Welded austenitic stainless steels are considered as the materials for dry storage canisters containing spent nuclear fuel. Since the canister is a primary barrier to prevent the release of fission product, its structural integrity during the entire storage period is the safety concern. However, austenitic stainless steels are susceptible to chloride induced stress corrosion cracking (CISCC), particularly in the presence of residual tensile stress and sensitization from welding procedure. In Taiwan, dry storage systems are located at a coastal site, thus CISCC may occur on canisters surface due to the deliquescence of salts. Therefore, the purpose of this study is to evaluate the corrosion behavior of candidate canisters materials (304L/308L(I), 304L/308L(II), 316L/316L stainless steels) by U-bend tests in a simulated coastal atmospheric environment. The U-bend specimens were conducted by salt fog test with 3.5wt% synthetic sea salt at different temperatures and constant relative humidity of 40% for 1500 hours. According to the results of morphology observation, similar corrosion behavior was observed on three different materials at 40, 60 and 80oC. Pitting coalescence was the major corrosion behavior on the base metal and interdendritic corrosion and pitting coalescence were the primary corrosion behavior on the weld metal. Based on the calculation of corroded area, the percentage of corroded area increased significantly at 40 and 60oC as the test duration increased, whereas it was slightly expanded at 80oC. Moreover, the depth of pit up to more than 60μm were measured on the base metal of 316L/316L SS specimens at three different temperatures.