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TEPCO conducts test to halt water injection into crippled reactor

13 may 2019.jpgThis March 11, 2019 photo, taken from Futaba, Fukushima Prefecture, shows the Fukushima Daiichi nuclear power plant, which was struck by the 2011 earthquake-tsunami disaster in northeastern Japan and is in the process of being decommissioned.

May 13, 2019
FUKUSHIMA, Japan (Kyodo) — The operator of the Fukushima Daiichi nuclear power plant on Monday conducted a test to temporarily halt the water being injected into one of the reactors that suffered a core meltdown in the wake of the 2011 accident
Through the test, which is the first of its kind, Tokyo Electric Power Company Holdings Inc. plans to obtain data on how the temperature inside the No. 2 reactor could rise in the event of an emergency and use the input to update its response.
More than eight years on from the start of what has become one of the world’s worst nuclear crises, TEPCO continues to pour water inside the Nos. 1 to 3 reactors to keep the melted fuel debris inside them cool.
At 10:40 a.m. Monday, TEPCO completely halted the water injection into the No. 2 unit, which usually receives around 3 tons of coolant per hour.
The temperature at the bottom of the reactor pressure vessel, a container that is supposed to hold the fuel, stood at about 24.5 C and TEPCO expects the reading to rise by up to 4 C following the 7-hour test.
Hit by a magnitude 9.0 earthquake and ensuing tsunami on March 11, 2011, the Fukushima nuclear complex lost nearly all its power sources and consequently the ability to cool the reactors and spent fuel pools at the Nos. 1 to 4 units.
The conditions of the reactors are now kept relatively stable through recovery efforts, but a massive amount of contaminated water has accumulated at the plant as a result.
https://mainichi.jp/english/articles/20190513/p2g/00m/0dm/071000c

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May 15, 2019 Posted by | fukushima 2019 | , , | Leave a comment

Fukushima plant radioactive water could be stored in tanks long term: gov’t source

Heading toward 1.37 million tons of strontium-90 tea, enough to give a 500ml portion to 2.74 billion people
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May 13, 2019
The Japanese administration is considering keeping the enormous and still growing volume of radioactively contaminated water at the disaster-stricken Fukushima Daiichi nuclear plant in storage tanks for the long term, a source close to the government has told the Mainichi Shimbun.
Previously, five options to deal with the contaminated water were being compared: releasing it into the ocean; piping it into a deep stratum of the Earth’s crust; releasing it into the atmosphere as steam; encasing it in cement and burying it; and using electrolysis to hydrogenate tritium — a relatively low-impact radioactive element not filtered out with plant operator Tokyo Electric Power Co. (TEPCO)’s current decontamination systems — in the water before releasing it into the air.
However, strontium 90 — a radioactive element that can accumulate in the bones — was discovered in treated water in government maximum-busting concentrations just before August 2018 public hearings on the contaminated water problem. The revelation “completely destroyed the premise for discussions,” the Mainichi source said, and public worries about releasing the water into the environment prompted the government to reconsider.
As a result, a Ministry of Economy, Trade and Industry expert committee on the contaminated water issue set to meet in June will add long-term tank storage to the existing five options.
According to the government source, the administration will take the expert committee’s opinions into account when it makes a final decision on the water problem. However, views in the prime minister’s office are apparently split. Furthermore, the government is worried that taking any decision ahead of the 2020 Tokyo Games could invite increased attention on the problem and risks the spread of harmful rumors, making it very difficult to project which method will be chosen.
Any of the options is expected to take about two years to implement, a senior industry ministry official said.
Meanwhile, Nuclear Regulation Authority (NRA) Chairman Toyoshi Fuketa warned at a March news conference that “the time when a decision must be made (on how to deal with the contaminated water) is very close indeed.”
There is already over 1 million metric tons of contaminated water stored on-site at the Fukushima Daiichi plant, while existing plans will see total capacity max out at 1.37 million tons in 2020. At the current rate of increase, all the 10-meter-tall tanks will be full in four to five years. It is thought that the government will look into processing the water in small quantities as the total volume nears capacity, beginning with the most lightly contaminated.
However, “from a scientific and technical standpoint, the only choice is to dilute it and release it into the ocean,” Fuketa said at the March news conference. The industry ministry’s panel of experts has released figures showing this is also the fastest and lowest-cost option.
The water volume continues to increase due to ground water flowing into the fractured reactor buildings, and the need to keep pumping more water into the shattered reactor cores to cool the nuclear fuel debris inside. Just after the March 2011 triple-meltdown at the plant triggered by the Great East Japan Earthquake and tsunami, the amount of groundwater flowing into the reactor buildings was around 400 tons daily. A subterranean ice wall and other measures have cut this by about half, but eliminating it entirely is impossible.
It is expected to take until 2051 to finish decommissioning the Fukushima Daiichi plant, including processing the contaminated water.
https://mainichi.jp/english/articles/20190513/p2a/00m/0na/006000c?fbclid=IwAR073VgJRSeZObQZWxnufaW7bQVUNFuGKIoJAdnxFOI-XzjQhvJa2pvqQQY

May 15, 2019 Posted by | fukushima 2019 | , , | Leave a comment

TEPCO to slice dangerous chimney at Fukushima plant

chimney reactors 1 & 2 10 may 2019.jpgA chimney for both the No. 1 and No. 2 reactors remains unrepaired at the Fukushima No. 1 nuclear power plant. At left is the No. 1 reactor building.

May 10, 2019
Tokyo Electric Power Co. plans to start work on May 20 to dismantle a 120-meter-tall, highly contaminated chimney that could collapse at the crippled Fukushima No. 1 nuclear power plant.
It will be the first highly radiated facility at the plant to be taken apart, the company said May 9.
The stack, with a diameter of 3.2 meters, was used for both the No. 1 and No. 2 reactors. TEPCO plans to remove the upper half of the chimney within this year to prevent the structure from collapsing.
The dismantling work will be conducted by remote control because the radiation level around the base of the chimney is the highest among all outdoor areas of the plant. Exposure to radiation at the base can cause death in several hours.
After the Great East Japan Earthquake and tsunami struck in March 2011, pressure increased in the containment vessel of the No. 1 reactor. Vapors with radioactive substances were sent through the chimney to the outside.
TEPCO also found fractures in steel poles supporting the chimney. The damage was likely caused by a hydrogen explosion at the No. 1 reactor building when the nuclear disaster was unfolding.
Since then, the chimney has been left unrepaired because of the high radiation levels.
Immediately after the nuclear accident, a radiation level exceeding 10 sieverts per hour was observed around the base of the chimney. In a survey conducted in 2015, a radiation level of 2 sieverts per hour was detected there.
TEPCO will use a large crane that will hold special equipment to cut the chimney in round slices from the top.
The company set up a remote control room in a large remodeled bus about 200 meters from the chimney. Workers will operate the special cutting equipment while watching footage from 160 video cameras.
http://www.asahi.com/ajw/articles/AJ201905100045.html

May 15, 2019 Posted by | fukushima 2019 | , , , | Leave a comment

New Discovery At Fukushima Unit 3 Provides Clues To Meltdown Severity, Environmental Releases

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May 3, 2019
TEPCO recently published a video of the work to remove spent fuel from the unit 3 fuel pool. In this video was an unexpected finding with serious implications.
In the video of the fuel assembly removal from a fuel rack inside the spent fuel pool, was a tell tale sign of something significant. Prior to the effort to remove fuel from the pool, the pool underwent significant cleaning work. This included removing most of the debris that fell into the pool along with use of a vacuum to remove small pieces of broken concrete and dust.
What remains adhered to the side of the fuel rack appears to be the same thick white substances found inside the reactor containment of unit 3 and in the pedestal below the reactor vessel. These substances also have the same appearance as those inside containment. They are stuck to both vertical and horizontal surfaces as if they splattered then stuck to where they landed. What these may be and how they managed to end up on the fuel racks is explained further in this report.
Read more:
Simply Info

New Discovery At Fukushima Unit 3 Provides Clues To Meltdown Severity, Environmental Releases

May 8, 2019 Posted by | fukushima 2019 | , , | Leave a comment

Japan needs thousands of foreign workers to decommission Fukushima plant, prompting backlash from anti-nuke campaigners and rights activists

Activists are not convinced working at the site is safe for anyone and they fear foreign workers will feel ‘pressured’ to ignore risks if jobs are at risk
Towns and villages around the plant are still out of bounds because radiation levels are dangerously high
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Workers move waste containing radiated soil, leaves and debris from the decontamination operation at a storage site in Naraha town.
26 Apr, 2019
Anti-nuclear campaigners have teamed up with human rights activists in Japan to condemn plans by the operator of the crippled Fukushima Daiichi nuclear plant to hire foreign workers to help decommission the facility.
Tokyo Electric Power Co (TEPCO) has announced it will take advantage of the government’s new working visa scheme, which was introduced on April 1 and permits thousands of foreign workers to come to Japan to meet soaring demand for labourers. The company has informed subcontractors overseas nationals will be eligible to work cleaning up the site and providing food services.
About 4,000 people work at the plant each day as experts attempt to decommission three reactors that melted down in the aftermath of the March 2011 Great East Japan Earthquake and the huge tsunami it triggered. Towns and villages around the plant are still out of bounds because radiation levels are dangerously high.
TEPCO has stated foreign workers employed at the site must have Japanese language skills sufficient for them to understand instructions and the risks they face. Workers will also be required to carry dosimeters to monitor their exposure to radiation.
Activists are far from convinced working at the site is safe for anyone and they fear foreign workers will feel “pressured” to ignore the risks if their jobs are at risk.
“We are strongly opposed to the plan because we have already seen that workers at the plant are being exposed to high levels of radiation and there have been numerous breaches of labour standards regulations,” said Hajime Matsukubo, secretary general of the Tokyo-based Citizens’ Nuclear Information Centre. “Conditions for foreign workers at many companies across Japan are already bad but it will almost certainly be worse if they are required to work decontaminating a nuclear accident site.”
Companies are desperately short of labourers, in part because of the construction work connected to Tokyo hosting the 2020 Olympic Games, while TEPCO is further hampered because any worker who has been exposed to 50 millisieverts of radiation in a single year or 100 millisieverts over five years is not permitted to remain at the plant. Those limits mean the company must find labourers from a shrinking pool.
In February, the Tokyo branch of Human Rights Now submitted a statement to the UN Human Rights Council in Geneva demanding action be taken to help and protect people with homes near the plant and workers at the site.
“It has been reported that vulnerable people have been illegally deceived by decontamination contractors into conducting decontamination work without their informed consent, threatening their lives, including asylum seekers under false promises and homeless people working below minimum wage,” the statement said. “Much clean-up depends on inexperienced subcontractors with little scrutiny as the government rushes decontamination for the Olympic Games.”
Cade Moseley, an official of the organisation, said there are “very clear, very definite concerns”.
“There is evidence that foreign workers in Japan have already felt under pressure to do work that is unsafe and where they do not fully understand the risks involved simply because they are worried they will lose their working visas if they refuse,” he said.
In an editorial published on Wednesday, the Mainichi newspaper also raised concerns about the use of semi-skilled foreign labourers at the site.
“There is a real risk of radiation exposure at the Daiichi plant and the terminology used on-site is highly technical, making for a difficult environment,” the paper said. “TEPCO and its partners must not treat the new foreign worker system as an employee pool that they can simply dip into.”
The paper pointed out that it may be difficult to accurately determine foreign employees’ radiation levels if they have been working in the nuclear industry before coming to Japan, while they may also confront problems in the event of an accident and they need to apply for workers’ accident compensation. TEPCO has played down the concerns.
“About 4,000 Japanese workers are already working on the decommissioning and clean-up work at Fukushima Dai-ichi,” the company said. “The amendment to the regulations on workers from overseas is a measure that creates more employment opportunities, including for foreign nationals with specific skills.
“In March, TEPCO explained the new regulations to its contractor companies involved in the clean-up work at Fukushima Dai-ichi and we have also confirmed that those companies will be in compliance with the regulations covering the safety of workers.”

May 1, 2019 Posted by | fukushima 2019 | , | Leave a comment

Safety, language measures needed for foreigners to work at Fukushima plant

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April 24, 2019
Tokyo Electric Power Co. (TEPCO) is preparing to bring in
foreign workers with special technical skills to join decommissioning work on the disaster-stricken Fukushima Daiichi nuclear plant.
At present, an average of 4,000 employees of TEPCO and cooperating firms work at the facility every day. Laws and regulations stipulate that workers’ radiation exposure must be limited to 50 millisieverts in a single year, and 100 millisieverts over five years. No one is allowed to stay at the plant once they hit one of these caps, so waves of new employees must be brought in to maintain worker numbers.
Decommissioning the Daiichi plant, which suffered a triple core meltdown in the wake of the March 2011 Great East Japan Earthquake and tsunami, is expected to take 30 to 40 years. Whether the companies involved can sustain sufficient staffing levels will be one factor that determines the success or failure of the project.
When it comes to tapping foreign labor to make up the required numbers, the Justice Ministry — which has jurisdiction over Japan’s immigration system — has already declined to approve sending foreign technical intern trainees to work at the plant. One of the core tenets of the foreign technical trainee program is that the job placements must provide the trainees with skills they can use in their home countries, and working to decommission a devastated nuclear plant did not fit the bill.
TEPCO is now turning its eyes to foreign workers with Category 1 work visas, one of the new residency statuses launched on April 1 and aimed at those with certain skills and experience. Technical trainees with three years’ experience in Japan can obtain this visa without a skills exam.
However, there is a real risk of radiation exposure at the Daiichi plant, and the terminology used on-site is highly technical, making for a difficult environment. TEPCO and its partners must not treat the new foreign worker system as an employee pool they can simply dip into.
The workers’ Japanese level is particularly a cause for worry. To obtain a Category 1 visa, applicants must speak Japanese at only a “daily conversational” level. However, anyone working at the Daiichi site must understand a slew of technical terms related to radiation and other facets of the decommissioning process, meaning a very high level of Japanese is absolutely indispensable. If foreign employees begin working there without having learned the necessary terminology, we believe there is a real risk they could be ordered to do jobs that exposed them to radiation.
TEPCO has said it is up to its project partners whether they employ Category 1 foreign workers. In fact, the majority of people at Fukushima Daiichi are employed by one of the firms that make up the layers upon layers of subcontractors working on the decommissioning. Nevertheless, as the company heading the project, TECPO has a responsibility to oversee the conditions of every worker, right down to the bottom of the pyramid.
Furthermore, if a foreign worker has been exposed to radiation overseas, that dose must be added to their sievert count at the plant. However, it is up to the worker to report any previous radiation exposure, which can make it difficult to properly track and manage their doses.
If a worker develops a radiation-related illness after returning to their home country, will they be able to smoothly apply for workers’ accident compensation? This is also a serious worry.
If Japan is to accept foreign workers to help decommission the Fukushima Daiichi plant, it is absolutely essential to create the appropriate environment, including measures to boost their Japanese skills and strengthen radiation exposure management.

May 1, 2019 Posted by | fukushima 2019 | , | Leave a comment

TEPCO transfers some fuel from Fukushima plant No. 3 unit pool

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This photo taken from a Kyodo News helicopter shows a trailer (bottom center) thought to be carrying nuclear fuel from one of the reactor buildings at the Fukushima Daiichi Nuclear Power Plant.
April 23, 2019
FUKUSHIMA, Japan(Kyodo) — The operator of the crippled Fukushima Daiichi Nuclear Power Plant said Tuesday it has transferred some nuclear fuel from one of the reactor buildings damaged by hydrogen explosions in the 2011 disaster to another location for safer storage and management.
It was the first removal of such fuel from storage pools of the Nos. 1 to 3 units, which suffered meltdowns after losing power in the crisis triggered by a massive earthquake and tsunami.
Seven unspent fuel rod assemblies were transferred Tuesday to a common pool about 100 meters away, according to Tokyo Electric Power Company Holdings Inc.
The transfer of nuclear fuel, which emits high levels of radiation, from the No. 3 unit pool is expected to lower the risk of the decommissioning work. The utility began the process of removing fuel there on April 15.
At around 11:15 a.m. Tuesday, a trailer began relocating the fuel assemblies, placed in a cylinder-shaped cask, to the common pool. The task was completed in about 20 minutes, carried out by about a dozen workers donning protective gear.
Since the common pool undergoes regular checkups required by law, the fuel transfer will be suspended possibly until July, the operator said.
TEPCO aims to transfer all of the remaining 559 spent and unspent fuel assemblies in the No. 3 unit storage pool to the common pool by March 2021.
The fuel removal at the No. 3 unit was originally scheduled to start in late 2014, but was pushed back multiple times as high levels of radiation, among other factors, caused delays in preparation of fuel transfer.
In fiscal 2023, the utility aims to start the task of removing fuel at the storage pools of the Nos. 1-2 units and has been assessing their surroundings.
Even if the fuel removal work progresses smoothly, TEPCO still faces the biggest challenge involved in the decommissioning of the crippled plant — retrieval of melted fuel that has dripped down in the containment vessels — at the Nos. 1-3 units.

April 23, 2019 Posted by | fukushima 2019 | , , , | Leave a comment

Ministry limits foreigners doing Fukushima cleanup

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April 19, 2019
Japanese Justice Minister Takashi Yamashita has outlined a restriction pertaining to the country’s new visa program. He said foreign nationals won’t be allowed to work in Japan if their main task is to do decontamination work at the crippled Fukushima Daiichi nuclear power plant.
 
Yamashita’s remark on Friday follows the plant operator’s statement that it will accept foreign workers hired under the new visa program to help decommission the facility.
 
Tokyo Electric Power Company says that construction, industrial machinery and automobile maintenance will be relevant to the decommissioning. The utility told the contractors to make sure they hire foreign workers legally.
 
TEPCO also says it’s not aware of a shortage of workers in the decommissioning process, but that it is up to the contractors to decide whether to hire foreigners under the new visa category.
 
Yamashita said that the Justice Ministry and other relevant ministries will ensure that foreigners in the program are eligible for the jobs they are hired to do.
 
Yamashita said foreigners coming to work in the construction sector must not be hired if their main job is decontamination work.
 
Chief Cabinet Secretary Yoshihide Suga said the industry ministry will supervise TEPCO to make sure the utility’s operations are legal and that the plant’s reactors are decommissioned safely and stably.
 
A revised immigration law that took effect on April 1 allows foreign nationals with certain vocational skills to work in a range of sectors under a new visa category.
 

April 23, 2019 Posted by | fukushima 2019 | , | Leave a comment

TEPCO plans to use new foreign workers at Fukushima plant

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Rows of storage tanks hold radiation-contaminated water on the grounds of the Fukushima No. 1 nuclear power plant.
April 18, 2019
Tokyo Electric Power Co. plans to use the new visa program to deploy foreign workers to its crippled Fukushima No. 1 nuclear plant, sparking concerns that language barriers could cause safety hazards and accidents.
The specified skills visa program started in April to alleviate labor shortages in 14 different industrial sectors. TEPCO says it has long lacked enough workers for decommissioning work at the Fukushima nuclear plant.
At a March 28 meeting, the utility explained its plan to hire foreign workers to dozens of construction and other companies that have been contracted for decommissioning work.
TEPCO officials asked the companies to be aware that workers sent to radiation monitoring zones must wear dosimeters and receive special education about the dangers they will face.
The new work visa program requires the foreign workers to have a minimum level of Japanese language ability needed for daily life.
But TEPCO officials reminded the company representatives that Japanese language skills would be even more important at the Fukushima plant because of the need to accurately understand radiation levels and follow instructions by superiors and colleagues regarding work safety.
TEPCO officials said they would ask the contracting companies to check on the Japanese language skills of prospective foreign workers.
But at least one construction company has already decided not to hire any foreign workers.
“The work rules at the No. 1 plant are very complicated,” said a construction company employee who has worked at the Fukushima plant. “I am also worried about whether thorough education can be conducted on radiation matters. It would be frightening if an accident occurred due to a failure of communication.”
According to TEPCO officials, an average of about 4,000 people work at the nuclear plant each day, mostly in zones where radiation levels must be constantly monitored.
To stay within the legal limits on exposure levels, workers often have to be replaced, leading to difficulties for TEPCO in gathering the needed number of workers.
Between April 2018 and February this year, 11,109 people worked at the Fukushima plant. Of that number, 763 were found to have levels of radiation exposure between 10 and 20 millisieverts, while 888 had levels between 5 and 10 millisieverts.
The legal limit for radiation exposure for workers at nuclear plants is 50 millisieverts a year, and 100 millisieverts over a five-year period.
The Justice Ministry has disciplined companies that used technical intern trainees for decontamination work without adequately informing them of the dangers. The ministry has also clearly stated that such trainees are prohibited from doing decommissioning work at the Fukushima plant.
However, Justice Ministry officials told TEPCO that foreigners with the new visa status could work alongside Japanese staff at the nuclear plant.
Although their numbers are small, foreign workers and engineers have been accepted at the Fukushima plant. As of February, 29 foreigners had been registered as workers engaged in jobs that expose them to radiation.
A construction company official said such foreign workers were hired after their Japanese language ability was confirmed.
But concerns remains on whether the new foreign workers will be able to properly understand how much radiation exposure they have experienced.
“Even Japanese workers are not sure about how to apply for workers’ compensation due to radiation exposure,” said Minoru Ikeda, 66, who has published a book about his experiences in decommissioning work at the Fukushima plant until 2015. “The problem would only be exacerbated for foreign workers.”
Kazumi Takagi, a sociology professor at Gifu University, has conducted interviews with nuclear plant workers.
Noting the need for special protective gear to work at the Fukushima site, Takagi said: “Unless workers can instantly understand the language when minor mistakes or sudden problems occur, it could lead to a major accident. That, in turn, could cause major delays in the work.”

April 23, 2019 Posted by | fukushima 2019 | , , | 1 Comment

Removal of fuel in pool at Fukushima’s melted reactor begins

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A Tokyo Electric Power Co. worker explains the operation at Unit 3 of Fukushima nuclear plant, in Okuma, Fukushima Prefecture, northeastern Japan Monday. April 15, 2019. The operator of the tsunami-wrecked nuclear plant has begun removing fuel from a cooling pool at one of three reactors that melted down in the 2011 disaster, a milestone in the decades-long process to decommission the plant.

 

April 15, 2019
The operator of the tsunami-wrecked Fukushima nuclear plant began removing fuel Monday from a cooling pool at one of three reactors that melted down in the 2011 disaster, a milestone in what will be a decades-long process to decommission the facility.
Tokyo Electric Power Co. said workers started removing the first of 566 used and unused fuel units stored in the pool at Unit 3. The fuel units in the pool located high up in reactor buildings are intact despite the disaster, but the pools are not enclosed, so removing the units to safer ground is crucial to avoid disaster in case of another major earthquake similar to the one that caused the 2011 tsunami.
TEPCO says the removal at Unit 3 will take two years, followed by the two other reactors, where about 1,000 fuel units remain in the storage pools.
Removing fuel units from the cooling pools comes ahead of the real challenge of removing melted fuel from inside the reactors, but details of how that might be done are still largely unknown. Removing the fuel in the cooling pools was delayed more than four years by mishaps, high radiation and radioactive debris from an explosion that occurred at the time of the reactor meltdowns, underscoring the difficulties that remain.
Workers are remotely operating a crane built underneath a jelly roll-shaped roof cover to raise the fuel from a storage rack in the pool and place it into a protective cask. The whole process occurs underwater to prevent radiation leaks. Each cask will be filled with seven fuel units, then lifted from the pool and lowered to a truck that will transport the cask to a safer cooling pool elsewhere at the plant.
The work is carried out remotely from a control room about 500 meters (yards) away because of still-high radiation levels inside the reactor building that houses the pool.
“I believe everything is going well so far,” plant chief Tomohiko Isogai told Japanese public broadcaster NHK. “We will watch the progress at the site as we put safety first. Our goal is not to rush the process but to carefully proceed with the decommissioning work.”
About an hour after the work began Monday, the first fuel unit was safely stored inside the cask, TEPCO spokesman Takahiro Kimoto said. Monday’s operation was to end after a fourth unit is placed inside the cask, he said. No major damage was found on the fuel unit Monday, but plant officials will closely examine if there are any pinholes or other irregularities, Kimoto said.
The removal, however, raises a storage capacity concern at the plant because the common pool, where fuel from the Unit 3 pool heads to, already has 6,000 fuel units and is almost full. Kimoto said TEPCO has made room at the common pool for the incoming fuel by moving years-old and sufficiently cooled fuel into dry casks for safer, long-term storage, though further details are being worked out.
In 2014, TEPCO safely removed all 1,535 fuel units from the storage pool at a fourth reactor that was idle and had no fuel inside its core when the March 11, 2011, earthquake and tsunami occurred.
Robotic probes have photographed and detected traces of damaged nuclear fuel in the three reactors that had meltdowns, but the exact location and other details of the melted fuel are largely unknown. Removing fuel from the cooling pools will help free up space for the subsequent removal of the melted fuel, though details on how to gain access to it have yet to be decided.
Experts say the melted fuel in the three reactors amounts to more than 800 tons, an enormous amount that is more than six times that of the 1979 accident at Three Mile Island, where one reactor had a partial core melt.
In February, a remote-controlled robot with tongs removed pebbles of nuclear debris from the Unit 2 reactor but was unable to remove larger chunks, indicating a robot would need to be developed that can break the chunks into smaller pieces. Toshiba Corp.’s energy systems unit, which developed the robot, said the findings were key to determining the proper equipment and technologies needed to remove the melted fuel, the most challenging part of the decommissioning.
TEPCO and government officials plan to determine methods for removing the melted fuel from each of the three damaged reactors later this year so they can begin the process in 2021.

April 23, 2019 Posted by | fukushima 2019 | , , , | Leave a comment

Abe visits Fukushima Daiichi plant

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During a visit Sunday, Prime Minister Shinzo Abe listens as technicians explain the current situation at the Fukushima No. 1 nuclear power plant in Okuma, Fukushima Prefecture.
April 14, 2019
Prime Minister Shinzo Abe says the government will continue the task of decommissioning the Fukushima Daiichi nuclear power plant. The nuclear accident at the plant in 2011 was triggered by an earthquake and tsunami that hit northeastern Japan.
 
Abe visited Fukushima Prefecture on Sunday to inspect the decommissioning work and the ongoing reconstruction of the prefecture.
 
He attended a ribbon-cutting ceremony for the opening of a new municipal office in the town of Okuma.
An evacuation order was lifted for two districts of Okuma on Wednesday. This was the first lifting of restrictions in a town hosting the plant.
 
Abe then visited the plant for the first time in five years and seven months.
He encouraged workers taking part in the decommissioning project, and handed them a letter of thanks.
 
Abe later told reporters that his cabinet ministers are united in reconstructing Fukushima Prefecture as well as northeastern Japan after the 2011 disaster. He said they have reconfirmed his administration’s basic policy that they are all reconstruction ministers.
 
He said that although the decommissioning work has been making steady progress, there are still many problems to cope with. These include the disposal of contaminated water accumulating in the plant compound. Abe said the project is facing a crucial moment. He said he plans to visit the prefecture again at the start of the torch relay for the 2020 Tokyo Olympics.

 

April 23, 2019 Posted by | fukushima 2019 | , , | Leave a comment

TEPCO to start removing fuel at Fukushima’s No. 3 reactor

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Workers lower the last part of a semi-cylindrical covering on top of the No. 3 reactor building.
April 12, 2019
The operator of the crippled Fukushima No. 1 nuclear power plant will start removing nuclear fuel from the No. 3 reactor as early as next week through equipment controlled remotely due to high radiation levels inside the building.
This will mark Tokyo Electric Power Co.’s first attempt to remove spent fuel from one of the three reactors that experienced a meltdown during the 2011 nuclear accident.
All spent fuel has already been removed from the No. 4 reactor.
TEPCO workers will use remote control to remove nuclear fuel assemblies kept in the pool on the upper floors of the No. 3 reactor building.
Utility officials acknowledge that the process will not be easy, as they have no experience conducting such a dangerous task remotely.
The 566 nuclear fuel assemblies in the storage pool will be removed under a plan expected to take two years to complete.
TEPCO wants to remove the assemblies as quickly as possible owing to concerns that another major earthquake or tsunami could further damage the reactor building and equipment. The No. 3 reactor will also serve as a test case for eventually removing spent nuclear fuel from the No. 1 and No. 2 reactor buildings.
Under the plan, workers will be stationed in a control room about 500 meters from the reactor building and use remote control equipment while observing the process through monitors.
Each nuclear fuel assembly will be lifted and transferred to a special transport container that can hold up to seven such assemblies in water. The container will then be carried out of the reactor building by crane, which will then lower the container outside of the building to a trailer about 30 meters below at ground level.
As a hydrogen explosion blew off the roof of the No. 3 reactor building in the wake of the 2011 nuclear accident, a semi-cylindrical copper covering has been placed over the building to prevent radioactive materials from spreading when the spent nuclear fuel is being removed.
All 1,535 nuclear fuel assemblies at the No. 4 reactor building were removed by the end of 2014. Radiation levels were comparatively low so workers could enter the building to work on the removal.
A TEPCO official in charge of the process called the removal at the No. 4 reactor “normal operating procedures,” but admitted that remote control operations added a new dimension of difficulty.
The utility has experienced problems with the crane and other equipment to be used at the No. 3 reactor.
Under TEPCO’s plan compiled shortly after the nuclear accident, all spent nuclear fuel was to have been removed from all four reactors by the end of fiscal 2021.
“We do not believe the process will proceed with zero problems,” said Akira Ono, president of the Fukushima Daiichi Decontamination and Decommissioning Engineering Co.
The work at the No. 3 reactor will serve as a model for a similar process planned for the No. 1 and No. 2 reactor buildings to start in fiscal 2023.
Government and TEPCO officials have said they will consider a detailed plan for removing spent nuclear fuel from those two buildings after reviewing the work done at the No. 3 reactor building.
The two other reactor buildings present different hurdles for workers.
The top floor of the No. 1 reactor building is covered with debris from a collapsed ceiling and damaged crane, the removal of which has proved difficult. Workers have also confirmed that the lid on top of the containment vessel has shifted, meaning radiation levels inside the building are likely even higher than in the No. 3 reactor building.
It thus remains to be seen if the same equipment to be used for the No. 3 reactor can be used for the No. 1 building. To prevent leaking of radioactive materials, the lid for the containment vessel will first have to be moved back into place.
While the No. 2 reactor building did not suffer major structural damage, large amounts of radioactive materials are believed to be trapped inside the building, meaning radiation levels are also very high there.
The level at the top floor is so high that any worker remaining there for one hour would quickly exceed the annual radiation exposure level. After decontamination, the upper part of the No. 2 reactor building will have to be taken apart to remove the spent fuel. However, this poses the major problem of preventing the spewing of radioactive materials during that process.
“To be honest, it will be difficult to say that no problems will emerge that will force a change in plans,” said Toyoshi Fuketa, chairman of the Nuclear Regulation Authority.

April 14, 2019 Posted by | fukushima 2019 | , , | 1 Comment

Local firm to take on hazardous demolition at Fukushima plant

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A crane and equipment used for training to demolish an exhaust stack in Hirono, Fukushima Prefecture
April 11, 2019
OKUMA, Fukushima Prefecture–Work will soon start at the crippled Fukushima No. 1 nuclear power plant to demolish a 120-meter-tall exhaust stack that has kept workers at bay due to high radiation levels.
Given the hazardous nature of the project, Able Co., the local company that will undertake the task, will use remote controlled equipment deployed on a 750-ton crane to “slice” through the upper half of the structure.
The work will begin in May at the earliest and is expected to take up to six months. It is regarded as a crucial phase in the decommissioning process of the plant’s reactors.
The exhaust stack was badly damaged in a hydrogen explosion caused by the nuclear accident following the 2011 Great East Japan Earthquake and tsunami.
A 2015 survey showed radiation levels of 2 sieverts per hour around the stack, sufficient to kill anybody who spends more than a few hours in the area.
Able, originally headquartered just 2 kilometers from the nuclear plant, put together a special squad for training last autumn.
There are four exhaust stacks at the plant designed to ventilate reactor buildings.
The stack to be demolished is situated between the No. 1 and No. 2 reactor buildings. Its upper part was damaged when the No. 1 reactor building blew up on March 12, 2011.
The inside and outside of the stack were heavily contaminated because Tokyo Electric Power Co., operator of the plant, used it to release highly radioactive gases to lower pressure inside the reactor during the nuclear crisis.
Some parts of the exhaust stack are badly compromised. The Nuclear Regulation Authority noted that the structure would pose a danger if it fell.
TEPCO asked Able, which has been involved in regular reactor checkups and piping work at the nuclear plant, to demolish it. Able developed special equipment to cut the upper part of the exhaust stack with a rotary cutter.
At one point, the company considered using a hydraulic or laser cutter, but decided not to for fear of increasing the volume of radioactive water or triggering a fire.
“We are a construction company, so we concentrated on combining technologies to deal with the issue, not producing equipment from scratch,” said Tetsuo Sato, 45, leader of the on-site project team.
The demolition equipment will be manipulated remotely from a control room in a converted bus.
One fear is that strong gusts of winds could affect the operation. Workers will operate the equipment by watching images captured by 160 cameras mounted on and around the device.
Able has switched its headquarters to Hirono, also in Fukushima Prefecture, as a temporary measure. About 70 percent of its 200-strong work force hails from the prefecture.
The exterior of the bus is festooned with messages by children of employees, such as, “Be careful” and “Operate safely.”
“We, as a local company, want to bring back peace of mind to residents by completing this task successfully,” said Isamu Okai, 51, who oversees the demolition project.

April 14, 2019 Posted by | fukushima 2019 | , , | Leave a comment

Unclear debris map casts shadow over decommissioning of Fukushima plant

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Pebble-like sediment believed to be nuclear fuel debris is lifted by a special device inside the No. 2 reactor containment vessel at the Fukushima Daiichi Nuclear Power Station.
April 9, 2019
TOKYO — The government and Tokyo Electric Power Co. (TEPCO) are set to launch full-scale probes of the inside of the No. 1 through No. 3 reactors at the disaster-stricken Fukushima Daiichi Nuclear Power Station this fiscal year, in an attempt to determine which reactor to work on first to remove fuel debris — a critical step for decommissioning the facility.
However, the interior of the No. 2 reactor, which is most likely to be the first to go through the debris removal process, has turned out to be different from what had originally been expected, underscoring the difficulties entailing the removal work. Since many companies are involved in the process, how to pass down the know-how acquired over the course of the more than 30 year-decommissioning process also poses a challenge.
“At present, it is difficult to clearly say we are going to remove all fuel debris,” said Akira Ono, who leads the decommissioning project, at a regular press conference by TEPCO on March 28, while noting that the utility will not back down from its ultimate goal of full debris removal.
If TEPCO fails to take out all debris from the nuclear plant, the very premise for dismantling the facility and returning the plot to its original state will be undermined. Such a scenario would adversely affect the disaster recovery plans envisaged by the national government and the Fukushima Prefectural Government. While awareness about the difficulty of debris removal has been shared among concerned parties, the actual dismal situation had not been recognized until TEPCO conducted the first debris survey at the No. 2 reactor on Feb. 13.
In that survey, a remotely controlled special device that was injected into the No. 2 reactor’s containment vessel succeeded in lifting portions of sediment accumulated at the bottom, which were believed to be fuel debris. Officials involved were relieved because they “had been worried the material would not move at all,” according to Ono.
The radiation level of the material, measured at a distance of some 30 centimeters, was 7.6 sieverts per hour, far less than anticipated. If the sediment contained a good portion of nuclear fuel, the radiation doses ought to have been several hundred sieverts per hour, even eight years after the 2011 nuclear meltdowns.
This finding suggested that the sediment that TEPCO came in contact with in the survey was not the main nuclear fuel debris it was looking for. Many speculate that the surface of the sediment may mainly consist of metals including cladding tubes that used to cover nuclear fuels.
The question now is whether fuel debris exists beneath the surface of the sediment or if nuclear fuel still remains within the reactor pressure vessel, or even somewhere else. There are currently no prospects for TEPCO to ascertain an accurate distributions of debris.
The material that was lifted in the survey mostly comprised pebble-like sediment, weighing less than 1 kilogram in total. Meanwhile, fuel debris generated in the core meltdowns is estimated to total 237 metric tons at the No. 2 reactor alone and a combined 880 tons at the No. 1 through No. 3 reactors.
At the No. 2 reactor, TEPCO will conduct a more detailed survey on debris possibly in the latter half of this fiscal year and attempt to collect small amounts of samples. At the No. 1 reactor, several apparatus including a robot submarine will be used to launch a full-scale survey inside the reactor to try to collect debris this fiscal year. As for the No. 3 reactor, the power company is apparently planning to prioritize removal of spent fuel, as related devices have gone through a series of glitches.
Unlike the other reactors, the No. 2 reactor did not suffer a hydrogen explosion in the 2011 disaster. Therefore, the No. 2 reactor remains the primary candidate for the first full-scale debris removal work, which is hoped to start in 2021.
With regard to the No. 1 and No. 3 reactors, the utility has yet to be able to reach materials appearing to be debris. The decommissioning of the nuclear plant is scheduled to be completed in 2051, a full 40 years after the triple meltdowns, but a concrete path toward that goal is not yet in sight.
“We have no choice but to remove whichever debris we can,” said a senior official with the Ministry of Economy, Trade and Industry.
Naoyuki Takaki, professor of nuclear engineering at Tokyo City University, commented, “There could ultimately be a decision to stop debris removal after pulling out as much debris as possible. In that case, we would have no option but to consider building a sarcophagus like the one at the Chernobyl nuclear plant.”

April 14, 2019 Posted by | fukushima 2019 | , , , | Leave a comment

Fukushima Unit 2; New Containment Panorama Photos

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April 1, 2019

A pair of new panoramic photos from inside Fukushima unit 2’s containment have been published. TEPCO provided the photos as part of ongoing updates on the disaster decommissioning work. The photos were stitched together from earlier containment inspection work then processed to bring out details of the photos. Also included in this report is details about the radiation and temperature readings inside containment, we explain that later in this report.

To read more on Fukuleaks:

http://www.simplyinfo.org/?p=17075&fbclid=IwAR1_Q_39LzdqLkkBzP9qwYPhAUrvsnpwvdtngLB9iCkKr4o5UVKxP262Yz4

April 8, 2019 Posted by | fukushima 2019 | , | Leave a comment