Reply #24: Yep. People seem to be making a VERY big deal about a pretty small chage.

[FBaggins]

We knew there was a meltdown in all three active reactors... and they reported as much from very early on. We didn't know how far "melted down" things were, but they really still don't "know". We didn't know (and still don't) whether the fuel was partially suspended near it's original location (unlikely now), or at the bottom of the RPV (likely) or at the bottom of the containment (or some combination) - and we still don't "know".

The prior estimate was based on what was found in the water that leaked out... a very inexact science since the chemistry involved is not well understood and the exact conditions were not known (the same reason that Iodine released at TMI were much lower than expected and the iodine component was higher than expected at one point here - causing some to incorrectly assume recriticality). The current estimate is based on recently worked-on sensors that might or might not be accurate.

Yet suddenly all the whacky theories that were out in left field from day one are carted back onto the stage in a hope that NOW they don't look so off-base. Active fission... still-molten cores... burned through all containment and on their way to the water table...prompt-critical explosions... and on and on.