The earthquake in Japan was awful. However, it really wasn't that unusual. There will be earthquakes of comparable magnitude on an occasional basis. Rational policy making must take this reality into account.
Let's look at the biggest potential threat from the earthquake in Japan. Yesterday, the (Union of Concerned Scientists 3/11/11) issued a press release on the dangers posed by the first of two nuclear power plants in Japan.
If battery power is depleted before AC power is restored, however, the RCIC will stop supplying water to the core and the water level in the reactor core could drop. If it drops far enough, the core would overheat and the fuel would become damaged. Ultimately, a “meltdown” could occur: the core could become so hot that it forms a molten mass that melts through the steel reactor vessel. This would release a large amount of radioactivity from the vessel into the containment building that surrounds the vessel.
The containment building’s main purpose is to keep radioactivity from being released into the environment. A meltdown would build up pressure in the containment building. At this point we do not know if the earthquake damaged the containment building enough to undermine its ability to contain the pressure and allow radioactivity to leak out.
It gets worse. The Sydney Morning Herald is reporting similar concerns with a second nuclear power plant damaged by the earthquake.
If you want to understand what a nuclear meltdown is, think Chernobyl.
I certainly hope Japan and everyone downwind are lucky enough to avoid a meltdown and its consequences, but if we keep allowing nuclear power plants to operate near earthquake faults (or areas that experience hurricanes/typhoons), the kind of meltdowns people are worried about are inevitable at some point in the future.
It also is important to remember that terrorists could cause nuclear meltdowns at any nuclear power plants with significantly less effort than was expended with the 911 attacks. (Claims to the contrary from the nuclear industry and its bought politicians and pundits are as nonsensical as claims by the tobacco companies in the early 20th Century that cigarette smoking was good for peoples' health.)
Every nuclear power plant is a potential weapon of mass destruction.
How many more terrible nuclear disasters will it take before we get a clue and switch from nuclear power to green energy like wind, solar, tidal, and geothermal power? When will we start getting serious about conservation by dramatically reducing international trade and by expanding public transportation?