The IAEA Web Site
The criteria for the various levels – Fukushima #1 is now at 6+
INES 1-7 Scale
The manual explaining the scale is available here
The scale is logarithmic – each level is 10 times worse than the prior level.
Live Coverage from Japan’s English Language TV service:
It’s stunning how good NHK is in a very difficult situation. NHK is no Fox News. They’re very careful to keep to the facts. Their English translators are exceptionally good – they didn’t trip up at all when the person speaking was explaining that someone had caused confusiong by confusing milliSieverts with MicroSieverts. A translator who can translate technical jargon is very impressive.
Yesterday, while they were describing what was going on, the Tokyo area was hit by 6.0 earth quake, and they didn’t miss a beat. With a minute or so, they knew the magnitude and location and had the alerts up, and knew in another minute that there would not be a tsunami.
Thanks for posting the scale. What’s interesting about the Three Mile Island accident is that it qualifies for a 5 rating on core damage, but only a 2 on public and nuclear worker radiation exposure.
What we may be seeing is that the U.S. takes the phrase “defense in depth” a lot more seriously than other countries. When (not if) China has their first publicized accident we’ll get another data point on that. They’ve already blown up a bunch of coal plants with their poorly made steel. It’s just a matter of time before they do the same with a nuke plant.
Looking at the scale, it struck me that TMI wasn’t a 5.
I think they even stipulate the scale is a political tool to inform the public (or not), and there isn’t really any science behind it
The really obvious flaw right now is it is a scale assuming only one event at a time. Do four 6’s equal a 7?