Tokai JCO Criticality Accident
Report 10/16/99 11:20
The second "Accident Investigation Committee"
The second "Accident Investigation Committee" of the Nuclear Safety Commission was held on Oct. 15, 1999. It was announced at the first meeting that this committee will be held every Friday in order to put out a full investigative report on the accident by the end of this year. There were only 15 spots open for public hearing. About 60 people came, and 15 people were admitted in by lottery. Usually written information to be used at the committee is handed to the people who did not win the lottery. However, the officials were very reluctant to give out information. In fact, our staff members had to force them to hand us information. (Unfortunately, our staff members did not win the lottery). Graphics, maps, and data, including revised data on radiation exposure, were released. The official number of exposed people have risen to 69 from 49 people. Also, it was revealed that one of the workers, who carried out the water extraction operation to contain the criticality, had been exposed to 112 mSv of neutron radiation. This number is higher than the regulated amount of 100 mSv for plant workers when carrying out an operation during emergency. (A limit of 100 mSv per operation, which in this case was the water extraction that was a couple minutes long on each attempt.) Normally, the limit on plant workers radiation exposure is 50 mSv per year.