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Health Effects of Plutonium

Here is a 1997 article by a nuclear fission expert on the health effects of the deadly substance.
 
plutonium_pellet.jpg
Plutonium pellet
By Dr Arjun Makhijani
Institute for Energy and Environmental Research
December 1997
 
Plutonium-239 is a very hazardous carcinogen which can also be used to make nuclear weapons. This combination of properties makes it one of the most dangerous substances. Plutonium-239, while present in only trace quantities in nature, has been made in large quantities in both military and commercial programs in the last 50 years. Other more radioactive carcinogens do exist, like radium-226, but unlike plutonium-239 cannot be used to make nuclear weapons, or are not available in quantity. Highly enriched uranium (HEU) can also be used to make nuclear weapons, but it is roughly one thousand times less radioactive than plutonium-239. The danger is aggravated by the fact that plutonium-239 is relatively difficult to detect once it is outside of secure, well-instrumented facilities, or once it has been incorporated into the body. This is because its gamma ray emissions, which provide the easiest method of detection of radionuclides, are relatively weak.
 
The main carcinogenic property of plutonium-239 arises from the energetic alpha radiation it emits. Alpha particles, being heavy, transfer their energy to other atoms and molecules within fewer collisions than the far lighter electrons which are the primary means of radiation damage for both gamma and beta radiation.1 Alpha particles travel only a short distance within living tissue, repeatedly bombarding the cells and tissue nearby. This results in far more biological damage for the same amount of energy deposited in living tissue. The relative effectiveness of various kinds of radiation in causing biological damage is known as “relative biological effectiveness” (RBE). This varies according to the type of radiation, its energy, and the organ of the body being irradiated. A simple factor, called quality factor, is used to indicate the relative danger of alpha, beta, gamma and neutron radiation for regulatory purposes. The International Commission on Radiation Protection currently recommends the use of a quality factor of 20 for alpha radiation relative to gamma radiation.2
 
Once in the body, plutonium-239 is preferentially deposited in soft tissues, notably the liver, on bone surfaces, in bone marrow and other non-calcified areas of the bone, as well as those areas of the bone that do not contain cartilage. Deposition in bone marrow can have an especially harmful effect on the blood formation which takes place there. By contrast, radium-226, another alpha emitter, is chemically akin to calcium and so becomes deposited in the calcified areas of bones.
 
When it is outside the body, plutonium-239 is less dangerous than gamma-radiation sources. Since alpha particles transfer their energy within a short distance, plutonium-239 near the body deposits essentially all of its energy in the outer dead layer of the skin, where it does not cause biological damage.
 
The gamma rays emitted due to plutonium-239 decay penetrate into the body, but as these are relatively few and weak, a considerable quantity of plutonium-239 would be necessary to yield substantial doses from gamma radiation. Thus, plutonium-239 can be transported with minimal shielding, with no danger of immediate serious radiological effects. The greatest health danger from plutonium-239 is from inhalation, especially when it is in the common form of insoluble plutonium-239 oxide. Another danger is absorption of plutonium into the blood stream through cuts and abrasions. The risk from absorption into the body via ingestion is generally much lower than that from inhalation, because plutonium is not easily absorbed by the intestinal walls, and so most of it will be excreted.
 
The kind of damage that plutonium-239 inflicts and the likelihood with which it produces that damage depend on the mode of incorporation of plutonium into the body, the chemical form of the plutonium and the particle size. The usual modes of incorporation for members of the public are inhalation or ingestion. Plutonium may be ingested by accidental ingestion of plutonium-containing soil, or through eating and drinking contaminated food and water. Incorporation via cuts is a hazard mainly for workers and (in former times) for personnel participating in the atmospheric nuclear testing program.
 
In general, plutonium in the form of large particles produces a smaller amount of biological damage, and therefore poses a smaller risk of disease, than the same amount of plutonium divided up into smaller particles. When large particles are inhaled, they tend to be trapped in the nasal hair; this prevents their passage into the lungs. Smaller particles get into the bronchial tubes and into the lungs, where they can become lodged, irradiating the surrounding tissue.
 
Other plutonium isotopes that emit alpha radiation, like plutonium-238, have similar health effects as plutonium-239, when considered per unit of radioactivity. But the radioactivity per unit weight varies according to the isotope. For instance, plutonium-238 is about 270 times more radioactive than plutonium-239 per unit of weight.
 
Experimental data
 
The health effects of plutonium have been studied primarily by experiments done on laboratory animals. Some analyses have also been done on workers and non-worker populations exposed to plutonium contamination. Measurements of burdens of plutonium using lung counters or whole-body counters, together with follow-up of exposed individuals, have provided information which is complementary to experimental data and analysis. Experiments injecting human beings with plutonium were also done in the United States. Between 1945 and 1947, 18 people were injected with plutonium in experiments used to get data on plutonium metabolism. They were done without informed consent and have been the object of considerable criticism since information about them became widely known in 1993.
 
Experiments on beagles have shown that a very small amount of plutonium in insoluble form will produce lung cancer with near-one-hundred-percent probability. When this data is extrapolated to humans, the figure for lethal lung burden of plutonium comes out to about 27 micrograms. Such an extrapolation from animals, of course, has some uncertainties. However, it is safe to assume that several tens of micrograms of plutonium-239 in the lung would greatly increase the risk of lung cancer. Larger quantities of plutonium will produce health problems in the short-term as well.
 
The precise quantitative effects of considerably lower quantities of plutonium are as yet not well known. This is due to several factors such as: the difficulty of measuring plutonium in the body; uncertainties regarding excretion rates and functions due to the large variation in such rates from one human being to the next (so that the same body burden of plutonium would produce considerably different doses); complicating factors such as smoking; uncertainties in the data (as, for instance, about the time of ingestion or inhalation); differing and largely unknown exposure to other sources of carcinogens (both radioactive and non-radioactive) over the long periods over which studies are conducted; failure to study and follow-up on the health of workers who worked with plutonium in the nuclear weapons industry to the extent possible.
 
One of the few attempts to analyze the effects of microgram quantities of plutonium on exposed human subjects was a long-term study of 26 “white male subjects” from the Manhattan Project exposed to plutonium at Los Alamos in 1944 and 1945, where the first nuclear weapons were made. These subjects have been followed for a long period of time, with the health status of the subjects periodically published. The most recent results were published in a study in 1991.3
 
The amounts of plutonium deposited in the bodies of the subjects were estimated to range from “a low of 110 Bq (3 nCi) …up to 6960 Bq (188 nCi),”4 corresponding to a weight range of 0.043 micrograms to 3 micrograms. However, weaknesses in the study resulted in considerable uncertainties about the amount and solubility of plutonium actually incorporated at the time of exposure.5
 
Of the seven deaths by 1990, one was due to a bone cance (bone sarcoma).6 Bone cancer is rare in humans. The chances of it normally being observed in a group of 26 men over a 40-year timeframe is on the order one in 100. Thus, its existence in a plutonium-exposed man (who received a plutonium dose below that of current radiation protection guidelines) is significant. 7 There are data for plutonium exposure in other countries, notably in Russia. These are still in the process of being evaluated. Collaborative US-Russian studies are now beginning under the Joint Coordinating Committee on Radiation Effects Research (JCCRER) to assess the health effects of the Mayak plant to both workers and neighbors of the facility.
 
Endnotes
 
1. Gamma rays consist of high energy photons, which are “packets” or quanta of electromagnetic energy.
 
2. The energy deposited in a medium (per unit of mass) is measured in units of grays or rads (1 gray = 100 rads), while the biological damage is measured in sieverts or rems (1 sievert = 100 rems).
 
3. G.L.Voelz and J.N.P. Lawrence, “A 42-year medical follow-up of Manhattan project plutonium workers.” Health Physics, Vol. 37, 1991, pp. 445-485.
 
4. Ibid., p. 186.
 
5. These aspects of the study are discussed in some detail in Gofman 1981, pp. 510-520 (based on the status of the Manhattan Project workers study as published in Voelz 1979). See J.W. Gofman, Radiation and Human Health, (San Francisco: Sierra Club Books, 1991), p. 516.
 
6. Three of these deaths were due to lung cancer. It is difficult to assess the significance of this large percentage, since all three were smokers.
 
7. Voelz, p. 189.
 
Arjun Makhijani, President of IEER, holds a Ph.D. in engineering (specialization: nuclear fusion) from the University of California at Berkeley. He has produced many studies and articles on nuclear fuel cycle related issues, including weapons production, testing, and nuclear waste, over the past twenty years. He is the principal author of the first study ever done (completed in 1971) on energy conservation potential in the U.S. economy. Most recently, Dr. Makhijani has authored Carbon-Free and Nuclear-Free: A Roadmap for U.S. Energy Policy (RDR Books and IEER Press, 2007), the first analysis of a transition to a U.S. economy based completely on renewable energy, without any use of fossil fuels or nuclear power. He is the principal editor of Nuclear Wastelands and the principal author of Mending the Ozone Hole, both published by MIT Press.
 
Also see: Radioactive iodine releases from Japan’s Fukushima Daiichi reactors may exceed those of Three Mile Island by over 100,000 times, March 25, 2011.
 
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February 22, 2018 Posted by | - plutonium | , | Leave a comment

Japan’s bomb in the basement

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Under the guise of a civil nuclear program, Japan has become a de-facto nuclear weapons state without so far having to take that next fateful step.

On Thursday, a shipment of 700 kilograms of plutonium arrived in Japan after a journey by sea from the French port of Cherbourg. That’s enough material for more than 100 nuclear weapons.

The plutonium – in the form of atomic fuel known as MOX, a mix of uranium and plutonium oxide – is for use in the Takahama-4 reactor, owned by Kansai Electric Power Co. and located on Wakasa Bay, in western Japan near Osaka.

There have been six shipments of such highly toxic cargoes since 1999, the result of an agreement to send radioactive spent fuel in Japan for reprocessing in France and the UK, and then to be shipped back as plutonium MOX fuel for use in Japan’s reactors.

Putting aside the reactor fuel issue for the moment, Japan’s plutonium program must be seen in the context of the nuclear arms proliferation dynamic that has existed for decades in Northeast Asia, but which today has taken on even greater urgency owing to North Korea’s nuclear weapon program.

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Map of Japan’s nuclear plants. Photo: Japan Atomic Industries Forum, 2016.

 

There is no question that Japan has the technical capability to build an advanced nuclear weapons arsenal.

There have been over the decades multiple references to it taking less than six months for Japan to build an atomic weapon – a credible timeframe if it’s true as reported more 20 years ago that a design or designs already exist in the country.

However, to build a ‘credible’ arsenal of weapons would require several years at least.

More important than any actual timeframe are the external factors that would lead a Japanese government to move to nuclear weaponization.

This debate is stirring in Japan. In a TV Asahi program on September 6, former Defense Minister Shigeru Ishiba suggested a review was needed of Japan’s so-called three non-nuclear principles: Not producing, possessing, or allowing nuclear weapons into Japan.

Ishiba asked the question if Japan is under the US nuclear umbrella then isn’t it necessary to allow US nuclear weapons into the country to deter threats from North Korea?

It’s clear that without a peaceful resolution to the underlying security threats in the region, there is an increasing possibility that policy makers in Tokyo – backed by Washington – will decide that Japan should weaponize its plutonium stockpile.

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We have not reached that point yet, but without a fundamental change in thinking and policy, Japan’s nuclear bomb in the basement may not remain there for very much longer.

But back to Japan’s plutonium stockpiles and the question of why the only country attacked by a nuclear weapon and one that espouses the three non-nuclear principles has large amounts of the bomb-making material.

To answer that question requires looking back to the 1950s and a policy that was spearheaded by the United States, but soon adopted by Japan’s Science and Technology Agency established by former Prime Minister Yasuhiro Nakasone.

The policy was to build new types of nuclear power plants, or so-called Fast Breeder Reactors (FBRs), worldwide that would be fueled with plutonium reprocessed from spent uranium fuel. As FBRs produce more fuel than they burn  – hence the name “breeder” – they would in turn generate plutonium to fuel yet more FBRs.

The procedure was known as “closing the nuclear fuel cycle.”

While the idea seems a solution for processing spent fuel and producing more fuel for FBRs, the problem is fast breeder reactor programs failed worldwide, including in Japan.

Japan’s principle FBR started up in 1994 and was called Monju – named after a Buddhist deity for wisdom. However, a fire broke out at Monju 18 months after it opened, which shut the plant down for 14 years.

4Monju nuclear reactor. Photo: IAEA Energy/Flickr

 

It restarted in May 2010, but weeks later a 3.3 metric-ton fuel exchange device fell into the reactor, which shut it down again for good, though to add to the fiasco its computers were later hacked and data stolen.

This effectively ended Japan’s FBR ambitions, though it took two decades and a total investment of more than US$10 billion for the government to finally make the wise decision to terminate Monju in December 2016.

However, Tokyo had other motives for commitment to a plutonium fuel cycle.

By the late 1960’s and early 1970’s, plans to build commercial light water reactors across Japan, such as at Takahama and Fukushima, faced strong opposition from local communities and activists.

To appease the opposition, the government and utilities said the new reactors would not become nuclear waste sites because the spent fuel would be shipped for reprocessing in the UK and France. This solved, temporarily, a major nuclear waste problem at least for Japan.

In total over 7,000 tons of such fuel went off to Europe during the decades up to the mid 1990’s.

During that time, the plants reprocessing Japan’s spent fuel at la Hague in France and Sellafield in the UK became synonymous with accidents, nuclear waste discharges into the ocean and atmosphere, and public health concerns.

While the Japanese contracts were lucrative for the two state owned companies that operated the Sellafield and la Hague plants –Cogema/AREVA in France and British Nuclear Fuels Limited (BNFL) in the UK – both were to become failed entities.

The Sellafield site is now managed by a UK government agency and absorbs most of the nation’s nuclear decommissioning budget estimated well in excess of US$100 billion.

5.jpgSellafield nuclear reprocessing site. Image: Sellafield Ltd.

There is another large wrinkle in this tale.

As failures engulfed Japan’s Monju fast-breeder reactor and shut it down, the government had to figure out what to do with the thousands of kilograms of plutonium that would be returning to Japanese shores to fuel a fleet of FBR’s that didn’t exist.

The answer, which brings us back to the cargo that arrived in Japan this week, was plutonium MOX fuel that could be used in existing commercial light water reactors.

The first MOX shipments in 1999 were for use in Fukushima and Takahama reactors.

However, in the case of the MOX delivered to Takahama, activists revealed that the fuel had been manufactured with falsified quality certification, leading to its return shipment to the UK.

In the case of the Fukushima plant, citizens from the prefecture, supported by evidence from Greenpeace, took Tokyo Electric Power Co., or TEPCO the plant owner, to court over the quality control of the fuel.

While the citizens group lost the case, AREVA was instructed to release vital safety data, which they refused to do. The ensuing controversy led the then Fukushima Governor Eisaku Sato to refuse to permit loading of the plutonium fuel.

It sat in the cooling pool at the Fukushima Daiichi reactor until August 2010 when TEPCO finally loaded the 32 assemblies of 235 kilograms of plutonium into reactor unit 3.

This was just six months before the Fukushima plant was hit by the strongest earthquake ever recorded in Japan and flooded by a tsunami that caused triple reactor meltdowns on March 11, 2011, including reactor unit 3.

Worker wearing protective suit and mask works on roof of No.4 reactor building of TEPCO's tsunami-crippled Fukushima Daiichi nuclear power plant in Fukushima prefectureA worker in protective suit works on the roof of the No.4 reactor building of the  crippled atomic plant in Fukushima prefecture February 20, 2012. Reuters/Issei Kato

 

Without the actions of Japanese citizens and others around the world, TEPCO would almost certainly have spent the past decade through to 2011 loading many tons of plutonium MOX fuel into the Fukushima Daiichi reactors.

The meltdown of this fuel would have been far more severe and with greater onsite and offsite radiological consequences than the reality at the accident site today, which itself will take decades and tens of billions of dollars to clean up.

Worse still, tons of high temperature spent MOX fuel would have been sitting in Fukushima’s spent fuel pools.

If the Fukushima reactors had been loaded with plutonium MOX, then the warning from the Atomic Energy Commission to then Prime Minister Naoto Kan in late March 2011 that the loss of control at the spent fuel pools at the plant may require the evacuation of Tokyo, may well have become a reality.

Of the five reactors now operating in Japan, three are loaded with plutonium MOX fuel. However, the threat from Japan’s plutonium obsession could be about to get a lot worse.

Japan has built its own US$21 billion nuclear spent fuel reprocessing facility in Rokkasho-mura in Aomori prefecture, near Hokkaido. (Yes, the same Hokkaido North Korea has recently taken to firing missiles over.)

7The Rokkasho nuclear fuel reprocessing plant in Japan’s Aomori prefecture. Wikimedia Commons.

 

The Rokkasho story sounds more than a little similar to Monju, just more expensive.

Rokkasho was supposed to be completed in 1997, but due to multiple construction and equipment failures, it was delayed and has since missed repeated start up dates. It’s now 20 years behind schedule and has a new opening set for 2018.

Assuming Rokkasho does eventually open, it was built to process spent fuel to produce plutonium primarily for use in fast-breeder reactors.

As pointed out, Japan’s only fast-breeder reactor, Monju, has been permanently shut so what happens to the 8,000 kilograms of plutonium Rokkasho was to produce each year?

The answer it appears lies in an atomic power plant being built at the northern tip of Aomori prefecture that will contain the Ohma Advanced Boiling Water reactor.

Now planned to start up in 2024, this reactor is intended to have a full MOX core, which would contain over 5 tons of plutonium and an annual demand of around 1.7 tons.

The safety implications of what would be a unique reactor worldwide operating with a full plutonium MOX core are enormous.

One reason why citizens and the city of Hakodate over the Tsugaru straits in Hokkaido have filed court challenges seeking to halt the Ohma plant’s construction. A court judgement is expected later this year.

Like Monju before, the prospects for operation of Ohma are dire and unlikely to solve Japan’s self inflicted plutonium hangover. But that also may be the point – the strategic and national security rationale for the program remains central for a government increasingly nationalistic in tone and outlook.

Under the guise of a civil nuclear program, Japan has become a de-facto nuclear weapons state without so far having to take that next fateful step.

The MOX shipment this week is merely one further fig leaf for a plutonium and nuclear program that was always so much more than about energy.

How long can the Japanese government defend such a policy? We may be about to see in 2018 when the US Japan Peaceful

North Korean leader Kim Jong Un provides guidance on a nuclear weapons program in this undated photo released by North Korea's Korean Central News AgencyKim Jong-un with nuclear weapon engineers in this undated photo released by Korean Central News Agency in Pyongyang September 3, 2017. KCNA via REUTERS

 

Nuclear Cooperation Agreement, that provides sanction for Japan’s program, is up for renewal.

Given the incumbents in the Prime Minister office in Tokyo and the White House, don’t expect much deep reflection (or policy reversal) on what it means for a nation in a region on the edge of major conflict to possess the largest stockpile of nuclear weapons plutonium outside the declared nuclear weaponized states.

Instead, ending this decades long multi-billion dollar program will, as ever, be secured by the dedication of the people of Japan and their allies around the world concerned as they are with public safety and real security built on peace.

Shaun Burnie is a senior nuclear specialist with Greenpeace Germany, Tokyo. He is co-author of “Nuclear Proliferation in Plain Sight: Japan’s Plutonium Fuel Cycle–A Technical and Economic Failure But a Strategic Success” Japan Focus, March 2016, available at http://apjjf.org/2016/05/Burnie.html. He has worked on nuclear issues worldwide for more than three decades, including since 1991 on Japan’s plutonium and nuclear policy. sburnie@greenpeace.org

Nuclear physicist, Professor Frank Barnaby, is formerly of the UK Atomic Weapons Establishment and Director of the Stockholm International Peace Research Institute (SIPRI – from 1971-1981). Prof. Barnaby testified to the Fukushima District Court against TEPCO’s plans for MOX use in Fukushima Daiichi 3 in 2000, and is the author of multiple books on nuclear weapons design and policy.

http://www.atimes.com/article/japans-plutonium-proliferation-energy//

September 22, 2017 Posted by | Japan | , | Leave a comment

Reprocessed nuclear fuel returned to Japan for reactor use

Japan has learned absolutely nothing from the Fukushima Daiichi nuclear plant disaster. This is not going to end well!

This is a mouthful, read this:

“Nuclear fuel reprocessed in France returned to Japan on Thursday for use in a reactor as the country tries to burn more plutonium amid international concerns about its stockpile.”

“The need to reduce its plutonium stockpile adds to Japan’s push to restart reactors, aside from also needing to generate power. It would require 16 to 18 reactors to burn MOX to keep Japan’s plutonium stockpile from growing when the Rokkasho plant starts up, according to government and utility officials.”

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TOKYO- Nuclear fuel reprocessed in France returned to Japan on Thursday for use in a reactor as the country tries to burn more plutonium amid international concerns about its stockpile.

Kansai Electric Power Co said the shipment arrived for use at the No. 4 reactor at its Takahama plant in Fukui Prefecture. The reactor is one of only five reactors currently operating in Japan.

A specialized ship, the Pacific Egret, was seen docked just outside one plant as the heavily protected shipment was brought inside under extremely tight security. The utility said it cannot provide details such as the amount of the fuel. The new fuel is expected to be loaded after the reactor’s regular safety check planned next year.

Japan has a stockpile of 47 tons of plutonium – 10 tons at home and the rest in Britain and France, which reprocess and store spent fuel for Japan as the country still lacks its own capacity to do so. Experts say the amount could be enough to make thousands of atomic bombs, although utility operators deny such risk, saying the material is stored safely and monitored constantly.

Japan plans to start up its Rokkasho reprocessing plant next year, but critics say that would only add to the stockpile problem and nuclear security concerns.

Without the prospect of achieving a plutonium-burning fast reactor in near future, Japan has resorted to burning MOX, a mixture of plutonium and uranium fuel, in conventional reactors.

The need to reduce its plutonium stockpile adds to Japan’s push to restart reactors, aside from also needing to generate power. It would require 16 to 18 reactors to burn MOX to keep Japan’s plutonium stockpile from growing when the Rokkasho plant starts up, according to government and utility officials.

Only three reactors, including two at Takahama, use MOX, with a fourth one expected to start up next year. Restarts come slowly amid persistent ant-nuclear sentiment among the public since the 2011 Fukushima nuclear accident and stricter standards under the post-Fukushima safety requirement.

https://japantoday.com/category/national/reprocessed-nuclear-fuel-returned-to-japan-for-reactor-use

September 22, 2017 Posted by | Japan | , | Leave a comment

Blast from the Past: Plutonium Contamination from Fukushima Daiichi Unit 3

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From Majia’s blog

I was reviewing my notes regarding plutonium found at Fukushima and I found this news story worth remembering:

Amina Khan (of the Los Angeles Times). (March 8, 2012). Plutonium near Fukushima plant poses little risk, study says Published: Thursday, March 8, 2012 http://www.heraldnet.com/article/20120308/NEWS02/703089849

The levels of radioactive plutonium around Japan’s Fukushima Daiichi nuclear power plant aren’t much higher than the amount of plutonium remaining in the environment from Cold War-era nuclear weapons tests, and it probably poses little threat to humans, a new study indicates.

The paper, published Thursday in the journal Scientific Reports, provides the first definitive evidence of plutonium from the accident entering the environment, the authors say. It examines the area within a roughly 20-mile radius of the plant and details the concentration of plutonium isotopes deposited there after explosions ripped open multiple reactors.

At the three sites examined, the levels for certain isotope ratios were about double those attributed to residual fallout from above-ground nuclear tests conducted by the U.S. and former Soviet Union at the dawn of the Cold War….

Robert Alvarez, who has served as a senior policy adviser in the U.S. Energy Department, said he would have been surprised if researchers had not found evidence of plutonium contamination near the plant. “They were irradiating plutonium in Unit 3, which experienced the biggest explosion,” he said. In fact, the explosion was so massive that investigators found fuel rod fragments a mile away, leading to speculation that a supercritical fission event may have also occurred, Alvarez said.

The article is referring to a study by Zheng et al. Here is my synopsis of the study’s findings:

A study released in Scientific Reports published by Nature titled ‘Isotopic evidence of plutonium release into the environment from the Fukushima DNPP accident’ by Zheng et al found that a wide array of highly volatile fission products were released, including 129mTe, 131I, 134Cs, 136Cs and 137Cs, which were all found to be ‘widely distributed in Fukushima and its adjacent prefectures in eastern Japan.’[i]

The study also found evidence of actinides, particularly Pu isotopes, on the ground northwest and south of the Fukushima DNPP in the 20–30 km zones. The study called for long-term investigation of Pu and 241Am dose estimates because of findings of ‘high activity ratio of 241Pu/239+240Pu (> 100) from the Fukushima DNPP accident.’

The study concluded that in comparison to Chernobyl, the Fukushima accident ‘had a slightly higher 241Pu/239Pu atom ratio, but lower ratio of 240Pu/239Pu.’ Unit 3 was seen as the likely source for the high Pu detections.

[i] J. Zheng, K. Tagami, Y. Watanabe, S. Uchida, T. Aono, N. Ishii, S. Yoshida, Y. Kubota, S. Fuma and S. Ihara (8 March 2012 ) ‘Isotopic Evidence of Plutonium Release into the Environment from the Fukushima DNPP Accident,’ Scientific Reports, 2, http://www.nature.com/srep/2012/120308/srep00304/full/srep00304.html.

http://majiasblog.blogspot.fr/2017/07/blast-from-past-plutonium-contamination.html

August 3, 2017 Posted by | Fukushima 2017 | , , | Leave a comment

Possible safety regulation violations at Ibaraki Pref. nuclear facility led to accident: NRA

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In this photo provided by the JAEA, the stainless steel radioactive material container involved in the June 6, 2017 accident is seen soon after the plastic bags inside burst, exposing five workers to powdered plutonium and uranium oxides, at the Oarai Research & Development Center in Oarai, Ibaraki Prefecture.

Staff likely failed to follow safety regulations at a nuclear research facility in Ibaraki Prefecture where five workers were exposed to radioactive materials in June, a Nuclear Regulation Authority (NRA) inquiry has revealed.

While just after the accident the Japan Atomic Energy Agency (JAEA) stated that there was no way that such a serious incident could have been predicted, the NRA’s on-site investigation has revealed that, regardless of whether the accident could have been predicted, the facility staff were working without conducting proper safety procedures.

The accident occurred at the JAEA Oarai Research and Development Center in Oarai, Ibaraki Prefecture, at roughly 11:15 a.m. on June 6, when a worker opened a stainless steel container to inspect the powdered nuclear fuel materials within. The plastic bag inside the container ruptured, exposing the worker and four other staff to plutonium and other radioactive materials. The container had been sealed in 1991, and not opened once since.

“There was no way to know the state of the vessel’s contents, so the work was done extremely carefully,” the JAEA had initially explained. It had also stated that the workers had been aware that the plastic bag around the materials had degraded over the 26 years it was in storage. The JAEA had also been aware since January of a similar case at another facility where the plastic bag in a container had swelled up.

However, the recent inquiry found that the workers at the Ibaraki facility decided that the item on the inspection safety checklist stating “risk of explosion, rupture or dispersal” was non-applicable before beginning their task, which their supervisor also approved. Furthermore, though there were five sealed workstations in the room, the workers chose to open the container at a simple, unsealed workstation instead. No work plan had been put together prior to the task.

“If the workers had used a sealed workstation, it is clear that this accident could have been prevented,” lamented a JAEA representative.

Also, after the accident, it took three hours to set up a temporary decontamination tent for the effected workers. The survey found that the building where the incident occurred was not equipped with the materials necessary to construct the decontamination tent, and no drills for the setup had ever been carried out. In addition, a shower meant to wash away radioactive materials was also found to be broken.

“When handling plutonium, we cannot afford to make inexperienced or groundless decisions,” declared NRA Chairman Shunichi Tanaka at a regular meeting of the authority on July 5. “(The JAEA’s) safety culture is lacking.”

https://mainichi.jp/english/articles/20170707/p2a/00m/0na/013000c

 

July 9, 2017 Posted by | Japan | , , | 1 Comment

Rotten resin gas ‘most likely’ cause of Ibaraki nuclear accident

oarai, ibaraki.jpgThe fuel research building of the Japan Atomic Energy Agency’s Oarai Research and Development Center in Oarai, Ibaraki Prefecture, where the accident occurred June 6

 

The Japan Atomic Energy Agency (JAEA) now considers the most likely cause of last month’s nuclear contamination accident at its Oarai research center to be gas produced by decomposing resin containing plutonium and other radioactive substances.

The June 6 incident at the facility in Ibaraki Prefecture, northeast of Tokyo, exposed five workers to plutonium when they handled 26-year-old radioactive waste stored there.

Resin was used to stick the radioactive waste on an aluminum sheet and stored in a tightly sealed polyethylene container, which was wrapped in plastic bags and placed in a stainless steel container.

The accident occurred when the workers opened the steel container and were exposed to radioactive particles that seeped out of the polyethylene container in gas that ruptured the plastic coverings and escaped into the room they were in.

Decomposition of resin by a radioactive substance is considered as the most likely cause of the gas’s formation,” said Toshio Kodama, JAEA president, at a July 3 meeting with the science and technology ministry’s special investigation team that was set up to determine the cause of the accident.

JAEA found that the polyethylene container inside the plastic bags contained powdered plutonium set in pieces of epoxy resin.

The agency is looking at other possibilities, but now considers decomposition of the resin as the most likely cause.

On the same day, the National Institute of Radiological Sciences in Chiba announced that three of the five workers have been admitted to its facility for the third time to receive medication via an intravenous drip that speeds the excretion of radioactive substances from their bodies as urine.

The health of the five workers has not changed, according to NIRS.

http://www.asahi.com/ajw/articles/AJ201707040020.html

July 5, 2017 Posted by | Japan | , | Leave a comment

Plutonium in Workers’ Urine


The Asahi Shimbun is reporting that, contrary to the reassurances made a few days ago by the Japan Atomic Energy Agency (see here), workers at JAEA’s Oarai Research and Development Center, WERE internally contaminated by Plutonium:

Plutonium found in urine of 5 workers in Ibaraki accident. THE ASAHI SHIMBUN, June 20, 2017 http://www.asahi.com/ajw/articles/AJ201706200039.html

Minute amounts of plutonium have been detected in the urine samples of all five workers who were accidentally exposed to radioactive plutonium at Japan Atomic Energy Agency (JAEA)’s Oarai Research and Development Center in Oarai, Ibaraki Prefecture, on June 6…. While maintaining the level of exposure the five workers experienced “would not have immediate effect on their health for a few months,” Akashi said their internal exposure levels are “relatively high for cases occurring in Japan as far as I know.”… 

…In urine testing, NIRS said it can detect smaller amounts of plutonium as the measurement time is much longer, while the smallest radiation doses the dosimeter for lungs can detect is between 5,000 and 10,000 bequerels.

I shouldn’t be too critical of these oscillating reports given the US won’t even admit when its workers are contaminated with Plutonium, as the recent tunnel collapse at Hanford reminds us:

Tia Ghose. May 10, 2017. Hanford Disaster: What Happens to Someone Who’s Exposed to Plutonium? Live Science, https://www.livescience.com/59042-how-does-plutonium-damage-the-body.html

Workers at a nuclear-waste site in Washington state were recently told to hunker down in place after a tunnel in the nuclear finishing plant collapsed, news sources reported yesterday (May 9)…

The tunnel was part of the plutonium and uranium extraction facility (PUREX) said to be holding a lot of radioactive waste, including railway cars used to carry spent nuclear fuel rods, news agency AFP reported. At least some of the radioactive waste at the Hanford facility contains radioactive plutonium and uranium, according to the DOE, although at least some of it is also radioactive “sludge” composed of a mixture of radioactive substances. Right now, authorities have not revealed whether radioactive substances have been released or whether people have been exposed any of these contaminants

Governments don’t want to talk too much to the public about plutonium. Every dimension of knowledge about this element seems to be weaponized. Despite the desire for secrecy, plutonium always seems to be out of bounds, contaminating some people or environment, or perhaps all people, especially men’s testes (see here).

Plutonium’s astonishing level of chemical toxicity and atomic instability are fetishized by the atomic priesthood, but the priesthood cannot control their Frankensteinan creation, as these stories and ongoing atmospheric emissions at Fukushima Daiichi demonstrate:

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http://majiasblog.blogspot.fr/2017/06/plutonium-in-workers-urine.html

June 22, 2017 Posted by | Japan | , | Leave a comment

Plutonium in workers’ urine at Oarai Research and Development Center

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Traces of plutonium in workers’ urine

Doctors say extremely small quantities of radioactive substances have been detected in the urine of 5 workers who were accidentally exposed to the materials early this month at a research facility north of Tokyo.

The incident took place on June 6th at a facility of the Japan Atomic Energy Agency in Oarai Town, Ibaraki Prefecture. The workers were inspecting a nuclear fuel container when a bag inside suddenly burst, expelling radioactive powder.

The agency initially said as much as 22,000 becquerels of plutonium-239 were detected in the lungs of one of the workers. But they were discharged from hospital by Tuesday of last week after repeated examinations at the National Institute of Radiological Sciences detected no plutonium in their lungs.

On Monday, the institute said checks of the 5 workers’ urine later revealed extremely small amounts of plutonium and other radioactive materials.

It says the workers have so far suffered no damage to their health, but that they have reentered hospital to take medicines that will purge the plutonium from their bodies. They will take the drug for 5 days, after which doctors will decide if further medication is necessary.

An official related to the institute says the radioactive materials in the workers’ bodies are at levels that will not immediately affect their health.

Meanwhile, the Japan Atomic Energy Agency, which employs the 5 workers, on Monday submitted to the country’s nuclear regulator an interim report on how the accident unfolded.

The agency’s president, Toshio Kodama, told reporters that he apologizes to the public for the incident. Kodama added that his organization may have problems sensing and foreseeing risks.

Kodama said the agency has to work on organizational issues, including worker awareness.

The agency says it plans to conduct a detailed investigation into the cause of the accident. It says it will consider measures to prevent recurrences and report to the regulator.

https://www3.nhk.or.jp/nhkworld/en/news/20170619_27/

Tokyo, June 19 (Jiji Press)–Trace amounts of plutonium have been detected in the urine of all five workers exposed to radioactive materials at a nuclear research facility in eastern Japan earlier this month, a radiological research center treating them said Monday.
 The radioactive substances detected in the urine were plutonium-239, plutonium-238 and americium-241, the National Institute of Radiological Sciences, or NIRS, said.
The results showed that the workers at the Japan Atomic Energy Agency’s Oarai Research and Development Center in Ibaraki Prefecture, northeast of Tokyo,
suffered internal radiation exposure, the NIRS said.
The NIRS plans to continue examining the five workers for about a month to estimate levels of exposure.
   The exposure is unlikely to reach levels that cause symptoms, said Makoto Akashi, a senior official at the National Institutes for Quantum and Radiological Science and Technology, which oversees the NIRS.

http://jen.jiji.com/jc/eng?g=eco&k=2017061901238

Plutonium found in urine of 5 workers in Ibaraki accident

Minute amounts of plutonium have been detected in the urine samples of all five workers who were accidentally exposed to radioactive plutonium at Japan Atomic Energy Agency (JAEA)’s Oarai Research and Development Center in Oarai, Ibaraki Prefecture, on June 6.

The test results were announced June 19 at a news conference by the National Institute of Radiological Sciences (NIRS) within National Institutes for Quantum and Radiological Science and Technology (QST).

The revelation marks the latest twist in the changing assessment of severity of the health risks in the accident. Initially JAEA announced on June 7 that one of the five workers had suffered an internal exposure of 22,000 bequerels during an inspection at the nuclear energy research center. On June 9, JAEA said no plutonium was detected in any of the five workers’ lungs in further testing by NIRS.

Makoto Akashi, an executive of QST, said at the news conference the latest finding confirmed that the workers did “suffer an internal exposure.”

While maintaining the level of exposure the five workers experienced “would not have immediate effect on their health for a few months,” Akashi said their internal exposure levels are “relatively high for cases occurring in Japan as far as I know.”

He also added that long-term observation may be necessary depending on the level of internal exposure.

JAEA’s initial “internal exposure of 22,000 bequerels” assessment was hastily done on the night of the accident on June 6. The five workers were examined using a dosimeter that can detect small traces of X-rays emitted by plutonium particles inhaled into the lungs.

However, the next day, NIRS staff discovered that four of the workers did not have all the plutonium on their bodies completely removed. After thorough decontamination efforts, they were retested for plutonium in the lungs, which was “not detected.”

It is believed the initial assessment came back with a high reading, as the dosimeter also picked up the radiation from the plutonium residue on their bodies.

In urine testing, NIRS said it can detect smaller amounts of plutonium as the measurement time is much longer, while the smallest radiation doses the dosimeter for lungs can detect is between 5,000 and 10,000 bequerels.

The latest test result suggests the possibility that some plutonium particles inhaled into the workers’ lungs have been absorbed into the bloodstream, then discharged into the urine.

The five workers had been discharged and are in stable condition, but were readmitted to the institution for further treatment on June 18. They started receiving medication via intravenous drip injections to speed the excretion of radioactive substances in their bodies from June 19, according to NIRS.

It is the second time they have received this medication. NIRS confirmed the treatment’s effectiveness as the amount of plutonium in their urine increased after the first round of injections compared to the amount found prior to receiving the drug.

http://www.asahi.com/ajw/articles/AJ201706200039.html

June 22, 2017 Posted by | Japan | , | Leave a comment

Plutonium found in urine of 5 workers exposed to radiation

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TOKYO (Kyodo) — A small amount of plutonium was found in the urine of five workers exposed to radiation in an accident earlier this month at a nuclear research facility in Ibaraki Prefecture, a hospital operator said Monday.

The result shows that the five workers have suffered internal radiation exposure following the June 6 accident at the Japan Atomic Energy Agency’s Oarai Research & Development Center in the coastal town of Oarai.

They had been receiving medication to facilitate the discharge of radioactive materials from their bodies since the accident and will continue to do so, said the National Institutes for Quantum and Radiological Science and Technology, the operator of the hospital.

The five, although showing no signs of deterioration or notable change in their health, were hospitalized again from Sunday for the treatment.

In the accident, radioactive materials were released into the air in the room where the five were working when one opened a metal container holding plutonium and uranium powder samples and a plastic bag containing the samples inside suddenly ruptured.

Initially, the agency said up to 22,000 becquerels of plutonium-239 were found in the lungs of one of the five workers, while up to 5,600 to 14,000 becquerels of the radioactive substance were found in the lungs of three other workers. It said at the time that the four had suffered internal radiation exposure.

But the facility operator has since said a subsequent check by the National Institute of Radiological Sciences has found no plutonium in the lungs of any of the five workers. It has not ruled out the possibility that what was actually detected was radioactive substance left on the workers’ bodies after decontamination.

Also on Monday, JAEA President Toshio Kodama again apologized over the accident, saying at a press conference, “The agency as a whole had problems in the prediction of risks.”

He said he has no intention of resigning for now but will take “appropriate” responsibility depending on the cause of the accident.

The agency submitted a report compiling the causes of the accident and measures to be taken to prevent a recurrence to the Nuclear Regulation Authority, the state’s nuclear safety watchdog.

https://mainichi.jp/english/articles/20170619/p2g/00m/0dm/074000c

 

June 19, 2017 Posted by | Japan | , , | Leave a comment

Ibaraki nuclear facility where radioactive leak occurred was slack on safety

The facility handled plutonium but was unaware that a major accident could happen.

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As the facts surrounding the June 6 incident where five workers were exposed to radioactive materials following an accident at a nuclear research facility in Ibaraki Prefecture continue to emerge, it has become clear that the facility’s stance concerning safety management has been simply too soft — especially considering that it handles materials used for nuclear fuel.

The accident in question happened at around 11:15 a.m. on June 6 at the Japan Atomic Energy Agency (JAEA)’s Oarai Research & Development Center in the coastal town of Oarai in Ibaraki Prefecture. Uranium oxide and plutonium oxide powder that had been stored in double-wrapped plastic bags inside a sealed stainless steel container were accidentally released across the research laboratory after the bags suddenly burst, thereby exposing all five workers nearby to the radioactive compounds. Prior to the leak, one of the workers — a man in his 50s — was opening the container for inspection.

The check was carried out at an unsealed work station referred to as the “hood.” The radioactive materials had been stored at a pressure level lower than the surrounding area, in an attempt to prevent them from leaking. However, this proved to be ineffective. The compounds flew across the room, in powder form, immediately after the bags burst open.

In addition to the hood, there is also a “glove box” inside the facility, which can be used to handle dangerous materials. However, the facility has no specific rules determining which work station should be used for which purpose, and it has become normal practice at the site for workers to handle sealed nuclear materials — such as those kept inside containers — at the hood work station.

Apparently, during the check of the stainless steel container at the Oarai facility, there was no intention of opening the plastic bags, and therefore, it was judged that, “There was no danger of being exposed to radiation.”

However, the contents of the stainless steel container had not been checked once in 26 years. Commenting on this issue, an executive from the Nuclear Regulation Authority (NRA) has criticized the JAEA, stating, “How could they even be sure that the contents were kept sealed?” Meanwhile, an executive from the JAEA has said, “It was not anticipated that the plastic bags would burst. It seems that working at the hood work station may have been inappropriate.”

In addition, it has become clear that the five workers were not wearing full-face masks at the time of the accident. Instead, they were wearing masks that only covered their noses and mouths. Also, despite the fact there was a surveillance camera in the room, no footage was recorded, and no one was video monitoring the situation at the time of the accident.

Furthermore, an official from the NRA points out that, “It seems the facility was unaware that a major accident could happen.”

https://mainichi.jp/english/articles/20170613/p2a/00m/0na/016000c

June 13, 2017 Posted by | Japan | , | Leave a comment

Burst nuclear container scattered contaminants

Capture du 2017-06-10 20-04-56

 

The operator of a nuclear research facility north of Tokyo has detected contaminants scattered in the same room in which workers were exposed to radioactive substances from a nuclear fuel container.
Five workers were inspecting the container at the facility in Ibaraki Prefecture on Tuesday. A bag inside the canister suddenly burst, expelling radioactive powder.
The operator, Japan Atomic Energy Agency, says it has detected radioactive substances from 14 sections of the room’s floor. It says measurements reached a maximum of 55 becquerels per square centimeter.
Photos taken a day after the accident show black flecks scattered on the floor. The agency says they could be plutonium and uranium.
After the accident, the 5 workers were kept in the contaminated room for 3 hours. Agency officials said they did not anticipate an incident of this kind, and needed time to set up a tent outside the room to decontaminate the workers.
The agency earlier said one of the workers had 22,000 becquerels of radioactive substances in his lungs. This level of exposure can cause major damage to health. But it now says the actual figure could be lower. Officials say the testing device may have also measured contaminants on the surface of the man’s body.
The worker has been transferred to the National Institute of Radiological Sciences. The officials say plutonium was not detected in an initial test there.

https://www3.nhk.or.jp/nhkworld/en/news/20170610_04/

June 11, 2017 Posted by | Japan | , , , | Leave a comment

Increase in Cancer Risk for Japanese Workers Accidentally Exposed to Plutonium

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According to news reports, five workers were accidentally exposed to high levels of radiation at the Oarai nuclear research and development center in Tokai-mura, Japan on June 6th. The Japan Atomic Energy Agency, the operator of the facility, reported that five workers inhaled plutonium and americium that was released from a storage container that the workers had opened. The radioactive materials were contained in two plastic bags, but they had apparently ripped.

We wish to express our sympathy for the victims of this accident.

This incident is a reminder of the extremely hazardous nature of these materials, especially when they are inhaled, and illustrates why they require such stringent procedures when they are stored and processed.

According to the earliest reports, it was estimated that one worker had inhaled 22,000 becquerels (Bq) of plutonium-239, and 220 Bq of americium-241. (One becquerel of a radioactive substance undergoes one radioactive decay per second.) The others inhaled between 2,200 and 14,000 Bq of plutonium-239 and quantities of americium-241 similar to that of the first worker.

More recent reports have stated that the amount of plutonium inhaled by the most highly exposed worker is now estimated to be 360,000 Bq, and that the 22,000 Bq measurement in the lungs was made 10 hours after the event occurred. Apparently, the plutonium that remains in the body decreases rapidly during the first hours after exposure, as a fraction of the quantity initially inhaled is expelled through respiration. But there are large uncertainties.

The mass equivalent of 360,000 Bq of Pu-239 is about 150 micrograms. It is commonly heard that plutonium is so radiotoxic that inhaling only one microgram will cause cancer with essentially one hundred percent certainty. This is not far off the mark for certain isotopes of plutonium, like Pu-238, but Pu-239 decays more slowly, so it is less toxic per gram.  The actual level of harm also depends on a number of other factors. Estimating the health impacts of these exposures in the absence of more information is tricky, because those impacts depend on the exact composition of the radioactive materials, their chemical forms, and the sizes of the particles that were inhaled. Smaller particles become more deeply lodged in the lungs and are harder to clear by coughing. And more soluble compounds will dissolve more readily in the bloodstream and be transported from the lungs to other organs, resulting in exposure of more of the body to radiation. However, it is possible to make a rough estimate.

Using Department of Energy data, the inhalation of 360,000 Bq of Pu-239 would result in a whole-body radiation dose to an average adult over a 50-year period between 580 rem and nearly 4300 rem, depending on the solubility of the compounds inhaled. The material was most likely an oxide, which is relatively insoluble, corresponding to the lower bound of the estimate. But without further information on the material form, the best estimate would be around 1800 rem.

What is the health impact of such a dose? For isotopes such as plutonium-239 or americium-241, which emit relatively large, heavy charged particles known as alpha particles, there is a high likelihood that a dose of around 1000 rem will cause a fatal cancer. This is well below the radiation dose that the most highly exposed worker will receive over a 50-year period. This shows how costly a mistake can be when working with plutonium.

The workers are receiving chelation therapy to try to remove some plutonium from their bloodstream. However, the effectiveness of this therapy is limited at best, especially for insoluble forms, like oxides, that tend to be retained in the lungs.

The workers were exposed when they opened up an old storage can that held materials related to production of fuel from fast reactors. The plutonium facilities at Tokai-mura have been used to produce plutonium-uranium mixed-oxide (MOX) fuel for experimental test reactors, including the Joyo fast reactor, as well as the now-shutdown Monju fast reactor. Americium-241 was present as the result of the decay of the isotope plutonium-241.

I had the opportunity to tour some of these facilities about twenty years ago. MOX fuel fabrication at these facilities was primarily done in gloveboxes through manual means, and we were able to stand next to gloveboxes containing MOX pellets. The gloveboxes represented the only barrier between us and the plutonium they contained. In light of the incident this week, that is a sobering memory.

http://allthingsnuclear.org/elyman/cancer-risk-for-japanese-exposed-to-plutonium#.WTxxfxv-nM0.facebook

June 11, 2017 Posted by | Japan | , , , | Leave a comment

Nuclear workers were quarantined in plutonium-tainted room for three hours after accident: JAEA

n-nuclear-a-20170610-870x555The Oarai Research & Development Center in Ibaraki Prefecture is shown on Wednesday. The facility is overseen by the Japan Atomic Energy Agency.

 

The five workers exposed to airborne plutonium at the Oarai Research & Development Center in Ibaraki Prefecture were quarantined for about three hours in the room where the accident occurred, a Japan Atomic Energy Agency official said Friday.

Although this action was taken to prevent the plutonium and other radioactive contaminants from spreading to other parts of the nuclear research facility, it probably worsened their internal exposure as they breathed the tainted air.

Internal radiation exposure has been confirmed in four of the five men.

Education and science minister Hirokazu Matsuno said at a news conference Friday that a specially appointed team in the ministry would question JAEA President Toshio Kodama about Tuesday’s accident in the coastal town of Oarai.

The accident occurred inside an analysis room at the facility’s fuel research building around 11:15 a.m. Tuesday when a worker in his 50s opened a sealed metal container that had a plastic container of plutonium and uranium powder samples inside that was double-bagged in plastic. At some point, the bag ruptured, ejecting powder into the air.

JAEA says the tainted floor of the room is giving off 55 becquerels of radiation per square centimeter in the area in front of the apparatus — believed to be a fume hood — in which the container was placed before it was opened. The acceptable level is 4 becquerels, according to the Nuclear Regulation Authority.

The workers waited in the room for 3½ hours after reporting the accident. It was only at 2:44 p.m. that they started being checked for radioactive contamination, JAEA said.

When the accident occurred, the men were wearing masks that covered their noses and mouths, but the checks revealed radioactive material was in the nostrils of each one of them.

Subsequent lung checks showed that the man in his 50s had 22,000 becquerels worth of plutonium-239 in his system, compared with 5,600 to 14,000 becquerels in three of the other four. Four of the five were thus diagnosed with internal radiation exposure.

The metal container, which had not been opened once since it was sealed in 1991, was being checked on the instructions of the NRA. Experts evaluating the accident say it is possible that helium had accumulated in the bag over the years, raising the pressure in the container.

The NRA, the government’s nuclear watchdog, plans to look into the accident, including the manner in which the workers wore their masks.

The metal container in question had never been opened since it was sealed in 1991. The workers were checking the container based on an instruction from the nuclear watchdog. Experts have pointed to the possibility that helium gas had built up inside the bag over the years, raising the pressure inside the container.

http://www.japantimes.co.jp/news/2017/06/09/national/nuclear-workers-quarantined-plutonium-tainted-room-3-hours-accident-jaea/#.WTuQXDekLrf

June 11, 2017 Posted by | Japan | , , | Leave a comment

Ibaraki plutonium exposures baffle Japanese nuclear experts

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Experts probing the cause of the plutonium-inhalation accident involving five employees at a fuel research facility in Ibaraki Prefecture are trying to determine whether failures in safety equipment or procedures allowed the deadly powder to escape its container.

The accident might have been caused by the long-term buildup of helium emitted by the plutonium, one expert says.

The accident took place at around 11:15 a.m. Tuesday when five men from the Plutonium Fuel Research Facility at Oarai Research & Development Center were taking stock of a radioactive substance in an old storage container. This process usually involves placing the container into a special machine that adjusts the air pressure to prevent the material inside from being blown into the air.

Masked, gloved and donning other protective gear, a worker in his 50s along with a coworker standing by, removed the sealing bolts of a stainless steel container and opened the lid only to see a black powder burst forth.

The plastic bags were thick and we did not expect them to burst,” said an official at Japan Atomic Energy Agency, the facility’s operator. “I have no idea why (the plutonium powder) flew out of the container,” another said.

The powdery substance had originally been encased in a plastic container double-wrapped in plastic. It was then placed inside a stainless steel container sealed with six bolts. The container had not been opened since 1991, and held about 300 grams of uranium oxide and plutonium oxide that had been used in past experiments, JAEA officials said.

The container may have been filled with helium (which can be emitted by plutonium) from extended storage, and that may have increased the pressure inside it,” according to Kazuya Idemitsu, an expert on nuclear fuel engineering and a professor at the Graduate School of Engineering at Kyushu University.

Although masks were covering the workers’ noses and mouths, radioactive material was detected inside the noses of three of the exposed employees.

The agency said Wednesday that internal radiation exposure was detected in four of the five workers and that a fifth is suspected as well.

Up to 22,000 becquerels of plutonium were detected in the lungs of the worker in his 50s who opened the lid. Based on that figure, the agency estimates his body has likely has 360,000 becquerels of material inside it overall, they said Thursday.

Under current labor standards, that translates into 1.2 sieverts over a year, and perhaps a 12 sieverts over 50 years, the officials said.

The government allows designated nuclear workers to be exposed to a maximum of 0.05 sievert per year, or 0.1 sievert over five years.

This is an unusually high amount of radiation. We must carefully look into whether the workers took proper steps,” Nobuhiko Ban, an expert on radiological protection and a member of the Nuclear Regulation Authority, said at an NRA meeting Wednesday.

Plutonium decay can continuously damage cells in the body so it is imperative to make sure workers don’t inhale it, Ban acknowledged.

The main threat from internal plutonium exposure this is bone cancer.

There are very limited cases of treatment for internal exposure to plutonium in Japan,” Kazuhiko Maekawa, an expert on the subject, said.Gen Suzuki, an expert on radiation epidemiology and professor at the International University of Health and Welfare, said the amount of radiation in their bodies can vary based on the size and character of each particle of plutonium.


March 1997: Radioactive material leaks after a fire and explosion at the Ibaraki branch of now-defunct Power Reactor and Nuclear Fuel Development Corp., later absorbed by Japan Atomic Energy Agency. Thirty-seven employees were exposed.

September 1999: A self-sustaining chain reaction is triggered by the use of mixing buckets at uranium processing firm JCO Co. in the village of Tokai, Ibaraki Prefecture. The accident eventually kills two of three employees, after tainting more than 600 residents.

June 2006: A suspected case of plutonium inhalation occurs at Japan Nuclear Fuel’s reprocessing plant in the village of Rokkasho, Aomori Prefecture, but a check for internal exposure turns out negative.

July 2008: A worker at Global Nuclear Fuel Japan Co. is exposed to uranium in Yokosuka, Kanagawa Prefecture, followed by the exposure of four workers to a uranium-tainted liquid a month later.

March 2011: Three workers stepped in to a puddle during the meltdown crisis at the Fukushima No. 1 power plant, exposing two to high radiation.

May 2013: Thirty-four researchers at JAEA’s Japan Proton Accelerator Research Complex (J-PARC) in Tokai are exposed to an exotic soup of isotopes during an experiment.

http://www.japantimes.co.jp/news/2017/06/08/national/ibaraki-plutonium-exposures-baffle-japanese-nuclear-experts/#.WTuQ9jekLrd

June 11, 2017 Posted by | Japan | , , , , | Leave a comment

22,000 becquerels of plutonium-239 and 220 becquerels of americium-241 found in lungs of nuclear facility worker

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No one has inhaled this much plutonium’: 5 staff exposed to radiation in Japan lab accident

Japanese authorities are unsure about the medical prognosis for five staffers who inhaled toxic plutonium after mishandling it at the Oarai Research and Development Center outside Tokyo.

As far as I can remember, no one has inhaled plutonium at this level,” said Ishikawa Keiji, a security official at the Japan Atomic Energy Agency (JAEA) which oversees the lab, cited by the Jiji Press news agency.

The accident occurred at 11:15am on Tuesday in the analysis room of the facility dedicated to researching improved nuclear fuel for its fast reactors.

One of the five men opened a metallic cylinder where the fuel, a mixture of uranium and plutonium, is stored before and after experiments. In the process, the double plastic wrapping inside which the radioactive material is kept ripped, and the toxic substance burst into the air.

Shunichi Tanaka, chairman of the Nuclear Regulation Authority (NRA), which has frequently criticized the JAEA for the conditions at its facilities, said “workplace complacency” was possibly to blame.

The NRA said the workers had never experienced a similar plastic rip before, and as a result, did not feel the need to complete their research in a tightly sealed environment.

The researcher responsible for opening the box, described as a man in his 50s, had 22,000 becquerels of plutonium-239 detected in his lungs, and the other four between 2,200 and 14,000 becquerels.

Officials said the five staff have not yet complained of health problems with one assuring that “the amount is not enough to cause acute radiation damage,” according to the Japanese newspaper The Asahi Shimbun.

The longer-term predictions were less definitive, however.

Detection of 22,000 becquerels is a situation that cannot be easily brushed aside. It is no small amount, although it may not be life-threatening,” said Nobuhiko Ban, an NRA radiological protection specialist, quoted by The Asahi Shimbun. 

The five have been injected with a substance that speeds up the discharge of radioactive materials and remain under observation at the National Institutes for Quantum and Radiological Science and Technology.

The NRA has previously said that JEAA was “unfit” to operate an accident-plagued prototype reactor at Monju and has also faced accusations of poor handling of radioactive materials at another site.

But a use for Japan’s large plutonium stockpile must be found, and there are currently plans for utilizing MOX fuel – a mixture of plutonium and uranium, such as that involved in the latest accident – to power conventional reactors instead of the low-enriched uranium that they were designed for.

https://www.rt.com/news/391283-japan-nuclear-accident-plutonium/

No one has inhaled this much plutonium’: 5 staff exposed to radiation in Japan lab accident

Japanese authorities are unsure about the medical prognosis for five staffers who inhaled toxic plutonium after mishandling it at the Oarai Research and Development Center outside Tokyo.

As far as I can remember, no one has inhaled plutonium at this level,” said Ishikawa Keiji, a security official at the Japan Atomic Energy Agency (JAEA) which oversees the lab, cited by the Jiji Press news agency.

The accident occurred at 11:15am on Tuesday in the analysis room of the facility dedicated to researching improved nuclear fuel for its fast reactors.

One of the five men opened a metallic cylinder where the fuel, a mixture of uranium and plutonium, is stored before and after experiments. In the process, the double plastic wrapping inside which the radioactive material is kept ripped, and the toxic substance burst into the air.

Shunichi Tanaka, chairman of the Nuclear Regulation Authority (NRA), which has frequently criticized the JAEA for the conditions at its facilities, said “workplace complacency” was possibly to blame.

The NRA said the workers had never experienced a similar plastic rip before, and as a result, did not feel the need to complete their research in a tightly sealed environment.

The researcher responsible for opening the box, described as a man in his 50s, had 22,000 becquerels of plutonium-239 detected in his lungs, and the other four between 2,200 and 14,000 becquerels.

Officials said the five staff have not yet complained of health problems with one assuring that “the amount is not enough to cause acute radiation damage,” according to the Japanese newspaper The Asahi Shimbun.

The longer-term predictions were less definitive, however.

Detection of 22,000 becquerels is a situation that cannot be easily brushed aside. It is no small amount, although it may not be life-threatening,” said Nobuhiko Ban, an NRA radiological protection specialist, quoted by The Asahi Shimbun. 

The five have been injected with a substance that speeds up the discharge of radioactive materials and remain under observation at the National Institutes for Quantum and Radiological Science and Technology.

The NRA has previously said that JEAA was “unfit” to operate an accident-plagued prototype reactor at Monju and has also faced accusations of poor handling of radioactive materials at another site.

But a use for Japan’s large plutonium stockpile must be found, and there are currently plans for utilizing MOX fuel – a mixture of plutonium and uranium, such as that involved in the latest accident – to power conventional reactors instead of the low-enriched uranium that they were designed for.

https://www.rt.com/news/391283-japan-nuclear-accident-plutonium/

High level of radiation found in lungs of nuclear facility worker

OARAI, Ibaraki — A worker at a research and development (R&D) center here has been found to have a high level of radioactive material — up to 22,000 becquerels — in his lungs following exposure to radiation, the center said on June 7.

The discovery came after five workers at the Oarai Research & Development Center, which belongs to the Japan Atomic Energy Agency, were exposed to radioactive materials on June 6.

Radioactive materials are difficult to expunge from the human body, and it is thought that the level of internal exposure in this case will be 1.2 sieverts in one year, and 12 sieverts over 50 years.

The five workers have been taken to the National Institutes of Radiological Sciences in Chiba Prefecture, where they are undergoing examinations.

At a Nuclear Regulation Authority (NRA) meeting on June 7, a committee member said the workers’ situation is “not mild.”

According to organizations such as the NRA, one of the five workers was found to have up to 22,000 becquerels of plutonium-239 and 220 becquerels of americium-241 in his lungs. Two other workers were discovered to have 12 becquerels and 130 becquerels of americium-241 in their lungs, respectively. All five workers were administered medicine designed to reduce the radiation dose of the internal exposure.

The five workers were all wearing protective clothing and face masks at the time of the radiation exposure, the R&D center said. It is currently being investigated whether or not there were any problems at the time the incident happened.

Plutonium and americium are both harmful to human bodies as they emit alpha rays.

http://mainichi.jp/english/articles/20170607/p2a/00m/0na/018000c

Four workers exposed to radioactive materials at Ibaraki nuclear facility

Four workers suffered internal radiation exposure due to inhalation of a large amount of plutonium during an inspection at a nuclear research facility in Ibaraki Prefecture on Tuesday, the operator of the facility said Wednesday.

In the wake of what appears to be an unprecedented internal radiation exposure accident, the state’s nuclear safety regulator and local labor authorities inspected the scene to see if there were any flaws in safety management.

The accident occurred at the fuel research building of the Japan Atomic Energy Agency’s Oarai Research & Development Center when a bag covering a container for nuclear fuel materials, including powder samples of plutonium and uranium, tore during inspection on Tuesday.

Up to 22,000 becquerels of plutonium 239 were detected in the lungs of a male worker in his 50s. Up to 14,000 becquerels of radioactive materials were found in the three other workers, officials of the Japan Atomic Energy Agency said.

The Nuclear Regulation Authority said the worker with the higher reading has been exposed to an extreme amount of radiation and the situation is considered grave.

While none of the workers have complained of health problems so far, an official with the facility’s operator said it “cannot rule out the possibility of future health effects.”

The agency assumes that the amount of radiation exposure of the male worker in his 50s translates to up to 12 sieverts over 50 years, well above the legal limit set for workers who deal with radiation.

For its part, the labor office said that it estimates the man with the highest exposure to radiation has exceeded the annual limit of radiation exposure, which is 50 millisieverts a year and 100 millisieverts in five years.

Plutonium is known to emit alpha rays over a long period, damaging surrounding organs and tissues. If it is deposited into the lungs, it could increase the risk of developing cancer

The five workers have been transported to the National Institute of Radiological Sciences and given medication to help discharge radioactive materials from their bodies.

I saw such a (high) figure for the first time,” said Makoto Akashi, a senior official at the National Institutes for Quantum and Radiological Science and Technology, referring to the reading of 22,000 becquerels. The institute oversees the National Institute of Radiological Sciences.

It is very clear from a scientific viewpoint that the internal exposure to radiation would increase the risk of cancer (for the workers),” Akashi said.

I have never heard of such a large amount as a reading for internal exposure to radiation,” Shunichi Tanaka, who heads the NRA, told a separate news conference.

The workers wore masks but could have inhaled radioactive material from the small gaps between the masks and their faces.

Kunikazu Noguchi, an expert on radiological protection and associate professor at Nihon University, said it is hard to conclude the impact of the 22,000 becquerels, as the actual amount of radioactive substances he inhaled is still unknown.

It is possible, however, that the worker could have been exposed to more radioactive materials than the legally allowable maximum limit,” Noguchi said. He said it is necessary to get to the bottom of the incident, especially whether workers followed guidelines, as it is hard to imagine a plastic bag containing nuclear substances could tear in such a facility as the Oarai center.

http://www.japantimes.co.jp/news/2017/06/07/national/five-workers-exposed-radioactive-materials-ibaraki-nuclear-facility/#.WTkK8zekLrc

Worker at Ibaraki facility has up to 22,000 becquerels of plutonium in lungs

TOKYO – Five workers have suffered internal radiation exposure, with one found with up to 22,000 becquerels of plutonium in his lungs, following an inspection accident at a nuclear research facility in Ibaraki Prefecture on Tuesday, the operator of the facility said Wednesday.

In one of the worst accidents involving internal radiation exposure in Japan, up to 5,600 to 14,000 becquerels of plutonium 239 have been detected from the other three workers, the Japan Atomic Energy Agency said.

The accident occurred at the fuel research building of the agency’s Oarai Research & Development Center when a bag covering a container for nuclear fuel materials, including powder samples of plutonium and uranium, tore during inspection.

A labor standards inspection office in Ibaraki conducted an inspection Tuesday and Wednesday at the building, while the Nuclear Regulation Authority, the nuclear safety watchdog, also dispatched an inspector to the scene to check whether there were any violations of safety regulations.

The agency estimates that the amount of radiation exposure of the man with the highest level translates to up to 12 sieverts over 50 years.

The labor office believes that the man in his 50s has exceeded the annual limit of radiation exposure of 0.1 sievert in five years set for those who handle radioactive materials.

Plutonium is known to emit alpha rays for a long period, damaging surrounding organs and tissues. If it is deposited into the lungs, it could increase the risk of developing cancer.

The Japan Atomic Energy Agency has said the operation by the workers was carried out as usual.

Nuclear Regulation Authority Chairman Shunichi Tanaka said of the incident at a press conference, “Perhaps (the workers) have become too accustomed to plutonium. I urge careful handling.”

“As (a level for) internal radiation exposure it’s an amount unheard of,” he said.

“We shouldn’t downplay the situation,” said NRA Commissioner Nobuhiko Ban, a specialist in radiological protection.

While none of the workers has complained of health problems so far, an official of the facility operator said it “cannot rule out the possibility of future health effects.”

The five workers have been transported to the National Institute of Radiological Sciences and given medication to facilitate the discharge of radioactive materials from their bodies.

Since radioactive materials were found on hands and faces of four of the five workers, they have been decontaminated, said an official of the National Institutes for Quantum and Radiological Science and Technology, an umbrella organization of the National Institute of Radiological Sciences.

The workers wore masks to cover their mouths and noses but could have inhaled the radioactive materials from the small gaps between the masks and their faces.

The Japan Atomic Energy Agency has previously come under criticism for lacking safety awareness, following revelations of a massive number of equipment inspection failures at its Monju prototype fast-breeder nuclear reactor in Fukui Prefecture.

The Japanese government decided to decommission Monju last year after it has barely operated over the past two decades despite its envisioned key role in the country’s nuclear fuel recycling policy.

https://japantoday.com/category/national/5-workers-suffer-radiation-exposure-one-with-up-to-22-000-becquerels-of-plutonium-in-his-lungs#.WTh8DhaVAOw.facebook

 

 

June 9, 2017 Posted by | Japan | , , , , , | Leave a comment