Analysis of cracked core spray injection line piping from the Quad Cities Units 1 and 2 boiling water reactors
Elbow assemblies and adjacent piping from the loops A and B core spray injection lines of Quad Cities Units 1 and 2 Boiling Water Reactors have been examined in order to determine the nature and causes of coolant leakages and flaw indications detected during hydrostatic tests and subsequent ultrasonic inspections. The elbow assemblies were found to contain multiple intergranular cracks in the weld heat-affected zones. The cracking was predominantly axial in orientation in the forged elbow and wedge components, whereas mixed axial and circumferential cracking was seen in the wrought piping pieces. In at least two instances, axial cracks completely penetrated the circumferential weld joining adjacent components. Based upon the observations made in the present study, the failures were attributed to intergranular stress corrosion cracking caused by the weld-induced sensitized microstructure and residual stresses present; dissolved oxygen in the reactor coolant apparently served as the corrosive species. The predominantly axial orientation of the cracks present in the forged components is believed to be related to the banded microstructure present in these components. The metallographic studies reported are supplemented by x-radiography, chemical analysis and mechanical test results, determinations of the degree of sensitization present, and measurements of weld metal delta ferrite content.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 5518297
- Report Number(s):
- ANL-83-99; ON: DE84004888
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
QUAD CITIES-1 REACTOR
CORE SPRAY SYSTEMS
QUAD CITIES-2 REACTOR
CHEMICAL ANALYSIS
CRACKS
DEFECTS
INTERGRANULAR CORROSION
LEAKS
MECHANICAL TESTS
METALLOGRAPHY
PIPE JOINTS
PIPES
STRESS CORROSION
X-RAY RADIOGRAPHY
BWR TYPE REACTORS
CHEMICAL REACTIONS
CORROSION
ECCS
ENGINEERED SAFETY SYSTEMS
ENRICHED URANIUM REACTORS
INDUSTRIAL RADIOGRAPHY
JOINTS
MATERIALS TESTING
POWER REACTORS
REACTOR PROTECTION SYSTEMS
REACTORS
TESTING
WATER COOLED REACTORS
WATER MODERATED REACTORS
210100* - Power Reactors
Nonbreeding
Light-Water Moderated
Boiling Water Cooled