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Tokai JCO Criticality Accident

CNIC's Statement on the Criticality Accident at  Tokai

There has been a criticality accident at JCO Ltd. Tokai site. Three workers were hospitalized for acute radiation injury. A large amount of radioactivity released into the atmosphere and a radiation amount 16000 times normal amount was measured. Thirty-nine households (150 people) were evacuated and 200m radius of the site was declared off-limits. The roads in the 3km radius of the site were closed and residents within 10 km radius of the site were advised to stay indoors. A criticality accident of this nature at a Japanese nuclear facility has never occurred before, and the situation is serious. The nuclear industry, the Science and Technology Agency (STA), and the overseeing governmental offices that allowed this serious accident face grave responsibility.

CNIC demands an absolutely thorough investigation, and demands that the plant be shut down. We also demand a full inspection of the safety measures system and a review of the existing safety inspection system. Furthermore, any other facilities without adequate safety measures to respond to a criticality accident should be shut down immediately.

It has been reported that the criticality explosion accident happened during a refining process for highly-enriched uranium for the fast breeder test reactor, Joyo. Sixteen kg of highly-enriched uranium was filled into a settling basin designed for no more than 2.4 kg, an amount almost 6.5 times more than it should have been.

For such act to take place, there must have been a serious flaw in the criticality control or the criticality control system of the plant itself had been insufficient. Furthermore, twelve hours after the accident at the time of this press release, the criticality explosion has not yet ceased, and the radioactive count is still high in the vicinity of the site. Sufficient action has not been taken in response to the accident or to isolate the site. We find the following points problematic: the structure and the sealed nature of the site; the fact that a plant dealing with highly-enriched uranium was built adjacent to a residential area of ordinary citizens; and that the safety regulations were far looser for this plant compared to nuclear power plants.

This accident has proved that the existing criteria for the location of the site and safety regulation systems that disregard the dangers of nuclear material are significantly flawed. In addition, the delay in notifying local government and the residents, and the lack of sufficient information concerning this accident has brought to light the inability of the nuclear industry and the STA to sufficiently respond to an emergency. Even at an area like Tokai village where there are a number of nuclear facilities including nuclear power plant, it took one hour for the accident to be reported, and not even the evacuees were given accurate information on the matter. In view of these facts, we assert that the company and the STA that cannot even grasp an accurate situation of the accident are not capable of handling nuclear materials. By denying the possibility of the criticality accident, and neglecting to secure the safety of local residents , the nuclear industry and the STA have indirectly allowed this criticality combustion accident to happen. This fact should not be taken lightly and the responsibility of company and the STA is grave.

This accident has brought to light the dissembling nature of the Japanese government’s nuclear policy that has been concealing the danger of nuclear utilization with the myth of the safety of nuclear energy. CNIC strongly calls on the state, STA, Ministry of Trade and Industry, to openly lay out the dangers and problems of nuclear energy utilization and to scrutinize the propriety of current nuclear energy policies.

An English translation of the statement issued at 1:30 a.m. 10/1/99


Citizens' Nuclear Information Center
Akebonobashi Co-op 2F-B, 8-5 Sumiyoshi-cho,
Shinjuku-ku, Tokyo, 162-0065, Japan