javadave said:
I am just a finance guy, but I've been reading up on the current crisis and found this blog. Anyone here thing this guy might actually be correct in his assumptions?
http://atomicinsights.blogspot.com/2011/03/focus-on-food-water-shelter-dr-greg.html
The fuel rods however are not at pool temperature. They are a bit hotter. I think at 183°F, there is a fair amount of evaporation - from the top of the pool. If the rods are 30°F hotter, then steam can form on the surface. Those bubble rise up through the water and out into the air.
The author is not quite correct on the oxidation of UO
2. UO
2 is one form. U
4O
9 (O/U = 2.25) and U
3O
8 (O/U = 2.67) are higher order oxides. There is also UO
3, which is water soluble, so one might be looking at hydroxides, but I don't think that should happen necessarily for UO
2 in the SFP, and the other higher oxides are less likely at SFP conditions.
The issue is not the UO
2 ceramic fuel per se, but the Zircaloy-2 (Zr-2) cladding surrounding the ceramic fuel. It is the cladding which retains the fission product, and is the first barrier between fission products and the environment.
The concern is that the Zr-2 cladding gets too hot and in contact with steam, or more so air (21% O), then the Zr-2 would oxidize/corrode to failure. Then the fuel rod would release fission products such as Xe, Kr, I, Cs, . . . .