Remote-controlled probe picks up radioactive debris at Fukushima for the first time — Gizmodo

” Tepco, the state-owned operator of the badly damaged Fukushima nuclear plant, has conducted an important test in which a remote-controlled probe managed to grasp several small grains of radioactive debris, AFP reports. The successful operation marked an important achievement for the company as it prepares for a cleanup operation that could take decades.

In March 2011, the devastating Tōhoku earthquake and tsunami triggered the core meltdown of three reactors at the Fukushima Daiichi nuclear power plant. Eight years later, the plant’s operator, Tokyo Electric Power Company Holdings (Tepco), is still in the formative stages of devising a clean-up plan.

The primary challenge, of course, is dealing with the intense radiation emanating from the melted fuel. Two years ago, for example, a robot became unresponsive after just two hours in reactor No. 2; there’s enough radiation down there—approximately 650 sieverts per hour—to fry a person within a few seconds. The episode showed that technical advancements will be required to make robots more resilient to radiation near the core, and that the cleanup will likely take longer than expected.

Early last year, a camera attached to a remote-controlled probe was sent into reactor No. 2. Images confirmed that fuel debris had melted through the reactor pressure vessel (RPV), also known as the reactor core, dripping down into a collection chamber known as the primary containment vessel (PCV). Images of the chamber showed pebble- and clay-like deposits covering the entire bottom of the PCV pedestal. This accumulated waste, along with similar piles at reactors No. 1 and 3, needs to be cleaned up, and Tepco is currently trying to determine the best way of doing so.

To that end, the state-owned company devised an operation to see what that material is like and determine if it can be moved. On Wednesday February 13, Tepco sent a probe equipped with a remotely operated robotic hand down into the No. 2 lower chamber, Japan Times reports. Using its tong-like fingers, the probe picked up five grain-sized pieces of radioactive melted fuel. AFP reported that the pieces were moved to a maximum height of 2 inches (5 centimeters) above the bottom of the chamber. In addition to taking images with a camera, the probe measured radiation and temperature during the investigation, according to a Tepco release.

No radioactive debris was removed from the chamber, but the eight-hour-long operation showed that some of the melted fuel can be moved—an important bit of evidence that will inform future plans to clean up the plant. But as the Japan Times noted, one of the six areas explored by the probe contained debris that had solidified into a clay-like substance, which the robotic hand was unable to grasp. Future robots will need to slice or saw through this material such that it can be removed. That won’t be easy.

A future test, planned for April, will see some debris removed from the chamber, according to the Japan Times. Tepco has yet to disclose how and where this radioactive waste will be stored.

The company is hoping to start removing radioactive fuel in earnest by 2021, but the clean-up is expected to take decades, with some estimates suggesting it won’t be done until the 2050s. Many other technological hurdles still exist, such as determining the full extent of structural damage at the Fukushima plant, locating all the melted fuel in the three damaged reactors, and figuring out a way to remove the large quantities of contaminated water stored at the site.

If that all sounds overwhelming, well, it is. As we’ve said before, when nuclear power goes wrong, it really goes wrong. ”

by George Dvorsky, Gizmodo

source with images and internal links

Here is a related article by Bloomberg.

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Executives In Fukushima nuclear disaster deserve 5-year prison terms, prosecutors say — NPR

” The former chairman and two vice presidents of the Tokyo Electric Power Co. should spend five years in prison over the 2011 flooding and meltdown at the Fukushima Daiichi nuclear plant, Japanese prosecutors say, accusing the executives of failing to prevent a foreseeable catastrophe.

Prosecutors say the TEPCO executives didn’t do enough to protect the nuclear plant, despite being told in 2002 that the Fukushima facility was vulnerable to a tsunami. In March of 2011, it suffered meltdowns at three of its reactors, along with powerful hydrogen explosions.

“It was easy to safeguard the plant against tsunami, but they kept operating the plant heedlessly,” prosecutors said on Wednesday, according to The Asahi Shimbun. “That led to the deaths of many people.”

Former TEPCO Chairman Tsunehisa Katsumata, 78; former Vice President Ichiro Takekuro, 72; and former Vice President Sakae Muto, 68, face charges of professional negligence resulting in death and injury. Muto and Takekuro once led the utility’s nuclear division. All three have pleaded not guilty in Tokyo District Court, saying they could not have predicted the tsunami.

The stricken plant triggered mandatory evacuations for thousands of people. Prosecutors link 44 deaths to the incident, including a number of hospital patients who were forced to leave their facilities.

The sentencing recommendation came as prosecutors made their closing arguments on WedneTsday, more than two years after the executives were initially indicted.

The next step in the case will see a lawyer for victims and their families speak in court on Thursday. But it won’t be until March of 2019 that defense lawyers will deliver their closing arguments, according to Japan’s NHK News.

Hinting at what the defense’s argument might be, NHK cites the prosecutors saying, “the former executives later claimed that they had not been informed, and that the executives put all the blame on their subordinates.”

The case has taken a twisting journey to arrive at this point. In two instances, public prosecutors opted not to seek indictments against the three TEPCO executives. But an independent citizen’s panel disagreed, and in early 2016, prosecutors in the case — all court-appointed lawyers — secured indictments against the three former TEPCO leaders.

Both TEPCO and the Japanese government lost a class-action lawsuit in late 2017, when a court found that officials had not prepared enough for potential disaster at the Fukushima power plant. In that case, the Fukushima district court ordered payments totaling nearly $4.5 million to about 3,800 plaintiffs.

All told, around 19,000 people are estimated to have died in eastern Japan’s triple disaster that included a powerful earthquake off the coast of Tohoku, a devastating tsunami, and the worst nuclear meltdown since the Chernobyl catastrophe of 1986.

In September, Japan’s government announced the first death due to radiation that was released at the Fukushima plant.

The region is still sharply feeling the results of the calamity. As of late November, more than 30,000 people who fled the area had still not returned, Kyodo News reports. ”

by Bill Chappell, NPR

source with internal links

Local Fury and Health Concerns as Japan plans to dump a million tons of radioactive Fukushima water into ocean — Common Dreams

” In a move that has sparked outrage from local residents and dire health warnings from environmentalists, the Japanese government is reportedly planning to release 1.09 million tons of water from the Fukushima Dai-ichi nuclear plant into the Pacific Ocean despite evidence that it contains “radioactive material well above legally permitted levels.”

While both the Japanese government and Tokyo Electric Power Co. (Tepco)—the company that runs the Fukushima Dai-ichi plant—have claimed that radioactive material in the water has been reduced to undetectable amounts and that only “safe levels of tritium” remain, documents obtained by the London-based Telegraph suggest that the cleaning system being used to decontaminate the water “has consistently failed to eliminate a cocktail of other radioactive elements, including iodine, ruthenium, rhodium, antimony, tellurium, cobalt, and strontium.”

“The government is running out of space to store contaminated water that has come into contact with fuel that escaped from three nuclear reactors after the plant was destroyed in the March 2011 earthquake and tsunami that struck northeast Japan,” the Telegraph reported. “Its plan to release the approximately 1.09 million tons of water currently stored in 900 tanks into the Pacific has triggered a fierce backlash from local residents and environmental organizations, as well as groups in South Korea and Taiwan fearful that radioactivity from the second-worst nuclear disaster in history might wash up on their shores.”

One document the Telegraph obtained from the government body charged with responding to the 2011 Fukushima disaster reportedly indicates that the Japanese government is perfectly aware that the Advanced Liquid Processing System (ALPS) is failing to eliminate radioactive materials from the water stored at the Fukushima site, despite its claims to the contrary.

Last September, the Telegraph notes, “Tepco was forced to admit that around 80 percent of the water stored at the Fukushima site still contains radioactive substances above legal levels after the Ministry of Economy, Trade, and Industry held public hearings in Tokyo and Fukushima at which local residents and fishermen protested against the plans.”

Shaun Burnie, a nuclear specialist with Greenpeace, argued that even so-called “safe” levels of tritium are harmful to humans and marine life.

“Its beta particles inside the human body are more harmful than most X-rays and gamma rays,” Burnie told the Telegraph, adding that there “are major uncertainties over the long-term effects posed by radioactive tritium that is absorbed by marine life and, through the food chain, humans.”

The Japanese government’s reported plans to release the water into the Pacific despite these warnings “cannot be considered an action without risk to the marine environment and human health,” Burnie concluded. ”

by Jake Johnson, Common Dreams

source

Seismologist testifies Fukushima nuclear disaster preventable — The Mainichi

” TOKYO — A seismologist has testified during the trial of three former executives of Tokyo Electric Power Co. (TEPCO), operator of the tsunami-ravaged nuclear plant, that the nuclear crisis could have been prevented if proper countermeasures had been taken.

“If proper steps had been taken based on a long-term (tsunami) evaluation, the nuclear accident wouldn’t have occurred,” Kunihiko Shimazaki, professor emeritus at the University of Tokyo, told the Tokyo District Court on May 9.

Shimazaki, who played a leading role in working out the national government’s long-term evaluation, appeared at the 11th hearing of the three former TEPCO executives as a witness.

Prosecutors had initially not indicted the three former TEPCO executives. However, after a prosecution inquest panel consisting of members of the public deemed twice that the three deserve prosecution, court-appointed lawyers serving as prosecutors indicted the three under the Act on Committee for Inquest of Prosecution.

Court-appointed attorneys insist that former TEPCO Vice President Sakae Muto, 67, and others postponed implementing tsunami countermeasures based on the long-term evaluation, leading to the disaster.

The government’s Headquarters for Earthquake Research Promotion released its long-term evaluation in 2002 predicting that a massive tsunami could occur along the Japan Trench including the area off Fukushima.

In 2008, TEPCO estimated that a tsunami up to 15.7 meters high could hit the Fukushima No. 1 power station, but failed to reflect the prediction in its tsunami countermeasures at the power station.

The Cabinet Office’s Central Disaster Prevention Council also did not adopt the long-term evaluation in working out its disaster prevention plan.

Shimazaki, who was a member of the Headquarters for Earthquake Research Promotion’s earthquake research panel in 2002, told the court that the Cabinet Office pressured the panel shortly before the announcement of the long-term evaluation to state that the assessment is unreliable. The headquarters ended up reporting in the long-term evaluation’s introduction that there were problems with the assessment’s reliability and accuracy.

In his testimony, Shimazaki pointed out that the Central Disaster Prevention Council decision not to adopt the long-term evaluation led to inappropriate tsunami countermeasures.

With regard to factors behind the council’s refusal to accept the evaluation, Shimazaki stated that he can only think of consideration shown to those involved in the nuclear power industry and politics.

“If countermeasures had been in place based on the long-term evaluation, many lives would’ve been saved,” Shimazaki told the court.

Shimazaki served as deputy chairman of the government’s Nuclear Regulatory Authority after the Fukushima nuclear disaster.

(Japanese original by Epo Ishiyama, City News Department, and Ei Okada, Science & Environment News Department) “

published in The Mainichi

source

Fukushima residents fight state plan to build roads with radiation-tainted soil — The Japan Times

” The Environment Ministry plans to use radiation-tainted soil to build roads in Fukushima Prefecture, starting with trials in the city of Nihonmatsu next month.

But in the face of fierce protests from safety-minded residents, the ministry is struggling to advance the plan.

“Don’t scatter contaminated soil on roads,” one resident yelled during a Thursday briefing by Environment Ministry officials in Nihonmatsu.

The officials repeatedly tried to soothe them with safety assurances, but to no avail.

“Ensuring safety is different from having the public feeling at ease,” said Bunsaku Takamiya, a 62-year-old farmer who lives near a road targeted for the plan. He claims the project will produce groundless rumors that nearby farm produce is unsafe.

Seven years after the March 2011 core meltdowns at the Fukushima No. 1 nuclear plant, Takamiya has finally been able to ship his produce in Fukushima without worry. Then the ministry’s soil plan surfaced.

A woman in the neighborhood agrees.

“The nature and air here are assets for the residents. I don’t want them to take it away from us,” she said.

Under the plan, tainted soil will be buried under a 200-meter stretch of road in the city. The soil, packed in black plastic bags, has been sitting in temporary storage.

The plan is to take about 500 cu. meters of the soil, bury it under the road at a depth of 50 cm or more, cover it with clean soil to block radiation, and pave over it with asphalt. The ministry intends to take measurements for the project in May.

Fukushima is estimated to have collected about 22 million cu. meters of tainted soil at most. The ministry plans to put it in temporary storage before transporting it to a final disposal site outside the prefecture.

The idea is to reduce the amount. The ministry thus intends to use soil with cesium emitting a maximum of 8,000 becquerels per kg in public works projects nationwide.

The average radiation level for soil used for road construction is estimated at about 1,000 becquerels per kg, the ministry says.

The ministry has already conducted experiments to raise ground levels in Minamisoma with the tainted soil, saying “a certain level” of safety was confirmed.

Similar plans are on the horizon regarding landfill to be used for gardening in the village of Iitate. But it is first time it will be used in a place where evacuations weren’t issued after the March 2011 meltdowns.

Given the protests, an official linked to the ministry said, “It’s difficult to proceed as is.” ”

by Kyodo via The Japan Times

source

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