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Japan’s ‘Hail Mary’ at Fukushima Daiichi: An Underground Ice Wall

Japan’s ‘Hail Mary’ at Fukushima Daiichi: An Underground Ice Wall thumbnail

FUKUSHIMA DAIICHI NUCLEAR POWER STATION — The part above ground doesn’t look like much, a few silver pipes running in a straight line, dwarfed by the far more massive, scarred reactor buildings nearby.

More impressive is what is taking shape unseen beneath: an underground wall of frozen dirt 100 feet deep and nearly a mile in length, intended to solve a runaway water crisis threatening the devastated Fukushima Daiichi Nuclear Power Station in Japan.

Officially named the Land-Side Impermeable Wall, but better known simply as the ice wall, the project sounds like a fanciful idea from science fiction or a James Bond film. But it is about to become a reality in an ambitious, and controversial, bid to halt an unrelenting flood of groundwater into the damaged reactor buildings since the disaster five years ago when an earthquake and a tsunami caused a triple meltdown.

Built by the central government at a cost of 35 billion yen, or some $320 million, the ice wall is intended to seal off the reactor buildings within a vast, rectangular-shaped barrier of man-made permafrost. If it becomes successfully operational as soon as this autumn, the frozen soil will act as a dam to block new groundwater from entering the buildings. It will also help stop leaks of radioactive water into the nearby Pacific Ocean, which have decreased significantly since the calamity but may be continuing.

However, the ice wall has also been widely criticized as an expensive and overly complex solution that may not even work. Such concerns re-emerged this month after the plant’s operator announced that a section that was switched on more than four months ago had yet to fully freeze. Some also warn that the wall, which is electrically powered, may prove as vulnerable to natural disasters as the plant itself, which lost the ability to cool its reactors after the 45-foot tsunami caused a blackout there.

The reactor buildings are vulnerable to an influx of groundwater because of how the operator, Tokyo Electric Power Co., or Tepco, built the plant in the 1960s, by cutting away a hillside to place it closer to the sea, so the plant could pump in water more easily. That also put the buildings in contact with a deep layer of permeable rock filled with water, mostly rain and melted snow from the nearby Abukuma Mountains, that flows to the Pacific.

The buildings managed to keep the water out until the accident on March 11, 2011. Either the natural disasters themselves, or the explosive meltdowns of three of the plant’s six reactors that followed, are believed to have cracked the buildings’ basements, allowing groundwater to pour in. Nearly 40,000 gallons of water a day keep flooding into the buildings.

Once inside, the water becomes highly radioactive, impeding efforts to eventually dismantle the plant. During the accident, the uranium fuel grew so hot that some of it is believed to have melted through the reactor’s steel floors and possibly into the basement underneath, though no one knows exactly where it lies. The continual flood of radioactive water has prevented engineers from searching for the fuel.

Since the accident, five robots sent into the reactor buildings have failed to return because of high radiation levels and obstruction from debris.

Pipes containing coolant are being used to help create an underground ice wall to try to stop contaminated water from leaking. Ko Sasaki for The New York Times

The water has also created a waste-management nightmare because Tepco must pump it out into holding tanks as quickly as it enters the buildings, to prevent it from overflowing into the Pacific. The company says that it has built more than 1,000 tanks that now hold more than 800,000 tons of radioactive water, enough to fill more than 320 Olympic-size swimming pools.

On a recent visit to the plant, workers were busily erecting more durable, welded tanks to replace the temporary ones thrown up in a hurry during the early years after the accident, some of which have leaked. Every available patch of space on the sprawling plant grounds now appears to be filled with 95-foot tanks.

“We have to escape from this cycle of ever more water building up inside the plant,” said Yuichi Okamura, a general manager of Tepco’s nuclear power division who guided a reporter through Fukushima Daiichi. About 7,000 workers are employed in the cleanup.

The ice wall is a high-technology bid to break that cycle by installing what might be the world’s largest freezer. Pipes almost 100 feet long have been sunk into the ground at roughly three-foot intervals, and filled with a brine solution supercooled to minus 30 degrees Celsius, or minus 22 Fahrenheit. Each pipe is supposed to freeze a column of soil about a foot and a half in radius, large enough to reach the ice column created by its neighboring pipes and form a seamless barrier.

Engineers with the wall’s builder, the construction giant Kajima Corp., estimate that it will take about two months for the soil around a pipe to fully freeze. Solidifying the entire wall, which consists of 1,568 such underground pipes, will require 30 large refrigeration units and consume enough electricity to light more than 13,000 Japanese homes for a year.

Fukushima Five Years After Nuclear Disaster

Five years after an earthquake and tsunami devastated the northeast Japanese coast, Japan has not fully recovered.

The technique of using frozen barriers to block groundwater has been used to build tunnels and mines around the world, but not on this scale. And certainly not on the site of a major nuclear disaster.

Since the start, the project has attracted its share of skeptics. Some say buried obstacles at the plant, including tunnels that linked the reactor buildings to other structures, will leave holes in the ice wall, making it more like a sieve. Others question why such an exotic solution is necessary when a traditional steel or concrete wall might perform better.

Some call the ice wall a flashy but desperate gambit to tame the water problem, after the government and Tepco were initially slow to address it. Adding to the urgency is the 2020 Olympics, which Prime Minister Shinzo Abe of Japan helped win for Tokyo three years ago by assuring the International Olympic Committee that the water troubles at Fukushima Daiichi were under control.

Supporters and skeptics alike will soon learn if that gambit will succeed. After two years of work, Kajima finished installing the pipes and refrigerator units to create the ice wall in February. At the end of March, it switched on part of the ice wall for the first time — roughly half a mile that runs between the reactor buildings and the Pacific. Most of the other, uphill side of the wall was activated in mid-June.

One of the approximately 7,000 workers being employed in the cleanup of Fukushima Daiichi, which was devastated by an earthquake and a tsunami in 2011. Ko Sasaki for The New York Times

Kajima is freezing the wall in stages under orders from the Nuclear Regulation Authority, Japan’s nuclear watchdog. The authority is concerned that cutting off the groundwater too suddenly might lead to a reversal of flows, causing the radioactive water accumulated inside the reactor buildings to start pouring out into the surrounding soil, possibly reaching the Pacific. It has told Kajima to leave a half-dozen “gateways” in the uphill side that will not be closed until much of the contaminated water is drained from the buildings.

This month, Tepco told the nuclear agency that the seaside segment of the ice wall had frozen about 99 percent solid. It says a few spots have failed to solidify because they contain buried rubble or sand left from the plant’s construction a half-century ago, which now allow groundwater to flow through so quickly that it will not freeze.

Tatsuhiro Yamagishi, a spokesman for Tepco, said the company was trying to plug these holes in the ice wall with quick-drying cement. “We have started to see some progress in temperature decrease,” he said.

Even if the cement helps make the ice wall watertight, skeptics question how long it can last. They point out that such frozen barriers are usually temporary against groundwater at construction sites. They say the brine solution used to chill the pipes is highly corrosive, which could make them break or leak. It is also unclear whether the system could break down under the stresses of operating in a high-radiation environment where another earthquake could lead to another power loss.

“Why build such an elaborate and fragile wall when there is a more permanent solution available?” said Sumio Mabuchi, a former construction minister who has called for building a slurry wall, a trench filled with liquid concrete that is commonly used to block water.

Workers must wear protective gear while inside the plant. Ko Sasaki for The New York Times

Isao Abe, a Kajima engineer overseeing the ice wall, said his company had made the wall more durable by installing underground pipes that are easy to replace if they corrode. He also said the ice wall was self-sealing, meaning that if another earthquake caused cracks, any incoming water would freeze right away, restoring the wall. He also said it would take months for the wall to thaw, giving engineers ample time to restore power even if the plant has another outage.

Mr. Abe said the wall was intended to operate until 2021, giving Tepco five more years to find and plug the holes in the reactor buildings, though skeptics say this difficult task will require more time. Mr. Abe also pointed out that the ice wall was part of a broader strategy for containing the radioactive water. Before installing the ice wall, Kajima also built a conventional steel wall underground along the plant’s border with the Pacific last year.

Tepco says that wall has already stopped all measurable leaks of radioactive materials into the sea. However, some scientists say that radioactive water may still be seeping through layers of permeable rock that lie deep below the plant, emptying into the Pacific far offshore. They say the only way to eliminate all leaks would be to repair the buildings once and for all.

Even if the ice wall works, Tepco will face the herculean task of dealing with the huge amounts of contaminated water that have accumulated. The company has installed filtering systems that can remove all nuclear particles but one, a radioactive form of hydrogen known as tritium. The central government and Tepco have yet to figure out what to do with the tritium-laced water; proposals to dilute and dump it into the Pacific have met with resistance from local fishermen, and risk an international backlash.

For now, the only visible sign that the freezing has begun are silver-dollar-size patches of ice that have formed on top of the aboveground, silver pipes. At one spot, the No. 4 reactor building loomed, an enormous cube six stories tall with concrete sides that showed large gashes left by the tsunami.

“The water is here, just three meters beneath our feet,” said Mr. Okamura, the Tepco general manager, who stood near the pipes wearing a white protective suit, goggles and a surgical mask. “It still flows into the building, unseen, without stopping.”

NY Times



34 Comments on "Japan’s ‘Hail Mary’ at Fukushima Daiichi: An Underground Ice Wall"

  1. peakyeast on Tue, 30th Aug 2016 8:00 am 

    I am not sure…

    After all this time leaking into the ocean: Are they trying to keep out the radioactive substances from the ocean from seeping in or the opposite?

    :-p

  2. ghung on Tue, 30th Aug 2016 8:14 am 

    When the foundations of dams begin to leak, they pump grout into the ground at high pressure. Wondering if they’ve considered that.

  3. penury on Tue, 30th Aug 2016 9:44 am 

    You know that things are beyond repair when even ideas which have been shown to be impractical are used because the predicament is continuing. Ice walls are about as much use as two fans to provide cooling.

  4. Leslie Corrice on Tue, 30th Aug 2016 11:05 am 

    This article is fraught with mistakes. For example, the re-solidified fuel with unit #2 was found more than a month ago by Muon tomography. So much for the statement ” During the accident, the uranium fuel grew so hot that some of it is believed to have melted through the reactor’s steel floors and possibly into the basement underneath, though no one knows exactly where it lies.” Also, the water build-up has absolutely nothing to do with trying to identify the location of the re-solidified fuel in the other two units. This is the tip of the iceberg of incorrect statements.

  5. Anonymous on Tue, 30th Aug 2016 12:04 pm 

    Fukushima ice wall = epic fail (In the making)

  6. HARM on Tue, 30th Aug 2016 1:20 pm 

    Well, a magic ice wall is working pretty well in Game of Thrones, so hey…

  7. Neil Farbstein on Tue, 30th Aug 2016 1:21 pm 

    It will take a new nuclear plant to provide electricity to keep that ice wall solid.

  8. Luigi on Tue, 30th Aug 2016 1:21 pm 

    China Syndrome in Japan .

  9. Neil Farbstein on Tue, 30th Aug 2016 1:23 pm 

    They should use the artificial permafrost as an opportunity to dig a cement wall next to the frozen parts, inside the perimeter of the ice wall.

  10. Mike on Tue, 30th Aug 2016 2:23 pm 

    Something similar was done in the USA, for different reasons in the 1980s.

    I don’t remember the exact state/power plant.

    But I do remember working on the Singer-Link simulator (at that time we built full-scale computer controlled simulators to train operators how to run a specific nuclear power plant).

    In any event, a nuke power plant was planned in the mid-west region of the USA, very near the Canadian boarder (maybe it was Wisconsin?).

    The main problem at that time was that the heat generated by all of the curing concrete had started to thaw out the underlying permafrost in that area. Hence the whole entire concrete base platform supposed to support the reactor plant started to “tilt”.

    I don’t know if that reactor power plant ever got built/completed, but I do remember being amazed by the follow-on engineering “fix” to pump cold fluids through pipes into the ground to re-freeze the permafrost to support the reactor base-plate concrete platform.

    I left Singer-Link shortly afterwards to work on satellite ground system stations. I was a EE at that time, not an ME. But I can still remember thinking, “Who in the hell came up with such a dumb idea?”

    Oh well.

    Mike

  11. Ron on Tue, 30th Aug 2016 2:55 pm 

    It’s actually not as far-fetched of an approach as it may seem:

    A similar approach was used in order to create temporary access shafts to the Deep Tunnel project in Milwaukee. Refrigerant pipes were drilled and installed in long, pipe-like rings. Once the ground was frozen, the center could be dug/drilled-out with the frozen ground/soil serving as a reinforced tunnel, preventing cave-ins.

    Depending upon the type of soil – freezing it can produce a material that is nearly as strong as concrete, and quite possibly a bit more flexible, which could make it earthquake-resistant (an important factor in the land of the Rising Sun…) If the ground cracks, any water that flows-into the cracks would re-freeze, making the system “self-healing”.

    I remember watching a construction crew try to bust-up a frozen chunk of clay soil in Green Bay – about 6 feet square by 3 feet thick (it was a C-O-L-D Winter) with a large hydraulic excavator. Ramming it repeatedly with the teeth on the bucket only chipped it…

    They’ll just need to ensure that there is redundancy in the refrigeration equipment and in the power source to that equipment, so that even with several failed units and/or units under maintenance – the remaining units can literally “keep things chilled”…

  12. arkieguide on Tue, 30th Aug 2016 3:03 pm 

    I have been involved with construction in area of permafrost – we drove steel H beam piles 90 feet deep into the ground, many of them, then built a large structure
    ( concrete & steel ) over the pilings. No tilt. In the case of japan – a better idea was to drive inner locking sheet piling to 90 are 100 foot. Pour concrete to the piling, then dig a trench up stream from the plant to divert the water.

  13. Joseph M. Price, M.D. on Tue, 30th Aug 2016 3:20 pm 

    The “nuclear power plant in the midwest” whose reactor base-plate platform “started to tilt” was the one in Midland, Michigan on Saginaw Bay of Lake Huron. It had nothing to do with permafrost, which does not exist here in Michigan or in Wisconsin. It was just a matter of rotten engineering, the base material was not sufficiently firm,the pilings not deep enough to reach any stone layer. The “nuclear” plans had to be scrapped, and the plant was finished as a regular, fossil fuel plant–thank heavens, because I and my family live directly downwind from Midland.

  14. Jones the secret nulcear power plant plumber on Tue, 30th Aug 2016 4:18 pm 

    I was there, in the thick of the radiation. It’s all a loss. The pictures you see are not from that area. There are dead worker’s decaying bodies everywhere. It’s like living in hell without the fire.
    Just silent, radiation permeating everything.
    The ‘leaking’ has not and will not be ‘contained’. They are hiding the truth only trying to keep everyone from juicing their guts into an adult diaper.
    It’s all a loss, you are doomed. Stick your head into the sand and pray to the mother earth to eat you before the radiation poisons you into oblivion.
    Just kidding…I love the smell of Japanese radiation in the morning.

  15. Andres Cano on Tue, 30th Aug 2016 4:28 pm 

    They probably could not use a grout (cement-clay mixture) wall because a grout wall is only rated not to leak if the hydraulic head (water pressure) is below a specific pressure. If the head is above that level the wall will leak badly. Even the ice wall will leak but the leakage rate will be far less than what they are generating. After they decommission the reactor the soil can be excavated so the wall will not be necessary. Alternately a permanent wall keyed into a bottom clay or bedrock (if one is present?) can be built after decommissioning. Unfortunately, decommissioning should take 30-50 years.

  16. i1 on Tue, 30th Aug 2016 7:56 pm 

    I don’t think driving piles anywhere near those cooling ponds is such a good idea.

  17. ghung on Tue, 30th Aug 2016 8:22 pm 

    Andres Cano said; “They probably could not use a grout (cement-clay mixture) wall because a grout wall is only rated not to leak if the hydraulic head (water pressure) is below a specific pressure.”

    So remove that pressure. Can’t be more problematic than trying to keep the ground frozen for 50 years. Drill a bunch of wells and put an array of solar sub pumps down the holes…. or give the water somewhere easier to go; anywhere besides the plant.

    Sounds like a lot of that water is coming from far enough away that there are plenty of opportunities for intervention.

  18. Go Speed Racer on Tue, 30th Aug 2016 10:46 pm 

    What a phucking waste of money.
    I already said how to solve this.
    Go to the fireworks stand.
    Buy one (qty 1) hydrogen fusion bomb. The really big one.
    Stick it right in-between reactor buildings #3 and #4.
    Light fuse, and get away.
    Ker-blamo, problem solved, and it even swept your driveway clean.
    Wait a few years for the lagoon to stop glowing, and you can run your speed boat around in the pretty blue water.

    And excellent revenue selling tickets. To people in airplanes, people on boats, people further back in the mountains.

    Oh, the fallout. Wait til its blowing towards North Korea. Still the best solution, definitely. Not a single thing left. Good as new real estate, ready for somebody’s dream home.

  19. Go Speed Racer on Tue, 30th Aug 2016 10:48 pm 

    Aren’t the Japanese a little bit pissed, the USA has nuked them 3 times now.

  20. Apneaman on Wed, 31st Aug 2016 1:06 am 

    The Japanese have more than recovered their losses with the revenue from Godzilla movies, licensing and merchandising over the last 60 years. No nuking no Godzilla, so in the words of Madeleine Albright, I’d say “it was worth it”.

    “With the nuclear bombings of Hiroshima and Nagasaki and the Lucky Dragon 5 incident still fresh in the Japanese consciousness, Godzilla was conceived as a metaphor for nuclear weapons.[17]”

    https://en.wikipedia.org/wiki/Godzilla

    Me, I’m more of a Mothra kinda fella.

    https://www.youtube.com/watch?v=T65rW_SIzg0

  21. John Doe 68 on Wed, 31st Aug 2016 1:37 am 

    Nothing to see here. There was NO accident. ALL the reactors are working just fine. Just ignore the little man behind the curtain.

    It’s all smoke and mirrors. Really. There is NO RADIATION LEAKING AT OR NEAR THE SITE.

  22. Go Speed Racer on Wed, 31st Aug 2016 3:05 am 

    Nice. An the generators are still producing full power. Don’t have to nuke it after all.

    With all the nuclear fallout, we could make super mutated giant hamsters, that run on big 7 foot diameter hamster wheels. Generate some serious power that way. Make the floor shake.

  23. DCW on Wed, 31st Aug 2016 3:41 am 

    Why is this article appearing now? Tepco recently admitted that the ice wall had failed. (This was a no-brainer from the start.)

  24. Kenz300 on Wed, 31st Aug 2016 1:23 pm 

    The cost of this nuclear power disaster continues to climb……… and the poison continues to enter the environment…….

    The world needs to learn some lessons from the Chernobyl and Fukishima disasters……..the costs of these disasters continue to rise every year…..

    Wind and solar are safer, cheaper and cleaner options for generating electricity…….

  25. Bob on Wed, 31st Aug 2016 2:21 pm 

    I used to think of Japan as a capable, intelligent engineering power. I was wrong.

  26. Dredd on Wed, 31st Aug 2016 3:09 pm 

    They are trying for first place in the pollution of the oceans (Unprecedented In A Thousand Years).

  27. Go Speed Racer on Wed, 31st Aug 2016 5:50 pm 

    Hi Bob, just that it was 6 junky GE reactors we sold them.

    However their own Japanese bureaucracy failed to flood proof the Diesel engines. It was known by workers who predicted the problem. Of course the management solves problems like that, by firing anybody who predicts there will be a problem.

    Let’s say we clean up Fukushima by vaporizing the site, with atomic bomb between buildings 3 and 4. At that point, we will have nuked Japan 4 times. This could be our payback, for their discontinuing all the silver Pioneer stereo gear, in the 1970’s.

  28. makati1 on Wed, 31st Aug 2016 7:18 pm 

    bob, I think japan is still an intelligent engineering power, but as in most countries, money makes the decisions. I can hear the discussion in the board room now…

    “What is the chance that those generators will be flooded at that location?”

    Reply: “Maybe once in 100 years.”

    “How much would it cost to raise them?”

    Reply: “Maybe $10,000 each.”

    “All who say, ‘let them where they are’ say ‘Ay’. ( All but the engineer say ‘Ay’) “Well boys, we just saved another $70,000 on this project.”

    Happens every day in the capitalist world, be it nuke plants, F35 fighter jets, etc. It’s ALL about money.

  29. Go Speed Racer on Wed, 31st Aug 2016 11:49 pm 

    Ya well those drunken fraternity boy business turds are making a whole lot of money, now they they turned their 6 reactor power station into the worlds biggest waste dump. Hooray for the infinite brilliance, of the drunken billionaire fraternity boy managers, so busy snorting cocaine off the hookers tits on their yacht, to notice the engineers are actually right.

  30. Gabriel on Thu, 1st Sep 2016 1:28 am 

    Radiation is higher on a commercial plane then is in Fukushima,

  31. Gabriel on Thu, 1st Sep 2016 1:34 am 

    Radiation is higher on a commercial plane than is in Fukushima, people need to take a Geiger and learn how to use it, I am shocked to see the comments from Americans, seams schools there teach nothing, average person does not even know what radiation is, or that uranium of the size of a coke can, would provide for electricity needs of a person for all his life, how about Ramsar Iran, where people always lived and has higher radiation than Chernobyl, now I bet some hippies will say that is ” natural radiation” … we are doomed, the public schools created a population than can be brainwashed and they follow like sheep, and get robbed from their money by the fossil fuel producers, is sad.

  32. peakyeast on Thu, 1st Sep 2016 2:42 am 

    Gabiel I believe we all know your argument here. It has been displayed many times.

  33. drwater on Thu, 1st Sep 2016 11:19 pm 

    This whole freezing solution seems like somebody’s ridiculous sci-fi solution to a basic problem taken care of all over the world using interceptor drains and wells. It’s easy – intercept the groundwater before it gets to the site and gets contaminated.

  34. Kenz300 on Fri, 2nd Sep 2016 9:49 am 

    Nuclear energy is too dangerous and too costly…..

    Radiation Along Fukushima Rivers Up to 200 Times Higher Than Pacific Ocean Seabed

    http://www.ecowatch.com/radiation-fukushima-rivers-200-times-higher-than-pacific-ocean-seabed-1937971722.html


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