Fukushima Insoluble Radioactive Particles (part 3)

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We are presenting here a transcription of an NHK TV documentary (note1) on insoluble radioactive particles found in Fukushima and in the Tokyo metropolitan region. This is the 3rd part of the 3 parts.

Her is the 1st part : https://fukushima311voices.wordpress.com/2017/07/14/insoluble-radioactive-particles-part-1/

Here is the 2nd part : https://fukushima311voices.wordpress.com/2017/07/14/insoluble-radioactive-particles-part-2/

 

As you can see below, small insoluble radioactive particles are dispersed in the Tokyo metropolitan area. We believe that this represents serious health problems for the population in terms of internal irradiation, since the insoluble radioactive particles remain in the body for a long time. For anybody who would stay in this metropolitan area, further radioprotection against internal irradiation would be required.

 

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Takeda: I will ask Yuichi Moriguchi, who is carrying out investigations on radio-contamination caused by the accident, including the insoluble radioactive particles, how many of such insoluble radioactive particles exist and in what range of area?

Moriguchi: There are many different sizes of particles, but relatively large particles have been found only near the nuclear power plant. On the other hand, we know that the smaller particles were transported far by the wind and reached the Kanto region.

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Kamakura: Please see here for the details.
Mr. Moriguchi and his colleagues have divided the insoluble radioactive particles into two major types.  They are called type A and type B.
Those of type A are comparatively small with a size of 10 micrometers or less. A lot of them are spherical. What is called a cesium ball is of this type. Since they are small in size, these particles are likely to reach the lungs by breathing.
On the other hand, those of the type B are comparatively large, by more than several tens of micrometers, and most of them are of distorted shape. Because the particle is large, it is not possible to enter the lungs, but it may adhere to the skin and mucous membranes.

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Kamakura: Please see here for the details.
Mr. Moriguchi and his colleagues have divided the insoluble radioactive particles into two major types.  They are called type A and type B.
Those of type A are comparatively small with a size of 10 micrometers or less. A lot of them are spherical. What is called a cesium ball is of this type. Since they are small in size, these particles are likely to reach the lungs by breathing.
On the other hand, those of the type B are comparatively large, by more than several tens of micrometers, and most of them are of distorted shape. Because the particle is large, it is not possible to enter the lungs, but it may adhere to the skin and mucous membranes.

The areas where each type are scattered are gradually coming to be known.
A relatively large, heavy type B particle has been found within 20 kilometers of the Fukushima Daiichi nuclear power plant. On the other hand, small light type A particles are found in the Kanto region.

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According to the simulation in the paper published by the meteorological laboratory, the type A particles were diffused like this by the wind on March 14-15 immediately after the accident.

Takeda: Smaller type A particles flew to the Kanto region immediately after the accident. Could you explain more?

Moriguchi: This is exactly what we are researching right now. The other day I presented a paper at an Academic society. We knew that radioactive materials had reached the Kanto area on March 15, but we found that there were insoluble radioactive particles among them. We are trying to clarify right now as to why they arrived there. We are coming to know gradually that the radioactive materials are likely to have been discharged at a certain time.

Takeda: Just for confirmation: these are the ones that flew in the period between March 14 and 15?

Moriguchi: Yes, that’s right.

Takeda: Do you have any estimation of the amount that has been transported in the wind?

Moriguchi: As a whole, I still don’t know how much has been scattered, but as for what flew to the Kanto area on March 15, we have the result of another research group, according to which 80% to 90% of the radioactive materials are composed of this insoluble type A particle. I think that it’s necessary to evaluate the influence carefully because it has reached a considerably large area from Fukushima Prefecture to the Kanto region.

Takeda: Mr. Kai, what is your opinion of the health effect of the A type?

Kai: In the case of radiation, there are external and internal radiation effects. According to the report of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the influence of external radiation is larger. Therefore, although it is necessary to review the effects of internal radiation due to the discovery of such insoluble particles, the over-all effects including external radiation do not change much, even when the effects of internal radiation have changed. However, the evaluation of internal radiation needs to be reviewed properly in any case.

Takeda: The UNSCEAR has evaluated that there is no health impact due to the amount of radiation in the metropolitan area. Is there a possibility that this evaluation is reversed?

Kai: In that sense, the influence of the internal radiation exposure will change, but I do not think that their evaluation will be revised, because it is assumed that the influence of external exposure is larger.

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Kamakura: On the other hand, there are people who had been evacuated and recently returned to the vicinity of the nuclear power plant.
What are the reactions of the local governments about this insoluble radioactive particle?
For example, the environmental policy section of Okuma town says: “No special measures have been taken, but when people enter a difficult-to-return area, we tell them to wear a protective suit and a mask, and to be careful not to blow up the dust when cleaning the room.”
As you can see, all municipalities are basically dealing with the protective measures that have been carried out so far such as avoiding adhesion to the body and inhaling radioactive materials.

Takeda: Mr. Moriguchi, the evacuation orders have been lifted near the nuclear power plant, and some people have started to return. What are the points to be careful about?

Moriguchi: The decontamination work is done, and the evacuation orders are lifted because the radiation dose has dropped, but the fact is that the decontamination work was carried out only outdoors. Moreover, even in places where the radiation dose is comparatively low, there are areas where such radioactive particles entered residential rooms immediately after the accident. Therefore, I think it is necessary to take the radioprotection seriously.

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Takeda: There is another problem that researchers are concerned about in the issue of  insoluble radioactive particles. It is a problem called “re-scattering”, that is to say, particles are re-raised and scatted from the areas where decontamination has not been done, including the site of the nuclear power plant. In fact, a case of re-scattering was already observed in the past.
On August 19, 2013, at Fukushima Daiichi nuclear power plant, following the decommissioning plan, the debris removal work was on the way at the reactor #3. But… the radiation dose increased on the premises. The workers’ body pollution occurred.

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At this time, Kyoto University’s research group observed an increase in atmospheric radioactive materials at a point about 26 kilometers away from the nuclear power plant. In addition, insoluble radioactive particles were collected at observation facilities between the nuclear power plant and the Kyoto University observation point.

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The research group at Kyoto University simulated the scattering of radioactive particles based on the weather data of the day.  As a result, it was learned that the particles that had been lifted in the debris removal work had scattered over a wide range and reached the observation point.

Takeda: What is your point of view about the health effect of this re-scattering?

Kai: I think that the dose is relatively small, but it is important to take the measurements properly and keep watching. I think that it is especially important to pay attention to measurement results of the round the clock dust monitors installed in the vicinity of the nuclear power plant.

Takeda: How about you, Mr. Moriguchi? What do you think of the measures to take against the problem of re-scattering?

Moriguchi: About the re-scattering, if a big problem happens, most probably it will be in connection with the decommission work. So this is the first thing to be careful about.

Takeda: Another thing: what are the effects of insoluble radioactive particles on the agricultural crops?

Moriguchi: They are actually monitored rigorously. The monitoring in the atmosphere is done as well as the rigorous control of farm products. I think that it is important to diffuse the information thoroughly.

Takeda: You mean that we can trust the products which are put in the market?

Moriguchi: I think that the monitoring is done well.

Takeda: Mr. Moriguchi and Mr. Kai are continuing the research to find out the range of  the scattered particles, and also to evaluate the irradiation dose. They are hoping to have the results by the end of the fiscal year (the end of March).
Researchers are currently trying to clarify the risks of insoluble radioactive particles. And we are going to continue our investigations.
This may cause anguish to some people, but we think that it’s important to receive the information calmly for now.

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Note 1: Close-up Gendai, Genpatsu jiko kara 6 nen, Michi no hoshasei ryushi ni semaru (Approaching radioactive particles six years from nuclear accident) (diffusion: 2017 June 6)

https://fukushima311voices.wordpress.com/2017/07/16/insoluble-radioactive-particles-part-3/

 

Fukushima Insoluble Radioactive Particles (part 2)

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We are presenting here a transcription of an NHK TV documentary (note1) on insoluble radioactive particles found in Fukushima and in the Tokyo metropolitan region. This is the 2nd part of the 3 parts.

Here is the first part.

 

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Insoluble radioactive particles that do not dissolve in water.

This characteristic is supposed to make a big difference when considering health effects.

In the past, radioactive cesium emitted in the nuclear accident was thought to be carried away adhering to water-soluble particles called aerosols in the atmosphere. When it touches the water the particle melts and the cesium diffuses and gets diluted. The same is true when it is inhaled in the lungs; the water-soluble cesium melts into the body fluid and spreads thinly throughout the body. Then it is supposed to be discharged gradually by the metabolic activity, and decreases by half from 80 to 100 days in the case of adults.

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Insoluble radioactive particles, on the other hand, do not dissolve in body fluids. For example, if they adhere to the alveoli at the furthest areas of the lungs, it may take years to discharge. Even with the same amount of cesium, the dose of lung exposure is about 70 times higher than in the case of water-soluble cesium in the case of adults. As for the infants who are more radiosensitive, the dose of exposure is supposed to be approximately 180 times higher.

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In fact, this insoluble radioactive particle has not been identified in past nuclear accidents. Why was it emitted in the accident of the Fukushima nuclear power plant?

Yukihiko Sato, who is doing research on this particle, is focusing on the insulation material that contains glass components. It is used in parts such as piping in the nuclear power plant.

A special electron microscope is used to analyze the proportion of elements contained in the radioactive particles and in the insulation material.

The top is radioactive particles, and the bottom is the insulation material.

The proportion of elements, such as silicon and oxygen, which are the main components of glass, is well matched.

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From this, Mr. Sato thought about the scenario where the radioactive particle formed as follows:

Radioactive cesium was emitted from the melted nuclear fuel in the event of the accident. It first filled the reactor. Then, it leaked into the reactor containment building.

Cesium was absorbed in the insulation material in the building.

After that, a nuclear reactor building blew up by hydrogen explosion.

As the insulation material melts and becomes glass, cesium is taken in. And with the explosion, it became small particles as it dispersed in the blast.

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The radioactive particles found by Sato are in diameter from 0.5 to 500 micrometer. Their shapes vary from a smooth round one to a rugged one.

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Tatsuhiko Sato of the Japan Atomic Energy Agency.

He simulated the health effects of insoluble radioactive particles using a program to calculate the behavior of each ray. For the simulation, he used a particle of the size which enters the lung, and which is actually found. He compared the simulation of the insoluble radioactive particles remaining to adhere to the same spot on the surface of the organ, and that of the same amount of radioactive material adhered uniformly on the surface.

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In the case of uniform adhesion, even after 24 hours, blue and light blue areas are spread out indicating that the radiation dose is low.

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On the other hand, in the case of the particle, the dose near the spot increases locally and orange and red areas are expanding.

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Even with the same quantity of radioactive materials, the health effect may change.

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In fact, there are data of people who may have inhaled insoluble radioactive particles. This is a survey of TEPCO employees who had a large amount of exposure during the nuclear accident.

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The amount of the radioactive materials in the body is examined regularly, and the graph in red shows that the value of the vicinity of the chest is comparatively high. While the radioactive cesium that had spread throughout the body decreased over time, only around the chest the speed to decrease was slow. The inhaled insoluble radioactive particles are suspected to remain in the lungs.

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However, researchers say that the amount is not significant enough to worry about the health effects, according to the International Commission on Radiological Protection.

Takeda: Mr. Michiaki Kai is a specialist in the radio-induced health damages and radioprotection.

If the insoluble radioactive particles stay in the body, the radiation dose may increase locally. And according to some experts, it is necessary to investigate the health effects. What is your opinion?

Kai: First of all, you know that the dose is a measure of health effects. However, when we compare the dose, you cannot compare the cases of smaller and larger exposures ranges. In general, the greater the exposures range, the greater the health impact is. In that sense, the larger the average dose of an organ or an entire system is, the greater the impact is. Therefore, it is important to evaluate the average organ dose even in the case of the insoluble particle. However, there is a possibility that the dose becomes high very locally, so it is important to evaluate it properly, since some people worry about it. This is why such an evaluation is carried out.

Takeda: The overall exposure more than local exposure is …

Kai: If it is the same dose, the impact on health is larger if the range of exposure is wider.

Takeda: You mean that the impact is larger, but it is also necessary to examine a local exposure.

Kai: I think that it is necessary to examine it properly.

(To be continued in the Part 3)

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Note 1: Close-up Gendai, Genpatsu jiko kara 6 nen, Michi no hoshasei ryushi ni semaru (Approaching radioactive particles six years from the nuclear accident) (diffusion: 2017 June 6)

https://fukushima311voices.wordpress.com/2017/07/14/insoluble-radioactive-particles-part-2/

 

Fukushima Insoluble Radioactive Particles (part 1)

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We are presenting here a transcription of an NHK TV documentary (note1) on insoluble radioactive particles found in Fukushima and in the Tokyo metropolitan region. Since it is quite heavy with images, it will be uploaded in 3 parts.

These particles contain cesium, which has the property to dissolve in water. However, in the case of these particles, the cesium was taken into glass-like particles during the Fukushima Daiichi NPP accident before it was blown away by the explosion. These particles do not dissolve in water, and as a consequence the cesium will remain longer both in the environment and in the human body, which will modify the impact of radioactive materials on the environment and on health.

Here the video in Japanese: https://youtu.be/ipOEfS-06FM

Takeda: A round particle like a marble.
Rugged particles like asteroids.
Presently, the researchers are paying attention to them.

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Very small particles contain radioactive cesium.
Therefore, sometimes they are called “cesium balls”.
They are radioactive particles emitted during the TEPCO Fukushima Daiichi nuclear power plant accident.

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Their existence came to light recently and the investigation is ongoing.
The reason why researchers pay attention is their nature of not dissolving in water.
They are called “insoluble radioactive particles”.
Because of this characteristic, they are considered to stay in the environment for a long time.
 If inhaled, they may remain in the human body for a long time, but the impact is not yet fully known.
While the evacuation orders are being lifted, the researchers began to raise their voices that they should communicate the information known at this stage.

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Six years since the accident.
The reality of the insoluble radioactive particles has gradually become clear.
This is the latest research report.

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First, these are the areas where evacuation orders were issued following the Fukushima Daiichi nuclear power plant accident.
In areas where decontamination works have been completed, evacuation orders have been lifted from the end of March and the return movement of the population has begun.
It is in this context that in this year, the research presentations on insoluble radioactive particles have come out in succession.

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Kamakura: Among the radioactive material released during the accident, it is radioactive cesium that is still regarded as a problem. Especially this cesium 137. Most of the radioactive materials that remain in the environment are cesium 137 because they are released in large quantities and have a long half-life of 30 years. Until now, cesium has been thought to dissolve in water and gradually become diluted in the environment. However, cesium is found in insoluble state that does not dissolve in water.

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Takeda: Many aspects of the insoluble radioactive particles remain unknown, such as where they exist and in what quantity, or how they affect the health.
Today, we wanted to share the information known to us at this point, including the things that remain unclear yet, in order to provide a base to make decisions on this issue.
First of all, we shall see what the insoluble radioactive particles are.
And then, we will have a look to see in what measure the impact on health is known.

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A symposium was held in March this year on the irradiation due to the nuclear accident.
Tatsuhiko Sato of the Japan Atomic Energy Agency presented a paper on the health effects of insoluble radioactive particles, which were hardly known so far.

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Where are insoluble radioactive particles located?
We accompanied various investigations in difficult-to-return areas.
We entered a building abandoned since immediately after the accident.
We collected dust accumulated in a room.
We took it back to the lab and analyzed it….
A number of black dots emerged. It shows that there are radioactive materials.
We carried out a further examination of the part where the black dots are located.
We came to a small particle.

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This is an insoluble radioactive particle.
The measurement has proven that radioactive cesium of approximately 60 becquerels is included in the particle of about 200 micrometers.
There are 27 buildings in the survey. In all the buildings similar radioactive particles have been found.

(to be continued in Part 2)

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Note 1: Close-up Gendai, Genpatsu jiko kara 6 nen, Michi no hoshasei ryushi ni semaru (Approaching radioactive particles six years from nuclear accident) (diffusion: 2017 June 6)

https://fukushima311voices.wordpress.com/2017/07/14/insoluble-radioactive-particles-part-1/

 

The Different Dangerosity of Some Radioactive Elements.

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One night in July 2013, Xavier Nast, a French antinuclear activist, who many years before used to work at COGEMA, presently named AREVA, took the time to explain me the diffrence between some of the radioactive elements, in terms of their dangerosity.
 
As Xavier Nast told me, nothing is worth practical exercises to understand what is not always obvious at the first explanation.
 
Since the beginning of the Fukushima accident, everyone understands the situation as he/she perceives it, and everyone is right it is very serious indeed, but still we haven’t seen almost anything yet. And what we may risk to see and understand?
 
When sharing the “galette des rois”in France, some king cakes in the old days were stuffed with a a small gold coin (a gold Napoleon). If a greedy one swallowed it inadvertently, he will have to wait one to two days to recover it but his health will not be affected. https://en.wikipedia.org/wiki/King_cake
 
Imagine the coins gold plated and filled with actinides (highly toxic alpharadio transmitters) such as they all weigh 6 grams, have a diameter of 21 mm and the same visual appearance:
A) An Uranium 238 filled gold plated coin
B) A Plutonium 239 filled gold plated coin
C) A Plutonium 238 filled gold plated coin
D) A Polonium 210 filled gold plated coin
 
We will not see any difference in appearance and weight.
 
However the threshold for the lethal dose of an inhaled monolithic dust is:
0.835gram for A (Uranium 238)
0.000 000 4 gram for B (Plutonium 239)
0.000 000 001 6 gram for C (Plutonium 238)
0.000 000 000 007 gram for D (Polonium 210)
 
This means that the lethal dose of these coins could destroy:
6 lives for A (Uranium 238, there is a lot)
13,475,000 lives for B, more than Paris Metropolis population (Plutonium 239,there is a lot)
3,700,000,000lives for C, more than half of mankind (Plutonium 238 is rare)
850 billion lives for D, 120 times the world population. (Polonium 210 is very rare)
 
Yet these coins A, B, C and D have not caused you any damage after being swallowed, not even long after.Because they were all covered with a tenth mm of gold , which prevented the huge flow of alpha particles to destroy even just a little of your digestive tract.
 
Conclusion:alpha emitters radionuclides must remain CONFINED.
 
We therefore better have no nuclear plant to explode, especially one of those nuclear plants using MOX, as MOX fuel consists of 7% plutonium 239 mixed with depleted uranium, such as the ones we have many in France.
 
Knowing this, are you still willing for them to continue using their deadly nuclear technology? Do you still believe that civil nuclear is safe?

 

 

 

Radioactive material from Fukushima plant coming back to Japan in the Pacific

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Prof. Aoyama from Institute of Environmental Radioactivity of Fukushima University reported that the radioactive material discharged from Fukushima plant circulated in the Pacific to come back to Japan offshore.

He implemented seawater analysis at 71 points from 11. 2015 to 2. 2016. The analysis is partially completed to show radioactive material has spread to the South West offshore of Japan. 2 Bq/m3 of Cs-137 was detected in seawater from South West offshore of Kyushu. 1.83 Bq/m3 was detected even offshore of the west coast of Japan.

0.38 Bq/m3 of Cs-134 was also measured to prove this is from Fukushima accident.

It is assumed that the discharged Cs-134/137 travelled to the east in the Northern Pacific. It was carried to the South and West to come back to Japan by taking 2 ~ 3 years.

He comments it is possible that the density of radioactive material increases from now.

http://www.asyura2.com/16/genpatu45/msg/611.html

http://fukushima-diary.com/2016/05/radioactive-material-from-fukushima-plant-coming-back-to-japan-in-the-pacific/

Fukushima plant begins testing waste incinerators

”The operator says it expects to burn up to 14 tons of waste per day. But the resulting ash will have a higher concentration of radioactive materials than the waste has before it is burned.”

Fukushima plant begins testing waste incinerators
The operator of Fukushima Daiichi has begun testing an incinerator facility at the damaged nuclear power plant. The facility will be used for burning used protective gear and other waste produced during the decommissioning of the plant’s reactors.

Tokyo Electric Power Company initially planned to start testing the two incinerators at the facility on February 10th. But a water leak forced a delay.

Workers on Thursday began testing one of the incinerators, which had been repaired.

At the end of last year, there were about 66,000 cubic meters of waste being stored at the plant after nearly five years of decommissioning work following the March 2011 accident. That is enough to fill more than 100 swimming pools 25 meters in length.
The incinerators are expected to reduce the volume of waste by about 90 percent. The waste includes used disposable protective gear, clothing, sheets, cardboard and timber.

The operator says it expects to burn up to 14 tons of waste per day. But the resulting ash will have a higher concentration of radioactive materials than the waste has before it is burned.

TEPCO says filters installed in the smokestack will prevent the release of radioactive substances. The ash will be stored in drums inside a secure building.

Tokyo Electric Power said it will dispose of some four tons of waste in Thursday’s test. It said it will start testing the other incinerator on Sunday.
http://www3.nhk.or.jp/nhkworld/en/news/20160225_25/

TEPCO begins burning radiation-tainted work clothes at Fukushima plant
OKUMA, Fukushima Prefecture–Tokyo Electric Power Co. has started to incinerate the thousands of boxes of lightly contaminated waste, including clothing used by workers, at the Fukushima No. 1 nuclear power plant to reduce the amount of tainted waste on the site.
TEPCO, the plant operator, fired up a special on-site incinerator on Feb. 25 to burn protective suits, gloves, socks and other work clothes worn by plant workers that became contaminated with low-level radiation.
The operation will reduce the amount of tainted work clothing accumulating at the plant during decommissioning operations since the nuclear disaster unfurled in March 2011. The garments cannot be processed outside the plant due to the radiation.
The clothing being incinerated are items with the lowest levels of contamination that have been stored in tens of thousands of 1 cubic-meter special boxes. The number of containers reached 66,000 at the end of last year.
The incinerator is equipped with two types of filters that can reduce the radioactive levels of the exhaust air to less than one-millionth, while reducing the capacity of the waste to about 2 percent.
The incinerator can burn a maximum of 14 tons of items per day when it is operated to capacity for 24 hours. The ash residue will be stored in metallic barrels on the plant compound.
The incineration project was authorized by the Nuclear Regulation Authority in July 2014. TEPCO began operational tests of the incinerator using untainted waste last fall.
http://ajw.asahi.com/article/0311disaster/fukushima/AJ201602260071

Fukushima ice wall shown to media

An incinerator in Fukushima Daiichi means more incineration, which add more radioaticle nanoparticles dispersed into the air and into the environment.

The operator of the damaged Fukushima nuclear power plant has shown media outlets the site where work has been completed for an underground ice wall. The wall is designed to stop underground water from flowing into the plant’s reactor buildings.

Tokyo Electric Power Company, or TEPCO, began construction of the wall in 2014. Its work was completed earlier this month.

The wall is designed to freeze the soil around the Number 1 to Number 4 reactor buildings in order to keep groundwater from seeping into the structures.

TEPCO has driven about 1,500 pipes carrying refrigerant liquid into the ground around the buildings. The pipes and cooling devices were shown to the media on Tuesday.

But workers have not yet injected a freezing agent into the pipes. This is due to concerns that a sudden drop in groundwater levels may result in the release of radioactive water. TEPCO officials are examining the situation with the Nuclear Regulation Authority, or NRA.

Masato Kino of the Agency for Natural Resources and Energy is in charge of dealing with the contaminated water. He says now that the ice wall is completed, his agency is consulting with the NRA to reduce the volume of radioactive water at the plant.

TEPCO officials also showed the media an incinerator that will burn contaminated waste such as used protective suits.

Officials plan to start testing the incinerator on Thursday.
They hope it will help reduce about 66,000 cubic meters of waste that has accumulated at the plant.
http://www3.nhk.or.jp/nhkworld/en/news/20160223_32/