There is an interesting and apparently well-informed discussion going on on the IAEA facebook page.

Specifically, there is some discussion about entombment (I blogged about this earlier, but the discussion doesn’t end there, it continues):

  1. Unfortunately, you can’t entomb live/melting reactors—-they would have to explode/burn off a large amount of material before they could bury the rest without a criticality. For example, clean up crews at Chernobyl stated at least 70% of it’s reactor had vaporized before entombment(contrary to official reports).
  2. Chris Ilderton ‎”The Science Guy’ on CNN is still spouting about cementing/entombing the reactors(while they are in the process of melting) Anyone got data on maximum tempature a fully molten core CAN reach?? I’m not thinking concrete is going to hold up.
    11 hours ago ·  
  3. Chris Ilderton I’ve heard 4 to 6,000 Farenheit for a fully molten core
  4. Chris Ilderton Apparently, If the Uranium melts, 2800c, the carbon and stainless steel or any amounts of concrete isn’t going to stop it from heading toward a large enough underground water source to cool it. Not good. Besides the Cladding breaking down/melting, what are the next signs to look for, especially if we don’t have access to temp reading?
  5. ‎@Chris (and everyone else), if a meltdown occurs, it will stop at some point, and that should be well before it escapes the bottom of the containment, here’s why. As it heats up and melts the Zircaloy cladding, it’ll pool up in the bottom …of the RPV. It will also melt some of the control rods, which adds hafnium and boron, both asborb neutrons and slow the reaction. If it’s still hot enough to melt through the bottom of the RPV, it will fall into the dry well. Each time it melts something, all that additional material gets mixed in with the fuel making it harder to sustain a reaction. At some point, it has absorbed enough steel, boron, zirconium, hafnium, and other materials that the reaction stops and it begins to cool (very slowly). more