Visualizing nuclear radiation: Team images gamma rays to help decontaminate Fukushima

visualizingn

A Kyoto University team has developed a new camera to visualize radioactive hotspots

Extraordinary decontamination efforts are underway in areas affected by the 2011 nuclear accidents in Japan. The creation of total radioactivity maps is essential for thorough cleanup, but the most common methods, according to Kyoto University’s Toru Tanimori, do not ‘see’ enough ground-level radiation.

“The best methods we have currently are labor intensive, and to measure surface radiation accurately,” he says, “complex analysis is needed.”

In their latest work published in Scientific Reports, Tanimori and his group explain how gamma-ray imaging spectroscopy is more versatile and robust, resulting in a clearer image.

“We constructed an Electron Tracking Compton Camera (ETCC) to detect nuclear gamma rays quantitatively. Typically this is used to study radiation from space, but we have shown that it can also measure contamination, such as at Fukushima.”

The imaging revealed what Tanimori calls “micro hot spots” around the Fukushima Daiichi Nuclear Power Plant, even in regions that had already been considered decontaminated. In fact, the cleaning in some regions appeared to be far less than what could be measured by other means.

Current methods for measuring gamma rays do not reliably pinpoint the source of the radiation. According to Tanimori, “radiation sources including distant galaxies can disrupt the measurements.”

The key to creating a clear image is taking a color image including the direction and energy of all gamma rays emitted in the vicinity.

“Quantitative imaging produces a surface radioactivity distribution that can be converted to show dosage on the ground,” says Tanimori. “The ETCC makes true images of the gamma rays based on proper geometrical optics.”

This distribution can then be used to relatively easily measure ground dosage levels, showing that most gamma rays scatter and spread in the air, putting decontamination efforts at risk.

“Our ETCC will make it easier to respond to nuclear emergencies,” continues Tanimori. “Using it, we can detect where and how radiation is being released. This will not only help decontamination, but also the eventual dismantling of nuclear reactors.”

https://phys.org/news/2017-03-visualizing-nuclear-team-images-gamma.html#jCp

Fury sparked in Japan as companies found duping foreign refugees into decontamination work in Fukushima

TOKYO, March 17 (Xinhua)– “Such scams are a shame to Japan,” said a reporter from Tokyo Metropolitan Television Broadcasting Corp., referring to a recently-exposed scandal involving labor dispatch agencies duping foreign refugees into doing decontamination work in Fukushima.

Various local media have exposed recently that some Japanese companies have swindled foreign refugees into doing decontamination work in Fukushima with empty promises that such work might help extend their visas to stay in Japan.

Fifty-year-old Hosein Moni and 42-year-old Hosein Deroaru from Bangladesh were both caught in such a scam, according to a recent report by the Chunichi Shimbun, one of the largest newspapers in Japan.

The two came to Japan in 2013 seeking to be recognized as political refugees. In Japan, foreigners are given temporary permission to stay for up to six months at one application before they are recognized as refugees and given status as residents.

According to government data, the number of refugees actually afforded recognition as refugees in Japan is disproportionately low among developed nations, while the numbers of those applying for refugee status has been rapidly increasing in recent years in Japan.

The government received some 5,000 such applications in 2014, but only 11 were granted refugee status, according to the data.

Moni and Deroaru were told by a so-called labor dispatch agency in Nagoya that they could do decontamination work in exchange for an extension of their visa.

The two, knowing little Japanese and trying to seize every opportunity they could, accepted the job and worked in Fukushima for three months in 2015.

But when they finished their work and went to the local immigration bureau to extend their stay, they were told by officers there that they knew nothing about such a policy.

They later found out that the construction company that had hired them had changed its company name, and its Fukushima branch had closed.

Half of the 20 workers that they had worked with in Fukushima were foreigners, many of whom had been applying for refugee status in Japan, the pair later recalled.

Their work mainly involved clearing away contaminated soil with spades, and while they were at work might well have been affected by high levels of radiation. “The radiation detectors we brought with us kept sounding alarms, which was rather scary,” they were quoted as saying.

The incident, after been exposed by local media, also caused a splash on social network sites. Many Japanese netizens felt indignant that such scams were happening in their homeland.

“Earthquake, nuclear plant, poverty… there are always some people trying to cheat or hurt other people here just for money,” remarked Kojima on Twitter.

“Why has my home country degenerated to such a low place,” said “Hootoo,” another netizen here.

They also called on the Japanese government to strengthen regulations on the Japanese companies to prevent such scams from happening.

Japan’s immigration bureau, for its part, said that the incident was with “vile nature”, and it would conduct investigations soon.

In fact, however, for a long time, due to lack of manpower, many of Japan’s “three-K” (kiken, kitanai, kitsui, which means dangerous, dirty and tiring) jobs have been done by foreign immigrants, as the Japanese are reluctant to do such work.

“As Japanese people don’t want to do the work, it has to be done by foreigners,” said Ishikawa, a Brazil-born Japanese who was in charge of coordinating foreign workers in decommissioning work linked to the Fukushima Daiichi Nuclear Plant, according to a report published by the Mainichi Shimbun last year.

Most of the foreign workers could hardly speak Japanese. As anti-radiation brochures provided by the plant’s operator, Tokyo Electric Power Company Holdings Inc. (TEPCO), were only available in Japanese or English, many of the workers could not understand it, Ishikawa was quoted as saying.

The foreign workers, to some extent, saved the contractors and TEPCO by pushing forward the decommissioning work of the nuclear plant, remarked the report.

A magnitude-9.0 earthquake in 2011 triggered a massive tsunami which destroyed the emergency power and then the cooling system of the Fukushima Daiichi nuclear power plant, and caused a serious nuclear disaster, forcing some 300,000 people to evacuate.

The operator of the crippled Fukushima Daiichi nuclear plant, has said it plans to decommission the crippled reactors in about four decades.

However, the difficult tasks such as processing contaminated water, cooling the reactors and removing nuclear fuel and debris, continue to pose serious challenges to the power company as well as the government.

http://news.xinhuanet.com/english/2017-03/17/c_136137295.htm

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.

37863971_303.jpg

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

Decontamination work in Fukushima Pref. far from finished business

c.jpg

 

FUKUSHIMA — With six years having passed since the onset of the nuclear disaster at Tokyo Electric Power Co. (TEPCO)’s Fukushima No. 1 nuclear plant, the government’s decontamination plan in this prefecture is fast approaching the end of its first phase at the end of March.
As a consequence of the decontamination project — and the fact that radioactive material decays over time — radiation levels in Fukushima Prefecture have declined to some extent.

However, in certain areas of the prefecture, radiation levels continue to be high, and the issue of what to do with decontamination waste still needs to be tackled. The government does plan to carry out decontamination work in the neglected “difficult-to-return” evacuation zones in fiscal 2017, but local residents are skeptical that the end is near.

To date, the Environment Ministry has carried out decontamination work in 11 municipalities across the prefecture subject to evacuation orders. However, no decontamination has been done yet in the “difficult-to-return” zones. In other municipalities, where the radiation dose is 0.23 microsieverts per hour or higher, decontamination work has been performed by the relevant local government office.

Initially, the central government-led decontamination was supposed to finish in March 2014, but this was pushed back to March 2017, owing to delays related to makeshift storage sites for contaminated soil. The Environment Ministry plans to finish its decontamination work by the end of March 2017, after which it plans to move the contaminated soil to interim storage facilities.

In areas where the central government is in charge of decontamination, “follow-up” decontamination will also take place in the event that radiation levels do not drop enough, in the hope that residents will eventually be able to return home. Conversely, there will be no follow-up in cases where decontamination is being handled by a local authority, making local residents anxious.

Nevertheless, there are a few spots where follow-up decontamination has taken place in addition to the work in the 11 municipalities overseen by the government. There are nine such spots in total, and they are all in the city of Soma. The Soma Municipal Government initially intended to conduct decontamination in about 30 locations across the city, but this was eventually reduced to nine locations, owing to radiation level-related criteria for follow-up decontamination as instructed by the Environment Ministry.

A Soma Municipal Government representative stated, “Radiation levels are particularly high in forests here, and it is unknown what the future impact of this might be. I want to have a system set up whereby decontamination can be easily conducted again in the future, as necessary.” (By Hanayo Kuno, Science & Environment News Department, Kazuhisa Soneda, Fukushima Bureau, Makoto Ogawa, News Layout Center, and Yohei Kanno, Visual Group)

http://mainichi.jp/english/articles/20170311/p2a/00m/0na/027000c

Fukushima Radioactive Debris: 2 Bangladeshis tricked into cleanup job

Two Bangladeshi asylum seekers in Japan cleared up radioactive contamination from one of the world’s worst nuclear disasters on the false promise doing so would win them permission to stay in the country longer, media reported yesterday.

The Fukushima nuclear plant suffered multiple meltdowns after being hit by a tsunami triggered by a big earthquake on March 11, 2011. Companies decontaminating areas around the plant, which usually involves removing radioactive top soil, have struggled to find workers willing to do the job.

The two men, who arrived in Japan in 2013 saying they were escaping political persecution, said they were told by brokers and construction companies that their visas would be extended if they did decontamination work, the Chunichi newspaper reported.

“We believed the visa story because they said it’s a job Japanese people don’t want to do,” Chunichi quoted one of the men, Monir Hossain, as saying.

Reuters was not able to reach the two men.

The men did the decontamination work in Iitate village, about 50 km (30 miles) south of the plant, from January to March 2015, Chunichi said.

Japan maintains tight controls on the entry of foreign workers but asylum seekers are allowed to work while their applications are reviewed. Many have permits allowing them to stay and work that have to be renewed every six months.

Mitsushi Uragami, a justice ministry official who oversees refugee recognition, said there were no residence permits on offer for people doing decontamination.

“The length of asylum seekers’ residence permits and them doing decontamination work are unrelated. If anyone is giving inaccurate explanations about this, it’s problematic,” Uragami told Reuters.

The department was investigating the case, he said.

Takuya Nomoto, an environment ministry official overseeing decontamination, said the Chunichi report did not give the names of the companies or labour brokers involved, and as such the ministry was not able to confirm it.

“The ministry expects all contractors involved in decontamination to comply with the law,” he said.

The Fukushima Labour Bureau said this month more than half of the 1,020 companies involved in decontamination violated labour and safety laws last year.

Reuters revealed in 2013 that homeless men were put to work clearing radioactive soil and debris in Fukushima for less than the minimum wage.

Reuters also found the clean-up depended on a little scrutinised network of subcontractors – many of them inexperienced with nuclear work and some with ties to organised crime.

http://www.thedailystar.net/backpage/fukushima-nuke-debris-2-bangladeshis-tricked-cleanup-job-1373098

Fukushima laden with piles of radioactive soil that can’t be moved into storage

gfhjgjkkl,l.jpg

Masaaki Sakai faces his home, which remains standing in the Fukushima Prefecture village of Iitate, on Feb. 15, 2017. In some spots the level of radiation exceeds 1 microsievert per hour, and Sakai has decided to have the structure demolished. (Mainichi)

FUKUSHIMA — As decontamination planned in the wake of the Fukushima nuclear disaster nears an end this fiscal year, focus is shifting to the massive amount of radioactively tainted soil that has piled up during decontamination work. But the construction of interim storage facilities that are supposed to hold this waste within Fukushima Prefecture for up to 30 years before it is finally disposed of has been delayed.

As of the end of February, only about 20 percent of the 16,000 hectares earmarked for interim storage has been acquired through land contracts. It thus appears inevitable that provisional and onsite storage that was only supposed to last for three years will drag on for a long time. The situation casts doubt on the prospects of finding a final resting place for the waste outside Fukushima Prefecture within 30 years.

Six years after the disaster at the Fukushima No. 1 Nuclear Power Plant, the Fukushima Prefecture village of Iitate remains completely evacuated. With the exception of a so-called “difficult to return zone” in the south of the village, the central government plans to lift the evacuation order upon completion of decontamination work at the end of March.

Masaaki Sakai, 39, who now resides in the city of Fukushima, has a home in the Komiya district of Iitate, right next to the village’s “difficult to return” zone. A dosimeter during a recent visit showed the area around the 60-year-old, snow-covered farmhouse stood at more than 1 microsievert per hour. The level equates to more than 5 millisieverts per year — five times the 1 millisievert exposure limit for a regular person.

Sakai points out that level of radiation is sometimes higher. “Today the level is low because there is snow,” he says. In the near future he plans to have his home pulled down, as the deadline for applying for the government to cover the cost of doing so is approaching.

“Even if I want to return to Iitate, if they say, ‘Decide now’ then the only thing I can do is decide not to return,” he murmurs.

One of the reasons behind Sakai’s decision not to return is the radioactively contaminated soil that remains in the village. Walking around the village, one can see mounds with green covers over them, concealing flexible containers that hold contaminated soil. According to the Ministry of the Environment, the amount of tainted soil stored temporarily like this, as of the end of January, totals roughly 2.4 million cubic meters for the village of Iitate alone, or enough to fill the Tokyo Dome baseball stadium twice.

So far, however, only about 6,000 cubic meters of soil have been transported to interim storage facilities, while the amount due to be transported next fiscal year stands at about 22,000 cubic meters. At this pace, under a simple calculation, it would take over 100 years to transport all of the waste to interim storage facilities.

“There’s no way I’m going to live surrounded by mountains of contaminated soil,” Sakai says.

Makeshift storage of radioactive soil in areas that have not been evacuated also looks likely to be prolonged. In areas that aren’t under evacuation orders, it is the local municipalities, not the government, that handle the decontamination work. In five municipalities including the cities of Fukushima and Koriyama, the contaminated soil left after decontamination work is mostly buried onsite.

Six years have passed since the outbreak of the Fukushima nuclear disaster, and in many cases people have asked for the waste to be removed so they can extend or rebuild their homes or resume farming activities, but the delay in building interim storage facilities means the only solution for the time being is to change the spot where the waste is buried.

It costs several hundred thousand yen to rebury waste in a single case, but until now the Ministry of the Environment has not allowed funds to be used for the reburying of such waste, on the premise that it is supposed to be stored for only a short period of time. Local bodies have still billed the central government by quietly tacking on the cost to the fee for other decontamination work, but this will become more difficult to do next fiscal year when decontamination work is completed.

In January, the Ministry of the Environment adopted a new policy of granting funds for the reburying of waste if the original location hindered the construction of a new home. An official at one local body commented that the move was a relief, but there are outstanding issues. As a rule, the government collectively bills Tokyo Electric Power Co. (TEPCO), operator of the Fukushima No. 1 Nuclear Power Plant, for the cost of decontamination work, but it is unclear whether TEPCO has to pay for the reburial of tainted soil.

Separately, decontamination work has also been carried out in prefectures besides Fukushima — extending to 57 municipalities in seven prefectures, including Tochigi and Miyagi. The amount of contaminated soil in these cases stands at about 320,000 cubic meters. In about 95 percent of cases, the soil is stored onsite. But since interim storage facilities are designed for contaminated soil from Fukushima Prefecture alone, it has not even been decided what should be done with this waste.

http://mainichi.jp/english/articles/20170309/p2a/00m/0na/019000c

SIX YEARS AFTER: Poll: At least 20 years to regain lifestyle, half of Fukushima says

uh_hjkl.jpg

Decontamination work is conducted on March 2 in Namie, Fukushima Prefecture, which will no longer be designated an evacuation zone on March 31.

 

Half of Fukushima Prefecture residents believe it will take at least another 20 years for them to return to the lives they enjoyed before the 3/11 disaster, according to a new poll.

The Asahi Shimbun and Fukushima Broadcasting Co. contacted prefectural residents on Feb. 25-26 to ask about life after the triple nuclear meltdown crisis following the 2011 Great East Japan Earthquake and tsunami. It was the seventh in the annual series of polls on the issue.

In the survey, 50 percent of respondents said “more than 20 years” when asked their outlook on the timescale to restore their previous lifestyle. Twenty-one percent said “about 20 years,” followed by 16 percent who thought “about 10 years,” and 7 percent who responded “about five years.”

In the 2013 poll, those who thought it would take more than two decades for them to regain their pre-disaster life totaled 60 percent. The numbers cannot simply be cross-referenced since 18 and 19 years olds have been included in the latest survey for the first time, but while the results suggest some improvement, they also paint a picture of many residents of the prefecture still unable to have an optimistic outlook on their future.

Thirty percent of respondents of the latest survey said there are times they feel discriminated against for being Fukushima Prefecture residents.

The central government plans to cover part of the costs on the Fukushima nuclear crisis that is estimated to rise to 21.5 trillion yen ($188 billion) by including the expenses in electricity rates on regular households.

It is a plan that has been criticized to be nothing more than a scheme to bail out Tokyo Electric Power Co., operator of the Fukushima No. 1 nuclear power plant, and 76 percent of respondents said they could not accept such a measure.

With the evacuation order for the town of Tomioka scheduled to be lifted on April 1, most residents of the prefecture who were displaced from their homes due to the nuclear disaster will be able to go back, excluding those who lived in areas still designated as “difficult-to-return zones.”

But opinions over the issue varied among respondents, suggesting skepticism over decontamination work and concerns over radiation still linger among many residents.

When asked about the timing of lifting the evacuation order, the most popular answer, from 40 percent, was that it was an appropriate decision. However, 19 percent said it was “too soon,” while 22 percent said the order “should not be lifted in the first place.” Nine percent said it was “too late.”

Respondents were also divided over their evaluation of decontamination work in the prefecture conducted by the central and local governments.

Those who applauded the effort, which comprised the 3 percent who “highly” praised it and the 48 percent who “somewhat” did, was at just over half. But an almost equal amount of respondents, 46 percent, expressed criticism, with 39 percent saying they “did not really” think enough was being done and 7 percent saying they were not at all satisfied.

When asked whether they had any concerns of the effects of radiation on themselves or their family, most residents, at 63 percent, said yes. This comprised the 19 percent who said they were very concerned and the 44 percent who responded they were worried to some extent.

Those who were more critical of the decontamination efforts, as well as respondents who expressed concern over the effects of radiation, tended to reply that the evacuation order “should not be lifted in the first place.”

Regarding “difficult-to-return zones,” the central government plans to concentrate their decontamination work on specific areas to allow residents to live there.

Respondents were divided over this decision as well, with 43 percent for and 42 percent against.

However, when asked about how the central government and TEPCO were handling the buildup of contaminated groundwater at the crippled nuclear plant, the majority of respondents expressed criticism. A total of 71 percent said they were dissatisfied, compared with the 14 percent who thought enough was being done.

The poll targeted eligible voters aged 18 or older living in the prefecture. Valid responses were received from 934 individuals out of the 1,739 randomly generated landline numbers contacted, or 54 percent.

http://www.asahi.com/ajw/articles/AJ201703030048.htm