The nuclear reactiors had their buildings blown apart because steam built up inside, the hydrogen detached from the oxygen, and then exploded (as far as I can tell). It’s not as bad as it sounds. An explosion near a nuclear reaction and a nuclear explosion are two radically different things. Two reactors so far have gone up like this because the earthquake cut their power, and the tsunami flooded their generators – and I bet the shaking probably cracked or blocked up the pipes in and out of the reactor buildings too.
In any case, these explosions are not meltdowns in and of themselves. We are still not sure that there was or will be any meltdown. Judging from the reports of radiation levels so far there hasn’t been. (A meltdown happens when the actual radioactive material melts its container and leaks into the environment – as far as I know).
Of course I haven’t see ANYTHING with my own eyes, all I know is what comes in on the news. Here where we are in Southern Japan (Fukuoka) nothing at all is out of the ordinary. No shakes from quakes, not a drop from a wave, no blackouts, nothing at all. The damage in other parts of the county seems as far away from me as it probably does from you – well maybe a little closer, since it is the only thing on any TV channel for about 4 days straight now.
They are now expecting another tsunami about half the size of the previous. The amount of wreckage is mind-boggling. It is crazy how we live on huge slabs of rock that float on magma and lava. Compared to these huge forces of nature we live in houses of cards with toothpicks a tissues for property. In the natural areas where human beings haven’t built up card-towns and cities, the damage looks SO MUCH less severe, it almost looks serene.