Possible safety regulation violations at Ibaraki Pref. nuclear facility led to accident: NRA
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
Rotten resin gas ‘most likely’ cause of Ibaraki nuclear accident
The 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.
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:
http://majiasblog.blogspot.fr/2017/06/plutonium-in-workers-urine.html
Plutonium in workers’ urine at Oarai Research and Development Center
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.
Plutonium found in urine of 5 workers exposed to radiation
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
Ibaraki nuclear facility where radioactive leak occurred was slack on safety
The facility handled plutonium but was unaware that a major accident could happen.
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
Burst nuclear container scattered contaminants
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.
Increase in Cancer Risk for Japanese Workers Accidentally Exposed to Plutonium
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.
Nuclear workers were quarantined in plutonium-tainted room for three hours after accident: JAEA
The 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.
Ibaraki plutonium exposures baffle Japanese nuclear experts
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
Ibaraki nuclear research facility under scrutiny after accident; gas suspected in rupture
OARAI, Ibaraki — A nuclear research facility here has come under scrutiny after workers were exposed to radiation while checking radioactive materials that had remained in storage for 26 years.
One of the workers exposed to radiation in the accident at the Oarai Research & Development Center of the Japan Atomic Energy Agency (JAEA) on June 6, identified as a male in his 50s, was found with up to 22,000 becquerels of plutonium-239 in his lungs, raising fears he could develop cancer or suffer other health problems.
According to the JAEA, the total level of radioactive materials that entered the man’s blood, bones, organs and other parts of his body was estimated at 360,000 becquerels, based on the amount detected in his lungs.
Problems with safety management at the agency had already been pointed out, and focus is likely to turn toward whether the work at the time of the accident was appropriate.
The agency said that when the worker opened the bolted lid of a steel container during a check, the plastic bag inside ruptured, scattering dust containing uranium and plutonium. Two other workers were next to the worker at the time, assisting in the check.
The some 300 grams of dust was produced when fuel was created for the onsite Joyo experimental fast reactor, which first reached criticality in 1977. It had been placed in a polyethylene container, enclosed in two plastic bags, and then placed in a steel container, where it had been stored since 1991. There were no records to show that the container had been opened before, officials said.
The latest check was being conducted after the Nuclear Regulation Authority had pointed out problems with the management of fuel at another JAEA facility. The JAEA had planned to check 21 steel containers containing uranium and plutonium dust. The accident on June 6 occurred during a check of the first of these containers.
Why did the plastic bag rupture? Kazuya Idemitsu, a professor in the Laboratory of Energy Materials Science at Kyushu University, commented, “Over time, the atomic nuclei of uranium, plutonium and other such substances break down, releasing helium nuclei (alpha rays). When stored over a long time, helium gas would build up, and it’s possible that the pressure inside the container rose, resulting in the rupture.”
Sources close to the JAEA also acknowledged this possibility, with one commenting, “It may not have been a good idea to use a polyethylene container, which had a possibility of rupturing, for storage over a long period.”
On June 7, the Ibaraki prefectural and Oarai municipal governments conducted an on-site inspection of the Oarai Research & Development Center under a nuclear safety agreement. Seventeen officials viewed the inside of the analysis room where the accident occurred through a monitor, and examined the concentration of radioactive materials in expelled air.
Masaaki Kondo, a safety coordinator at the prefectural nuclear power safety division, commented, “We confirmed that the damage did not spread.” The Mito Labor Standards Inspection Office and prefectural police are investigating the cause of the accident and whether the work that led to it was appropriate.
https://mainichi.jp/english/articles/20170608/p2a/00m/0na/018000c
22,000 becquerels of plutonium-239 and 220 becquerels of americium-241 found in lungs of nuclear facility worker
‘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.
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.
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