Study on the cause of the fire and explosion incident at Bituminization Demonstration Facility of PNC Tokai Works

On March 11, 1997, a fire and explosion incident occurred in Bituminization Demonstration Facility (BDF) at Tokai Reprocessing Plant (TRP). The cause of the incident was thoroughly investigated and after thirty meetings of 'Investigation Committee of Science and Technology Agency (STA)'. STA reported possible cause of this incident. Continually detailed investigation was discussed at 'Follow-up Committee of STA'. Based on the results of five meetings, JNC concluded that the main cause of fire was frictional heating and viscous heating in the extruder, which provided an unusually high temperature in the bituminized product at filling, since there was no chemical analysis data suggesting the generation of chemical heat. It is considered that these excessive heat generations were due to the decreased feed rate of liquid waste to the extruder. The Follow-up Committee almost agreed to this conclusion. This paper describes general information concerning the incident and details of the cause of the incident. (author)