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U.S. Department of Energy
Office of Scientific and Technical Information

Examination of Kewaunee steam generator tubes R4C81 and R11C9

Technical Report ·
OSTI ID:5651610
; ;  [1]
  1. Westinghouse Electric Corp., Pittsburgh, PA (USA)

Two mill annealed Alloy 600 steam generator tubes were pulled from the hot leg side of Steam Generator B at the Kewaunee Nuclear Power Plant to investigate eddy current indications at and just above the tubesheet top for Tube R4-C81 and within the unexpanded tubesheet crevice region of Tube R11-C9. The tubes were examined by nondestructive and destructive examination techniques. Both tubes had a long, axial crack within the tubesheet crevice region. The cracking was caused by secondary side intergranular stress corrosion (IGSCC). The crack morphology also had some three dimensional grain boundary degradation or intergranular attack (IGA) characteristics. In addition, Tube R4-C81 had a large network of predominately axial IGSCC with some minor circumferential IGSCC at and just above the tubesheet top region. The IGSCC had strong IGA characteristics. From analyses performed on OD deposits and crack fracture face oxide films, it was concluded that an alkaline crevice environment was associated with the stress corrosion. 4 refs., 5 figs.

Research Organization:
Electric Power Research Inst., Palo Alto, CA (United States); Westinghouse Electric Corp., Pittsburgh, PA (United States)
Sponsoring Organization:
EPRI; Electric Power Research Inst., Palo Alto, CA (United States)
OSTI ID:
5651610
Report Number(s):
EPRI-NP-7370-M
Country of Publication:
United States
Language:
English