Tag Archives: Unit 4 spent fuel pool Fukushima

Radioactive Water Dumping and Human Rights

In the aftermath of the Fukushima Daiichi nuclear disaster, [UN Special Rapporteurs  have] consistently raised concerns about the approaches taken by the government of Japan. UN Special Rapporteurs have been concerned that raising of “acceptable limits” of radiation exposure to urge resettlement violated the government’s human rights obligations to children.

UN Special Rapporteurs have been concerned of the possible exploitation of migrants and the poor for radioactive decontamination work. Their most recent concern is how the government used the COVID-19 crisis to dramatically accelerate its timeline for deciding whether to dump radioactive wastewater accumulating at Fukushima Daiichi in the ocean

The communities of Fukushima, so devastated by the tragic events of March 11, 2011, have expressed their concerns and opposition to the discharge of the contaminated water into their environment. It is their human right to an environment that allows for living a life in dignity, to enjoy their culture, and to not be exposed deliberately to additional radioactive contamination. Those rights should be fully respected and not be disregarded by the government in Tokyo. The discharge of nuclear waste to the ocean could damage Japan’s international relations. Neighboring countries are already concerned about the release of large volumes of radioactive tritium and other contaminants in the wastewater.

Japan has a duty under international law to prevent transboundary environmental harm. More specifically, under the London Convention, Japan has an obligation to take precaution with the respect to the dumping of waste in the ocean.

Indigenous peoples have an internationally recognized right to free, prior and informed consent. This includes the disposal of waste in their waters and actions that may contaminate their food. No matter how small the Japanese government believes this contamination will be of their water and food, there is an unquestionable obligation to consult with potentially affected indigenous peoples that it has not met…The disaster of 2011 cannot be undone. However, Japan still has an opportunity to minimize the damage…There are grave risks to the livelihoods of fishermen in Japan and also to its international reputation. Again, I urge the Japanese government to think twice about its legacy: as a true champion of human rights and the environment, or not.

Excerpts from, Baskut Tuncak [UN Rapporteur], Fukushima nuclear waste decision also a human rights issue, Kyodo News, July 8, 2020

Forever Fukushima: Cleaning Up the Huge Mess

By the end of 2019, Japan further delayed the removal of thousands of spent fuel units that remain in cooling pools since the 2011 disaster The government and the plant operator, Tokyo Electric Power Co., are keeping a 30- to 40-year completion target.

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.

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…. 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.

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… The first decade through 2031 is a crucial phase that will affect future progress…

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.

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.

More than 10,000 workers will be needed annually in coming years, about one third assigned to work related to the radioactive water. 

Excerpts from MARI YAMAGUCHI,  Japan revises Fukushima cleanup plan, delays key steps, Associated Press, Dec. 27, 2019

The Enormous Task of Nuclear Waste Storage

“The Koeberg spent fuel pool storage capacity in South Africa  is currently over 90% full. (These) pools will reach (their) capacity by April 2020,” Eskom, the South African utility, told Reuters in a statement on Nov. 25, 2019.  Koeberg produces about 32 tonnes of spent fuel a year. Fuel assemblies, which contain radioactive materials including uranium and plutonium that can remain dangerous for thousands of years, are cooled for a decade under water in spent fuel pools.

Fuel Pool at Koeberg, South Africa

In 2016,  Eskom paid an estimated 200 million rand ($13.60 million) for an initial batch of seven reinforced dry storage casks from U.S. energy company Holtec International to help keep Koeberg running beyond 2018.  Eskom now has nine new unused casks on site, each with an individual capacity of 32 spent fuel assemblies, with another five expected to be delivered soon.

Holtec Cask

The 14 casks should ensure there is sufficient storage in the spent fuel pool until 2024, Eskom said, ahead of a tender for an extra 30 casks….Anti-nuclear lobby group Earthlife Africa said South Africa could not afford the social, environmental and economic costs associated with nuclear waste.  “We have a ticking bomb with high-level waste and fuel rods at Koeberg,” said Makoma Lekalakala, Earthlife Africa’s director.

Wendell Roelf, Waste storage at Africa’s only nuclear plant brimming, Reuters, Nov. 25, 2019

Never-Ending CleanUp: Fukushima

 The operator of Japan’s wrecked Fukushima nuclear plant completed in April 2019 the removal of the first fuel rods from a cooling pool high up in a badly damaged reactor building, a rare success in the often fraught battle to control the site.  The batch of 22 unused fuel assemblies, which each contain 50-70 of the fuel rods, was transferred by a trailer to a safer storage pool, the last day of a four-day operation, Tokyo Electric Power Co, or Tepco, said in a statement.

The company must carefully pluck more than 1,500 brittle and potentially damaged assemblies from the unstable reactor No.4., the early stages of a decommissioning process following the 2011 earthquake and tsunami that wrecked the site.

Tepco estimates removing the damaged assemblies from reactor No.4 alone will take a year. Some experts say that timeline is ambitious.  Still, it is an urgent operation. They are being stored 18 meters (59 feet) above ground level in a building that has buckled and tilted and could collapse if another quake strikes.  Carefully plucking the damaged fuel assemblies from the reactor building is being seen as a test of Tepco’s ability to move ahead with decommissioning the whole facility – a task likely to cost tens of billions of dollars and take decades.  The removal has to be conducted under water. If the rods are exposed to air or if they break, huge amounts of radioactive gases could be released into the atmosphere. Each assembly weighs around 300 kg (660 pounds) and is 4.5 meters (15 feet) long.  The hazardous removal operation has been likened by Arnie Gundersen, a veteran U.S. nuclear engineer and director of Fairewinds Energy Education, to trying to pull cigarettes from a crushed pack

Exerpts from In Start of Long Operation, Fukushima Removes First Fuel Rods, Reuters, April 2019

Devil’s Idea for Tokyo’s End: Fukushima

By late March 2011… after tsunami struck the Fukushima Daiichi plant—it was far from obvious that the accident was under control and the worst was over. Chief Cabinet Secretary Yukio Edano feared that radioactive material releases from the Fukushima Daiichi plant and its sister plant (Fukushima Daini) located some 12 km south could threaten the entire population of eastern Japan: “That was the devil’s scenario that was on my mind. Common sense dictated that, if that came to pass, then it was the end of Tokyo.”

Prime Minister Naoto Kan asked Dr. Shunsuke Kondo, then-chairman of the Japanese Atomic Energy Commission, to prepare a report on worst-case scenarios from the accidenta .  Dr. Kondo led a 3-day study involving other Japanese experts and submitted his report (Kondo, 2011) to the prime minister on March 25, 2011. The existence of the report was initially kept secret because of the frightening nature of the scenarios it described. An article in the Japan Times quoted a senior government official as saying, “The content [of the report] was so shocking that we decided to treat it as if it didn’t exist.” …

One of the scenarios involved a self-sustaining zirconium cladding fire in the Unit 4 spent fuel pool. Radioactive material releases from the fire were estimated to cause extensive contamination of a 50- to 70-km region around the Fukushima Daiichi plant with hotspots significant enough to require evacuations up to 110 km from the plant. Voluntary evacuations were envisioned out to 200 km because of elevated dose levels. If release from other spent fuel pools occurred, then contamination could extend as far as Tokyo,…There was particular concern that the zirconium cladding fire could produce enough heat to melt the stored fuel, allowing it to flow to the bottom of the pool, melt through the pool liner and concrete bottom, and flow into the reactor building.

Lessons Learned from the Fukushima Daiichi Accident for Spent Fuel Storage: The U.S. nuclear industry and its regulator should give additional attention to improving the ability of plant operators to measure real-time conditions in spent fuel pools and maintain adequate cooling of stored spent fuel during severe accidents and terrorist attacks. These improvements should include hardened and redundant physical surveillance systems (e.g., cameras), radiation monitors, pool temperature monitors, pool water-level monitors, and means to deliver pool makeup water or sprays even when physical access to the pools is limited by facility damage or high radiation levels….

[At nuclear power plants there must be…adequate separation of plant safety and  security systems so that security systems can continue to function independently if safety systems are damaged. In particular, security systems need to have independent, redundant, and protected power sources…]

Excerpts from Lessons Learned from the Fukushima Accident for Improving
Safety and Security of U.S. Nuclear Plants: Phase 2, US National Academies, 2016

Nuclear Robots

Robots have been used in nuclear facilities for a long time.Scenarios such as maintenance tasks in nuclear facilities or even disasters like radioactive leaks or search and rescue operations have proven to be quite successful. We are talking about robotic  arms or remote operated vehicles with some end effectors built in to handle dangerous situations.”

1986: Chernobyl’s robot trouble–During the Chernobyl nuclear incident, the Soviet authorities in charge of cleaning up nuclear waste developed around 60 unique remote-controlled robots to spare human workers from radioactive exposure. The total cost of the clean-up operation was $2bn.  Designs included the STR-1 robot, which resembles a moon buggy. It was placed on the roof of the nuclear plant and used to clean upparts of the destroyed reactor. Another design for the purpose of debris cleaning was the Mobot, developed by Moscow State University. It was a smaller version of a loader used in construction, with a front-end bucket used to  scoop up debris.

The problem was that cleaning up nuclear waste required more skills than the robots could provide, eventually resulting in the authorities sending in soldiers to perform most of the decontamination works. Radiation was so high that each worker could only spend 40 seconds inside or near the facility; 31 died from exposure, while 237 suffered from acute radiation sickness.

2008: Cleaning up nuclear waste at Hanford Nuclear Reservation. The Hanford Nuclear Reservation in the US has been somewhat of a hub for nuclear waste innovation. This is because scientists, and their robot friends, are faced with the task of emptying nuclear and chemical waste tanks the size of around 150 basketball courts before the waste reaches the Columbia River. Exposure to the material would kill a human instantly.

Luckily, Hanford has developed a few automated machines thatare specifically designed for different parts of the job. Take Foldtrack, for example, which can access the tanks through one-foot-wide pipes in the roof bysplitting into a string of pieces, and then rebuilding itself like a Transformer once inside. The remote-controlled robot uses a 3,000psi water cannon to blast nuclear sludge off the walls of the tank and pump it out. Upon completion, scientists are forced to leave the $500,000 robot in the tank due to the high levels of contamination.

Another robot, the Sand Mantis, looks like a fire hose on wheels. However, it comes packed with power, with the ability to blast tough toxic salts that build up in waste tanks with its 35,000psi water cannon. For comparison, a regular firehose has around 300psi of pressure. In order to support the huge power, the orifice of the hose is made of gems, such as sapphires, which can withstand the pressure….Finally, the Tandem Synthetic Aperture Focusing Technique,or Tank Crawler, locates cracks or corrosion in Hanford’s waste storage tanks using ultrasonic and electrical conductivity sensors.

2011: Fukushima—Previously designed robots failed to visually inspect the reactor, either breaking due to high radiation or by getting stuck in the confined spaces. That was until Toshiba’s senior scientist in its technology division, Kenji Matsuzaki, developed the Little Sunfish – an amphibious bread loaf-sized robot that could slip into the 5.5-inch reactor pipelines.

In 2017,  the Sellafield nuclear site in the UK, scientists have been working on methods to clean up the vast amounts of nuclear sludge from its First-Generation Magnox Storage Pond, as part of decommissioning efforts said to cost around £1.9bn each year. The size of two Olympic swimming pools, the storage pond contains large amounts of nuclear sludge from decaying fuel rods stored below the surface.  While robots have been designed to reach the depths of the pond and remove nuclear waste, none proved to be very successful, until Cthulhu– Collaborative Technology Hardened for Underwater and Littoral Hazardous Environment.  Cthulhu is a tracked robot that can move along the bottom ofthe storage pond, using whisker-like sensors and sonar to identify and retrieve the nuclear rods.

2018:  The South West Nuclear Hub at the University of Bristol inthe UK is collaborating with Sellafield to develop a nuclear waste robotic suit for humans, taking inspiration from the comic book hero Iron Man.

Excepts from Cherno-bots to Iron Man suits: the development of nuclear waste robotics,, Power-Technology. com, Dec. 4, 2018

Nuclear Waste at Fukushima: total amount

Each form of waste at the Fukushima Daiichi Nuclear Power Station, where three reactors melted down after an earthquake and a tsunami on March 11, 2011, presents its own challenges.

400 Tons of Contaminated Water Per Day
The Tokyo Electric Power Company is pumping water nonstop through the three reactors to cool melted fuel that remains too hot and radioactive to remove. About 400 tons of water pass through the reactors every day, including groundwater that seeps in. The water picks up radiation in the reactors and then is diverted into a decontamination facility.  But the decontamination filters cannot remove all the radioactive material. So for now, all this water is being stored in 1,000 gray, blue and white tanks on the grounds. The tanks already hold 962,000 tons of contaminated water, and Tokyo Electric is installing more tanks. It is also trying to slow the flow of groundwater through the reactors by building an underground ice wall.

Within a few years, though, and no one is sure exactly when, the plant may run out of room to store the contaminated water. “We cannot continue to build tanks forever,” said Shigenori Hata, an official at the Ministry of Economy, Trade and Industry.  The authorities are debating whether it might be acceptable, given the relatively low radioactive levels in the water, to dilute the contaminated water and then dump it into the ocean. But local fishermen are vehemently opposed. Many people still do not trust Tokyo Electric because of its bungled response to the disaster, the worst nuclear accident since Chernobyl.

3,519 Containers of Radioactive Sludge
The process of decontaminating the water leaves radioactive sludge trapped in filters, which are being held in thousands of containers of different sizes.Tokyo Electric says it cannot quantify the amount of radioactive sludge being generated. But it says it is experimenting with what to do with it, including mixing it with cement or iron. Then it will have to decide how to store it.

64,700 Cubic Meters of Discarded Protective Clothing
The estimated 6,000 cleanup workers at the site put on new protective gear every day. These hazmat suits, face masks, rubber gloves and shoe coverings are thrown out at the end of each shift. The clothing is compressed and stored in 1,000 steel boxes stacked around the site.To date, more than 64,700 cubic meters of gear has been discarded, the equivalent of 17 million one-gallon containers. Tokyo Electric says it will eventually incinerate all this contaminated clothing to reduce the space needed to store it.

Branches and Logs From 220 Acres of Deforested Land
The plant’s grounds were once dotted with trees, and a portion was even designated as a bird sanctuary. But workers have cleared about 220 acres of trees since the meltdown spewed radiation over them.Now, piles of branches and tree trunks are stacked all over the site. Officials say there are about 80,000 cubic meters of this waste, and all of it will have to be incinerated and stored someday.

200,400 Cubic Meters of Radioactive Rubble
Explosions during the meltdown filled the reactors with rubble. Workers and robots are slowly and carefully trying to remove this tangled mass of crushed concrete, pipes, hoses and metal.  Tokyo Electric estimates that more than 200,400 cubic meters of rubble — all of it radioactive — have been removed so far and stored in custom-made steel boxes. That is the equivalent of about 3,000 standard 40-foot shipping containers.

3.5 Billion Gallons of Soil

Thousands of plastic garbage bags sit in neat rows in the fields and abandoned towns surrounding the Fukushima plant. They contain soil that was scraped from land that was exposed to radiation in the days after the accident.  Japan’s Ministry of the Environment estimates that it has bagged 3.5 billion gallons of soil, and plans to collect much more. It will eventually incinerate some of the soil, but that will only reduce the volume of the radioactive waste, not eliminate it.  The ministry has already begun building a massive, interim storage facility in Fukushima prefecture and negotiating with 2,360 landowners for the thousands of acres needed to complete it. And that is not even a long-term solution: The government says that after 30 years it will need another site — or sites — to store radioactive waste.

1,573 Nuclear Fuel Rods
The ultimate goal of the cleanup is to cool and, if possible, remove the uranium and plutonium fuel that was inside the three reactors at the time of the disaster.  Hundreds of spent fuel rods are in cooling pools inside the reactors, and the company hopes to have cleared away enough rubble to begin removing them next year. The much bigger challenge will be removing the fuel that was in use in the reactor core at the time of the meltdown.

The condition and location of this molten fuel debris are still largely unknown. In one reactor where a robot was sent in January, much of the melted fuel is believed to have burned through the bottom of the inner reactor vessel and burrowed into the thick concrete foundation of the containment structure.  The plan is to completely seal the containment vessels, fill them with water and use robots to find and remove the molten fuel debris. But the rubble, the lethal levels of radiation and the risk of letting radiation escape make this an exceedingly difficult task.

In January 2017, the robot sent into one of the reactors discovered radiation levels high enough to kill a person in less than a minute. Another had to be abandoned last month after debris blocked its path and radiation disabled it.

Tokyo Electric hopes to begin removing fuel debris from the reactor cores in 2021. The entire effort could take decades. Some say the radioactive material may prove impossible to remove safely and have suggested leaving it and entombing Fukushima under a concrete and steel sarcophagus like the one used at Chernobyl.

But the Japanese government and Tokyo Electric say they are committed to removing all the waste and cleaning the site, estimated at a cost of $188.6 billion.

Excerpts from MOTOKO RICH, Struggling With Japan’s Nuclear Waste, Six Years After Disaster, Mar. 11, 2017