[en] The effects of gamma-ray irradiation on corrosion resistance have been studied about austenitic stainless steel as one of the candidate alloys for high-level radioactive waste canisters. The double U-bend specimens were used for the purpose of stress corrosion cracking (SCC) test on Type 304 ss and Type 309S ss. Sensitized Type 304 ss and Type 309S ss specimens were encapsuled respectively in capsules with a cubic granite and simulated groundwater. Test specimens were also encapsuled in a capsule with only humid bentonite in order to simulate the disposal environments. Capsules were irradiated with ¹³⁷Cs source at WASTEF and with spent fuel in JMTR. The results showed that sensitized Type 304 ss have susceptibilities to SCC and sensitized 309S ss have not susceptibilities in the simulated disposal condition. On the other hand, no specimen was susceptible to SCC in deionized water even with gamma-ray irradiation. (author)