[Errant]

the radiative heat loss is such that you don't approach the melting point of uranium oxide, much less vaporization.

Sounds reasonable. I would think you also get (maybe) enough contamination from the rods themselves during any melting, to throttle reaction among the pellets. Otherwise, why go to the trouble to build the the rods that way.

I'll keep my fingers crossed and regularly pray just to stay on the safe-side. ;)

I'd appreciate a ping or freepmail if you come to a different conclusion later, or if something unforeseen arises.

Thanks,

[chimera]

Certainly if heat energy is absorbed by the cladding to the point of cracking or melting, that will carry off a significant amount of thermal energy. Whenever you have a phase change you get a “bonus” in heat removal. That's why wet cooling towers are very nice for cooling of the condenser recirc water in a power plant.

But in the event of fuel overheating, it is better if the cladding takes the heat than just the fuel pellets alone.