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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Japan pictures likely show melted Fukushima fuel for first time — Bloomberg

” New images show what is likely to be melted nuclear fuel hanging from inside one of Japan’s wrecked Fukushima reactors, a potential milestone in the cleanup of one of the worst atomic disasters in history.

Tokyo Electric Power Co. Holdings Inc., Japan’s biggest utility, released images on Friday showing a hardened black, grey and orange substance that dripped from the bottom of the No. 3 reactor pressure vessel at Fukushima, which is likely to contain melted fuel, according to Takahiro Kimoto, an official at the company. The company sent a Toshiba-designed robot, which can swim and resembles a submarine, to explore the inside of the reactor for the first time on July 19.

“Never before have we taken such clear pictures of what could be melted fuel,” Kimoto said at a press briefing that began at 9 p.m. Friday in Tokyo, noting that it would take time to analyze and confirm whether it is actually fuel. “We believe that the fuel melted and mixed with the metal directly underneath it. And it is highly likely that we have filmed that on Friday.”

If confirmed, the substance — which has the appearance of icicles — would be the first discovery of the fuel that melted during the triple reactor accident at Fukushima six years ago. For Tokyo Electric, which bears most of the clean-up costs, the discovery would help the utility design a way to remove the highly-radioactive material.

The robot, which is about 30 centimeters (12 inches) long, will search for melted fuel at the bottom of the reactor on Saturday. It is possible that the company will take more pictures of what could be melted fuel spread across the floor and lower levels, according to Tokyo Electric’s Kimoto. Fuel from a nuclear meltdown is known as corium, which is a mixture of the atomic fuel rods and other structural materials.

Early Signs

“It is important to know the exact locations and the physical, chemical, radiological forms of the corium to develop the necessary engineering defueling plans for the safe removal of the radioactive materials,” said Lake Barrett, a former official at the U.S. Nuclear Regulatory Commission who was involved with the cleanup at the Three Mile Island nuclear power plant in the U.S. “The recent investigation results are significant early signs of progress on the long road ahead.”

Because of the high radioactivity levels inside the reactor, only specially designed robots can probe the unit. And the unprecedented nature of the Fukushima disaster means that Tepco, as the utility is known, is pinning its efforts on technology not yet invented to get the melted fuel out of the reactors.

Removal Plans

The company aims to decide on the procedure to remove the melted fuel from each unit as soon as this summer. And it will confirm the procedure for the first reactor during the fiscal year ending March 2019, with fuel removal slated to begin in 2021.

Decommissioning the reactors will cost 8 trillion yen ($72 billion), according to an estimate in December from the Ministry of Economy, Trade and Industry. Removing the fuel is one of the most important steps in a cleanup that may take as long as 40 years.

Similar to the latest findings on Friday, Tepco took photographs in January of what appeared to be black residue covering a grate under the Fukushima Dai-Ichi No. 2 reactor, which was speculated to have been melted fuel. However, a follow-up survey by another Toshiba-designed robot in February failed to confirm the location of any melted fuel in the reactor after it got stuck in debris.

A robot designed by Hitachi-GE Nuclear Energy Ltd. also failed to find any melted fuel during its probe of the No. 1 reactor in March.

The significance of Friday’s finding “might be evidence that the robots used by Tepco can now deal with the higher radiation levels, at least for periods of time that allow them to search parts of the reactor that are more likely to contain fuel debris,” M.V. Ramana, professor at the Liu Institute for Global Issues at the University of British Columbia, said by email.

“If some of these fragments can be brought out of the reactor and studied, it would allow nuclear engineers and scientists to better model what happened during the accident.” ”

by Stephen Stapczynski, Bloomberg

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Japanese robot probes the radioactive water at Fukushima’s nuclear reactor to find melted fuel — Daily Mail

” A Japanese robot has begun probing the radioactive water at Fukushima’s nuclear reactor.

The marine robot, nicknamed the ‘little sunfish’, is on a mission to study structural damage and find fuel inside the three reactors of the devastated plant.

Experts said remote-controlled bots are key to finding fuel at the dangerous site, which has likely melted and been submerged by highly radioactive water.

The probe – about the size of a loaf of bread – is equipped with lights, manoeuvres using tail propellers and collects data using two cameras and a dosimeter radiation detector.

Plant operators chose to send the robot inside the containment vessel of the No. 3 reactor because it has highest known water levels out of the the three reactors.

The robot entered the structure at 6.30am JST (10.30 BST, 5.30 ET) through a pipe connected to the containment vessel.

The marine machine, which was attached to cables, then swam to the area just below the reactor pressure vessel inside to take images.

New images taken by the robot show how parts of the system, including the control rod, have been damaged by radiation.

On Friday, the robot will continue its travels to the bottom of the containment vessels, where melted fuel deposits are believed to have accumulated.

In 2011, a 10-metre-high tsunami that killed nearly 19,000 people crashed into Japan’s Fukushima nuclear power plant, leading to several meltdowns.

Five years after the disaster, researchers are still struggling to clean up the highly dangerous radioactive materials in water of the wasting reactors.

It’s estimated that plant officials have only located 10 per cent of the waste fuel left behind after the nuclear meltdowns.

And the damaged plant is believed to be leaking small amounts of the radioactive waste into the Pacific Ocean, which could be travelling as far as the west cost of the US.

Researchers are now pinning their hopes on the remote-controlled sunfish robot to locate the lost fuel in order to work out the safest way to remove it.

During a demonstration of the device at a test facility near Tokyo last month, the probe slowly slid down from a rail and moved across the water.

A team operated it remotely, with one guiding the robot while another adjusted a cable that transmits data and serves as its lifeline.

Japan hopes to locate and start removing fuel from the reactors after Tokyo’s 2020 Olympics.

In earlier operations, snake and scorpion-shaped robots became stuck inside two reactors.

The scorpion robot’s crawling function failed and it was left inside the plant’s Unit 2 containment vessel.

The other, designed for cleaning debris for the ‘scorpion’ probe, was called back after two hours when two of its cameras stopped working after its total radiation exposure reached 1,000 Sievert – a level that would kill a human within seconds.

The plan had been to use the robot for 10 hours at an exposure level of 100 Sievert per hour.

The swimming robot shown was co-developed by electronics and energy giant Toshiba and the government’s International Research Institute for Nuclear Decommissioning. “

by Daisy Dunne, Mail Online and Associated Press

source with photos and video

‘Little sunfish’ robot to swim in to Fukushima reactor — BBC News

” It’ll be a tough journey – previous robots sent in to the ruined nuclear reactor didn’t make it back. … ”

View BBC New’s photo essay on Toshiba’s newest swimming robot, a “little sunfish” that is hoped to withstand off-the-charts radiation levels in Fukushima Daiichi’s wrecked containment vessel.

 

TEPCO must regain public trust to ensure Fukushima’s steady recovery — The Yomiuri Shimbun

” To ensure the steady recovery of Fukushima, Tokyo Electric Power Company Holdings, Inc.’s revised business plan must not be allowed to end up as pie in the sky.

TEPCO has compiled a new business plan. The utility has strengthened its steps to improve profitability to raise funds for costs including decommissioning reactors and compensation related to the March 2011 accident at its Fukushima No. 1 nuclear power plant. This is the second time the plan has been revised.

The total cost of cleaning up the nuclear accident has ballooned from ¥11 trillion to ¥21.5 trillion. TEPCO will shoulder ¥16 trillion of this amount over about 30 years. The ¥300 billion TEPCO spent in fiscal 2016 on compensation and reactor decommissioning costs will be increased to ¥500 billion annually.

TEPCO must boost its “earning power” to secure sufficient capital to meet those costs. Restarting reactors at TEPCO’s Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture will be essential for this. Each reactor brought back online will raise TEPCO’s earnings by ¥40 billion to ¥90 billion per year.

TEPCO is working to gradually restart all seven reactors at the Kashiwazaki-Kariwa plant from fiscal 2019. However, as things stand, high hurdles remain in its way. This is because even if a reactor passes safety screenings conducted by the Nuclear Regulation Authority, local government authorities also must agree to the reactors’ restart.

The recent revelation that TEPCO did not disclose data about the insufficient earthquake-resistance of the main quake-resistant building at the plant has further heightened local distrust of the utility. Niigata Gov. Ryuichi Yoneyama is not budging from his cautious stance because he believes safety measures at the plant are insufficient. “At the moment, I can’t agree to the restart” of the reactors, Yoneyama said.

An expert panel of the Economy, Trade and Industry Ministry also had some stinging criticism for TEPCO, saying it “has not earned enough trust from the public.”

Transparency vital

On June 23, TEPCO will switch to a new leadership lineup when Hitachi, Ltd. Honorary Chairman Takashi Kawamura becomes TEPCO’s chairman. Kawamura will need to work hard to regain trust in TEPCO so restarting its reactors can become a reality.

Strengthening cooperation with other electric utilities and launching new operations, such as gas retailing, also will be effective in solidifying TEPCO’s revenue base. Another issue that needs to be addressed is the overseas development of its thermal power business, in which TEPCO is pursuing integration with Chubu Electric Power Co.

The new plan stipulates TEPCO will “prepare a basic framework for cooperation with other companies” by around fiscal 2020, keeping in mind the Higashidori nuclear plant TEPCO is constructing in Aomori Prefecture.

TEPCO is considering working with Tohoku Electric Power Co., which has a nuclear power plant in that region. If this tie-up comes to fruition, it will be useful for establishing a stable supply of electricity. TEPCO’s intentions on this issue are understandable.

Other utilities that could become partners with TEPCO during a realignment in the industry hold deep-rooted concerns that cooperating with TEPCO could result in the costs of dealing with the nuclear accident being shunted on to them. TEPCO must lay the groundwork to dispel such concerns.

TEPCO and the government will, as soon as this autumn, establish a forum at which they can listen to the opinions of other electric utilities on steps to reorganize nuclear power and electricity transmission businesses.

Profits will be distributed based on the capital contribution ratio in a joint venture. Other companies should not be forced to shoulder the costs of the Fukushima nuclear accident. Highly transparent rules such as these will need to be drawn up. ”

by The Yomiuri Shimbun

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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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