Chronology and Press Reports of the Tokaimura Criticality
June 1, 1999
This survey of press information has not been analyzed for technical accuracy
For an index of images regarding the accident, go here.
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SEPTEMBER 30, 1999
note: all times reported in Japanese Standard Time, or 13 hours ahead of Eastern Daylight Time, except where noted 10:35 AM Various media sources report that a radiation leak was detected, its cause not immediately known. Police denied reports that a fire had broken out.
11:15 AM A Kyodo News Chronology (released on October 1) reports that the Japanese Science and Technology Agency received the first report on the accident from JCO.
11:33 AM The Kyodo News Chronology reports that the accident was reported to the Ibaraki Prefecture.
11:35 AM Asahi Shimbun. Monitoring for Gamma Rays begins.
12:41 PM The Kyodo News Chronology reports that police blocked roads near the plant and banned entry within a radius of 200 meters around the plant.
3:18 PM The Kyodo News Chronology reports that Tokaimura village authorities issued an evacuation advisory to 50 families living within a 350 meter radius of the plant.
3:35 PM Asahi Shimbun“Poor Preparation Delays Neutron Testing” . The Japan Atomic Energy Research Institute begins monitoring neutron levels at 14 locations around the facility, six hours after the accident.
4:00 PM IAEA Press Release. “Accident at the Tokaimura Fuel Conversion Plant.” IAEA learned of the accident. The IAEA Emergency Response Unit immediately made contact with Japanese authorities in order to closely follow the situation.
Japan Times. “Tokai Nuclear Accident Goes Critical; Remains out of Control.” Prefectural authorities in the adjacent town of Naka said the radiation level was rapidly increasing, based on observations of monitoring posts inside the town.
5:00 PM The Associated Press, “Radiation levels remain high after nuclear accident.” According to the Japan Atomic Energy Research Institute, 2-4 millisievert of radiation per hour or 10,000 to 20,000 times the normal level-was detected inside the processing facility as of 5 pm. The government’s Nuclear Safety Commission said there might have been a continuing “criticality,” as there continued to be high levels of radiation seven hours after the accident.
Sodium 24, a radioactive substance, was detected in the vomit of three of the victims.
The government decided to set up a task force headed by Science and Technology Agency chief Akito Arima to deal with the accident.
5:37 PM Citizen’s Nuclear Information Center, a Japanese nongovernmental organization, reports that initially, an atmospheric radiation count of 0.84 mSv/hour (10,000 times of the annual dose limit) was monitored, but the local government has announced that the radiation count is back to normal. The Science and Technology Agency announced that it was a criticality accident.
6:00 PM Citizen’s Nuclear Information Center reports that the head of Tokai villages stressed the following at a press conference: the atmospheric radiation count has not decreased around the site; there is a possibility that nuclear fission is still occurring at the moment; and the plant’s structure is intact.
7:00 PM Citizen’s Nuclear Information Center reports that the Tokaimura municipal officials said up to 4.5 millisievert of neutrons per hour was detected near the circumference of the plant shortly after 7:00 pm. Village officials also said Cesium-138 was detected near the plant.
The Kyodo News Chronology reports that the central government set up a crisis management task force headed by Prime Minister Keizo Obuchi.
IAEA Press Release. “Radiation Accident in Japan.” While the cause of the accident remains under investigation, it is known that it occurred when workers were transporting a mixture of liquid nitric acid containing 19 percent enriched uranium to a precipitation container. A “flash criticality” occurred.
At its highest point, the dose rate at the facility boundary was measured to be around 4 millisievert/hour.
The three seriously irradiated workers received a dose of more than 8 Sv.
8:00 PM Citizen’s Nuclear Information Center reports that the facility where the accident occurred is a commercial plant where enriched UF6 gas is converted to UO2 powder for further processing. The pellet fabrication is done in another plant nearby.
8:30 PM The Kyodo News Chronology reports that Ibaraki Governor Masaru Hashimoto issued an evacuation advisory to about 200,000 residents living within a 10 kilometer radius of the plant.
9:00 PM Citizen’s Nuclear Information Center reports that:
11:00 PM The Associated Press, “Nuke Accident serious, may be continuing, Nonaka says.” Chief Cabinet Secretary Hiromu Nonaka said, “There are concerns that the situation is continuing and is affecting a larger area than was believed earlier in the day.”
OCTOBER 1, 1999
Midnight The Associated Press. “Firms near accident close, ask workers to stay home.” Hitachi Ltd. and other major electronic manufacturers decided to shut down their factories near the site of the accident and asked their employees to stay home. They shut down a total of 12 plants and told more than 10,000 workers to stay home in the cities of Hitachinaka and Hitachi.
The Associated Press, “Local authorities told to prepare for evacuations.” The Fire Defense Agency instructed local authorities to be prepared for emergency transportation of residents in the region of a nuclear accident in Tokaimura, Ibaraki Prefecture. The agency’s emergency headquarters issued an instruction to the Ibaraki prefectural government to dispatch ambulances for possible transportation of residents who may be exposed to radiation. Tokaimura has only two ambulances.
Reuters, “Japan to seek U.S. military aid on accident.” Japan is considering seeking help from the U.S. military after the accident at a nuclear fuel processing plant. Kyodo news agency quoted officials as saying Japan lacked experience in dealing with this kind of accident and that the U.S. forces may have the necessary know-how.
Chief Cabinet Secretary Hiromu Nonaka said Japan’s Ground Self-Defense Force’s chemical warfare unit was ready to be deployed at the accident site but that it lacked relevant experience.
The Associated Press, “2 in critical condition after exposure to radiation.” Two of the three workers exposed to radiation are in extremely critical condition. The number of leukocytes of the three rose by two to four times the normal level. The ratio of lymphocytes in white blood corpuscles, which averages 40 percent among ordinary people also dropped below 10 percent and the figure for Ouchi and Shinohara is as low as 2 percent. The radiation dose for the two in critical condition number 8 to 10 sievert judging from their lymphocytes and overall condition. Judging from their skin, the two were exposed to radiation, which includes not only gamma rays but also alpha rays.
The Associated Press, “IAEA to dispatch inspector to Japan’s nuke plant.” The IAEA decided to dispatch inspectors to a uranium processing plant in Japan’s Ibaraki Prefecture, where the accident occurred. IAEA said the danger from the incident is “clearly above 2” on an IAEA scale ranging from zero to 7.
The Kyodo News Chronology reports that a senior JCO official admitted the company bypassed a required procedure.
1:00 AM The Associated Press, “Japan-Nuclear Accident.” A nuclear reaction apparently occurred while the workers there were processing the uranium into fuel for nuclear power plants. Radiation levels around the plant were 10,000 times higher than normal at one point, and about 10 times normal 1 1/4 miles from the accident.
Company officials said the accident was set off when the workers accidentally mixed too much uranium in a tank.
More than 310,000 people were ordered not to leave their homes and officials shut down schools and train service in the region.
The government asked US military forces in Japan for help, but were told that the US forces there were not equipped to handle such accidents.
The government task force composed of top ministers sent specialists to the area to monitor the radioactivity.
Reuters, “Japan nuclear accident now exposes 19” At least 19 people were exposed to radiation in an accident at a Japanese uranium processing plant, national broadcaster NHK said. The accident involved 16 kg (35 lbs.) of uranium, NHK quoted a plant worker as saying. Five of the injured were believed to be non-workers.
Mainichi Daily News, “3 Workers exposed to radiation in Tokai; residents evacuated.” Officials said that radiation levels had returned to normal by 12:30pm, almost exactly two hours after the fire that caused the leak broke out.
Makoto Ujihara, head of JCO’s Tokyo office, told a news conference that it was very likely that the accident had been the nation’s first critical nuclear mishap. Panel members on the task force blamed the cause of the accident on a number of factors. One member blamed the mishap on a blunder by workers. Other panel members called the accident a result of fundamental error.
JCO reported that the fire broke out in a container of “raw uranium.” Suggestions that the accident had been critical arose because the fire had a blue flame.
Soon after the blaze erupted, inordinately high levels of radiation were detected and an alarm sounded.
Police said that the three injured workers who fell sick had been transferring a “raw uranium” solution into a container when the fire broke out and they suddenly collapsed.
The Associated Press. “Obuchi admits government slow in acting on nuke accident.” Prime Minister Keizo Obuchi acknowledged that the government was slow in reacting to the accident. “We must pursue to the cause of the accident and go over it. But more than that right now, we must take all possible measures” to deal with the accident, the premier said.
The Associated Press. “Top MITI official sees need to review nuclear policy.” Japan’s top industry ministry official said that the government will be forced to reconsider its nuclear power policy following the radiation leak. The government will also have to consider establishing stricter requirements for safety standards in nuclear-related operations and conditions in giving licenses to fuel processing businesses. The top official added he will put priority on halting the nuclear fission reaction in the plant and reestablishing safety in the region.
The Associated Press. “Japan experiences worst nuclear accident ever.” According to the Japan Atomic Energy Research Institute (JAERI), 2-4 millisievert of neutrons per hour-equivalent to 10,000 to 20,000 times the normal level of radiation-was detected on the plant’s premises the evening of September 30.
JAERI said results of simple tests on the residents who have evacuated showed several of them might have been exposed to radiation. They are conducting further tests.
At the time of the accident, JCO officials said the workers were carrying out the procedure of dissolving solid uranium oxide in nitrate and transferring the solution to a precipitation tank to allow impurities to settle. Worker normally use up to 2.3 kg of uranium in each procedure to prevent a criticality accident. The amount to be put into the dissolver is controlled manually and by observing the concentration of uranium as the solution is prepared.
CNN, “Japanese nuclear accident injures workers.” Emergency crews were hampered in their efforts to stop the reaction because radiation levels in the area were too high.
Residents were warned to wash themselves thoroughly if they were touched by a light rain that officials said was carrying radiation from the air.
1:30 AM Japan Times. “Tokai Nuclear Accident Goes Critical; Remains out of Control.” The accident remains out of control.
According to Ibaraki police, the workers became ill while they were mixing a uranium compound with a nitric acid solution to produce fuel.
Tokai Municipal Government said that cesium 138, a chemical agent created by nuclear fission, was detected from the ground near the accident site.
By late afternoon on September 30, readings near the plant had climbed as high as 0.87 sievert an hour-about 4000 times the normal .0002 sievert.
2:00 AM CNN, “Thousands told to stay indoors after Japan nuclear accident.” Residents were warned to stay indoors as government officials feared a nuclear reaction was continuing at a damaged uranium reprocessing plant.
“We are now making every effort to stop the reaction,” said Toru Nakahara of the Japanese Science and Technology Agency.
Fourteen workers and five residents were treated for radiation exposure.
The reaction was set off when workers mixed too much uranium with nitric acid in a tank, officials from JCO said. The officials said 16 kg (35 lbs) instead of 2.4 kg (5 lbs) were used.
Officials said radiation levels were too high (4000 times higher than normal) to allow operators to get inside the plant.
Nakahara said that when workers are able to get inside the plant, they will attempt to drain water from the tank in the hope of stopping the nuclear reaction. Water, he explained, magnifies the radiation, making the nuclear reaction possible.
More than 300,000 people have been affected by the order to stay indoors.
US officials are working closely with the government of Japan on the response to the accident.
The Associated Press. “TEPCO vehicles with fission controller leave Fukus.” Vehicles left a Tokyo Electric Power Company (TEPCO) plant in Fukushima Prefecture carrying 400 kg of the metalloid element boron from its nuclear plant in Okuma and Futaba in Fukushima to the accident site about 100 km away. (Boron, used in control rods in nuclear reactors, can control and restrain a chain nuclear fission reaction.)
The Associated Press. “Japan experiences worst nuclear accident ever.” Five people working at a nearby construction site were confirmed to have been exposed and underwent tests.
The Associated Press. “Nuclear Power Policy to be maintained, agency chief” The head of Japan’s Agency for Natural Resources and Energy said that the agency will continue its policy on promoting nuclear power plants despite the accident. Hirofumi Kawano, director general of the Agency, said there is “no change in the importance of nuclear power plants insecuring stable energy supply and preserving the environment.” Kawano said the Agency will make “all-out efforts” to bring the situation at Tokaimura under full control.
2:35 - 4:16 AM Asahi Shimbun. “16 JCO workers toiled for hours to halt fission.” Efforts begin to remove the coolant water from pipes at the plant. 16 workers were involved in the operation. Two of the workers first went to the accident scene at 2:35 AM and took photographs of the valve for three minutes. The second group arrived at 3:01 AM and spent three minutes there to confirm that cooling pumps were working. The third group finally succeeded in opening the valve, but was not able to confirm that the water could be removed. The fourth group destroyed the valve at 4:16 AM but the water did not flow out of the pipe. The workers injected about 30 liters of boron chemicals, usually used on control rods in nuclear reactors, into the facility in an attempt to control and restrain the chain nuclear reaction.
3:00 AM Reuters. “Japan can handle nuclear accident-IAEA.” The IAEA said it was not involved in assessing the accident at the Japanese nuclear plant, saying that Japan was fully capable of handling the incident.
Hans Meyer, a spokesman for IAEA, said, “We have not been asked to send any safety mission to help them in connection (with this incident). Safety is a national responsibility. We only act on request and we have not been asked to come. Japan is a highly industrial country and they can manage this themselves.” Meyer dismissed a report that the danger from the accident was “clearly above 2” on the IAEA scale, saying they have not rated the incident.
Reuters. “Japan army sends chemical unit to nuclear site.” A chemical warfare unit of Japan’s Ground Self-Defense Force (GSDF) has been sent to the accident site. More than a dozen GSDF personnel including unit members, senior officials and two chemical-proof vehicles, were dispatched at around midnight.
Kyodo News Agency reports that “As the criticality is continuing, it is impossible to approach the accident site. Under the current conditions, activities are limited.”
4:00 AM Reuters. “Japan N-plant has 15,000 times normal radiation.” An Ibaraki Prefecture official stated, “As of late Thursday (30 September) night, 3.1 millisievert of neutrons per hour, or about 15,000 times the normal level of radiation, was detected two kilometers from the accident site.”
4:17 AM The Kyodo News Chronology reports that workers released the coolant water by destroying the coolant water pipes when the drainage valves malfunctioned.
Reuters. “U.S., Russia offer nuclear experts to help Japan.” U.S. Energy Secretary Bill Richardson announced that the United States and Russia have formed a team of nuclear experts to help Japan deal with the accident. Richardson said, “The Russians and the United States are ready to send a joint team.”
The Associated Press. “Japan-Nuclear Accident.” The Tokyo Electric Power Company rushed 880 pounds of sodium borate to the site, but authorities were trying to figure out how to get close enough to dump the powder on the radioactive holding tank and snuff the fission.
Two of the injured workers remained in critical condition and at least 34 other workers may have been contaminated. Five residents were also exposed to radiation.
State officials said they believe a gas containing alpha, beta and gamma radiation leaked from the plant.
5:30 AM IAEA Emergency Response Unit Memo to IAEA Directors. “Tokaimura bulletin no. 6” The criticality reaction appears to have ceased after around 5:30 AM. Dose rate monitoring points located outside of the site, in the downwind direction, were several times higher than normal. However, no confirmation can be given at this stage of any off-site release.
National Public Radio reports that a fire or explosion may have occurred at the site, which may have blown off the roof of the facility.
NPR also reports that workers are now removing the cooling water from the plant in order to prevent further critical incidents.
The Associated Press. “Number of people exposed to radiation rise to 24.” The number of people exposed to radioactivity at the uranium processing plant rose to 24 said the Science and Technology Agency.
The victims include three firefighters who were involved in the rescue of the three workers who were hospitalized.
6:00 AM The Associated Press. “Workers risk lives to stop chain reaction.” Thee ninth pair finally succeeded in blowing away the water with gas and some 10 minutes later, the radiation levels in the area started to decrease.
Of the 16 workers, six were exposed to more than 50 millisieverts-the maximum amount a worker engaged in radiation related jobs is permitted to receive in a year. Of the six, one was exposed to 91 millisieverts.
6:15 AM The Kyodo News Chronology reports that the neutron monitor at the plant site showed zero, signifying that a chain reaction had been halted.
6:30 AM The Associated Press. “Japan-Nuclear Accident.” At least 34 workers other than the injured were being examined for possible contamination.
Although no official government reading was released, Ibaraki state officials said radiation levels were about 10 times above normal 1 1/4 miles from the scene.
US Energy Secretary Richardson said the United States and Russia were prepared to send a joint team, but that he was awaiting a formal request for help from Japan.
7:00 AM IAEA Emergency Response Unit Memo to IAEA Directors. “Tokaimura bulletin no. 5” Gamma and neutron dose rates at the boundary of the facility were reported to be close to background levels. This was the result of the mitigation measure of draining the cooling water from the jacket around the container. In view of the now negligible neutron dose rates, it is being assumed by the regulatory body that the criticality event has been terminated.
9:00 AM The Kyodo News Chronology reports that workers began injecting boron chemicals into the facility to ensure that the nuclear chain reaction had been halted.
The Kyodo News Chronology reports that the government’s Nuclear Safety Commission said the nuclear chain reaction had been halted by the release of water coolant from pipes in the plant.
12:00 PM Japan declined an offer by the IAEA to immediately send experts to the accident site. The Japanese notified the agency of its decision saying the dispatch of IAEA experts is unneeded for now.
1:00 PM Reuters. “FOCUS-Japan nuclear reaction halted, govt. ashamed.” Late evening on September 30, officials told local residents that clothes worn during evening rain showers in the area should be washed and locally grown vegetables should not be harvested.
3:30 PM Reuters. “Japan seeks foreign assistance after nuke accident.” Japan has asked several foreign countries, including the United States and Russia, for information on how to deal with nuclear disasters. The Japanese Ministry has also asked Belgium, Britain, France, Germany and Sweden for relevant data in requests made through Japanese embassies in those countries.
4:00 PM IAEA Press ReleaseAccident at the Tokiamura Fuel Conversion Plant
The accident now appears more serious than originally thought. The number of workers at the plant exposed to radiation is now 39. The degree of exposure to the other workers and ten members of the public are being assessed.
Officials have learned that the criticality continued off and on for approximately 17 hours. A provisional rating for the accident using IAEA’s International Nuclear Event Scale, which runs from 0 to 7, rates at level 4.
The order to shelter the population residing within 10 km of the site has been lifted. In the meantime, Japanese authorities continue to measure the level of radioactivity in the vicinity of the site.
If requested by Japan, IAEA has offered to send an expert team immediately to the site and stands ready to provide assistance.
6:00 PM Reuters. “Russia considers nuclear cleanup kits for Japan.” Russia was considering a request for nuclear cleanup gear from Japan to help deal with the after-effects of the accident. The issue is being discussed at the Atomic Energy Ministry.
6:30 PM The Associated Press. “Nuclear Power industry frets over loss of trust.” Hiroji Ota, head of the Federation of Electric Power Companies, said, “Only one incident of negligence would help destroy all at once the confidence in the safety of nuclear plants that took a long time and great efforts of our workers to build.” He argued for the necessity of maintaining and newly building nuclear power plants, despite the accident.
Ota criticized the risk-management standards of the JCO Company and said the local publicity of the accident was too late and insufficient.
7:00 PM Reuters. “Japan nuclear mishap rating could be upgraded-IAEA.” IAEA spokesman said the “level four” rating assigned by the Japanese government to the accident was provisional and could only be confirmed once the off-site impact had been examined closely.
Reuters. “Japan experts say no danger of radiation spread.” Experts at Japan’s Kyoto University said the impact of the accident on the environment would be minimal.
Japanese officials warn nearby residents that well water could be contaminated by radiation, but said tap water from the central public water supply systems was safe to drink. The government also told local farmers not to ship vegetables to markets while experts were taking samples of soil and farm products to check for contamination.
8:00 PM Reuters. “FOCUS-Nuclear watchdog says deaths likely in Japan.” IAEA said of the three workers exposed to the high doses of radiation, “two of the three were so badly irradiated that their changes are very slim and the third is also in bad condition.” At least 55 people were exposed to radiation, including 45 workers, three firemen and seven people working at a nearby golf course.
The Associated Press. “Japan-Nuclear Accident.” Top government spokesman Hiromu Nonaka announced the lifting of an advisory for residents within six miles (10 km) of the plant to stay indoors, saying the radiation level in the area was back to normal. A 380-yard radius around the plant was still declared off-limits.
A testing center has been established at the center and people are asked to bring the clothing they were wearing at the time of the accident for inspection. Approximately 200 people who have been tested for radiation exposure at the center have come out clean, according to officials from the Japan Nuclear Cycle Development Institute, who conducted the examination. Authorities said the 80 or so people staying in the community center were unlikely to go home before Saturday morning, when they would be given health checks again.
Papers of Record
New York Times. “Japanese Fuel Plant Spews Radiation After Accident.” A1 Hans Meyer, a spokesman for the IAEA said that the uranium involved was from ore and was being cleaned in a chemical process.
Some American experts said that if, as reported, the tank was filled with uranium in the form of uranyl nitrate, this implied that the uranium had comes not from ore but from uranium being reprocessed after a prior use.
Washington Times. “Nuclear reaction controlled after radioactive spill.” A spokesman for the JCO Company acknowledged fault and said the accident was a “clear violation of in-house safety rules.” Police are investigating whether negligence was involved.
Asahi Shimbun. “Leakage deals blow to nuclear policy, industry.” JCO and its parent company, Sumitomo Metal Mining Co., admit the plant was not prepared to handle a critical mass accident. It also lacked mechanisms to automatically control the flow of nuclear fuel. The plant, which normally uses low concentrations of uranium of around 3-5 percent, failed to adopt safety measures to handle a critical mass accident triggered by the use of high concentration uranium. The concentration level at the time of the accident was about 18.8 percent.
OCTOBER 2, 1999
12:40 AM Reuters. “No health threat outside Japan from radiation-WHO” The World Health Organization said radiation that leaked from the plant posed no public health threat beyond the local population. The Geneva based U.N. health agency said it was reviewing the situation with the help of the IAEA. In a statement, WHO said “Although the fission reaction was sustained for several hours, the likely magnitude of fission product release does not constitute a public health concern outside Japanese territory and is unlikely to have any public health impact beyond the local population.”
1:30 AM IAEA.“Technical Briefing on the Radiation Accident in Japan.” According to the IAEA:
2:00 AM Reuters. “UK dismisses chance of Japan-style nuclear accident.” A spokesman for the British Nuclear Industry Forum, in discussing the difference between nuclear processing in Japan and in Britain, said that the Tokaimura facility was producing “the nuclear fuel component for a fast breeder reactor” and Britain doesn’t have one of those.
2:30 AM CNN.“Japan Takes Stock After Tokaimura Nuclear Accident” Japanese government admitted that it did not hold its first emergency meeting until 10 hours after the incident occurred. A Japanese Foreign Ministry spokesman blamed the delay on poor communication between the plant operators and the government.
Plant officials said that the plant was reprocessing uranium for use as fuel in an experimental breeder reactor.
Evening Media sources report that the Japanese government lifts evacuation order for the residents living within a 350-meter radius of the plant. According to Kyodo News, Chief Cabinet Secretary Hiromu Nonaka, confirmed safety in the area and said it was safe to consume farm produce in Ibaraki Prefecture.
Papers of Record New York Times. “Nuclear Peril is Over but Japanese Anger Isn’t.” Residents of Tokaimura, who were interviewed by phone while barricaded in their homes, expressed anger and disbelief that safety precautions could have been so lax and that the Government could have minimized the accident in the first crucial hours.
Japanese Minister of International Trade and Industry is worried the accident will cause psychological damage to the public. He stated, “I am worried that the unthinkable critical accident may throw cold water on the public trust in nuclear facilities.”
Nucnet. “Radiation levels at Nuclear Complex ‘Back to Normal’” Western European and U.S. nuclear fuel companies have said a comparable accident would not be possible in their fuel fabrication facilities. A spokesman for Foratom, the European atomic forum based in Brussels, added “European plants producing uranium fuel, irrespective of the enrichment level used (normally not exceeding 5%), are designed in such a way that they are criticality-proof.” A similar statement was issued on behalf of US nuclear fuel companies by the Nuclear Energy Institute.
OCTOBER 3, 1999
Papers of Record Asahi Shimbun. “Police Task force is set up to investigate allegations of negligence at the plant in Tokaimura, Ibaraki.” Ibaraki Prefectural police set up a task force to probe the accident. They intend to lay criminal charges against JCO Co. Ltd. and the company’s executives. They are focusing on the possibility of seeking criminal charges of professional negligence resulting in bodily injuries, violation of the law regulating nuclear reactors and related facilities.
Washington Post. “Atomic Plant in Japan Used Illegal Process.” For at least two years, the uranium processing plant has been using illegal procedures to handle uranium and other dangerous materials. The three workers injured in the accident were following a company manual when they poured the uranium mixture from a bucket into a settling tank, but this time the supervisor instructed the workers to use a 35-pound capacity tank instead of a smaller one. The workers were involved in processing 126 pounds of uranium for use in an experimental breeder reactor program.
Since work crews entered the building October 1st to remove the coolant water from pipes at the plant, radiation levels are still high, preventing workers from returning to the building. Some experts say it may be years before the radiation within the building drops to a safe level. Government officials said they may consider using robots to try to remove contaminated equipment.
New York Times. “Question for Japan: Why Was There So Little Planning For a Potential Nuclear Accident.” In a ‘News Analysis,’ the New York Times compiled a string of questions:
The Tokaimura uranium refining plant did not have any markings identifying the site as dangerous, its staff lacked proper protective shields, it had no alarm system, and it had never been equipped with a safety manual.
According to the New York Times, the Yomirui Daily reported that regulatory papers filed for the plant during construction did not include contingency plans or a discussion of the possible dangers of a fission reaction.
OCTOBER 4, 1999
The Associated Press. “6 exposed to radiation above annual limit.” Six of the eighteen workers who suffered radiation exposure while trying to remove coolant water from the plant’s pipes were exposed to a level above the annual limit set by law. According to internal documents of JCO, the worker who suffered the most radiation exposure among the 18 was exposed to about 91 millisieverts in three minutes. The five others who suffered radiation exposure above the limit were exposed to about 56 to 73 millisieverts each, while four others were exposed to more than 40 millisievert.
Normally, in accidents at nuclear power plants, it is possible to control the situation from a remote place, but the processing facility at JCO lacked a structure for handling such a criticality situation.
The Science and Technology Agency has said 67 people were exposed to radiation in the accident.
Japan Times. “JCO Chief Admits Workers were Poorly Trained.” The head of JCO Co.’s uranium processing plant, Kenzo Koshijima, admitted that the firm had never educated its workers regarding criticality or its effects and that portions of the procedures in a manual were skipped “for the sake of efficiency.”
Koshijima explained that his workers used stainless steel buckets to melt highly enriched uranium because using the melting tower–required by standard procedure–left residue that in turn raised questions as to the purity of the end product. He added, “It was also true that doing things manually was more effective in getting the job done at times.”
The Science and Technology Agency began carrying out emergency inspections on 20 nuclear fuel processing facilities nationwide. In conjunction with inspections of JCO’s offices, the agency will visit other facilities that process unsealed plutonium, spent nuclear fuel or uranium of 1 ton or more. Officials will check that operation manuals and records match actual procedures. They will also determine whether facilities are equipped with devices that prevent volatile substances from collecting in single location and if workers are educated on safety procedures in the event of a radiation release.
Over the next two weeks, the agency will visit four other uranium-processing plants, two spent nuclear fuel processing plants and 12 other facilities. Based on these visits, the agency will study whether further guidelines for building processing plants are necessary.
Trade chief Kaoru Yosano pledged that the Ministry of Trade and Industry would do its best to support local small and medium-sized enterprises that suffered from the radiation release through disaster relief loans.
Asahi Shimbun. “Nuclear worker wanted to finish early.” The supervisor at the plant in Tokaimura instructed two other workers to pour uranium exceeding the normal limit to speed up the process.
Police continue to investigate the manual’s procedural rules and are trying to establish whether superiors instructed the workers to conduct the dangerous work.
New York Times. “Atom Plant Cut Corners on Safety, Japan is Told.” One of the injured workers said he routinely used procedural shortcuts to speed up production.
Officials at JCO said the accident was a result of the “lack of sufficient expertise” of workers and have denied the allegation they told workers to employ production shortcuts to increase output. However, they have acknowledged that the plant has recently faced intense foreign competition.
BBC. “World: Asia-Pacific Nuclear Accident plant broke rules.” Hideki Motoki, operator of the JCO Company, admitted using illegal standards for uranium processing for the past four years. Among several known violations, the firm changed its procedures manual without government approval in order to speed up processing and allowed workers to transport uranium in stainless steel containers similar to buckets instead of relying on high-tech equipment. It has also been reported that the workers never received proper training.
Prime Minister Keizo Obuchi has heavily criticized the company highlighting the carelessness and poor training of workers, and the lack of proper emergency procedures.
Two of the workers most seriously injured are still awaiting bone marrow transplants. return to table of contents
OCTOBER 5, 1999
CNN. “Japan in full-scale nuclear accident probe.” Japanese investigators raided the Tokyo and Ibaraki offices of the JCO Company and confiscated bags full of papers. The questions of the investigation focus on whether the accident was caused by simple human error or whether there was a systematic violation of regulations. Other aspects of the investigation are focusing on whether the federal government showed lax supervision and could therefore be held responsible for failing to ensure the company had proper safety procedures to prevent the accident.
Science and Technology chief Akito Arima said authorities should tighten control over the nation’s nuclear facilities. In the meantime, he announced the government would “work on measures to prevent similar accidents from occurring in the future and incorporate them into Japan’s long-term nuclear program.”
Many Japanese residents expressed relief at being able to return home, but said they still feared the invisible threat of radiation and hoped those responsible would be punished.
New York Times. “Urgent Inspections Ordered For Japan’s Nuclear Plants.” Prime Minister Keizo Obuchi ordered emergency inspections at all of Japan’s nuclear-fuel treatment plants and reactors.
Reuters. “Obuchi to visit Tokaimura on Wednesday.” Prime Minister Obuchi will tour Tokaimura and visit the offices of JCO Company on October 6th in order to hear a full account of the cause of the accident from those in charge. The premier is also expected to explain to local government authorities and residents living near the plant the government’s efforts to investigate the accident and how it is dealing with the issue of compensation.
Reuters. “FOCUS-Japan to push nuke plans despite disaster.” Japan’s new government announced it would press ahead with the nation’s nuclear energy program despite the accident. The government still plans to build another 20 reactors by 2010.
JCO’s parent company, Sumitomo Metal Mining Co., said it was unaware of the day-to-day operations at the plant, but nonetheless acknowledged it bore a “social and moral responsibility” for the disaster.
The Associated Press. “Agency inspects 5 nuclear-related facilities.” The Science and Technology Agency continued on-the-spot inspections at seven nuclear power-related facilities. The survey centers on checking operation manuals for the prevention of criticality accidents, records of equipment and the nature of safety training for employees. Inspections are set to cover a total of 20 facilities nationwide.
The Associated Press. “Japan-Nuclear Accident.” Sumitomo Metal Mining Co. announced it would pay damages for the accident. Although it is too early to tell how much compensation claims would amount to, Kyodo News reveals that JCO was insured for up to $9.43 million under a nuclear accident insurance plan.
The Associated Press. “New Science Chief Seeks Review of Nuke Power Regulations.” Newly appointed director general of the Science and Technology Agency, Hirofumi Nakasone, announced the newly expanded coalition government would review existing nuclear power regulations. Nakasone said the Government will check for loopholes in the laws pertinent to the nation’s nuclear power industry, in addition to fully probing the causes of the Tokaimura accident.
Mainichi Daily News. “Tokai residents demand nuke compensation.” More than 20 lawyers and officials from JCO and Sumitomo Metal Mining Co. assembled at an office near JR Tokai Station, which opened recently to deal with complaints and queries from residents. According to JCO officials, they received nearly 80 claims within two hours of the office’s opening.
One day earlier, the Japan Atomic Energy Insurance Pool (JAEIP), a nuclear-energy underwriter organized by 43 insurance companies, decided to pay up to 1 billion yen to cover damages by the accident. If the amount of damage exceeds 1 billion yen, the company would be responsible to pay the rest, but the government could also cover the cost of compensation pending Diet approval.
Mainichi Daily News. “Majority say scrap nuclear energy.” In a Mainichi telephone poll conducted over the weekend, 70 percent of the public is against nuclear power. Only one in five said they favor the development of nuclear energy. Thirty-one percent called on the government to suspend the development of nuclear energy and to take effective safety measures.
Yomiuri Shimbun. “System to monitor radiation went unused.” The state-run system for predicting the spread of radioactive particles in the environment after a nuclear accident was not used. The System for Prediction of Environmental Emergency Dose Information (SPEEDI), developed by the Japan Atomic Energy Research Institute, was not used because “for budgetary reasons, the facility was not included among the facilities being monitored.”
According to the Science and Technology Agency, under the current system, SPEEDI only has topographical data on nuclear plants and nuclear fuel reprocessing plants, which are required to have disaster-prevention measures. In any event, the agency did not ask for SPEEDI data in order to predict dispersal patterns after the nuclear accident.
MSNBC. “Missteps focus of Japan nuke probe.” Firefighters called in to help injured workers say they were never warned of a potential release of radioactivity and went into a dangerous area without protective gear. Firefighters were among those exposed to radiation.
OCTOBER 6, 1999
Asahi Shimbun. “Resumption of nuke plant refused.” The Ibaraki Prefecture has decided not to give the Japan Nuclear Cycle Development Institute the go ahead to resume operations at a nuclear fuel reprocessing plant in the same village. JNC’s predecessor, Power Reactor and Nuclear Fuel Development Corp. (Donen) suspended operations of its nuclear fuel reprocessing plant in Tokaimura in March 1997, after a fire and explosion occurred. After installing stricter safety measures, Donen hoped to resume operations after approval from local governments. The vote was scheduled for 3 PM September 30, but was canceled due to the accident. Now, Tokaimura Mayor Tatsuya Murakami said: “The feelings of the people had been moving toward the acceptance of the resumption. But their ideas have changed 180 degrees. I canceled the safety declaration and have no intention to approve the resumption.”
Asahi Shimbun. “Police Search JCO office, plant.” A full-scale search for evidence that the JCO Company illegally altered uranium processing procedures began at 8:30 AM at the JCO head office in Tokyo. At the Tokai plant, investigators searched office facilities wearing radiation monitors and protective suits in case there were still dangerous levels of radiation in the plant.
Mainichi Daily News. “Fate of Tokai plant being mulled.” Resident demands forced the Ibaraki Prefectural Government to shut down the plant operated by JCO Company. The Prefectural Government stated it is up to JCO to clean up the contaminated site, but a company spokesman said there’s nothing that JCO can do until it learns the extent of the damage. The Tokai Municipal Government and local assembly members agree that JCO Co. should be held responsible and clean up the site in a timely manner. In the meantime, JCO has covered the contaminated area with bags containing a chemical that prevents radiation from escaping. It also checks to make sure that no holes or gaps appear in the sheet.
Reuters. “Japan Nuke Village Wants Action, Not Just Words” Prime Minister Keizo Obuchi renewed his pledge to tighten Japan’s nuclear energy safeguards during a visit to the Tokaimura plant. He tried to soothe residents fears about radiation exposure to the town’s local produce by eating a meal of locally grown vegetables and drinking local well water. The Science and Technology Agency has decided to revoke the business license of JCO Co. due to the “seriousness of the accident,” Kyodo News reported.
Japan Times. “Police raid Tokai plant; agency revokes license.” The Science and Technology Agency decided to revoke JCO’s business license after confirming that the processing plant bypassed government procedures. The action will be the nation’s first revocation of a nuclear plant’s business license. The measure will take place after radioactive substances are removed from the facility and the plant has been safety secured.
OCTOBER 7, 1999
Yomiuri Shimbun, “Agency to up N-accident rating to 5” The Science and Technology Agency plans to raise the rating of the nuclear accident that occurred in the Tokaimura uranium-processing plant to level 5 on the International Nuclear Event Scale (INES) of seven. The agency had provisionally rated the accident at level 4, which implies limited risk of radiological contamination outside the facility. However, after the agency discovered that JCO used an illegal manual for processing nuclear fuel and that workers were not following the manual, as well as finding that the operator had repeatedly neglected safety procedures, they decided to review the rating. A rating of level 5 on the INES implies considerable risk to areas outside the facility. STA will consult with outside experts to review the provisional rating before making an official decision, and then report to the IAEA.
Yomiuri Shimbun, “Research lab detects high neutron levels” Shortly after the Tokaimura criticality incident, neutron levels 10 to 100 times the normal level were detected at a JAERI laboratory about 2 km from the facility where the incident took place. According to the officials, at 10:37 a.m. on Sept. 30, two minutes after the incident, the neutron level detected by one of the two radiation monitors in the institute’s compound was registering 0.26 microsieverts per hour, well above normal levels, but it soon returned to normal. Officials said the lab initially ignored the unusual abnormal readings since the monitors occasionally detect abnormally high levels of radiation from other sources, such as electricity poles or strong sunlight. A study later confirmed that the neutrons were created by nuclear fission of uranium. The officials said that the neutron levels were too low to pose a health risk, and that topography could be the reason that the other monitor in the compound did not detect any neutrons. The institute is analyzing the data and studying how far the neutrons traveled, to determine the scope of the criticality incident, the officials said.
Reuters,“Japan Underestimated Nuke Exposure - Greenpeace” People living within 500 meters of the JCO uranium plant where the criticality event were exposed to radiation, according to Greenpeace. “We believe that the number of victims radiated from the incident is probably much higher than the official figure released by the government .. we believe up to several hundred” said one Greenpeace spokesman. Greenpeace also said that it had found evidence of radioactive fallout and high radiation levels on October 3 - 24 hours after the government had given the all clear - on a public road near the plant where the accident occurred.
Yomiuri Shimbun, “Panel to test residents for radiation” The Science and Technology Agency has decided to establish a committee of experts to examine the extent to which residents living near the accident site were exposed to radiation. The committee will include experts from the agency’s National Institute of Radiological Sciences and the Japan Atomic Energy Research Institute. The agency has previously revealed that 49 people, including JCO employees, were exposed to radiation in the accident. However, it plans to conduct a full-scale survey to examine the extent of the exposure and analyze its possible effects, as it is highly likely that more residents were exposed. The activities of residents who live in the vicinity of the facility immediately after the accident are not known, the officials said, adding that they “cannot deny the possibility of exposure to more people.” Officials said that the committee will: locate other possible victims of the accident; examine the types and amount of radiation and materials generated, by studying nuclear fission reaction records from the time of the accident; calculate how far radioactive materials were dispersed using wind direction data and other meteorological information from the time of the accident; and check the effects of radiation exposure on the health of those exposed.
Asahi Shimbun,“JCO officials admit lack of training” JCO Co. officials admitted that their employees had not been given any training on recognizing or dealing with radioactive material at critical mass. While JCO its employees to avoid causing a critical mass, it did not tell them what critical mass is or what happens when it is reached. One JCO executive said that when the three employees saw the “pale glow” that signifies criticality, they may not have been aware that critical mass had been achieved. Moreover, the JCO executives acknowledged that they had not been taught to identify the symptoms of people exposed to radiation. The plant continued to use “hidden” manuals on the uranium handling procedures for 10 years, even though supervisors knew the procedures described were illegal. The JCO plant has no system to warn of critical mass. Employees at the plant also were found to have been slow to seek safety. One of the three employees involved in the procedures that led to criticality told police he had no idea the work was so dangerous, police have said.
Asahi Shimbun also determined that in the course of work from September 29 through September 30, the amount of uranium being handled reached the point of critical mass on September 29, although it did not reach the criticality condition on that day. On September 29, the three workers poured four buckets of the uranium solution into a precipitation tank. At that time, 9.2 kilograms of uranium compound was involved, or 1.2 kilograms above the amount considered sufficient to result in criticality, although a criticality did not happen at the time. Criticality resulted on September 30, as the workers were pouring in the remaining three buckets of uranium compound.
Japan Times, “Police raid Tokai plant; agency revokes license” Police on Wednesday raided the headquarters of JCO Co. in Tokyo and its nuclear fuel processing plant in Tokai, Ibaraki Prefecture. Police are investigating the plant on suspicion of professional negligence and for evidence that the unit of Sumitomo Metal Mining Co. violated nuclear power plant regulations. It was the first raid on a firm suspected of professional negligence leading to a nuclear accident. The Science and Technology Agency the same day decided to revoke JCO’s business license after confirming that the processing plant bypassed government procedures. The action – the heaviest administrative penalty that can be taken – will be the nation’s first revocation of a nuclear plant’s business license. The measure will take place after radioactive substances are removed from the facility and the plant has been safely secured.
Yomiuri Shimbun, “JCO set to lose license” The Science and Technology Agency obtained facility operating records and copies of the unauthorized operations manual in an on-the-spot inspection. Documents showed that the JCO knowingly followed illegal procedures, according to the agency. The agency plans to inspect the contaminated building where the accident occurred, which has been closed since the accident, as early as next week. Inspectors will also assess damage done to the nuclear fuel-processing equipment, measure the amount of uranium solution left in the sedimentation tank and analyze nuclear-fission compounds. The agency also will check whether any radioactive substances could leak out of the facility.
Yomiuri Shimbun, “Police search JCO plant, office over N-accident” About 150 investigators entered the plant and the head office in Minato Ward, Tokyo, shortly after 8:30 AM to search for evidence in connection with allegations that the company violated a law regulating nuclear reactors and related facilities. The firm is also suspected of professional negligence resulting in injury. The investigators seized about 1,000 items, including the log detailing operations carried out at the building where the accident occurred. A JCO executive was quoted as telling police, “We approved the revision to the [operating] manual without [government] authorization. According to work records, staff had used the buckets illegally for seven or eight years.” As a result, police search warrants named JCO and JCO President Hiroharu Kitani as suspects in the violation of the law regulating nuclear reactors and related facilities. However, police did not name individuals suspected of professional negligence resulting in injury, since the extent to which the three plant workers were responsible for the accident has yet to be established.
Asahi Shimbun, “Nuke safety faces review” The Nuclear Safety Commission will review safety standards for uranium processing facilities and introduce measures to deal with any critical reaction accident at nuclear facilities. Among the new steps being considered are the installation of early-warning mechanisms and an automatic system to shut down critical reactions. Under current standards, facilities deemed unlikely to cause nuclear accidents are not required to adopt procedures to stop critical reactions. No mechanisms were in place to stop the critical reaction at the JCO facility last week where a chain reaction continued for about 20 hours. Plants that handle uranium in concentrations exceeding 5 percent are not required to have in place procedures for dealing with nuclear accidents as long as three conditions are in place: individual equipment is designed to avoid a state of criticality; the combined equipment structure is also designed to avoid a critical state; and measures are in place to prevent a critical state from being reached even if errors in procedures occur. The JCO plant was judged to have met the three conditions, and therefore did not have any equipment in place to stop the nuclear accident.
Yomiuri Shimbun, “Obuchi eager to see new law enacted”
Kyodo News reports that Prime Minister Keizo Obuchi said on October 6 that he would seek to enact new legislation to deal with nuclear disasters during the upcoming extraordinary Diet session. “We will consider further legal arrangements, including enacting a special law on nuclear disaster prevention,” Obuchi was quoted as saying. The prime minister said the government would also reconsider the existing Disaster Measures Basic Law so as to enable it to fully cope with accidents at nuclear-related facilities, government officials said. Obuchi told reporters that he instructed the heads of the International Trade and Industry Ministry and the Science and Technology Agency to submit a bill on nuclear-related disasters to the Diet during the extraordinary session expected to convene in early November. Upon Obuchi’s instruction, the agency later in the day set up a nuclear safety and disaster prevention task force within the agency with the cooperation of MITI to study new legislation.
Japan Times. “Cabinet Interview: Trust in nuclear energy Nakasone’s goal.” New Science and Technology Agency chief Hirofumi Nakasone says his first job is to regain the Japanese public’s trust in nuclear power. Nakasone said the nation’s nuclear industry must strictly educate plant workers about the potential dangers and importance of their jobs. Nakasone announced Government plans to establish a new law on nuclear disaster prevention and revise the existing law on nuclear regulations to improve safety standards at nuclear facilities. They agency will require nuclear fuel plants to undergo regular safety inspections and submit reports on their operations to the government. Such facilities will also be required to have a neutron-absorbing device installed to stop a nuclear fission chain reaction, as well as being highly airtight to prevent radiation from leaking outside.
Japan Times. “Agency reports Tokai damage but revelations continue.” The Science and Technology Agency informed the IAEA that the exterior of the roof of the uranium-processing plant is not damaged. The Agency said, “While there may be some cracks, since we have not been able to enter the site, the plant does not appear to be destroyed from the outside.” It added that it was not sure how much radiation may have escaped from the building.
PRNewswire. “U.S. Nuclear Energy Industry Has Initiated Review.” The Nuclear Energy Institute (NEI) is coordinating an U.S. industry review to examine the causes of and responses to the Tokaimura accident and to apply lessons learned from the review to U.S. facilities. The industry wide review will complement evaluations that U.S. nuclear fuel facilities typically perform in response to an event, such as occurred in Japan.
OCTOBER 8, 1999
Kyodo News. “U.S. expert arrives to help treat nuke accident victims” Dr. Robert Gale, an expert on the treatment of victims of radiation sickness, arrived in Japan to cooperate with Japanese doctors in the treatment of the three seriously injured workers from the accident. Gale is a professor at the University of California, Los Angeles.
Asahi Shimbun. “Greenpeace urges more health checks.” Greenpeace International officials conducted soil, plant and salt sample tests near the Tokaimura plant three days after the accident and found high levels of neutron radiation. Greenpeace also detected high levels of iodine 131 and iodine 133 around the plant, indicating that there had been radioactive fallout in the form of gas, rather than radioactive particles.
Washington Post. “Nuclear Spill May be Worse than Reported.” The Japanese Government has decided to expand its examination of people who may have been exposed to radiation near the plant. To date, 63 people have been identified as having been exposed.
The Associated Press. “Sumitomo Metal Mining to pull out of nuke fuel business.” Kyodo News reports that Sumitomo Metal Mining Company is considering pulling out of the nuclear fuel business following Japan’s nuclear accident. The move reflects the likelihood that the Science and Technology Agency will revoke JCO’s license to process nuclear fuel.
CNN. “Japan may upgrade nuclear accident after probe.” Science and Technology Agency Chief Hiromu Nakasone said Japan would accept the IAEA’s offer to help probe the cause of the accident in a bid to secure “transparency” and international trust in Japan’s nuclear program.
Kyodo News reports that IAEA will send three experts early next week to visit the plant and question officials from the municipal government and JCO Company. The IAEA team also plans to hear from the National Institute of Radiological Science in Chiba.
The Associated Press. “Nuclear accident site was shut down” The Science and Technology Agency revealed it had not inspected the plant for about five and a half years until April last year. Since April, an agency inspector inspected the plant about once a month, although only twice inside the building where the accident occurred. Both times the building was not in operation. The 26-member Nuclear Safety Commission investigative committee aims to compile a proposal to prevent the recurrence of a similar accident by the end of this year. JCO Company announced that coolant water removed from the building during the hours after the accident had drained into the soil. The leak was caused by a broken outdoor pipe. JCO is currently analyzing soil samples to check for possible contamination.
The Associated Press. “Processing plant closed for 14 months before accident.” The three workers most seriously injured in the criticality accident had not worked in the processing plant where the accident occurred for more than year because it was closed. The building was not in operation from June last year through to early September this year, during which time the three workers were tasked with the disposal of waste in a different building.
The Associated Press. “Japan-Nuclear Accident” Toshiki Takagi, president of the Metal Mining Agency and Moriki Aoyagi, president of Sumitomo Metal Mining Company, have both resigned. Takagi served as president of JCO Company from June 1995 until June this year, Kyodo News reported.