EFFECTS OF GAMMA-RAY IRRADIATION ON CRACK-GROWTH OF SENSITIZED TYPE-304 STAINLESS-STEEL IN 288-DEGREES-C WATER

Propagation of intergranular stress corrosion cracking (IGSCC) in sens itized type 304 (UNS S30400) stainless steel (SS) in 288-degrees-C wat er was enhanced by gamma-ray irradiation with a flux of 2.3 x 10(3) co ul/kg-h (approximately 1 x 10(7) R/h). Crack growth rates under irradi ation were up to twice as large as those in unirradiated water. The ac celeration was attributed to hydrogen peroxide (H2O2) formed in water by irradiation. Crack growth rates depended on the concentration of ox ygen (O2) + 1/2 (H2O2) in the water. Injection of hydrogen (H-2) into water prevented crack propagation under gamma-ray irradiation because oxidizing species, such as H2O2 and O2, recombined with the injected H -2.