The safe and reliable operation of pressurized water reactors (PWRs) depends on the integrity of structural material. In particular, the failure of steam generator (SG) tubes on the secondary side is one of the major concerns of operating nuclear power plants. To establish remediation techniques and manage damage, it is necessary to articulate the mechanism through which various impurities affect the SG tubes. This research aims to understand the effect of impurities (e.g., S, Pb, and Cl) on the stress corrosion cracking of Alloy 600 and 690.