This paper describes the observed occurrences of circumferential cracks in alloy 600 tubes in nuclear plant steam generators. The causes of circumferential cracks are discussed and the conditions under which they develop are described in terms of material condition, stress, and environment. Inspection issues related to circumferential cracks are discussed, and areas for improvement are reviewed. Management issues with regard to development of inspection methods, alternate repair criteria, and prediction of future occurrence of circumferential cracks are discussed.
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