Damage of Ventilation System in the Fire and Explosion Incident at Bituminization Demonstration Facility of PNC Tokai Works

摘要

The Bituminization Demonstration Facility of Tokai Reprocessing Plant had a fire and explosion incident. Failure of the ventilation system (plugging of HEPA filters) occurred soon after ignition and the system was subsequently shut down. This ventilation failure led to the release of radioactive materials from the hot cells, because negative pressure in the cells was lost. In addition, this failure resulted in the accumulation of flammable gasses in the filling room, which caused the subsequent explosion. The explosion damaged a lot of equipment including the ventilation system, such as filters and ducts. Damage to the filters in the cell ventilation system was significant. The filter media were sooty and some of them were displaced by blast. The blast initiated many noticeable dents in the ventilation ducts. This paper presents the operating condition of ventilation system during the incident and the damages to the filters and ducts.