Your calculation is flawed, probably intentionally. A-380 is not a shell, it's a soft sausage 70 meters long. The fuselage collision would be stretched in tim

Your calculation is flawed, probably intentionally. A-380 is not a shell, it's a soft sausage 70 meters long. The fuselage collision would be stretched in time, greatly diminishing impact forces. It's large cross-section means it couldn't even focus on a single cask. The 40 F-4s analogy is incorrect again, as the tail of the plane wouldn't be hitting the target, it would be hitting the soft pile of crap from the nose and midsection. The engine is the only dangerous part as far as collisions against concrete go, and even then not so dangerous. Again, let's say we got unlucky and the 4 engines of an A-380 breached 4 casks. Would it be bad? Of course. Would it be as bad as 9/11? No way. The fireball would lift some dust in the air and quickly dilute it. Nuclear fuel is essentially ceramic and doesn't melt until 2800C, way above what jet fuel can do (steel beam anyone?). Some fission products would be included in the cloud. Local decontamination effort would be many orders of magnitude below that of Chernobyl (where health effects on cleanup workers proved impossible to measure) and probably on par with 9/11 cleanup.