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Dissolution of radioactive, cesium-rich microparticles released from the Fukushima Daiichi Nuclear Power Plant in simulated lung fluid, pure-water, and seawater

We report chemical durability of Cs-rich microparticle from Fukushima Daiichi.
The dissolution rate was estimated for various solution composition.
Cs-rich microparticles can remain in lung and environments for several decades.

1-s2.0-S0045653519311701-fx1.jpg

October, 2019

Abstract

To understand the chemical durability of highly radioactive cesium-rich microparticles (CsMPs) released from the Fukushima Daiichi Nuclear Power Plant in March 2011, we have, for the first time, performed systematic dissolution experiments with CsMPs isolated from Fukushima soils (one sample with 108 Bq and one sample with 57.8 Bq of 137Cs) using three types of solutions: simulated lung fluid, ultrapure water, and artificial sea water, at 25 and 37 °C for 1–63 days.

The 137Cs was released rapidly within three days and then steady-state dissolution was achieved for each solution type. The steady-state 137Cs release rate at 25 °C was determined to be 4.7 × 103, 1.3 × 103, and 1. 3 × 103 Bq·m−2 s−1 for simulated lung fluid, ultrapure water, and artificial sea water, respectively.

This indicates that the simulated lung fluid promotes the dissolution of CsMPs. The dissolution of CsMPs is similar to that of Si-based glass and is affected by the surface moisture conditions.

In addition, the Cs release from the CsMPs is constrained by the rate-limiting dissolution of silicate matrix.

Based on our results, CsMPs with ∼2 Bq, which can be potentially inhaled and deposited in the alveolar region, are completely dissolved after >35 years. Further, CsMPs could remain in the environment for several decades; as such, CsMPs are important factors contributing to the long-term impacts of radioactive Cs in the environment.

 

https://www.sciencedirect.com/science/article/pii/S0045653519311701?via%3Dihub&sfns=mo&fbclid=IwAR0tbULuzIFwPg-RLoasHtJGKV10yokXY4Nt0YPhuff6PE3lD-_XCCqgRn0

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November 4, 2019 Posted by | fukushima 2019 | , , | Leave a comment

Sports bodies need to make own assessments of Fukushima: Greenpeace nuclear specialist

“The first thing is … don’t trust the Japanese government, educate yourself. If you’re an organizing body, get independent verification and independent information about what the relative radiation levels are, what the risks are,” Burnie said.”
Nuclear specialist warns of unknown long-term health, environmental risks from Japan’s radioactive water disposal plan
20190821000626_0.jpg
Shaun Burnie, senior nuclear specialist with Greenpeace Germany, speaks about Tokyo’s plan to discharge a massive amount of radioactive water into the Pacific Ocean during an interview with The Korea Herald at Greenpeace Seoul’s office in central Seoul last week. (Greenpeace Seoul)
Aug 21, 2019
With less than a year to go until the Tokyo 2020 Summer Olympics, concerns are growing over the safety of the baseball and softball venues in disaster-hit Fukushima.
 
Seeking to break away from Japan’s association with high levels of radioactivity, the Abe government has branded the 2020 Olympics the “Recovery Games.”
 
But health and environmental risks from high levels of radiation persist in parts of Fukushima after the 2011 nuclear meltdown.
 
According to Shaun Burnie, a senior nuclear specialist with Greenpeace Germany, those visiting Fukushima for the Summer Games next year should take a proactive approach to educating themselves on which areas of Fukushima are affected by radiation and on the impact of exposure to radiation.
 
“In terms of safety, there are certain areas of Fukushima where we would certainly not advise athletes or spectators to spend any time. Those are areas particularly close to the Fukushima Dai-ichi plant, including where the torch processions will be taking place,” Burnie said in an interview with The Korea Herald at Greenpeace Seoul’s office in central Seoul last week.
 
“They are areas that are not safe for people to live. If you visit, you need to follow a radiation protocol. It is a bizarre situation that you are having Olympic events where people are concerned about radiation,” he added.
 
While noting that not all parts of Fukushima should be off limits, Burnie said athletes and sports bodies need to seek independent assessments on Fukushima, rather than relying on information provided by the Japanese government.
 
“It’s dangerous to just dismiss the whole of Fukushima as a radioactive disaster zone. It’s much more complex than that. The first thing is … don’t trust the Japanese government, educate yourself. If you’re an organizing body, get independent verification and independent information about what the relative radiation levels are, what the risks are,” Burnie said.
 
As the senior nuclear specialist with Greenpeace Germany, Burnie has followed the Japanese government’s handling of the tsunami and earthquake in March 2011 that resulted in the meltdown of three nuclear reactors at the Fukushima Dai-ichi power plant.
 
In a report published in January, Burnie alleged that Tokyo plans to dispose of some 1 million metric tons of contaminated water by discharging it into the Pacific Ocean after the Summer Olympics.
 
If Japan follows through with the move, radioactive water is expected to be present in Korea’s East Sea a year later.
 
“For the past five years we’ve been accessing the process, the discussions, the documents submitted by Tepco (Tokyo Electric Power Company) … we were reviewing some of Tepco’s data (last year) and we looked at it and went ‘there is something wrong here with Tepco’s processing,’” Burnie said.
 
“It became very clear there has been bad decisions made, not really surprising, by Tepco, by the (Japanese) government over the last five or six years and how to manage the water crisis.”
 
Last year Tepco acknowledged its Advanced Liquid Processing System, or ALPS, had failed to purify contaminated water stored in tanks at the Dai-ichi power plant.
 
A committee under Japan’s Ministry of Economy in 2016 put together five scenarios for the Japanese government to deal with the massive volume of pollutants stored at the Fukushima No. 1 plant.
 
The amount of water stored at the plant is to reach its full capacity of 1.3 million tons by the end of 2020, with about 170 tons accumulating daily.
 
According to Burnie, Tokyo has chosen to discharge the radioactive water instead of acting on any of the other four suggestions because “it is the most cheap and fast.”
 
Besides increased levels of radioactive cesium found in Fukushima and in the East Sea, Burnie warned of “cesium-rich micro particles” extremely small in size and inhaled through breathing.
 
Cesium is one of the largest sources of radioactivity from the 2011 disaster and has a half-life of 30 years.
 
“There is evidence from samples … some scientific literature has published the results and they found concentrations of these particles in areas 20-30 kilometers from the plant. … The problem is these particles can be inhaled. Then some of them lodge inside your lung at which point you are getting an internal dose, a very focused, very localized, relatively high-exposure dose to individual cells,” Burnie said.
 
“That’s a real problem because there is very little known about how cesium in that form will affect your long-term health. … Again, the people most at risk are those returning to live in areas of Fukushima affected by these particles. But the Japanese government has not taken into account in any of its assessments what those risks are,” he added.
 
Stressing that the risks of exposure to radiation should not be exaggerated, Burnie noted there is no safe level of radiation exposure and the long-term effects are unknown.
 
“The effects you will only see over decades. It won’t be instant, it’s not an acute radiation exposure, it’s low-level radiation,” Burnie said.
 
“The country that will be next impacted will be Korea, because it’s the geographically closest. … There is no safe threshold for radiation exposure. … Why should you be exposed when there is a clear alternative, which is you store?”
http://www.koreaherald.com/view.php?ud=20190821000749

August 22, 2019 Posted by | fukushima 2019 | , , , , , | Leave a comment

Tokyo’s Fukushima cesium-enriched microparticle (CsMP) update

CsMP-01-2.jpgSecondary electron images from Utsunomiya et al. 2019, of CsMPs discovered in atmospheric particles trapped on a Tokyo air filter from March 15, 2011, with major constituent elements displayed. 

 

August 17th, 2019

An interesting paper  was recently published by a team headed by Dr. Satoshi Utsunomiya of Kyushu University on the subject of Fukushima-derived cesium-enriched microparticles (CsMPs). As many readers will know, several researchers have located and analyzed these microparticles, in which the cesium is often bonded within glass-like silicates and therefore generally significantly less soluble than other Cs chemical species in water, though technically not actually “insoluble.” After an accident like Fukushima, it is much more common to find cesium in water-soluble compounds like cesium hydroxide (CsOH), and predictions about how quickly the cesium will be dispersed through the environment, in soil, in watersheds, taken up by plants and animals, etc, are based primarily on this assumption. The discovery of sparingly-soluble Fukushima-derived cesium microparticles, first documented by Adachi et al in 2013, and since then confirmed by many others, has raised a number of questions. How abundant are they? Does their presence increase health risk to humans? How much do they reveal about the process of the accident itself? From the standpoint of researchers the microparticles are very intriguing.

Utsunomiya et al.’s paper is titled “Caesium fallout in Tokyo on 15th March, 2011 is dominated by highly radioactive, caesium-rich microparticles,” and as noted in a recent Scientific American article, it was originally accepted for publication in 2017 by Scientific Reports journal. Weeks before publication, however, Tokyo Metropolitan Industrial Technology Research Institute (TIRI), operated by the Tokyo Metropolitan Government, raised objections with Scientific Reports. However no questions about the quality of the science or the validity of the paper’s findings appear to have been brought forward. This in itself was highly irregular. Two years elapsed without resolution, and in March of this year Scientific Reports took the highly unusual step of withdrawing its offer to publish the paper, despite the lack of confirmed evidence that would warrant it. Utsunomiya and several co-authors decided that the best course of action was to place the study in the public domain by publishing it via arXiv, a highly respected pre-print website. The paper is now open and free to download. 

This study makes a valuable contribution to the body of scientific literature regarding the consequences of the Fukushima disaster in general and CsMPs in particular. I think it was a mistake for Scientific Reports not to publish it two years ago, especially considering the rapid pace of research into these particles and the tremendous interest in them. To summarize the findings briefly, the researchers analyzed air filter samples from March 15, 2011, in Setagaya, Tokyo, when the radioactive plume from Fukushima caused a noticeable peak in airborne radioactivity in the city. The researchers used radiographic imaging (placing the filters on a photographic plate) to identify any highly radioactive spots. Using these images as a guide they were able to isolate seven CsMPs, which they subjected to atomic-scale analysis using high-resolution electron microscopy (HRTEM) to identify their nano-scale structure and chemical composition. Based on these detailed measurements and quantitative analysis, the researchers concluded that 80-89% of the total cesium fallout in Tokyo that day was in the form of highly radioactive microparticles. The second half of the paper is devoted to estimates of how long such particles might be retained in the human lungs if inhaled, based on previous studies that reported the effects of inhalation of non-radioactive atmospheric particles, and some possible physical consequences. The paper is valuable for the quantitative analysis of the Tokyo particles alone, since it is one of few studies that deal with the issue for Tokyo specifically. Research into possible health consequences of the particles, meanwhile, has gained momentum while the paper remained unpublished, using approaches such as stochastic biokinetics, and DNA damage studies.  In a recent paper, Utsunomiya and colleagues produced estimates of the rate of dissolution of the particles inside the human lung, in pure water, and in seawater. A working group at the Japan Health Physics Society has also devoted attention to the issue, noting the need for further study of the risk from intake of these particles, particularly to the lung.  Likewise, others have been studying the particles to learn about the accident progression and possible consequences for decommissioning.

Why did Tokyo Metropolitan Industrial Technology Research Institute object to the paper’s publication? When we first heard that publication of the paper was being held up by Tokyo Metropolitan Government, we thought politically-motivated suppression was a likely explanation. Since then the public has learned that the actual complaint given to Scientific Reports stems from a chain of custody issue of the original air filter samples. We don’t want to speculate further about Tokyo’s motivation, because we have seen no direct evidence yet of political suppression in this case. But based on past occurrences with other government institutions, we would find it plausible. We will let readers know if TIRI responds to our inquiries.

We spoke with Dr. Utsunomiya and co-author Dr. Rodney Ewing recently. I was aware of their co-authorship of several strong papers on CsMPs, including Utsunomiya’s plenary talk at the Goldschmidt Conference in Yokohama in 2016, which I attended. I asked how this new arXiv paper fits in with their other papers, and where they think this research is heading next:

Satoshi Utsunomiya:

Thank you for asking. The Tokyo paper was actually our first paper regarding CsMPs. As I mentioned, the paper was accepted two years ago. There were no previous papers of ours on CsMPs that time. Currently we are working on several topics on CsMPs. I cannot reveal the content yet, as we are thinking about a press release for the next paper. But I think it is important to continue this kind of research, providing some insights for decommissioning at Fukushima Daiichi Nuclear Power Plant.

Azby Brown:

I didn’t realize that this was your first paper on the subject.  How does it relate to the one presented at the Goldschmidt Conference in Yokohama in 2016? “Cesium-Rich Micro-Particles Unveil the Explosive Events in the Fukushima Daiichi Nuclear Power Plant.” Didn’t that paper receive a prize?

SU:

My talk at Goldschmidt briefly covered the story described in the two papers that were accepted for publication at the same time. One was published in Scientific Reports. The other one was not published. There was no prize. It was a plenary talk.

AB:

I see. I recall that it received a lot of attention. Now it makes more sense to me.

Can you tell me a little bit about the specific characteristics and focus of your research, and how it differs from papers like Adachi 2013, Abe 2014, etc? Generally speaking, that is. I’d like to help people understand the different aspects of the field.

SU:

Adachi reported the discovery of CsMPs. Abe demonstrated X-ray absorption analysis on the CsMPs. We focused on the nanotexture inside CsMPs. We are particularly interested in the detailed evidence remaining within the microparticle, which can provide useful information on the development of the chemical reactions during the meltdowns, because it is still difficult to directly analyze the materials inside the reactors. We, for the first time, succeeded in performing isotopic analysis on individual CsMPs. More specifically, the occurrence of uranium can directly tell the story of how the fuel melted. Our research has two directions: one is to understand the environmental impact of CsMPs, and the other is to provide useful information on the debris properties to help decommissioning at FDNPP. We are also interested in the implications for health.

AB:

Can you tell me a little bit about your working relationship? Satoshi went to the US to work in your lab, right Rod? When was that, and what were you working on?

Rod Ewing:

Satoshi and I have known each other since 2000, when he joined my research group as a post-doctoral fellow at the University of Michigan. He was a member of the research group until 2007. We collaborated on a wide range of topics that had to do with radioactive materials, such as the transport of plutonium at the Mayak site in Russia to the identification of uranium phases within C60 cages, so called buckyballs, that were formed and released from coal power plants. Once Satoshi returned to Japan to take his position at Kyushu University, we continued to collaborate, particularly on topics related to Fukushima Daiichi.

AB:

How did you both get interested in CsMPs?

RE:

Once discovered, CsMPs were clearly of high interest. They had not been noted in earlier reactor accidents. Satoshi is a master with the transmission electron microscope – exactly the tool/technique needed to study these particles.

AB:

For people who aren’t familiar with what’s involved in a research experiment like yours, can you describe the overall process? What were the technical challenges?

RE:

I would just emphasize that it is very difficult to find and characterize these particles. Considering the full literature and efforts by others as well as our team – the results are impressive. It is rare to have both the TEM characterization and the isotopic data.

SU:

As Rod mentioned, it is difficult to obtain both TEM and isotopic data from a few micron-sized spots. The isolation of CsMPs from soils is a time consuming process. But to date, many scientists have found and isolated CsMPs. The important thing is what information we can obtain from the analysis of CsMPs. We have been taking various approaches to elucidate the properties, environmental impact, and the role in releasing fissile actinides to the environment.    

As described above, many papers examining various aspects of Fukushima-derived cesium microparticles have been published since they were first identified in 2013. Even so, important aspects remain only partially documented and understood to date. Below is a partial list of relevant publications.

Papers mentioned in this article:

Caesium fallout in Tokyo on 15th March, 2011 is dominated by highly radioactive, caesium-rich microparticles

Utsunomiya, et al., 2019

https://arxiv.org/abs/1906.00212

—————————————————————–

Emission of spherical cesium-bearing particles from an early stage of the Fukushima nuclear accident

Adachi et al., 2013

http://www.nature.com/articles/srep02554

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Detection of Uranium and Chemical State Analysis of Individual Radioactive Microparticles Emitted from the Fukushima Nuclear Accident Using Multiple Synchrotron Radiation X-ray Analyses

Abe et al., 2014

http://pubs.acs.org/doi/abs/10.1021/ac501998d

—————————————————————–

Dissolution of radioactive, cesium-rich microparticles released from the Fukushima Daiichi Nuclear Power Plant in simulated lung fluid, pure-water, and seawater

Suetake et al., 2019

https://doi.org/10.1016/j.chemosphere.2019.05.248

—————————————————————–

Development of a stochastic biokinetic method and its application to internal dose estimation for insoluble cesium-bearing particles

Manabe & Matsumoto, 2019

https://doi.org/10.1080/00223131.2018.1523756

—————————————————————–

DNA damage induction during localized chronic exposure to an insoluble radioactive microparticle

Matsuya et al., 2019

https://doi.org/10.1038/s41598-019-46874-6

—————————————————————–

Provenance of uranium particulate contained within Fukushima Daiichi Nuclear Power Plant Unit 1 ejecta material

Martin et al., 2019

https://www.nature.com/articles/s41467-019-10937-z

—————————————————————–

Internal doses from radionuclides and their health effects following the Fukushima accident

Ishikawa et al., 2018

https://iopscience.iop.org/article/10.1088/1361-6498/aadb4c

 

Related papers (by year of publication):

Characteristics Of Spherical Cs-Bearing Particles Collected During The Early Stage Of FDNPP Accident

Igarashi et al., 2014

http://www-pub.iaea.org/iaeameetings/cn224p/Session3/Igarashi.pdf

—————————————————————–

Radioactive Cs in the severely contaminated soils near the Fukushima Daiichi nuclear power plant

Kaneko et al., 2015

https://www.frontiersin.org/articles/10.3389/fenrg.2015.00037

—————————————————————–

First successful isolation of radioactive particles from soil near the Fukushima Daiichi Nuclear Power Plant

Satou et al., 2016

http://www.sciencedirect.com/science/article/pii/S2213305416300340

—————————————————————–

Internal structure of cesium-bearing radioactive microparticles released from Fukushima nuclear power plant

Yamaguchi et al., 2016

http://www.nature.com/articles/srep20548

—————————————————————–

Three-Year Retention Of Radioactive Caesium In The Body Of Tepco Workers Involved In The Fukushima Daiichi Nuclear Power Station Accident

Nakano et al., 2016

http://rpd.oxfordjournals.org/content/early/2016/03/14/rpd.ncw036

—————————————————————–

Monte Carlo Evaluation of Internal Dose and Distribution Imaging Due to Insoluble Radioactive Cs-Bearing Particles of Water Deposited Inside Lungs via Pulmonary Inhalation Using PHITS Code Combined with Voxel Phantom Data

Sakama, M. et al., 2016

http://scholar.google.com/scholar_lookup?&title=Radiological%20Issues%20for%20Fukushima%E2%80%99s%20Revitalized%20Future&pages=209-220&publication_year=2016&author=Sakama%2CMinoru&author=Takeda%2CShinsaku&author=Matsumoto%2CErika&author=Harukuni%2CTomoki&author=Ikushima%2CHitoshi&author=Satou%2CYukihiko&author=Sueki%2CKeisuke

—————————————————————–

Radioactively-hot particles detected in dusts and soils from Northern Japan by combination of gamma spectrometry, autoradiography, and SEM/EDS analysis and implications in radiation risk assessment

Kaltofen & Gundersen, 2017

https://www.sciencedirect.com/science/article/pii/S0048969717317953?via%3Dihub

—————————————————————–

Caesium-rich micro-particles: A window into the meltdown events at the Fukushima Daiichi Nuclear Power Plant

Furuki et al., 2017

https://www.nature.com/articles/srep42731

—————————————————————–

Isotopic signature and nano-texture of cesium-rich micro-particles: Release of uranium and fission products from the Fukushima Daiichi Nuclear Power Plant

Imoto et al., 2017

—————————————————————–

Uranium dioxides and debris fragments released to the environment with cesium-rich microparticles from the Fukushima Daiichi Nuclear Power Plant

Ochiai et al., 2018

https://pubs.acs.org/doi/abs/10.1021/acs.est.7b06309

—————————————————————–

Novel method of quantifying radioactive cesium-rich microparticles (CsMPs) in the environment from the Fukushima Daiichi nuclear power plant

Ikehara et al., 2018

https://pubs.acs.org/doi/full/10.1021/acs.est.7b06693

—————————————————————–

Formation of radioactive cesium microparticles originating from the Fukushima Daiichi Nuclear Power Plant accident: characteristics and perspectives

Ohnuki, Satou, and Utsunomiya, 2019

https://www.tandfonline.com/doi/abs/10.1080/00223131.2019.1595767

https://blog.safecast.org/2019/08/fukushima-cesium-enriched-microparticle-csmp-update/

August 22, 2019 Posted by | fukushima 2019 | , , , , | Leave a comment

Fukushima unrecognized threat of radioactive microparticles

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Fukushima Microparticles, An Unrecognized Threat

In the years since the initial disaster there have been disparities between the official radiation exposure estimates and the subsequent health problems in Japan. In some cases the estimates were based on faulty or limited early data. Where a better understanding of the exposure levels is known there still remained an anomaly in some of the health problems vs. the exposure dose. Rapid onset cancers also caused concern. The missing piece of the puzzle may be insoluble microparticles from the damaged reactors.
 
What are microparticles ?
These microscopic bits of fuel and other materials from the reactor meltdowns have been found around Japan since soon after the disaster. Citizens with hand held radiation meters first discovered them as highly radioactive fine black sands on roadsides and gutters. These substances eventually caught the attention of researchers who determined they are tiny fused particles of vaporized reactor fuel, meltdown byproducts, structural components of the reactors and sometimes concrete from the reactor containments. The Fukushima microparticles are similar to “fuel fleas” or “hot particles“. Hot particles or fuel fleas have been found at operating nuclear reactors that had damaged fuel assemblies. These fused particles found around Japan are different in that they are a byproduct of the reactor meltdowns.
The small size of these microparticles, smaller than 114 μm makes them an inhalation risk. Other studies have also confirmed the size is small enough to inhale. These microparticles have been found near Fukushima Daiichi, in the evacuation zone, outside of the evacuation zone and as far away as Tokyo.
 
How microparticles were created at Fukushima Daiichi
The heat of the meltdown processes reached temperatures high enough to cause the nuclear fuel and other materials to break down into small particles. The uranium in the fuel further oxidized and then volatilized once temperatures reached 1900K. As these materials broke down into nanoparticle sized components of the fuel melt process, this set up the conditions for them to condense.  As these materials cooled the fused microparticles were created. Newer studies call these microparticles “CsMPs” (Cesium bearing micro particles).  A 2018 study of how these microparticles were created gives a plain language explanation of the process. https://pubs.acs.org/doi/pdf/10.1021/acs.est.7b06309
“From these data, part of the process that the FDNPP fuels experienced during the meltdown can be summarized as the follows: Cooling waters vaporized, and the steam reacted with Zr and Fe forming their oxides after the loss of power to the cooling system. UO2, which is the main composition of fuels, partially oxidized and volatilized at greater than ∼1900 K. (9,10) The fuel assemblies melted unevenly with relatively less irradiated fuels being heated to a higher temperature as compared with the high burnup fuels and volatilized as evidenced by the 235U/238U isotopic ratio.(9) The fuel assembly collapsed and moved to the bottom of RPV. The temperature increased locally to at least greater than 2400 K based on the liquidus temperature of U−Zr oxides. Locally formed oxides melted to a heterogeneous composition, including a small amount of Fe oxides,(27) which then became a source of Fe−U single crystals and U−Zr-oxide eutectic phases. Specifically, euhedral magnetite nanocrystals encapsulated euhedral uraninite nanocrystals, which would have crystallized slowly at this stage. Liquid U−Zr-oxide nanodroplets were rapidly cooled and solidified to a cubic structure. When the molten fuels hit the concrete pedestal of the PCV, SiO gas was generated at the interfaces between the melted core and concrete and instantly condensed to form CsMPs.(5) The U−Zr-oxide nanoparticles or the magnetite nanocrystals subsequently formed aggregates with CsMPs. Finally, the reactor debris fragments were released to the environment along with CsMPs.”
The microparticles may have left the reactors through multiple processes including containment leaks,  containment venting operations, hydrogen explosions and the later reduction and addition of water in an attempt to control the molten fuel.
 
New study looks at how to quantify these substances
A new study found a useful way to quantify how much of the contamination in an area is due to microparticles (hot particles). By using autoradiography they were able to confirm the number of microparticles in a sample. Soil samples near Fukushima Daiichi ranged from 48–318 microparticles per gram.  The microparticles had high concentrations of radioactive cesiums, in the range of ∼1011 Bq/g. The study stresses the health concern that these microparticles pose due to cellular damage from the highly concentrated radiation level. The authors also mention the risk re-suspension of microparticles in the air poses to the public.
Not just cesiums
A separate study found strontium-90 in the Fukushima microparticles at a ratio similar to what has been found in contaminated soil samples. This study included the amount of hot particles (aka: microparticles) found in soil samples taken in the fallout zone in Fukushima north-west of the plant. They ranged from 0-18 microparticles per square meter of soil. This information confirms that strontium-90 is part of some of these fused microparticles. https://academic.oup.com/jrr/advance-article/doi/10.1093/jrr/rry063/5074550
An ongoing research project and paper by Marco Kaltofen documents these hot particles further. In the 2017 paper they found more than 300 such hot particles from Fukushima Daiichi in Japanese samples.  A hot particle was found in a vacuum cleaner bag from Nagoya, over 300 km from the disaster site. https://www.sciencedirect.com/science/article/pii/S0048969717317953?via%3Dihub
“300 individual radioactively-hot particles were identified in samples from Japan; composed of 1% or more of the elements cesium, americium, radium, polonium, thorium, tellurium, or strontium. Some particles reached specific activities in the MBq μg− 1 level and higher.”
The study found americium 241 in two house dust samples from Tokyo and in one from Sendai, 100 km north of the disaster site.  The sample set collected in 2016 showed a similar instance of highly radioactive hot particles compared to the 2011 samples. This appears to show that the threat from these reactor ejected hot particles has not gone away. A majority of the collected samples were from locations declared decontaminated by the national government.
The above graph is from the 2017 Kaltofen paper. These represent the highest readings for cesium found in their microparticle samples. The highest in the graph is Namie black sand. These black sand substances found around Fukushima prefecture and as far south as Tokyo were discovered to be largely made up of ejected reactor materials based on multiple studies.
The 2018 study we cited earlier in this report to explain the microparticle creation process also confirms some of these microparticles also contain radioactive isotopes of uranium. This further confirms the creation of some of these microparticles from the fuel itself. Uranium poses a particular concern due to the extremely long half lives involved.
 
How these act differently in the environment
In the case of the microparticles that contained Strontium 90, the isotope would normally move with water in the environment. Due to the insolubility of the microparticles, the strontium 90 stays in the top soils. Studies on microparticles predominantly carrying radioactive cesiums showed that the radioactive substances did not migrate through the environment as expected.
Microparticles were found in road gutters, sediment that collected in parking lots, below downspouts and similar places where sediments could concentrate. These initial discoveries hint at how the microparticles could migrate through the environment. The findings of the 2017 Kaltofen study indicate that microparticles can persist years later, even in places that were decontaminated. This may be due to the natural processes that have caused many areas to recontaminate after being cleaned up. There has been no effort to clean up forest areas in Japan. Doing so was found to be extremely difficult. The forest runoff may be one method of recontamination.
 
The risk to humans and animals
The subject of hot particles and the risk that they might pose to human or animal health has been controversial in recent years. Some studies found increased risks, others claimed a lesser risk from these substances. One study we reviewed may have discovered the nuances of when these substances are more damaging.
Most studies on hot particles aimed to determine if they were more damaging than that of a uniform radiation exposure to the same body part. A 1988 study by Hoffman et. al. found that hot particle damage varied by the radiation level of the particle, distance to nearby cells and the movement of the particle within the tissue. A high radiation particle might kill all the nearby cells but cause transformation in cells further away. Those dead cells near the hot particle would stimulate the transformed cells to reproduce faster to replace the dead cells. https://academic.oup.com/rpd/article-abstract/22/3/149/161256
A hot particle of moderate radiation would cause more transformations than cell death of nearby cells. High radiation hot particles that moved around in the organ, in this case the lung, would cause the most transformations. These acted like multiple moderate radiation hot particles transforming cells as they moved around. Those transformations are what can turn into cancers. This study’s findings appear to explain the results found in other studies where fewer cancers were found than they expected in certain groups.
A veteran who was exposed during US atomic testing had experience over 300 basal cell carcinomas. The study concluded that the skin cancers in atomic veterans could be induced by their radiation exposure. Continued exposure to ultraviolet radiation then promoted those cancers.
Other studies found damage in animal models. A study of hot particles on pig skin showed roughly half of the exposures caused small skin lesions. Two in the higher exposure group caused infections, one of these resulted in a systemic infection. https://inis.iaea.org/collection/NCLCollectionStore/_Public/28/061/28061202.pdf
A mouse study where hot particles were implanted into the skin found increased cancers of the skin. https://www.tandfonline.com/doi/abs/10.1080/09553009314550501
Workers at Fukushima Daiichi in the group with some of the highest radiation exposures were discovered to have these insoluble microparticles lodged in their lungs. When the workers radiation levels didn’t decrease as expected, further tests were done. Scans found the bulk of the worker’s body contamination was in their lungs. The lung contamination persisted on subsequent scans. The looming concern is that these microparticles in the lungs can not be ejected by the body.
 
Risks have been known for decades 
The US NRC issued an information notice related to a series of hot particle exposures at nuclear plants where workers were exposed beyond legal limits. https://www.nrc.gov/reading-rm/doc-collections/gen-comm/info-notices/1987/in87039.html
Damaged fuel was the source in all cases. Even improperly laundered protective clothing was found to be a risk factor. Contaminated clothing from one facility could make it through the laundry process with a hot particle undetected on bulk scans of finished laundry. This would then result in an exposure to a different worker at a different plant who donned the contaminated gear. The hot particles when in contact with skin can give a high dose rate. Plants with even small fuel assembly leaks saw significant increases in worker exposure levels.
“In addition to any increased risk of cancer, large doses to the skin from hot particles also may produce observable effects such as reddening, hardening, peeling, or ulceration of the skin immediately around the particle. “
These problems are thought to only occur in high dose exposures from hot particles. One worker in the review had an estimated 512 rem radiation exposure from a hot particle.  Workers at US nuclear power plants are subjected to strict screening programs when they exit or return to work. This increases the chance of detecting and removing a hot particle before it can do more damage. This also lessens the potential for one to leave the plant site. The general public exposed to a nuclear plant disaster does not receive this level of scrutiny.
 
How this risk may have played out in Fukushima
Soon after the reactor explosions ripped through Fukushima Daiichi, people in the region began complaining of nosebleeds and flu like symptoms. These eventually began being reported as far south as Chiba and Tokyo.  https://www.aljazeera.com/indepth/features/2011/08/201181665921711896.html
The government responded that these complaints were “hysteria” or people trying to scare others. These problems were so widespread and coming from diverse people it had seemed to be a significant sign in the events that unfolded.
On March 21, 2011 there was rain in Tokyo that may have washed out contamination still being ejected at the plant. Events at Daiichi between March 17-21 caused increased radiation releases.
In 2013 there was an unusual uptick in complaints about severe nosebleeds. This happened at the time typhoon Man-yi made landfall in Tokyo. The bulk of the people who responded to a survey by a foreign policy expert working in the office of a member of Japan’s Diet were from the Kanto region (Tokyo) where the typhoon made landfall.
Children in the Fukushima region that were found to have thyroid problems also complained of frequent nosebleeds and skin rashes.  People have described unusual ongoing health problems such as this woman in Minami Soma near Fukushima Daiichi who had odd rashes, a rapid loss of teeth etc.  Cattle housed 14 km from the disaster site have shown with white spots all over their hides, something previously seen after US nuclear tests. https://www.huffingtonpost.com/evaggelos-vallianatos/the-nuclear-meltdown-at-f_b_4209766.html
The USS Reagan was offshore of Fukushima Daiichi March 11 to 14th. Plume maps for iodine 131 (a gaseous release from the meltdowns) blew in the wind north and at times east out to sea during those dates. These same winds could have carried microparticles out to sea. A number of sailors on the Reagan and those working with the rescue helicopters have fallen ill. Eight have died since the disaster. This newer account of the events on the Reagan raise even more concerns about what happened to those trying to save people after the tsunami.
Namie Mayor, Tamotsu Baba resigned his office in June 2018 after a year of off and on hospitalization. He had been undergoing treatment for gastric cancer. He died a few weeks after resigning. His cancer may have predated the disaster, but in the last year his health drastically declined. Namie is in the area of some of the highest fallout from the disaster.
Fukushima plant manager Masao Yoshida died of esophageal cancer in 2013. TEPCO insisted his cancer was not related to the disaster due to the rapid onset. This is a common claim around cancers that could be tied to Fukushima, yet the number of cancers soon after the disaster has been hard to ignore.
As we neared completion of this report the labor ministry announced that the lung cancer death of a Fukushima Daiichi worker was tied to his work during the disaster. The worker was at the plant during the early months of the disaster and worked there until 2015. TEPCO didn’t give specifics of his work role, only mentioning he took radiation levels. TEPCO mentioned that the worker wore a “full face mask respirator” during his work. All of the workers at Daiichi wore the same after ordered to do so after meltdowns were underway. The worker was not among the highest exposure bracket so he may not have been receiving detailed health monitoring. Radiation exposure monitoring during the early months of the disaster was inconsistent and sometimes missed exposures. https://mainichi.jp/english/articles/20180905/p2a/00m/0na/004000c
 
What microparticles change about the disaster
Highly radioactive microparticles were released to the environment during the meltdowns, explosions and subsequent processes in units 1-3 at Fukushima Daiichi.
Microparticles have been found near the disaster site, in the evacuation zone, far outside of the evacuation zone and south into the Tokyo region. These substances persist in the environment and have been found in areas previously decontaminated.
These microparticles significantly change the exposure estimates for the general public. Individual exposures can not be accurately estimated by the use of generic environmental radiation levels as this does not account for the individual’s exposure to microparticles.
Microparticle exposure has multiple variables that create a unique level of risk to the exposed human or animal. They can in the right circumstances cause significant damage to nearby tissues, persist in the body, cause damage, initiate or promote a cancer.
Microparticle exposures may be the missing puzzle piece that explains a number of odd problems tied to the Fukushima disaster. Health problems that showed up soon after the disaster. Exposed populations with aggressive or sudden cancers and other serious health problems that can be created or exacerbated by radiation exposure.
Microparticles continue to pose a public health risk in some parts of Japan that experienced fallout and increased radiation levels due to the disaster.

September 10, 2018 Posted by | Fukushima 2018 | , , , | Leave a comment

Loss of radioactivity in radiocesium-bearing microparticles emitted from the Fukushima Dai-ichi nuclear power plant by heating

In this article, we learn that microscopic glass beads containing Cesium 137 “lose” their radioactivity when, mixed with other radioactive debris, they are burned up in incinerators.
The researchers are pleased to see that the ashes from these incinerators will be free of Caesium 137.
It should be pointed out that radioactivity never disappears like that instantaneously. In the best of cases this Cesium will be, one can dream, filtered in the chimneys of incinerators. Otherwise the incineration will have simply served to disperse the radioactive cesium from the microscopic beads in the form of aerosols.
It is unfortunate that scientists are not working in a free vacuum, but need for their career and for their researches the approval and the financing of governmental and corporate institutions. In this case, those 4 Japanese scientists, Taiga Okumura, Noriko Yamaguchi, Terumi Dohi, Kazuki Iijima & Toshihiro Kogure, just spinned this paper into a ‘scientific’ propaganda to justify the Japanese government backed-up incineration.…
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Abstract
Radiocesium-bearing microparticles (CsPs) substantially made of silicate glass are a novel form of radiocesium emitted from the broken containment vessel of Fukushima Dai-ichi nuclear power plant. CsPs have a potential risk of internal radiation exposure caused by inhalation. Radiation-contaminated waste including CsPs is being burned in incinerators; therefore, this study has investigated the responses of CsPs to heating in air. The radioactivity of CsPs gradually decreased from 600 °C and was almost lost when the temperature reached 1000 °C. The size and spherical morphology of CsPs were almost unchanged after heating, but cesium including radiocesium, potassium and chlorine were lost, probably diffused away from the CsPs. Iron, zinc and tin originally dissolved in the glass matrix were crystallized to oxide nanoparticles inside the CsPs. When the CsPs were heated together with weathered granitic soil that is common in Fukushima, the radiocesium released from CsPs was sorbed by the surrounding soil. From these results, it is expected that the radioactivity of CsPs will be lost when radiation-contaminated waste including CsPs is burned in incinerators.
https://www.nature.com/articles/s41598-018-28087-5

July 19, 2018 Posted by | Fukushima 2018 | , , , , | Leave a comment

Uranium Dioxides and Debris Fragments Released to the Environment with Cesium-Rich Microparticles from the Fukushima Daiichi Nuclear Power Plant

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January 29, 2018
Trace U was released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) during the meltdowns, but the speciation of the released components of the nuclear fuel remains unknown.
 
We report, for the first time, the atomic-scale characteristics of nanofragments of the nuclear fuels that were released from the FDNPP into the environment.
 
Nanofragments of an intrinsic U-phase were discovered to be closely associated with radioactive cesium-rich microparticles (CsMPs) in paddy soils collected ∼4 km from the FDNPP. The nanoscale fuel fragments were either encapsulated by or attached to CsMPs and occurred in two different forms: (i) UO2+X nanocrystals of ∼70 nm size, which are embedded into magnetite associated with Tc and Mo on the surface and (ii) Isometric (U,Zr)O2+X nanocrystals of ∼200 nm size, with the U/(U+Zr) molar ratio ranging from 0.14 to 0.91, with intrinsic pores (∼6 nm), indicating the entrapment of vapors or fission-product gases during crystallization.
 
These results document the heterogeneous physical and chemical properties of debris at the nanoscale, which is a mixture of melted fuel and reactor materials, reflecting the complex thermal processes within the FDNPP reactor during meltdown.
 
Still CsMPs are an important medium for the transport of debris fragments into the environment in a respirable form.
 

March 6, 2018 Posted by | Fukushima 2018 | , , , , | Leave a comment

Fukushima Disaster Released Uranium, Unexpected Particles

gate of difficult to return zone march 11 2014.pngThe gate of “Difficult-to-return zone” in Fukushima on March 11, 2014

The Fukushima Daiichi nuclear disaster was believed to have only resulted in the release of gases. But seven years after one of history’s few radioactive disasters, scientists have found that uranium and other solid microparticles were also released into the surrounding parts of Japan.

The particles are a fraction of the width of a human hair – which means they could be inhaled, according to the study in the journal Environmental Science Technology.

“Our research strongly suggests there is a need for further detailed investigation on Fukushima fuel debris, inside, and potentially outside the nuclear exclusion zone,” said Gareth Law, one of the authors, of the University of Manchester.

The debris, which included uranium, caesium and technetium, was discovered in the nuclear exclusion zone, several kilometers from the epicenter of the disaster at the Fukushima plant.

Two locations were paddy oils, and an abandoned aquaculture center.

Uranium itself has a half-life of 4.5 billion years.

The previously acknowledged radioactive materials were cesium and iodine, both taking the form of volatile gases. Other gases were released, as well.

But the new information about particles potentially means a longer, bigger cleanup, according to the latest study, led by Satoshi Utsunomiya of Kyushu University.

“Having better knowledge of the released microparticles is also vitally important as it provides much needed data on the status of the melted nuclear fuels in the damaged reactors,” said Utsunomiya. “This will provide extremely useful information for (The Tokyo Electric Power Company’s) decommissioning strategy.”

The March 2011 Fukushima disaster was triggered by a massive 9.0-scale earthquake, then a 15-foot tsunami. The Daiichi plant lost power, which prevented normal cooling operations – and caused the meltdown of all three cores at the plant within a few days. The removal of the melted fuel – which could take decades – is not going to begin until 2022.

Eighteen thousand people were killed throughout the whole incident, and 100,000 were displaced. The disaster has widely been considered the worst nuclear disaster since the 1986 meltdown at Chernobyl in the Ukraine.

Initial reports indicated that much of the contamination was contained in the aftermath of the 2011 disaster. But coinciding with the fifth anniversary of the meltdown, a report indicated that 10,000 additional cancer cases would be expected in the region of Japan that is most affected. Also in 2015, an American scientist contended that the Fukushima site was uncontrolled, and was leaking radioactive cesium and strontium in the Pacific Ocean. Last year, in advance of the sixth anniversary, the utilities charged with the cleanup announced that decommission of some of the fuel at one of the three damaged reactors had to be delayed, due to increased radiation.

https://www.laboratoryequipment.com/news/2018/03/fukushima-disaster-released-uranium-unexpected-particles-0

March 2, 2018 Posted by | Fukushima 2018 | , , , | Leave a comment

New evidence of nuclear fuel releases found at Fukushima

February 28, 2018
Uranium and other radioactive materials, such as caesium and technetium, have been found in tiny particles released from the damaged Fukushima Daiichi nuclear reactors.
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“Our research strongly suggests there is a need for further detailed investigation on Fukushima fuel debris, inside, and potentially outside the nuclear exclusion zone,” said Dr Gareth Law.
 
Uranium and other radioactive materials, such as caesium and technetium, have been found in tiny particles released from the damaged Fukushima Daiichi nuclear reactors.
This could mean the environmental impact from the fallout may last much longer than previously expected according to a new study by a team of international researchers, including scientists from The University of Manchester.
The team says that, for the first time, the fallout of Fukushima Daiichi nuclear reactor fuel debris into the surrounding environment has been “explicitly revealed” by the study.
The scientists have been looking at extremely small pieces of debris, known as micro-particles, which were released into the environment during the initial disaster in 2011. The researchers discovered uranium from nuclear fuel embedded in or associated with caesium-rich micro particles that were emitted from the plant’s reactors during the meltdowns. The particles found measure just five micrometres or less; approximately 20 times smaller than the width of a human hair. The size of the particles means humans could inhale them.
The reactor debris fragments were found inside the nuclear exclusion zone, in paddy soils and at an abandoned aquaculture centre, located several kilometres from the nuclear plant.
It was previously thought that only volatile, gaseous radionuclides such as caesium and iodine were released from the damaged reactors. Now it is becoming clear that small, solid particles were also emitted, and that some of these particles contain very long-lived radionuclides; for example, uranium has a half-life of billions of years.
Dr Gareth Law, Senior Lecturer in Analytical Radiochemistry at the University of Manchester and an author on the paper, says: “Our research strongly suggests there is a need for further detailed investigation on Fukushima fuel debris, inside, and potentially outside the nuclear exclusion zone. Whilst it is extremely difficult to get samples from such an inhospitable environment, further work will enhance our understanding of the long-term behaviour of the fuel debris nano-particles and their impact.”
The Tokyo Electric Power Company (TEPCO) is currently responsible for the clean-up and decommissioning process at the Fukushima Daiichi site and in the surrounding exclusion zone. Dr Satoshi Utsunomiya, Associate Professor at Kyushu University (Japan) led the study.
He added: “Having better knowledge of the released microparticles is also vitally important as it provides much needed data on the status of the melted nuclear fuels in the damaged reactors. This will provide extremely useful information for TEPCO’s decommissioning strategy.”
At present, chemical data on the fuel debris located within the damaged nuclear reactors is impossible to get due to the high levels of radiation. The microparticles found by the international team of researchers will provide vital clues on the decommissioning challenges that lie ahead.
 
Story Source:
Materials provided by Manchester University. Note: Content may be edited for style and length.
 
Journal Reference:
1. Asumi Ochiai, Junpei Imoto, Mizuki Suetake, Tatsuki Komiya, Genki Furuki, Ryohei Ikehara, Shinya Yamasaki, Gareth T. W. Law, Toshihiko Ohnuki, Bernd Grambow, Rodney C. Ewing, Satoshi Utsunomiya. Uranium Dioxides and Debris Fragments Released to the Environment with Cesium-Rich Microparticles from the Fukushima Daiichi Nuclear Power Plant. Environmental Science & Technology, 2018; DOI: 10.1021/acs.est.7b06309
 

 

March 1, 2018 Posted by | Fukushima 2018 | , , , | Leave a comment