Understanding the Mechanism of Stress Corrosion Cracking Resistance in Stainless Steel Welds Subjected to Laser Shock Peening without Coating for Nuclear Canister Applications

The stainless-steel weld joints of dry storage canisters (DSC) used for storing spent nuclear fuel are highly susceptible to stress corrosion cracking (SCC). This is a serious safety concern in the nuclear industry as it releases nuclear radiation from interim storage locations. To mitigate this issue, the present study utilizes laser shock peening without protective coating (LSPwC) on austenitic stainless steel (ASS) weld joints. LSPwC is performed on the ASS weld joints with two intensities (7 and 9 GW/cm 2 ) and two overlap ratios (30 and 50%). The results showed that LSPwC induced high magnitude and in-depth residual compressive stress (RCS), work-hardened layer, and plastic strain in the weld joints. The remarkable enhancement in SCC resistance of LSPwC’ed ASS weld joints can be attributed to grain refinement and RCS. The underlying mechanism of improved SCC resistance of the LSPwC’ed ASS weld joints was elucidated using x-ray diffraction (XRD) and scanning electron microscope. These findings demonstrate that LSPwC is a viable surface modification technique to mitigate the SCC in DSCs.