SUSCEPTIBILITY OF SENSITIZED TYPE-304 STAINLESS-STEEL TO INTERGRANULAR STRESS-CORROSION CRACKING IN SIMULATED BOILING-WATER REACTOR ENVIRONMENTS

Slow strain rate tests (SSRT) were conducted to evaluate the mitigatin g effect of hydrogen water chemistry (HWC) on intergranular stress cor rosion cracking (IGSCC) of sensitized type 304 (UNS S30400) stainless steel (SS) used for in-reactor components of boiling-water reactors (B WR). The in-reactor environment was simulated by controlling water che mistry parameters such as dissolved oxygen (DO), dissolved hydrogen (D H), hydrogen peroxide (H2O2), and corrosion potential (E-corr). Effect s of the products of water radiolysis on SCC behavior mere examined in the presence of a gamma-radiation field. IGSCC susceptibility of sens itized type 304 SS decreased with decreasing concentrations of DO and H2O2, which suggested IGSCC of sensitized type 304 SS could be mitigat ed even in the in-reactor environment under HWC conditions. IGSCC susc eptibility clearly was dependent upon E-corr, as controlled by the con centrations of stable radiolytic products (e.g., O-2, H2O2, and H-2). regardless of short-lived radicals generated by gamma-radiation.