Electrochemical potential monitoring in the PWR secondary cycle of St. Lucie 2. Final report
- NWT Corporation, San Jose, CA (United States)
Reducing conditions are necessary in PWR steam generators to minimize local corrosion phenomena, e.g., secondary side intergranular attack/stress corrosion cracking (IGA/SCC). To achieve this goal, the electrochemical potential (ECP) should be maintained below the threshold at which these corrosion mechanisms occur. Ideally, in-situ ECP measurements in the steam generator would allow for monitoring and controlling oxidant ingress to maintain the desired reducing conditions. Unfortunately, such measurements are difficult to implement. Nevertheless, oxidant ingress can be monitored and controlled via ECP measurements in the high pressure feedwater. A feedwater ECP monitoring system was installed at the St. Lucie 2 PWR of Florida Power and Light Company to assess this approach. Variations in feedwater ECP and corrosion product transport were monitored as chemistry was varied. Alloy 600 ECP was shown to depend on the feedwater hydrazine/condensate dissolved oxygen ratio. Operation at a hydrazine/oxygen ratio above 6 was necessary to maintain a low ECP.
- Research Organization:
- Electric Power Research Inst., Palo Alto, CA (United States); NWT Corp., San Jose, CA (United States)
- Sponsoring Organization:
- Electric Power Research Inst., Palo Alto, CA (United States)
- OSTI ID:
- 61079
- Report Number(s):
- EPRI-TR--104951
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
CORROSION PRODUCTS
CORROSION PROTECTION
DESIGN
ELECTRIC POTENTIAL
ELECTROCHEMICAL CORROSION
EXPERIMENTAL DATA
HYDRAZINE
INCONEL 600
LUCIE-2 REACTOR
MASS TRANSFER
MITIGATION
MONITORING
ON-LINE MEASUREMENT SYSTEMS
OXIDIZERS
PERFORMANCE
STEAM GENERATORS
WATER CHEMISTRY