[justa-hairyape]

At that temperature just about everything inside the RPV melted. Brackets, control rods, etc... When it mixes all together becomes something called corium. Here is what we have right slowing flowing out the holes of reactor #1.

Above image from Wikipedia and shows the corium flow out from the Chernobyl reactor. That corium at Fukushima is probably flowing to the same area where the water is pooling.

[Chode]

just damn...