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Part of the frozen soil barrier may have thawed at the Fukushima Daiichi Nuclear Power Plant. Steel pipes are being driven into the ground to stop groundwater flow.

Nov. 25, 2021
Tokyo Electric Power Company (TEPCO) announced on November 25 that it may have thawed part of the frozen soil barrier wall built around the No. 1 to No. 4 reactors at the Fukushima Daiichi Nuclear Power Plant (Okuma and Futaba towns, Fukushima Prefecture) to prevent the inflow of groundwater. The company has announced that it will try to stop the flow of water by driving several steel pipes into the wall. The project will start as early as early December, and if the temperature in the ground continues to rise, additional steel plates will be driven in.
 According to TEPCO, a thermometer installed in the ground at the intersection of the southwest side of Unit 4 and the underground tunnel for drainage confirmed that the temperature exceeded zero degrees Celsius in late August. Since late September, the temperature has sometimes been above 10 degrees Celsius. A spokesperson explained at a press conference that the groundwater level outside the wall was high, and water pressure may have created a water path.
 The steel pipe is 35 centimeters in diameter and up to six meters long. Nine of them will be driven into the ground outside the frozen soil wall, which may have thawed, to create a wall three to four meters wide.
 The freezing wall, which has been in operation since 2017, was built to prevent groundwater from flowing into the reactor building, where melted nuclear fuel (debris) remains from the accident, and to reduce the amount of contaminated water generated. The wall is about 1.5 kilometers long. About 1,600 freezing pipes (30 meters long) were driven into the ground. The freezing pipes are about 1,600 tubes (30 meters long) driven into the ground and circulated with a cooling liquid of 30 degrees Celsius to freeze the surrounding soil. (Kenta Onozawa)
https://www.tokyo-np.co.jp/article/144800

November 26, 2021 Posted by | Fukushima 2021 | , , | Leave a comment

Temperature of Fukushima Daiichi’s “frozen earth wall” rises again – TEPCO: “Function is being maintained.

Nov. 16
As a measure to reduce the amount of contaminated water from the Fukushima Daiichi Nuclear Power Plant, the temperature in the ground has been rising in a part of the “frozen soil wall” that freezes the ground around the buildings to prevent the inflow of underground water.
Tokyo Electric Power Company (TEPCO) has stated that the freezing wall is still functioning, but the cause of the problem is not known at this time.

The “frozen earth wall” is one of the measures to reduce the amount of contaminated water. Pipes are embedded around the buildings of the Fukushima Daiichi Nuclear Power Plant, and liquid at 30 degrees below zero is poured into the pipes and frozen, forming an “ice wall” that prevents underground water from flowing into the buildings.

TEPCO has installed thermometers in the “frozen earth wall” to measure the underground temperature, and it has been above 0 degrees Celsius in some areas on the mountain side of the Unit 4 reactor of the Fukushima Daiichi Nuclear Power Plant since mid-September, rising to 11.29 degrees Celsius on the 12th of last month.

After that, the temperature hovered around 5 degrees and dropped to 1.13 degrees on the 11th of this month, but it rose again to 8.88 degrees on the 14th, 9.65 degrees on the 15th, and 11.03 degrees on the 16th, exceeding 10 degrees for the first time in about a month.

The Tokyo Electric Power Company (TEPCO) investigated the inside of the frozen soil wall from the 10th to the 12th of this month, digging at a depth of about 2.8 meters where the temperature was rising, but could not find the cause.

The Tokyo Electric Power Company (TEPCO) has stated that “there has been no change in the level of groundwater and the function to control the inflow of water has been maintained.


https://www3.nhk.or.jp/lnews/fukushima/20211116/6050016369.html?fbclid=IwAR3Z6CT3b8ER4XjkTPda9E0gZ4SoyJimxDTR3WgZJ2sp69YzKlYgB3j0 Oig

November 18, 2021 Posted by | Fukushima 2021 | , | Leave a comment

Temperature rises over 10 degrees Celsius in some parts of the “frozen earth wall” to reduce contaminated water at Fukushima Daiichi Nuclear Power Plant

October 28, 2021

As a countermeasure to reduce the amount of contaminated water from the Fukushima Daiichi Nuclear Power Plant, it was found that the temperature of the ground in some parts of the “frozen soil wall”, which freezes the ground around the buildings to prevent the inflow of underground water, has been rising above 0 degrees Celsius since the middle of last month, reaching a maximum of 10 degrees Celsius. The Tokyo Electric Power Company (TEPCO) is investigating the cause of the problem, saying that it does not affect the function of the wall to prevent the inflow of underground water.

The “frozen earth wall” is one of the measures to reduce the amount of contaminated water. Pipes are embedded around the buildings of the Fukushima Daiichi Nuclear Power Plant, and liquid at 30 degrees below zero is poured into the pipes and frozen, forming an “ice wall” that prevents groundwater from flowing into the buildings.

The Tokyo Electric Power Company (TEPCO) has installed thermometers in the “frozen earth wall” to measure the underground temperature, and in some areas located on the mountain side of the No. 4 reactor at the Fukushima Daiichi Nuclear Power Plant, the temperature, which is usually below freezing, has been rising and has been above zero since the middle of last month.

The temperature in the area where the increase was confirmed was between 1 meter and 4 meters deep, and the temperature exceeded 10 degrees Celsius on some days.

The freezing wall is about 10 meters thick, and TEPCO has stated that there is no significant difference in the water level between the inside and outside of the wall, so there is no impact on its ability to control the inflow of groundwater.

It is possible that water leaked from cracks in the drainage channel that intersects the frozen soil wall and seeped into the frozen area, causing the temperature to rise.

https://www3.nhk.or.jp/news/html/20211028/k10013326291000.html?fbclid=IwAR3MBXXF1TlJxKAfYqkv0A5QS9Oddy0SJV86EvVul_HnWKcFSdaWmOH0Vp 8

October 29, 2021 Posted by | Fukushima 2021, Fukushima continuing | , | Leave a comment

Freezing wall to be used for longer period than expected, “trump card” of countermeasure against contaminated water at Fukushima Daiichi Nuclear Power Plant, without sufficient verification

 The frozen soil barrier wall at the Fukushima No. 1 Nuclear Power Plant of the Tokyo Electric Power Company (TEPCO) was built at a cost of 34.5 billion yen. Initially, TEPCO had planned to finish the work by 2021, but five years have passed since the freeze, and a large amount of contaminated water continues to be generated, with no prospect of even reaching zero. The ice wall, which will cost hundreds of millions of dollars to maintain every year, will enter long-term operation without sufficient verification. (Kenta Onozawa)


Freezing soil with cooling liquid, annual maintenance cost of billions of yen
The freezing wall was built to prevent groundwater from the mountains from entering the buildings where highly radioactive materials such as melted nuclear fuel (debris) remain after the accident. Freezing began in March 2004, and the entire area was frozen in nearly two years. The annual maintenance costs, including electricity for freezing, cost more than one billion yen when the system was first introduced, and TEPCO is bearing the cost.

From December 2007 to January 2009, there were a series of problems with cooling liquid leaking from a total of five frozen pipes. According to TEPCO, all of them are located under the road near the reactor building, and it is highly likely that the vibration of passing vehicles caused fatigue damage to the metal parts.


 TEPCO, which had not envisioned long-term operation of the plant, had been repairing problems only after they occurred, but from this year, it has set a frequency for replacement of parts and will prepare replacement parts in advance. A spokesperson said, “The frozen earth wall is effective and will be used continuously. However, from this year, the frequency of replacement will be set and replacement parts will be prepared in advance.


Groundwater through gaps, limited effect
 ”In March 2006, TEPCO announced that it would build a freeze-earth wall at the Fukushima Daiichi Nuclear Power Plant.
 In March 2006, TEPCO announced an estimate that the frozen soil wall prevented about 95 tons of groundwater per day from entering the buildings. Without the wall, the amount would have been 189 tons per day, and the company stressed that the amount had been halved.
 However, there is a lack of evidence for the estimate, as it was based on an evaluation of the period when there was little rainfall, and it does not distinguish between the effects of other measures, such as the pumping up of groundwater by sub-drainage wells around the building. Toyoshi Sarada, chairman of the Nuclear Regulation Authority (NRA), has declared that “the main role of groundwater countermeasures is to pump up the sub-drainage.
 At the press conference when the calculations were released, Naohiro Masuda, who was the chief decommissioning officer of TEPCO (now president of JNFL), stated clearly that “we will continue to verify” the effectiveness of the frost wall. However, the spokesman now avoids explaining, saying, “It is difficult to show the effects of individual measures.


Calls from the Regulatory Commission for an alternative plan
Initially, the government and TEPCO had set a goal of stopping the generation of contaminated water by around 2009. However, they still do not know where the groundwater is coming from.
 The amount of contaminated water, which was 490 tons per day in FY2003, was reduced to about 140 tons in FY2008, but zero was not achieved, and the goal was set back to 100 tons in 2013. TEPCO said, “We will continue with the current measures until 2013. After that, we are still studying.


 The cost of maintaining the frost wall will be covered by the electricity bills paid by consumers to TEPCO. In the regulatory commission’s study group, there is a strong opinion among experts that “from the viewpoint of cost-effectiveness, the frozen soil wall should be abandoned and steel plates or concrete walls should be embedded. In response to this opinion, TEPCO simply replied, “We are considering it,” and even 10 years after the accident, there is no end in sight to the contaminated water measures.

https://www.tokyo-np.co.jp/article/117551?fbclid=IwAR22EHyloXPo8UJUlsQrTBreHGz1ZNzT_z11KkUNStmn6p7x6LJ6Sp6uPgA

October 29, 2021 Posted by | Fukushima 2021 | , | Leave a comment

Fukushima Daiichi Frozen Wall Leaks

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Fukushima nuclear plant’s frozen wall leaks

Jan. 17, 2020

Tokyo Electric Power Company says coolant has seeped out from an underground frozen soil wall built around its crippled Fukushima Daiichi nuclear plant.

The frozen soil wall came into operation four years ago. It was built to keep groundwater from flowing into reactor buildings. They were damaged by the March 2011 earthquake, tsunami and subsequent nuclear meltdowns.

The utility firm, TEPCO, says it found coolant leaking at three locations from components that connect pipes in the wall. The company had noticed a reduction in coolant in its tank earlier this month and was searching for the cause.

TEPCO says it believes 20,000 of 1.1 million liters of the coolant has leaked, but that this will not affect the operation of the wall.

The company says it will replace the components in the wall and repair another leak that was found in December.

https://www3.nhk.or.jp/nhkworld/en/news/20200117_10/

hjlmmùùFukushima Daiichi Nuclear Power Station is seen in Okuma, Fukushima Prefecture, in this photo taken from a Mainichi Shimbun helicopter in August 2019.

Four coolant leaks found in Fukushima nuke plant ‘ice wall’ pipes

January 17, 2020

TOKYO — Coolant has been found leaking from pipes in the underground wall of frozen soil surrounding reactor buildings at the tsunami-ravaged Fukushima Daiichi Nuclear Power Station at four locations, its operator said.

According to Tokyo Electric Power Company Holdings, Inc. (TEPCO), the coolant liquid contains calcium chloride, commonly used as a snow-melting agent, and is not an environmental contaminant.

The utility has confirmed that a total of about 20 cubic meters of the coolant has leaked from the pipes. Though the coolant supply to the leaking pipes has been halted, TEPCO does not expect the ice wall to suffer any loss of function. The pipes concerned are between the plant’s No. 2 and No. 3 reactor buildings.

TEPCO noticed the problem in late 2019 when the volume in a coolant tank dropped abnormally. Workers examined the ice wall piping and found leaks in the joints. The company is poised to investigate the cause of the leak and replace the problematic parts.

The utility started the operation of the underground wall of frozen soil at the stricken complex in 2016. Coolant chilled to minutes 30 degrees Celsius is circulated through buried pipes, freezing the soil around the reactor buildings to prevent ground water from flowing into the structures

https://mainichi.jp/english/articles/20200117/p2a/00m/0na/022000c

January 21, 2020 Posted by | Fukushima 2020 | , , | Leave a comment

Fukushima nuclear plant owner apologizes for still-radioactive water

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TOKYO (Reuters) – The owner of the Fukushima nuclear plant, destroyed by an earthquake and tsunami more than seven years ago, said water treated at the site still contains radioactive materials that for years it has insisted had been removed.
 
Storage tanks for contaminated water are seen through a window of a building at Tokyo Electric Power Co.’s (TEPCO) Fukushima Daiichi nuclear power plant in Okuma, Fukushima, Japan, February 23, 2017.
 
The admission by Tokyo Electric Power (Tepco) could ruin its chances of releasing the water into the ocean, a move the nuclear regulator says is safe but which local fishermen oppose.
Tokyo won the bid to host the 2020 Summer Olympics more than five years ago, with Prime Minister Shinzo Abe declaring that Fukushima was “under control” in his final pitch to the International Olympic Committee.
The nearly one million tonnes of stored water at the wrecked plant, enough to fill about 500 Olympic swimming pools, still contained detectable levels of potentially harmful radioactive particles, Tepco told a government committee on Oct. 1.
Tepco apologized to the committee under the Ministry of Economy, Trade and Industry, which is looking into ways to dispose of the water.
A spokesman at Tepco confirmed the findings and the apology.
 
A 9.0-magnitude quake and tsunami in March 2011 triggered meltdowns at three of the Fukushima Daiichi plant’s six reactors, spewing radiation into the air, soil and ocean and forcing 160,000 residents to flee, many of whom have not returned.
It was the world’s worst nuclear disaster since Chernobyl 25 years earlier.
Hundreds of deaths have been attributed to the chaos of evacuations during the crisis and to the hardship and trauma refugees have experienced since then, but the government only last month acknowledged for the first time that one worker at the plant had died from radiation exposure.
Documents on the government committee’s website show that of 890,000 tonnes of water held at Fukushima, 750,000 tonnes, or 84 percent, contain higher concentrations of radioactive materials than legal limits allow.
In 65,000 tonnes of treated water, the levels of radioactive materials are more than 100 times government safety levels.
Radioactive readings of one of those isotopes, strontium-90, considered dangerous to human health, were detected at 600,000 becquerels per liter in some tanks, 20,000 times the legal limit.
Tepco has for years insisted that its purification processes remove strontium and 61 other radioactive elements from the contaminated water but leaves tritium, a mildly radioactive element that is difficult to separate from water.
 
Tritium is regularly released after dilution in normally operating nuclear plants.
“We will filter the water in the tanks one more time to bring the levels to below regulatory limits before release into the ocean if a decision is made to do so,” the Tepco spokesman said.
The water build-up has come about because Tepco must pour water over the three reactors to keep the melted uranium fuel at a safe temperature.
Groundwater flowing from the hills above the plant enters the reactor basements, where it mixes with highly radioactive debris. That gets pumped out and treated before being stored in tanks that are fast filling up.
And a costly “ice wall” is failing to keep groundwater from entering the basements, a Reuters analysis of the Tepco data showed earlier this year.
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The groundwater seepage has delayed Tepco’s clean-up and may undermine the entire decommissioning process.
Nearby residents, particularly fishermen, oppose ocean releases of the treated water because they fear it will keep consumers from buying Fukushima products.
Many countries, including South Korea and China, still have restrictions on produce from Fukushima and neighboring areas.

October 12, 2018 Posted by | Fukushima 2018 | , , | Leave a comment

Fukushima ice wall yields limited benefit for its cost

March 11, 2018
$322m barrier is less effective than lower-tech measures in fighting contamination
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Tepco has surrounded the reactors at its Fukushima Daiichi plant with a wall of frozen earth.
TOKYO — Tokyo Electric Power Co. Holdings faces the question of whether the so-called frozen soil wall built to contain contamination at its damaged Fukushima Daiichi nuclear power plant justifies its high cost.
The 1.5km barrier of frozen earth, which cost 34.5 billion yen ($322 million) to build using taxpayer money, is supposed to keep groundwater out of the plant’s four reactor buildings. Multiple reactors suffered core meltdowns following the earthquake and tsunami in March 2011. Any water that enters must undergo decontamination, though it is not possible to remove all the radioactive material the water takes up.
Tepco, as the utility is widely known, has said that the barrier has reduced the amount of new contaminated groundwater by 95 tons a day. This suggests that the wall accounts for just one-quarter of recent reductions: Around 110 tons of groundwater were contaminated daily in the three months through February, compared to roughly 490 tons daily before the frozen barrier was created. Freezing of earth around the buildings began in March 2016, and was nearly complete last November.
The utility has said a variety of external factors make those numbers difficult to compare directly, and it plans to release a more detailed analysis as soon as next week. “The frozen soil wall is working,” said Naohiro Masuda, chief decommissioning officer for the Fukushima plant. Some of the tanks to store contaminated water are rendered unnecessary, and “this is huge in monetary terms,” he said.
Others beg to differ. “It is hard to believe” the barrier is “contributing as much as it cost to build,” said Masashi Kamon, professor emeritus at Kyoto University. Japan’s Nuclear Regulation Authority has also raised questions about the barrier’s effectiveness relative to its cost.
Lower-tech measures also in place to prevent contamination, such as wells that pump water out of the ground surrounding the plant, have proven more effective than the frozen barrier. But Tepco plans to keep the wall in place, at an annual cost of more than 1 billion yen, until the groundwater contamination problem is resolved.

March 15, 2018 Posted by | Fukushima 2018 | , | Leave a comment

Fukushima Ice Wall Failing, Water Seepage Into Nuclear Reactors Still A Problem

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March 9th, 2018 by James Ayre

The “ice wall” that Tokyo Electric Power Co (Tepco) put in place a few years ago, with the intent of stopping water seepage into the basements of the Fukushima Dai-ichi nuclear plant, isn’t functioning as advertised (so to speak).
 
Going on an analysis performed by Reuters (using Tepco data), since the ice wall became “operational” — towards the end of August 2017 — an “average of 141 metric tonnes a day of water has seeped into the reactor and turbine areas.”
 
What that means is that after the ice wall was deemed to be fully operational that the flow of groundwater into the areas in question actually increased — as the previous 9 months (before August 2017) had seen an average of 132 metric tonnes a day of groundwater seepage.
 
Considering how expensive the ice wall was to put into place, and Tepco’s assurances to skeptics that the approach would be effective, this is very notable, to say the least.
 
As a result of this failure, large quantities of groundwater are continuing to flow into the basements of the Fukushima nuclear power plants, and there mingle with the extremely radioactive material present there.
 
Arguments are of course being made by Tepco officials, though, that since groundwater flows have lessened over the last few years that the ice wall is working (in conjunction with various pumps and drains), but considering the figures discussed above, effectiveness is certainly limited.
 
The company is claiming that, based on computer models, the ice wall is reducing groundwater flow into the reactors by around 95 tonnes a day, compared to 2 years ago.
 
Reuters provides more information:
 
“The groundwater seepage has delayed Tepco’s clean-up at the site and may undermine the entire decommissioning process for the plant, which was battered by a tsunami 7 years ago this Sunday. Waves knocked out power and triggered meltdowns at 3 of the site’s 6 reactors that spewed radiation, forcing 160,000 residents to flee, many of whom have not returned to this once-fertile coast.
 
“Though called an ice wall, Tepco has attempted to create something more like a frozen soil barrier. Using ¥34.5 billion ($324 million) in public funds, Tepco sunk about 1,500 tubes filled with brine to a depth of 30 meters (100 feet) in a 1.5-kilometre (1-mile) perimeter around 4 of the plant’s reactors. It then cools the brine to minus 30° Celsius (minus 22° Fahrenheit). The aim is to freeze the soil into a solid mass that blocks groundwater flowing from the hills west of the plant to the coast.”
 
It should be realized that the more groundwater seepage there is into the areas in question, the more radioactive water there is to eventually deal with — or not deal with, as may be the case.
 
To date, the radioactive water at the Fukushima site has either been lost to the wider environment or is stored in large tanks at the facility. These storage tanks now total more than a thousand, and store over 1 million tonnes of radioactive water. Tepco has warned that it will run out of space at the site to store this water by as soon as early 2021. What happens then?
 
“I believe the ice wall was ‘oversold’ in that it would solve all the release and storage concerns,” commented Dale Klein, the former head of the US Nuclear Regulatory Commission, and the head of an external committee that’s advising Tepco on safety issues, to Reuters.
 
“The hydrology of the Fukushima site is very complicated and thus the exact water flow is hard to predict, especially during heavy rains.”
 
This reality was made especially clear last October when a typhoon affected the region, and 866 tonnes a day of groundwater flowed into the nuclear reactors for the duration.
 
The Reuters coverage provides a bit more:
 
“However, a government-commissioned panel on Wednesday offered a mixed assessment of the ice wall, saying it was partially effective but more steps were needed…In addition to the building costs, the ice wall needs an estimated 44 million kilowatt hours of electricity a year to run, enough to power about 15,000 typical Japanese homes.
 
“Meanwhile, Tepco must decide how to cope with the growing volume of water stored on site. The purification process removes 62 radioactive elements from the contaminated water but it leaves tritium, a mildly radioactive element that is difficult to separate from water. Not considered harmful in low doses, tritium is released into oceans and rivers by nuclear plants around the world at various national standard levels.
 
“But local residents, particularly fishermen, oppose ocean releases because they fear it will keep consumers from buying Fukushima products. Many countries, including South Korea and China, still have restrictions on produce from Fukushima and neighboring areas.”
 
That’s not to say that such releases won’t be the eventual outcome, as they are one of the primary options now being considered by a government-commissioned task force working on the problem.
 
As far as whether the water in question actually does “only” contain radioactive tritium, that remains an open question as Tepco has yet to allow third-party testing of the store “purified” water in question. Without third-party testing, who actually knows what’s in it?
 
As a reminder here, the Fukushima nuclear disaster effectively began 7 years ago on Sunday and is quite obviously still ongoing. A vast amount of money has already been spent working to contain the nuclear material and contamination at the Fukushima site, but the reality remains that a vast amount more will have to be spent over the coming decades. The area itself will effectively remain unfit for human habitation indefinitely regardless of containment and remediation work.
 

March 14, 2018 Posted by | Fukushima 2018 | , | Leave a comment

Fukushima’s giant ice wall fails to stop water leaking into radioactive area

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March 8, 2018
A giant ice wall constructed underneath the ill-fated Fukushima Daiichi power plant in Japan is failing to prevent groundwater from seeping into it, according to a new report from Reuters.
 
The failure to contain the water is preventing clean-up teams from removing the last of the dangerous radioactive fuel, seven years after a tsunami hit the plant and triggered a catastrophic meltdown.
 
The refrigeration structure, which resembles giant ice lollies, was completed in 2016 and was an attempt to limit the amount of radioactive water created by the incident.
 
The aim is to freeze the soil into a solid mass that blocks groundwater flowing from the hills west of the plant to the coast.
 
At the time of the ice wall construction, nearly 800,000 tonnes of contaminated water was being stored in 1,000 huge industrial tanks at the site.
 
Data released from operator Tokyo Electric Power Co (TEPCO) showed that water leakage has actually got worse since the structure was turned on.
 
An average of 141 metric tonnes of water per day seeped into the reactor and turbine areas, compared to an average of 132 metric tonnes a day during the prior nine months.
 
The structures cost around 34.5 billion yen (£233m) in public funds and consist of approximately 1,500 tubes filled with brine, cooled to minus 30°C, and buried 30 metres underground.
 
“I believe the ice wall was ‘oversold’ in that it would solve all the release and storage concerns,” said Dale Klein, the former chairman of the US Nuclear Regulatory Commission and the head of an external committee advising Tepco on safety issues.
 
“The hydrology of the Fukushima site is very complicated and thus the exact water flow is hard to predict,” he said, “especially during heavy rains.”
 
Overall, Tepco says a combination of drains, pumps and the ice wall has cut water flows by three-quarters, from 490 tons a day during the December 2015 to February 2016 period to an average of 110 tons a day for December 2017 to February 2018.
 
It is hard to measure exactly how much the ice wall is contributing, Tepco officials say, but based on computer analysis the utility estimates the barrier is reducing water flows by about 95 tonnes a day compared to two years ago, before the barrier was operating.
 
However, it expects to run out of space to store the water by 2021, so the decommissioning process needs to be completed as quickly as possible.
 
In 2016, the estimate for the total cost of the clean-up operation increased to 22.6tr yen (£151bn), more than double the previous estimate.
 
According to a Greenpeace report on Fukushima, published last week, the people, towns and villages in the surrounding area are still being exposed to excessive levels of radiation. A ground-level study conducted by an international research team also found that uranium and other radioactive materials, such as caesium and technetium, were present in tiny particles released from the damaged nuclear reactors.

 

March 14, 2018 Posted by | Fukushima 2018 | , , , | Leave a comment

Experts: Fukushima Must Do More to Reduce Radioactive Water

March 7, 2018
By MARI YAMAGUCHI, Associated Press
A group of experts has concluded that a costly underground ice wall is only partially effective in reducing the ever-growing amount of contaminated water at Japan’s destroyed Fukushima nuclear plant, and that other measures are needed as well.
 
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In this Nov. 12, 2014, file photo, workers wearing protective gears stand outside Fukushima Dai-ichi nuclear power plant’s reactor in Okuma, Fukushima prefecture, northeastern Japan.
A government-commissioned group of experts concluded Wednesday, March 7, 2018 that a costly underground ice wall is only partially effective in reducing the ever-growing amount of contaminated water at Japan’s destroyed Fukushima nuclear plant, and that other measures are needed as well.
 
TOKYO (AP) — A government-commissioned group of experts concluded Wednesday that a costly underground ice wall is only partially effective in reducing the ever-growing amount of contaminated water at Japan’s destroyed Fukushima nuclear plant, and that other measures are needed as well.
The plant’s operator, Tokyo Electric Power Co., says the ice wall has helped reduce the radioactive water by half. The plant also pumps out several times as much groundwater before it reaches the tsunami-damaged reactors via a conventional drainage system using dozens of wells dug around the area.
The groundwater mixes with radioactive water leaking from the damaged reactors.
The panel agreed Wednesday that the ice wall helps, but said it doesn’t completely solve the problem. Panel members suggested that additional measures be taken to minimize the inflow of rainwater and groundwater, such as repairing roofs and other damaged parts of the buildings.
The 1.5-kilometer (1-mile) coolant-filled underground structure was installed around the wrecked reactor buildings to create a frozen soil barrier and keep groundwater from flowing into the heavily radioactive area. The ice wall has been activated in phases since 2016. Frozen barriers around the reactor buildings are now deemed complete.
On Wednesday, TEPCO said the amount of contaminated water that collects inside the reactor buildings was reduced to 95 metric tons per day with the ice wall, compared to nearly 200 tons without one. That is part of the 500 tons of contaminated water created every day at the plant, and the other 300 tons were pumped out via wells, treated and stored in tanks.
In addition to the 35 billion yen ($320 million) construction cost funded by taxpayers’ money, the ice wall needs more than 1 billion yen ($9.5 million) annually in operating and maintenance costs. Critics have been skeptical about the ice wall and suggested that the greater use of wells — a standard groundwater drainage system — would be a cheaper and more proven option.
The plant has been struggling with the ever-growing water — only slightly contaminated after treatment — now totaling 1 million tons and stored in 1,000 tanks, which take up significant space at the complex, where a decades-long decommissioning effort continues. Officials say they aim to further reduce the amount of contaminated water in the reactor buildings before starting to remove melted fuel in 2021.

 

March 7, 2018 Posted by | Fukushima 2018 | , , | Leave a comment

Japan undecided on what to do with 1 million tonnes of radioactive water at Fukushima plant

February 2, 2018
Key points:
The rate of contaminated water reaching the facility has slowed, but is still increasing
There are now more than 1,000 tanks of contaminated water at the site
One controversial option for dealing with the water includes decontaminating it as much as possible and then gradually releasing it into the ocean
 
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Storage tanks for contaminated water at Fukushima nuclear plant
The water is being stored in hundreds of large and densely packed tanks at the plant.
 
Japanese Government officials have not figured out what to do with more than 1 million tonnes of radioactive water sitting at the site of the crippled Fukushima nuclear power plant.
Just days shy of the seventh anniversary of the nuclear disaster, Tokyo Electric Power Company (TEPCO) revealed it successfully slowed the rate of contaminated water reaching the reactor facilities, but the amount was still increasing.
“A few years a go [the radioactive water was increasing by] 400 tonnes per day, but the increase per day has now gone down to around 100 tonnes per day,” said Naohiro Masuda, TEPCO’s chief decommissioning officer.
“A few years ago we had to create one new tank every two or three days but now we need to increase one new tank every seven to 10 days, so in that sense we think it is progress, to a certain degree, in the sense it is a more stabilised situation,” he said.
There are more than 1,000 tanks of contaminated water now at the site — and Government authorities have still not decided what to do with the water.
 
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Aerial view of tanks of contaminated water at the Fukushima nuclear plant
Experts want a gradual release, but if the tanks break the water would slosh out.
 
Ice wall of limited effect
TEPCO revealed earlier this week that its underground frozen soil wall — what was expected to be the main defence against groundwater contamination — had only had a limited effect.
The 1.5-kilometre-long barrier is designed to keep groundwater from flowing into reactor buildings that were damaged by the disaster.
The wall cost more than $US300 million to build and costs $US10 million to operate.
Mr Masuda said it was important to note that the combination of the company’s measures to prevent contamination meant that the situation was less volatile overall.
So while the level of contaminated water is still increasing — albeit at a slower rate — the Japanese Government is yet to agree on what to do with it.
One controversial option includes decontaminating the water as much as possible and then gradually release it into the ocean.
Experts advising the Government have urged a gradual release of the water to the nearby Pacific Ocean.
Treatment can remove all the radioactive elements except tritium, which they say is safe in small amounts.
But local fishermen have balked at the idea, fearing a devastating impact to the reputation of their produce.
Satoru Toyomoto from the Japanese Ministry of Economy, Trade and Industry said a Government sub-committee was still considering its options.
“You may think after as many as seven years [this should be decided], but we have done our utmost and we have done all possible things and we have finally come to a stage where we can consider this,” he said.
“After the accident occurred [in 2011] it was like a field hospital on a battlefield — but finally we have reached a situation where we can calmly think about the long-term future.
“A taskforce two years ago considered various options including geological disposal, vaporisation, burial underground, hydrogen release or release into the sea.
“Of those five options, we are trying to make a comprehensive assessment looking at options, but also reputational measures.”

March 2, 2018 Posted by | Fukushima 2018 | , , | Leave a comment

TEPCO defends Fukushima ‘ice wall,’ but it is still too porous

march 2 2018 icewall still porous.jpg
Rows of tanks holding contaminated groundwater are seen at the Fukushima No. 1 nuclear power plant in February.
 
The “frozen soil wall” erected around the crippled reactor buildings at the Fukushima No. 1 nuclear power plant at huge taxpayer expense appears limited in keeping groundwater from flowing in.
Tokyo Electric Power Co., which operates the plant, said March 1 that 95 tons of radioactive water has been reduced a day on average between December and early February because of the underground barrier.
“Contaminated groundwater was cut in half due to the wall,” a TEPCO official said.
TEPCO estimated that the volume of polluted groundwater would have amounted to about 189 tons if the ice wall had not been in place during that period.
The utility also said the amount of polluted groundwater was reduced by about 400 tons a day now due to combined measures, such as the wall and wells pumping up water, compared with before such measures were taken.
But Toyoshi Fuketa, chairman of the Nuclear Regulation Authority, has insisted that the wells, not the wall, are the “key” to controlling the groundwater, voicing skepticism about the role of the ice wall.
The utility is proceeding with work to reinforce the wells.
The 34.5 billion yen ($322 million) frozen soil wall project began in 2014 to lay out the 1,500-meter-long underground wall around the No. 1-4 reactor buildings.
A large number of pipes were inserted to a depth of 30 meters to circulate liquid with a temperature of minus 30 degrees through them to freeze the surrounding soil.
It was designed to prevent groundwater from flowing into the plant and mixing with highly radioactive water in the basements of the buildings.
TEPCO’s recent assessment of the effectiveness of the frozen soil wall came after temperatures around the structure dropped to below zero following work that began last August to freeze the remaining final section of the wall.
But experts pointed out that the utility’s assessment is based on figures only when there was little rain.
The water volume rose to 1,000 tons or so a day in late October when two typhoons struck the area.
TEPCO believes that the surge at that time is largely attributable to the downpours from the typhoons.
Heavy rain accumulated in the basement after flowing down holes in the ceilings caused by hydrogen explosions during the 2011 triple meltdown.
It costs more than 1 billion yen a year in electricity fees to keep the wall frozen.
The company plans to remove all the groundwater from the buildings by 2020 so that it can begin work to decontaminate the facilities later.

March 2, 2018 Posted by | Fukushima 2018 | , | Leave a comment

TEPCO: Frozen soil wall effect limited

 

2018/03/01
Tokyo Electric Power Company, or TEPCO, says an underground frozen soil wall around its Fukushima Daiichi nuclear plant has had a limited effect in reducing groundwater contamination.
 
The 1.5-kilometer-long barrier is designed to keep groundwater from flowing into reactor buildings that were damaged by the March 2011 earthquake, tsunami and nuclear meltdowns.
 
The wall was expected to be the main defense against groundwater contamination, as about 500 tons of water was being tainted daily by radioactive substances.
 
TEPCO officials on Thursday estimated the amount of new contaminated water to have decreased by about 95 tons a day from before the wall was built.
They said the estimate is based on 3 months of data including that from before and after the wall was almost completed last November.
 
TEPCO had introduced a so-called sub-drain system for pumping up water from wells dug around the buildings.
 
The officials estimated that the 2 measures resulted in a decrease of 380 tons of tainted groundwater a day, suggesting the wall’s effectiveness is limited and lower than that of the drain method.
 
The government plans to ask experts to look into whether the utility’s estimate is accurate.
 
Public funds worth over 300 million dollars have been used to build the wall. Its annual operating cost exceeds ten million dollars.
icewall march 1 2018.jpg

March 1, 2018 Posted by | Fukushima 2018 | , , , | Leave a comment

Fukushima ‘ice wall’ linchpin not living up to high hopes

26 nov 2017 icewall
Although 34.5 billion yen ($309 million) in taxpayer money has funded an “ice wall” to keep out groundwater from the Fukushima No. 1 nuclear power plant site, the frozen barrier may not be meeting hopes and expectations.
In particular, the wall has been vulnerable to heavy rain brought by typhoons.
Reducing the volume of radiation-contaminated water is vital to proceeding with the removal of melted fuel from the reactors at the Fukushima No. 1 plant so it can be decommissioned.
But officials of Tokyo Electric Power Co., the operator of the plant, are still not completely sure if the ice wall is performing as designed.
Heavy rain appears to pose a major problem because the ice wall has so far proved incapable of stopping groundwater when typhoons have passed near the plant.
In theory, the ice wall should serve as a dam to prevent groundwater from the mountainside of the plant from flowing into the reactor buildings.
The total length of the wall is about 1,500 meters, and the wall surrounds the reactor and turbine buildings of four reactors at the No. 1 plant. Pipes have been buried about 30 meters deep at one-meter intervals.
26 nov icewall 2.png
Liquid at temperatures of minus 30 degrees have been poured into the pipes to freeze the surrounding ground. Freezing of the final section of the wall began on Aug. 22, but TEPCO officials on Nov. 22 still stopped short of offering an assessment of whether the ice wall was actually working as planned.
Utility officials have said that after about two months, ground temperatures where the freezing had begun have fallen below 0 degrees.
The estimated volume of groundwater that has leaked into the reactor and other buildings was 190 tons a day at the start of 2016, but it had decreased to 110 tons a day by early October.
However, the situation changed dramatically when two typhoons passed by in late October.
The groundwater level rose rapidly and the average daily flow of groundwater into the building basements for October was estimated to be 310 tons. That was close to the 400 tons that was flowing into the building basements before any measures were implemented to deal with the contaminated water.
There was no realistic expectation of building a ice wall that would keep out all groundwater because the pipes had to be buried in a way that would avoid underground piping from the reactors that were already in place. That meant there were underground portions that could not be frozen.
Masashi Kamon, a professor emeritus at Kyoto University who specializes in environmental geotechnics, said TEPCO should have considered a number of measures to stem the flow of groundwater from the long-term perspective of eventually removing the melted fuel from the reactors.
Another measure that is receiving more attention of late is pumping up groundwater from the 42 wells located around the reactor buildings and releasing it into the ocean. TEPCO plans to double the number of pumps and processing capacity of decontamination facilities by early 2018.
But other measures will likely have to be considered before work can begin to remove melted fuel from the reactor cores. The first step would be to remove as much as possible the highly radioactive water that remains in the reactor building basements. Such water poses a huge risk to the workers who will have to enter the buildings to remove the fuel.
Toyoshi Fuketa, chairman of the Nuclear Regulation Authority, said the ice wall was a measure implemented when the situation was much more serious, but that now is the time for calmer consideration about whether that investment of time and money was the proper one.

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

Frozen soil wall nearly complete; NRA still doubts effect

ice wall 7 nov 2017.jpg
A construction project to create frozen soil walls that encircle the ground beneath Tokyo Electric Power Company Holdings Inc.’s disaster-hit Fukushima No. 1 nuclear power plant is nearly finished.
Although TEPCO insists that the inflow of groundwater beneath the reactor buildings has been reduced, some members of the Nuclear Regulation Authority are skeptical about the project’s effectiveness. With ¥34.5 billion of public funds being spent on this project, the centerpeice of countermeasures for contaminated water, its cost-effectiveness is being carefully watched.
The project entails building a 1.5-kilometer-long frozen soil wall encircling the Nos. 1 to 4 reactors, with 1,568 pipes buried to a depth of about 30 meters below ground and coolant running through the pipes at minus 30 C to chill the soil.
The process is expected to prevent groundwater from flowing into the contaminated, highly radioactive underground water at such sites as the reactor buildings, and to avoid an increase of contaminated water.
The project began in March last year, and operations to freeze the final section, about seven meters wide, on the mountain side began in August this year.
The temperature of the underground soil has remained below zero, except for a part close the surface that is affected by outdoor air, meaning the project to create the 30-meter-deep walls is almost complete.
According to TEPCO’s assessment, before the project started, about 400 tons of groundwater was flowing into the ground underneath the reactor buildings and other sites daily.
TEPCO had initially calculated that the daily inflow of groundwater could decrease to dozens of tons once the walls were installed. However, between April and September the inflow per day was between 120 tons and 140 tons, and in October it was around 100 tons. That the amount of inflow has decreased in stages as the soil freezing progressed seems to prove that the project has been effective to a certain extent. However, it is unclear if the inflow will decrease further in the future.
In parallel with the frozen soil wall project, TEPCO dug about 40 subdrain wells to pump up groundwater before it flows into the reactor buildings. It also reinforced measures to prevent rainwater from soaking into the ground by paving 1.33 million square meters of surface.
In the NRA view, those measures must also contribute greatly to reducing the inflow, casting doubt on the frozen soil walls project by saying the effect of them alone may be limited. The agency has become distrustful of TEPCO and urged the company to verify the effects.
Hiroshi Miyano, visiting professor at Hosei University specializing in system safety, said: “There is sure to be a part that doesn’t freeze completely, and it’s impossible to reduce the inflow to zero. TEPCO must continue applying this measure in tandem with draining the nearby wells for a while.”

November 9, 2017 Posted by | Fukushima 2017 | , | Leave a comment