The Spent Nuclear Fuel(SNF) are moved to canisters for long term dry storage. These canisters are large welded stainless steel structures without post-weld heat treatment, possibly leaving large welding residual stresses. Furthermore these canisters are likely to be placed in costal regions and thus may be susceptible to chloride-induced stress corrosion cracking. For linear fracture mechanic-based structural integrity assessment, the stress intensity factors are needed for crack growth analysis. However ASME B&PV code and R6 code don’t include Ri/T of canisters. In this study, stress intensity factor of SNF canisters with axial through-wall crack is calculated using FE analysis and compared with API code.