I wrote on December 31, 2011 about the blowout panels in the reactor buildings at Fukushima I Nuclear Power Plant may have been welded shut except for the Reactor 2 building when the earthquake and tsunami hit on March 11, 2011 and the nuclear accident started, and that may have caused explosions in Reactors 1, 3, 4.
It doesn't seem anyone attending TEPCO's conference have asked questions on that since. Now that the accident is supposedly "over", what really happened, why, and how back in March 2011 may be of no one's interest. But I remain extremely curious and I want to understand.
So I decided to look for the photographs that show Fuku-I Plant from the oceanside. From the photos below, what I can say is not much. The blowout panel of Reactor 2 building popped sometime between March 12 before the Reactor 1 explosion and March 13. The blowout panels of Reactor 3 and Reactor 4 didn't open at all for whatever reason, and the buildings blew up.
It would be nice to find a photo on March 14 before Reactor 3 blew up, and on March 15 before Reactor 4 blew up at 6:00AM. So far, I haven't managed to find these.
March 11, 2011, after the earthquake and tsunami: Screenshot of the infrared video taken at 10:25PM by the Self Defense Force, aired on NNN News that day seems to indicate the location of the blowout panels in each reactor building. Reactor 1 doesn't even seem to have a blowout panel.
March 12, 2011, before the explosion of Reactor 1: The blowout panels in all 4 reactor buildings seem to be intact. (Photo from Gigapica.)
March 13, 2011: Reactor 1 in ruins after the explosion on March 12. The blowout panel of Reactor 2 looks to be open. (Photo is from DigitalGlobe.)
March 16, 2011: After the explosions of Reactor 3 and 4. (Photo from DigitalGlobe)