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Muons suggest location of fuel in unit 3

Some of the fuel in the damaged unit 3 of the Fukushima Daiichi plant has melted and dropped into the primary containment vessel, initial results from using a muon detection system indicate. Part of the fuel, however, is believed to remain in the reactor pressure vessel.

FD3 muon measurements Oct 2 2017)Structures within the reactor building of unit 3 can be seen in images obtained using muon data (Image: Tepco)

 

Muons are high-energy subatomic particles that are created when cosmic rays enter Earth’s upper atmosphere. These particles naturally and harmlessly strike the Earth’s surface at a rate of some 10,000 muons per square meter per minute. Muon tracking devices detect and track these particles as they pass through objects. Subtle changes in the trajectory of the muons as they penetrate materials and change in direction correlate with material density. Nuclear materials such as uranium and plutonium are very dense and are therefore relatively easy to identify. The muon detection system uses the so-called permeation method to measure the muon data.

Tokyo Electric Power Company (Tepco) installed a muon detection system on the first floor of unit 3’s turbine building. Measurements were taken between May and September this year.

Tepco said analysis of muon examinations of the fuel debris shows that most of the fuel has melted and dropped from its original position within the core.

Prior to the 2011 accident, some 160 tonnes of fuel rods and about 15 tonnes of control rods were located within the reactor core of unit 3. The upper and lower parts of the reactor vessel contains about 35 tonnes and 80 tonnes of structures, respectively.

The muon examination indicates that most of the debris – some 160 tonnes – had fallen to the bottom of the reactor pressure vessel and resolidified, with only about 30 tonnes remaining in the reactor core. Tepco said another 90 tonnes of debris remains in the upper part of the vessel.

The bulk of the fuel and structures in the core area dropped to the bottom of the reactor pressure vessel (RPV), Tepco believes. While part of the molten fuel is understood to have then fallen into the primary containment vessel (PCV), “there is a possibility that some fuel debris remains in the bottom of the RPV, though this is uncertain”, the company noted.

Similar muon measurements have already been conducted at units 1 and 2 at Fukushima Daiichi. Measurements taken at unit 1 between February and September 2015 indicated most of the fuel was no longer in the reactor’s core area. Measurements taken between March and July 2016 at unit 2 showed high-density materials, considered to be fuel debris, in the lower area of the RPV. Tepco said that more fuel debris may have fallen into the PCV in unit 3 than in unit 2.

FD1-3 fuel debris - September 2017 - 460 (Tepco)The current understanding of fuel location in units 1-3 (Image: Tepco)

 

Tepco said the results obtained from the muon measurements together with knowledge obtained from internal investigations of the primary containment vessels using remote-controlled robots will help it plan the future removal of fuel debris from the damaged units.

http://www.world-nuclear-news.org/RS-Muons-suggest-location-of-fuel-in-unit-3-0210174.html

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October 5, 2017 Posted by | Fukushima 2017 | , , | 1 Comment

Radioactive Water “Possibly” Leaked From Reactors For Months “By Error” Says Tepco

wrong gauges measuring 28 sept 2017.jpgA Tokyo Electric Power Company (Tepco) employee (center) speaks to the media in front of a monitor in the refrigerator building at the company’s Fukushima No.1 nuclear power plant, in Okuma, Fukushima, Japan, on February 23. The company’s attempt to clean up and recover the wrecked site has been beset by frequent delays and rising costs.

 

Fukushima Nuclear Disaster: Radioactive Water May Have Been Leaking From Reactors for Months

The Japanese company in charge of cleaning up one of the world’s worst nuclear disasters said Friday its latest error may have caused contaminated water to leak into the ground for nearly half a year.

The Tokyo Electric Power Company (Tepco) said it erroneously configured gauges used to measure groundwater levels in six wells near Fukushima No.1 nuclear power plant reactors Nos. 1 through 4, all of which were destroyed when a March 2011 earthquake and tsunami devastated the Japanese coast and caused a series of meltdowns at the plant.

The false readings, which have been relied on since April 19 and were discovered this week, meant that groundwater levels were actually more than two feet below what Tepco was measuring, The Japan Times reported. The company said this mistake caused groundwater levels to fall below the limit set to prevent radioactive water from flowing out of the plant and into the nearby wells, known as subdrains, at least once, in May.

Tepco spokesperson Shinichi Nakakuk said, however, the company’s readings did not show any significant increases in radioactivity outside of the facilities and that a leak was unlikely, according to Sky News.

Between May 17 and May 21, groundwater reportedly fell as much as 7 and a half inches below the safety levels at least eight times. Tepco has not been able to determine how long the dangerous levels persisted because they only measure the site hourly. Company officials said they were still investigating the incident, according to Japan’s NHK news outlet.

More than 15,000 people were killed when an earthquake and subsequent tsunami struck Japan’s east coast, where the Fukushima No. 1 nuclear power plant is located. The threat of radioactive contamination following meltdowns at Fukushima No. 1 nuclear power plant’s Nos.1, 2 and 3 reactors, as well as massive damage to the fourth, forced 150,000 residents to evacuate, most of whom have yet to return.

Since the disaster, plant owner Tepco has struggled through the recovery process, the price tag of which was raised to $192 billion last year, according to Reuters. The leading obstacle that the company faces is extracting the nuclear fuel that remains in the plant’s damaged nuclear reactors. The severe radiation levels have “killed” even robots specifically designed to swim underwater and detect the location of the melted nuclear fuel.

Lava-like rocks believed to be the elusive nuclear fuel were finally discovered in July using a small, custom-built robot known as “Little Sunfish,” according to Sky News. Actually removing the deadly substance, however, has once again been delayed and would not likely begin until 2023, according to Japanese officials.

Japan’s latest plan to clean up the site did not make any mention of what Tepco would do with about 777,000 tons of water contaminated with tritium, a nuclear byproduct that’s notoriously difficult to remove once mixed with water. In July, Tepco chairman Takashi Kawamura said the “decision has already been made” to dump the tritium-tainted water into the Pacific Ocean; however, he later said he would need Tokyo’s support to go through with the measure.

While Tepco and experts have said dumping the tritium-laced water used to cool down the reactors into the ocean would be relatively harmless, local fishermen and environmental activists have condemned the potential solution, saying it would further hurt the already damaged reputation of the region.

http://www.newsweek.com/fukushima-nuclear-plant-radioactive-water-leaking-months-674434

Botched Gauges Mean Radioactive Water Might Be Leaking From Fukushima

Radioactive, contaminated water may have leaked from the destroyed Fukushima Daiichi nuclear reactor in Japan into nearby groundwater, report plant officials. The incident has not been confirmed, but is suspected to have occurred because of a fault in well placement.

The wells around the reactors are designed to pump groundwater away from the facility. Tokyo Electric Power Company (TEPCO), which operates the plant, said that six wells in the vicinity of the reactors were actually a full three feet below the required safe height to avoid contamination. This means it’s possible that radioactive waste water has been leaking into the soil at those sites.

The mistake was noticed in April 2017 during tests that preceded the digging of a new well, and TEPCO launched a full investigation. The mistake was a result of TEPCO erroneously configuring the gauges in the wells, repeatedly giving them false readings of the groundwater levels at those sites.

TEPCO tested all six questionable sites and found that the groundwater has no elevated levels of radioactivity. A leak is therefore unlikely, according to TEPCO spokesman Shinichi Nakakuki.=

The Fukushima plant suffered a triple meltdown following the devastating 9.0 earthquake and tsunami that struck Japan in March 2011, killing around 16,000 people. After the meltdown that forced 174,000 people to abandon their homes, further contamination occurred when melted-down nuclear fuel seeped into the groundwater.

The wells are to prevent radioactive water from leaking into the Pacific, but TEPCO has had repeated troubles with managing thousands of tons of contaminated water. Shortly after the meltdown, an underground barrier of frozen soil was built, but in 2016 they revealed that the measure had been ineffective. In July 2013, TEPCO revealed that radioactive water was leaking from the plant into the Pacific Ocean, something they had previously denied. 

TEPCO has been severely criticized by the Japanese government and public for their mishandling of the meltdown and ensuing crisis. In 2016, three of TEPCO’s top executives, including former Chairman Tsunehisa Katsumata, were indicted on charges of criminal negligence.

They are also the subject of 30 class action lawsuits from displaced and injured residents. The most recent lawsuit was resolved earlier in September, when the company was ordered to pay 376 million yen ($3.36 million) to 42 plaintiffs.

https://sputniknews.com/environment/201709301057827423-radioactive-water-fukushima-well-leak/

Botched gauge settings might have contaminated Fukushima groundwater from April onward: Tepco

The discovery of falsely configured monitoring equipment at the stricken Fukushima No. 1 nuclear power plant means the groundwater flowing underneath it might have gotten contaminated from April onward, Tokyo Electric said Friday.

The utility said incorrect gauge settings were used to measure groundwater levels in six of the wells near reactors 1 and 4. This resulted in groundwater readings about 70 cm higher than reality, which means the beleaguered power utility has been mismanaging the groundwater there for months.

To prevent tainted water from leaking from the plant, Tokyo Electric Power Company Holdings Inc. installed water gauges so it could keep the groundwater levels in the wells a meter higher than the contaminated water in the buildings.

Tepco adjusts the amount of water in wells called subdrains around the buildings to keep the groundwater higher than the tainted water inside them, which prevents it from flowing out. If the groundwater levels sink below the level of the radioactive water, it might leak out.

On Friday, Tepco said the estimated groundwater level in one of the six subdrain wells close to reactor 1 fell below the level in the reactor building at least eight times during the five-day period to May 21 because the gauges were set incorrectly.

Groundwater levels were 2 mm to 19 mm lower than the level in the buildings, Tepco said, adding that it does not know precisely how long each of these problematic situations lasted because water level data is collected by the hour.

Tepco said groundwater levels in five other wells affected by the incorrect settings did not fall below the levels in the nearby reactor buildings.

All six are in the area surrounded by an underground ice wall designed to prevent groundwater leakage.

According to Tepco, the incorrect settings date as far back as April 19. The earliest error affected the gauge in a well where groundwater fell to hazardous levels.

In the world’s worst nuclear disaster since Chernobyl, reactors 1, 2 and 3 at the plant experienced core meltdowns and reactors 1, 3 and 4 were severely damaged by hydrogen explosions following a massive offshore earthquake that spawned large tsunami in March 2011.

https://www.japantimes.co.jp/news/2017/09/29/national/radioactive-water-may-leaking-fukushima-reactor-buildings-since-april-tepco/#.Wc8cghdx3re

October 3, 2017 Posted by | Fukushima 2017 | , , | Leave a comment

Multiple challenges remain to Fukushima nuclear cleanup

Japan_Nuclear_Challenges_21065.jpg

This Sept. 4, 2017 aerial photo shows Fukushima Dai-ichi nuclear power plant reactors, from bottom at right, Unit 1, Unit 2 and Unit 3, in Okuma, Fukushima Prefecture, northeastern Japan. The three reactors that had meltdowns together have 1,573 units of mostly used nuclear fuel rods that are still inside and must be kept cool in pools of water. They are considered among the highest risks in the event of another major earthquake, because the pools are uncovered. The plant operator, Tokyo Electric Power Co. or TEPCO, plans to begin removing the rods from reactor unit 3 in the fiscal year beginning next April 1. However, the latest roadmap delays removal of the rods from units 1 and 2 for three years until fiscal 2023, because further decontamination work and additional safety measures are needed.

Japan’s government approved on Tuesday, Sept. 26, 2017 a revision to the decommissioning plan for the Fukushima nuclear plant, delaying by two more years the removal of radioactive fuel rods in two of the three reactors damaged in the 2011 disaster. It still plans for melted fuel to be removed starting in 2021, but the lack of details about the duration raises doubts if the cleanup can be completed within 40 years. Kyodo News via AP, File)


TOKYO – Japan’s government approved a revised road map Tuesday to clean up the radioactive mess left at the Fukushima nuclear power plant after it was damaged beyond repair by an earthquake and tsunami in 2011. Decommissioning the damaged reactors is an uncertain process that is expected to take 30 to 40 years.

A look at some of the challenges:

THE FUEL RODS

The three reactors that had meltdowns together have 1,573 units of mostly used nuclear fuel rods that are still inside and must be kept cool in pools of water. They are considered among the highest risks in the event of another major earthquake that could trigger fuel rods to melt and release massive radiation due to loss of water from sloshing or structural damage because the pools are uncovered. The plant operator, Tokyo Electric Power Co., or TEPCO, plans to begin moving the rods from reactor Unit 3 in the fiscal year beginning April 1.


However, the latest road map delays removal of the rods from units 1 and 2 for three years until fiscal 2023, because further decontamination work and additional safety measures are needed. Ironically, because the building housing reactor 3 was more heavily damaged, it is easier to remove that unit’s fuel rods. The fuel rods will be moved to a storage pool outside the reactors, and eventually sent for long-term storage in what are known as dry casks.

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THE MELTED FUEL

By far the hardest part of decommissioning Fukushima will be removing the fuel that melted and presumably spilled out of the reactor cores. In July, an underwater robot for the first time captured images inside the primary containment chamber of Unit 3. They showed a large number of solidified lava-like rocks and lumps on the chamber’s floor, believed to be melted fuel mixed with melted and mangled equipment and parts of the structure.

The search for melted fuel in units 1 and 2 has so far been unsuccessful. The water level is lower, so crawling robots have been tried, but they have been obstructed by debris as well as extremely high radiation levels. Despite the unknowns about the melted fuel and debris and their whereabouts, the road map calls for finalizing the removal method in 2019, and starting actual removal at one of the reactors in 2021. The government-funded International Research Institute for Nuclear Decommissioning is developing robots and other technology to carry out the work.

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CONTAMINATED WATER

TEPCO has treated and stored a massive amount of radioactive water — about 800,000 tons — and the volume is growing every day. Cooling water leaks out of the damaged reactors and mixes with groundwater that seeps into the basements of the reactor building, increasing the amount of contaminated water. The utility has managed to halve the volume to 200 tons per day by pumping up groundwater via dozens of wells dug upstream from the reactors, as well as installing a costly “ice wall” by freezing the ground to block some of the water from coming in and going out.

The water is stored in hundreds of tanks that cover much of the plant property. They get in the way of decommissioning work and pose another risk if they were to spill out their contents in another major earthquake or tsunami. After treatment, the water still contains radioactive tritium, which cannot be removed but is not considered harmful in small amounts. Experts say controlled release of the water into the ocean is the only realistic option, but TEPCO has not moved forward with that plan because of opposition from fishermen and residents who fear a negative image and possible health impact.

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RADIOACTIVE WASTE

Japan has yet to develop a plan to dispose of the highly radioactive waste that will come out of the Fukushima reactors. Under the road map, the government and TEPCO will compile a basic plan during fiscal 2018. Managing the waste will require new technologies to compact it and reduce its toxicity. Finding a storage site for the waste seems virtually impossible, as the government has not been able to find a site even for the normal radioactive waste from its nuclear power plants. The prospect raises doubts about whether the cleanup can really be completed within 40 years.

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http://www.miamiherald.com/news/business/article175387901.html

September 26, 2017 Posted by | Fukushima 2017 | , , , | Leave a comment

Spent Nuclear Fuel Removal at Fukushima Plant Delayed Again

Japan muddles on with Fukushima’s melted and “spent” fuel. The three year delay for emptying the reactors “spent” irradiated nuclear fuel into a dry cask storage runs the risk of another major earthquake causing a loss of cooling in the pools without containments and another major release of radiation. Plans for removing the melted reactor cores from Units 1, 2 and 3 still defied by inability to locate it.

 

sept 26 2017 fuel removal delayed.png

Fukushima Nuclear Plant Scrapping Plan Faces Another Delay

A key decision in decommissioning the crippled Fukushima Daiichi nuclear plant is being delayed. The Japanese government and operator made the announcement on Tuesday while giving an update on the roadmap for scrapping the plant.

In their first such update in 2 years, officials said they will postpone their decision on the method for removing molten fuel debris by one year, until fiscal 2019.

Experts believe that when the plant went into triple meltdown in 2011, most of the fuel inside the reactors collected at the bottom of containment vessels. They still don’t know the exact location, but possible molten fuel debris was caught on camera in July. The removal of this debris is considered the most challenging part of the plant’s decommissioning.

Originally, officials considered filling the containment vessels with water to block radiation while removing the debris. But now, they say they’re leaning towards a method called dry removal.

Experts say that method comes with safety challenges. “Because the containment vessel will not be filled with water, there is a possibility that radioactive substances may leak and get dispersed,” says Hosei University Visiting Professor Hiroshi Miyano.

Officials also gave an update on plans for the removal of spent nuclear fuel rods in 2 of the plants reactors. The rods are in storage pools and won’t be removed until fiscal 2023. That’s 3 years later than planned. The official timeline for scrapping the plant remains the same — about 30 to 40 years in total.

https://www3.nhk.or.jp/nhkworld/nhknewsline/nuclearwatch/fukushimanuclearplantscrapping/

Spent nuclear fuel removal at Fukushima plant pushed back again

n-roadmap-a-20170927-870x438Cabinet ministers attend a meeting at the Prime Minister’s Office on Tuesday to discuss a delay in the road map for decommissioning the Fukushima No. 1 nuclear power plant.

 

The government and Tokyo Electric Power Company Holdings Inc. decided Tuesday to further delay the removal of spent nuclear fuel left near two of the three reactors that suffered meltdowns at the Fukushima No. 1 nuclear plant.

In the road map for decommissioning the plant, revised for the fourth time since it was first crafted in 2011, highly radioactive spent fuel will be extracted from the cooling pools of reactors 1 and 2 starting in fiscal 2023 instead of fiscal 2020.

The decision marks the third delay for the removal plan, with the last adjustment coming in June 2015. The government said new technical issues and the need to take safety precautions led to the latest change.

The cleanup process is set to be completed in around 30 to 40 years.

Spent fuel removal at the plant’s reactor 3 will go ahead in fiscal 2018 as planned, having already been pushed back earlier this year.

In the decommissioning process, the removal of fuel rod assemblies from the spent fuel pools in reactor buildings is one of the key steps before extracting melted fuel debris. Reactors 1, 2 and 3 suffered core meltdowns following the March 2011 earthquake and tsunami disaster.

The removal of melted fuel debris has also been delayed, with an extraction plan set to be decided in fiscal 2019, pushed back from the first half of fiscal 2018.

Despite the delay in finalizing specific methods, the road map maintains a 2021 start for debris extraction, the most challenging part of the decommissioning process.

A method currently considered feasible by the government involves removing debris from the sides of the reactors after partially filling them with water.

The road map newly sets the goal of cutting the amount of underground water at the plant to address contaminated water buildup. Underground water — which gets mixed with accumulated radioactive water generated in the process of cooling the damaged reactors — is to be cut to around 150 tons per day in 2020 from the current 200 tons.

The road map does not mention a specific schedule for the disposal of processed water that still contains radioactive tritium.

The plan was first crafted in December 2011 in the wake of the meltdowns, the world’s worst nuclear crisis since the 1986 Chernobyl disaster.

Attempts have been made to confirm the situation inside the damaged reactors using specialized robots. A survey in July this year captured for the first time images of what is likely to be melted nuclear fuel at the bottom of reactor 3.

Isamu Kaneda, deputy mayor of the Fukushima Prefecture town of Futaba, expressed regret over the delay.

The town’s rebuilding depends on the development of decommissioning. It’s unfortunate,” Kaneda said. “But at the same time, the decommissioning process is an unprecedented project. It needs to be conducted carefully, so we can’t just ask them to speed it up.”

https://www.japantimes.co.jp/news/2017/09/26/national/spent-nuclear-fuel-removal-fukushima-plant-pushed-back/#.WcqxGxdx3rc

Spent nuclear fuel removal at Fukushima plant to be delayed again

Screenshot from 2017-09-27 00-36-28.png

 

TOKYO (Kyodo) — The government and Tokyo Electric Power Company Holdings Inc. decided Tuesday to delay again the start of removing spent nuclear fuel left near two of the three reactors which suffered a meltdown at the Fukushima complex.

In the road map for decommissioning the Fukushima Daiichi plant, revised for the fourth time since it was first crafted in December 2011, highly radioactive spent nuclear fuel will be extracted from the Nos. 1 and 2 units’ cooling pools starting in fiscal 2023 instead of fiscal 2020.

It is the third time that the schedule for spent fuel removal has been pushed back at the Nos. 1 and 2 reactors, with the previous postponement taking place in June 2015. The government said new technical issues and the need to take safety precautions led to the latest schedule change.

The cleanup process is to be completed in around 30 to 40 years.

For the No. 3 reactor at the Fukushima plant, the schedule to remove spent nuclear fuel during fiscal 2018 is unchanged after having already been pushed back earlier this year.

In the decommissioning process, taking out fuel rod assemblies from the spent fuel pools inside reactor buildings is one of the key steps before extracting melted fuel debris from the Nos. 1 to 3 reactors, all of which suffered core meltdowns following the March 2011 earthquake and tsunami disaster.

The schedule for extraction of the melted fuel debris at the reactors was also revised, with the determination of a specific approach to remove the debris to be made in fiscal 2019, rather than in the originally planned first half of fiscal 2018.

Despite the delay in finalizing specific methods, the road map kept the start of the debris extraction, the most challenging part of the decommissioning process, at 2021.

A method currently considered feasible by the government is debris removal from the side of the three crippled reactors by partially filling them with water.

The road map newly sets the goal of cutting the amount of underground water at the plant to address contaminated water buildup at the site. Underground water, which gets mixed with accumulated radioactive water generated in the process of cooling the damaged reactors — is to be cut to around 150 tons per day in 2020 from the current 200 tons.

It did not mention a specific schedule for disposal of processed water that still contains radioactive tritium.

The road map was first crafted in December 2011 in the wake of the 2011 disaster which triggered at the Fukushima plant the world’s worst nuclear crisis since the 1986 Chernobyl disaster.

Attempts have been made to confirm internal conditions of the damaged reactors using robots. A survey robot captured images of what is likely to be melted nuclear fuel at the bottom of the No. 3 reactor for the first time in July this year.

http://mainichi.jp/english/articles/20170926/p2g/00m/0dm/064000c

 

September 26, 2017 Posted by | Fukushima 2017 | , , | Leave a comment

TEPCO to delay emptying fuel storage pools at Fukushima plant

reactor 1 left reactor 2 right 21 sept 2017.pngThe No. 1 reactor building, left, and the No. 2 reactor building at the crippled Fukushima No. 1 nuclear plant

 

Plans to remove fuel rods from two spent fuel pools at the Fukushima No. 1 nuclear plant will be delayed by up to three years because of difficulties in clearing debris and reducing radiation levels.

The government and plant operator Tokyo Electric Power Co. originally expected to start emptying the storage pools at the No. 1 and No. 2 reactor buildings in fiscal 2020.

But they plan to move the starting time to fiscal 2023 in their first review in two years of the roadmap for decommissioning the stricken nuclear plant, sources said Sept. 20.

They are expected to announce the revised roadmap later this month.

A survey of the upper levels of the two reactor buildings, where the storage pools are located, found debris piled up in a much more complicated way than initially envisaged.

That will lengthen the time needed to clear the debris, thus delaying the removal of the fuel rods, the sources said.

In addition, radiation levels remain extremely high inside the buildings.

The No. 1 reactor’s storage pool holds 392 nuclear fuel assemblies, while the No. 2 reactor’s pool has 615 assemblies.

Work to remove the 566 assemblies from the No. 3 reactor’s pool is scheduled to begin in the middle of fiscal 2018 as originally planned.

The three reactors melted down in the 2011 disaster, triggered by the magnitude-9.0 Great East Japan Earthquake and tsunami.

The review of the decommissioning roadmap is also expected to revise the target of “starting the removal” of melted nuclear fuel and debris in the three reactors in 2021 to “aiming to start the removal” in 2021.

But the government and TEPCO will maintain the goal of completing the decommissioning in “30 to 40 years,” the sources said.

http://www.asahi.com/ajw/articles/AJ201709210034.html

September 22, 2017 Posted by | Fukushima 2017 | , , | Leave a comment

Nuclear Fuel Retrieval Delayed

Screenshot from 2017-09-20 22-26-54.png

 

A step in the decommissioning of Japan’s crippled Fukushima Daiichi nuclear plant could be delayed by 3 years.

Japan’s government and the plant operator say they need more time before they remove spent nuclear fuel rods in 2 of the reactors. The rods are in storage pools and now won’t be removed until fiscal 2023. They say they first need to remove rubble and radioactive substances.

The plan to remove molten fuel debris has not changed. This step is considered the biggest hurdle to decommissioning the plant.

The plant went into triple meltdown following the 2011 earthquake and tsunami. It’s expected to take 40 years to scrap the plant.

https://www3.nhk.or.jp/nhkworld/nhknewsline/nuclearwatch/nuclearfuelretrievaldelayed/

September 20, 2017 Posted by | Fukushima 2017 | , | Leave a comment

Nuclear Lessons Learned: US & Japan NONE!

From Majia’s blog

Japan’s Nuclear Regulatory Authority has bowed to pressure and is allowing TEPCO, a company with a culture that has been berated by this same agency, to re-start reactors:

EDITORIAL: NRA too hasty in giving green light to TEPCO to restart reactors (2017, September 14). The Asahi Shimbun, http://www.asahi.com/ajw/articles/AJ201709140030.html

Although the Nuclear Regulation Authority has decided to give the green light to Tokyo Electric Power Co. to restart nuclear reactors, we question the fitness of the utility, which is responsible for the accident at the Fukushima No. 1 nuclear power plant, to manage nuclear facilities. The NRA has been screening TEPCO’s application to resume operations of the No. 6 and No. 7 boiling-water reactors at its Kashiwazaki-Kariwa nuclear plant in Niigata Prefecture. The NRA on Sept. 13 acknowledged with conditions that TEPCO is eligible for operating nuclear plants after examining the company’s safety culture and other issues. 

Meanwhile, Japan’s nuclear commission is calling not only for a return to nuclear (with at least 20% of its fuel mix targeted for nuclear), but has also endorsed MOX fuel in a move that defies reason, especially given the conditions of Fukushima reactor 3 (which was running MOX at the time of the accident):

Mari MARI YAMAGUCHI (2017, September 14 ) Japan commission supports nuclear power despite Fukushima. The Seattle Times, http://www.seattletimes.com/business/japan-commission-supports-nuclear-power-despite-fukushima/

TOKYO (AP) — Japan’s nuclear-policy-setting Atomic Energy Commission issued a report Thursday calling for nuclear energy to remain a key component of the country’s energy mix despite broad public support for a less nuclear-reliant society. The report approved by the commission calls for nuclear energy to make up at least 20 percent of Japan’s supply in 2030, citing the government energy plan. It says rising utility costs from expensive fossil fuel imports and slow reactor restarts have affected Japan’s economy. The resumption of the nuclear policy report is a sign Japan’s accelerating effort to restart more reactors. “The government should make clear the long-term benefit of nuclear power generation …

The report also endorsed Japan’s ambitious pursuit of a nuclear fuel cycle program using plutonium, despite a decision last year to scrap the Monju reactor, a centerpiece of the plutonium fuel program, following decades of poor safety records and technical problems. Japan faces growing international scrutiny over its plutonium stockpile because the element can be used to make atomic weapons. 

And to top it all off, Japan is now setting up its first “restoration hub” in Futaba:

Noriyoshi Otsuki (2017, September 15). First ‘hub’ set up in Fukushima no-entry zone to speed rebuilding. The Asahi Shimbun, http://www.asahi.com/ajw/articles/AJ201709150058.html

An area in the no-entry zone of Futaba, a town that co-hosts the crippled Fukushima No. 1 nuclear power plant, became the first government-designated “rebuilding hub” after the 3/11 disaster. The designation on Sept. 15 means decontamination will speed up and infrastructure restored so the evacuation order in the town center can be lifted by spring 2022. Most of Futaba is currently located in a difficult-to-return zone because of high radiation levels. Rebuilding efforts have not started there yet, even six-and-a-half years since the nuclear accident unfolded.

As noted in the article, Futaba is located in the difficult to return zone. Here is a screenshot from TEPCO’s 2016 report on air monitoring in the Futaba evacuation zone:

index.png

 

index2.png

 

The air dose in Futaba is very high, with the highest reading reported at 9.6 microsieverts an hour.

Locating the first restoration hub in Futaba, located in close proximity to the still-unstable plant, seems like a propaganda move, rather than a thoughtful risk decision.

Fukushima is still belching radioactivity (especially from unit 3), as illustrated in this screenshot from yesterday:

index3.png

 

The plant is still at risk from earthquakes and lifequefaction.

I must conclude from this series of news reports that neither Japan nor the US are capable of learning when it comes to nuclear policy making.

http://majiasblog.blogspot.fr/2017/09/nuclear-lessons-learned-us-japan-none.html

September 20, 2017 Posted by | Fukushima 2017 | , | 1 Comment

Low 134Cs/137Cs ratio anomaly in the north-northwest direction from the Fukushima Dai-ichi Nuclear Power Station

img_4ef1531e2c9e492609857ed7ab016146101330.jpg

 

Highlights

We present new data of 134Cs/137Cs around Fukushima Daiichi Nuclear Power Station.
The entire area of the low 134Cs/137Cs ratio anomaly around the FDNPS is revealed.
The low 134Cs/137Cs ratio anomaly is coincident with a plume trace.
The anomaly occurs in the area which had been contaminated before March 13, 2011.

Abstract

A low 134Cs/137Cs ratio anomaly in the north-northwest (NNW) direction from the Fukushima Dai-ichi Nuclear Power Station (FDNPS) is identified by a new analysis of the 134Cs/137Cs ratio dataset which we had obtained in 2011–2015 by a series of car-borne surveys that employed a germanium gamma-ray spectrometer.

We found that the 134Cs/137Cs ratio is slightly lower (0.95, decay-corrected to March 11, 2011) in an area with a length of about 15 km and a width of about 3 km in the NNW direction from the FDNPS than in other directions from the station.

Furthermore, the area of this lower 134Cs/137Cs ratio anomaly corresponds to a narrow contamination band that runs NNW from the FDNPS and it is nearly parallel with the major and heaviest contamination band in the west-northwest.

The plume trace with a low 134Cs/137Cs ratio previously found by other researchers within the 3-km radius of the FDNPS is in a part of the area with the lower 134Cs/137Cs ratio anomaly that we found.

Our result suggests that this lower 134Cs/137Cs ratio anomaly is the area which was contaminated before March 13, 2011 (UTC) in association with the hydrogen explosion of Unit 1 on March 12, 2011 at 06:36 (UTC) and it was less influenced by later subsequent plumes.

http://www.sciencedirect.com/science/article/pii/S0265931X17301947

 

September 20, 2017 Posted by | Fukushima 2017 | , , , , | Leave a comment

Drone to Measure Radiation inside Fukushima Daiichi Reactor and Turbine Buildings

n-drone-a-20170910-870x558.jpgThis drone will be used to measure radiation inside the reactor and turbine buildings at the meltdown-hit Fukushima No. 1 power plant.

 

Drone to measure radiation in tainted Fukushima No. 1 buildings

Tokyo Electric plans to measure radiation in heavily contaminated buildings at the Fukushima No. 1 power plant as it prepares to decommission its damaged reactors, officials at the utility said.

The data from the drone is expected to help Tokyo Electric Power Company Holdings Inc. create 3-D maps and identify areas of high radiation that workers should avoid.

The drone, 93 cm wide and 83 cm long, has four propellers and can fly for around 15 minutes. Tepco, as the struggling utility is known, expects to use it in the reactor buildings and the turbine buildings.

In February, Tepco tested a drone in the turbine building for the No. 3 reactor, one of three that experienced meltdowns after the March 2011 earthquake and tsunami.

After improving its performance, it decided to use the drone to gauge radiation but it is still deciding where to start, the officials said.

The government and Tepco want to start debris extraction work in 2021 and are in the process of determining a specific approach for removing the molten fuel from each reactor and updating the decommissioning road map.

https://www.japantimes.co.jp/news/2017/09/09/national/drone-measure-radiation-tainted-fukushima-no-1-buildings/#.WbS8LxdLfrd

Drone to measure radiation inside tainted Fukushima plant buildings

TOKYO (Kyodo) — The operator of the crippled Fukushima Daiichi nuclear power plant is planning to use a drone to measure radiation inside heavily contaminated structures as it prepares to decommission damaged reactors there, according to officials of the operator.

Data obtained from its use is expected to help the operator, Tokyo Electric Power Company Holdings Inc., create 3-D maps and identify areas with high-level radiation inside buildings where workers cannot stay safely.

The drone envisioned for the task is 93 centimeters wide and 83 cm long, and, equipped with four propellers, can fly for around 15 minutes. The operator envisions its use inside buildings that house damaged reactors and inside those housing turbines.

In February Tepco, as it is known, tested a drone inside the turbine building for the No. 3 reactor, one of three reactors that experienced meltdowns in the March 2011 earthquake and tsunami.

After improving its performance, the plant operator has decided to put the drone into use for radiation measurement. But it is still considering where it should begin using the machine, according to the officials.

The government and Tepco are aiming to start debris extraction work from 2021, and are currently in the process of determining a specific approach to removing melted fuel from each damaged reactor and of updating their decommissioning road map.

http://mainichi.jp/english/articles/20170910/p2g/00m/0dm/008000c

 

 

 

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

Construction of the Cover for Fukushima Daiichi Reactor 3 Continues

reactor 3 dome aug 9 2017.jpg

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

Radiation Detected in Fukushima Daiichi Worker’s Nasal Cavities

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The Fukushima No. 1 nuclear power plant is shown on Feb. 22, 2016. A worker at the plant was found to have been exposed to a small amount of radiation during a routine safety check on Friday.

 

TEPCO: Worker exposed to small radiation dose at Fukushima

A worker dismantling tanks at Japan’s wrecked Fukushima No. 1 nuclear power plant was found to have been exposed to a small amount of radiation during a routine safety check on Friday, plant operator Tokyo Electric Power Co. (TEPCO) said.

Radiation was detected in nasal cavities of the worker, an unidentified man in his 30s, a TEPCO spokesman said on Friday. The company estimated the amount of radiation at up to 0.010 millisieverts–less than a typical chest X-ray of 0.05 millisieverts–and said it did not pose an immediate health risk.

Reported radiation exposure incidents have been rare during work to clean up the plant, devastated by the March 11, 2011, magnitude 9 earthquake and tsunami that left nearly 16,000 people confirmed dead, with more than 2,000 officially unaccounted for.

The TEPCO spokesman said the last Fukushima No. 1 radiation exposure incident in official records was for a worker exposed to at least 2 millisieverts in January 2012.

http://www.asahi.com/ajw/articles/AJ201709080046.html

 

Fukushima worker exposed to small amount of radiation, Tepco says

A worker dismantling tanks at the wrecked Fukushima No. 1 nuclear plant was found to have been exposed to a small amount of radiation during a routine safety check on Friday, plant operator Tokyo Electric said.

Radiation was detected in the nasal cavities of the worker, an unidentified man in his 30s, a spokesman for Tokyo Electric Power Company Holdings Inc. said on Friday.

The company estimated the amount of radiation at up to 0.010 millisieverts — less than a typical 0.05-millisievert chest X-ray — and said it did not pose an immediate health risk.

Reported radiation exposure incidents have been rare during work to clean up the plant, which was devastated by a magnitude-9 earthquake and tsunami on March 11, 2011, that left nearly 16,000 people confirmed dead and more than 2,000 officially unaccounted for.

The Tepco spokesman said the last Fukushima No. 1 radiation exposure incident in official records was for a worker who was exposed to at least 2 millisieverts in January 2012.

https://www.japantimes.co.jp/news/2017/09/08/national/fukushima-worker-exposed-small-amount-radiation-tepco-says/#.WbRVGBdLfrc

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

Battling nuclear demons: Mental health issues haunt those who were the first line of defense after 3/11

1.jpgWorkers from Tokyo Electric Power Co. travel by bus toward the power plant in April 2011.

 

Ryuta Idogawa traces the onset of his battle with mental illness to a moment not long after his parents had been relocated to Saitama from their hometown of Futaba, Fukushima Prefecture, in the spring of 2011.

Idogawa recalls with almost claustrophobic clarity how, as he boarded a train to travel to Tokyo, a sense of panic set in when the carriage walls seemed to close in and fellow passengers in the rush-hour squash started to stare — piercing, even accusatory stares, he thought.

I was sweating, but I felt really cold and my heart was racing, faster and faster,” says Idogawa, 33. “I could hardly breathe. I thought, ‘Oh My God! I’m going to die.’”

Today, Idogawa continues to suffer from such panic attacks, although their frequency has decreased. To mitigate the problem, he has found a job near to his apartment and avoids trains whenever possible. On occasions when rail travel is unavoidable, he steers clear of express trains, as there are fewer opportunities to “escape” should panic set in, he explains. Medication, too, has sometimes helped.

One likely cause of this continuing condition, he believes, is guilt — guilt that in the aftermath of the March 11, 2011, disasters that struck northeastern Japan and claimed 18,455 lives (including 2,561 still listed as missing), he was powerless to prevent the accident that occurred at his place of work, the Fukushima No. 1 nuclear power plant.

At the beginning I wasn’t even aware of my condition, or I felt somehow separate from it and from what was happening,” says Idogawa, a former employee at plant operator Tokyo Electric Power Co. “Looking back, maybe I was hiding it or hiding from it.”

Such mental afflictions are not unusual among Tepco’s Fukushima plant workers, especially in the aftermath of the disasters, experts say. According to a study of some 1,500 workers compiled by Jun Shigemura and others, all had experienced a variety of stressors (see table on page 12) relating to their direct experiences of the disasters, losses of loved ones and the backlash from a disgruntled public, in particular the 160,000 Fukushima residents who were evacuated due to the contamination of their homes and land that resulted from the multiple reactor meltdowns at Fukushima No. 1.

Jun Shigemura, an associate professor at the National Defense Medical College’s department of psychiatry, sits at his office in Tokorozawa, Saitama Prefecture, on Aug. 15.

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According to lead researcher Shigemura, 29.5 percent of workers at the plant subsequently displayed symptoms of high post-traumatic stress responses (PTSR), including flashbacks and avoidance of reminders of the terrifying events they went through.

Around 1 in 5 Tepco workers at neighboring Fukushima No. 2 plant also showed similarly high levels of PSTR, even though there was no serious damage to the four reactors there.

Continued surveys of the workers by Shigemura, an associate professor at the National Defense Medical University’s Department of Psychiatry, and other experts say that while the overall influence of disaster-related experiences on PTSR of workers had decreased since 2011, it remains high.

For some workers, this is going to continue for a long time, probably years and decades,” says Shigemura, who specializes in the mental health of disaster workers.

This is consistent with previous findings following the Chernobyl nuclear accident in 1986, he says. While scientists then had assumed that cancers and other malignant disorders would be the biggest health risk, mental health issues turned out to be far more prevalent, he says.

Indeed, studies have shown that mental health problems, including post-traumatic stress disorder (PTSD), depression and suicide ideation, were still high and remained the most prevalent problem for the Chernobyl cleanup workers even 20 years after the disaster, Shigemura says. “So I think we can say with some confidence that the Fukushima workers also carry a very high risk of developing long-term mental health issues.”

Furthermore, while PTSD is often thought of as the main persisting illness in such disasters, Shigemura says factors such as depression, anxiety and alcohol abuse are also likely to linger for some time.

More than 6½ years on from the Fukushima disasters, former Tepco employee Idogawa knows all about these problems, although how he got there was a gradual, but nonetheless alarming, process.

A graduate of Toden Gakuen, Tepco’s now-defunct training academy, Idogawa had lived and breathed the utility’s doctrine since he was just 15 years old. It centered as much around technical excellence as it did corporate group identity and loyalty, and those who followed it were rewarded with the kind of mouthwatering salaries that placed them very much among the elite of their communities.

3.jpgRyuta Idogawa believes that guilt over the nuclear accident that occurred at the Fukushima No. 1 power plant on March 11, 2011, has been a contributor to his continuing struggles with mental illness.

 

On the day of the disasters, Idogawa was on leave, having worked a night shift the previous day. Even before the Earth’s violent convulsions had subsided, however, he was heading toward the plant from his nearby home, arriving there just before the black waves of the 15-meter mega-tsunami engulfed the facility.

As one of the plant’s operators, his day-to-day duties took place inside the central control room for reactors 1 and 2, where he was charged with scrutinizing the instruments that monitored the plant’s oldest reactor, the outmoded unit 1. By the time he joined the on-duty team of 14 operators, the tsunami had extinguished all available power sources, plunging the control room into complete darkness and disarray.

With monitoring apparatus also dependent on power, there was no way of knowing for certain if coolants were still reaching the reactor cores. Believing that this was unlikely, by midnight Idogawa calculated that the first reactor, and probably the second, were already in meltdown.

This was supported by readings on portable monitoring devices that showed radiation levels inside the control room were climbing. Idogawa joined all the other operators on the reactor 2 side of the windowless room, only venturing over toward the opposite first reactor side, where radiation levels were considerably higher, to make occasional, but futile, checks of the lifeless instruments.

Over the next two days, he remained inside the control room, still in the dark about the safety of his family and friends as meltdowns and explosions began to take their toll.

On March 14, he was ordered aboard a company bus bound for the Fukushima No. 2 nuclear power plant, which had fared far better than its older neighbor and had been designated an off-duty recuperation and medical center for workers at Fukushima No. 1. It was during that 10-kilometer journey that his focus slowly shifted to the outside world, which had a distinctly fishbowl appearance through his full-face mask.

At one point, just past the entrance to Fukushima No. 1 plant, I looked out of the window and saw a man walking his dog like it was just another ordinary day,” Idogawa says. The scene seemed all the more bizarre because while most workers aboard the bus were wearing masks, the man went about his morning stroll completely unprotected. “I wondered, ‘What is he doing out there’ and wanted to shout out to him to get inside away from the high radiation.”

At the Fukushima No. 2 plant there was a noticeably subdued air. There was little food, no cigarettes and no heat to stay warm amid the snowy, wintery cold.

Idogawa had originally tried to make the trip to the Fukushima No. 2 plant via his own car, which was parked near the newly built quake-proof center at Fukushima No. 1 and was highly contaminated, but he couldn’t get it started.

I wanted to take the car to give me an escape should things get worse. That’s what I was expecting,” he says. “I actually think that’s what (plant chief Masao) Yoshida was thinking, too — that everyone, himself included, should get out of there and go to the Fukushima No. 2 plant.”

Over the following months, the cumulation of these events began to take their toll. Idogawa became part of a team that the foreign media nicknamed the “Fukushima 50,” groups of workers on rotating shifts that split their time between battling the reactor meltdowns and recuperating at the Fukushima No. 2 plant, or at residences to which they had been evacuated.

With his home now off limits inside the 20-kilometer no-go zone, Idogawa had evacuated to an apartment in Koriyama, where time proved to be anything but a healer. With nothing to do but await his next shift, his mind wandered, among other things, to the man walking his dog and the tens of thousands of residents like him who had been forced to flee their homes as invisible radioactive substances fell on their land.

He began to suffer stomach cramps, chronic insomnia and depression, and turned to the only thing he could think of that would help him sleep and wash away the unwelcome images in his head: whisky — and lots of it.

I felt bad for those people, like it was my fault,” he says. “I couldn’t do anything (to prevent the accident) and as a member of Tepco, I thought I was to blame.”

Takeshi Tanigawa, a professor of public health at Jutendo University’s graduate school of medicine, has been involved in mental health surveys of Fukushima plant workers.

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Such self-criticism and guilt have been major contributors to enduring mental illnesses among plant workers, according to Takeshi Tanigawa, a professor of public health at Jutendo University’s graduate school of medicine, who has also been involved in the mental health surveys of Fukushima plant workers.

We found that those who have experienced such criticism and discrimination have a high degree of psychological distress or PTSR, more than two times higher than control subjects,” he says, adding that with 80 percent of workers being local hires, the bashing, sometimes at the hands of friends and relatives, was even more difficult to take.

Of all the stressors — including the life-threatening experiences, the loss of loved ones and possessions, and so on — this was the “most influential” among those workers with persisting mental health issues, says Tanigawa, who also has worked as a part-time occupational physician at the nuclear plants in Fukushima Prefecture since 1991.

One thing we can be grateful for is that nobody has committed suicide at the plant,” Tanigawa says. “However, alcohol abuse, increased smoking and obesity are prevalent, and can lead to life-threatening diseases and early mortality.”

However, both Tanigawa and Shigemura believe that the enduring impact of the various “complex stressors” is the main reason why other contract workers and early respondents to the disasters will not display similar long-term mental health problems. This includes personnel from Tepco’s various subcontracting companies and members of Tokyo Fire Department’s Hyper Rescue brigade, who entered the plant on March 17, 2011, in an attempt to pump water onto the overheating reactor 3.

Yukio Takayama, former deputy superintendent and chief of the 8th district Hyper Rescue battalion, revisits his former workplace in Tachikawa on July 13.

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One of the leaders of that Tokyo Fire Department team, Yukio Takayama, who was at the time deputy superintendent of the 8th district Hyper Rescue battalion based in the city of Tachikawa, says a number of firefighters had been deeply affected by the thought of entering such a highly irradiated part of the plant, which offered an invisible fear factor quite different from that to which they were accustomed.

Indeed, Takayama fell sick during the operations and while they left an indelible impression, the 48-hour encounter with the radiation-spewing plant was unlikely to leave any long-term mental scars, he says. “It was stressful, but there were others who were up there for much, much longer,” he says.

A former subcontractor employee, who was working at the Fukushima No. 1 plant at the time of the 2011 disasters, says he had not heard of any mental health issues among subcontractor workers. However, as they made up almost 90 percent of the total plant workforce, he couldn’t discount the possibility.

One thing that was different for us was that we were never forced, or obliged, to return to the plant,” the worker says in an interview, speaking on condition of anonymity. “Like many others, I evacuated from the plant and never went back, but if I had, I suppose it’s perfectly possible I may have succumbed to mental illness.”

One other group that reportedly has been afflicted by mental health problems comes from an unusual quarter, and one that has not been a factor in previous nuclear accidents. American sailors who were taking part in the U.S. military’s “Operation Tomodachi” relief mission at the time of the Tohoku disasters were inadvertently exposed to a plume of radiation that passed over their ships, which were anchored off the Pacific coast north of Fukushima.

Several hundred have since developed life-changing illnesses, including leukemia and other cancers — a result, they claim, of the radioactive plume. Many have also suffered persisting mental health issues, either due to concerns of physical illnesses that have resulted from the exposure or extreme stress brought about by concerns for potential future illnesses, including cancers.

6.jpgSailors aboard the aircraft carrier USS Ronald Reagan scrub the flight deck to decontaminate it while the ship is operating off the coast of Japan providing humanitarian assistance on March 23, 2011.

 

Unlike the nuclear plant workers, these sailors had no protective clothing. In fact, some of them literally had no shirts on their backs because they had given all their clothing away to people they saved from the tsunami waves,” says Charles Bonner, a lawyer representing some 400 sailors who have filed a lawsuit against Tepco and U.S. nuclear reactor manufacturer General Electric. “And because they had given away all their bottled water to tsunami survivors, they were drinking desalinated water that had also been contaminated. I do not doubt the psychological impact of the disasters on the plant workers, but at least they had masks and other protective clothing, as required by law. The sailors, however, knew nothing of their exposure and were literally marinated in the radiation.”

Idogawa’s exposure levels were also in excess of acceptable levels by the time he quit Tepco in January 2012 to protest the utility’s poor treatment of workers — who were, in most cases, also victims — and the government’s announcement the previous month that the plant had been brought “under control,” which was completely at odds with what he saw.

Whether you take the viewpoint of a Tepco employee or a local resident, the outcome was far from satisfactory,” Idogawa says. “As a plant operator we caused a huge accident — the worst kind. Technicians train over and over, and are charged with ensuring this kind of thing doesn’t happen. That the accident did happen makes us the lowest of the low. From the viewpoint of a resident, the disaster meant they couldn’t go home. That we destroyed entire communities was bad enough. However, they were our communities as well.”

Despite his disgruntlement, Idogawa is hopeful that his former employer will implement measures to monitor and treat mental health issues that he believes continue to persist among many workers.

When asked to comment on post-accident care of its workers for this article, Tepco says it was unable to provide details due to privacy issues. It did, however, continue to hand out “health check” questionnaires, the nationalized utility says. The utility also would not comment on its policy regarding on-site care, which came into question following rumors that an on-site psychiatrist fled the Fukushima No. 1 plant following the 2011 disasters.

7.jpgAn employee from Tepco apologizes to a Tomioka resident during a meeting in the city of Koriyama, Fukushima Prefecture, on Feb. 11, 2013.

 

Shigemura, whose surveys and subsequent treatment of plant workers was brought to an abrupt halt by Tepco in 2015, believes continued “surveillance” of workers is imperative. One reason is due to the possibility of “delayed onset” mental illnesses, which sometimes occur among “survivors” following a variety of situations, from disasters and conflicts to car accidents and familial loss. Some Vietnam War veterans, for example, only developed mental illnesses following the start of the Gulf War 20 years later, he explains.

During his research, Shigemura came across one plant worker, who was also an evacuee, who had experienced such a phenomenon. Three years later, after the evacuation order had been lifted, he re-visited his hometown, which was overgrown and deserted.

When he evacuated, he hadn’t fully accepted the burden of the disaster,” Shigemura says. “It was only when he returned home that he felt the gravity of the disaster and was forced to confront it. And that’s when he experienced late-onset PTSD.”

Shigemura also believes there is a need for a major reconsideration of disaster management measures, especially those that can mitigate the psychological havoc a nuclear accident can wreak.

We need multiple layers of support in preparation for these disasters because when they happen people tend to act in ways they might not usually act, especially following a disaster you cannot easily perceive, such as a nuclear accident,” he said. “They might run away and you can’t blame them for that, because they also have roles as fathers, mothers and so on. There needs to be measures to respond effectively to such eventualities and to provide effective care for those most affected.”

Fukushima plant worker stressors

Work-related experience

  • Earthquakes and tsunami
  • Plant explosions
  • Radiation exposure
  • Extreme overwork
  • Worker shortage

Survivor experience

  • Mandatory evacuation
  • Property loss
  • Family dispersion

Grief — loss of:

  • Colleagues
  • Family members
  • Friends

Social backlash

  • Public criticism
  • Discrimination
  • Harassment
  • Guilt as “perpetrators” of a nuclear accident

https://www.japantimes.co.jp/news/2017/09/02/national/science-health/battling-nuclear-demons-mental-health-issues-haunt-first-line-defense-311/#.WasAzxdLfrc

September 3, 2017 Posted by | Fukushima 2017 | , | Leave a comment

Debris to be removed from side of Fukushima reactors

_w850.jpgWorkers wearing protective suits and masks work on the No. 2 reactor building at the Fukushima Daiichi nuclear power plant.

 

TOKYO – A state-backed entity tasked with supporting the decommissioning of the Fukushima nuclear power station proposed Thursday that melted fuel be removed from the side of three of the crippled reactors as part of the process to scrap the complex.

Based on a formal proposal, the government and the plant operator Tokyo Electric Power Company Holdings Inc (TEPCO) will determine specific approaches to carry out the process on each reactor next month and update the plant decommissioning road map.

Under its strategic plan for 2017, the Nuclear Damage Compensation and Decommissioning Facilitation Corp called for the removal of the fuel by partially filling the three reactors with water to cover some of the nuclear debris while allowing access to carry out the work.

The entity also pointed out that the decommissioning work requires phased efforts while maintaining flexibility, as the project still faces many uncertainties.

The extraction work from the Nos. 1-3 reactors at the Fukushima Daiichi nuclear complex, which suffered meltdowns following the massive 2011 earthquake and tsunami disaster, is seen as the most difficult step toward the ultimate goal of decommissioning the entire complex, set to take at least 30 to 40 years to complete.

The government and TEPCO are currently aiming to start the extraction work from 2021.

Under the plan, the Nuclear Damage Compensation and Decommissioning Facilitation body proposed using a remotely controlled apparatus to shave debris from the underside of the lower section of the reactors’ containment vessel while controlling the level of water.

Debris remains not only in the reactors’ pressure vessel but also piled and scattered at the bottom of the containment vessel that houses the reactor vessel.

As for debris left in the reactors’ pressure vessel, the entity will consider removing it from the upper part of the reactors, it said.

The decommissioning body had previously considered a strategy to fill the containment vessel with water as water is effective in containing radiation, but it has shelved the idea as the reactor containers are believed to have been damaged and would leak.

Following a magnitude-9.0 earthquake in March 2011, tsunami inundated the six-reactor plant, located on ground 10 meters above sea level, and flooded power supply facilities.

Reactor cooling systems were crippled and the three reactors suffered fuel meltdowns, while hydrogen explosions damaged the buildings housing the Nos. 1, 3 and 4 reactors.

The Nuclear Damage Compensation and Decommissioning Facilitation entity was established after the Fukushima crisis, the worst nuclear disaster since Chernobyl, to help the utility pay damages. The state-backed entity holds a majority stake in the operator.

https://japantoday.com/category/national/Debris-to-be-removed-from-side-of-Fukushima-reactors

September 2, 2017 Posted by | Fukushima 2017 | , | Leave a comment

Muscle robots’ being developed to remove debris from Fukushima reactors

Hitachi-GE testing variety of simply structured, radiation-resistant equipment

20170818_Fukushima-reactor_article_main_image.jpgThe Unit 1 reactor building at the Fukushima Dai-ichi nuclear power plant of the Tokyo Electric Power Co. (TEPCO) in Okuma town, Fukushima prefecture, June 21, 2017.

 

TOKYO — A joint venture between Japanese and American high-technology power houses Hitachi and General Electric is developing special robots for removing nuclear debris from the Fukushima Daiichi nuclear power plant, the most difficult task in decommissioning the plant’s six reactors, three of which suffered core meltdowns in the March 2011 accident.

The machines under development by Hitachi-GE Nuclear Energy are called “muscle robots,” as their hydraulic springs operate like human muscles. The company, based in Hitachi, Ibaraki Prefecture, is stepping up efforts to complete the development project in time for the start of debris removal in 2021.

Hitachi-GE is testing the arms of the robots at a plant of Chugai Technos, a Hiroshima-based engineering service company, located a 30-minute drive from the center of the city. The testing is taking place in a structure with a life-size model of the primary containment vessel of the No. 1 reactor at the Fukushima plant. The robots awkwardly move about, picking up concrete lumps standing in for fuel debris.

“The robots are based on a concept completely different from those of conventional robots,” said Koichi Kurosawa, a senior Hitachi-GE engineer heading the development project. Hydraulics are being used because electronics cannot survive in the extreme environment inside the reactors.

“Asked if the robots are applicable to other nuclear power plants, I would say the possibility is low,” Kurosawa said, noting that the robots are designed to work amid intense radiation.

New challenges

While Hitachi-GE has built many nuclear reactors, it is encountering a variety of new challenges in developing the muscle robots simply because of the tough work required to retrieve fuel debris.

In the nuclear accident caused by the March 2011 earthquake and tsunami, cooling the fuel rods became impossible, and melted uranium fuel dropped from them. Some of the fuel broke through nuclear reactor pressure vessels and solidified as fuel debris containing uranium and plutonium.

The debris is estimated to weigh more than 800 tons in total. The insides of the PCVs at the Fukushima plant are directly exposed to the debris and are emitting radioactivity strong enough to kill a human within a few minutes.

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The International Research Institute for Nuclear Decommissioning, a Tokyo-based research institute for decommissioning nuclear plants, and three reactor makers — Hitachi-GE, Toshiba and Mitsubishi Heavy Industries — have been attempting to ascertain conditions inside the reactor buildings at the Fukushima plant by means of camera- and dosimeter-equipped equipment.

https://asia.nikkei.com/Tech-Science/Science/Muscle-robots-being-developed-to-remove-debris-from-Fukushima-reactors

September 2, 2017 Posted by | Fukushima 2017 | , , | Leave a comment

Fukushima ice wall facing doubts as project nears completion

Barrier will block only a fraction of groundwater contamination

0823N-Fukushima-Daiichi_article_main_image

Work has begun on the final 7 meters of an “ice wall” at the Fukushima Dai-ichi nuclear power plant.

 

TOKYO — Tokyo Electric Power Co. Holdings began Tuesday the final phase of an underground “ice wall” around the crippled Fukushima Daiichi nuclear power plant intended to reduce groundwater contamination, though experts warn the bold project could be much less effective than once hoped.

At 9 a.m., workers began activating a refrigeration system that will create the last 7 meters of a roughly 1.5km barrier of frozen earth around the plant’s reactor buildings, which were devastated by the earthquake, tsunami and nuclear meltdowns of March 2011. Masato Kino, an official from the Ministry of Economy, Trade and Industry supervising the cleanup, spoke cautiously at the occasion, noting that “producing results is more important than the simple act of freezing” that particular segment of soil.

Tepco estimates that roughly 580 tons of water now pass through the ice wall on the reactor buildings’ landward side each day, down from some 760 tons before freezing of soil commenced in March 2016. About 130 tons daily enter the reactor buildings themselves, and Tepco hopes completing the wall will bring that figure below 100 tons.

By this math, the near-complete wall blocks only a little over 20% of groundwater coming toward it. But, as Japan’s Nuclear Regulation Authority said Aug. 15 when approving the wall’s final stage, the barrier is “ultimately only a supporting measure” to other systems preventing contamination. The main line of defense is a so-called subdrain system of 41 wells around the reactor buildings that pump up 400 to 500 tons of water daily, preventing clean water from entering the site and contaminated water from leaving it.

Slow going

Freezing of earth around the facility has been conducted gradually, amid concerns that highly contaminated water inside could rush out should the water level inside the reactor buildings drop. “Working carefully while keeping control of the water level is a must,” said Yuzuru Ito, a professor of civil and environmental engineering at Setsunan University.

It is unclear precisely when the wall will be complete. The plan is to freeze soil 30 meters deep over the course of two or three months, completing the barrier as soon as this fall. But as the gap in the wall narrows, water flows through it more quickly, making soil there more difficult to freeze. “Water is flowing quickly now, and so it is difficult to proceed as we have so far,” a Tepco representative said.

Japan has spent some 34.5 billion yen ($315 million) in taxpayer funds on the wall, expecting the icy barrier to put a decisive end to groundwater contamination at the Fukushima plant. It now appears that a dramatic improvement is not likely, though the wall will still require more than 1 billion yen per year in upkeep. “The frozen-earth barrier is a temporary measure,” said Kunio Watanabe, a professor of resource science at Mie University. “Some other type of wall should be considered as well.”

https://asia.nikkei.com/Tech-Science/Tech/Fukushima-ice-wall-facing-doubts-as-project-nears-completion

 

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