleared away. Only then can the almost 400 old fuel rods be retrieved from the reactor’s holding basin.

In the adjacent reactor No 2, the blue exterior still remains intact. Workers in hazmat suits can be seen walking on a new metal platform halfway up the reactor building.  But behind the wall lies a nuclear nightmare. A robot sent into the reactor in January found highly dangerous black lumps of leaked fuel on a platform in the outer reactor containment.

“There is now fatally high radiation in that part,” says Okamura.

The engineer quickly turns to reactor No 3, where the progress is more obvious. A hydrogen explosion had turned the reactor’s roof into a tangle of bent metal. It took years of work to dismantle this steel scrap and remove the rubble. “Now we’re building a new roof with an integrated hoisting crane,” says Okamura proudly.

“From next year, we would finally be able to close in on the nearly 600 burnt fuel rods,” he noted. But unlike in reactor No 4, the clean-up must be undertaken remotely as the radiation is so strong that people can only stay there for a few minutes. As a result, the construction of the lifting device has already been delayed by several years. 

Unclear conditions

The situation at the reactors raises doubts about the optimism shared by Japanese officials with regard to the orderly decommissioning of the plant. At the next stop, Okamura shows the control center of the underground ice wall that was built to prevent groundwater from leaking into the reactor basements and mixing with radioactive coolant water.

Since its construction, it has managed to reduce the amount of groundwater flowing into the reactor basements. But five sections of the wall have had to be kept open to prevent water inside the reactor basements from rising and flowing out too rapidly.

Despite all these adversities, the Japanese government and TEPCO are planning to decide as early as this summer how to remove the molten nuclear fuel from the reactors.

Even Shunji Uchida, the Fukushima Daiichi plant manager, couldn’t hide his skepticism from the visiting journalists. “Robots and cameras have already provided us with valuable pictures,” says Uchida, adding: “But it is still unclear what is really going on inside.”

http://www.dw.com/en/the-illusion-of-normality-at-fukushima/a-37885120

March 15, 2017 Posted by | Fukushima 2017 | , , , | Leave a comment

Six years on, Fukushima rests its hopes on fearless robots

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As the struggle continues to bring the six-year-old triple nuclear meltdown at Fukushima Daiichi under control, robots are providing a first, albeit expendable, line of assault.

The robots are on a high-tech suicide mission into the nooks and crannies beneath the stricken plant’s three melted-down reactor cores to discover and map an estimated yet elusive 600 tons of molten nuclear fuel.

Radiation levels in these corridors can reach up to 650 sieverts and hour, higher by nine times than the previous highs measured at the plant, which plateaued at a mere 73 sieverts in 2012.

A whole human body dose of 10 sieverts is enough to cause immediate illness and death within a few weeks at most, 650 within a minute.

Levels like those recently found in the snarls and wreckage beneath Fukushima’s reactor No 2, where radiation is more concentrated because, unlike reactor No 1 and 3, it didn’t suffer a hydrogen explosion, are lethal not just to humans but, as it turns out, to robots as well.

The most recent robot that Tokyo Electric Power Co., the owner of the Fukushima plant, sent into the breach of reactor No 2 died in less than a day. The two before that got stuck in narrow passages and were given up for dead, and a third was abandoned after it spent six days searching for the reactor’s melted fuel. Yet one more robot was sacrificed in action while trying to locate one of its lost compatriots.

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Scientists are trying to develop robots better suited to the high radiation intensity. Yet they say the metallic body count is producing results by giving technicians a view of where the melted down fuel is located and helping them produce 3-D models of what it looks like.

The hope is that robots will be doing the heavy lifting when it comes time to dig out the fuel on a decommissioning job now expected to last another 30 to 40 years at a new cost of $189 billion – nearly double estimates released three years ago.

But on behalf of the 6,000 human workers at the site: Better the robots than them.

Six years ago, on March 11, 2011 a 9.0 magnitude earthquake 72 kilometers out to sea slammed a 39-meter tsunami into the Fukushima Daiichi nuclear power plant, causing a triple meltdown. In the days that followed, uranium fuel melted down in three of the six reactors. Explosions in three of the reactor buildings belched radioactive iodine, cesium and other fission by-products into the environment.

In the immediate aftermath, Japan shut down its 42 remaining nuclear reactors. Up to 160,000 people who lived within a 20-kilometer radius of the plant were forced to evacuate homes where they had lived for generations with their families in agricultural Fukushima.

Six years later, the lemming-like march of robots into the still chaotic cleanup of the plant has become a hopeful metaphor for technology accomplishing what is beyond humanity’s grasp, and their deaths are getting a lot of attention.

Tepco is still hewing to its vow of securing the plant by 2050 to 2060, and says that for the first time since the accident it has succeeded in reeling in the threat the wrecked plant poses to the surrounding area. A visual example of that, noted by reporters who took their annual tour of the plant, is that the thousands of workers on site can now work in ordinary work clothes and surgical masks rather than protective gear. And there are fewer workers to count. Where 8,000 were working at the site last year, 2000 fewer are needed now.

Damaged reactor buildings have been reinforced and 1,300 precariously perched spent fuel assemblies at reactor No. 4 that were a potential disaster all their own have been safely removed. The ground has also been covered with a special coating to prevent rainwater from added to Tepco’s water management struggles.

The company’s projection that it will finish the cleanup in the next four decades, however, is viewed skeptically by Japan’s Nuclear Regulatory Authority, which recently told the Guardian newspaper that the effort was still groping in the dark. And many are suspicious that the Tepco’s optimism is just public relations to assure the international community ahead of the 2020 Tokyo Olympics.

Can you go home again?

Another looming nightmare for many thousands of people is the prospect of loosing government financial support if they don’t move back to villages and towns they evacuated, which many environmental groups say are still highly contaminated.

The evacuation orders enacted by Prime Minister Shinzo Abe’s government after the disaster will be stripped later this month, forcing the evacuees back to live in areas that where in the direct path of the disaster.

Abe’s government says it’s safe for people to return to areas where radiation is 20 millisieverts per year or lower. The globally-accepted limit for radiation absorption is 1 millisievert per year, though the IAEA says anything up to 20 millisieverts per year poses no immediate danger to humans. That has been disputed by numerous studies.

Water hazards

At the plant, contaminated water still poses one of the biggest threats to the wider environment. Nearly one million tons of it stored across 1,000 tanks that were collected after the reactors were blasted with seawater to cool them down. More water has poured in as technicians continue to circulate it through the destroyed reactors to keep them cool.

Leaks from these tanks have often contaminated groundwater, and Tepco has struggled to divert the radioactive deluge from spilling into the Pacific Ocean with an underground wall of frozen soil.

The wall looks a bit like the piping behind a refrigerator and sinks 30 meters into the ground. Over the last year, Tepco pumped water into it to begin the freezing process. But some reports say the wall is having less success in another of its tasks – holding back groundwater from leaking into the basements of reactor buildings, which creates yet more contaminated water.

At their six-year anniversary briefing to reporters, Tepco admitted it was conflicted over what to do with the sea it has amassed. The company says it will be able to cleanse much of the water of cesium, strontium and 50 other radionuclides. But they’re still stumped by how to get rid of tritium, a radioactive isotope of hydrogen, which is still in that water.

Tepco is studying two options. One is to simply dilute the water further and dump it into the sea, as tritium naturally occurs in water in microscopic quantities. They’re also considering evaporating all 960,000 tons of it to release the tritium into the atmosphere.

The company says the final decision will be subject to a public hearing process. Should dumping water into the sea – as has happened numerous times before – still be among the considerations, it would doubtless meet the fierce opposition of fishermen, who have struggled with contaminated seawater since the accident.

Robots’ maze hunt

But by far the most technically involved struggle is finding and removing the fuel that melted down in reactor Nos 1, 2 and 3. And for that, enter the robots, each of which has to be shaped to its task.

At reactor No. 2, where the robot crews have been doing most of their work, it’s not yet known if the fuel melted into or through the reactor vessel’s concrete floor. Determining where that fuel is, and how radioactive it is, dictates how the robots will be designed.

And that’s just for this reactor. At reactor Nos 1 and 3, robots will have to be further customized to handle the specifics of each location. With explorations underway at reactor No 2, Tepco says it expects more robots to march into the other reactors by this summer.

At that point, they say, they will set policy on how the melted fuel will be removed, a process that isn’t expect to begin until 2021.

Designing and building what Tepco refers to as “single function robots” takes as long as two years, and that’s only when you know what you are making the robots for.

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One of the robots currently on the drawing board, for instance, would be able to leap over debris. Another that Hitachi is reportedly designing will resemble a snake so it can lower cameras through a grating in reactor No 1 to scope out and photograph melted down fuel there. That will be third Hitachi robot of that design.

Another robot designed by Toshiba, which was widely eulogized throughout the media, was designed to the anatomy of a scorpion. It died at the end of February just shy of a grating through which it might have got a peek of melted down fuel in reactor No 2.

Newer robot designs, according to a Tepco spokesman who talked with Bloomberg, are incorporating fewer wires and circuits and are built with harder parts than their earlier cousins.

But even the robots that peter out in the radiation are providing valuable clues: Toshiba’s scorpion robot sent the first grainy images from within reactor No 2 of a black residue that could actually be the spent fuel it was sent in to find.

Whether the fuel is in discrete piles or has melted to the walls of its containment vessels will present yet new challenges. Tepco and other scientists expect it’s a bit of both. Fuel that oozed and then re-melted inside the core or adhered to other reactor structures will have to be cut out, shoveled up and placed in shielded containers before it can be removed. This will be the robots’ job.

Earning the trust of a suspicious public

Six years of work is doing little to dent public suspicion of nuclear power in a country that previously relied on its 54 reactors to supply 30 percent of its power.

Tepco – which last year was shown to have delayed reporting the initial meltdowns after the catastrophe by 88 days, thus jeopardizing tens of thousands of lives – has a long way to got before it regains trust. Numerous other independent scientists are said by Japanese activists to be massaging data to make the situation look better than it is.

The mistrust is visible both in how slowly Japan is allowing its nuclear reactors go back online, and by the trickle of people who are willing to return to homes in the Fukushima Prefecture from which they were evacuated.

Japan’s reactors, all of which were shut down in the wake of the disaster, must pass the world’s most stringent stress tests before utilities can consider switching them back on. But even after they’re cleared technically, the people living near the plants have to want them back – and not many do.

As of this year, only three nuclear reactors have been switched on since 2011. Two others at the Genkai nuclear power plant on Japan’s Kyushu Island, were green lighted by a local mayor, but now must be approved by seven other surrounding municipalities.

In the most recently available national polls, taken last year on the fifth anniversary of the disaster, 70 percent of the population opposes the reactor restarts.

Among the more than 160,000 people reckoning with the dilemma of moving back to areas affected by radiation, 60 percent report feeling physical, psychological, financial and emotional stress as a result of the disaster, Japan’s NHK television reported. Up to 72,500 of these people still live in government supplied temporary housing.

In Naime, only 4 kilometers northwest of the plant, more than half of the resident have elected not to return, according to government surveys. Levels there recently hover around 0.07 microsieverts per hour, but down the road in Tomioka, they spike to 1.48 microsieverts an hour, more than 30 times levels in downtown Tokyo, showing there are still lingering radiation hotspots.

One group that is not afraid of populating the ghost-towns surrounding the plant are, according to reports, wild boar. The animals, which have grown up without humans around have reportedly grown fearless.

Tamotsu Baba, the mayor of Naime who is pushing for resettlement by the end of the month, told Reuters the boars pose make the town even less hospitable than the threat of radiation.

http://bellona.org/news/nuclear-issues/2017-03-six-years-on-fukushima-rests-its-hopes-on-fearless-robots

March 10, 2017 Posted by | Fukushima 2017 | , , , , | Leave a comment

Proud workers at Fukushima No. 1 nuke plant risk deadly radiation danger

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Workers examine the inside of the No. 2 reactor containment vessel at the Fukushima No. 1 Nuclear Power Plant on Jan. 30, 2017.

Tokyo Electric Power Co. (TEPCO) has failed to grasp the entire picture of melted fuel possibly accumulating inside the container vessel of the No. 2 reactor at the Fukushima No. 1 Nuclear Power Plant. The radiation levels inside the vessel are extremely high, to the extent a human could be killed in less than a minute, and even a robot designed to conduct a probe inside went down quckly.
The Mainichi Shimbun visited the disaster-stricken plant late last year ahead of the sixth anniversary of the nuclear meltdowns at the facility in March.

On the early morning of Dec. 24, 2016, a group of 26 workers assembled at a building housing the No. 2 reactor when it was still dark outside. The workers were from heavy machinery giant IHI Corp. and other companies engaged in disaster recovery work. On top of their protective Tyvek suits, they were wearing special protective ponchos. They also had four-layer gloves on, with plastic tape wrapped around their wrists. The outfit made them sweat though it was the middle of winter.

In order for TEPCO to move ahead with decommissioning work on the No. 1 through No. 3 reactors at the plant, the utility needs to find out how much melted nuclear fuel lies inside the facilities, and where, in the aftermath of the meltdown of 1,496 fuel rods. The 26 workers were tasked with drilling a hole measuring 11.5 centimeters in diameter in the No. 2 reactor’s container vessel to open the way for the probe robot, using a remotely controlled machine.

Ryosuke Ishida, 28, an employee of a related company in Hokkaido, was in charge of removing the machinery that was used in the drilling work. In order to ward off the severely high radiation, he was wearing a lead jacket weighing 10 kilograms on top of his already tightly sealed protective gear. Each worker was allowed only five minutes for their task to keep their radiation exposure doses to no more than 3 millisieverts a day. The dosimeters they were carrying with them were set to beep when the radiation level reached 1.5 to 2 millisieverts, with an additional alarm set to go off when radiation doses hit every one-fifth of those levels.

Ishida’s dosimeter beeped just under a minute after he stepped inside the No. 2 reactor building. “Is it beeping already?” he thought to himself. The radiation levels vary greatly depending on where one stands inside the facility. Although Ishida had got a firm grasp on where the hot spots were during pre-training, he found himself “inadvertently standing on highly radioactive spots as I was focused on work.”

While trying to calm himself down, Ishida sped up his manual work. Alas, a machine component for turning a bolt fell off and rolled on the floor. “Damn, I’m running out of time,” he thought. His full face mask went all white as he sweated physically and emotionally, blocking his view. By the time he finished picking up the fallen component and wrapped up his work, he was sweating all over his body.

“It’s a battle against radiation at the site,” Ishida recalled. He added, though, “Because nobody else wants to do the job, I find it all the more worthwhile and take pride in it.”

http://mainichi.jp/english/articles/20170227/p2a/00m/0na/007000c

February 28, 2017 Posted by | Fukushima 2017 | , , , | Leave a comment

Fukushima: No End in Sight

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KGO Radio: Host Pat Thurston recently interviewed Arnie Gundersen, chief engineer for Fairewinds Energy Education on KGO radio to discuss the latest challenging news from Japan about the Fukushima Daiichi atomic power reactor including the high levels of radiation emanating from the reactors, all the failed robotic expeditions, where we should go from here, as well as how ongoing radioactive releases from the Fukushima Daiichi site may be impacting the west coast of the United States.

 

BBC Newsday: BBC Radio interviewed nuclear engineer Arnie Gundersen to discuss TEPCO’s attempts to send a special robot into Fukushima Daiichi Reactor #2 in Japan to investigate the obstacles in the way of TEPCO’s progress determining the location and condition of the atomic fuel. Unfortunately even this specially designed robot failed in its attempt to clear the path for additional investigations as the nuclear radioactivity was so high, it shut down the robots before they could complete their mission.

Listen Here

 

Enviro News: The astronomical radiation readings at Fukushima Daiichi Reactor #2 of 530 Sv/hr complicate the already complex task of decommissioning the plant. These levels are so radioactive that a human would be dead within a minute of exposure and specially designed robots can only survive for about 2 hours. Fairewinds chief engineer Arnie Gundersen says that the best solution would be to entomb the reactors, similar to the sarcophagus entombing Chernobyl, for at least 100-years, otherwise the radiation level that workers would be exposed to is simply too dangerous.
Read the whole article here

 

 

Are the meltdowns at Fukushima Daiichi over? The answer is no. Made all the more prevalent a year out from it’s initial release by the recent robotic expeditions into Reactor #2 which gave us a clearer picture on just how deadly the radiation levels are, watch Chief Engineer and nuclear expert Arnie Gundersen inform viewers on what’s going on at the Japanese nuclear meltdown site, Fukushima Daiichi. As the Japanese government and utility owner Tokyo Electric Power Company push for the quick decommissioning and dismantling of this man-made disaster, the press and scientists need to ask, “Why is the Ukrainian government waiting at least 100 years to attempt to decommission Chernobyl, while the Japanese Government and TEPCO claim that Fukushima Daiichi will be decommissioned and dismantled during the next 30 years?”
Like so many big government + big business controversies, the answer has nothing to do with science, and everything to do with politics and money. To understand Fukushima Daiichi, you need to follow the money.

http://www.fairewinds.org/newsletter-archive//no-end-in-sight

February 23, 2017 Posted by | Fukushima 2017 | , , , , | Leave a comment

Fukushima nuclear disaster evacuees ‘pressured’ to return to contaminated homes, says Greenpeace

Even though radiation levels in a village near the site of the Fukushima nuclear disaster still exceed international guidelines, its evacuated residents are being coerced to return, according to a Greenpeace report.

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Residents from the Japanese ghost village of Iitate will be allowed to return to their former homes at the end of March – the first time since they were forced to flee the Fukushima nuclear disaster in 2011. That’s the date the Japanese government has set to lift evacuation orders.

But according to environmental organization Greenpeace, it’s uncertain whether many will want to. Greenpeace says tests it has carried out on homes in Iitate show that despite decontamination, radiation levels are still dangerously high – but that’s not stopping the Japanese governmenment from pressuring evacuees from returning, under threat of losing financial support.

Those who refuse to go back to their former homes, and are dependent on the Japanese government’s financial help, are faced with a dilemma. After a year from when an area is declared safe again to live in, evacuated residents will see their compensation payments terminated by the government.

Radiation ‘comparable with Chernobyl’

The nuclear disaster led to more than 160,000 people being evacuated and displaced from their homes. Of these, many tens of thousands are still living in temporary accommodation six years on.

The village of Iitate, lying northwest of the destroyed reactors at Fukushima Daiichi power plantand from which 6,000 citizens had to be evacuated, was one of the most heavily contaminated following the nuclear disaster.

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Government employees monitor radiation at a day-care center in Iitate in 2011

Around 75 per cent of Iitate is mountainous forest, an integral part of residents’ lives before the nuclear accident.

But according to Greenpeace’s report, published on Tuesday, radiation levels in these woods are “comparable to the current levels within the Chernobyl 30km exclusion zone – an area that more than 30 years after the accident remains formally closed to habitation.”

Put another way, Greenpeace said that in 2017, there clearly remains a radiological emergency within Iitate – defining emergency thus: “If these radiation levels were measured in a nuclear facility, not Iitate, prompt action would be required by the authorities to mitigate serious adverse consequences for human health and safety, property or the environment.”

The environmental organization says decontamination efforts have primarily focused on the areas immediately around peoples’ homes, in agricultural fields and in 20-meter strips along public roads.

But these efforts ended up generating millions of tons of nuclear waste – these now lie at thousands of locations across the prefecture, but they haven’t reduced the level of radiation in Iitate “to levels that are safe,” says Greenpeace.

‘Normalizing’ nuclear disaster?

The organization has accused the Japanese government of trying “to normalize a nuclear disaster, creating the myth that just years after the widespread radioactive contamination caused by the nuclear accident of 11 March 2011, people’s lives and communities can be restored and reclaimed.

“By doing so, it hopes, over time, to overcome public resistance to nuclear power.”

Greenpeace also lambasted the government for leaving unanswered what it calls a critical question for those trying to decide whether to return or not: what radiation dose will they be subjected to, not just in one year but over decades or a lifetime?

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Greenpeace says Japan’s government wants to restore public confidence in nuclear power at the cost of harming residents

“Until now the Japanese government has exclusively focused on annual radiation exposure and not the potential radiation dose rates returning citizens could potentially face over their entire lifetime,” says Greenpeace.

Greenpeace, which has been monitoring Iitate since 2011, carried out its latest survey in November 2016

It found that the average radiation dose range for Iitate beginning from March 2017 over a 70-year lifetime was between 39 millisieverts (mSv) and 183mSv – and that’s not including natural radiation exposure expected over a lifetime, or the exposure received in the days, weeks and months following the March 2011 nuclear disaster.

That exceeds yearly guidelines set by the International Commission on Radiological Protection (ICRP) when added up over a 70-year period – it puts the maximum recommended radiation exposure at 1mSv annually.

Greenpeace says: “The highly complex radiological emergency situation in Iitate, and with a high degree of uncertainty and unknown risks, means that there is no return to normal in Iitate, Fukushima prefecture.”

It has called on the Japanese government to cease its return policy, and to provide full financial support to evacuees, and “allow citizens to decide whether to return or relocate free from duress and financial coercion.”

According to Greenpeace, “for the more than 6,000 citizens of Iitate, this is a time of uncertainty and anxiety.”

Heinz Smital, nuclear physicist and radiation expert at Greenpeace Germany, and part of the team taking measurements at Iitate, told DW the residents were faced with a very difficult situation.

“If you decide to live elsewhere [and not return to Iitate], then you don’t have money, you’re sometimes not welcomed in another area so you are forced to leave, because people say, ‘you’re not going back but you could go back,'” he said. “But for people who go back, they have contaminated land, so how can they use the fields for agriculture?”

He urged the Japanese government to more involve those affected in the decision-making process and not try to give an impression that things are “going back to normal.”

“It’s a violation of human rights to force people into such a situation because they haven’t done anything wrong, it’s the operator of the power plant responsible for the damage it caused,” said Smital.

“It’s very clear that there’s very serious damage to the property and the lifestyle of the people but the government doesn’t care about this.”

http://www.dw.com/en/fukushima-nuclear-disaster-evacuees-pressured-to-return-to-contaminated-homes-says-greenpeace/a-37639353

February 23, 2017 Posted by | Fukushima 2017 | , , | Leave a comment

FOCUS: Failed Survey Complicates N-Fuel Removal at Fukushima Plant

It looks like its too radioactive for robots to survive. I wonder how they will do this work now?

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Tokyo, Feb. 20 (Jiji Press)–A failed robot survey of melted nuclear fuel that has dropped through the bottom of a damaged reactor pressure chamber at the Fukushima No. 1 nuclear plant complicates the formulation of a policy in the summer for taking out the fuel debris.
The removal of the molten nuclear fuel is regarded as the most demanding challenge in the decommissioning of the disaster-stricken plant’s reactors, said to take 30 to 40 years.
Tokyo Electric Power Company Holdings Co. <9501>, the manager of the plant in Fukushima Prefecture, northeastern Japan, is discussing the drawing up of a broad policy outline before conducting an additional survey to work out a detailed plan for the nuclear fuel removal, company officials said.
TEPCO’s initial plan called for a self-propelled survey robot, dubbed scorpion, to enter the No. 2 reactor’s containment vessel and travel on a 7.2-meter rail to reach a metal grating directly beneath the reactor’s damaged pressure chamber. The robot would have surveyed the extent of damage to the chamber, while locating melted nuclear fuel that is believed to have dropped through the metal grating to the bottom of the containment vessel and shooting the fuel’s images.
The No. 2 reactor is one of the three units that suffered meltdown due to the failure of their cooling systems caused by the March 2011 earthquake and tsunami.

http://jen.jiji.com/jc/eng?g=eco&k=2017022000007

February 21, 2017 Posted by | Fukushima 2017 | , , | Leave a comment

Melted Nuclear Fuel Search Proceeds One Dead Robot at a Time

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The latest robot seeking to find the 600 tons of nuclear fuel and debris that melted down six year ago in Japan’s wrecked Fukushima Dai-Ichi power plant met its end in less than a day.

The scorpion-shaped machine, built by Toshiba Corp., entered the No. 2 reactor core Thursday and stopped 3 meters (9.8 feet) short of a grate that would have provided a view of where fuel residue is suspected to have gathered. Two previous robots aborted similar missions after one got stuck in a gap and another was abandoned after finding no fuel in six days.

After spending most of the time since the 2011 disaster containing radiation and limiting ground water contamination, scientists still don’t have all the information they need for a cleanup that the Japanese government estimates will take four decades and cost 8 trillion yen ($70.6 billion). It’s not yet known if the fuel melted into or through the containment vessel’s concrete floor, and determining the fuel’s radioactivity and location is crucial to inventing the technology needed to remove it. 

The roadmap for removing the fuel is going to be long, 2020 and beyond,” Jacopo Buongiorno, a professor of nuclear science and engineering at the Massachusetts Institute of Technology, said in an e-mail. “The re-solidified fuel is likely stuck to the vessel wall and vessel internal structures. So the debris have to be cut, scooped, put into a sealed and shielded container and then extracted from the containment vessel. All done by robots.”

Read more: Robots are being utilized to clean up U.K.’s nuclear waste

To enter a primary containment vessel, which measures about 20 meters at its widest, more than 30 meters tall and is encased in meters of concrete, outside air pressure is increased to keep radiation from escaping and a sealed hole is opened that the robot passes through. Three reactors at the plant suffered meltdowns, and each poses different challenges and requires a custom approach for locating and removing the fuel, said Tatsuhiro Yamagishi, Tokyo Electric Power Co. Holdings Inc. spokesman.

The machines are built with specially hardened parts and minimal electronic circuitry so that they can withstand radiation, if only for a few hours at a time. Thursday’s mission ended after the robot’s left roller-belt failed, according to Tokyo Electric, better known as Tepco. Even if it had returned, this robot, like all others so far designed to aid the search for the lost fuel, was expected to find its final resting place inside a reactor.

No. 1 Unit

Hitachi Corp. in the next two months plans to send a machine into the No. 1 reactor core that scientists hope can transmit photos of the fuel and measure radiation levels.

The snake-like robot will lower a camera on a wire from a grate platform in the reactor to take photos and generate 3-D models of the bottom of the containment vessel. This will be the third time Hitachi sends in this robot design.

While the company is hopeful this robot will find some of the fuel, it will likely be unable to find all of it, according to Satoshi Okada, a Hitachi engineer working on the project. The company is already planning the next robot voyage for after April.

We are gathering information so that we can decide on a way to remove the fuel,” said Okada. “Once we understand the situation inside, we will be able to see the way to remove the fuel.”

No. 2 Unit

On Thursday, Toshiba’s scorpion-like robot entered the reactor and stopped short of making it onto the containment vessel’s grate. While Tepco decided not to retrieve it, the company views the attempt as progress.

We got a very good hint as to where the fuel could be from this entire expedition” Tepco official Yuichi Okamura said Thursday at a briefing in Tokyo. “I consider this a success, a big success.”

Tepco released images last month of a grate under the No. 2 reactor covered in black residue that may be the melted fuel — one of the strongest clues yet to its location. The company measured radiation levels of around 650 sieverts per hour through the sound-noise in the video, the highest so far recorded in the Fukushima complex.

A short-term, whole-body dose of over 10 sieverts would cause immediate illness and subsequent death within a few weeks, according to the World Nuclear Association.

The Hitachi and Toshiba robots are designed to handle 1,000 sieverts and no robot has yet been disabled due to radiation.

Radiation levels near the fuel are lethal,” said MIT’s Buongiorno, who holds the university’s Tepco chair, a professorship based on an initial donation by the company 10 years ago. There are no formal affiliations or obligations for the faculty who receive the chair, he said.

Because the No. 2 unit is the only one of the three reactors that didn’t experience a hydrogen explosion, there was no release into the atmosphere and radiation levels inside the core are higher compared to the other two units, according to the utility.

No. 3 Unit

Tepco’s balance sheet has been strapped by ballooning Fukushima cleanup costs and slumping national power demand. All of the company’s nuclear power plants remain shut since it halted the No. 6 reactor at its Kashiwazaki Kariwa station in March 2012. The company is seeking drastic changes in top management in consultation with the Japanese government, TV Asahi reported Friday, without attribution.

The utility has focused on removing spent fuel in the upper part of the reactor building, which Toshiba aims to extract with a claw-like system. This fuel didn’t melt and is still in a pool that controls its temperature.

The used-fuel in No. 3 is scheduled to begin removal before the end of the decade, the first among the three reactors that melted down. Toshiba is developing another robot to search for melted fuel, planned to enter sometime in the year ending March 2018. The company hasn’t announced yet the design or strategy.

https://about.bnef.com/blog/race-for-japans-melted-nuclear-fuel-leaves-trail-of-dead-robots/

February 21, 2017 Posted by | Fukushima 2017 | , , , | Leave a comment

Operation of communication about the “scorpion” robot which will be sent to the confinement enclosure of reactor n ° 2

TEPCO and its partners launched a communication operation about the “scorpion” robot, which will be sent to the containment reactor of reactor n ° 2 in an attempt to locate the corium, ie the highly radioactive molten fuel, mixed with debris. It is not certain that the mission will be a success, the cleaning robot having lasted only two hours in this enclosure because of the extreme radiations, without being able to finish its task.

A press release announces what we already know and insists on the challenges: “every step is a new challenge for TEPCO, but TEPCo welcomes the challenges”. The company would be almost happy with the accident? It is accompanied by a promotional video with a comparison to the kendô fights posted on its Facebook page.

http://www.tepco.co.jp/en/press/corp-com/release/2017/1377951_10469.html

https://www.facebook.com/OfficialTEPCOen/videos/1346869308705698/

The Japanese nuclear industry wants to place itself on the decommissioning market and highlights the technologies being developed. This robot was designed by IRID, Toshiba and TEPCO. IRID benefits from public funds. As for Toshiba, it is almost bankrupt because of its nuclear branch and TEPCO is financially in a bad shape.

The press release and the video do not provide any relevant information and are in complete discrepancy with reality.

1. Current conditions of Unit 2 Primary Containment Vessel (PCV)

Nuclear fuel in the Primary Containment vessel (PCV) was exposed to the air and melted from the impact of March 2011 Great Earthquake.

As a result of the accident analysis, it was found that a portion of melted nuclear fuel might have been fallen inside the pedestal.

To remove fuel debris, it is necessary to investigate the PCV and clarify the conditions of debris and surrounding structures.

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2. Outline of Unit 2 PCV investigation

[Purpose]: To obtain feedback information (deformation of platform, etc.) for the design and

development of next investigation devices inside the pedestal

To inspect conditions on the platform inside pedestal, fuel debris fallen to the CRD housing, and conditions of structures inside pedestal.

[Investigation point]: Platform and Control Rod Drive (CRD) will be investigated from the platform inside pedestal

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3. Work steps for Unit 2 PCV investigation

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4. Preparatory investigation results from X-6 penetration to CRD rail

 

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4. Preparatory investigation results at the entrance of pedestal area

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4. Preparatory investigation results of pedestal area

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5. Additional results expected from the self-propelled investigation device

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6. Investigation by the self-propelled investigation device to the end of CRD rail

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6. Investigation by the self-propelled investigation device to the end of CRD rail

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Reference: Investigation results on the platform inside the pedestal

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Technical information for the media is available here:

In Japanese about the upcoming mission http://www.tepco.co.jp/nu/fukushima-np/handouts/2017/images1/handouts_170215_08-j.pdf

And in English http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2017/images/handouts_170215_01-e.pdf

And about radiation protection measures http://www.tepco.co.jp/nu/fukushima-np/handouts/2017/images1/handouts_170215_09-j.pdf

And in English http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2017/images/handouts_170215_02-e.pdf

Translated from L’ACROnique de Fukushima http://fukushima.eu.org/operation-de-communication-sur-le-robot-scorpion-qui-va-etre-envoye-dans-lenceinte-de-confinement-du-reacteur-n2/

 

February 17, 2017 Posted by | Fukushima 2017 | , , , , | Leave a comment

HELEN CALDICOTT: The Fukushima nuclear meltdown continues unabated

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Dr Helen Caldicott, explains recent robot photos taken of Fukushima’s Daiichi nuclear reactors: radiation levels have not peaked, but have continued to spill toxic waste into the Pacific Ocean — but it’s only now the damage has been photographed.

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 gaoled 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.

https://independentaustralia.net/politics/politics-display/helen-caldicott-the-fukushima-nuclear-meltdown-continues-unabated,10019

February 13, 2017 Posted by | Fukushima 2017 | , , | 1 Comment

Clean-up robot pulled from Fukushima Reactor 2 due to extremely high radiation

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Cleaner Robot Pulled From Fukushima Reactor Due to Immense Radiation

The camera on the bot was compromised by the high levels of radiation.

A remote-controlled cleaning robot sent into a damaged reactor at Japan’s Fukushima nuclear plant had to be removed Thursday before it completed its work because of camera problems most likely caused by high radiation levels.

It was the first time a robot has entered the chamber inside the Unit 2 reactor since a March 2011 earthquake and tsunami critically damaged the Fukushima Da-ichi nuclear plant.

Tokyo Electric Power Co. said it was trying to inspect and clean a passage before another robot does a fuller examination to assess damage to the structure and its fuel. The second robot, known as the “scorpion,” will also measure radiation and temperatures.

Thursday’s problem underscores the challenges in decommissioning the wrecked nuclear plant. Inadequate cleaning, high radiation and structural damage could limit subsequent probes, and may require more radiation-resistant cameras and other equipment, TEPCO spokesman Takahiro Kimoto said.

“We will further study (Thursday’s) outcome before deciding on the deployment of the scorpion,” he said.

TEPCO needs to know the melted fuel’s exact location and condition and other structural damage in each of the three wrecked reactors to figure out the best and safest ways to remove the fuel. It is part of the decommissioning work, which is expected to take decades.

During Thursday’s cleaning mission, the robot went only part way into a space under the core that TEPCO wants to inspect closely. It crawled down the passage while peeling debris with a scraper and using water spray to blow some debris away. The dark brown deposits grew thicker and harder to remove as the robot went further.

After about two hours, the two cameras on the robot suddenly developed a lot of noise and their images quickly darkened — a sign of a problem caused by high radiation. Operators of the robot pulled it out of the chamber before completely losing control of it.

The outcome means the second robot will encounter more obstacles and have less time than expected for examination on its mission, currently planned for later this month, though Thursday’s results may cause a delay.

Both of the robots are designed to withstand up to 1,000 Sieverts of radiation. The cleaner’s two-hour endurance roughly matches an estimated radiation of 650 Sieverts per hour based on noise analysis of the images transmitted by the robot-mounted cameras. That’s less than one-tenth of the radiation levels inside a running reactor, but still would kill a person almost instantly.

Kimoto said the noise-based radiation analysis of the Unit 2’s condition showed a spike in radioactivity along a connecting bridge used to slide control rods in and out, a sign of a nearby source of high radioactivity, while levels were much lower in areas underneath the core, the opposite of what would normally be the case. He said the results are puzzling and require further analysis.

TEPCO officials said that despite the dangerously high figures, radiation is not leaking outside of the reactor.

Images recently captured from inside the chamber showed damage and structures coated with molten material, possibly mixed with melted nuclear fuel, and part of a disc platform hanging below the core that had been melted through.

http://www.popularmechanics.com/science/energy/a25155/cleaner-robot-pulled-from-fukushima-reactor-due-to-radiation/?src=socialflowTW

 

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Extremely high radiation breaks down Fukushima clean-up robot at damaged nuclear reactor

A clean-up mission using a remotely operated robot at Japan’s crippled Fukushima nuclear plant has had to be aborted, as officials feared they could completely lose control of the probe affected by unexpectedly high levels of radiation.

The robot equipped with a high-pressure water pump and a camera designed to withstand up to 1,000 Sieverts of cumulative exposure had been pulled off the inactive Reactor 2 at the Fukushima Daiichi nuclear complex earlier this week, The Japan Times reported Friday, citing the plant operator, Tokyo Electric Power Company (TEPCO). The device reportedly broke down just two hour into the probe.

The failure led experts to rethink estimated levels of radiation inside the damaged reactor.

While last week TEPCO said it might stand at 530 Sieverts per hour – a dose that can almost instantly kill a human being, following the latest aborted mission a company official has said a reading of up to 600 Sieverts should be “basically correct.”

Even despite the considerable 30-percent margin of error for the revised estimate, the latest probe left no doubt that radiation levels are at record highs within the reactor. Even though it cannot be measured directly with a Geiger counter or dosimeter, the dose is calculated by its effect on the equipment.

Last month, a hole of no less than one square meter in size was discovered beneath the same reactor’s pressure vessel. The apparent opening in the metal grating is believed to have been caused by melted nuclear fuel, TEPCO then said.

The recent mission has demonstrated that the melted fuel is close to the studied area.

 

While extreme radiation levels have been registered within the reactor, officials insist that no leaks or increases outside have been detected.

The failure might force Japan to rethink the robot-based strategy it has adopted for locating melted fuel at Fukushima, according to The Japan Times.

The robot affected by radiation was supposed to wash off thick layers of dirt and other wreckage, clearing ways for another remotely controlled probe to enter the area, tasked with carrying out a more proper investigation to assess the state of the damaged nuclear reactor. Previously, even specially-made robots designed to probe the underwater depths beneath the power plant have crumbled and shut down affected by the radioactive substance inside the reactor.

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The Fukushima Daiichi nuclear power plant suffered a blackout and subsequent failure of its cooling systems in March 2011, when it was hit by an earthquake and tsunami. Three of the plant’s six reactors were hit by meltdowns, making the Fukushima nuclear disaster the worst since the Chernobyl catastrophe in Ukraine in 1986. TEPCO is so far in the early stages of assessing the damage, with the decommissioning of the nuclear facility expected to take decades.

https://www.rt.com/news/377025-fukushima-radiation-breaks-robot/

February 13, 2017 Posted by | Fukushima 2017 | , , , | Leave a comment

Fukushima Is Still Melting Down…

 

Kevin Kamps, Beyond Nuclear. Almost 6 years after a massive meltdown – radiation levels at the crippled Fukushima Daiichi power plant in Japan are as dangerously high as ever. So is nuclear power ever worth the risk?

….A number of commentators, Arnie Gundersen at Fairwinds, Kendra Ulrich at Greenpeace International, Nancy Foust at Simply Info, have pointed out that the levels of radioactivity that are being talked about by Tokyo Electric (TEPCO), 53,000 rem per hour levels  that were documented just a week ago have probably been there this whole time since March 2011 since the meltdown happened because what they are doing is they are getting closer where the melted core is at, they still don’t know where they ‘re at but what they are doing they are getting closer to that dangerous place and so sure enough it stands to reason that they would find these levels….

http://www.thomhartmann.com/bigpicture/fukushima-still-melting-down

February 13, 2017 Posted by | Fukushima 2017 | , , , | Leave a comment