[Updated 29 Apr; Intro updated 30 Apr; further update later on 30 Apr or 1 May.]
This NUREG looks like a hoax. It does not live up to its title, nor to its scope. One interesting point made, but not evaluated, is that peak cladding temperature (PCT) increases 14.4F for every 10F ambient temperature. The only thing which the NUREG evaluates is low level wind, and it doesn’t do a proper job of that.

Holtec Dry Casks of spent nuclear fuel sweltering on pavement in the Mississippi sun, on the river, with ultra-high humidity. The US NRC allows Holtec and others to pretend that the temperature is only 100F (38C).

“Impact of Variation in Environmental Conditions on the Thermal Performance of Dry Storage Casks”, NUREG, US NRC comment deadline MAY 4th-Nuclear Waste Dry Cask Storage Temperature, etc. http://www.regulations.gov/#!documentDetail;D=NRC-2014-0273-0001 ID: NRC-2014-0273-0001

Dry Casks at Diablo Canyon in California. NRC visit…