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Japan revises Fukushima cleanup plan, delays key steps

By MARI YAMAGUCHI
December 27, 2019
TOKYO (AP) — Japan on Friday revised a roadmap for the cleanup of the tsunami-wrecked Fukushima nuclear plant, further delaying the removal of thousands of spent fuel units that remain in cooling pools since the 2011 disaster. It’s a key step in the decadeslong process, complicated by high radiation and other risks. The government and the plant operator, Tokyo Electric Power Co., are keeping a 30- to 40-year completion target.
A look at some of the challenges:
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MORE THAN 4,700 UNITS OF FUEL IN POOLS
More than 4,700 units of fuel rods remain at the three melted reactors and two others that survived the 2011 earthquake and tsunami. They pose a high risk because their storage pools are uncovered and a loss of water in case of another major disaster could cause the fuel rods to melt, releasing massive radiation. Their removal at Units 1 and 2, after repeated delays, is now postponed by up to 10 years from the initial target of 2018, with more preparation needed to reduce radiation and clear debris and other risks.
Fuel rod removal at the Unit 1 reactor pool will begin sometime in 2027-2028, after debris is cleaned up and a huge rooftop cover installed to contain radioactive dust. Fuel removal at Unit 2 pool is to begin in 2024-2026. Work at the Unit 3 reactor pool began in April 2019 and all 566 units will be removed by March 2021. TEPCO has emptied the pool at Unit 4, which was offline and only suffered building damage, and aims to have all remaining rods in reactor pools removed by 2031 for safer storage in dry casks.
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1.2 MILLION TONS OF RADIOACTIVE WATER
TEPCO has been unable to release the 1.2 million tons of treated but still radioactive water kept in nearly 1,000 tanks at the plant, fearing public repercussions and the impact on the area’s struggling fishing and agriculture. The amount of water is growing by 170 tons daily because it is used to cool the melted fuel inside the reactors.
The Ministry of Economy, Trade and Industry recently drafted a proposal to release the water to the sea or the air, or a combination of both. TEPCO says it can only store up to 1.37 million tons, or until the summer of 2022. Time is limited because preparation is needed before any water release. TEPCO and the government say the tanks pose risks if they were to spill their contents in another major earthquake, tsunami or flood. They also need to free up space to build storage for melted fuel removed from reactors beginning 2021.
The water is still somewhat contaminated, but TEPCO says further treatment can remove all but radioactive tritium to levels allowed for release. Experts say tritium is not harmful to humans in small amounts and has been routinely released from nuclear plants around the world.
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880 TONS OF MELTED FUEL
Removing an estimated 880 tons of molten fuel from Fukushima’s three melted reactors is the toughest and unprecedented challenge. It’s six times the amount dealt with in the aftermath of the 1979 Three Mile Island partial core melt in the United States.
Removal is to begin in 2021 at Unit 2, where robotic probes have made more progress than at Units 1 and 3. A robotic arm was developed to enter the reactor from the side to reach the melted fuel, which has largely fallen to the bottom of the primary containment vessel. A side entry would allow the simultaneous removal of fuel rods in the pool from the reactor’s top. The removal of melted fuel will begin with just a spoonful, which will be carefully measured and analyzed under International Atomic Energy Agency instructions. The government hopes to gradually expand the scale of the removal, though further expertise and robotic development is needed. The first decade through 2031 is a crucial phase that will affect future progress. Units 1 and 3 fell behind due to high radiation and water levels respectively, requiring more investigation.
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770,000 TONS OF RADIOACTIVE WASTE
Japan has yet to develop a plan to dispose of the highly radioactive melted fuel and other debris that come out of the reactors. TEPCO will compile a plan for those after the first decade of melted fuel removal. Managing the waste will require new technologies to reduce its volume and toxicity. TEPCO and the government say they plan to build a site to store waste and debris removed from the reactors, but finding one and obtaining public consent will be difficult.
Additionally, there will be an estimated 770,000 tons of solid radioactive waste by 2030, including contaminated debris and soil, sludge from water treatment, scrapped tanks and other waste. They will be sorted, treated and compacted for safe storage under a plan to be compiled by 2028.
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8 TRILLION YEN
The government says Fukushima’s decommissioning cost is estimated at 8 trillion yen ($73 billion), though adding compensation, decontamination of surrounding areas and medium-term storage facilities would bring the total to an estimated 22 trillion yen ($200 billion). The Japan Center for Economic Research, a think tank, estimates that decommissioning alone would cost 51 trillion yen ($470 billion) if the water is not released and tritium removal technology is pursued.
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10,000 WORKERS
More than 10,000 workers will be needed annually in coming years, about one third assigned to work related to the radioactive water. Securing experienced workforce for the decadeslong cleanup is a challenge in a country with rapidly aging and declining population. Nuclear Regulation Authority Chairman Toyoshi Fuketa raised concerns about a possible labor shortage following recent minor mishaps at the plant. TEPCO has expressed intention of hiring workers for the decommissioning under Japan’s new policy allowing more unskilled foreign labor, but the plan is on hold following government instructions to address language and safety concerns.
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This March 11, 2012, file photo, shows three melted reactors, from left, Unit 1, Unit 2 and Unit 3 at Fukushima Dai-ichi nuclear power plant in Okuma, Fukushima prefecture, Japan. Japan revised a roadmap on Friday, Dec. 27, 2019, for the tsunami-wrecked Fukushima nuclear plant cleanup, further delaying the removal of thousands of spent fuel units that remain in cooling pools since the 2011 disaster.
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This Sept. 4, 2017, aerial file photo shows Fukushima Dai-ichi nuclear power plant’s reactors, from bottom at right, Unit 1, Unit 2 and Unit 3, in Okuma, Fukushima prefecture, northeastern Japan. Japan revised a roadmap on Friday, Dec. 27, 2019, for the tsunami-wrecked Fukushima nuclear plant cleanup, further delaying the removal of thousands of spent fuel units that remain in cooling pools since the 2011 disaster. It’s a key step in the decadeslong process, underscoring high radiation and other risks.
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In this Oct. 12, 2017, file photo, ever-growing amount of contaminated, treated but still slightly radioactive, water at the wrecked Fukushima Dai-ichi nuclear plant is stored in about 900 huge tanks, including those seen in this photo taken during a plant tour at Fukushima Daiichi Nuclear Power Plant in Okuma, Fukushima prefecture, northeast of Tokyo. Japan revised a roadmap on Friday, Dec. 27, 2019, for the tsunami-wrecked Fukushima nuclear plant cleanup, further delaying the removal of thousands of spent fuel units that remain in cooling pools since the 2011 disaster. It’s a key step in the decadeslong process, underscoring high radiation and other risks.
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In this Jan. 25, 2018, file photo, a cooling pool where a total of mostly used 566 sets of fuel rods are stored underwater and covered by a protective net, waits to be removed in a step to empty the pool at Unit 3 of the Fukushima Dai-ichi nuclear power plant ahead of a fuel removal from its storage pool in Okuma, Fukushima Prefecture, northeast Japan. Japan revised a roadmap on Friday, Dec. 27, 2019, for the tsunami-wrecked Fukushima nuclear plant cleanup, further delaying the removal of thousands of spent fuel units that remain in cooling pools since the 2011 disaster. More than 4,700 units of fuel rods remain inside the three melted reactors and two others that survived the 2011 earthquake and tsunami.
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In this Nov. 12, 2014, file photo, a Tokyo Electric Power Co. (TEPCO) official wearing a radioactive protective gear stands in front of Advanced Liquid Processing Systems during a press tour at the Fukushima Dai-ichi nuclear power plant in Okuma, Fukushima Prefecture, northeastern Japan. Japan revised a roadmap on Friday, Dec. 27, 2019, for the tsunami-wrecked Fukushima nuclear plant cleanup, further delaying the removal of thousands of spent fuel units that remain in cooling pools since the 2011 disaster.
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Japan has revised a roadmap for the tsunami-wrecked Fukushima nuclear plant cleanup, further delaying the removal of thousands of spent fuel units that remain in cooling pools since the 2011 disaster.

December 30, 2019 Posted by | fukushima 2019 | , , | 6 Comments

Multiple challenges remain to Fukushima nuclear cleanup

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This Sept. 4, 2017 aerial photo shows Fukushima Dai-ichi nuclear power plant reactors, from bottom at right, Unit 1, Unit 2 and Unit 3, in Okuma, Fukushima Prefecture, northeastern Japan. The three reactors that had meltdowns together have 1,573 units of mostly used nuclear fuel rods that are still inside and must be kept cool in pools of water. They are considered among the highest risks in the event of another major earthquake, because the pools are uncovered. The plant operator, Tokyo Electric Power Co. or TEPCO, plans to begin removing the rods from reactor unit 3 in the fiscal year beginning next April 1. However, the latest roadmap delays removal of the rods from units 1 and 2 for three years until fiscal 2023, because further decontamination work and additional safety measures are needed.

Japan’s government approved on Tuesday, Sept. 26, 2017 a revision to the decommissioning plan for the Fukushima nuclear plant, delaying by two more years the removal of radioactive fuel rods in two of the three reactors damaged in the 2011 disaster. It still plans for melted fuel to be removed starting in 2021, but the lack of details about the duration raises doubts if the cleanup can be completed within 40 years. Kyodo News via AP, File)


TOKYO – Japan’s government approved a revised road map Tuesday to clean up the radioactive mess left at the Fukushima nuclear power plant after it was damaged beyond repair by an earthquake and tsunami in 2011. Decommissioning the damaged reactors is an uncertain process that is expected to take 30 to 40 years.

A look at some of the challenges:

THE FUEL RODS

The three reactors that had meltdowns together have 1,573 units of mostly used nuclear fuel rods that are still inside and must be kept cool in pools of water. They are considered among the highest risks in the event of another major earthquake that could trigger fuel rods to melt and release massive radiation due to loss of water from sloshing or structural damage because the pools are uncovered. The plant operator, Tokyo Electric Power Co., or TEPCO, plans to begin moving the rods from reactor Unit 3 in the fiscal year beginning April 1.


However, the latest road map delays removal of the rods from units 1 and 2 for three years until fiscal 2023, because further decontamination work and additional safety measures are needed. Ironically, because the building housing reactor 3 was more heavily damaged, it is easier to remove that unit’s fuel rods. The fuel rods will be moved to a storage pool outside the reactors, and eventually sent for long-term storage in what are known as dry casks.

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THE MELTED FUEL

By far the hardest part of decommissioning Fukushima will be removing the fuel that melted and presumably spilled out of the reactor cores. In July, an underwater robot for the first time captured images inside the primary containment chamber of Unit 3. They showed a large number of solidified lava-like rocks and lumps on the chamber’s floor, believed to be melted fuel mixed with melted and mangled equipment and parts of the structure.

The search for melted fuel in units 1 and 2 has so far been unsuccessful. The water level is lower, so crawling robots have been tried, but they have been obstructed by debris as well as extremely high radiation levels. Despite the unknowns about the melted fuel and debris and their whereabouts, the road map calls for finalizing the removal method in 2019, and starting actual removal at one of the reactors in 2021. The government-funded International Research Institute for Nuclear Decommissioning is developing robots and other technology to carry out the work.

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CONTAMINATED WATER

TEPCO has treated and stored a massive amount of radioactive water — about 800,000 tons — and the volume is growing every day. Cooling water leaks out of the damaged reactors and mixes with groundwater that seeps into the basements of the reactor building, increasing the amount of contaminated water. The utility has managed to halve the volume to 200 tons per day by pumping up groundwater via dozens of wells dug upstream from the reactors, as well as installing a costly “ice wall” by freezing the ground to block some of the water from coming in and going out.

The water is stored in hundreds of tanks that cover much of the plant property. They get in the way of decommissioning work and pose another risk if they were to spill out their contents in another major earthquake or tsunami. After treatment, the water still contains radioactive tritium, which cannot be removed but is not considered harmful in small amounts. Experts say controlled release of the water into the ocean is the only realistic option, but TEPCO has not moved forward with that plan because of opposition from fishermen and residents who fear a negative image and possible health impact.

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RADIOACTIVE WASTE

Japan has yet to develop a plan to dispose of the highly radioactive waste that will come out of the Fukushima reactors. Under the road map, the government and TEPCO will compile a basic plan during fiscal 2018. Managing the waste will require new technologies to compact it and reduce its toxicity. Finding a storage site for the waste seems virtually impossible, as the government has not been able to find a site even for the normal radioactive waste from its nuclear power plants. The prospect raises doubts about whether the cleanup can really be completed within 40 years.

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http://www.miamiherald.com/news/business/article175387901.html

September 26, 2017 Posted by | Fukushima 2017 | , , , | Leave a comment