Denting of Inconel 600 steam generator tubes in pressurized water reactors
Rapid, localized corrosion of carbon steel tube support plates (TSP) has led to cases of denting of steam generator tubes, due to the pressure of corrosion products formed in crevices between the tubes and TSP holes. The corrosion product is mainly magnetite (Fe/sub 3/O/sub 4/), formed in ''run-away'' fashion as a result of local chemistry changes when an extended operation with phosphate (PO/sub 4/) treatment of the secondary coolant is followed by an all volatile treatment (AVT). The rate of the ''run-away'' magnetite formation, and therefore, the extent of damage will probably vary with the amounts of the harmful chemicals present and with temperature. Leaky condensers are felt to be responsible for the presence of Cl/sup -/ ions, and for the observation that denting is more extensive in plants with salt water cooled condensers. It is possible that thermal cycles assist the denting process, both by mechanical and chemical ratchetting mechanisms. Recommendations are presented concerning the continued operation of plants with observed denting.
- Research Organization:
- Brookhaven National Lab., Upton, N.Y. (USA)
- DOE Contract Number:
- EY-76-C-02-0016
- OSTI ID:
- 7247027
- Report Number(s):
- BNL-NUREG-21914
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
210200* -- Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
ALLOYS
BOILERS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CORROSION
CORROSION PRODUCTS
DEFORMATION
INCONEL 600
INCONEL ALLOYS
IRON ALLOYS
NICKEL ALLOYS
NICKEL BASE ALLOYS
NIOBIUM ALLOYS
PWR TYPE REACTORS
REACTORS
STEAM GENERATORS
TUBES
VAPOR GENERATORS
WATER CHEMISTRY
WATER COOLED REACTORS
WATER MODERATED REACTORS