In the opinion of one who has seen past the stainless steel and zirconium deep into the pile at PUR-1...and who has been watching close since 3/11...
1. I have no reason to believe in core, primary, or secondary containment integrity since day 2, F1, units 1-3. That doesn't mean all the scary stuff got loose, or that none did, it means that some did, and it ain't goin away anytime soon.
2.I have no reason to believe in SFP containment or rod integrity, units 1-6. Scary enough but 3 costs me sleep, MOX means P-239, scary as it gets, till you add in ancilliaries and byproducts, and they're in play too.
3. You get water hot enough, you can dissociate H2, but not enough to launch that much steel reinforced concrete that far. To do that, you have to heat Zirconium past 2300, in the presence of H2O. Figure it out.
4. HEU won't go supercrit, but P239 might, very long shot. Both will go crit in the right config and that'll spew just fine.
5. TEPCO lies.
6. Japanese politicians lie.
7. Mainstream Japanese media lie.
8. Best I got says the corium ate half a meter of the CV, out of 6-8 meters plus, BUT...there's cracks or other fails in the PV, CV, and secondary, cuz there's Sievert level hotspots out past the 30 km evac zone. Only one way that happens, core fuel outside.
9. I'm done w seafood.
10. West coast oughta be eating stable iodine, and watchin close.