Many nuclear plants have begun or will have to start storing spent nuclear waste in onsite dry storage
containers, because the room in the spent fuel pools is reaching capacity. Some of these plants are
located close to the coast and are in chloride-rich environments. Because the dry storage containers
may be made of austenitic stainless steel, a potential concern is their susceptibility to chloride induced
stress corrosion cracking. The objective of this work is to evaluate the stress corrosion cracking
susceptibility of austenitic type 304, 304L, and 316L stainless steel to chloride stress corrosion
cracking. U-bend samples were created out of these alloys and assembled in an environmental
chamber. The U-bend samples were heated to various temperatures and subjected to an accelerated
corrosion tests, involving directly spraying the samples with simulated sea salt. Cracking was observed
in all the samples except those where the temperature remained below a chloride stress corrosion
cracking temperature limit. The test was overly conservative because of the direct spray, which is not
expected to occur at the actual storage facilities. Secondly, the spray altered U-bend samples
temperature making it more susceptible to SCC. In order to create a more realistic, but conservative
accelerated test, the factors important to chloride stress corrosion cracking (i.e., relative humidity and
temperature) were examined.
Keywords: Stainless Steel, Stress Corrosion Cracking, Atmospheric Corrosion