Fukushima dome roof takes shape, but radiation remains high — The Asahi Shimbun

” High radiation levels are still limiting recovery work at the Fukushima No. 1 nuclear plant, a stark reality that reporters saw firsthand when they observed efforts to remove risk factors there.

Media representatives were invited into the plant in early December to see construction work, with the building of a domed roof over the No. 3 reactor building as the main focus.

However, they were only allowed to stay on top of the roof for 20 minutes due to high radiation levels.

The roof is being put together directly above the storage pool for spent fuel. The dome is designed to prevent the spewing of radioactive materials when the fuel is actually removed from the pool.

The original roof of the No. 3 reactor building was severely damaged by a hydrogen explosion in the days following the March 11, 2011, Great East Japan Earthquake and tsunami, which led to the crippling of the Fukushima No. 1 plant.

Spent fuel still remains in the storage pools located on the top floors of the No. 1 to No. 3 reactor buildings.

Plans call for removing the spent fuel first from the No. 3 reactor building.

Although the dome will help prevent the spread of radioactive materials, building parts and other debris as well as some equipment have still not been completely removed from the storage pool, which holds 566 fuel rods.

The collapsed roof and walls were removed to allow for the construction of the domed roof, which began in the summer. The domed roof is about 17 meters high, and a crane was also installed under it in November.

Plans call for the removal of the spent fuel from the No. 3 building to begin in the middle of the next fiscal year.

Internal radiation exposure levels were measured before media representatives headed to the No. 3 reactor building. They were also required to don protective clothing as well as a partial face mask covering the mouth and nose from about 100 meters from the building.

Radiation levels close to the building were 0.1 millisieverts per hour.

An elevator installed into the scaffolding next to the reactor building took the media representatives to the roof, which had been covered with metal plates.

The so-called operating floor looked like any other newly constructed building roof, a sharp contrast to the twisted metal parts that covered the building shortly after the nuclear accident.

Tokyo Electric Power Co., the plant’s operator, captured video footage from within the reactors for the first time in July. Debris that appears to be melted nuclear fuel was found in various parts of the containment vessel.

To the south of the No. 3 reactor building stands the No. 4 reactor building, from where all the spent nuclear fuel has been removed.

To the north is the No. 2 reactor building, which avoided a hydrogen explosion. Beyond the building, cranes and other large equipment are working in preparation for the removal of debris from the No. 1 reactor building.

TEPCO officials cautioned media representatives about standing too long right next to the storage pool, which could be seen located about six meters below the roof. Debris was found within the pool while insulating material floated on the pool surface.

The radiation level near the pool was 0.68 millisieverts per hour. While that was a major improvement from the 800 millisieverts per hour recorded in the immediate aftermath of the nuclear accident close to seven years ago, it was still too high to allow for a stay of longer than 20 minutes. ”

by Chikako Kawahara, The Asahi Shimbun

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Plans to remove nuclear fuel at Fukushima delayed again — Reuters via Channel NewsAsia

” A plan to remove spent nuclear fuel from Tokyo Electric Power Co Holdings Inc’s Fukushima Daiichi nuclear plant hit by the March 2011 tsunami has been postponed again due to delays in preparation, the Nikkei business daily reported on Thursday.

Work is now set to begin in fiscal 2018 at the earliest, the Nikkei said.

Removal of the spent fuel from the No. 3 reactor was originally scheduled in the first half of fiscal 2015, and later revised to fiscal 2017 due to high levels of radioactivity around the facilities, the Japanese business daily reported.

The timeline has been changed again as it was taking longer than expected to decontaminate buildings and clean up debris, the news agency reported.

The report comes a few months after the Japanese government said in October the cost of cleaning up the Fukushima plant may rise to several billion dollars a year, adding that it would look into a possible separation of the nuclear business from the utility. ”

Reporting by Krishna V Kurup in Bengaluru, editing by Shounak Dasgupta, REUTERS

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For 6,000, the daily bus ride takes them to Fukushima plant — The Asahi Shimbun

” NARAHA, Fukushima Prefecture–Despite the predawn hour, few people are sleeping on a bus that steadily makes its way north on National Route 6.

Some passengers are planning for the work ahead. One is looking forward to chatting with his colleagues. And a few wonder if today will be the day when their annual radiation doses reach the safety limit.

Every day, buses like this take 6,000 workers to the Fukushima No. 1 nuclear power plant. And every day, the same buses take the exhausted and mostly sleeping workers back to their base at the Japan Football Village (J-Village) in Naraha.

Although the Fukushima plant is still decades away from being decommissioned, without this daily routine of the workers who toil amid an invisible danger, the situation at the site would be much more difficult.

407 Daily Bus Rides

One of them, the 49-year-old leader of a group of metal workers from Iwaki, Fukushima Prefecture, has been working at nuclear plants, including the Kashiwazaki-Kariwa power station in Niigata Prefecture, for nearly 20 years.

He was at the Fukushima No. 1 nuclear plant when the Great East Japan Earthquake and tsunami triggered the triple meltdown there in March 2011.

“Nobody can get close to the area where the melted nuclear fuel remains due to high radiation doses,” the man said. “Even if we could approach the area, we would have no way out if something happens. The situation is harsh.”

Those metal workers install tanks for the contaminated water that keeps accumulating at the plant.

Although there are plenty of empty seats, the young workers sit in front and the older workers take the back seats.

Thousands of workers are staying at temporary dormitories set up in J-Village, a soccer training complex.

Tokyo Electric Power Company Holdings Inc., operator of the nuclear plant, hired a local bus company to transport the workers to the plant because securing parking areas near the site has been difficult since the 2011 disaster.

The company provides 407 services a day to and from the plant. Each trip takes about 30 minutes.

The first shuttle bus departs from J-Village at 3:30 a.m., while the last bus leaves the Fukushima plant at 9:45 p.m.

In mid-November amid torrential rain, one bus picked up a man taking shelter under the eaves of a bus stop.

He said he is in charge of managing data related to radiation doses of fittings and other equipment at the plant.

“We have many different types of work here,” the man proudly said.

Also on the way to the nuclear plant, a 53-year-old employee of a security company was thinking about personnel distribution.

Like other workers there, security guards must be replaced when their annual radiation doses reach a certain level set by the government.

He said he has difficulties making ends meet with a limited number of guards who have knowledge about radiation.

Suddenly, the man’s cellphone rings, and the caller orders the deployment of additional security guards to the plant.

A 52-year-old TEPCO employee was on the way to the nearby Fukushima No. 2 nuclear power plant to provide a safety training program for workers, many of whom are victims of the triple disaster.

“I want to convey to workers how precious their lives are and how important safety is in a way that doesn’t make me sound hypocritical,” the employee said.

The triple meltdown has been called a “man-made disaster” caused by the failure of both TEPCO’s management and the government’s regulatory authorities.

The TEPCO employee will use props, such as a ladder, and pretend to be a worker to explain dangerous cases at the No. 1 plant.

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On the trip back to J-Village, a different atmosphere exists on the bus.

Although dazzling sunlight shines through the windows and stunning views of the ocean are available, most of the workers are fast asleep in their wrinkled uniforms.

“Few people stay awake. I don’t even switch on the radio. They must be tired after their work,” said Nobuyuki Kimura, 52, who has driven the shuttle bus for one-and-a-half years.

In Kimura’s bus that departed the plant at 2:30 p.m., all 50 seats and some of the auxiliary seats were filled. The few passengers who stayed awake remained quiet.

By early evening, fewer workers boarded the bus at the plant.

Window seats at the back of the bus are desirable on all rides because they have an enough room for the seats to recline, allowing passengers to cross their legs.

A 21-year-old worker from Iwaki went for a window seat at the back after standing at the front of a line waiting for the bus.

“I can relax sitting here. This is the premium seat,” said the man who collects waste materials, such as boots and socks, at the site.

Although he works in protective gear in an area with high radiation levels, he said he has never thought about quitting his job.

He said he became fed up with school as a junior high school student, and did not bother going to senior high school.

At the age of 18, he joined his current company, and his first assignment was at the Fukushima No. 1 plant.

“I became acquaintances with more and more people. It’s fun to speak with people at work,” he said.

Through his work at the nuclear plant, his weight has dropped from 115 kilograms to 93 kg.

Thirty to 40 years are needed to decommission the Fukushima No. 1 plant, according to the mid- and-long-term roadmap compiled by the government and TEPCO.

To reduce the groundwater flowing into the buildings housing the No. 1 to No. 4 reactors, TEPCO installed coolant pipes this year to create an underground frozen soil wall to divert the water into the ocean.

TEPCO announced in October that the ice wall on the sea side was nearly frozen, but groundwater is believed to be seeping through it.

The utility plans to start removing spent fuel from the No. 3 reactor building in fiscal 2017. It also has plans to begin the daunting task of removing the melted fuel from the No. 1 to No. 3 reactor containment vessels in 2021.

However, extremely high radiation levels have prevented workers from approaching and understanding the condition of the melted fuel. The removal method has yet to be decided.

The estimated cost of work for decommissioning and dealing with the contaminated water has ballooned to 8 trillion yen ($68.1 billion). ”

by Aya Nagatani

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Tepco turns to ‘Toy Story’ claw to inspire Fukushima cleanup — Bloomberg Business; IEEE Spectrum; MIT Technology Review

Read a similar articles by IEEE Spectrum and the MIT Technology Review.

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Bloomberg Business:

” Tokyo Electric Power Co. and partner Toshiba Corp. have a new twist in mind to pluck out the debris and spent fuel in one of the buildings at the wrecked Fukushima atomic plant north of Tokyo.

They’ll use a collection of robotic arms and pulleys weighing nearly 200 metric tons that resemble the claw game featured in the Pixar-animated movie “Toy Story” when in motion.

The system, which was invented to deal with the Fukushima aftermath and has never been used at a nuclear power plant, is the latest example of the advanced technology Tokyo Electric and partners will need to tap over the course of the site’s cleanup.

Toshiba designed the new system to be controlled offsite, allowing employees to use joysticks to remotely grab debris, cut wires and move fuel.

“With the current radiation levels, it would be impossible to send people into the building to do any cleanup work,” Isao Shirai, an official at Tokyo Electric, told reporters Monday in Yokohama where the partners demonstrated the retrieval system.

Installation of the Toshiba-designed equipment will begin this year, with an eye to start up in fiscal 2017. The removal process is expected to take two years, according to Tokyo Electric’s Shirai. ”

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Editorial: New technology to help resolve Fukushima nuclear crisis needs gov’t backing — The Mainichi; South China Morning Post

” The Japanese government has once again revised the work schedule for decommissioning reactors at the triple-meltdown-stricken Fukushima No. 1 nuclear plant. The last major change was in June 2013, and this one pushes back the removal of spent fuel rods from the fuel pools of the No. 1-3 reactors by as much as three years. The delay is due to unexpected difficulties preventing the escape of airborne radioactive contaminants during decontamination and wreckage clearing work.
Decommissioning reactors at the heart of one of the world’s worst nuclear disasters is of course bound to be extremely difficult, and this reality is coming into sharp relief.

Progress on dismantling the Fukushima reactors has a direct bearing on both overall regional disaster recovery and when local residents will be able to finally return home. As such, we call on both the government and plant operator Tokyo Electric Power Co. to develop a reactor decommissioning strategy with a solid strategic foundation, and to thoroughly release information on the process.
The latest revisions to the decommissioning work schedule were based on the basic principle of putting the safety of locals and plant workers first. The first version of the work schedule was obsessed with speed. The result was a rash of worker injuries and deaths and other problems that ended up causing progress to be delayed. Rather than making speed top priority, it’s more important to carefully and surely reduce the various risks related to the Fukushima plant.

The jobs with the highest priority under the work plan’s latest iteration are the recovery of nuclear fuel rods from the fuel pools, and dealing with the vast quantities of radioactively contaminated water produced at the plant. Though these tasks are certainly important, the most difficult hurdle in the decommissioning process will be extracting the melted fuel from inside the stricken reactor vessels. Under the new schedule, this is set to start on just one of the reactors sometime in the year 2021.

That’s some six years away, but the path from here to there remains foggy at best. First of all, no one knows for sure exactly what state the fuel is in or even where it is in the reactor housings.

The method for getting the fuel out is also up in the air. At first, planners thought it best to fill the reactor vessels with water to suppress the intense radiation when the operation began. This fell by the wayside, however, when it turned out to be difficult to identify damaged spots on the reactor vessels and stop water from escaping. Now, an in-air removal method is being considered, though entirely new equipment will need to be developed to perform the operation in the highly radioactive environment while at the same time preventing contaminants from getting airborne.

There are a number of research institutes and universities across Japan that are receiving government support to invent the technology needed for this reactor decommissioning work. The “control tower” for these efforts is the Nuclear Damage Compensation and Decommissioning Facilitation Corp. (NDF), created by the government in August last year. The corporation is tasked with overseeing each project from basic research through to practical application, and to optimize the development process.

The NDF, however, has just 35 or so technical staff. It’s an open question whether the NDF can exercise effective oversight for such a wide program with so few people. The government is trying to enhance the corporation’s functions, but there have been no concrete measures forthcoming so far. At this rate, might the 30-40 year target to decommission the Fukushima reactors come under serious pressure?

Prime Minister Shinzo Abe has said more than once that “the national government stands on the front lines” of the efforts to deal with the decommissioning work. Then more than ever, the government must create a system to provide full and complete support for the technology research and development projects needed to finally bring the nuclear crisis to an end. ”

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Also read a similar article by the South China Morning Post: “Scale of Fukushima clean-up revealed as decommissioning ‘road map’ is revised

Fukushima decommissioning schedule revised to delay spent fuel removal — The Japan Times

” With the decommissioning of Fukushima No. 1 proving harder than expected, planners have pushed back plans to remove spent nuclear fuel from the cooling pools perched above the damaged reactors by a few years.

The decision was made Friday by the government and Tokyo Electric Power Co., which runs the tsunami-hit complex.

The spent fuel rod assemblies must be removed from the pools above reactor Nos. 1, 2 and 3 before any attempt can be made to extract the fuel that melted inside the reactors themselves.

But the delay will not impact the overall cleanup timeline for the plant, which spans 30 to 40 years, the government and Tepco said.

The first revision to the decommissioning road map in two years was made after it was decided that too much priority had been placed on speed. This would have heaped excessive pressure on workers tasked with operating in a highly radioactive environment. The road map was first crafted in December 2011.

According to the revised road map, the removal of fuel assemblies from the No. 3 cooling pool will be delayed until fiscal 2017, as it is already behind schedule. The work was expected to be finished in the first half of fiscal 2015, which ends next March.

Work to extract fuel assemblies from the pools on units 1 and 2 is now expected to begin in fiscal 2020, instead of fiscal 2017.

The subsequent extraction of the melted fuel — the most challenging part of the process — is expected to start in 2021, but the government and Tepco have not yet figured out how to do it. They are aiming to settle on a single approach in fiscal 2018.

The revised road map also aims to reduce the amount of groundwater seeping into the structurally damaged plant to less than 100 tons per day in fiscal 2016, instead of 300 tons. The influx of groundwater has become its own crisis by mingling with the highly radioactive water generated in the daily process of cooling the leaking reactors. And all of it must be stored on site until it can be cleaned.

The most important progress made at the plant so far has been the removal of all the fuel assemblies that had been stored in the cooling pool above the No. 4 reactor, which suffered a hydrogen explosion but avoided meltdown.

The revision also said the government and Tepco will begin discussions in the first half of 2016 on how to dispose of water tainted with tritium. The filters currently available can remove all radioactive isotopes from large volumes of water with the exception of tritium, a common byproduct at nuclear plants.

The International Atomic Energy Agency and the Nuclear Regulation Authority have suggested such water be dumped into the ocean rather than be kept in tanks, to reduce the risk of accidents, but Tepco remains undecided on this given strong local opposition to the proposal, especially by fishermen. ”

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Also read The Japan Times article, “Start of reactor fuel removal at crippled Fukushima No. 1 plant may be delayed up to three years.”