The Effect of pH on Nickel Alloy SCC and Corrosion Performance
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.
- Research Organization:
- Lockheed Martin Corporation, Schenectady, NY 12301 (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC12-00SN39357
- OSTI ID:
- 821960
- Report Number(s):
- LM-02K093
- Country of Publication:
- United States
- Language:
- English
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