Reply #3: Given the situation and from what I've read, there already have been rolling criticalities...

[Poll_Blind]

...and there is no guarantee that they have stopped or slowed.

High neutron bursts are indicators of criticality and there have been a number of them reported since the disaster. Normally, I have read that an uncontrolled criticality will explode (NOT nuclear bomb style) to pieces, thus making a criticality (which requires the fuel be reasonably concentrated) usually a temporary affair. However, this is mostly guesswork. There is every reason to believe that water being pumped in could be causing the fuel to move and temporarily form pools which allow it to reach criticality. This could go on indefinitely, until the fuel (in whatever state it is in) is unable to coalesce in such a fashion.

PB