Quake devastation...and tracking what went wrong with Japan's nuclear reactors

At my house the TV is tuned to the Japanese channel for NHK’s coverage of the damage and devastation from Friday’s earthquake. It’s relentless coverage of the dead and missing, shots of people who have evacuated to shelters, bell chimes sounding new earthquake warnings, and the latest from the Fukushima power plant. 

Everyone is comparing the situation at Fukushima to past events: it’s worse than Three Mile Island but not as bad as Chernobyl. But will it become worse than Chernobyl? That’s unclear, but here are some sources to understand what is going on:

NPR has a visual guide to what went wrong inside the nuclear reactor. So far there have been explosions at 4 reactors. NPR is also tracking the latest news on the reactor.

A more detailed explanation of the fundamentals here.

Although people are concerned about the health effects of radiation exposure, this article from the Washington Post brings up the psychological damage that may have just as much significance.

And my summary from what I've gathered so far:

After the earthquake and tsunami the plant lost the necessary power to cool the fuel rods. The fuel rods contain fuel that generates heat through nuclear fission. The temperature of the fuel rods must remain stable to prevent a “nuclear meltdown” that could result in radiation leaks. With the cooling system failing, too much water boiled into steam and increased the pressure within the reactor. The power plant workers vented steam outside of the reactor to reduce the pressure, but they also added cooling water and caused hydrogen to build up inside the reactor. The steam and hydrogen gas were vented into the air and a hydrogen explosion occurred.

Also, I am following the updates on the situation at Fukushima because it's interesting and because there are health risks, but there is so much going on in Japan beyond what I can fathom. Ganbare Nippon!