Localized Corrosion Susceptibility Of Alloy 22 In Na-K-Cl_NO3 Brines At 110 To 150?C
Electrochemical cyclic potentiodynamic polarization experiments were conducted to assess crevice corrosion of Alloy 22 in de-aerated aqueous solutions of chloride and nitrate salts of potassium and sodium in the temperature range 110-150 C. The tests were run in neutral and slightly acidic aqueous solutions. The Alloy 22 specimens were multiple creviced weld prisms. No evidence of crevice corrosion was observed in the range 125-150 C. In the 120 to 160 C temperature range, the anionic concentration of stable aqueous solutions is dominated by nitrate relative to chloride. At nominally 120 C, the minimum nitrate to chloride ratio is about 4.5, and it increases to about 22 at nominally 155 C. The absence of localized corrosion susceptibility in these solutions is attributed to the known inhibiting effect of the nitrate anion. Aqueous solution chemistry studies indicate that nitrate to chloride ratios of less than 0.5 are possible for temperatures up to nominally 116 C. At 110 C, aqueous solutions can have dissolved chloride well in excess of nitrate. Localized corrosion was observed at nitrate to chloride ratios up to 1.0, the highest ratio tested. The extent of localized corrosion was confined to the crevice region of the samples, and was limited for nitrate to chloride ratios greater than or equal to 0.3.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 894340
- Report Number(s):
- UCRL-PROC-220367; TRN: US0700143
- Resource Relation:
- Conference: Presented at: International High Level Radioactive Waste Management, Las Vegas, NV, United States, Apr 30 - May 04, 2006
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALLOYS
AQUEOUS SOLUTIONS
BRINES
CHEMISTRY
CHLORIDES
CORROSION
CREVICE CORROSION
NITRATES
POLARIZATION
POTASSIUM
PRISMS
RADIOACTIVE WASTE MANAGEMENT
SODIUM