FUKUSHIMA DAIICHI UNIT 3 EXPLOSION AND A METAL WATER REACTION ACCIDENT

摘要

Titanium, Zirconium, and Hafnium reacts with water, displacing hydrogen at elevated temperature. Zirconium components in the core of Fukushima Daiichi Unit 3 reacted with water and generated hydrogen that ignited in the buildings of Unit 3 and 4. Titanium components in the electrolysis cell of Kyusyu University reacted with water and generated hydrogen that also ignited in the hydrogen station. Both explosions are recorded as motion pictures. A brief presentation on the explosion in the electrolysis cell of Kyusyu University took place in the fourth meeting on fire safety of the Nuclear Safety Commission of Japan on December 14, 2007 to inform the nuclear safety community on the metal water reaction in a pressure vessel. The released dense fluid cloud absorbed the external light and the brightness in the unit space decreased rapidly. The video frame brightness was plotted with time to examine the fluid release behavior. The estimated opening area is 253 square millimeters. The estimated cell volume is 0.022 cubic meters. The major fluid ejection continues 20 seconds. The estimated fluid velocity is 4.5 m/s. The video flame brightness of the Unit 3 reactor was plotted with time to compare the case in Kyusyu University. The obtained curve is similar with that in the case of Kyusyu University. Both curves show explosion, dark fluid release, decreasing of release rate, and transition to steam flow. The fluid ejection period of Fukushima Daiichi Unit 3 is 160 s.