The Effect of pH on Nickel Alloy SCC and Corrosion Performance

Morton, D.S. ; Hansen, M.

Lockheed Martin

关键词: Corrosion;    Coolants;    Crack Propagation;    Alloys;    08 Hydrogen;   

DOI  :  10.2172/821960
RP-ID  :  LM-02K093
RP-ID  :  AC12-00SN39357
RP-ID  :  821960

美国|英语

来源: UNT Digital Library

【 摘 要 】

Alloy X-750 condition HTH stress corrosion crack growth rate (SCCGR) tests have been conducted at 360 C (680 F) with 50 cc/kg hydrogen as a function of coolant pH. Results indicate no appreciable influence of pH on crack growth in the pH (at 360 C) range of {approx} 6.2 to 8.7, consistent with previous alloy 600 findings. These intermediate pH results suggest that pH is not a key variable which must be accounted for when modeling pressurized water reactor (PWR) primary water SCC. In this study, however, a nearly three fold reduction in X-750 crack growth rate was observed in reduced pH environments (pH 3.8 through HCl addition and pH 4-5.3 through H{sub 2}SO{sub 4} addition). Crack growth rates did not directly correlate with corrosion film thickness. In fact, 10x thicker corrosion films were observed in the reduced pH environments.