Robots used to remove Fukushima’s highly radioactive used nuclear fuel, but they’re still problematic

Plutonium problems won’t go away, By Chris Edwards, Engineering and Technology, February 15, 2022  ”’………………………………………At a conference organised by the International Federation of Robotics Research on the 10th anniversary of the accident, Toyota Research chief scientist Gill Pratt said the first robots “got there in the overhead luggage of commercial flights”. For all of them it was a baptism of fire.

Narrow staircases and rubble turned into insurmountable obstacles for some. Those that made it further failed after suffering too much radiation damage to key sensors and memories. Finally, some developed by the Chiba Institute of Technology were able to explore the upper floors of Reactor 2. The researchers designed their Quince to work for up to five hours in the presence of a cobalt-60 source that would generate an average dose of 40 grays per hour.

Direct radiation damage was not the only problem for the Fukushima robots. Reactors are protected by thick concrete walls. Wireless signals fade in and out and fibre-optic cabling becomes an impediment in the cluttered space of a damaged building.

To be close enough to the machines, operators had to wear bulky protective clothing that made teleoperation much harder than it would be in other environments. Several robots went into the building only to fail and get stuck, turning into obstacles for other machines.

The risk of these kinds of failure played into the nuclear industry’s long-term resistance to using robots for repair and decommissioning. Plant operators continued to favour mechanical manipulators operated by humans, separated by both protective clothing and thick lead-heavy glass.

Since Fukushima, attitudes to robots in the nuclear industry have changed, but remote control remains the main strategy. Pratt says humans remain generally better at control and are far better at dealing with the unstructured environments within many older and sometimes damaged installations.

The long-term aim of those working on these systems is to provide robots with greater degrees of autonomy over time. For example, surveillance drones will be flown with operator supervision but the machines are acquiring more intelligence to let them avoid obstacles so they need only respond to simpler, high-level commands. This can overcome one of the problems created by intermittent communications. One instance of this approach was shown when UK-based Createc Robotics recently deployed a drone at Chernobyl and Fukushima, choosing in the latter case to survey the partly collapsed turbine hall for a test of its semi-autonomous mapping techniques.

To get more robots into play in the UK, the NDA has focused its procurement more heavily on universities and smaller specialist companies, some of which are adapting technologies from the oil and gas industry.

The NDA expects it will take many years to develop effective robot decommissioning and handling technologies. It has put together a broad roadmap that currently extends to 2040. Radiation susceptibility remains an issue. Visual sensors are highly susceptible to damage by ionising radiation. However, a mixture of smarter control systems and redundancy should make it possible to at least move robots to a safe point for repair should they start to show signs of failure.

Another design strategy being pursued both in the UK and Japan is to build robots as though they are a moving, smart Swiss-army knife: armed with a variety of detachable limbs and subsystems so they can adapt to conditions and possibly even perform some on-the-fly repairs to themselves.

Slowly, the technology is appearing that can handle and at least put the waste out of harm’s way for a long time, though you might wonder why the process has taken decades to get to this stage of development. ……………. (Goes on to laser developments, again, far from a sure thing.) https://eandt.theiet.org/content/articles/2022/02/plutonium-problems-won-t-go-away/

Fukushima nuclear mess 2021 – the tasks ahead

The Fukushima Nuclear Disaster: Then and Now, The Chemical Engineer 25th February 2021 by Geoff Gill 

“………..Decommissioning and contaminated water management

The work to decommission the plants, deal with contaminated water and solid waste, and remediate the affected areas is immense. A “Mid-and-Long Term Roadmap”2 was developed soon after the disaster to set out how this will be achieved. Also, to facilitate decommissioning units 1-6, and dealing with contaminated water, TEPCO announced, at the end of 2013 the establishment of an internal entity: the Fukushima Daiichi Decontamination & Decommissioning Engineering Company, which commenced operations in April 2014. The entire decommissioning process will take 30–40 years, and, as noted above, the volume of tasks is gigantic. Therefore, the Government of Japan and TEPCO have prioritised each task and set the goal to achieve them. Essentially, it is a continuous risk reduction activity to protect the people and the environment from the risks associated with radioactive substances by:

• removing spent fuel and retrieval of fuel debris from the reactor buildings;
• establishing measures to deal with contaminated water; and
• establishing measures to deal with radioactive waste material.

Fuel removal from the reactor buildings

In the Fukushima Daiichi design of reactor, used and new fuel rod assemblies are stored in the upper part of the reactor. The used fuel rods are highly radioactive and continue to generate heat, and thus require continued cooling. Depending on the degree of damage, the process of removing the fuel assemblies presents different challenges in each of the reactors. For example, one of the significant challenges is to firstly remove the large quantities of rubble caused by the hydrogen explosions. As noted above, reactors 5 and 6 were shut down at the time of the accident. The reactor cores were successfully cooled, and thus suffered no damage. Given that the conditions of the buildings and the equipment for storing the fuel are stable, and risks of causing any problem in the decommissioning process are estimated to be low compared to the other units, the fuel assemblies of units 5 and 6 continue to be safely stored in the spent fuel pool in each building for the time being. The next step will be to carefully remove the fuel from the fuel pools in units 5 and 6 without impact on fuel removal from units 1, 2 and 3. All the remaining units are going through a number of stages to achieve fuel removal. They differ slightly for each unit, but essentially the stages are: survey of internal state, removal of rubble, installation of fuel handling facility, and removal of fuel. By way of example, the position regarding unit 3 is shown in Figure 3 [on original]. At unit 3, rubble removal and other work at the upper part of the reactor building, together with installation of a cover for fuel removal was completed in February 2018. After all preparations were in place, work to remove the 566 fuel rod assemblies, including 52 non-irradiated fuel assemblies, began in April 2019. The process of fuel removal is shown diagrammatically in Figure 4. The four stages are:

• Fuel rod assemblies stored on fuel racks in the spent fuel pool are transferred in the water one at a time to transport casks, using fuel handling equipment;
• after closing the cask cover and washing, a crane is used to lower the cask to ground level and load into a trailer;
• the cask is transported to a common pool on the site; and
• the fuel in the cask is stored in the common pool.

As of 8 January 2021, 468 assemblies including the 52 non-irradiated fuel assemblies had been removed from unit 3. Measurements of airborne contamination levels are being monitored in the surrounding environment throughout the fuel removal operations. The plan is that all fuel will have been removed from all of the reactor units by sometime during 2031.

Retrieval of fuel debris

At the time of the accident, units 1–3 were operating and had fuel rods loaded in the reactors. After the accident occurred, emergency power was lost, preventing further cooling of the cores. This resulted in overheating and melting of the fuel, together with other substances. Fuel debris refers to this melted fuel and other substances, which have subsequently cooled and solidified, and, of course, still remains dangerously radioactive. This clearly poses a very complex and difficult decommissioning challenge. Currently the state inside the containment vessel is being confirmed, and various kinds of surveys are being conducted prior to retrieval of the debris. The current aim is to begin retrieval from the first unit (unit 2), and to gradually enlarge the scale of the retrieval. The retrieved fuel debris will be stored in the new storage facility that will be constructed within the site. The distribution of debris between the pressure and containment vessels differs in each of the 3 units. By way of example, Figure 5 [on original] shows the current position in unit 2. Large amounts of debris are located in the bottom of the pressure vessel, with little in the containment vessel. The investigation to capture the location of fuel debris inside unit 2 was conducted from 22 March–22 July 2016. This operation applied the muon transmission method, of which effectiveness was demonstrated in its appliance for locating the debris inside unit 1. (Muon transmission method is a technique that uses cosmic ray muons to generate three-dimensional images of volumes using information contained in the Coulomb scattering of the muons.) These operations used a small device developed through a project called “Development of Technology to Detect Fuel Debris inside the Reactor’’.  Use of remote operations for decommissionings;

• establishing measures to deal with contaminated water; and
• establishing measures to deal with radioactive waste material.

…….. Understanding of the situation inside the stricken reactors was urgently needed following the accident in order to prevent the spread of damage and to mitigate the disaster. Tasks had to be carried out in a very complicated, difficult and unpredictable environment. In particular, the environment inside the reactor buildings reached high radiation levels due to the spread of radioactive contamination. To reduce the risk of radiation exposure to operators, remote control technologies  have proved indispensable for examining the reactor buildings and subsequently for decommissioning work. Thus, remote control technology, including robot  technology has been heavily utilised in response to the accident. Figure 6 [on original]shows a typical configuration of remotely-controlled robotic systems for decommissioning work. Reducing the risks associated with contaminated water Water has posed a very demanding challenge for the operators. The problem stems from groundwater flowing from the mountain side of the site toward the ocean. This flows into the reactor buildings and becomes mixed with radioactive water accumulated in the buildings, increasing the amount of contaminated water already  there. The solution to the contaminated water problem is being tackled through a three-pronged approach. These are redirecting groundwater from contamination sources, removing contamination sources, and prevent leakage of contaminated water. In order to achieve this, barriers have been installed on the land -side and sea-side of the plant. An impermeable barrier on the land-side has been achieved by freezing the ground. The frozen soil “wall” (which has a circumference of about 1,500 m) has been achieved by piping chilled brine through pipes to a depth of 30 m, which freezes the surrounding soil. On the sea-side, a wall has been constructed, consisting of 594 steel pipes (see Figure 7   -on original)……… Purification treatment of contaminated water and management of treated water…….Treatment and disposal of solid radioactive waste Waste materials resulting from the decommissioning work are sorted based on their radiation levels and are stored on the premises of the Fukushima Daiichi  Nuclear Power Station. Along with strict safety measures and studies on treatment and disposal methods, a solid waste storage management plan is drawn up  based on waste generation forecasts for around the next ten years, so that measures to deal with waste materials will be carried out effectively The storage management plan is updated once a year, while reviewing the waste generation forecasts, taking account of progress of the decommissioning work.  The illustration in Figure 9 [on original] shows the various facilities planned for treatment and storage of solid waste. TEPCO’s Mid and Long Term Roadmap shows all these facilities being completed by 2028. The amounts of waste generated are huge. For example, the latest edition of the roadmap estimates the amount of solid waste which will be generated over the next 10 years to be 780,000 m3 …….. https://www.thechemicalengineer.com/features/the-fukushima-nuclear-disaster-then-and-now/

Fukushima’s contaminated waste water – more serious than previously thought

Fukushima’s Contaminated Wastewater Could Be Too Risky to Dump in the Ocean,   https://www.gizmodo.com.au/2020/08/fukushimas-contaminated-wastewater-could-be-too-risky-to-dump-in-the-ocean/     Dharna Noor  :August 7, 2020 Almost a decade ago, the Tohoku-oki earthquake and tsunami triggered an explosion at Japan’s Fukushima Daiichi Nuclear Power Plant, causing the most severe nuclear accident since Chernobyl and releasing an unprecedented amount of radioactive contamination in the ocean. In the years since, there’s been a drawn out cleanup process, and water radiation levels around the plant have fallen to safe levels everywhere except for in the areas closest to the now-closed plant. But as a study from the Woods Hole Oceanographic Institution published in Science on Thursday shows, there’s another growing hazard: contaminated wastewater.

Radioactive cooling water is leaking out of the the melted-down nuclear reactors and mixing with the groundwater there. In order to prevent the groundwater from leaking into the ocean, the water is pumped into more than 1,000 tanks. Using sophisticated cleaning processes, workers have been able to remove some of this contamination and divert groundwater flows, reducing the amount of water that must be collected each day. But those tanks are filling up, and some Japanese officials have suggested that the water should dumped into the ocean to free up space.

The water in the tanks goes through an advanced treatment system to remove many radioactive isotopes. The Japanese utility company TEPCO, which is handling the cleanup processes, claims that these processes remove all radioactive particles from the water except tritium, an isotope of hydrogen which is nearly impossible remove but is considered to be relatively harmless. It decays in about 12 years, which is faster than other isotopes, is not easily absorbed by marine life, and is not as damaging to living tissue as other forms of radiation.

But according to the new study, that’s not the only radioactive contaminant left in the tanks. By examining TEPCO’s own 2018 data, WHOI researcher Ken Buesseler found that other isotopes remain in the treated wastewater, including carbon-14, cobalt-60, and strontium-90. He found these particles all take much longer to decay than tritium, and that fish and marine organisms absorb them comparatively easily.  

“[This] means they could be potentially hazardous to humans and the environment for much longer and in more complex ways than tritium,” the study says.

Though TEPCO’s data shows there is far less of these contaminants in the wastewater tanks than tritium, Buesseler notes that their levels vary widely from tank to tank, and that “more than 70% of the tanks would need secondary treatment to reduce concentrations below that required by law for their release.”

The study says we don’t currently have a good idea of how those more dangerous isotopes would behave in the water. We can’t assume they will behave the same way tritium does in the ocean because they have such different properties. And since there are different levels of each isotope in each different tank, each tank will need its own assessment.

“To assess the consequences of the tank releases, a full accounting after any secondary treatments of what isotopes are left in each tank is needed,” the study said.

Buesseler also calls for an analysis of what other contaminants could be in the tanks, such as plutonium. Even though it wasn’t reported in high amounts in the atmosphere in 2011, recent research shows it may have been dispersed when the explosion occurred. Buesseler fears it may also be present in the cooling waters being used at the plant. That points to the need to take a fuller account of the wastewater tanks before anything is done to dump them in the ocean.

“The first step is to clean up those additional radioactive contaminants that remain in the tanks, and then make plans based on what remains,” he said in a statement. “Any option that involves ocean releases would need independent groups keeping track of all of the potential contaminants in seawater, the seafloor, and marine life.”

Many Japanese municipalities have been pushing the government to reconsider its ocean dumping plans and opt to find a long-term storage solution instead, which makes sense, considering exposure to radioactive isotopes can cause myriad health problems to people. It could also hurt marine life, which could have a devastating impact on fishing economies and on ecosystems.

“The health of the ocean — and the livelihoods of countless people — rely on this being done right,” said Buesseler.

The Fukushima Diiachi Accident Chain, Part 6

The Fukushima Diiachi Accident Chain, Part 6, Nuclear Exhaust, 22 July 20

A Discussion of Official Reports Describing the Fukushma Diiachi  Nuclear Disaster

 The references used for this discussion are:

“The Official report of the Fukushima Nuclear Accident Independent Investigation Commission Executive Summary”, The National Diet of Japan, 2012.

“FUKUSHIMA DAIICHI: ANS Committee Report”, A Report by The American Nuclear Society Special Committee on Fukushima, March 2012.

“The Fukushima Daiichi Accident, Technical Volume 1/5 Description and Context of the Accident, IAEA, Vienna, 2015.

 “FACT AND CAUSE OF FUKUSHIMA NUCLEAR POWER PLANTS ACCIDENT”, Hideki NARIAI, Proceedings of the International Symposium on Engineering Lessons Learned from the 2011 Great East Japan Earthquake, March 1-4, 2012, Tokyo, Japan.

Other sources, such as press reports, industry and authority regulations and technical bulletins will also be used.

The very great complexity of the disaster and of the human and systems responses to the challenges which confronted, and confront, the Fukushima Diiachi nuclear plant and the people operating and tending to the plant is obvious. The aim of this discussion is to attempt to produce, in review, a coherent picture of the events as reported by the authorities given above.

While the nuclear industry and permanent nuclear authorities – the IAEA – tend to agree closely in their reports of the events, the Fukushima Nuclear Accident Independent Investigation Commission, appointed by the Japanese national Parliament (Diet) reports various aspects of the disaster with pointedly local questioning of events based upon witness accounts and the Committee’s own findings. And these perceptions, based on local knowledge of both the plant and witness statements actually challenge, in aspects, the findings of the other authorities.

As a preamble to the discussion of the disaster, a central consideration to all nuclear power plants in use today has to be included.   The long term, intermediate term and short term safety of nuclear power plants depends upon the availability of electrical grid connection and power to the reactors and the entire plant. This is not an opinion, it is a technical fact which nuclear authorities have repeatedly reported upon.

The surprising fact is, that although nuclear reactors can supply electrical power to the world’s largest cities and nations, when the grid goes down, there is no ability for any nuclear reactor to power itself and its systems on any long term basis. There is nothing integral to the reactors which allows the energy resident in the reactors’ cores and pressure vessels to be controlled and managed so as to manage the cooling of the reactors.

While the nuclear industry and nuclear authorities have touted the virtues of nuclear power plant emergency cooling systems for over 50 years.   However:

 “The emergency cooling systems started. However, they did not work for so long time, and the fuels became to heat up and melt down, resulting the severe accident. “ Source: English translation of “FACT AND CAUSE OF FUKUSHIMA NUCLEAR POWER PLANTS ACCIDENT , Hideki NARIAI, Proceedings of the International Symposium on Engineering Lessons Learned from the 2011 Great East Japan Earthquake, March 1-4, 2012, Tokyo, Japan.

As we shall see later, the workers at the Fukushima Diiachi site during the early stages kept the emergency cooling systems going for many hours longer than the systems were designed to last. And these systems are designed to work for 8 hours only. (See the ANS report)..………. 

It is beyond me why the nuclear industry, for more then 50 years, has been so wilfully dumb, ignorant and arrogant in the design of its emergency systems. And everything else.  It seems to me the main aim of the industry is to sell reactors by any means.  Whereas the industry should have the main aim of assuring safety in the context of the modern world and the modern world energy market.   The problem is, though solar panels mounted on the Fukushima Shima Diiachi reactor building roofs could have save the day by keeping cooling pumps going, the obvious thought is this: why not just replace the Fukushima Diiachi with a solar and wind farm?  

No danger of meltdown at all.  As soon the 2009 scientific assessment came in demonstrating that an earthquake and tsunami was due “within the next 30 years”. that is precisely what should have been down.  Perhaps Barry Brook and Pam Sykes, two academic non nuclear experts in Australia, were right. No human skill could have saved Fukushima Diiachi. So why leave it there? Pity the authorities in the nuclear industry hid and suppressed the scientific warnings of 2009, including TEPCOs own confirmation of the growing threat.  This is standard procedure for the nuclear industry. It is not a particularly Japanese culture.  It is nuclear norm.

The IAEA requirements for electricity grids which supply Nuclear Power Plants.

The following text is a straight quote from : ” “ELECTRIC GRID RELIABILITY AND INTERFACE WITH NUCLEAR POWER PLANTS” IAEA NUCLEAR ENERGY SERIES No. NG-T-3.8, IAEA, ….

Quote: ““The safe and economic operation of a nuclear power plant (NPP) requires the plant to be connected to an electrical grid system that has adequate capacity for exporting the power from the NPP, and for providing a reliable electrical supply to the NPP for safe startup, operation and normal or emergency shutdown of the plant.

“Connection of any large new power plant to the electrical grid system in a country may require significant modification and strengthening of the grid system, but for NPPs there may be added requirements to the structure of the grid system and the way it is controlled and maintained to ensure adequate reliability.

“The organization responsible for the NPP and the organization responsible for the grid system will need to establish and agree the necessary characteristics of the grid and of the NPP, well before the NPP is built, so that they are compatible with each other. They will also need to agree the necessary modifications to the grid system, and how they are to be financed.

“For a Member State that does not yet use nuclear power, the introduction and development of nuclear power is a major undertaking. It requires the country to build physical infrastructure and develop human resources so it can
construct and operate a nuclear power plant (NPP) in a safe, secure and technically sound manner. ” end quote. Source: “ELECTRIC GRID RELIABILITY AND INTERFACE WITH NUCLEAR POWER PLANTS” IAEA NUCLEAR ENERGY SERIES No. NG-T-3.8, IAEA,

Hmm. very interesting. NPPs require a specifically designed and modified baseload capable grid network before they can be expected to safely start up, operation and shut down. Further the grid is needed, according to the world nuclear authority, for SAFE EMERGENCY SHUTDOWN.

The Earthquake and the Grid in Japan on the day of the disaster

One would have thought the following information would have been clearly discussed by the nuclear authorities from the day of the disaster. It’s nearly 10 years and still no word from them:

““Vibrations from the magnitude 9.0 earthquake triggered an immediate shut down of 15 of Japan’s nuclear power stations. Seismic sensors picked up the earthquake and control rods were automatically inserted into the reactors, halting the fission reaction that is used to produce electricity. This sudden loss of power across Japan’s national power grid caused widespread power failures, cutting vital electricity supplies to Fukushima Daiichi. There were three reactors, one, two and three, operating at the time when the earthquake hit while reactors four, five and six had already been shutdown as part of routine maintenance work.” “Japan earthquake: how the nuclear crisis unfolded”. Richard Gray, Science Correspondent, The Telegraph, 20 March 2011. end quote.

The first thing the earthquake did was to cause the shutdown of nuclear power feed into the grid. 15 Nuclear Power Plants threw in the towel because they cannot safely operate during an earthquake. Apparently. Nuclear power guarantees black out in an earthquake.

more https://nuclearexhaust.wordpress.com/2020/07/23/the-fukushima-diiachi-accident-chain-part-6/

The complexities and pitfalls of citizen science

One such tactic, which was witnessed after Fukushima, occurred through the reframing of radiation risks as simplistic and natural, unrelated to the specific risks associated with Fukushima. For instance, the government distributed pamphlets that explained that radiation naturally exists in our food, ch as the potassium levels present in bananas.

Yet such information is irrelevant to the hazards of internalizing fission products from a nuclear power plant. While bananas have naturally occurring potassium, it would require eating around 20 million bananas to get radiation poisoning.  On the other hand, each radionuclide released during nuclear meltdown events like Fukushima possesses specific biological signatures and presents particular risks when inhaled or ingested.

Being Clear-Eyed About Citizen Science in the Age of COVID-19, Sapiens MAXIME POLLERI / 15 JUL 2020 

“……..there are inherent political complexities involved when citizens or nongovernmental organizations step in and claim expertise in areas typically reserved for state agencies and experts. Like those entities, citizen science has its own potential pitfalls.

For one, corporate polluters or state agencies can potentially exploit citizen science, delegating the monitoring of contamination to the victims of a disaster. For instance, by the end of this year, Japan’s Nuclear Regulation Agency plans to remove 80 percent of radiation monitoring posts in Fukushima, arguing that the radiation levels in many areas have stabilized themselves—owing also in part to the presence and efficiency of monitoring networks provided by citizens. This decision has been controversial, since problems of radioactive contamination persist in Fukushima. For instance, one of the main radioactive pollutants, Cesium-137, has a long lifespan and can emit radiation for nearly 300 years.

Retiring these posts will force citizen scientists to take on the burden of monitoring, shifting liability for ensuring safe living conditions onto the shoulders of the nuclear victims. In addition, the growing impact of citizen science can lead to reduced public expenditure, minimal government intervention, and risk privatization, meaning that risk becomes individual and private. Too much delegation to citizens runs the risk of creating societies where individuals have to take care of themselves in increasingly polluted environments, while interpreting complex data about controversial environmental dangers. And not every community can afford to purchase expensive monitoring devices or test food in a consistent manner.

Citizen scientists also risk reproducing forms of ignorance around certain hazards.   n post-Fukushima Japan, what is meant by the “science” of citizen science is often synonymous with a tracking and monitoring agenda, where individuals resort to the very same technologies and knowledge forms used by states, nuclear lobbies, or radiological protection agencies.

Yet many anthropologists and historians have argued that what we know (and don’t know) about the extent of radiation hazards and dangers was embedded in a culture of secrecy, denial, and propaganda that was shaped by the nuclear arms race of the Cold War. Considerations over international security and political stability were often prioritized over the safety of workers or citizens who had been exposed to radiation. As a result, some of the negative effects of radiation were downplayed through different tactics.

One such tactic, which was witnessed after Fukushima, occurred through the reframing of radiation risks as simplistic and natural, unrelated to the specific risks associated with Fukushima. For instance, the government distributed pamphlets that explained that radiation naturally exists in our food, ch as the potassium levels present in bananas.

Yet such information is irrelevant to the hazards of internalizing fission products from a nuclear power plant. While bananas have naturally occurring potassium, it would require eating around 20 million bananas to get radiation poisoning.  On the other hand, each radionuclide released during nuclear meltdown events like Fukushima possesses specific biological signatures and presents particular risks when inhaled or ingested. During my fieldwork in Fukushima, I witnessed that this legacy of misinformation was carried on by some citizens who unwittingly replicated these propagandist forms of knowledge by making similar naturalistic or overly simplistic comparisons.

As citizen science efforts grow, it is also critical to consider to what extent citizen involvement might put individuals at risk of adverse health effects. This is a tricky question when one considers that certain members of the population, like children, are more sensitive to radiation than others. In Fukushima, some Japanese parents have understandably opted to evacuate rather than rely on citizen science, arguing that doing so would expose their children to unacceptable levels of radiation and that forcing children to be responsible for their own safety is unethical.

Citizen scientists are hardly homogeneous groups, as mothers, farmers, and urban citizens do not experience hazards and recovery in the same way. In that regard, factors such as gender, employment, and social class strongly influence why people enter citizen science, how science is mobilized, and how data about a controversial hazard ends up being interpreted. For instance, people like Natsuo have used the results gathered by citizen science to highlight the dangers of living in Fukushima, while other citizen science organizations help bring people back to their beloved region. These conflicts can result in even more fragmented communities and conflicts within and around citizen science. ……

In Japanese, two words—shiru and wakaru—can be used for the verb “knowing.” Shiru means “to find out” or “to learn.” It implies a process of acquisition of knowledge and information. Wakaru, on the other hand, is closer to “understanding this knowledge.” Shiru comes before wakaru, and in a way, one can know but not necessarily understand. Wakaru consequently shows a greater and more personal level of comprehension often based on a given context.

For Masayuki, state institutional experts possessed shiru, but not wakaru. Having been directly affected by radioactive contamination, Masayuki strongly believed that the inhabitants of a place, the jūmin (literally, the people who resided) were best suited to manage their life in a post-Fukushima Japan.  https://www.sapiens.org/culture/fukushima-citizen-science/

 

Citizen science and Fukushima radiation

Being Clear-Eyed About Citizen Science in the Age of COVID-19

An anthropologist explores the network of citizen monitoring capabilities that developed after the Fukushima nuclear disaster in Japan in 2011 for what they might teach all of us about such strategies for the covonavirus pandemic. Sapiens MAXIME POLLERI / 15 JUL 2020 “……………  The earthquake and subsequent tsunami led to core meltdowns within some of the Fukushima power plant’s nuclear reactors. This malfunction, along with other technical incidents, resulted in the atmospheric release of radioactive pollutants, which spread predominantly over the northeastern part of Japan, forcing a widespread evacuation of Fukushima residents. By March 12, the area around the power plant had been evacuated; those living and working within 20 kilometers of the radius of the plant were forced to relocate. In the days, weeks, and months following this disaster, uncertainty around the scale and extent of contamination grew swiftly—much like what we see occurring throughout the world during the COVID-19 pandemic.

Most notably, the public grew increasingly concerned about the legitimacy of institutional experts’ ability to control and explain the risks of residual radioactivity, while citizens like Natsuo were unable to get adequate information through traditional media venues. Initially, data about radioactive contamination came sporadically and was often explained in hard-to-understand metrics by scientists who were cherry-picked by the state to send reassuring messages to citizens.

Moreover, radioactive contamination was later found to be present in some food products and in school yards where children had been playing that lay beyond the official zone of evacuation. Over the ensuing months and years, the public lost confidence in the state’s response and began to take matters into their own hands, mobilizing expert practices of their own. Widespread grassroot actions led to citizen science networks in which people tracked radiation in their environment, organized learning workshops on radiation dangers, and tested food for contamination, often through local organizations or individual households.

As an anthropologist who conducted fieldwork on the Fukushima nuclear disaster between 2015 and 2017, I came to realize that citizen science can rise up to fill in the gaps of state responses toward crises, for better or for worse. As we’ve seen play out throughout the COVID-19 pandemic in various parts of the world, governance and leadership have often been confusing, mismatched, and at times utterly misleading. The case of Fukushima offers lessons about both the promises and pitfalls of citizen science and how civil society is playing an increasingly important role in managing various disasters, catastrophes, and crises.

The Geiger counter of Masayuki was not silent for long before it began to emit the distinctive “clicking” sound associated with radiation monitoring devices. The “click” grew louder in intensity as we located a hot spot, an area where the level of radiation is significantly higher than elsewhere. Masayuki dutifully noted the number provided by the device before leaving to search for another hot spot. We were standing in the Japanese village of Iitate, situated in the prefecture of Fukushima. It was common at this time for citizens to own their own Geiger counters—often purchased off the internet using international donations or made at home as DIY devices—to measure the level of radiation around them.

When I first came to this rural village in the spring of 2016, more than five years had passed since the nuclear disaster. The forced evacuation of citizens from Fukushima and the surrounding areas had proved short-lived; by 2012, the Japanese state had already embraced a policy of repatriation to irradiated areas like Iitate village, which is where I met Masayuki and citizens like him in 2016. ……….

While happy to be back in their beloved region, many residents were critical of the state radiation-monitoring networks that were supposed to provide them with adequate information to allow them to live safely in the village. Indeed, state data on radiation was often provided through fixed monitoring in precise locations or through an average radiation level taken in the village. This kind of information was not practical enough for residents, who wanted to know the specific radiation levels behind their houses or in their rice paddy fields.

Likewise, official depictions of radiation levels through clear-cut chromatic zones did little to offer the citizens reassurance. As a result of the perceived limitation of state measures, residents quickly decided to track radiation themselves as a means to keep the map of their village relevant—often finding contamination that was not evident from state mapping. In the house of one farmer, I witnessed homemade models that exhibited a 3D topography of Iitate’s geographical landscape. These models had been made using 3D printers, and the level of radiation had been monitored by the citizens themselves.

In particular, the local knowledge of the geography of Iitate helped citizens to attain a level of precision that far exceeded that of the government map. Citizens soon learned that radiation doses could be higher at the bottom of a hill than farther upslope or that the woods behind one’s home, having trapped radiation, might impact the radiation level inside houses. These practices helped strengthen a community that had previously felt helpless in the face of an imperceptible radiation threat. Geiger counters became the ears and eyes of citizens like Masayuki, enabling them to make sense of and gain some semblance of control over a hazard that cannot be registered by the senses.

After the Chernobyl nuclear disaster in 1986, one of the main sources of radiation exposure stemmed from consumption of food products such as milk or wild mushrooms that had been contaminated by radioactive fallout. In an effort to make sure that this did not happen in Japan, the government took on the task of testing the food produced in Fukushima, implementing a limit to the allowable amount of radioactivity in food products.

Within months after the meltdowns, the government assured the public of the safety of its food products, encouraging citizens to consume foods sold at public fairs and other public events. However, citizens of Fukushima also consume food harvested from streams, forests, home gardens, and mountain areas—where state monitoring was largely absent or insufficient.

Again, citizens mobilized to fill in the gaps in food testing: With the help of public donations, citizen scientists were able to purchase scintillation detectors, which are used to measure radioactive contaminants in foodstuff. Such testing enabled citizens to gain an understanding of the types of foods most prone to radioactive contamination, such as mushrooms, green leafy vegetables, citrus, sea cucumber, and seaweeds. This in turn helped people avoid eating the most risky foods. Together with state monitoring, such citizen science practices resulted in lower consumption of contaminated foods.

While such examples demonstrate the power and potential of citizen science, there are inherent political complexities involved when citizens or nongovernmental organizations step in and claim expertise in areas typically reserved for state agencies and experts. Like those entities, citizen science has its own potential pitfalls……..  https://www.sapiens.org/culture/fukushima-citizen-science/

 

Fukushima Daiichi nuclear power plant’s deadly hazard – highly radioactive sandbags

Nuclear sandbags too hot to handle,  https://www.theaustralian.com.au/world/the-times/nuclear-sandbags-too-hot-to-handle/news-story/87b811443cb8e2881f55e17108872880 By RICHARD LLOYD PARRY, THE TIMES. APRIL 1, 2020  

Japanese engineers trying to dismantle the melted reactors at the Fukushima Daiichi nuclear power plant face a new hazard — radioactive sandbags so deadly that standing next to them for a few minutes could be fatal.

The sandbags were intended to make life easier for the teams dealing with the aftermath of the nuclear disaster in 2011 when three reactors melted after a tsunami destroyed their cooling systems. Twenty-six tonnes of the bags were placed in basements beneath two of the reactors to ­absorb radioactivity from waste water.

They were stuffed with zeolite, minerals that can absorb caesium. Nine years after the disaster, the submerged sandbags have sucked up so much radiation that they now represent a deadly danger themselves.

Samples of zeolite removed from the bags contain caesium, producing huge amounts of radiation, while the sandbags are giving off up to four sieverts of radiation an hour. Fifteen minutes of exposure to this could cause haemorrhaging. After an hour, half of those exposed would eventually die as a result. The maximum lifetime recommended dose of radiation for humans is less than half a sievert.

Tokyo Electric Power Co (Tepco), which operates the plant, had intended to remove the contaminated water by the end of 2020. The complication caused by the sand means it will take three years longer, the latest delay to the decommissioning.

Tepco managers have admitted that the technology needed to finish the job does not exist and they do not have a full idea of how it will be achieved. Their stated goal of decommissioning by 2051 may be impossible, they said.

One of the biggest problems is the 170 tonnes of irradiated water coming out of the plant every day, much of it natural ground water that flows through the earth ­towards the sea, picking up radiation on the way. Tepco pumps it out and stores it in huge storage tanks, filtered of some, but not all, of its contaminants — 1.17 million tonnes so far. In two years, the storage space will run out.

The government wants to pour the water away, insisting that the diluting effect of the ­Pacific will render the radiation harmless, but it is opposed by North and South Korea and the local fishing industry, whose reputation has been ruined by the disaster.

The clean-up of the Fukushima nuclear mess is not going to schedule – continual decommissioning delays

Japan’s 3/11 Recovery Stalled by Fukushima Decommissioning Delays Delays in dismantling the disaster-stricken nuclear power complex cast doubt on whether recovery goals will move forward according to schedule. The Diplomat  By Thisanka Siripala, March 13, 2020  Nine years after a quake-triggered tsunami sparked a triple meltdown at Fukushima Daiichi nuclear power plant, decontamination and decommissioning continues in northeastern Japan. The ultimate goal of removing all debris is expected to take anywhere between 30 to 40 years, but progress has been slower than originally planned. So far just one-fourth of decommission work has been completed, drawing attention to work that has not yet begun. The Fukushima decommissioning and decontamination draft has been amended five times. While changes published in December offered a specific time frame for the first time, the latest timetable for debris removal has been pushed back five years, citing the need for additional safety precautions. Previously, the process of removing spent fuel was scheduled from 2021 to 2024. But work on reactor two looks more likely to start in 2025 and last until 2027, followed by reactor one work commencing sometime between March 2028 and March 2029. …….. The next decommissioning stage sets out the removal of 4,471 spent fuel rods inside the cooling pools of reactors one to six. But the biggest obstacle is finding a way to locate and remove the molten nuclear fuel. With frequent delays, evacuees face a constant sense of uncertainty, tangled in a waiting game to see whether decommissioning work can be completed in 30 years. Reactor two is seen as the safest and easiest option to start full-scale debris removal since it suffered the least structural damage with only “some fuel” melting through the pressure vessel and accumulating at the bottom of the containment vessel.  But with no established method for debris retrieval, attempts to survey the location and distribution of molten nuclear fuel among the rubble requires a lengthy trial and error process. In mid-February 2019 an attempt to probe and collect samples from reactor two failed to find and lift the main nuclear fuel debris, instead lifting portions of pebble-like sediment with the lowest radiation readings from the surface. At this stage there is no way for TEPCO, the company that owns the Fukushima Daiichi plant, to determine where fuel debris lies among the rest of the metal debris. It’s estimated that reactor two alone contains 237 metric tons of debris while reactors one and three contain a combined 880 tons. The complexity of debris removal requires developing specialized technology that does not yet exist. Also plaguing decommissioning efforts is the battle over how to safely dispose of 1 million tons of contaminated water that were used to cool nuclear fuel. Currently, huge tanks on the premises store the polluted runoff, which could fill 400 Olympic swimming pools, but space is expected to run out by mid-2022. On average 170 tons of contaminated water is produced to cool fuel in nuclear reactors. Without constant cooling, nuclear fuel risks melting from its own heat in a process called decay heat. With two years needed to prepare a disposal method, time is running out for a final decision. Government proposals to slowly release contaminated water into the ocean has sparked fierce backlash from locals and the agriculture and fishing industries, who argue traces of radioactive materials such as tritium still found in “treated” water could further harm a region still struggling to restore its international reputation…….. To make matters worse, decommissioning operations have been temporarily suspended due to the spread of coronavirus. Tepco was forced to cancel on-site inspections of reactor one scheduled during March, which would have brought together some 1,800 experts and members of parliament, as well as local residents and student groups. https://thediplomat.com/2020/03/japans-3-11-recovery-stalled-by-fukushima-decommissioning-delays/

Analysis of decontamination of irradiated soil of Fukushima area

Fukushima: Lessons learned from an extraordinary case of soil decontamination  https://www.sciencedaily.com/releases/2019/12/191212081926.htm

Source:

European Geosciences Union

Summary:

Following the accident at the Fukushima nuclear power plant in March 2011, the Japanese authorities decided to carry out major decontamination works in the affected area, which covers more than 9,000 km2. On Dec. 12, 2019, with most of this work having been completed, researchers provided an overview of the decontamination strategies used and their effectiveness.

On December 12, 2019, with most of this work having been completed, the scientific journal SOIL of the European Geosciences Union (EGU) is publishing a synthesis of approximately sixty scientific publications that together provide an overview of the decontamination strategies used and their effectiveness, with a focus on radiocesium. This work is the result of an international collaboration led by Olivier Evrard, researcher at the Laboratoire des Sciences du Climat et de l’Environnement [Laboratory of Climate and Environmental Sciences] (LSCE — CEA/CNRS/UVSQ, Université Paris Saclay).

Soil decontamination, which began in 2013 following the accident at the Fukushima Dai-ichi nuclear power plant, has now been nearly completed in the priority areas identified1. Indeed, areas that are difficult to access have not yet been decontaminated, such as the municipalities located in the immediate vicinity of the nuclear power plant. Olivier Evrard, a researcher at the Laboratory of Climate and Environmental Sciences and coordinator of the study (CEA/CNRS/UVSQ), in collaboration with Patrick Laceby of Alberta Environment and Parks (Canada) and Atsushi Nakao of Kyoto Prefecture University (Japan), compiled the results of approximately sixty scientific studies published on the topic.

This synthesis focuses mainly on the fate of radioactive cesium in the environment because this radioisotope was emitted in large quantities during the accident, contaminating an area of more than 9,000 km2. In addition, since one of the cesium isotopes (137Cs) has a half-life of 30 years, it constitutes the highest risk to the local population in the medium and long term, as it can be estimated that in the absence of decontamination it will remain in the environment for around three centuries.

“The feedback on decontamination processes following the Fukushima nuclear accident is unprecedented,” according to Olivier Evrard, “because it is the first time that such a major clean-up effort has been made following a nuclear accident. The Fukushima accident gives us valuable insights into the effectiveness of decontamination techniques, particularly for removing cesium from the environment.”

This analysis provides new scientific lessons on decontamination strategies and techniques implemented in the municipalities affected by the radioactive fallout from the Fukushima accident. This synthesis indicates that removing the surface layer of the soil to a thickness of 5 cm, the main method used by the Japanese authorities to clean up cultivated land, has reduced cesium concentrations by about 80% in treated areas. Nevertheless, the removal of the uppermost part of the topsoil, which has proved effective in treating cultivated land, has cost the Japanese state about €24 billion. This technique generates a significant amount of waste, which is difficult to treat, to transport and to store for several decades in the vicinity of the power plant, a step that is necessary before it is shipped to final disposal sites located outside Fukushima prefecture by 2050. By early 2019, Fukushima’s decontamination efforts had generated about 20 million cubic metres of waste.

Decontamination activities have mainly targeted agricultural landscapes and residential areas. The review points out that the forests have not been cleaned up — because of the difficulty and very high costs that these operations2 would represent — as they cover 75% of the surface area located within the radioactive fallout zone. These forests constitute a potential long-term reservoir of radiocesium, which can be redistributed across landscapes as a result of soil erosion, landslides and floods, particularly during typhoons that can affect the region between July and October. Atsushi Nakao, co-author of the publication, stresses the importance of continuing to monitor the transfer of radioactive contamination at the scale of coastal watersheds that drain the most contaminated part of the radioactive fallout zone. This monitoring will help scientists understand the fate of residual radiocesium in the environment in order to detect possible recontamination of the remediated areas due to flooding or intense erosion events in the forests.

The analysis recommends further research on:

• the issues associated with the recultivation of decontaminated agricultural land3,
• the monitoring of the contribution of radioactive contamination from forests to the rivers that flow across the region,
• and the return of inhabitants and their reappropriation of the territory after evacuation and decontamination.

This research will be the subject of a Franco-Japanese and multidisciplinary international research project, MITATE (Irradiation Measurement Human Tolerance viA Environmental Tolerance), led by the CNRS in collaboration with various French (including the CEA) and Japanese organizations, which will start on January 1, 2020 for an initial period of 5 years.

Complementary approaches

This research is complementary to the project to develop bio- and eco-technological methods for the rational remediation of effluents and soils, in support of a post-accident agricultural rehabilitation strategy (DEMETERRES), led by the CEA, and conducted in partnership with INRA and CIRAD Montpellier.

Decontamination techniques

• In cultivated areas within the special decontamination zone, the surface layer of the soil was removed to a depth of 5 cm and replaced with a new “soil” made of crushed granite available locally. In areas further from the plant, substances known to fix or substitute for radiocesium (potassium fertilizers, zeolite powders) have been applied to the soil.
• As far as woodland areas are concerned, only those that were within 20 metres of the houses were treated (cutting branches and collecting litter).
• Residential areas were also cleaned (ditch cleaning, roof and gutter cleaning, etc.), and (vegetable) gardens were treated as cultivated areas.

1 In Fukushima prefecture and the surrounding prefectures, the decision to decontaminate the landscapes affected by the radioactive fallout was made in November 2011 for 11 districts that were evacuated after the accident (special decontamination zone — SDZ — 1,117 km2) and for 40 districts affected by lower, but still significant levels of radioactivity and that had not been evacuated in 2011 (areas of intensive monitoring of the contamination — ICA, 7836 km2). 2 128 billion euros according to one of the studies appearing in the review to be published on 12 December 2019 in SOIL. 3 Relating to soil fertility and the transfer of radiocesium from the soil to plants, for example.

The study was conducted by Olivier Evrard (Laboratoire des Sciences du Climat et de l’Environnement (LSCE/IPSL), Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay), J. Patrick Laceby (Environmental Monitoring and Science Division (EMSD), Alberta Environment and Parks (AEP)), and Atsushi Nakao (Graduate School of Life and Environmental Sciences, Kyoto Prefectural University).

A Govt panel to decide on dumping Fukushima waste water

Panel deciding whether to dump radioactive water from Fukushima into the ocean https://www.seafoodsource.com/news/environment-sustainability/panel-deciding-whether-to-dump-radioactive-water-from-fukushima-into-the-ocean By Chris Loew October 30, 2019 

The Japanese government may allow Tokyo Electric Power Company (TEPCO) to dump more than 250 million gallons of contaminated water accumulated in tanks around its Fukushima nuclear power plants into the ocean.

Environment Minister Yoshiaki Harada commented in September that he supports the plan, as it may be the only solution for the wastewater. An expert panel is now studying the options, and its recommendation is likely to become policy.

The contaminated water was used to cool the superheated fuel rods in the Fukushima Daiishi facility prior to and during the nuclear meltdown that occurred as a result of the Tōhoku earthquake and tsunami in March 2011. The water has already been treated by multiple facilities, including a multi-nuclide removal facility (an advanced liquid processing system, or “ALPS”), which removed most of the radioactive materials, including cesium and strontium, but not tritium. Tritium is difficult to separate from water, because it closely resembles hydrogen, which is a natural component of water.

Many methods, both practically tried and theoretical, do exist for separation and removal of tritium, and they were assessed in a report presented by the International Research Institute for Nuclear Decommissioning in 2013.  But all of them had the drawback of requiring a large amount of energy and equipment. Also, performance is poor for the low concentrations in the water at Fukushima Daiichi.

Last year, a team of researchers from Kindai University and private companies in western Japan developed an aluminum filter with holes of five nanometers or less in diameter. Steam of water containing tritium can be stopped, while that of water can pass. However, another issue is that 400 cubic meters of groundwater flowing into the basements of the buildings every day needs to be pumped and treated, necessitating treatment on a very large scale. This may not be justified when considering the actual danger of release to the ocean, according to the report.

Before the accident, tritium in cooling water was thinned with circulated sea water so that the allowable concentration might not be exceeded, and the diluted tritium was routinely released into the sea. Releasing the water at a rate that would allow it to be well diluted may be the best option, the report said.

While tritium has a radioactive half-life of 12.3 years, its biological half-life in the human body is only 10 days, and in fish it is less than two days. This is because tritium easily bonds to water, replacing the hydrogen atom. So as we drink and expel water, the tritium is carried away rather than accumulating in tissues. While some radioactive materials become concentrated as they move up the food chain, tritium is diluted.

The main danger of the policy is not actual harm, but rather public perceptions about the safety of seafood from Fukushima and its neighboring prefectures. Countries that have been gradually relaxing restrictions on imports of Japanese seafood may be forced by public fears to take a wait-and-see approach before further easing—a setback to local seafood firms, which have waited for years to return to their pre-disaster export figures.