Fukushima’a other big problem: A Million tons of radioactive water — Wired

” The tsunami-driven seawater that engulfed Japan’s Fukushima Daiichi nuclear plant has long since receded. But plant officials are still struggling to cope with another dangerous flood: the enormous amounts of radioactive water the crippled facility generates each day. More than 1 million tons of radiation-laced water is already being kept on-site in an ever-expanding forest of hundreds of hulking steel tanks—and so far, there’s no plan to deal with them.

The earthquake and tsunami that hammered Fukushima on March 11, 2011 triggered meltdowns in three of its six reactors. That left messes of intensely radioactive fuel somewhere loose in the reactor buildings—though no one knows exactly where. What is known, however, is that every day, as much as much as 150 tons of groundwater percolates into the reactors through cracks in their foundations, becoming contaminated with radioactive isotopes in the process.

To keep that water from leaking into the ground or the Pacific, Tepco, the giant utility that owns the plant, pumps it out and runs it through a massive filtering system housed in a building the size of a small aircraft hangar. Inside are arrays of seven-foot tall stainless steel tubes, filled with sand grain-like particles that perform a process called ion exchange. The particles grab on to ions of cesium, strontium, and other dangerous isotopes in the water, making room for them by spitting out sodium. The highly toxic sludge created as a byproduct is stored elsewhere on the site in thousands of sealed canisters.

This technology has improved since the catastrophe. The first filtering systems, installed just weeks after the disaster by California-based Kurion Inc. (which has since been bought by Veolia, a French resource management company), only caught cesium, a strong gamma radiation emitter that makes it the most dangerous of the isotopes in the water. The tubes in those arrays were filled with highly modified grains of naturally occurring volcanic minerals called zeolites. By 2013, the company developed entirely artificial particles—a form of titano silicate—that also grab strontium.

The filters, however, don’t catch tritium, a radioactive isotope of hydrogen. That’s a much trickier task. Cesium and strontium atoms go into solution with the water, like sugar in tea; but tritium can bond with oxygen just like regular hydrogen, rendering the water molecules themselves radioactive. “It’s one thing to separate cesium from water, but how do you separate water from water?” asks John Raymont, Kurion’s founder and now president of Veolia’s nuclear solutions group. The company claims to have developed a system that can do the job, but Tepco has so far balked at the multi-billion dollar cost.

So for now, the tritiated water is pumped into a steadily growing collection of tanks. There are already hundreds of them, and Tepco has to start building a new one every four days.

Tepco has at least reduced the water’s inflow. As much as 400 tons per day was gushing in just a couple of years ago. In an effort to keep the groundwater from getting in, Tepco has built a network of pumps, and in 2016 installed an underground “ice wall”—a $300 million subterranean fence of 30-yard-long rods through which tons of sub-zero brine is pumped, freezing the surrounding earth. All of which helps, but hasn’t solved the problem.

Tritium is far less dangerous than cesium—it emits a weaker, lower-energy form of radiation. Still, all that tritiated water can’t just be stored indefinitely. “Some of those tanks and pipes will eventually fail. It’s inevitable,” says Dale Klein, a former head of the US Nuclear Regulatory Commission who has been consulting with Tepco since the early days following the disaster. (In fact, hundreds of tons of water leaked out of the tanks in 2013 and 2014, sparking an international outcry. Tepco has since improved their design.)

Klein, among others, believes that the concentrations of tritium are low enough that the water can safely be released into the sea. “They should dilute and dispose of it,” he says. “It would be better to have a controlled release than an accidental one.”

But the notion of dumping tons of radioactive water into the ocean is understandably a tough sell. Whatever faith the Japanese public had left in Tepco took a further beating in the first couple of years after the meltdowns, when several investigations forced the company to acknowledge they had underreported the amount of radiation released during and after the disaster. Japan’s fishing industry raises a ruckus whenever the idea of dumping the tritiated water is broached; they already have to contend with import restrictions imposed by neighboring countries worried about eating contaminated fish. Japan’s neighbors including China, Korea, and Taiwan have also objected.

For now, all Tepco can do is keep building tanks, and hope that someone comes up with a solution before they run out of room—or the next earthquake hits. “

by Vince Beiser, Wired

source with internal links and photo

Advertisements

Treated Fukushima water safe for release, Tepco adviser says — Bloomberg

” Treated water from Tokyo Electric Power Co. Holdings Inc.’s wrecked Fukushima nuclear plant north of Tokyo is safe to be released under controlled circumstances into the nearby Pacific Ocean, an independent adviser to the utility said.

“It is much better to do a controlled release in my view than to have an accidental release,” Dale Klein, the adviser and a former chairman of the U.S. Nuclear Regulatory Commission, said in an interview in Tokyo. “I get nervous about just storing all that water when you have about a thousand tanks. You have all the piping, all the valves, everything that can break. ”

More than five years after the meltdowns at Fukushima, Tokyo-based Tepco continues to struggle to contain the radiation-contaminated water that inundates the plant.

About 300 metric tons of water — partly from the nearby hills — flow into Fukushima’s reactor building daily, mixing with melted fuel and becoming tainted, according to the company’s website. For perspective, that’s roughly the amount of water contained in one lane of an Olympic-sized swimming pool.

The water is currently pumped out of the buildings and purified, lowering its radioactive content with a system called Advanced Liquid Processing System, or ALPS. The treated water, which still contains a radioactive element known as tritium, is then stored in one of roughly 1,000 tanks at the site.

Water Challenges

What to do with the treated water remains a headache for Tepco. The utility was urged by the International Atomic Energy Agency in May 2015 to consider discharging the water into the ocean. In early 2014, Klein, the Tepco adviser, criticized the company’s progress in managing the water situation, saying at the time that the task distracted Tepco from other important challenges associated with the cleanup.

Tepco will cooperate with the government, local authorities, and fishermen regarding what to do with the tritium water, spokesman Tatsuhiro Yamagishi said by phone. As of July 28, Tepco stored 668,352 tons of treated water at the Fukushima plant, while 188,462 tons of untreated water was waiting in a second set of tanks to be processed by ALPS, according to Tepco’s Yamagishi.

The government agency overseeing handling of the treated water hasn’t decided whether to go ahead with an ocean release because it needs to “weigh any potential impact on society,” according to an official who asked to not be named, citing internal policy.

“I hope the government will help move towards a decision,” Klein said.

Nuclear power plants routinely and safely release dilute concentrations of tritiated water, according to the the U.S. Nuclear Regulatory Commission.

Release of the “water will not be a safety issue, but it will be an emotional issue,” Klein said. “A lot of people are not going to know what tritium is and they’re just going to perceive that the water is glowing in the dark.” ”

by Stephen Stapczynski

source

Japan’s $25 billion nuclear recycling quest enters 28th year — Bloomberg Business

Fukushima ‘ice wall’ sparks serious concerns — Al Jazeera; The Asahi Shimbun; The Guardian

video source

The Asahi Shimbun: ” An ambitious plan by Tokyo Electric Power Co. to halt the seepage of contaminated water at the stricken Fukushima No. 1 nuclear power plant has hit a major glitch: “ice walls” have failed to form in underground trenches.

TEPCO workers are busy installing underground pipes to circulate coolant to create frozen soil walls encircling the No. 1 through No. 4 reactor buildings on the side away from the sea. Reporters were given a peek at the construction work on July 8.

TEPCO intends next March to start circulating coolants through the pipes to create frozen walls to block underground water from flowing into the reactor buildings.

But on the seaward side of the reactor buildings, the utility must first remove around 11,000 tons of contaminated water from underground trenches connected to the No. 2 and No. 3 reactor turbine buildings.

The trenches, built to house electrical cables and water pipes, are supposed to be kept dry. But contaminated water began seeping into them after the onset of the March 2011 nuclear crisis.

If the contaminated water is not removed from the trenches, it could eventually leak out. The Nuclear Regulation Authority instructed TEPCO to promptly remove the water, calling it the “most serious source of concern.”

To stop the flow of contaminated water into the trenches from reactor turbine buildings, workers have installed cement, clay and coolant pipes to create ice walls around the four connecting points between the reactor turbine buildings and trenches.

After installing the pipes, TEPCO started to freeze them on April 28 to create ice walls in the trenches. It was expected to take about a month to create ice walls, but they had not formed as of July 8.

After the flow of water is halted, the plan calls for the removal of the contaminated water in the trenches.

But TEPCO officials said the ice walls failed to form because of the constant flow of a maximum 2 milliliters of water per minute around the connecting points.

Toyoshi Fuketa, an NRA commissioner, has instructed TEPCO to come up with steps to resolve the matter by the end of July, arguing that the frozen walls should be able to withstand certain levels of water flow under normal circumstances.

The continued presence of water threatens to prevent the creation of outer frozen soil walls encircling the No. 1 through No. 4 reactors, which are a central part of TEPCO’s plans to reduce the amount of contaminated water at the plant.

On June 2, the utility began installing more than 1,500 pipes around the four reactor and turbine buildings to circulate coolant of minus 30 degrees to create ice walls stretching 1,500 meters and running 30 meters deep.

On July 8, workers using heavy machinery were drilling holes to install pipes on the south side of the No. 4 reactor building.

Outfitted in radiation-proof vests, three to four workers manned each drilling machine, making sure not to hit underground obstacles. TEPCO officials said the work can only be carried out between 5 p.m. and 11 p.m. to avoid heatstroke.

The workers are able to install three pipes per day on average. They had installed 90 pipes as of July 7. ”

source

Read a related article, “Doubts over ice wall to keep Fukushima safe from damaged nuclear reactors,” by The Guardian.

Expert: Tepco’s safety culture still insufficient — NHK World; Int’l expert doubts ice wall will solve Japanese nuclear plant leaks — GlobalPost

NHK World:  ” A panel of nuclear experts monitoring reforms at the Tokyo Electric Power Company says the utility’s nuclear safety culture has not yet reached the required level.

TEPCO regularly reports to the independent advisory panel the utility set up after the 2011 accident at its Fukushima Daiichi plant. The utility gives updates on reforms to safety measures at nuclear power plants.

In the latest report, submitted on Thursday, TEPCO officials acknowledge management problems led to troubles with systems used to purify contaminated water, and repeated water leaks.

They say the firm has failed to end the vicious cycle of relying on makeshift systems due to lack of time, which leads to fresh troubles.

They say they were unable to make full preparations for cleanup work while being aware of a lack of technological capabilities.

The chairman of the panel, former US Nuclear Regulatory Commission Chairman Dale Klein, says TEPCO’s safety culture has not reached the desired level in terms of preparing for the unexpected. He says the utility must make sure workers are fully aware that they are dealing with a special plant which caused an accident.

He recommends the utility learn from measures taken at overseas nuclear facilities, and make the most of external support in order to improve operations.

TEPCO executive Takafumi Anegawa says the firm hopes to seek knowhow from abroad to compensate for its lack of on-site operation capabilities. He pledges to swiftly improve operations. ”

source

GlobalPost:  ” An international nuclear expert expressed skepticism Thursday over Tokyo Electric Power Co.’s plan to set up an ice wall to ultimately stop radioactive water from further increasing at the troubled Fukushima Daiichi nuclear complex.

“I’m not convinced that the freeze wall is the best option,” former U.S. Nuclear Regulatory Commission Chairman Dale Klein, who heads a supervisory panel tasked with overseeing the plant operator’s nuclear safety efforts, said in an interview with Kyodo News.

“What I’m concerned about is unintended consequences,” Klein said.

“Where does that water go and what are the consequences of that? I think they need more testing and more analysis,” he said.

Former British Atomic Energy Authority Chairwoman Barbara Judge, who was also present at the interview in Tokyo and is part of the panel, said there is a need to assess during summer whether the ice wall method would be effective.

The remarks by the two overseas experts came at a time when concerns over the plan are being raised by Japan’s Nuclear Regulation Authority and engineering experts. Their opinions may cast a shadow on TEPCO’s plan to begin operating the ice wall by the end of next March.

“No one has built a freeze wall this long for this period of time. Typically, you build a freeze wall for a few months,” Klein said.

Faced with a string of problems including radioactive water leaks at the Fukushima plant, TEPCO is attempting to freeze 1.5 kilometers of soil around the basement areas of the Nos. 1 to 4 reactor buildings.

The ice wall is envisioned to block groundwater from seeping into the reactor buildings’ basement areas and mixing with highly toxic water used to cool the plant’s three crippled reactors.

“I am much in favor of the bypass system,” Klein said, referring to the groundwater bypass system in which TEPCO pumps groundwater at the Fukushima plant to direct it into the sea to reduce the amount of water seeping into the reactor buildings.

“The freeze wall is expensive,” he said, urging TEPCO and the government to look at the cost of building one and whether the plan is making the “best use of limited resources.”

“I would encourage them to get international advice a little bit more,” Klein said about TEPCO, in terms of its decontamination work and future plans to scrap the plant.

Klein also urged the company to work with and share information with relevant authorities in the United States and Britain given that those nations are experienced in water management and decontamination efforts at former military or weapons-related sites.

==Kyodo ”

source