CRITICALITY
ACCIDENT AT A URANIUM CONVERSION FACILITY
AT TOKAI-MURA, JAPAN
Second Death from JCO Criticality Accident
Reported by the CNIC (Citizens' Nuclear Information Center), Tokyo,
27 April 2000
Japan not to upgrade worst nuclear accident
The Japanese government decided to maintain the level 4 rating of the
Tokai-mura accident
Reuters Japan, April 26, 2000
Japan Nuclear Co. Chief To Resign
New York Times, 15 February 2000
By The Associated Press
Nuclear guideline draft defines what emergency is
Japan Times, 9 February 2000
Asahi Glass, Mitsubishi Corp. to acquire BNFL subsidiary
Tokyo, February 7, 2000
Nuclear leak worse than first feared - More than
400 were exposed to radiation in Japan
The Guardian, wednesday February 2, 2000
By Jonathan Watts in Tokyo
THE "POST-ACCIDENT" MEASURES AND ISSUES
STA and several groups of independant scientists have carried out sampling
around the JCO Tokai plant, mainly in the 350 m area zone. Radioactive
fallout of cesium-137, iodine-131, strontium-91 and sodium-24 have been
(extensively for sodium-24) confirmed.
The STA inspection of the JCO plant (which is legally
prescribed) on 3 october 1999 was the very first one in 10 years to
be carried out. It was also revealed that STA had conducted no site
inspection either at Tokai Reprocessing Plant (operated by JNC) or at
Rokkasho-mura Enrichment Plant (operated by JNFL) over six years. STA
claims they were too busy.
On 4 October 1999, it is announced that various samples of a common
local herb had been collected by citizens in the area on 2 October 1999,
measured by the Research Reactor Institute of Kyoto University, were
found contaminated with 23 to 54 Bq/kg Iodine-131.
The following is an overview of fission products detected within 3
km of the accident site. The figures were taken from newspapers and
TV reports, and have been compiled by CNIC. (Citizens' Nuclear Information
Center, Tokyo:
- strontium-91 : 0.021 Bq/m3 in air, 900 m southeast of the site
- strontium-91 (krypton-91) : unknown amount, location not specified
- iodine-131 : 54.7 Bq/kg from mugwort leaves, 100 m from the site
- iodine-133 (krypton-91) : unreported amount, 100 m from the site
- cesium-137 : unreported amount, 7 locations
- sodium-24 : 64 Bq/kg, 300 m west from the site
- sodium-24 : 1.7 Bq/kg, 3 km west from the site
- xenon-139 : from the vomit of the exposed workers
- krypton-91 : from the vomit of the exposed workers
The environmental group Greenpeace investigated materials from around
the site -- including soil from around the accident site as well as
salt (which is a neutron flow indicator) from the homes of local residents
-- and concluded the government lifted its evacuation advisory too soon.
According to Greenpeace, neutron radiation seems to have irradiated
the environment at least 500 meters from the accident site, which would
have reached a major nearby street and more than 170 homes as well as
a golf course and farmland.
The mayor and the Governor of Ibaraki Prefecture jointly met the Prime
Minister Obuchi on Monday (4 Oct). They firmly requested the suspension
of JCO's operations, and also stated that new legislation to guarantee
safety in nuclear plants should be introduced.
In the mean time the mayor of Tokai-mura issued an order of total suspension
of the operation of JCO Tokai plant (all the work inside its Tokai facility)
on the basis of the Safety Agreement between the company and the village
administration. This is the first time in Japan in which a local government
made use of this sanction power based on the nuclear safety agreement
with a plant operator. It was also decided that the Tokai nuclear fuel
reprocessing plant, of which the operation has been suspended since
the March 1997 explosion and fire, would not restart for the time being.
The reporcessing plant was about to restart. Its operator is Japan Nuclear
Fuel Cycle Development Institute (JNC), former PNC.
On 6 October 1999, according to Kyodo News Agency, the Science and
Technology Agency (STA) has decided to revoke the business license of
JCO Co due to the "seriousness of the accident".
According to Reuters, on 6 October 1999, a police
spokesman said that about 200 investigators raided JCO's headquarters
in Tokyo and its office in Tokai-mura, searching for causes and responsibilities
for the accident. It has been reported that STA and the Ibaraki Prefecture
Police are involved in the investigations.
Kyodo quoted government sources as saying that the authorities have
confirmed during their investigations that JCO had changed the government-approved
procedure manual and used the illegal one as "standard procedure." JCO
officials have admitted the firm illegally revised a government-approved
manual to allow workers to use buckets instead of a pump to transfer
a uranium solution to a tank. It has been revealed that the three JCO
workers, who were hospitalized due to massive radiation exposure, had
not been wearing their film badges to measure radiation dose. This is
another serious violation of the safety regulations.
The responsability of the Tokai local government is also put into question
since it did not conduct a nuclear emergency exercise for the last eight
years.
According to news reports, at the time of the accident,
there was not even any hot line between the prefectural government and
Tokaimura's town hall. Tokai officials had to rely on busy public telephone
lines when they tried to obtain radiation monitoring data from the prefectural
authorities after the accident.
The Government's emergency response headquarter has been resolved,
and now a Nuclear Accident Investigation Committee is to be set up.
The PM's office ordered an ad hoc inspection in all nuclear facilities,
including power plants, all over Japan.
A number of public meetings and protest actions are being organized
all over the country by NGOs, trade unions and concerned citizens.
The Tokai-mura uranium was of French military origin :
The uranium which originated the criticality accident at Tokaimura on
30 septembre was of French origin, confirmed JCO Co spokesman,
Norimichi Mori, to the French daily Le Monde. French sources indicated
that the 18,8% enriched uranium was exported in december 1997. The 420
kg of uranium had been enriched by COGEMA in its military enrichment
plant in Pierrelatte (shut down in 1996). The deal had been organized
by the German nuclear fuel broker NUKEM. COGEMA stressed directly after
the accident that it had no agreement with JCO Co. In fact COGEMA's
client is JNC Co, operator of the Joyo experimental fast breeder reactor,
which subcontracted the conversion work to JCO.
According to insider reports, STA officials are going to rank the Tokai
accident at Level 5 instead of Level 4 on the International Nuclear
Event Scale (INES), in other words as severe as Three Mile Island accident
1979.
"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,"
the STA told the IAEA. It added that it was not sure how much radiation
may have escaped from the building.
The approach of spokesmen for the companies involved seemed similarly
focused on the need to provide swift reassurance and emphasised the
culpable role of workers without examining that of managers, even those
on the spot, let alone those higher up in the JCO company and its parent
corporation, Sumitomo Metal Mining.
The insurance program designed to cover damage from nuclear accidents
is not likely to compensate people for lost sales of agricultural products
because of the Tokaimura nuclear accident, sources said on thursday
4 october. Sales are expected to decline in Tokaimura and neighboring
municipalities in Ibaraki Prefecture. Nor is the insurance program likely
to cover the entire cost of other losses stemming from the nation's
first accident involving nuclear criticality. These include losses related
to the suspension of railroad services and temporary closure of private
firms. The insurance system makes it mandatory for operators of nuclear
facilities to buy insurance against possible accidents. Further, it
allows the use of taxpayers' money--subject to Diet approval--to pay
compensation if the responsible operator is not capable of paying for
all damages, reported the daily Asahi Shimbun.
CNIC revised its estimation of the quantity of U-235 that underwent
fission to "up to several tens of milligram of U-235". The Japanese
Government's Nuclear Safety Commission (NSC), according to the daily
Asahi, claims that the figure would be in the order of 0.001 mg (10E-6
grams).
NSC confirmed in an official report to the Government that the criticality
in the Tokai accident continued for 17.5 hours; the judgement is based
on neutron dose monitoring by different institutions.
The number of exposed people continues to increase,
and reached 63 as of 9 October 1999.
Sumitomo Metal Mining company, of which JCO is a 100% subsidiary, now
intends to totally withdraw from the nuclear fuel business. This means
that quite a few of the Japanese nuclear reactors will have to find
overseas suppliers for nuclear fuel assemblies (conventional uranium
fuel). For instance, Kyushu Electric Power Company depends for 70% on
JCO uranium fuel, and is severely affected by the suspension (and permanent
shut down, which is now likely) of JCO operations.
The European Parliament voted for a total review
of " all the nuclear facilities worlwide " by the IAEA. They require
controls and check-up at the Tokaimura plant and ask the japanese officials
for revised safety procedures. Hirofumi Nakasone, the new head of the
Science and Technology Agency (STA) accepted IAEA experts to come to
" increase transparency and recover international confidence."
On 14 October 1999, the visit of three IAEA experts in Japan comes
a day after the Japanese Government admitted a ventilator at the plant
had been mistakenly left operating for 12 days, allowing radioactive
particles to leak into the atmosphere. The ventilator was only turned
off on Monday 11 October 1999, three days after high levels of the radioactive
substance iodine 131 were detected around the plant. Radiation levels
at the accident site at Tokaimura are still dangerously high, so it
is unclear how close the IAEA team will get.
Experts and scientists at a symposium held at Kyoto Seika University
on 4 October 1999, said the government should be accountable for the
nuclear accident at the uranium-processing plant in Tokai, Ibaraki Prefecture.
They also expressed concern that the company as well as the government
might be withholding information or releasing incorrect information
about the nation's worst nuclear disaster. Seika University President
Hajime Nakao said the fact that the country is continuing with plans
to put the Joyo fast-breeder reactor back online makes him think that
the government wants the ability to build nuclear arms.
As part of the reorganization of central government ministries and
agencies, which will begin in 2001, the Nuclear Safety Commission (NSC)
will operate under a newly created Cabinet office, with enhanced independence
- being an advisory body, the NSC has no licensing authority - as will
be the case with the Nuclear Energy Commission. The two commissions
now belong to the Prime Minister's Office.
At a press conference on 15 october, JCO admitted
that a " limited amount " (20 Bq/m3, twice the allowed quantity)
of radioactive iodine-131 had been released into the atmosphere after
the accident via the ventilation system of the building in which the
criticality accident occurred. Prefecture and STA knew about the iodine
release, but they took no measures considering the escaping quantity
of radioactivity would be negligible. Concentrations of 0.04 Bq/m3 of
I-131 were detected 50 m southwest of the building (the monitoring point
is still within the JCO premises.)
One member of the first team who approached the building to take photographs
of the pipe systems they were going to work on, according to a JCO statement,
was initially dosed with 20 mSv. Now it is revealed that the workers
wore 2-digit type neutron recorders (the meter is reset to "00" when
the count is over 99). The "20 mSv" actually were 120 mSv (neutron plus
gamma, mostly consisting of neutron dose.) The fact was reported by
STA on 15 october 1999 to the accident investigation unit of NSC. In
the same report, STA confirmed that the number of the exposed persons
now reached 69. This figure does NOT include the general public who
had stayed very close to the plant for over 5 hours in neutron shower
before they were evacuated. Dr Komei Hosokawa of Saga-University estimates
that some 100 to 150 people were significantly exposed to neutron radiation.
Back
Japan not to upgrade
worst nuclear accident
The Japanese government decided to maintain the level 4 rating of
the Tokai-mura accident
Reuters Japan, April 26, 2000
[posted 27 April 2000]
TOKYO - Japan has decided against upgrading its first fatal nuclear
plant accident, sticking to a preliminary rating of "level four" rather
than opting for the more serious level five.
A level five was assigned to the 1979 accident at Three Mile Island
in the United States.
"We decided on level four for the final rating," a Science and Technology
Agency official said on Tuesday.
The government had previously said the accident last September at
a uranium processing plant plant in Tokai, 140 km (90 miles) northeast
of Tokyo, might be upgraded to level five.
It occurred when workers put nearly eight times the proper amount of
condensed uranium into a mixing tank, triggering a nuclear chain reaction.
Level four on the International Atomic Energy Agency's zero-to-seven
International Nuclear Event Scale indicates the possibility of a fatal
radiation leak at the accident site but no significant risk outside
the plant, the official said.
The Soviet Union's Chernobyl accident in 1986, rated a level seven,
was the worst nuclear power accident on record.
Tokyo University Hospital said on Monday that a 40-year-old worker
exposed to heavy doses of radiation in the Tokai incident had slipped
into serious condition.
"The patient's prognosis is uncertain after he suffered multiple organ
failure," the hospital said in a statement. Another Tokai worker died
as a result of the accident late last year, while a third who suffered
heavy radiation exposure recovered and was released from hospital in
December.
A total of 439 workers and residents were exposed to radiation as
a result of the accident.
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Second Death from JCO Criticality
Accident
Reported by the CNIC (Citizens' Nuclear Information Center), Tokyo,
27 April 2000
[posted 27 April 2000]
Mr. Masato Shinohara who was exposed to a lethal dose of radiation
on 30 September, 1999 at JCO Co., the site of the criticality accident,
died in the early morning of 27 April, 2000. According to the Science
and Technology Agency's estimation, he was exposed to 6 - 10 gray-equivalent
of radiation.
Back
Japan Nuclear Co. Chief
To Resign
New York Times, 15 February 2000
By The Associated Press
TOKYO (AP) -- A top executive at a company closely linked to Japan's
worst nuclear accident said Tuesday [15-02-2000] that he would resign
to take responsibility for what happened.
Moriki Aoyagi, the president of Sumitomo Metal Mining Co., said he
felt "socially and morally'' responsible for the Sept. 30 accident which
killed one and left over 400 others exposed to radiation.
Sumitomo Metal Mining owns JCO Co., the operator
of the fuel processing plant where three workers ignored regulations
while mixing nitric acid and highly enriched uranium, setting off an
uncontrolled atomic reaction.
Earlier this month, the government announced that it would repeal JCO's
operating license, but that Sumitomo would have a chance to appeal the
decision at a hearing in March.
Aoyagi said Tuesday [15 February] that the company planned to accept
the decision.
Nuclear power officials have still not succeeded in regaining the trust
of residents of Tokaimura, the town 70 miles northeast of Tokyo where
the accident took place.
Seventy-eight percent of respondents said they felt nuclear plants
were dangerous, against 62 percent who said they trusted nuclear facilities
before the accident, according to a poll conducted by the town government
cited Tuesday by Kyodo News.
The town polled 1,426 residents, and 546 replied.
JCO, which was set up in 1979 to process nuclear fuel, is owned 100
percent by Sumitomo Metal Mining, a leading Japanese comprehensive nonferrous
metal company.
Back
Nuclear guideline draft defines
what emergency is
Japan Times, 9 February 2000
A subcommittee of the Nuclear Safety Commission drew up guidelines
Wednesday that include a requirement for operators of nuclear facilities
to promptly inform local governments if monitors show gamma ray levels
of 5 microsieverts per hour.
Under the guidelines, the government would set up a task force headed
by the prime minister in the event radiation levels amount to 500 microsieverts
per hour. One microsievert is a thousandth of a millisievert.
The guidelines would be utilized in the government's efforts to galvanize
disaster prevention areas nationwide ahead of the implementation of
new laws regarding nuclear safety that were enacted by the Diet in December.
Under Wednesday's guidelines, operators would have to notify local
authorities if a monitoring device set up at the outermost point at
a facility registers radiation of at least 5 microsieverts per hour
for 10 minutes or more, or if two monitors pick up such radioactivity
at the same time.
While this level is not harmful to humans, the new guidelines require
prompt notification to authorities.
In addition, notification would also be required in the event unusual
readings are picked up by monitors placed near vents as well as when
problems that could lead to major disasters are detected.
If these new guidelines are applied to the September criticality accident
at the JCO Co. uranium-processing plant in Tokai, Ibaraki Prefecture,
notification would have been necessary immediately after the problem
occurred.
With the 800 microsieverts detected in the emergency monitoring that
ensued, a central government task force should have been set up swiftly
after the disaster, which was triggered by workers who used a bucket
to pour an unsafe amount of highly enriched uranium into a tank.
The latest revisions to nuclear safety legislation would have the
central government, rather than local municipalities, play a major role
in the event of nuclear disasters.
Back
Asahi Glass, Mitsubishi
Corp. to acquire BNFL subsidiary
Tokyo, February 7, 2000
Asahi Glass Co. and Mitsubishi Corp. said Monday they have agreed with
British Nuclear Fuels PLC (BNFL) to acquire all shares in BNFL's wholly
owned subsidiary F2 Chemicals Ltd. Asahi Glass and the trading house
will pay about 856 million yen ($8 million) to BNFL for the subsidiary,
as part of a plan to strengthen their fluorinated fine chemicals business,
officials of the two Japanese companies said.
Back
Nuclear leak worse than
first feared - More than 400 were
exposed to radiation in Japan.
The Guardian, February 2, 2000
By Jonathan Watts in Tokyo
Japan's worst nuclear accident exposed nearly five times as many people
to radiation as wasoriginally thought, the government said yesterday.
The sharp upward revision of the impact of the uncontrolled chain reaction
on September 30 is a fresh blow to public confidence in a nuclear industry
that has suffered a series of accidents and cover-ups over the past
few years.
Japan's science and technology agency revealed that 439 people were
exposed to neutron rays during the 20 hours in which the nuclear fission
took place at a uranium processing plant in Tokaimura, 80 miles northeast
of Tokyo.
In its initial report, the agency said only 69 people were affected.
The accident occurred when plant workers used buckets to mix nearly
eight times the correct amount of condensed uranium.
According to the agency's revised figures, the resulting fission exposed
119 residents, plant workers and emergency service staff to more than
one millisievert of radiation, which is the annual permissible level.
It is the first time that an accident in Japan has affected more than
100 people to such an extent.
One worker who battled to halt the chain reaction suffered as much
as 38 millisieverts and ambulance crews who arrived without being told
they were visiting a nuclear accident site were exposed to high levels
of radiation.
The agency played down the health implications of its findings, saying
that the risks of cancer only increased significantly with a dose of
more than 50 millisieverts. It said the revised figures were higher
because the later assessment included local residents.
"This makes the number look bigger than the original figures we reported,"
an agency official told reporters.
Anti-nuclear groups, however, said the data under played the seriousness
of the accident.
"We still don't think this is an accurate figure. It doesn't include
any people passing through the area at the time or those who were working
in nearby fields," said Kazue Suzuki of Greenpeace Japan.
The average incidence of leukaemia is 0.66% in Japan. According to
the International Commission of Radiological Protection, the risk increases
by 0.05 points for every 10 millisieverts of exposure.
The new figures are likely to add to public concern about the safety
of the nuclear industry. Since the chain reaction, several local governments
have halted or cancelled nuclear energy projects.
In the atmosphere of increased safety consciousness, British Nuclear
Fuels Ltd has lost contracts as a punishment for supplying reprocessed
fuel with falsified safety data.
Health officials have offered to monitor 120 people affected by radiation.
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