As the above poster has pointed out, almost everything we’ve ever been told about Fukushima by the Japanese government, TEPCO, and other nuclear-industry apologists has turned out to have been wildly optimistic.

“Confidently dismiss” and “Fukishma” do not go together very well these days. Especially with TEPCO lying it’s ass off.

Though I do agree that that particular scenario is somewhat extreme. The fact remains that the idea that much of the core material is in containment is at this point absurd. For at least two reactors it has mostly gotten out. TEPCO seems to have no idea what is going on geologically below the plant.

I would not want to rule anything out at this point.

Uh – how is that supposed to happen? Really, to melt through the concrete alone the pellets would have to get so hot that they’d vaporize. If the concrete is cracked then fine particles or dissolved material could wash into the soil below, but in that case the material will be diluted so much that it would quench quickly and not continually produce huge amounts of heat through residual fission. Alternatively we can imagine the pellets have fallen into large cracks in the concrete and agglomerated enough to continue to fission (which is a possibility given the huge amount of fuel in the core). However, we can confidently dismiss the “continuing to melt its way through the earth” bit.