I've asked the Union of Concerned Scientists why they think the staff at the neighboring Fukushima 2 plant were evidently successful in achieving "cold shut-down" of their four operating reactors after the earthquake and tsunami, while experiencing a similar loss of energy supply to the back-up cooling pumps. See Wikipedia Fukushima Nuclear Plant 2 for reference.

Fukushima 1 appears to have similar reactor models (Mark 1) but 6 units compared with 4 units at Fukushima 2. They are in close geographic proximity. Were the effects of the earthquake and tsunami markedly different? Or was it what the operating staff did, or didn't do, with what resources they had available? This question belongs in "lessons to be learned."

I need to correct one of my statements posted above relating to the Three Mile Island accident in 1979. It took over 5 years, not 1 year as I remembered, before scientists were able to examine the bottom of the reactor vessel and confirm that there was a partial meltdown of the fuel rods (over 50%) in the containment vessel, and that the "melt" had eaten through the vessel walls. The containment dome fortunately functioned as designed. By that time media attention had shifted to other issues and the public by and large is unaware that there was a meltdown at Three Mile Island.

Charley Noble