Yes.

So, what's the worst-case scenario on the radiation/nuclear plants situation? My roommate is convinced its another Chernobyl.

I commented about his friends three years ago.

Is this the same guy you had the "out of pizza" debate with?

I kind of like JP's opinions, even though they seem to have gotten a bit muddled since his brain tumor.

http://www.jerrypournelle.com/view/2011/Q1/view666.html#Thursday

So what we've learned so far is that if external power supply is lost and diesels are rendered unusable, there can be quite some difficulties in maintaining control of nuclear plants, right? Is it really that unlikely that those conditions are met? (I can imagine: attack, heavy snow+low temperature, and, of course, tsunamis)
As far as I am informed, there are plants where backup-batteries are not available, and anyway, as we've seen, they don't last long enough to cool the whole thing.
That's not what I'd call safe.

Thanks. Nice..
I wonder though, could these pre- 8.9EQ small EQs be used as a warning sign. I'm sure they could hint, but.. This has to be somewhat reliable..

I wondered the same, but then again this might be the base level of earthquakes in that region. In this video you don't see what it looks like on any normal day.

Yes.
These were exceptional circumstances: an absolutely massive 9.0 magnitude earthquake (it got upgraded from 8.9, making it either the fourth or fifth strongest quake in the history of seismology) that first devastated the country, followed by a tsunami that simply razed everything hundreds of meters in from the shoreline in the affected areas.
Under normal circumstances, no matter what had happened at the plant, the plant operators could just request whatever they needed and get it there ASAP - personnel, external power, new generators, more fuel, more boric acid, special vehicles, or whatever.
But imagine trying to get help in the situation they were in, with bridges collapsed, power lines washed away, other power plants shut down, roads destroyed and blocked, thousands of people killed, injured and trapped, emergency services overwhelmed...

Latest reports say they've been using dihydrogen monoxide on the radioactive stuff! Some of it's reputed to be impure, as well!

Luckily, there's this thing called history, where stuff like "enormous, destructive earthquakes" or "tsunamis" tends to get recorded...
And while we can't reconstruct the actual seismometer data, we can estimate the magnitude from descriptions of the event and the damage done. And that tells us that, yes, this is indeed exceptional.

Also, a hundred years of data is pretty darned good for most types of risk assessments.

While the period of about 4000 years of written history is considerably longer than 100 years, it is still quite a short period of time compared to 4+ billions of years of earth's history, isn't it?

Still, there is no precise data for more than 100 years, and I doubt there is any data for anything before 1500. Cave-paintings don't count.

Now don't mislead by saying "a hundred years of data". The type of data is quite important. That's just nonsense in this context.
Considering the severe risks of nuclear plants' accidents with possible effects on generations to come, I wouldn't judge those among those "most risks".
Yawn.

That's beside the point.
Japan is also "known for big earthquakes".
The point is, whether it is pointless to judge an earthquake "exceptional" or not, building highly critical buildings on the basis of such a judgement.

But all this discussion is futile, I hope they will be able to avoid further spread of this stuff