Fukushima’s underground ice wall keeps nuclear radiation at bay — CNET

” The intricate network of small metal pipes, capped off by six-foot-high metal scaffolding, shouldn’t stand out amid the numerous pieces of industrial equipment littered throughout the Fukushima Daiichi Nuclear Power Plant. After all, it’s a power plant.

I take a closer look, and notice spheres of ice perched upon the smaller pipes, which line the center of the structure. The facility sits at the water’s edge, and there’s a brisk breeze blowing through.

But not that brisk.

It turns out, coolant is running through the pipes, freezing the soil below and creating an impermeable ice wall that’s nearly 100 feet deep and a mile long, encircling the reactors.

It’s like a smaller-scale subterranean version of the Wall in Game of Thrones, but instead of keeping out White Walkers and wights, this line of defense keeps in a far more realistic danger: radioactive contaminants from melted-down reactors that threaten to spill into the water by Fukushima Daiichi.

Daiichi is the site of the worst nuclear disaster, which happened after an earthquake hit on March 11, 2011, triggering a tsunami that devastated the facility. Two 50-foot-high waves knocked out the power generators that were keeping three of the six reactors’ fuel rods cool, triggering explosions and meltdowns that forced more than 160,000 people to flee their homes. Many of them still haven’t returned.

I came to Fukushima to check out the robots tasked with the near-impossible task of cleaning up Fukushima Daiichi. While here, I encountered this underground wall of ice.

The structure, which cost roughly $300 million, paid for by public funds, serves as critical protection, defending the Fukushima area from one of the most radioactive hotspots in the world. While Tokyo Electric Power Co., also known as Tepco, struggles to find a way to remove radioactive material from the facility – a process the government estimates could take more than four decades – the more immediate concern is what to do with the contaminated water leaking out from the facility.

One of the solutions has been to put up (down?) this underground ice wall, which prevents much of the surrounding groundwater from getting in. And while the practice of freezing soil to create a barrier has been around for more than 150 years, the magnitude of the application that stands before me is quite literally groundbreaking.

“Nobody has taken on a project of this scale,” Hideki Yagi, general manager of Tepco’s Nuclear Power Communications Unit, tells me through an interpreter.

Ice cold

While the term “ice wall” has a colorful ring to it, engineers use the more academic-sounding term Artificial Ground Freezing. The technique came out of France in 1862 as a way to help with the construction of mine shafts before German engineer F.H. Poetsch patented it. Since then, it’s been used to aid in building underwater tunnels or vertical shafts, as well as to cut off groundwater or redirect contaminated materials.

At Fukushima, my eyes follow the path of the pipes, which stretch around the reactor building. A Tepco employee tells me that a calcium chloride solution is pumped down through a smaller inner pipe, and circulated back up a large outer pipe.

The coolant brings down the temperature of each pipe to -30 degrees Celsius, or -22 degrees Fahrenheit, and the pipes are spaced about three feet apart. The cold emanating from each one hardens the soil around it.

The point of the ice wall is to keep the groundwater that runs down from the mountains to the west from entering Fukushima Daiichi and mixing with the toxic water leaking out of the Unit 1, 2 and 3 reactors. That is,  keep the clean water on the outside of the wall, while the contaminated water stays inside.

Tepco and manufacturing partners, such as Toshiba and Mitsubishi, are working on robots to identify and determine how to clear out the radioactive materials in each of the reactors’ primary containment vessels, essentially the heart of each facility.

Until then, they need a way to slow or stop the flow of water into the facility. At least initially, Tepco wasn’t even sure if the project was feasible.

“One of the challenges was how they would inject the pipes into the earth at such a deep level without impacting the other operations around it, and whether it would work,” Yagi says.

With the wall in place, Tepco says it has been able to reduce the level of contaminated water generated from Daiichi. But a Reuters report in March 2018 found that the wall still let a fair amount of clean water in, adding to the volume of toxic water the company needs to deal with. Tepco, however, says it’s been effective in reducing the volume.

“We know this is not the end of our effort,” says a company spokesman. “We will be continuously working hard to reduce the amount of  generation of contaminated water.”

The leaky bucket

Imagine a leaky bucket that constantly needs to be filled with water. At the same time, the water from the leak needs to be collected and stored. And there’s no end in sight to this cycle.

That essentially is the problem that Tepco faces at Daiichi. The fuel rods stored in the three radioactive units constantly have to be cooled with fresh water, but leaks mean the company needs to be vigilant about keeping the tainted liquid from getting out of the facility’s grounds.

Since the accident nearly eight years ago, Tepco has collected 1.1 million tons of contaminated water in 900 tanks stored on the grounds at Daiichi. The company estimates it has enough space in the 37.7-million-square-foot facility to house an additional 270,000 tons of water, which means it would run out sometime in 2020.

“We’re conscious of the fact that we can’t keep storing more and more water,” Kenji Abe, a spokesman for Tepco’s decommissioning and decontamination unit, says through an interpreter.

Tepco has worked on several solutions to decrease the level of contaminated water generated by the facility. The company has switched from tanks sealed with bolts to welded tanks, which offer greater storage capacity and less risk of leaks. There’s a steel wall by the water to keep the contaminants from flowing into the ocean. Tepco has also covered 96 percent of the surface of most of the facility with concrete, preventing rainwater from seeping in.

Then there’s the ice wall, which has done its share of lowering the amount of contaminated water generated from the facility by keeping out most of the groundwater.

Over the past three and a half years, Tepco has seen the amount of polluted water generated fall by a quarter to just under 3,900 cubic feet of water per day, with occasional spikes during periods of rainfall.

The final element

I’m in full protective gear, including a Tyvek coverall, hardhat and full-face respirator mask, walking through one of three water treatment facilities at Daiichi. I move hastily, trying to keep up with my Tepco guides, when my suit gets snagged on an exposed bolt.

Did the suit rip? My eyes shoot back at my photographer and widen with fear. This is usually the part in an outbreak movie that dooms a key character. I look down and see the suit is still intact, and breathe a sigh of relief.

It turns out, I didn’t need to panic. The facility, called the Advanced Liquid Processing System, isn’t radioactive, although it’s designed to remove radioactive elements from the collected water. There are three such facilities, which can process a total of 70,630 cubic feet of water a day.

So far, treatment technology from partner companies like Kurion and Sarry have enabled Tepco to remove 62 of the 63 radioactive elements from the water, but one, tritium, remains.

It’s this one element, which is bonded to the water at an atomic level, that means Tepco needs to keep collecting and storing the water.

Lake Barrett, a senior adviser to Tepco who previously served as acting director of the Office of Civilian Radioactive Waste Management at the US Department of Energy, notes that reactors in China and Canada already discharge water with tritium.

“It’s fundamentally safe,” Barrett says.

But organizations such as Greenpeace have called for Tepco to keep storing the water, noting that much of the early batches of treated water far exceed safety limits for radioactive elements.

Given the sensitivities around Fukushima, Tepco must continue to store the water. A spokesman said the company isn’t planning to disperse the water. But it is one option being considered by the Japanese government, which ultimately makes the decision.

“Resolving the issue of the contaminated water is something we haven’t yet reached a final solution on,” Yagi says.

Analyzing the data

Underneath the building housing the restaurant and employee rest area is a water treatment analysis center, a super-clean area that requires us to go through numerous radiation tests and four sets of boot changes.

There are glass beakers containing sea water, groundwater and water from the ALPS facilities. Scientists walk around in silence, moving beakers from one machine to another. A dozen machines in a second room measure the gamma ray levels.

The facility was originally built underground in 2014 because it needed to be on the Daiichi site, but couldn’t be exposed to radiation because of the nature of the tests. The walls are 8 inches thick, with the more sensitive labs hardened with an additional 20 inches. The facility has grown by 16 times over the past four years as it expanded the number of workers and machines.

“No other facility in Japan can handle the amount of data and work we do here,” says a Tepco scientist working at the facility who preferred not to identify himself.

He adds that all of the data is released publicly. “That’s because society demands work with a high level of trust,” he says.

The scientist explains that Japan has set a legal radioactivity limit of 60,000 becquerel per liter of tritium. But the treated water is still at 1.7 million Bq per liter, or roughly 30 times what’s deemed safe.

So, for now, Tepco must continue collecting the water. And the ice wall continues to stand, invisible to onlookers, as one of the most important lines of defense. ”

by Roger Cheng, CNET

source with photos and a video showing how robots have been used to view melted fuel

Is it safe to dump Fukushima waste into the sea? — The Guardian; Inquisitr

” More than 1,000 tanks brimming with irradiated water stand inland from the Fukushima nuclear plant. Each day 300 tonnes of water are pumped through Fukushima’s ruined reactors to keep them cool. As the water washes through the plant it collects a slew of radioactive particles.

The company that owns the plant – The Tokyo Electric Power Company (Tepco) – has deployed filtration devices that have stripped very dangerous isotopes of strontium and caesium from the flow.

But the water being stored in the tanks still contains tritium, an isotope of hydrogen with two neutrons. Tritium is a major by-product of nuclear reactions and is difficult and expensive to remove from water.

Now, Japan’s Nuclear Regulation Authority (NRA) has launched a campaign to convince a sceptical world that dumping up to 800,000 tonnes of contaminated water into the Pacific Ocean is a safe and responsible thing to do.

NRA chairman Shunichi Tanaka has officially called on Tepco to work towards a release. The International Atomic Energy Agency (IAEA) last year also issued a call for a release to be considered and for Tepco to perform an assessment of the potential impacts. For its part, Tepco has said there are no current plans to release the water. But the Associated Press (AP) reported that company officials are saying in private that they may have no choice.

According to Tanaka, Tritium is “so weak in its radioactivity it won’t penetrate plastic wrapping”. The substance can be harmful if ingested. According to AP, Tanaka had demonstrated the relatively tiny amount of tritium present in the combined Fukushima standing tanks – 57ml in total – by holding a small bottle half full of blue liquid in front of reporters.

A more useful measure of the amount of tritium is its radioactivity, which is measured in becquerels. According to the NRA, the tanks at Fukushima contain 3.4 peta becquerels (PBq) of tritium.

Despite the number of zeros in this measurement (there are 14), this is not a big number, said Ken Buesseler, a senior scientist at the Woods Hole Oceanographic Institution.

To put it in context, the natural global accumulation of tritium is a relatively tiny 2,200 PBq. The isotope has a half life of 12.3 years and is only created naturally on Earth by a rare reaction between cosmic rays and the atmosphere. By far the largest source of tritium in our environment is the nuclear weapons testing program of last century, which dumped a total of 186,000 PBq into the world’s oceans. Over time this has decayed to roughly 8,000 PBq. Another significant source of tritium are nuclear power stations, which have long dumped tritium-contaminated water into the ocean.

“I would think more has been put into the Irish Sea [from the UK’s Sellafield plant] than would ever be released off Japan,” said Buesseler. So far, the Fukushima disaster has seen 0.1-0.5 PBq leaked or released into the Pacific.

Even if all of the contaminated water were released into the ocean, it would not contain enough tritium to be detectable by the time it dispersed and reached the US west coast about four years later, said Simon Boxall, an oceanographer at the University of Southampton.

“In the broad scale of things, if they do end up putting the material in the Pacific, it will have minimal effect on an ocean basin scale,” said Boxall. “In an ideal world, we wouldn’t be in this situation. But the question is, what is the safest way forward? In many ways this is a pragmatic solution.”

But Boxall said there may be local effects – especially on the already heavily impacted fishing industry – as the contaminated water would take time to disperse.

International maritime law prohibits the building of a pipeline to send the waste offshore. Therefore any release would need to be slow. Tepco did not respond to questions regarding the environmental impact study called for by the IAEA.

Despite harbouring few prima facie fears about the 3.4PBq of tritium stored at Fukushima, Buesseler said the lack of transparency surrounding much of the post-tsunami decommissioning process made it impossible to be definitive about the safety of any course of action.

“Until you get the hard data, it’s hard to say if it’s a good idea or not. I want to have independent confirmation of what’s in every tank, which isotopes, how much they want to release per day. You get more of ‘don’t worry, trust us’,” said Buesseler

He notes that there have been minor differences between the official Tepco line that all leaks have stopped and Buesseler’s own measurements of very low levels of caesium and strontium still entering the ocean from the plant.

“It’s easy to have conspiracy theories when no-one is independently assessing what is going on,” he said.

The push for release will also be a blow to the hopes of US start-up Kurion, and their new parent company Veolia, which was awarded a $10m (£7m) grant from the Japanese government in 2014 to demonstrate that its tritium scrubbing technology could be scaled to meet the challenge of the Fukushima problem. The plan would create 90,000 tonnes of hydrogen gas, which Kurion said could be used to power vehicles.

Neither Tepco, nor Kurion, responded to requests for cost estimates of implementing this technology at the site. Kurion’s website calls it “cost-effective” and has said it could have its demonstration plant running within 18 months.

These costs are fundamental to the question of whether to release the material, because whatever they are, it is the price Japan seems unwilling to pay to fully clean up the lingering mess at Fukushima. ”

by Karl Mathiesen


* * *

Here’s another perspective on the dumping of tritiated water in the Pacific by Inquisitr.

How Kurion plans to clean up Fukushima’s tritium nuclear waste — Bloomberg Business

” Innovator: Gaëtan Bonhomme
Age: 39
Chief technology officer at Kurion, a nuclear waste cleanup company with 200 employees that was acquired on Feb. 3 by Veolia, a French waste company

Form and function
Tritium is an especially tough nuclear waste to remove, because it’s a form of hydrogen and naturally bonds with water molecules. Kurion’s hardware separates contaminated water into component elements.

In 2014, Kurion began removing strontium from 400,000 tons of contaminated water at Japan’s Fukushima nuclear power plant.

1. Separation
An electrolyzer splits the water’s oxygen molecules off from its contaminated hydrogen. The oxygen exits through one of the device’s tubes, while the hydrogen and tritium gas flows into a catalytic exchange column, where it’s combined with water.

2. Reduction
Kurion’s proprietary equipment keeps the hydrogen isolated in an ever smaller amount of water cycled through the exchange column. The net effect: 99 percent less contaminated water.

Bonhomme says Kurion took in about $100 million last year selling cleanup equipment and services, like using chemicals and heat to turn toxic waste into glass.

Japan’s economic ministry has granted the company $8.3 million for research.

Next Steps
To show it can handle the tritium at Fukushima, Kurion brought a large-scale demo online at its Richland, Wash., office late last year. Kurion says it could begin processing Fukushima’s tritium-contaminated water in as little as 18 months, but that Japan’s government will likely take until 2018 to evaluate its technology. “We expect to be processing tritium-contaminated water in the U.S. before then,” says Bonhomme. ”


Japanese grant for tritium removal technology — World Nuclear News

” Japan’s Ministry of Economy, Trade and Industry (METI) has awarded US-based waste management specialist Kurion a JPY 1 billion ($10 million) grant to demonstrate technology to remove tritium from contaminated water for possible deployment at Fukushima.

Kurion’s technology is one of three selected by METI in August to go forward to the demonstration phase, alongside offerings from GE Hitachi Nuclear Energy Canada and Russia’s FSUE Radioactive Waste Management Enterprise (RosRAO).

Kurion president John Raymont said the demonstration project would begin immediately at the company’s detritiation facility which is located in Houston, Texas.

Tritiated water is a significant issue at the Fukushima site, where more than 400,000 tons of contaminated water is stored in tanks and a further 400 tons accumulate on a daily basis. Two systems are already in place to remove contaminants from the stored water – a multi-nuclide removal system known as ALPS, and a Kurion’s own mobile processing system known as KMPS. These systems remove contaminants that are suspended or dissolved in the water, but do not remove tritium.

Tritium is an isotope of hydrogen and presents a different problem to other contaminants as it forms tritiated water. A molecule of normal water contains two atoms of hydrogen and one of oxygen, but in a molecule of tritiated water, one of those hydrogens has been replaced with tritium. Industrial processes exist to remove tritium from heavy water. Such processes are used to remove tritium from the heavy water coolant and moderator used in Candu reactors, but are too expensive to be viable for use in removing tritium from the Fukushima waste water or from operating light-water reactors.

The demonstration projects announced by METI earlier in the year must both verify the tritium separation technology and also to assess the construction and operating costs for full-scale implementation of the technology at the Fukushima Daiichi plant. The technology must be capable of removing tritium from water with concentrations of 0.6 and 4.2 million bequerels per litre and to be expandable to process more than 400 cubic metres per day. ”


Assessing Fukushima damage without eyes on the inside — The New York Times

” A particle that barely ranks as a footnote in a physics text may be about to lift the cleanup of the stricken Fukushima Daiichi nuclear complex in Japan over a crucial obstacle.

Inside the complex, there are three wrecked reactor cores, twisted masses of hundreds of tons of highly radioactive uranium, plutonium, cesium and strontium. After the meltdown, which followed a tsunami and earthquake in 2011, most of the material in the plant’s reactors resolidified, in difficult shapes and in confined spaces, wrapped around and through the structural parts of the reactors and the buildings.

Or at least, that is what the engineers think. Nobody really knows, because nobody has yet examined many of the most important parts of the wreckage. Though three and a half years have passed, it is still too dangerous to climb inside for a look, and sending in a camera would risk more leaks. Engineers do not have enough data to even run a computer model that could tell them how much of the reactor cores are intact and how much of them melted, because the measurement systems inside the buildings were out of commission for days after the accident.

And though the buildings may be leaking, they were built of concrete and steel so thick that there is no hope of using X-rays or other conventional imaging technology to scan the wreckage from a safe distance.

To clean up the reactors, special tools must be custom-made, according to Duncan W. McBranch, the chief technology officer at Los Alamos National Laboratory, and the tools “can be much better designed if you had a good idea of what’s inside.” But “nobody knows what happened inside,” he said. “Nobody wants to go in to find out.”

That is where muons come in.

In the next few days, Toshiba, the contractor in charge of the initial cleanup work, and the laboratory expect to sign a formal agreement to deploy a new technology that experts believe will yield three-dimensional images of the wrecked reactor cores, and will be able to differentiate the uranium and plutonium from other materials, even when 10 feet of concrete and steel are in the way.

The Energy Department has been working on the technology for years, and already licenses it in a less advanced form for a more limited job: A Virginia company is using it in a device that screens shipping containers for smuggled uranium or plutonium that could be used in a nuclear bomb. The lab’s new version will be much more ambitious and will focus on mapping rather than just detection.

The technique takes advantage of the fact that everything on earth is constantly being bombarded by muons, subatomic particles that are somewhat like electrons, though about 200 times as heavy. Muons are shaken loose from molecules in the atmosphere by cosmic radiation. Traveling near the speed of light, they rain down on the earth and can penetrate hundreds of feet into it.

But occasionally, one of the muons will happen to hit an atomic nucleus, and when it does, it will change direction in a way that gives a clue about the shape of the target and the target’s density. The technique of detecting those scattered particles and inferring what it was that they bounced off is called muon tomography.

“There is a similarity to X-ray, but the details of the physics are different,” Dr. McBranch said.

Decision Sciences International, a Virginia company, says it can use muon tomography to screen a 40-foot shipping container in 45 seconds and sense whether there is uranium or plutonium in it, though not in great detail. As altered by the Los Alamos scientists for use at Fukushima, the process requires a much longer exposure — it could take weeks. But the result will be a three-dimensional image; concrete, steel and water will all be distinguishable from uranium, plutonium and other very heavy materials.

“You don’t need a quick image, you just need a good image, and you have plenty of time,” said Stanton D. Sloane, the chief executive of Decision Sciences. Testing will begin later this year, officials say, and final images will be produced next year.

“I would expect to be able to distinguish fairly readily between what would be described as random results from the meltdown, versus engineered structural components,” Mr. Sloane said.

The Department of Energy, which runs the Los Alamos lab, does not yet have a formal agreement with Decision Sciences to produce the necessary hardware, but the company is likely to do so.

Mr. Sloane would not say how much the equipment would cost, but the project is small by nuclear standards. Toshiba will reimburse Los Alamos for its costs, which officials said would come to less than half a million dollars. Los Alamos has spent about $4 million developing the technology. Decision Sciences spent additional money to commercialize it, but has not said how much.

The Los Alamos contribution to the Fukushima project is mostly software. The accompanying apparatus, which has already been tried out on a small, intact reactor, consists of two billboard-size detectors, set up on opposite sides of the building. Each detector is like an array of pipes in a church organ, with each pipe filled with inert gases, including argon, that give an indication when a muon hits. The detectors keep track of which pipes were hit on the way in and on the way out, and at what angle. (It is not possible to “tag” a muon, but by timing the detections, the engineers can tell that they spotted the same muon coming and going.)

The detectors do not have to go inside the reactor building. In fact, they would work less well inside, because gamma radiation coming off the melted fuel would make it harder to spot the muons. Instead, the detectors will be set up a few feet away from the reactor buildings’ outer walls, and will be shielded with four inches of steel, which will stop the gamma rays but makes no difference to the muons.

At sea level, about 10,000 muons will pass through each square meter of the detectors every minute. Only a few of them will be deflected and yield useful data, so the detectors will need to run for weeks to gather enough for a clear picture.

Muon tomography is not completely new; it was used in the 1960s to peer inside the Great Pyramid at Giza. But the current version produces images of much higher resolution, according to Dr. McBranch.

Japan is increasingly turning to other countries for the technology needed to clean up Fukushima. This month, Tepco, the utility that operated the power plant, announced a deal with Kurion, a waste-handling company based in Irvine, Calif., for a mobile system to scrub radioactive strontium from 340,000 tons of contaminated water at the site.

Lake H. Barrett, an engineer who is not directly involved in the muon project, said the technique was certainly worth trying. Mr. Barrett was the director of the Nuclear Regulatory Commission office on site at the cleanup of the Three Mile Island nuclear plant near Harrisburg, Pa.; he is now an adviser to the president of Tepco.

Referring to the technology’s use in detecting smuggled weapons fuel, he said, “It’s nice to see the synergy of nonproliferation technologies, on which we in the U.S. have spent hundreds of millions of dollars, applied to another area.”

“How effective it is, we’ll have to wait and see,” he continued. “But we’re all optimistic.” ”


Custom-built robot to probe Fukushima leaks — CNN

” (CNN) — The push to plug the plumbing problem from hell at Fukushima Daiichi is about to get some help from a U.S.-built robot designed to search for leaks from one of the Japanese nuclear plant’s crippled reactors.

Built in Colorado by California-based nuclear cleanup contractor Kurion, the refrigerator-sized robot will stick a 15-foot mechanical arm through a hole in the main floor of the reactor building.

The arm is equipped with radiation-shielded cameras and capable of lifting 100 pounds. It can also carry cutting tools — either a set of heavy-duty shears or a high-pressure water jet that can cut steel.

Kurion custom-built the device to peer into the basement of the Unit 2 reactor building, most of which remains off-limits to humans. The reactor is believed to be leaking highly radioactive coolant water through a rupture in a donut-shaped chamber at the base of the reactor.

Matt Cole, Kurion’s engineering director, said the arm will be used to inspect three areas around that chamber, known as the suppression pool, for suspected leaks. If found, other robots — some still to be developed — will be dispatched to repair the damage, he said.

It doesn’t look like much, but this refrigerator-sized robot may help plug a dangerous leak at the crippled Fukushima nuclear plant in Japan.

“I think it certainly will solve part of that mystery,” Cole said. “They know there is a leak because of the balance of water, but they don’t know exactly where that leak is.”

A nearly 50-foot wall of water slammed into Fukushima Daiichi in the historic earthquake and tsunami that struck eastern Japan in March 2011. The wave flooded the plant and knocked out power to the cooling systems of the three reactors that were running at the time.

The result was the world’s worst nuclear accident since the Chernobyl disaster in 1986, as the reactors overheated and spewed radioactive particles into the environment. Though no deaths have been directly attributed to the Fukushima Daiichi accident, about 138,000 people who were forced to flee homes as far as 25 miles away are still living in temporary housing.

The damage to reactors 1 and 3 was dramatically visible, as massive hydrogen explosions blew apart their concrete housings in the first days of the accident. But what happened in No. 2 has largely remained a mystery.

Four days after the tsunami, operators reported hearing a bang from deep within the reactor, probably from another hydrogen explosion, and a spike in radiation levels. The unit’s turbine plant soon filled with water that was loaded with nuclear wastes, backing up through service tunnels and spilling into the neighboring Pacific Ocean.

This robotic arm is equipped with radiation-shielded cameras and is capable of lifting 100 pounds.

“Some places, the radiation is too high, so people cannot get in,” said Mayumi Yoshida, a spokeswoman for The Tokyo Electric Power Company, which owns the plant. In other parts, workers who go in “have to come out within a few minutes,” she said.
Three years later, operators are still having to pump more than four tons of water an hour — 26,000 gallons every day — into each reactor to keep them cool, Yoshida said. That water builds up in the basements of the reactor buildings, along with hundreds of tons of groundwater that seeps in every day.

TEPCO has had to collect and store thousands of tons of radioactive water in tank farms around the site and is struggling to keep it from leaking back into the environment.

Robots have been able to explore some of the buildings, but have yet to get a good picture of what happened to the suppression pool, Yoshida said. Estimates provided to Kurion indicate that dozens of gallons per hour are escaping from the leak its robot was designed to locate, Cole said.

The device was designed to fit through doors in the damaged building and be installed in a first-floor space where radiation levels are elevated, but still accessible to workers, Cole said. From there, it will reach through the floor and into a basement where hourly radiation exposure would be dozens of times higher than what a typical person receives in a year, according to TEPCO figures.

Engineers can control the robot arm remotely from this command console, allowing them to remain safe from harmful radiation.
“Success for us would be to get clear confirmation of where the leaks are, so that the next phase of the work can be planned,” Cole said.

Engineers eventually want to fill the primary containment vessel surrounding the No. 2 reactor with water, but to do that, they have to fix the leaks, Yoshida said.

The device was shipped to Japan in early May and is expected to be in operation by late summer, Kurion says. The company already has built a system that chills and filters long-lived radioactive cesium out of the reactor coolant — a mechanism it boasts of having put into operation within five weeks. ”