That was before the cooling system exploded, crumbling the walls of the reactor containment facility and leaking even more radioactive material. These are the same containment facilities that we are constantly assured could take a direct hit from a 747 or withstand the strongest earthquakes. In fact the building did withstand the earthquake, it that turns out not to matter, because it set off a chain of events where the potential for much more serious problems, including a partial meltdown, are possible.
Of course, it is possible that things will be brought back under control. The plan is now to flood the reactor with seawater before temperatures can get high enough for the rods to melt. Perhaps a Japanese Chernobyl will be avoided. Perhaps it will remain only be a Japanese Three Mile Island. However, like the TMI incident, it is questionable whether this multi-billion dollar facility will ever operate again. Three other reactors in Japan also shut down, BTW, though presumably they shut down safely. Hopefully there will not be 4 Japanese Three Mile Island incidents. The quake was devastating enough without additional man-made disasters compounding the situation.
Imagine if a wind or solar generation facility that cost billions of dollars just suddenly and unpredictably became unusable. Imagine if a 20 kilometer radius around it had to be evacuated indefinitely. Imagine if three other billion dollar alternative energy plants also shut down indefinitely.
Nuclear power boosters, after licking their wounds for a while and declaring everyone else to have over-reacted, often sit around nursing their broken hearts. Nuclear power lets them down again and again, but like battered housewives, they dutifully return to it, and in relatively short order. They always talk about the good that they see in it. They talk about the latest, greatest, fancy, high-tech reactors that cannot possibly let them down the way the current ones seem to. They talk about all the times that things didn't go wrong, and how this is just a minor blip.
Of course, if we were getting 100% of our power from this type of nuclear facility then it would be a blip multiplied at least 10 fold. Instead of only having a near disaster every couple decades, we might have only every couple years. And the odds of a near disaster turning into a total disaster also increase.
I believe that the newest, safest forms of nuclear fission should continue to be investigated, but it should only be part of the power mix, not anywhere near 100%. The main reason is cost, and the next major reason is that fact that these facilities are never as safe in practice as they are claimed to be in theory. The latest generation reactors, such as Pebble Bed Moderated Reactors (PBMB) or even Liquid Fluoride Thorium Moderated Reactors (LFTMR) supposedly cannot melt down the same way. PBMRs, are not even cooled with water, and supposedly the encased "pebble" fuel would stop producing heat efficiently without the circulation of a coolant. LFTMRs also avoid the buildup of Xenon, and have no fuel rods at all. Yet these are never the reactors that seem to get built, perhaps because they would be way more expensive than the older, mass-producible generations of reactors we have today.
It is, simple put, 100% false that there are no credible alternatives to nuclear. The same amount of money and time spent drilling super-deep geothermal wells would likewise produce huge amounts of power that was always available, for example. However, the main issue is avoiding one-size-fits-all thinking. Having multiple, diversified power sources makes things more robust, not less. The wind doesn't blow all the time, but it's always blowing somewhere and the sun is pretty predictable too, especially in the desert.
Demand for power itself is variable, so it is acceptable to have variable sources of generation. The problem with nuclear is that it does not vary easily with demand and therefore a lot of power generated at low peak times must be stored. Without certain renewables, like hydro power, nuclear would be even more wasteful than it is already, because there would be no practical way to store this excess production.
The point is that we not put all our eggs in one nuclear basket. All but the most blinded by love should be able to see that now, one would hope.