Spent Fuel and Waste Science and Technology, Storage & Transportation R&D

b. Spent Fuel and Waste Science and Technology, Storage & Transportation R&D The possibility of stress corrosion cracking (SCC) in welded stainless steel dry storage canisters (DSC) for spent nuclear fuel (SNF) has been identified and studied as a potential safety concern. The welding procedure introduces high tensile residual stresses and changes in material properties in the heat-affected zone (HAZ) of the fabrication welds in the DSC. This welding procedure might promote pitting and SCC crack initiation and growth when exposed to an aggressive chemical environment. Some DSCs are stored in a marine environment, where an aggressive chemical environment might be produced by deliquescence of atmospheric salts, generating an aqueous brine layer on the surface of the canisters. Studies and research conducted so far indicate that the possibility of SCC in these canisters is low and that implementing technologies to mitigate SCC, by reducing the probability of cracks forming or growing, might further reduce the risks for long-term, extended storage of these DSCs. It is envisioned that the technology could be performed on the DSC while it is outside the storage overpack or the transportation cask, (possibly before loading with fuel, before placing in the storage overpack, or during transfer between storage overpack and transportation cask) or, if all the HAZ zones were accessible, while the DSC is inside the storage overpack. Research proposals are sought to develop mitigation technologies for enhancing the reliability of long-term storage and maintenance of DSCs (as constructed using existing designs). Possible technologies include sprays, coatings, weld depositions, and other techniques where long-term performance can be demonstrated empirically and/or analytically. Questions Contact: John Orchard, John.Orchard@doe.gov