New proposal suggests removing Fukushima plant’s melted nuclear fuel from side — The Mainichi

” A method to remove melted nuclear fuel debris on the bottom of the containment vessels of Fukushima No. 1 Nuclear Power Plant’s first, second and third reactors from the side was proposed by the Nuclear Damage Compensation and Decommissioning Facilitation Corporation (NDF) on July 31.

Hajimu Yamana, head of the NDF, which is tasked with considering how to remove fuel debris from the reactors, for the first time explained the organization’s specific method proposal to the heads of local governments at a countermeasures for the decommissioning and handling of the contaminated water council meeting held in Iwaki, Fukushima Prefecture.

The method would focus on prioritizing the removal of debris from the bottom of the vessels from the side, using robotic arms and other remote devices while flushing water over the debris. However, ways to block radiation and countermeasures against the scattering of airborne radioactive dust still remain unsolved. The central government and Tokyo Electric Power Co. (TEPCO) plan to finalize their policy to remove the debris and amend the decommission schedule in September.

In all three of the reactors, contaminated water has collected at the bottom of the containment vessels. The NDF had previously considered a “flooding method” that would fill the containment vessels completely with water to block radiation from leaking. However, measures to repair the containment vessels and prevent leakage of the radioactive water would be difficult, so the plan was put aside for having “too many issues.” “

by The Mainichi

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Nuclear authority chief raps Tepco’s attitude toward Fukushima — The Mainichi

” TOKYO (Kyodo) — The head of Japan’s nuclear safety watchdog on Monday criticized the attitude of Tokyo Electric Power Company Holdings Inc. toward decommissioning of the crisis-hit Fukushima Daiichi nuclear power plant and questioned the company’s ability to resume operation of other reactors.

 “I feel a sense of danger,” Nuclear Regulation Authority Chairman Shunichi Tanaka said during a special meeting with the company’s top management, adding that Tokyo Electric does “not seem to have a will to take initiative” toward decommissioning of the crippled Fukushima Daiichi plant.

Takashi Kawamura, the chairman of the power company known as Tepco, and its president, Tomoaki Kobayakawa, attended the meeting. The authority felt it is necessary to hear from the top executives before it could make a decision on whether to approve Tepco’s plan to resume operation of the Nos. 6 and 7 reactors at its Kashiwazaki-Kariwa plant in Niigata Prefecture.

Tepco filed for state safety assessment of the two reactors in September 2013 to reactivate them, hoping to restore its financial condition as it needed massive funds to pay compensation related to the Fukushima Daiichi disaster, triggered by a huge earthquake and tsunami on March 11, 2011, and to scrap the plant that suffered meltdowns.

The watchdog’s safety screening has found Tepco’s failure to report insufficient earthquake resistance of a facility built to serve as the base to deal with a possible nuclear accident at the Niigata complex although it had acknowledged the insufficiency for three years.

In June, Tepco submitted to the watchdog its revised safety measures for the Kashiwazaki-Kariwa complex.

“An operator lacking will to take initiative does not have the right to resume operation of nuclear reactors,” Tanaka said.

Tepco’s chairman responded by saying, “There are citizens who believe nuclear power is necessary. Operating reactors is our responsibility.”

But he also admitted there is room for only two more years’ worth of space in the tanks to accommodate contaminated water stemming from the Fukushima complex.

At Monday’s meeting, the watchdog asked Tepco’s top management about the company’s safety measures for the Niigata complex on the Sea of Japan coast as well as its safety awareness.

Tanaka said the authority does not view that it received sufficient responses from Tepco at the meeting and requested that the company submit more explanation on its plan to decommission the Fukushima complex and resume operation of the two reactors at the Kashiwazaki-Kariwa plant.

Tanaka plans to conduct on-site checkups at the two reactors of the plant in Niigata, saying, “Tepco, which caused the (Fukushima) accident, is not an ordinary operator.”

The two boiling water reactors at the Niigata plant are the same type as those that suffered core meltdowns at the Fukushima Daiichi complex, and no such reactors have cleared the authority’s safety screening since the Fukushima disaster. “

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Nuclear taxes get new lease on life after Fukushima — Nikkei Asian Review

” OSAKA — Japanese prefectures with nuclear power plants are moving to ensure that utilities continue to shoulder a tax burden on reactors even as they are being decommissioned, dramatically raising the cost of cleanup efforts that can last 30 to 40 years.

Five nuclear reactors have been approved for decommissioning since the 2011 meltdowns at Tokyo Electric Power Co. Holdings’ Fukushima Daiichi plant. In each case, the host prefectural government has received approval from the ministry of internal affairs to apply a nuclear tax during decommissioning.

Ehime Prefecture in western Japan, home to Shikoku Electric Power’s Ikata nuclear power plant, has decided to change its ordinances by the fall to enable it to collect taxes on the plant’s No. 1 reactor. Shikoku Electric decided last May to decommission the reactor and has applied to the Nuclear Regulation Authority for approval.

The continued stream of tax revenue will help the Ehime government maintain evacuation routes and other facilities and safety measures until the reactor is fully dismantled and nuclear contamination risks eliminated.

Revenue generator

Of the 13 prefectures that host reactors, only Fukushima does not levy a nuclear fuel tax. Prior to the disaster, most prefectures did not collect these taxes during periods when reactors were shut down for periodic inspections or other reasons. The handful of reactors marked for decommissioning before the disaster have not had their taxes extended.

However, prolonged nuclear power plant shutdowns since Fukushima have prompted local governments to tax reactors based on output capacity even when they are idle to try to wring revenue out of idle units. The moves to extend taxes into decommissioning mark a further step.

Ehime Prefecture’s nuclear fuel tax generated 1.46 billion yen ($13.1 million) in revenues to the government in fiscal 2016, 264 million yen of which came from the inactive No. 1 unit at the Ikata power plant. The government seeks to collect at least half of the full amount during decommissioning.

Fukui Prefecture, home to three reactors approved for decommissioning, expects to collect an annual 370 million yen in revenues from its revised nuclear tax, which comes to half of the standard level.

With the country’s nuclear regulator imposing an in-principle 40-year operating limit on reactors, decommissionings are expected to continue at a pace of one to two units a year. The costs of taking a reactor out of service and rendering the site safe are generally estimated at tens of billions of yen. The tax burden could add up to billions of yen per reactor over the course of decommissioning.

“While the taxes may have benefits for communities, if electric rates go up as utilities’ costs rise, residents will also feel the burden,” said Tatsujiro Suzuki, an authority on nuclear energy policy at Nagasaki University. ”

by Nikkei Asian Review

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Tepco mandated to create fund for scrapping Fukushima plant — The Japan Times

” The Diet passed a bill Wednesday requiring Tokyo Electric Power Company Holdings Inc. to put aside extra funds to decommission its crisis-hit Fukushima nuclear power plant, as the state seeks to gain more financial control over the utility.

Under the revised law, the state-backed Nuclear Damage Compensation and Decommissioning Facilitation Corp. will also be involved in the decommissioning process.

Currently, Tepco has been using profits to pay for scrapping the Fukushima No. 1 plant, which was destroyed after a 2011 earthquake and tsunami triggered a triple meltdown.

The revised law is expected to take effect later this year. With the estimated cost of the decommissioning work already surging to ¥8 trillion from the previously forecast ¥2 trillion, a government panel has called for setting up a funding system that is not dependent on the company’s financial health.

The government projects the total cost to deal with the Fukushima nuclear disaster will reach ¥21.5 trillion, including decommissioning costs, compensation and decontamination work.

Under the new program, the state-backed organization will decide on the amount Tepco should store away each business year and the industry minister must approve it.

The utility must also formulate a financial plan and obtain the minister’s approval when it uses the reserve fund for its decommissioning work.

The new law will strengthen the monitoring power of authorities as well, enabling the industry ministry and the organization to conduct on-site inspections to check whether Tepco is putting aside the money.

The government has a major say in the utility’s operations after acquiring 50.1 percent of the company’s voting rights. Tepco faces huge compensation payments and decommissioning costs among other problems due to the 2011 disaster.

The industry ministry has projected roughly ¥300 billion will be needed annually for the next 30 years to complete the scrapping of the power plant, which involves the difficult procedure of extracting nuclear debris.

The costs could grow further. A study by a Tokyo-based private think tank has shown the bill for the decommissioning could balloon to between ¥11 trillion and ¥32 trillion assuming materials from the No. 1 to 3 reactors, which suffered core meltdowns, need to be specially treated for radioactive waste.

The Japan Center for Economic Research estimated the total cost of managing the disaster could reach ¥70 trillion, more than three times the government calculation. ”

by Kyodo, The Japan Times

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Finding and removing melted fuel rods at Fukushima No. 1 — Nikkei Asian Review, The Japan Times

Nikkei Asian Review, “Survey fails to find melted rods at Fukushima reactors”:

” TOKYO — A remote survey of the Fukushima Daiichi nuclear plant’s No. 1 reactor was unable to locate and photograph melted nuclear fuel, Tokyo Electric Power Co. Holdings said Thursday, complicating efforts to remove that material as part of an extensive cleanup.

Tepco on Saturday sent a robot equipped with a camera into the containment vessel for the No. 1 unit. The majority of fuel rods have melted through the unit’s pressure vessel since the plant was struck by the March 11, 2011, earthquake and tsunami. The prevailing view has been that those melted fuel rods are now sitting under 2.5m of water at the bottom of the containment vessel.

The plan was to explore the bottom section by dipping a camera into the pool of water for the first time. But unexpected barriers such as pipes kept the camera around 1 meter from the bottom in most of the 10 positions surveyed instead of the intended depth of about 40cm from the bottom. While the camera was able to capture sand-like sediment, there was no trace of the melted fuel rods. Adding a fifth day to the investigation turned up no further evidence.

Yuichi Okamura, acting general manager of Tepco’s onsite nuclear power division, offered few comments at the utility’s Thursday news conference, saying only that “photographs and radiation data will need to be evaluated in conjunction with one another.”

The timeline set by Tepco and the government for decommissioning the Fukushima plant aims to begin extraction of melted-down material from the No. 1, No. 2 or No. 3 reactor in 2021 or earlier. An extraction plan is to be decided this summer. But the fact that the status of the melted rods still remains unknown underscores the seriousness of the accident.

The results of the robot survey were “limited,” according to Masanori Naitoh, director of nuclear safety analysis at the Institute of Applied Energy’s Nuclear Power Engineering Center. “It would be difficult to set a plan for extraction based on the information from this survey alone.”

An investigation of the No. 2 reactor also fell short, with the survey robot unable to reach the targeted spot right under the unit’s pressure vessel. ”

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The Japan Times, “Tepco’s biggest hurdle: How to remove melted fuel from crippled Fukushima reactors”:

” Six years after the triple meltdown at the Fukushima No. 1 nuclear power plant, recent investigations underneath the damaged reactor 2 using cameras and robots came close to identifying melted fuel rods for the first time.

Experts say getting a peek inside the containment vessel of reactor 2 was an accomplishment. But it also highlighted how tough it will be to further pinpoint the exact location of the melted fuel, let alone remove it some time in the future.

The biggest hurdle is the extremely lethal levels of radiation inside the containment vessel that not only prevent humans from getting near but have also crippled robots and other mechanical devices.

Safely removing the melted fuel would be a best-case scenario but the risks and costs should be weighed against the option of leaving the melted fuel in the crippled reactors, some experts said.

“The work to probe inside the containment vessels and remove the fuel debris will be extremely tough because of the high radiation levels,” said Hiroshi Miyano, who heads a panel of the Atomic Energy Society of Japan, which is discussing ways to decommission the Fukushima plant and making recommendations to the government.

The government and Tokyo Electric Power Company Holdings Inc. are trying to find a way to remedy the situation but existing methods and technologies may not be sufficient, Miyano said.

In search of melted fuel

The world’s attention turned to the melted fuel rods in late January when Tepco inserted a 10-meter-plus tube equipped with a camera into the containment vessel of reactor 2 to capture images under the pressure vessel that housed the fuel rods.

The images showed black lumps scattered beneath the pressure vessel.

When the March 11, 2011, Great East Japan Earthquake and monstrous tsunami hit, the plant suffered a blackout and lost its key cooling system, triggering meltdowns in reactors 1, 2 and 3. The melted nuclear fuel rods penetrated the pressure vessels and fell into the containment vessels.

Tepco had put cameras inside the containment vessels several times in the past six years but January’s probe was the first to apparently find melted fuel debris.

“We understand that this is a big milestone. We could finally get to see what it was like underneath the pressure vessel,” said Yuichi Okamura, general manager of Tepco’s nuclear power and plant siting division.

“This is critical information in order to remove the fuel debris.”

Radiation barrier

But Tepco hasn’t confirmed that the black lumps are melted fuel, saying they could be paint or cable wrappings, and further investigation is needed.

Capturing the images may be progress but the robot and camera forays have not provided enough information about how to deal with the melted fuel.

Last month, Tepco sent a remote-controlled, scorpion-shaped robot in to further probe inside the reactor 2 containment vessel. But the robot failed before it reached under the pressure vessel after a tire became stuck.

The robot’s dosimeter measured radiation levels of 210 sieverts per hour — enough to kill humans instantly.

While 210 sieverts per hour indicate the melted fuel was nearby, the radiation crippled the robot’s electronics, including its semiconductors and cameras, indicating that the further use of robots to pinpoint the melted fuel will be difficult, robotics experts said.

There are computer chips “designed to withstand a certain level of radiation, but the level inside the containment vessel is totally different,” said Satoshi Tadokoro, a professor at Tohoku University who is an expert on disasters and rescue robots.

The radiation can damage a robot’s chips that serve as their brains, causing the devices to lose control, said Tadokoro, whose robots have also been used at the Fukushima plant.

“On top of the high level of radiation, the entrance (to the containment vessel) for the robot is very small,” restricting what types of robots can be used to hunt for the melted fuel, he said.

Tepco said the opening it created on the side of the reactor 2 containment vessel is about 11 cm in diameter.

Fuel removal strategy

Tepco is set to conduct internal probes of the reactor 1 containment vessel this month and is preparing similar missions for reactor 3.

The government and utility then plan to adopt a basic fuel removal strategy this summer and fine-tune the plan next year, with the actual fuel removal taking place in or after 2021.

There are essentially three options for the strategy, according to the Tokyo-based International Research Institute for Nuclear Decommissioning (IRID), which is developing technologies for the Fukushima plant decommission.

One option is to flood the containment vessels with water and use a crane above the reactors to hoist up the melted fuel. The second option is to carry out the same process but without water. The third is to install removal equipment through the side of the containment vessel.

There are merits and drawbacks to each option, said Shoji Yamamoto, who heads the team developing technologies to create the fuel removal devices at IRID.

The flooding option can block radiation using water, but if the fuel melts into the water, it could pose a risk of recriticality. The debris may need to be cut into pieces for removal, but this process would enable water to get between multiple pieces, creating the condition for recriticality. For nuclear chain reactions to happen there needs to be a certain distance between nuclear fuel and water.

If there is no water, the recriticality risk is minimal but the massive radiation levels cannot be blocked, Yamamoto said.

Tepco’s Okamura said being able to block radiation with water is a huge plus, but noted the reactor 2 containment vessel had cracks and holes that could let injected coolant water escape.

With the Three Mile Island nuclear accident in the U.S., the flooding option was used to retrieve the melted fuel in the 1980s. But the key difference was that all of the melted fuel stayed inside the pressure vessel, so it was easier to flood the reactor.

Because the melted fuel in reactors 1, 2 and 3 at the Fukushima plant all penetrated the pressure vessels and fell into the containment vessels, extracting it from the top or the side was a tough call, Yamamoto said, noting it was important to know the exact location of the melted fuel.

The distance between the top of the pressure vessel and the bottom of the containment vessel is about 45 meters and some parts inside the pressure vessels will need to be removed if Tepco tries to remove the debris inside the containment vessels from the top.

“If we know that the melted fuel is concentrated in the containment vessels, it will be more efficient to remove it from the side” because the entry point is closer, Yamamoto said.

Whatever option is decided, Yamamoto stressed that maintaining the fuel removal device will be difficult because the radiation will probably cripple it.

“The fuel removal device will be controlled remotely … it will be broken somewhere down the line and the parts will have to be replaced, considering its (ability to withstand) radiation,” he said.

“Given that, maintenance will have to be done remotely, too, and that will be a big challenge.”

To remove or not

Another option altogether is for Tepco to leave the melted fuel where it is.

During a media tour of the Fukushima No. 1 plant last month, Okamura of Tepco said the utility intended to collect the melted fuel because leaving it was “not an appropriate way” to manage nuclear fuel.

Miyano of the Atomic Energy Society of Japan said the debris must be removed because radioactive materials, including nuclear fuel, must be strictly controlled under international rules requiring strict monitoring.

Domestic nuclear power plant operators have to report the amount of nuclear fuel they have to the Nuclear Regulation Authority, which then reports to the International Atomic Energy Agency.

“There is the question of whether the government and Tepco decide not to remove the fuel debris. That would be an international issue,” said Miyano, adding that a consensus from the international community would be needed.

At the same time, Miyano said debate and analysis will be required to decide which choice would be best by looking at various factors, including how much it will cost to pick up all the melted fuel and where to store it. ”

by Kazuaki Nagata

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Six years after Fukushima, much of Japan has lost faith in nuclear power — The Conversation

” Six years have passed since the Fukushima nuclear disaster on March 11, 2011, but Japan is still dealing with its impacts. Decommissioning the damaged Fukushima Daiichi nuclear plant poses unprecedented technical challenges. More than 100,000 people were evacuated but only about 13 percent have returned home, although the government has announced that it is safe to return to some evacuation zones.

In late 2016 the government estimated total costs from the nuclear accident at about 22 trillion yen, or about US$188 billion – approximately twice as high as its previous estimate. The government is developing a plan under which consumers and citizens will bear some of those costs through higher electric rates, taxes or both.

The Japanese public has lost faith in nuclear safety regulation, and a majority favors phasing out nuclear power. However, Japan’s current energy policy assumes nuclear power will play a role. To move forward, Japan needs to find a new way of making decisions about its energy future.

Uncertainty over nuclear power

When the earthquake and tsunami struck in 2011, Japan had 54 operating nuclear reactors which produced about one-third of its electricity supply. After the meltdowns at Fukushima, Japanese utilities shut down their 50 intact reactors one by one. In 2012 then-Prime Minister Yoshihiko Noda’s government announced that it would try to phase out all nuclear power by 2040, after existing plants reached the end of their 40-year licensed operating lives.

Now, however, Prime Minister Shinzo Abe, who took office at the end of 2012, says that Japan “cannot do without” nuclear power. Three reactors have started back up under new standards issued by Japan’s Nuclear Regulation Authority, which was created in 2012 to regulate nuclear safety. One was shut down again due to legal challenges by citizens groups. Another 21 restart applications are under review.

In April 2014 the government released its first post-Fukushima strategic energy plan, which called for keeping some nuclear plants as baseload power sources – stations that run consistently around the clock. The plan did not rule out building new nuclear plants. The Ministry of Economy, Trade and Industry (METI), which is responsible for national energy policy, published a long-term plan in 2015 which suggested that nuclear power should produce 20 to 22 percent of Japan’s electricity by 2030.

Meanwhile, thanks mainly to strong energy conservation efforts and increased energy efficiency, total electricity demand has been falling since 2011. There has been no power shortage even without nuclear power plants. The price of electricity rose by more than 20 percent in 2012 and 2013, but then stabilized and even declined slightly as consumers reduced fossil fuel use.

Japan’s Basic Energy Law requires the government to release a strategic energy plan every three years, so debate over the new plan is expected to start sometime this year.

Public mistrust

The most serious challenge that policymakers and the nuclear industry face in Japan is a loss of public trust, which remains low six years after the meltdowns. In a 2015 poll by the pro-nuclear Japan Atomic Energy Relations Organization, 47.9 percent of respondents said that nuclear energy should be abolished gradually and 14.8 percent said that it should be abolished immediately. Only 10.1 percent said that the use of nuclear energy should be maintained, and a mere 1.7 percent said that it should be increased.

Another survey by the newspaper Asahi Shimbun in 2016 was even more negative. Fifty-seven percent of the public opposed restarting existing nuclear power plants even if they satisfied new regulatory standards, and 73 percent supported a phaseout of nuclear power, with 14 percent advocating an immediate shutdown of all nuclear plants.

Who should pay to clean up Fukushima?

METI’s 22 trillion yen estimate for total damages from the Fukushima meltdowns is equivalent to about one-fifth of Japan’s annual general accounting budget. About 40 percent of this sum will cover decommissioning the crippled nuclear reactors. Compensation expenses account for another 40 percent, and the remainder will pay for decontaminating affected areas for residents.

Under a special financing scheme enacted after the Fukushima disaster, Tepco, the utility responsible for the accident, is expected to pay cleanup costs, aided by favorable government-backed financing. However, with cost estimates rising, the government has proposed to have Tepco bear roughly 70 percent of the cost, with other electricity companies contributing about 20 percent and the government – that is, taxpayers – paying about 10 percent.

This decision has generated criticism both from experts and consumers. In a December 2016 poll by the business newspaper Nihon Keizai Shimbun, one-third of respondents (the largest group) said that Tepco should bear all costs and no additional charges should be added to electricity rates. Without greater transparency and accountability, the government will have trouble convincing the public to share in cleanup costs.

Other nuclear burdens: Spent fuel and separated plutonium

Japanese nuclear operators and governments also must find safe and secure ways to manage growing stockpiles of irradiated nuclear fuel and weapon-usable separated plutonium.

At the end of 2016 Japan had 14,000 tons of spent nuclear fuel stored at nuclear power plants, filling about 70 percent of its onsite storage capacity. Government policy calls for reprocessing spent fuel to recover its plutonium and uranium content. But the fuel storage pool at Rokkasho, Japan’s only commercial reprocessing plant, is nearly full, and a planned interim storage facility at Mutsu has not started up yet.

The best option would be to move spent fuel to dry cask storage, which withstood the earthquake and tsunami at the Fukushima Daiichi nuclear plant. Dry cask storage is widely used in many countries, but Japan currently has it at only a few nuclear sites. In my view, increasing this capacity and finding a candidate site for final disposal of spent fuel are urgent priorities.

Japan also has nearly 48 tons of separated plutonium, of which 10.8 tons are stored in Japan and 37.1 tons are in France and the United Kingdom. Just one ton of separated plutonium is enough material to make more than 120 crude nuclear weapons.

Many countries have expressed concerns about Japan’s plans to store plutonium and use it in nuclear fuel. Some, such as China, worry that Japan could use the material to quickly produce nuclear weapons.

Now, when Japan has only two reactors operating and its future nuclear capacity is uncertain, there is less rationale than ever to continue separating plutonium. Maintaining this policy could increase security concerns and regional tensions, and might spur a “plutonium race” in the region.

As a close observer of Japanese nuclear policy decisions from both inside and outside of the government, I know that change in this sector does not happen quickly. But in my view, the Abe government should consider fundamental shifts in nuclear energy policy to recover public trust. Staying on the current path may undermine Japan’s economic and political security. The top priority should be to initiate a national debate and a comprehensive assessment of Japan’s nuclear policy. ”

by The Conversation

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