Tokai JCO Criticality Accident
Report 12/16/99 18:20
Uranium Solution in the Hose Collected: Missing Solution Found?
Uranium solution that was left in a hose used during the accident was collected on December 13th. The hose was used to pour in aqueous boric acid into the precipitation tank on October 1st after the cooling water was extracted to contain the state of criticality. Aqueous boric acid was poured in to make sure that the state of the precipitation tank was and would remain subcritical.
24.1 liters of uranium solution was left in the hose; a figure which is very close to the amount of uranium solution that was missing when the first sample was collected from the precipitation tank on October 20th. (See the report 13: 20 Liters of Uranium Solution in the Precipitation Basin Missing)
The solution will be put into a stainless steel bottle to be used for transportation and will eventually be sent to the Japan Nuclear Cycle Development Institute (JNC). The solution, however, will be stored on JCO site for a while. The hose will be treated as radioactive waste and will be put into a storage room within the JCO site with other radio-waste produced from this accident.
29 JCO employees, 2 officials of Science and Technology Agency, and one Ibaraki prefectural official carried out this task. Exposure level of these people varied from 0-176micro Sv.