Examination of Trojan steam generator tubes. Volume 1, Examination results: Final report

Technical Report · Sun Nov 01 04:00:00 EST 1992

OSTI ID:10120639

Magee, T P; Hall, J F ^[1]

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1. ABB/Combustion Engineering, Inc., Windsor, CT (United States)

Nondestructive and destructive examinations were performed on sections of ten tubes pulled from Trojan in 1991. Sections of tubing from the 1986 examination were also re-examined. Objectives were to characterize the depths and types of defects present at the tube support plate intersections (TSPs), determine the burst pressure of the TSPs, determine the ability of various field eddy current test techniques to characterize the defects, characterize any defects occurring near the top of the tubesheet and to characterize deposits on the OD of the tube. The TSPs had burst pressures in excess of the NRC requirement of 3 times normal operating primary to secondary water pressure differential. The defects, found at all TSPs examined, were a series of tight OD initiated, axially orientated intergranular stress corrosion cracks (IGSCC), bound by the crevice formed between the tube and the support plate. One tube had defects that were a mixture of intergranular attack and IGSCC. Eddy current techniques were found to be an effective method of assessing tube integrity. Maximum penetration in each TSP was 49 to 98% throughwall. Cracking was attributed to caustic in crevices. No defects were found outside the TSP crevice. Deposits, composed primarily of magnetite and copper, had far lower levels of chloride and sulfate than in 1986.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (United States); ABB Combustion Engineering, Inc., Windsor, CT (United States)
• Sponsoring Organization: Electric Power Research Inst., Palo Alto, CA (United States)
• OSTI ID: 10120639
• Report Number(s): EPRI-TR--101427-Vol.1; ON: UN93005899
• Country of Publication: United States
• Language: English

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AUGER ELECTRON SPECTROSCOPY
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