Environmental cracking of Alloy 600 in BWR environments

Technical Report · Fri Mar 01 04:00:00 EST 1991

OSTI ID:6118258

Ljungberg, L G

Alloy 600 may be sensitized to intergranular stress corrosion cracking (IGSCC) in both BWR normal water chemistry (NWC) and in hydrogen water chemistry (HWC). Carbide precipitation causes chromium depleted grain boundaries, which are susceptible to IGSCC in NWC but not in HWC. The mechanism for chromium depletion is complex due to the existence of two chromium carbides. Segregated phosphorous enhances IGSCC of Alloy 600 with chromium depleted grain boundaries in NWC. Under all other conditions phosphorous seems harmless. Grain boundary segregated sulfur is suspect of enhancing IGSCC in both NWC and HWC, but no verifying tests have been performed. Boron and nitrogen have a strong tendency to segregate to grain boundaries in Alloy 600, but seem to be harmless. Only few crack propagation data relevant to BWR conditions exist for Alloy 600. The paper describes mechanisms for sensitization, stress corrosion cracking, and crack propagation rates. 94 refs., 21 figs., 1 tab.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (USA); ABB Atom AB, Vaesteraas (Sweden)
• Sponsoring Organization: EPRI; Electric Power Research Inst., Palo Alto, CA (USA)
• OSTI ID: 6118258
• Report Number(s): EPRI-NP-7199
• Country of Publication: United States
• Language: English

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ALLOYS
ALUMINIUM ADDITIONS
ALUMINIUM ALLOYS
BORON
BWR TYPE REACTORS
CARBIDES
CARBON COMPOUNDS
CHEMICAL REACTIONS
CHEMISTRY
CHROMIUM ALLOYS
CHROMIUM CARBIDES
CHROMIUM COMPOUNDS
CORROSION
CORROSION RESISTANT ALLOYS
CORROSIVE EFFECTS
CRACK PROPAGATION
CRYSTAL STRUCTURE
ELEMENTS
EMBRITTLEMENT
FATIGUE
GRAIN BOUNDARIES
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HYDROGEN
HYDROGEN EMBRITTLEMENT
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INCONEL 690
INCONEL ALLOYS
INTERGRANULAR CORROSION
IRON ALLOYS
MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NICKEL ALLOYS
NICKEL BASE ALLOYS
NIMONIC
NITROGEN
NONMETALS
PHOSPHORUS
PRECIPITATION
REACTORS
SEMIMETALS
SEPARATION PROCESSES
STRESS CORROSION
SULFUR
TITANIU
TITANIUM ADDITIONS
TITANIUM ALLOYS
TRANSITION ELEMENT COMPOUNDS
WATER CHEMISTRY
WATER COOLED REACTORS
WATER MODERATED REACTORS