Effect of hydrogen water chemistry on ultrasonic response for intergranular stress corrosion cracking
Hydrogen water chemistry (HWC) is one of the approaches to control BWR water chemistry, which reduces the oxidizing power of the water to a level at which intergranular stress corrosion cracking (IGSCC) (initiation and growth) is effectively suppressed. In this treatment, hydrogen gas is injected into the feedwater to lower the electrochemical corrosion potential (ECP) of stainless steel components. The objective of this work is to experimentally document the effect of HWC on IGSCC detectability. Two pipe samples (pipe sectors B, C) were fabricated from a 12-inch Type 304 stainless steel pipe weldment containing a range of circumferential and axial cracks induced by the Creviced Piped Test. Initial characterization of IGSCC was performed for both pipes by UT and PT prior to application of HWC treatments. For each sample two separate UT methods were used. One was a manual technique that represents field practice, and the other was a laboratory technique that produced ultrasonic images of each crack. Both samples were subjected to a normal BWR water chemistry (NWC) for 168 hours before the HWC treatments. After NWC, one IGSCC sample B was treated for a period of 500 hours with a normal HWC condition (HWC-1) having electrochemical potential (ECP) value of about {minus}0.60 volts (SHE) with Pt reference electrode, water dissolved oxygen content of less than 20 ppb, and water conductivity of less than 0.3 micro-S/cm. The other IGSCC sample C was treated for a period of 500 hours with an off-normal HWC condition (HWC-2) having ECP value of about {minus}0.30 volts (SHE) with Pt reference electrode, and water conductivity of less than 0.3 micro-S/cm. (same as HWC-1). After the HWC treatments, the two IGSCC pipe samples were ultrasonically characterized in the exact manner that was done in the initial characterization to determine if there were any noticeable changes in the UT response of the cracks as indicated by their sizes and signal amplitudes.
- Research Organization:
- Electric Power Research Inst., Palo Alto, CA (United States); Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)
- Sponsoring Organization:
- EPRI; Electric Power Research Inst., Palo Alto, CA (United States)
- OSTI ID:
- 5246509
- Report Number(s):
- EPRI-TR-100649
- Country of Publication:
- United States
- Language:
- English
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36 MATERIALS SCIENCE
360105 -- Metals & Alloys-- Corrosion & Erosion
ACOUSTIC TESTING
ALLOYS
AUSTENITIC STEELS
BWR TYPE REACTORS
CHEMICAL REACTIONS
CHEMISTRY
CHROMIUM ALLOYS
CHROMIUM-NICKEL STEELS
CORROSION
CORROSION RESISTANT ALLOYS
CRACKS
CRYSTAL STRUCTURE
ELEMENTS
ENRICHED URANIUM REACTORS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HIGH ALLOY STEELS
HYDROGEN
INTERGRANULAR CORROSION
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
MATERIALS TESTING
MICROSTRUCTURE
NICKEL ALLOYS
NONDESTRUCTIVE TESTING
NONMETALS
PIPES
POWER REACTORS
REACTOR COMPONENTS
REACTORS
STAINLESS STEEL-304
STAINLESS STEELS
STEEL-CR19NI10
STEELS
STRESS CORROSION
TESTING
THERMAL REACTORS
ULTRASONIC TESTING
WATER CHEMISTRY
WATER COOLED REACTORS
WATER MODERATED REACTORS