For those who missed my previous diaries on this topic, I have a background in physics and worked at Oyster Creek Nuclear Generating Station providing computer support for the reactor core engineering group. For the entire qualifications spiel and/or some background on Boiling Water Reactor (BWR) containment structures, see
Everything You Never Wanted to Know about Nuclear Containments
That diary also contained a review of the then current status of each of the reactors at Fukushima. In this diary I will be updating that status information and discussing the various possibilities moving forward from here and their relative likelihood. This update is based on information from a number of sources including the UN's International Atomic Energy Agency, IAEA, and media reports which quote directly from organizations such as Japan's Nuclear and Industrial Safety Agency. My intention here is to tie together the various strands of information to provide an overall picture of things and explain it in a way that is accessible to those without scientific training.
This diary and others like it are not intended as a substitute for the ongoing liveblog diaries, but rather, to pull all of the info together in summary form.
I have also written previously on the topic of meltdowns in the diary