Remedial methods for intergranular attack of alloy 600 tubing. Volume 2. Additives and test plants for remedial methods. Final report
A literature search was conducted to find potential remedies for caustic-produced intergranular attack (IGA) on alloy 600 tubes in the tube-tube crevice region of steam generators in a few PWR plants. Caustic-producing alkalies Na and K are concentrated on the tube side as phosphates and silicates in multi-component deposits which have accumulated in crevices in these plants. Off-line flushing of crevices, using low temperature water soak and drain cycles, is recommended as reasonably effective and the safest method of removing the alkalies. For a thorough cleaning of crevices, chelant-based formulations have been identified to remove the major components of deposits, namely, Fe/sub 3/O/sub 4/, Cu/CuO, and Ca-salts. Conventional inorganic or organic inhibitors were considered not suitable for use, because of their poor stability under steam generator crevice conditions and possible adverse effects on tubes and ancillary plant components. However, boric acid which is used frequently to combat other forms of corrosion in PWR plants, was identified as a potentially useful additive to the feed water or to the soak water for neutralizing caustic and also inhibiting IGA. 63 refs., 42 figs., 19 tabs.
- Research Organization:
- Battelle Columbus Labs., OH (USA)
- OSTI ID:
- 5579829
- Report Number(s):
- EPRI-NP-4635-Vol.2; ON: TI86920388; TRN: 86-021994
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
INCONEL 600
CRACK PROPAGATION
CREVICE CORROSION
INTERGRANULAR CORROSION
REACTOR MATERIALS
STRESS CORROSION
PWR TYPE REACTORS
SECONDARY COOLANT CIRCUITS
STEAM GENERATORS
TUBES
CORROSION INHIBITORS
MATERIALS TESTING
OXIDATION
WATER CHEMISTRY
ALLOYS
BOILERS
CHEMICAL REACTIONS
CHEMISTRY
CHROMIUM ALLOYS
COOLING SYSTEMS
CORROSION
ENERGY SYSTEMS
INCONEL ALLOYS
IRON ALLOYS
MATERIALS
NICKEL ALLOYS
NICKEL BASE ALLOYS
NIOBIUM ALLOYS
REACTOR COMPONENTS
REACTOR COOLING SYSTEMS
REACTORS
TESTING
VAPOR GENERATORS
WATER COOLED REACTORS
WATER MODERATED REACTORS
210200* - Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
360105 - Metals & Alloys- Corrosion & Erosion
360103 - Metals & Alloys- Mechanical Properties