One thing is clear. If meltdown results in fuel in the bottom of the reactor vessel it would not be dispersed but concentrated and the suppression pool would not be the destination. Instead, it would either remain in the bottom of the reactor vessel or melt its way through and fall out the bottom. Unless the diagram is incomplete all of the assurances that re-criticality is impossible are just PR. They HAVE to keep the core below the point at which zirconium begins to decompose to prevent disaster. And some pumps for this process are INSIDE the reactor vessel. The jet pumps better not fail.

If the core goes dry only the boron might help. I wonder how much boron is in the boron storage tanks and what form it takes. My guess is boric acid. Anyone have any idea what would happen if 10Kg of fuel pellets fell to the bottom of the reactor vessel and were covered with boric acid? How about 20Kg with some pellets on top of others?

"It is not necessary to have hope in order to persevere."