What's the deal with the nuclear power plants in Japan (and elsewhere)?

The devastation caused by the earthquake and subsequent tsunami in Japan is horrendous and my thoughts and prayers are with the people of Japan!

Reading the news about the new threat of a nuclear meltdown on top of all the mess they are facing is frightening. It’s been too long since my last Physics class, so I did some research to see what problems they’re dealing with.

My first gut reaction was “Why don’t they just shut it down?” Well, apparently this is not possible. You can turn off the reactor, but the nuclear raw material is still there, still producing energy as it breaks down and is heating up in the process. Hence the need to continually douse water onto it to prevent above mentioned meltdown. Problem is, they cannot get enough water quickly enough to facilitate the process. The only way to stop the fission safely is to introduce a compound that absorbs the excess neutrons. The chemical element boron seems to be the compound of choice. Soooo, this begs the question why “they” don’t have large quantities of this stuff handy. Wouldn’t you want to cover your bases???

The next question is “What about here?” Are we prepared for a disaster of this proportion??? Answer: Ahh, no! Nuclear energy has for years been billed as a clean alternative to oil and coal, were the benefits supposedly outweigh the risks. Fine! As long as you properly prepare for said risks, and clearly we’re not! Hasn’t the world learned from Three Mile Island and Chernobyl???