New minister prioritizes Fukushima decommission
September 14, 2019
Jiji Press FUKUSHIMA (Jiji Press) — The economy, trade and industry ministry will steadily promote decommissioning work at the stricken Fukushima No. 1 nuclear power plant, new minister Isshu Sugawara said Friday.
“Decommissioning work and disposal of tainted water at the plant are the ministry’s highest priorities,” Sugawara said in a meeting with Fukushima Gov. Masao Uchibori.
The nuclear plant, owned by Tokyo Electric Power Company Holdings Inc., is the site of a triple reactor meltdown in March 2011.
Sugawara, who took office on Wednesday as part of Prime Minister Shinzo Abe’s Cabinet reshuffle, said the ministry will also step up support to businesses in areas hit by the nuclear disaster.
Uchibori sought to move nuclear fuel stored at TEPCO’s Fukushima No. 2 nuclear plant, which will also be decommissioned, out of his prefecture.
Speaking to reporters after the meeting, Sugawara said the ministry will work responsively on tackling treated water at the Fukushima No. 1 plant that contains tritium, a radioactive substance.
Japan urges nuke plants to get ready for decommission era
Tokyo Electric Power Co.’s Fukushima No. 2 nuclear power plant
September 2, 2019
Japan’s nuclear policy-setting body adopted a report Monday saying the country is entering an era of massive nuclear plant decommissioning, urging plant operators to plan ahead to lower safety risks and costs requiring decades and billions of dollars.
Twenty-four commercial reactors–or 40 percent of Japan’s total–are designated for or are being decommissioned. Among them are four reactors at the Fukushima No. 1 nuclear power plant that were severely damaged by the massive 2011 earthquake and tsunami that struck northeastern Japan.
The annual nuclear white paper, adopted by the Japan Atomic Energy Commission, urges utilities to learn from U.S. and European examples, especially those of Germany, France and Britain. Japan hasn’t yet completed the decommissioning of any reactors and doesn’t have concrete plans for the final disposal of radioactive waste.
“Taking into consideration further increase of nuclear facilities that will be decommissioned, new technology and systems need to be developed in order to carry out the tasks efficiently and smoothly,” the report said. “It’s a whole new stage that we have to proceed to and tackle.”
Japanese utilities have opted to scrap aged reactors instead of investing in safety requirements under post-Fukushima standards. The decommissioning of a typical reactor costs nearly 60 billion yen ($560 million) and takes several decades.
Before the Fukushima disaster, Japan had 60 commercial reactors that provided about 25 percent of the country’s energy needs.
Despite the government’s renewed ambitions for nuclear power, reactor restarts are proceeding slowly as nuclear regulators spend more time on inspections. Meanwhile, anti-nuclear sentiment persists among the public and makes it more difficult for plant operators to obtain local consent in making revisions to their facilities. Any plan related to nuclear waste storage tends to get strong resistance.
Since the Fukushima accident, only nine reactors in Japan have restarted, accounting for about 3 percent of the country’s energy supply, compared to the government’s ambitious 20-22 percent target.
In July, Tokyo Electric Power Holdings Co., or TEPCO, announced plans to decommission all four reactors at its second Fukushima plant, Fukushima No. 2, which narrowly avoided meltdowns in 2011. The move followed eight years of demands by the local government and residents for the reactors’ closure.
TEPCO said the decommissioning of Fukushima No. 2 alone would cost 410 billion yen and would take four decades, but experts have raised concerns about whether those estimates are realistic for a company already struggling with the ongoing cleanup of the wrecked Fukushima plant, estimated to cost about 8 trillion yen.
Japan Atomic Power Co., which has been decommissioning its Tokai nuclear plant since 2001, announced in March that it was pushing back the planned completion of the project by five years, to 2030, because the company still has been unable to remove and store highly radioactive materials from the core. The decommissioning of the government’s Tokai fuel reprocessing facility is expected to take 70 years and cost 770 billion yen.
The white paper stated that Japan is pursuing its divisive spent-fuel reprocessing ambitions and a plan to develop a fast-breeder reactor despite international concerns over the country’s plutonium stockpile of 47 tons, though the commission calls for more efforts in reducing the stockpile and increasing transparency.
France’s recently reported move to abandon ASTRID, its next-generation fast reactor that would theoretically produce more plutonium while burning it as fuel, could be a setback for Japan, which was hoping to jointly develop the technology.
TEPCO submits decommissioning plan for Onagawa 1
Another Japanese boiling water reactor calls its quits and moves to decommission. This the fifth Japanese boiling water reactor in a week pulled from even having hope of restart along with Fukushima Daini 1 through 4. Who says “operating experience” isn’t shrinking for boiling water reactors in USA and around the world?
02 August 2019
Tohoku Electric Power Company has applied to Japan’s Nuclear Regulation Authority (NRA) for approval of its decommissioning plan for unit 1 of the Onagawa nuclear power plant in Miyagi Prefecture. The company announced in October 2018 its decision to scrap the unit as it said required safety upgrades would be too expensive and time-consuming.
Unit 1 of the 524 MWe boiling water reactor (BWR) that began operations in 1984 is of a different design to the other two larger (825 MWe) BWR units there, which began operating in 1995 and 2002, respectively. Tohoku also operates a single 1100 MWe BWR at its Higashidori plant in Aomori Prefecture, which started operation in late 2005. Tohoku plans to restart units 2 and 3 at the Onagawa plant, as well as its Higashidori plant.
Last October, Tohoku said a problem unique to Onagawa 1 is the restricted space within its containment vessel in which to install additional safety equipment, such as fire extinguishing equipment, power supply equipment and alternative water injection pumps. It decided to decommission the unit after taking into account its generating capacity and the number of years it would be able to operate if it were restarted. Onagawa 1 became the tenth operable Japanese reactor to be declared for decommissioning since the March 2011 Fukushima Daiichi accident.
Its decommissioning plan for the unit, which it submitted to the NRA on 29 July, outlines the facilities and equipment to be dismantled and a timetable for completing the work. Decommissioning will take about 34 years and will be carried out in four stages. The first stage, lasting about eight years, will involve preparing the reactor for dismantling (including the removal of all fuel and surveying radioactive contamination), while the second, lasting seven years, will be to dismantle peripheral equipment from the reactor and other major equipment. The third stage, taking about nine years, will involve the demolition of the reactor itself, while the fourth stage, taking about ten years, will see the demolition of all remaining buildings and the release of land for other uses.
During the first stage, all fuel is to be removed from the operation of Onagawa 1. This includes 821 used fuel assemblies stored in unit 1’s storage pool, which will be transferred to unit 3’s storage pool. These assemblies will later be transported for reprocessing, together with 95 used fuel assemblies from unit 1 currently stored at unit 2 and 66 stored at unit 3. There are also 41 unused fuel assemblies stored at unit 1.
A total 60 tonnes of high-level radioactive waste is expected to be generated through the decommissioning of Onagawa 1, together with 740 tonnes of low-level waste and 5340 tonnes of very low-level waste. A further 12,400 tonnes of non-radioactive waste will also be generated through the clearance of the site.
Tohoku said it expects the decommissioning of the unit to cost a total of JPY41.9 billion (USD392 million), with dismantling activities costing JPY30.0 billion and waste disposal accounting for the remainder.
In March 2015, the Ministry of Economy, Trade and Industry’s Agency for Natural Resources and Energy revised the accounting provisions in the Electricity Business Act, whereby electric power companies can now calculate decommissioning costs in instalments of up to 10 years, instead of one-time as previously. This enhanced cost recovery provision was to encourage the decommissioning of older and smaller units.
The Onagawa plant is on Japan’s northeastern coast and was the closest plant to the epicentre of the earthquake and tsunami of 11 March 2011. Although the earthquake knocked out four of the five external power lines, the remaining line provided sufficient power for the plant’s three reactors to be brought to cold shutdown. Onagawa 1 briefly suffered a fire in the non-nuclear turbine building. A mission from the International Atomic Energy Agency in August 2012 concluded the plant had been largely unaffected by the tsunami as it sits on an elevated embankment more than 14 metres above sea level.
Decision to Scrap Fukushima Daini 4 Reactors
TEPCO officially decides to abolish Fukushima Daini nuclear plant
This photo taken from a Kyodo News helicopter on June 14, 2018, shows the Fukushima Daini nuclear power plant in Fukushima Prefecture, northeastern Japan.
July 31, 2019
TOKYO (Kyodo) — Tokyo Electric Power Company Holdings Inc. officially decided Wednesday at a board meeting to abolish the Fukushima Daini nuclear complex near the Daiichi plant crippled by the March 2011 disaster.
It means that all 10 nuclear reactors in the northeastern prefecture, including the six at the Fukushima Daiichi complex, will be scrapped, though this will take decades. TEPCO President Tomoaki Kobayakawa met Fukushima Gov. Masao Uchibori and reported the decision.
The decommissioning work of the four nuclear reactors at the Daini plant will likely cost some 280 billion yen ($2.6 billion) and require more than 40 years. The power company plans to build an on-site facility to store spent nuclear fuel from the plant, though it has yet to pick a final disposal site for the fuel.
The Daini complex started the four reactors’ commercial operation from 1982 to 1987. The nuclear power plant was also hit by the tsunami in the 2011 disaster, temporarily losing key cooling functions, but managed to avoid meltdowns that occurred at the Daiichi plant.
The prefecture has called for scrapping the Daini plant, saying its existence has been hampering reconstruction efforts.
Fukushima gov. accepts TEPCO decision to scrap Daini nuclear plant
This photo taken on June 14, 2018, shows the Fukushima Daini nuclear power plant in the northeastern Japan prefecture of Fukushima
July 31, 2019
FUKUSHIMA, Japan (Kyodo) — Fukushima Gov. Masao Uchibori said Tuesday his prefecture will accept Tokyo Electric Power Company Holdings Inc.’s recent decision to scrap the Fukushima Daini nuclear complex near the Daiichi plant crippled by the March 2011 disaster.
In a meeting with Tomoaki Kobayakawa, the president of the utility known as TEPCO, the governor also accepted its plan to build an on-site storage facility to store spent nuclear fuel.
The decision means all 10 nuclear reactors in the northeastern prefecture, including the six at the Fukushima Daiichi complex 12 kilometers from the Daini plant, will be scrapped, though the decommissioning work will take decades.
The March 2011 earthquake and tsunami did not cause serious structural damage to the Daini plant, while three of the reactors at the Daiichi complex experienced meltdowns.
TEPCO’s decision to scrap the Daini complex, expected to cost around 280 billion yen ($2.6 billion), will be formally approved at the company’s board meeting on Wednesday.
“I’m grateful that I received a certain degree of understanding. We will proceed (with the decommissioning) with a renewed sense of responsibility,” Kobayakawa said in the meeting with the governor.
Uchibori and Kobayakawa discussed TEPCO’s plan last week, with the governor saying that while he welcomed the scrapping of the reactors he needed to consult the towns hosting the complex about the storage facility.
TEPCO has not picked a final disposal site for the spent fuel from the Daini complex, raising concern among local residents that the radioactive nuclear waste may remain stored on-site for a long time.
“The premise is that the nuclear fuel will be transported out of the prefecture. Temporary storage for the time being is unavoidable,” Uchibori said.
He later told reporters TEPCO had assured him that the storage facility would not be permanent.
The Daini plant currently has around 10,000 assemblies of spent fuel cooling in pools.
The scrapping of the Daini plant also means that the central government’s annual subsidies of around 1 billion yen ($9.2 million) each for the towns of Naraha and Tomioka that host the facility will eventually be terminated.
Revenue linked to the nuclear plant, from property taxes and in other forms, accounted for 25 percent of Naraha’s total revenue and 40 percent of Tomioka’s.
Uchibori said he will ask the government to take into account “the financial situation of the two towns in view of the special circumstances relating to the decommissioning.”
TEPCO bears responsibility for decommissioning over generations
Tokyo Electric Power Co.’s Fukushima No. 2 nuclear power plant
July 29, 2019
Tokyo Electric Power Co. has announced that it will decommission all four reactors at its Fukushima No. 2 nuclear power plant.
The decision indicates the landscape of nuclear energy in Japan is entering an age of mass decommissioning.
TEPCO plans to work concurrently to scrap a total of 10 nuclear reactors, including all six at the Fukushima No. 1 nuclear power plant, the site of the 2011 disaster. The task will be almost unparalleled and unprecedented in the world in terms of its scale.
TEPCO should fulfill its momentous duties in undertaking the task to help rebuild disaster-stricken communities of Fukushima Prefecture.
It took TEPCO an entire year to make the latest decision after the utility said last year it would consider the decommissioning option. That is enough evidence there are high barriers to be surmounted.
One difficulty consists in ensuring the availability of workers.
A staff of 3,600 is currently working to scrap the Fukushima No. 1 nuclear plant, where four reactors went crippled. Work to grasp the full picture of the reactor interiors, where nuclear fuel melted down, remains in a trial-and-error stage and is facing extremely rough going.
The latest decision means the Fukushima No. 2 plant, a logistic support base for those efforts, will itself be an additional site of decommissioning work.
TEPCO officials said they have largely figured out how the work will be done. We are left to wonder, however, how they plan to get all the necessary, highly skilled workers.
The task should be undertaken cautiously and steadily so there will be no accidents.
While it is believed it takes about 30 years to decommission a typical nuclear reactor, TEPCO officials said it will likely take more than 40 years to scrap all the reactors at the Fukushima No. 2 plant because the work cannot be done on all four reactors there in one continuous period.
That is about the same span of time that someone spends working for a company from entrance as a new hire through retirement age. The efforts will straddle generations.
TEPCO will be required to keep its staff highly motivated and to overcome any difficulties responsibly during all that time.
While the scrapping work will only start after specific plans for it have been approved by the government’s Nuclear Regulation Authority, solutions have yet to be decided for many anticipated problems.
The four reactors of the Fukushima No. 2 plant contain about 10,000 spent nuclear fuel assemblies. TEPCO plans to have them stored temporarily on the grounds of the nuclear plant before having them taken out of Fukushima Prefecture.
But where exactly they will be taken “will be studied in the years to come,” said Tomoaki Kobayakawa, president of TEPCO Holdings Inc.
Some rules remain to be determined for the disposal of radioactive waste, of which more than 50,000 tons are expected to be produced.
Decommissioning of nuclear reactors is a challenge that faces all major electric utilities.
Decisions have been made to scrap 21 nuclear reactors in the wake of the Fukushima disaster, and more are expected over time.
The question of what to do with spent fuel and radioactive waste should not be put on the back burner. The government should work to solve it.
Rising costs due to tightened safety measures have given a push to utilities’ decisions to scrap their reactors. Only nine reactors have so far been brought back online following the Fukushima disaster.
Plans to build new nuclear plants and reactors are making little progress. As a matter of reality, nuclear energy is losing the status of a mainstay power source.
That notwithstanding, utilities still stick to their old stance of continued reliance on nuclear power, saying they want to utilize what they have.
TEPCO is no exception. The owner of seven reactors at the Kashiwazaki-Kariwa nuclear plant in Niigata Prefecture is hoping to reactivate the No. 6 and No. 7 reactors there for starters.
Major utilities, especially TEPCO, are required to face up to the tough reality and look at what lies beyond the age of mass decommissioning. They bear the social responsibility to assign ample human and financial resources for renewable energy sources, which will be a major pillar of power supply for the next generation, among other areas.
TEPCO to decommission all four reactors at Fukushima Daini
The No. 4 reactor building stands at Tokyo Electric Power Co. Holding’s Fukushima No. 2 nuclear power station in Naraha, Fukushima Prefecture, in July 2012
Tepco to decommission reactors at Fukushima No. 2 nuclear plant
July 20, 2019
Tokyo Electric Power Co. Holdings Inc. will formally decide to decommission the Fukushima No. 2 nuclear plant after informing the prefecture’s governor of its policy as early as this month, a company source has said.
Excluding the nearby No. 1 plant, which was crippled by the March 2011 earthquake and tsunami disaster, it is the first time that the utility has decided to decommission a nuclear facility, the source said Friday.
The decommissioning of all four reactors at the No. 2 plant will likely require more than 40 years and cost an estimated ¥280 billion ($2.6 billion), the source added. If realized, all 10 reactors in Fukushima Prefecture will be scrapped.
Tepco now believes that it can secure funds to cover costs for the decommissioning and necessary workers, sources said.
The company will submit a specific decommissioning plan to the Nuclear Regulation Authority by the end of March 2020, according to the sources.
Closure of the No. 1 plant, which suffered core meltdowns at three of its six reactors, has already been decided.
After telling Fukushima Gov. Masao Uchibori about the policy, it could be formally approved at a Tepco board meeting scheduled for the end of this month, the source said.
The No. 2 complex was also hit by tsunami waves in the 2011 disaster and temporarily lost reactor cooling functions. But unlike the No. 1 plant, it escaped meltdowns.
Since the disaster, firms operating 21 nuclear reactors in the nation, including those at the No. 2 plant, have decided to decommission the facilities.
If the decision is approved by the board, the Tokyo-based utility’s Kashiwazaki-Kariwa plant in Niigata Prefecture will become its only nuclear complex.
In June last year, Tepco President Tomoaki Kobayakawa told the governor that the company is leaning toward scrapping all four reactors at the No. 2 plant. A project team was later formed at the utility and looked into whether that is possible, according to the source.
The prefecture has demanded the utility scrap the reactors, saying their existence would hamper its reconstruction efforts.
Tepco to retire remaining reactors in Fukushima
Decommissioning is expected to take 40 years and cost $2.5bn
Tepco plans to authorize the decommissioning of all four Fukushima Daini reactors this month, a project estimated to cost $2.5 billion.
July 20, 2019
TOKYO — Tokyo Electric Power Co. Holdings will scrap the four Fukushima Prefecture reactors that escaped damage in the 2011 earthquake and tsunami, moving to decommission all of the nuclear power plants the public utility owns in the disaster-stricken region.
The shutdown of the Fukushima Daini plant, which is located just 12km away from the Daiichi Plant crippled by fuel meltdowns, will be formally authorized at the company’s board meeting at the end of the month. This marks the first decision by the utility, known as Tepco, to decommission nuclear reactors apart from the Daiichi facilities.
Costs for decommissioning Fukushima Daini are estimated to exceed 270 billion yen ($2.5 billion). While Tepco’s reserves are not enough to cover them, the government adopted new accounting rules allowing operators to spread a large loss from decommissioning over multiple years. The company also believes it has secured enough people with necessary expertise to move forward.
Tepco soon will inform Fukushima Gov. Masao Uchibori of its decision. The utility intends to submit the decommissioning plan to Japan’s Nuclear Regulation Authority by March next year.
The decision means all 10 reactors in Fukushima will be scrapped. The Daini reactors will be decommissioned in roughly 40 years, sharing the same timetable as the Daiichi site. Tepco owns one other nuclear plant, the Kashiwazaki-Kariwa facility in Niigata Prefecture.
The Daini plant, where each reactor produced 1.1 gigawatts of power, served the Tokyo area for about three decades. Japan’s central government sought to restart the complex but faced withering opposition from local residents in Fukushima.
Including the Fukushima Daini facilities, a total of 21 reactors across Japan are now slated for decommissioning. Recent additions include two units at the Ikata plant in Ehime Prefecture and one reactor at the Onagawa facility in Miyagi Prefecture.
TEPCO to decommission Fukushima Daini nuclear plant
July 19, 2019
Tokyo Electric Power Company Holdings Inc. will formally decide to decommission the Fukushima Daini nuclear plant after informing the prefecture’s governor of its policy as early as this month, a company source said Friday.
Excluding the nearby Daiichi, crippled by the March 2011 earthquake and tsunami disaster, it is the first time that the utility, also known as TEPCO, has decided to decommission a nuclear plant.
The decommissioning of all four nuclear reactors at Daini will likely require more than 40 years and some 280 billion yen ($2.6 billion) in costs, the source said. If realized, all 10 nuclear reactors in Fukushima Prefecture will be scrapped.
Closure of the Daiichi plant, which suffered core meltdowns at three of its six reactors, has already been decided.
After telling Fukushima Gov. Masao Uchibori about the policy, it may be formally approved at a TEPCO board meeting, scheduled at the end of this month, the source said.
The Daini complex was also hit by tsunami waves in the 2011 disaster and temporarily lost reactor cooling functions. But unlike the Daiichi plant, it escaped meltdowns.
Since the disaster, the decommissioning in Japan of 21 nuclear reactors, including those at Daini, has been decided.
For the Tokyo-headquartered power company, the Kashiwazaki-Kariwa plant in Niigata Prefecture will be its only nuclear complex.
In June last year, TEPCO President Tomoaki Kobayakawa told the governor that the company is leaning toward scrapping all four reactors at the Daini plant. A project team was later formed at the utility and looked into whether that is possible, according to the source.
The prefecture has demanded the utility scrap the reactors, saying their existence would hamper its reconstruction efforts.
AECOM signs agreement with Toshiba to perform nuclear decommissioning services in Japan
The signing of the collaboration agreement. From left to right: Dan Brouillette, Deputy Secretary, U.S. Department of Energy; Mark Whitney, Executive Vice President and General Manager for AECOM’s Nuclear & Environment strategic business unit; Goro Yanase, Chief Nuclear Officer, Toshiba ESS; and Taizo Takahashi, Commissioner, Agency for Natural Resources and Energy (ANRE).
June 17, 2019
LOS ANGELES–(BUSINESS WIRE)–
The partnership will expand access to the key Asian market that is valued at $50 billion and further underscores AECOM’s leading nuclear decontamination and decommissioning capabilities
AECOM (ACM), a premier, fully integrated global infrastructure firm, and Toshiba have signed an Alliance Agreement to work together on decommissioning nuclear reactors in Japan. This is a major step forward that combines AECOM’s 30 years of experience in nuclear decommissioning with Toshiba’s long history of supporting the nuclear industry. The alliance will offer comprehensive services to Japanese government organizations and commercial power utilities that plan to decommission their reactors and nuclear facilities.
This press release features multimedia. View the full release here: https://www.businesswire.com/news/home/20190617005844/en/
“We are proud to be in an Alliance with such a respected company and excited about marketing our collective capabilities to the Japanese government and utilities,” said Michael S. Burke, AECOM’s chairman and chief executive officer. “We believe this Alliance has the right experience, capabilities, skill mix and resources to meet the needs of this nuclear cleanup market. We have had tremendous success in nuclear decommissioning for the U.S. Department of Energy and the UK’s Nuclear Decommissioning Authority, as well as commercial clients around the world, and we look forward to supporting the Japanese utilities through this Alliance.”
AECOM is the market leader in the U.S. and U.K. for managing high-hazard, complex nuclear decommissioning programs. This includes work for the U.S. Department of Energy at key sites, such as Hanford, Savannah River, Oak Ridge and the Waste Isolation Pilot Plant. AECOM also is a leader in the U.K. decommissioning market with major contracts at the Nuclear Decommissioning Authority facilities at Dounreay and the Low Level Waste Repository. Including the Company’s work for commercial nuclear utilities, such as at the San Onofre Nuclear Generating Station in Southern California, AECOM is viewed as a world leader in this expanding clean-up market. Combining AECOM‘s expertise with the local knowledge and capabilities of Toshiba, the Company can expand the full range of required decommissioning services to Japan.
“We are excited to partner with Toshiba and further expand our expertise in the nuclear D&D market,” said John Vollmer, AECOM’s president of its Management Services group. “In addition to our ongoing work at key U.S. Department of Energy sites and our recent selection for the $400 million Dounreay decommissioning framework, our teams have demonstrated a high level of success as we continue to expand our share within this high-growth market.”
Within the nuclear decommissioning sector, AECOM provides program management; planning, design and engineering; systems engineering and technical assistance; construction and construction management; operations and maintenance; environmental remediation; waste management and decommissioning, dismantling and closure services to a broad range of clients.
About AECOM
AECOM (ACM) is built to deliver a better world. We design, build, finance and operate critical infrastructure assets for governments, businesses and organizations. As a fully integrated firm, we connect knowledge and experience across our global network of experts to help clients solve their most complex challenges. From high-performance buildings and infrastructure, to resilient communities and environments, to stable and secure nations, our work is transformative, differentiated and vital. A Fortune 500 firm, AECOM had revenue of approximately $20.2 billion during fiscal year 2018. See how we deliver what others can only imagine at aecom.com and @AECOM.
Unit 2 of Genkai NPP will be decommissioned.
Unit 3 and 4 of Genkai are still operating.
Kyushu Electric Power Co. said Wednesday it will scrap No. 2 reactor at its Genkai nuclear power plant in Saga Prefecture, seen in the forefront left of this photo taken in January
Feb 13, 2019
FUKUOKA – Kyushu Electric Power Co. said Wednesday it has decided to scrap its aging No. 2 reactor at its Genkai nuclear plant in Saga Prefecture.
The utility abandoned a plan to restart the unit, which has an output of 559 megawatts, in the face of the huge costs involved in enhancing the safety of the reactor that is already near the end of its 40-year operating life.
The reactor, which started operating in March 1981, has been idled since a routine checkup shortly before the March 2011 earthquake and tsunami disaster that triggered the Fukushima nuclear crisis.
The Genkai plant consists of four units. The utility already decided in 2015 to scrap its aging No. 1 unit, which had the same output capacity as the No. 2 reactor. Decommissioning work at the No. 1 reactor started in July 2017 and is expected to continue through fiscal 2043.
There have been a number of operational problems at the Genkai power plant. In May last year, pumps installed to control the circulation of cooling water at the No. 4 unit suffered malfunctions, following a steam leak from a pipe at the No. 3 reactor just a week after it was reactivated in March.
Some local residents have sought to stop operation of the Nos. 3 and 4 units with a temporary injunction, with doubts about the safety measures taken and citing the risk of volcanic eruptions in the region. Their case is pending at the Fukuoka High Court.
50% in nuclear industry: Energy plan for 2030 is ‘unrealistic’
Tohoku Electric Power Co. has decided to decommission the No. 1 reactor at the Onagawa nuclear power plant in Miyagi Prefecture.
December 5, 2018
Half of companies in the nuclear industry doubt the government’s goal of having nuclear power account for 20 to 22 percent of Japan’s energy supply by fiscal 2030, according to a survey.
The reasons for their skepticism relate mainly to difficulties restarting or building reactors under stricter safety measures taken after the Fukushima nuclear disaster in 2011.
The survey was conducted in June and July by the Japan Atomic Industrial Forum, whose members include electric power companies that operate nuclear plants.
The forum contacted 365 companies in the nuclear industry, such as equipment manufacturers, and received responses from 254, or 70 percent.
According to the results, 50 percent of the companies said the government’s nuclear energy goal for fiscal 2030 is “unachievable,” compared with only 10 percent that said it is “achievable.” Forty percent said the attainability is “unknown.”
An estimated 30 reactors must be operating to reach the target, but the resumption of reactor operations has been slow since all of them were shut down after the triple meltdown at the Fukushima No. 1 nuclear power plant.
“Only nine reactors were restarted in the more than seven years after the accident in Fukushima,” Akio Takahashi, president of the forum and former senior official at Tokyo Electric Power Co., said at a news conference. “I guess respondents think it’s difficult (to achieve the goal) given the current pace (of the restarts).”
Tougher nuclear safety standards were set after the Fukushima disaster, forcing utilities to spend more on upgrading their reactors or keeping aging units operational.
Asked why they thought the government’s nuclear goal was unrealistic, 48 percent of the companies said, “There are no plans in sight to build or replace nuclear reactors.”
Thirty-three percent cited the delays in restarting idle reactors, while 16 percent said, “No progress can be seen in regaining trust from the public.”
Distrust of TEPCO Hampers Decommissioning
Friday, October 19
A major challenge at the Fukushima Daiichi nuclear power plant is disposing of water containing a large amount of radioactive tritium. The Japanese government proposed diluting and releasing the water into the sea, but many fisheries in Fukushima are voicing strong opposition to the proposal. Disposal of the tainted water is a must for scrapping reactors at the plant. So, what should the government and TEPCO officials do?
Doing away with tritium-tainted water is essential
Every day, more than 100 tons of radioactive water builds up. Despite various measures taken since the 2011 accident at Fukushima Daiichi, groundwater continues to enter the reactor buildings, mixing with water which is being used to cool the reactors.
The Tokyo Electric Power Company uses a system called ALPS to treat the water. Officials have been saying that the system’s high-performance filters can get rid of most radioactive substances, except tritium.
TEPCO is not allowed to dispose of that water because its tritium levels surpass the limit set by the government.
That’s why the utility is storing 920,000 tons of the water in more than 800 tanks. The water is expected to increase by up to about 100,000 tons a year. The government and the firm say that in a matter of years, Fukushima Daiichi will run out of space for tanks.
A government panel of experts has been discussing what to do with the water. The experts concluded that the technology for separating tritium cannot be put into practical use yet. They instead put several options on the table such as:
1) Diluting and releasing the water into the sea
2) Heating and evaporating the water
3) Burying the water deep underground
A report later compiled by the panel said releasing the water into the sea will make the most sense. Experts say this is the cheapest and quickest way among all the options. The question is, is it safe?
Tritium exists in the atmosphere. The government, TEPCO and the Nuclear Regulation Authority say tritium emits a weaker form of radiation than other radioactive substances. They say that even if tritium enters the human body, it will be incorporated into water and quickly released outside. Officials say therefore, tritium is likely to pose few health risks if its concentration is low.
In the past, nuclear power plants across Japan actually released water containing tritium after confirming its readings were below the limit.
NRA Chairman Toyoshi Fuketa has been calling on the government and TEPCO to make a quick decision, saying releasing the water into the sea after its tritium level falls below the limit is the only viable option. He thinks the approval process for the proposal is unlikely to take long, so it will have limited impact on the work to scrap the reactors.
Mounting distrust among fisheries
After the expert panel compiled its report, the government held public hearings to make a final decision. At a hearing held in the town of Tomioka in Fukushima Prefecture on August 30th, the proposal came under fire mainly from people in the fishing industry.
The head of the Fukushima Prefectural Federation of Fisheries Cooperative Associations said the proposed move will be a devastating blow to the local fishing industry. He said its past efforts will go to waste, and it will deprive the industry of its motivation for rebuilding businesses.
Fishermen in Fukushima suspended their operations after radioactive materials exceeding the government-set limits were detected in seafood caught off the prefecture following the 2011 accident. But in recent years, no fish from the area have been found to be highly radioactive. Now, fishermen can catch and ship most kinds of fish.
However, some consumers still hesitate to eat marine products from Fukushima. Fish landings are still about one-tenth of levels before the accident. Local fisheries fear that if TEPCO releases the water into the ocean, they will have to delay their plans to resume operations at full capacity and struggle again to make ends meet — even if the water is deemed safe.
The underlying problem is distrust towards the government and TEPCO. There have been numerous instances in which TEPCO withheld the fact that tainted water had leaked into the sea. Locals saw them as acts of betrayal. They fear that once TEPCO begins dumping the water into the sea, consumers may refrain from purchasing fishery products from Fukushima Prefecture even further.
Public distrust further deepened during the hearings. It came to light that the water stored in some of the tanks contains levels of radioactive substances, such as iodine that exceed the limit. This contradicts the explanation given by the government and TEPCO — that the water treatment system can reduce all radioactive substances to a level below the limit, except for tritium.
My understanding was that tritium was the only radioactive substance in the tanks that exceeds the government-set limits. I was not the only one who was confused. Other participants also expressed concerns that TEPCO may have been concealing the facts.
TEPCO officials explained that levels of some radioactive substances could exceed the limits if the water treatment filters are used continuously. They said that’s not a problem, adding that the goal is to reduce the risk of radiation exposure, and that they have been making the data public on their website.
After hearing this, I checked TEPCO’s website once again. There, I found the iodine levels, but they were buried in a massive amount of data, making it very difficult to find. TEPCO officials didn’t seem eager to provide a full explanation of what has happened so far.
But TEPCO’s claim that this isn’t a problem differs with the public’s view. Its attitude is worsening the problem.
TEPCO officials tend to make decisions based on technical considerations, which often fail to sufficiently acknowledge the concerns of the locals. The officials also appear reluctant to release information that is inconvenient for them. Unless they change their mindset, they will not be able to regain the public’s trust.
Steps TEPCO must take to regain trust
First and foremost, the government and TEPCO must provide thorough explanations and responses to the questions and opinions expressed in the hearings. They need to clarify why they didn’t proactively explain the level of radioactive substances and provide their exact levels and how they will deal with them.
In addition, the government should hold public hearings at various other locations and communicate more with the public. The latest round of public hearings was held only in Fukushima and Tokyo and this didn’t seem sufficient to regain public support.
Decommissioning of the crippled Fukushima Daiichi nuclear plant is a prerequisite for the reconstruction of areas devastated by the nuclear disaster. To this end, treatment of contaminated water is a must, and it needs be done swiftly. However, there will not be progress, no matter which method is taken, without the consent of the people affected by the nuclear disaster.
TEPCO and government officials must offer truthful updates as soon as they happen. While this sounds obvious, it’s the only way to regain people’s trust and resolve the problem of the accumulation of tainted water.
Work starts to decommission problem-plagued Monju reactor
“The Japan Atomic Energy Agency (JAEA) on Aug. 30 started work to decommission the Monju prototype fast-breeder reactor in Fukui Prefecture…
The decommissioning work is scheduled to take 30 years and cost $ 3.33 billion.”
Staff members of the Japan Atomic Energy Agency operate equipment to remove nuclear fuel assemblies from a storage tank at the plant of the Monju prototype fast-breeder reactor in Tsuruga, Fukui Prefecture, on Aug. 30.
August 30, 2018
The Japan Atomic Energy Agency (JAEA) on Aug. 30 started work to decommission the Monju prototype fast-breeder reactor in Fukui Prefecture, a once-promising project that struggled with problems, even in preparations for its dismantlement.
The work started a month later than scheduled because of a series of equipment trouble. The JAEA workers also face an enormous challenge because Japan has no experience in decommissioning a fast-breeder reactor.
The JAEA will use overseas experiences as a reference for the delicate process.
Before the start of the work, JAEA President Toshio Kodama told staff members in a speech at the plant in Tsuruga, “I want you to tackle this work by bracing yourselves.”
Monju had been a key facility in the government’s nuclear fuel recycling program.
Construction of the reactor started in 1985, but a series of accidents, including a sodium coolant leak in 1995, as well as cover-ups kept the reactor offline for most of its life.
In 2016, after 1 trillion yen ($9 billion) had been spent on the project, the government finally decided to abolish Monju.
The decommissioning work is scheduled to take 30 years and cost 375 billion yen.
One of the riskiest parts in the decommissioning process is handling the liquid sodium, which reacts strongly with water and air.
In the first of the four-stage decommissioning project, the JAEA will transfer 530 nuclear fuel assemblies, currently kept in the liquid sodium-filled nuclear reactor and storage tank, to a water-filled pool by fiscal 2022.
In the work that began on Aug. 30, the JAEA will remove 160 nuclear fuel assemblies from the storage tank, wash away the sodium, and place them in the pool.
From 2019, the agency will transfer nuclear fuel assemblies from the reactor to the storage tank and then to the pool.
In December this year, the JAEA will also start to transfer about 760 tons of sodium, which has not been exposed to radioactive substances, to its storage tank. Later, the agency will remove about 910 tons of radioactive sodium from the reactor and other equipment.
In the following stages, the agency will dismantle the nuclear reactor, the turbine and other facilities.
However, no decision has been made on how to dispose of the nuclear fuel removed from the reactor and the storage tank. Monju has used mixed oxide (MOX) fuel, which contains plutonium and currently cannot be reprocessed in Japan.
“It’s realistic to ask an overseas company to reprocess it,” said Toyoshi Fuketa, chairman of the Nuclear Regulation Authority, the government’s nuclear watchdog.
If reprocessing expenses in a foreign country are added, the overall decommissioning costs will sharply increase.
Foreign Trainees for Fukushima Clean-Up
Japanese firms used foreign trainees for Fukushima clean-up
13 July, 2018
Vietnamese in Japan for professional training were among those picking up soil as part of decontamination work at the crippled nuclear power plant
Four Japanese companies made foreign trainees who were in the country to learn professional skills take part in decontamination work after the Fukushima nuclear disaster, the government said on Friday.
The discovery is likely to revive criticism of the Technical Intern Training Programme, which has been accused of placing workers in substandard conditions and jobs that provide few opportunities for learning.
The misconduct was uncovered in a probe by the Justice Ministry conducted after three Vietnamese trainees were found in March to have taken part in clean-up work in Fukushima.
The Vietnamese were supposed to do work using construction machines according to plans submitted by the company.
“But they joined simple clean-up work such as removing soil without machines,” an official said.
A powerful earthquake in March 2011 spawned a huge tsunami that led to meltdowns at the Fukushima nuclear plant, causing the world’s worst such accident since Chernobyl in 1986.
One of the four companies has been slapped with a five-year ban on accepting new foreign trainees as it was found to have paid only 2,000 yen (US$18) per day to the trainees out of the 6,600 yen provided by the state as a special allowance for decontamination work.
The ministry is still investigating how many trainees in the other three firms were involved.
The four companies cited in the interim report no longer send foreign trainees to help with the radiation clean-up. It did not name the four firms.
The ministry has finished its investigation into 182 construction companies that hire foreign trainees, and will look into another 820 firms by the end of September.
Japan has been accepting foreign trainees under the government programme since 1993 and there were just over 250,000 in the country in late 2017.
But critics say the trainees often face poor working conditions including excessive hours and harassment.
The number of foreign trainees who ran away from their employers jumped from 2,005 in 2012 to 7,089 in 2017, according to the ministry’s survey. Many cited low pay as the main reason for running away.
The investigation comes as Japan’s government moves to bring more foreign workers into the country to tackle a labour shortage caused by the country’s ageing, shrinking population.
The government in June said it wanted to create a new visa status to bring in foreign workers, with priority given to those looking for jobs in sectors such as agriculture that have been hardest hit by the labour shortage.
The workers would be able to stay for up to five years, but would not be allowed to bring their family members.
The government put the number of foreign workers in Japan in 2017 at 1.28 million people.
But more than 450,000 of those are foreign spouses of Japanese citizens, ethnic Koreans long settled in Japan, or foreigners of Japanese descent, rather than workers coming to Japan simply for jobs. Another nearly 300,000 are students.
Japan firms used Vietnamese, foreign trainees at Fukushima cleanup
July 14, 2018
Four Japanese companies have been found to made foreign trainees take part in decontamination work after the Fukushima nuclear disaster.
The discovery is likely to revive criticism of the foreign trainee program, which has been accused of placing workers in substandard conditions and jobs that provide few opportunities for learning, the government said Friday.
The misconduct was uncovered in a probe by the Justice Ministry conducted after three Vietnamese trainees, who were in the country to learn professional skills, were found in March to have participated in cleanup work in Fukushima.
The Vietnamese were supposed to do work using construction machines according to plans submitted by the company.
“But they joined simple cleanup work such as removing soil without machines,” an official told AFP.
A powerful earthquake in March 2011 spawned a huge tsunami that led to meltdowns at the Fukushima nuclear plant, causing the world’s worst such accident since Chernobyl in 1986.
The justice ministry said after the discovery this March that decontamination work was not appropriate for foreign trainees.
One of the four companies has been slapped with a five-year ban on accepting new foreign trainees, and the ministry is still investigating how many trainees in the other three firms were involved.
The ministry has finished its investigation into 182 construction companies that hire foreign trainees, and will look into another 820 firms by the end of September.
Japan has been accepting foreign trainees under the government program since 1993 and there were just over 250,000 in the country in late 2017.
But critics say the trainees often face poor work conditions including excessive hours and harassment.
The number of foreign trainees who ran away from their employers jumped from 2,005 in 2012 to 7,089 in 2017, according to the ministry survey. Many cited low pay as the main reason for running away.
The investigation comes as Japan’s government moves to bring more foreign workers into the country to tackle a labor shortage caused by the country’s aging, shrinking population.
The government in June said it wanted to create a new visa status to bring in foreign workers, with priority given to those looking for jobs in sectors such as agriculture that have been hardest hit by the labor shortage.
The workers would be able to stay for up to five years, but would not be allowed to bring their family members.
The government put the number of foreign workers in Japan in 2017 at 1.28 million people.
But more than 450,000 of those are foreign spouses of Japanese citizens, ethnic Koreans long settled in Japan, or foreigners of Japanese descent, rather than workers coming to Japan simply for jobs. Another nearly 300,000 are students.
TEPCO to decommission Fukushima Daini plant
Tokyo Electric Power Company has revealed a plan to consider decommissioning all the reactors at its Fukushima Daini nuclear plant.
It is located about 12 kilometers south of the Fukushima Daiichi plant, which was critically damaged by the March 2011 earthquake and tsunami. All 4 reactors at the Daini plant have been halted since the disaster.
TEPCO President Tomoaki Kobayakawa informed Fukushima Governor Masao Uchibori of the plan at the prefectural government office on Thursday.
Kobayakawa noted that there have been negative rumors about Fukushima, and many evacuees are still unable to return home.
He told Uchibori his company has decided that keeping the Daini plant idle would hamper the reconstruction efforts in the prefecture.
The Fukushima prefectural assembly had adopted a petition to scrap the reactors at the Daini plant.
The municipal assemblies in Tomioka and Naraha, the towns that host the facility, have adopted a similar demand. The governor has repeatedly asked TEPCO and the central government in Tokyo to arrange the early decommissioning of the plant.
The utility, however, had refrained from saying clearly whether it would decommission the plant, citing the need to consider the government’s energy policies and the business environment.
TEPCO is now expected to scrap all 10 reactors in Fukushima Prefecture — 6 at the Daiichi plant and 4 at the Daini plant.
Remediating Fukushima—“When everything goes to hell, you go back to basics”
5/11/2018
It may take 40 years for the site to appear like “a normal reactor at the end of its life.”
A schematic of the Fukushima nuclear power plant hints at the complexity of decontamination and decommissioning operations.
TEPCO workers survey operations at reactor buildings.
Seven years on from the Great East Japan Earthquake of March 2011, Fukushima Daiichi nuclear power plant has come a long way from the state it was reduced to. Once front and center in the global media as a catastrophe on par with Chernobyl, the plant stands today as the site of one of the world’s most complex and expensive engineering projects.
Beyond the earthquake itself, a well understood series of events and external factors contributed to the meltdown of three of Fukushima’s six reactors, an incident that has been characterized by nuclear authorities as the world’s second worst nuclear power accident only after Chernobyl. It’s a label that warrants context, given the scale,
complexity, and expense of the decontamination and decommissioning of the plant.
How does a plant and its engineers move on from such devastation? The recovery initiatives have faced major challenges, constantly being confronted by issues involving radioactive contamination of everything from dust to groundwater. And those smaller issues ultimately complicate the remediation effort’s long-term goal: to locate and remove the nuclear fuel that was in the reactors.
A sense of scale
Jonathan Cobb, spokesperson for the World Nuclear Association, spoke with Ars about the scale of Fukushima, explaining that radioactive releases in Japan were much smaller than at Chernobyl, and the accident resulted in no loss of life from radiation: “Of course, this doesn’t take away from the enormous task currently being faced at Fukushima.”
The UN Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) reported in May 2013 that radiation exposure following the Fukushima accident didn’t cause any immediate health effects and that future health effects attributable to the accident among either the general public or the vast majority of workers are unlikely. A 2017 paper from UNSCEAR reports that these conclusions remain valid in light of continued research since the incident.
Even the most at-risk citizens, those living in Fukushima prefecture, are only expected to be exposed to around 10mSv as a result of the accident over their lifetimes. “For reference, the global average natural background radiation tends to be around 2.4mSv/year, but even 20mSv/year isn’t exceptional,” said Cobb.
Still, the accident was rated a 7 on the International Nuclear and Radiological Event Scale (INES), which is the highest rating possible, and designates it a Major Accident due to high radioactive releases. Estimates vary slightly, but Japan’s Nuclear Safety Commission report puts total releases at 570 petabecquerels (PBq) iodine-131 equivalent. (For comparison, Chernobyl released 5,200PBq iodine-131 equivalent.)
But the severity of the accident is probably most keenly felt in the scale of the cleanup. The incident has necessitated the ongoing cleanup and decommissioning of the plant—something that Tokyo Electric Power Company (TEPCO), the plant’s owner and operator, is responsible for. Even though the plant is seven years into the cleanup and has accomplished a great deal, we won’t see a conclusion for decades yet.
Damage to reactor Units 1-4 in the aftermath of the March 2011 earthquake.
In addition to damage to infrastructure and buildings, a large amount of wreckage was left strewn around the plant complex.
Remotely operated machines were involved in clean-up of the most contaminated areas.
A look inside the Primary Containment Vessel (PCV) of Unit 2.
A composite image of photographs taken inside the Primary Containment Vessel (PCV) of Unit 2.
A look at debris in the spent fuel pool of Unit 3.
Meltdowns and immediate priorities
Remarkably, seismic shocks of the magnitude 9 earthquake didn’t cause any significant damage to the earthquake-proofed reactors; rather, the tsunami knocked out power that precipitated reactor meltdowns in Units 1, 2, and 3. Subsequent explosions caused by hydrogen buildup (from zirconium cladding of fuel assemblies melting and oxidizing) in Units 1, 3, and 4 then expelled radioactive contamination, most of which fell within the confines of the plant.
Cobb explained that in the aftermath of this, the ongoing risk posed by radionuclides (notably, iodine-131 and cesium isotopes 134 and 137) depended on their half-lives. Iodine-131, with a half-life of just eight days, posed virtually no threat at all after just several months. It has been cesium-134, with a two-year half-life, and cesium-137, with a 30-year half-life, that have been the major focus of decontamination efforts. “Radioactive decay means that we’ve seen a reduction in contamination simply through time passing; at the plant, however, my expectation is that the majority of reduction has been due to efforts of TEPCO. Conditions have improved markedly and a sense of normalcy has returned.”
It’s useful to take stock of what TEPCO had to contend with from the outset. Lake Barrett, a veteran of the US nuclear energy industry who spent several years at the helm of decommissioning work at Three Mile Island reactor 2, is currently an independent special advisor to the Japanese Government and TEPCO board of directors. He told Ars, “When everything goes to hell on you, you go back to basics. You’re concerned with accident response and immediate recovery of the situation. Over the longer timeframe, the decontamination & decommissioning (D&D) focus shifts to a more deliberate approach to major technical challenges.”
Barrett explained that reactor stabilization at Fukushima—an imperative of the immediate recovery—has long since been achieved. Temperatures within the Reactor Pressure Vessels (RPVs) and Primary Containment Vessels (PCVs) of Units 1-3 are stable at between 15 to 30ºC, and there have been no significant changes in airborne radioactive materials released from reactor buildings. This qualifies as a ‘comprehensive cold shutdown’ condition.
Barrett explained how the issue of cooling is mostly non-existent at this point: “The three melted reactor cores emit less heat than a small car. Decay heat was a huge issue in the first weeks, but it’s no longer an issue. And while TEPCO still injects water onto the cores, this is more for dust suppression than anything else.”
With the reactors stable, early phases of TEPCO’s work simply involved debris clearing and restorative efforts throughout buildings and across the 3.5 square miles of the plant—both having been ravaged by the earthquake and tsunami. In the most contaminated places, remotely operated machines undertook most of the work. To reduce environmental contamination, they also removed top soils and vegetation, deforested the site, and then applied a polymer resin and concrete across much of the plant complex. This has locked contaminated material in place and limited the flow of groundwater through the site.
Other work has been more substantial. Units 1, 3 and 4 were blown apart and have had to be reinforced and encased, both for safety and to prevent spread of radioactive material. Although Unit 2 retained its roof, TEPCO decided to dismantle the upper building nonetheless, as it will facilitate removal of fuel from the reactor.
At the peak of these operations, some 7,450 persons worked at Fukushima. As operations have evolved, the workforce has declined to a not inconsiderable 5,000 daily personnel. With such levels of permanent staffing, it’s little wonder that a new rest-house, cafeteria, shops, and office building have all been built.
The efforts have, in a practical sense, meant that the majority of the site has transitioned to a stable, relatively risk-free environment. Describing the decommissioning as an “enormous challenge never before undertaken by humanity,” Seto Kohta of TEPCO told Ars: “We have overcome the state of chaos that ensued after the accident and have succeeded in reducing site dose levels to an average of less than 5μSv/h, with the exception of the vicinity of Units 1-4.” (Global background levels are <0.5µSv/h.)
TEPCO reports that the additional effective dose (i.e. additional to natural background radiation) at the plant’s boundary has declined to the target value of less than 1mSv/y.
This is not to say the plant is without signs of past problems—far from it. Felled trees sit waiting for incineration; huge mounds of soil lie under tarps; buildings retain marks of past trauma; and with environmental dosage a perennial concern, close to a hundred dose-rate monitors are positioned around the site.
Kohta also noted that while “95 percent of the site no longer requires the donning of full- or half-face masks or coveralls,” some level of protection is still required for working around the plant according to three levels of contamination. The vast majority of the plant grounds are in what’s termed Zone G, which requires just generic coveralls and disposable medical masks. Zone Y provides a perimeter around the Units 1-4 and necessitates heavier-duty coveralls and either full- or half-face masks. And lastly there is Zone R, closer to and including the reactor buildings, requiring double-layered coveralls and full-face masks.
A steel structure is built around Unit 1 as part of reconstruction works.
An outer shell is constructed around Unit 1.
Reconstruction work at Unit 4.
A labyrinth of subterranean tunnels and access points lie around reactor buildings.
The Little Sunfish submersible used for investigations at Unit 3.
A TEPCO schematic illustrates measures taken to manage groundwater.
An impermeable wall constructed of interlocking columns extends along the seafront to restrict contaminated water reaching the sea.
Above ground apparatus of the frozen wall which descends 30m and surrounds Units 1-4.
A visitor to the plant performs a low-tech check on the frozen wall.
The groundwater bypass pump works to reduce the amount of water leaking into the reactor buildings.
Temporary storage tanks for water pumped up via the groundwater bypass.
Flanged tanks of the sort used for indefinite storage of tritium-laced water arrive at the docks of Fukushima nuclear power plant.
Visitors from IAEA visit the ALPS water treatment facility where radionuclides are removed from contaminated water.
Defueling of the spent fuel pool at Unit 4 was performed in a conventional manner; it won’t be so easy at other Units where radiation and damage is more severe.
The giant fuel handling machine (background) and fuel handling crane (foreground) arrive for installation at Unit 3.
The final segment of the domed containment roof is lifted into place at Unit 3.
Reactor investigations
While they’re now stable in terms of nuclear activity, Units 1-3 remain highly contaminated. As such, while the structural integrity of these buildings has been restored, relatively little work has been undertaken within them. (One notable exception is removal of contaminated water from condensers, completed last year.)
Over recent years, a variety of remotely operated devices and imaging technologies have performed investigations of these units. The intention has been to gather information on internal physical and radiological conditions of the PCVs—the heavily reinforced bell-shaped structures that host reactors. TEPCO wants, and needs, to understand what has happened inside. Some things are known: once melted, fuel mixed with structural materials including steel and concrete to form something known as corium. But precisely where the corium ended up, how much there is, and whether it’s submerged are just some of the questions in play.
The International Research Institute for Nuclear Decommissioning (IRID), which was established in April 2013 to guide R&D of technologies required for reactor defueling and decommissioning, is supporting TEPCO in seeking answers. IRID is composed of multiple stakeholders, including Japanese utilities and the major nuclear vendors Hitachi, Mitsubishi, and Toshiba.
Naoaki Okuzumi, senior manager at IRID, described for Ars the investigative approaches and technologies. Early work utilized Muon tomography, which Okuzumi described as “a kind of standard practice applied to each unit… to locate high density material (fuel) within PCVs.” It yielded low-resolution data on the approximate location of corium. But with pixels representing 25cm-square cross-sections, the information has been useful only in so far as validating computational models and guiding subsequent robotic investigations.
The latter task hasn’t been easy. In addition to the challenge of navigating the dark, cramped labyrinths of tangled wreckage left behind, TEPCO has had to contend with radioactivity—the high levels act something like noise in electronic circuits. The wreckage has made access a challenge, too, although varying points of ingress have been established for each PCV.
The circumstances mean that TEPCO hasn’t been able to simply purchase an off-the-shelf kit for these investigations. ”An adaptive approach is required because the situation of each PCV is different… there is no standard with investigating the PCVs by using robots,” said Okuzumi, describing an approach that has translated into devices being specially developed and built in response to conditions of each PCV.
But they’re making progress. As recently as January 2018, corium was identified for the first time inside Unit 2 using an enhanced 13m-long telescopic probe and a revised approach designed to overcome problems encountered during investigations in 2017. The situation was hardly easier at Unit 3, where the PCV is flooded to a depth of around 6.5m. Here, it took a remotely operated, radiation-shielded submersible called ‘Little Sunfish’ to locate corium in July 2017.
Altogether the investigations—featuring a litany of robotic devices—have revealed that little fuel remains in any of the cores of Units 1-3. In Unit 2, a large amount of corium is present at the bottom of the RPV; in Units 1 and 3, almost all fuel appears to have melted through the RPVs entirely and into the concrete floor of PCVs beneath. The information is crucial, as we’ll come to see, for future deconstruction work at the reactors, but it continues to be extended as investigations continue.
PCV investigations at Unit 2
Pumps, ice-walls, and storage: Water management
One of TEPCO’s major concerns has been groundwater, which runs down from mountains west of the plant and can become contaminated by the low-lying reactors before flowing out to sea. Groundwater management has subsequently become one of TEPCO’s greatest efforts, as well as one of the most challenging of the tasks it has faced.
First off, it ought to be noted that marine environment monitoring for radionuclide concentrations near the plant and as far away as Tokyo indicate that levels are well within WHO standards. “The levels of radioactivity that have been found and can be attributed to Fukushima are absolutely dwarfed by natural levels of radioactivity in the water, or even levels of cesium that came from historic nuclear weapons testing,” noted Cobb.
Still, the effort to limit further contamination—seemingly driven as much by societal-political dynamics as safety considerations—remains paramount. To this end, measures have been deployed along three principles: remove sources of contamination, isolate water from contamination, and prevent leakage of contaminated water.
Some measures have been simple enough in design. Installation of an impermeable, underground wall along the sea front, completed in October 2015, is intended to keep groundwater that passes Units 1-4 from reaching the sea. Waterproofing pavement against rainwater is another widely applied step.
After this, solutions become more sophisticated. A groundwater bypass that intercepts and pumps up water before it reaches the reactors is a key development. This water is inspected for contamination before being discharged into the sea. By November 2017, more than 337,000 cubic meters of water had been released to the ocean in this way; this bypass reduced the amount flowing into the building basements by up to 100 tons per day and successfully reduced groundwater levels around the reactor buildings.
To further limit groundwater flow into reactors buildings, TEPCO actually froze the ground around them, creating a kind of frozen wall down to a depth of about 30 meters. Approximately 1,500 meters long, the wall is kept frozen by pipes filled with an aqueous solution of calcium chloride cooled to -30ºC. Freezing commenced in March 2016 and is now “99 percent complete,” according to Kohta.
On either side of the frozen wall, sub-drains and groundwater drains have been installed; they pump water up to keep it from reactor buildings and reaching the sea, respectively. Pumped water is purified at a purpose-built treatment facility. Barrett commented: “With water released from sub-drains and the bypass, there’s an agreement with the fishing industry that releases must be below 1,500 becquerels per liter. Negotiations took several years to agree that level was ‘clean’.”
All this has come at enormous expense, but according to TEPCO, it has been successful. Before any measures were implemented, inflow was around 400m3/day, Kohta told Ars. “The average amount of water flowing into [Units 1-4] for the period from December 2015 to February 2018, before the closure of the land-side impermeable wall, was 190m3/day, and it has decreased to 90m3/day after the closure for December 2017 to February 2018.”
At face value, it’s a sound outcome. As Kohta noted, the amount of contaminated water now being generated—a mix of groundwater, rainwater and water pumped into reactors for cooling—has decreased from about 520m3/day to about 140m3/day between last December and February. Even so, treating that amount of contaminated water is proving taxing.
Water treatment is happening at large-scale facilities that have been built onsite, including a multi-nuclide removal facility. Here, a so-called Advanced Liquid Processing System (ALPS) reduces concentrations of cesium isotopes, strontium, and other radionuclides to below legal limits for release. But one radionuclide remains: tritium.
Cobb explained: “The difficulty is that tritium is basically an isotope chemically identical to hydrogen, so it’s impractical to remove. Levels of tritium in that water are low, but nevertheless there’s great sensitivity to the suggestion that it be discharged.”
Without a feasible alternative for cleaning up the tritium, the (only) solution for ALPS-treated water has been storage. Well over a thousand tanks, each holding 1,200 cubic meters, now store tritium-laced water at the south end of the plant. Several years ago, these tanks hit the news because several were found to be leaking. Barrett acknowledged it as an unfortunate and avoidable incident resulting from use of flange-tanks. TEPCO has since moved to more sturdy welded-joint water storage tanks.
The ultimate plan for stored water is unknown; tritium has a half life of a dozen years, so physics won’t clean up the water for us. Some kind of controlled, monitored discharge—the likes of which is typical within the nuclear industry—is possible, according to Barrett.
Indeed, the International Atomic Energy Agency has endorsed such a plan, which was proposed by the Atomic Energy Society of Japan in 2013. The plan involved diluting tritiated water with seawater before releasing it at the legal discharge concentration of 0.06MBq/L and monitoring to ensure that normal background tritium levels of 10Bq/L aren’t exceeded.
Discussions at both national and international levels would need to come first. Part of the difficulty here harkens back to societal dynamics surrounding risk and contamination: “In nuclear there is no such thing as absolute zero—sensitivity goes down to the atom. This makes discussion about decontamination or levels of acceptable contamination difficult. There’s tritium in that water that’s traceable to the accident; it’s entirely safe, but for the time being, with the event still in recent memory, it’s not acceptable,” observed Barrett.
Toward permanent solutions
In some sense, much of the restoration of order at Fukushima has been superficial—necessary but concerned with handling consequences more than root causes (see, TEPCO interactive timeline). Ultimately, Fukushima’s reactors must be decommissioned.
Broadly, this work involves three phases: removing used fuel assemblies that are stored within ten-meter-deep spent fuel pools of each reactor building, management of melted-down reactors and removal of corium debris, and deconstruction of reactor buildings and the greater plant.
At Unit 4, spent fuel removal operations took around 13 months and concluded in December 2014. “When we began we didn’t know if fuel assemblies or racks were distorted. It turned out they weren’t, and we were able to remove all fuel conventionally without any issues at all. Actually, it went exceedingly well, concluding ahead of schedule and under cost,” recalled Barrett. In all, 1,533 fuel assemblies were removed and transferred to a common spent fuel pool onsite.
Spent fuel removal at Unit 4 was accomplished with conventional techniques.
Defueling of pools at Units 1 through 3, which suffered meltdowns, isn’t going to be as straightforward. For one, there’s some expectation of debris and circumstances requiring extraordinary removal procedures. “I wouldn’t be surprised if we find some structurally bent fuel assemblies caused by large pieces of concrete or steel,” said Barrett.
Additionally, although radiation in Unit 3 has been reduced sufficiently to allow rotating shifts of workers to install defueling equipment, the already painstaking operations will have to be conducted remotely. The same is likely true for Units 1 and 2.
At Unit 3, the next in line for defueling, preparation is already well underway. In addition to decontamination and installation of shielding plates, TEPCO has removed the original fuel handling crane, which had fallen into the pool seven years ago, and installed a new fuel handling crane and machine. An indication of extraordinary containment methods being used, workers have built a domed containment roof at Unit 3. TEPCO’s Kohta told Ars, “Removal of spent fuel [at Unit 3] is scheduled to begin from around the middle of 2018;” meanwhile, Unit 1 is also in a preparatory stage and Unit 2 will be handled last.
Further down the line still, corium will have to be removed from melted-down reactors. It’s a daunting task, the likes of which has never been undertaken before. The reactors held varying, but known, amounts of uranium oxide fuel, about 150 tonnes each. But how much extra mass the fuel collected as it melted through reactor vessels is uncertain.
“At TMI there was exactly 93 tonnes in the reactor. Once we were done digging out fuel debris, we’d removed 130 tonnes. At Fukushima, I expect maybe a factor of five to ten more mass in core debris. It’s an ugly, ugly mess underneath the PCVs,” suggested Barrett.
High-powered lasers, drills and core boring technologies for cutting, and strong robotic arms for grappling and removing corium are already under development, according to IRID, but precise methodologies remain undecided.
The original plan, Barrett explained, was to flood PCVs and work underwater—a conventional nuclear operations technique that affords protection from contamination. But this requires water-tight PCVs, something that cannot be practically achieved at Fukushima. Discussions also continue over whether a side or top-down entry would be best. “Altogether, we don’t have enough physical data about PCVs to commit to a final decision,” said Barrett, referring back to the need for continued PCV investigations. According to Kohta, fuel debris removal isn’t scheduled to commence before the end of 2021.
Without doubt, the road ahead of TEPCO is a long one, beset with challenges greater than those faced to date. The Mid- and Long-Term Roadmap—the Japanese state-curated document outlining the decommissioning of Fukushima—envisions operations stretching a full 30-40 years into the future. Some have suggested it’s an optimistic target, others say that the plan lacks details on key, long-term issues such as permanent solid-waste storage beyond the onsite repository currently being employed. Certainly it is the case that key decisions remain.
For his part, Barrett concluded: “I believe that the 40-year timeframe is reasonable for a scientifically based decommissioning; that’s to say, to reach a point similar to that of a normal reactor at the end of its life. That’s not reaching the point of a green field where you’d want to put a children’s school. Could it be a brown-field, industrial site, though? Yes it could. That’s a rational, reasonable end point.”
By all accounts, it is hard to gauge the costs for the Fukushima clean-up. Kohta told Ars that works completed to date have cost about 500.2 billion yen, or $4.7 billion—a tremendous sum, to be sure, but fractional compared to the estimate of 8 trillion yen ($74.6 billion) approved by the Japanese state last May for the complete decommissioning of Fukushima Daiichi.
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