A couple quick thoughts:
Aftershocks will be felt throughout the region, so unless you're planning to evacuate the
entire Japanese archipelago, it won't work. Also, Japanese architecture is as close to
earthquake-safe as you'll find anywhere.... as long as it isn't asked to soak up a 9.0......
At Chernobyl, the Russians had no one to blame but poor design and inadequate maintenance,
so they tried to downplay the severity of the problem. In Japan, they've just had an earthquake
of historical proportion, and while the power plants in question weren't immediately destroyed
or 'cracked open' by the spectacular forces applied to them, they did suffer damage that has
led to much more severe secondary issues. There's no shame in that, and there may be some
good to come from prompt action, so they're willing to work with anyone who can help.
The Japanese should feel a lot of shame here.
There have been earthquakes of this size and perhaps larger in recorded Japanese history.
Because seismographs weren't invented yet, an exact number can't be assigned.
But the descriptions of the damage puts them in the neighborhood of this quake,
perhaps a little less intense, perhaps a little more intense.
Ditto for tsunamis in Japan. There it's easier to say there have been larger ones.
How high the waves and mud flows went are recorded.
Nuclear is the most dangerous technology humans have made so far.
(Bio-tech is likely to succeed it.)
Nuclear plants should be designed to survive the worst disaster where they are located.
Not the most likely.
The plants in California are better designed and safer than those failing in Japan,
But they have not been designed for the worst earthquakes that occurs there.
Granted that shareholder profit, professionals that move between regulators and industry,
and the other problems that greed and ambition cause, I doubt we will ever design
nuclear power plants to be safe for the worst natural disasters.
Note that the organization with the best safety record with nuclear reactors does not have a perfect one.
The US Navy.
The money they spend is beyond what industry can afford to spend for nuclear reactors.
Oh, the nuclear industry in the US wasn't, until Congress passed a limit on liability per plant.
It's small compared to the risk. Yet another federal 'bailout' waiting to happen.