Current measurements indicate that in the last hour, radiation was released between the Fukushima Dai-ichi #2 and #3 reactors equivalent to 8 times what a person would normally experience over the course of a year. So, not an unmitigated disaster yet, but things are looking very bad.
It is significant to note that they have now confirmed leakage from the #3 (MOX-fueled) reactor in addition to the #2 reactor. Additionally, they have found a crack in the outer containment chamber of the #4 reactor, which was shut down for routine maintenance and is not “hot”.
Currently, the #2 reactor has 2.4 metres of its fuel rods exposed. Partial nuclear meltdown is assured and the game is all about preventing a complete meltdown. It’s important to note that a Chernobyl-like explosion is practically impossible, but a complete meltdown could completely breach the suppression pool and all containment walls, leaving the immediate environment completely exposed to the hot fuel.
In the 20-km radius around the reactor, people who have refused evacuation have been strongly warned to remain indoors. I wish I could say that would make a huge difference, but air and particulate does move within homes even when windows are shut. It might help, but it won’t solve the problem.
It has also been confirmed that there is a southerly wind flow from Fukushima to Tokyo. This will without doubt bring radioactive isotopes into the area.
Eat yer konbu, kids. And, I reiterate, all those who are in the potential fallout path should not delay in taking prophylactic potassium iodide. It won’t help protect from cesium isotopes, but it will help protect from radioactive iodine isotopes. Be smart and make healthful decisions.
Updated to change the exposure amount from three times higher to 8 times higher than normal in a year.