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

Destructive examination of tube R31C66 from the Ginna Nuclear Plant steam generator

Technical Report ·
OSTI ID:5504447
;  [1]
  1. Combustion Engineering, Inc., Windsor, CT (USA). ABB Combustion Engineering Nuclear Power

Metallographic and microanalytical examinations have been performed on a section of hot leg tube R31C66 from steam generator A of the R.E. Ginna Nuclear Power Plant. Field ECT had indicated the presence of an ID initiated axial flaw in the tubesheet roll transition of the NiCrFe Alloy 600 tube. Destructive examination confirmed the presence of an intergranular stress corrosion crack at the roll transition. The examination could not indicate whether the IGSCC initiated at the ID or the OD and propagated throughwall. Phosphorous and iron were present on the crack face suggesting the crack initiated from the OD and propagated throughwall. The aspect ratio of the crack, (length to depth ratio), however, suggests that the crack initiated from the ID and propagated throughwall. Because of the conflicting evidence, the actual mechanism resulting in the throughwall defect could not be defined. Shallow IGA was present in the tubesheet crevice region of the tube, probably as a result of caustic conditions in the crevice. Deposits on the OD of the tube were up to 8 mils thick and may be affecting heat transfer. There were no significant ID deposits on the tube. 6 refs.

Research Organization:
Electric Power Research Inst., Palo Alto, CA (United States); Combustion Engineering, Inc., Windsor, CT (United States). ABB Combustion Engineering Nuclear Power
Sponsoring Organization:
EPRI; Electric Power Research Inst., Palo Alto, CA (United States)
OSTI ID:
5504447
Report Number(s):
EPRI-NP-7371-M
Country of Publication:
United States
Language:
English