For all the scorn that creationists (justifiably) receive, scientific ignorance in the form of nuclear scaremongering has done and is doing far more damage.
Considering the population density and the inherent risks (quakes) in Japan, I would say it's a wise decision. Who wants a population living under fear?
Fission is a good source of energy, but nuclear plants are obviously less reliable than expected. That will be a thrust to research better alternatives, including better nuclear plant designs, why not?
Had it been a gas plant or whatever, it wouldn't have mattered. But it was a nuclear plant, and in a nuclear plant any improbable event like that is a major f* up. That's the core issue.
... it would have been doing damage constantly, just by operating, in the form of emitting carbon.
I'd like to think the right managers and authorities will do the right thing in such situations. But empirically, they didn't.
Perhaps it's a specific failing of the Japanese governance regime, and knowing their own affairs more than we do, they don't have sufficient confidence they can fix that failing before another 'freak' event occurs.
Are you seriously suggesting that anything that isn't designed against every conceivable example of human incompetence, is a flawed design?
Even though management was criminally bad, Fukushima still killed fewer people than the equivalent number of coal plants run for the same time. Fukushima ran for 40 years, so that's 25 deaths per year worst-case. According to the CATF[1], around 13,000 Americans die each year from fossil fuel power plant emissions. There are around 600 coal plants in the US, so that's just over 20 deaths per plant per year. What's worse is you need more than one coal plant to make up for a nuclear plant. Googling around tells me coal averages 300MW/plant and Fukushima had 4.7GW of capacity. You'd need 15 coal plants to make up for Fukushima. That's 300 deaths per year.
So when the 5th largest earthquake ever recorded strikes, and causes a nuclear power plant to explode twice, and the cleanup is criminally mismanaged, it's still safer than burning fossil fuels.
1. http://www.catf.us/fossil/problems/power_plants/existing/
As for the severity of the earthquake, it's far more important to consider proximity than absolute magnitude. A smaller one closer or right under could have been catastrophic. A few of us consider building plants in active tectonic zones to be the height of insanity. Building it right by the shore, in historical tsunami zones? Incomprehensibly stupid.
Of course, the alternative to nuclear isn't just coal. Renewables and efficiency should be considered first. Safer than both coal and nuclear, they also create more jobs.
For the same amount of energy, renewables kill more people than nuclear. People fall off their roofs installing solar panels. Hydroelectric dams burst. Even windmills kill people.
For the next few decades, fossil fuels are the only alternative to nuclear power. Wind and solar aren't baseload sources. Hydro is, but we've already put dams in most of the economically and environmentally feasible locations.
There are lots of environmental impacts of renewable energy, but generally the acceptance is higher than for nuclear or coal.
Here's a tangentially-related fact: France is the world's largest energy exporter. 75% of their production comes from nuclear. Germany is still dependent on nuclear power, they just passed the buck.
Yet for both wind and solar, this reflects all known risk, while for nuclear we still have to deal with catastrophic risks as well as storage of spent fuel.
As to the only alternative to nuclear being fossil fuels, someone should tell it to countries investing in solar power (especially concentrated) or wind. Germany and China come to mind.
The Fukushima reactors were the most dangerous design currently still in operation in G-7 countries, and handling of the aftermath of the earthquake and tsunami was one of the most disorganized and most mismanaged in history. And yet for all of that the nuclear disaster still resulted in far fewer deaths than occurred in coal mining in that year.
http://www.youtube.com/watch?v=cZYT6BjfBro (1m15s in)
(death toll from that fire, explosions around it and people locking themselves in their homes, then getting enveloped by the smoke, was over 200. It was not the only oil disaster during the earthquake)
Let me tell you about how many people die each year from the hydroelectrics that power 90% of my country.
Reactors cannot withstand such earthquakes. After the earthquake most of Japan's reactors are shutdown. After such an earthquake you need to inspect them, for example to find problems in pipes, pumps, and various other installations.
What Fukushima showed was that a loss of power over a long period of time made problems. The power lines bringing outside electricity were destroyed. Roads were damaged. Other generators were not available.
It's not clear that a similar situation could not happen caused by an extremely strong earthquake much nearer to a power plant.