Fukushima ice wall yields limited benefit for its cost

March 11, 2018
$322m barrier is less effective than lower-tech measures in fighting contamination
march 11 2018-ice-wall_article_main_image.jpg
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.

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



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.

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

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.

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.
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.


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
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.
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.”


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

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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.

TEPCO: Frozen soil wall effect limited


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.