To add that there is not enough drinking water, food and and fuel. It's hell on earth.
A very good cnn.com article with an excellent diagram of the reactor system. Unfortunately they misnomer it as a "boiling water" reactor, which it is not. The boiling occurs in the boiler, on the secondary loop side (see diagram). Boiling in the reactor itself would be bad, bad.
There are some errors in the article, but these Fukushima units are BWR's.
Eating iodine pills for no real reason can't be a good thing and timing is everything? I would wait for official instructions.