Follow-up to: NRC officials suspected a ‘detonation’ at Reactor No. 1 weeks before Gundersen postulated that scenario at No. 3
First there was a suspected detonation at Unit 3, then at Unit 1, and now at Unit 4. The distinction between a detonation and deflagration is discussed here: Japanese study says ‘detonation’ occurred at Unit 3 — “No containment in the world can withstand a detonation shockwave” (VIDEO)
Via Team H2O Project, director Kenichi Ohmae (http://www.fairewinds.com/sites/fairewinds.org/files/Fuku%20Timeline.pdf):
Chronology of Unit 4 […]
04:08 SFP temperature was confirmed as 84*C.
11:01 Unit 3 explosion
06:12 (Highlighted Yellow) Huge detonation sound. Reactor building severely damaged (4th & 5th floor)
If we calculate the amount of hydrogen, which were generated and detonated in No.3, and shifted to No. 4, could the explosion in No. 4 explosion occur?
• TEPCO calculated that the amount of hydrogen generated in No. 3 from the time of meltdown to explosion was about 600-700 kg.
• This amount needs to be sufficient to destroy the floor 4 & 5 of No. 3. and floor 4 & 5 of No. 4. => 12% of hydrogen level destroys 400 mm concrete on 4th floor. 4% of hydrogen level destroys 250 nun concrete on 5th floor.
• Theoretically. 600-700 kg of hydrogen could accumulate in the level above (more than 12% on 4th Fl.. and 4% on 5th Fl.). However, approximately more than 13% of hydrogen level is necessary for detonation [Emphasis Added]. Further verification is necessary.
Nuclear expert Arnie Gundersen explains more about the differences between a detonation and a deflagration here