Operating experience with Westinghouse steam generators

Journal Article · Mon Mar 01 04:00:00 EST 1976 · Nucl. Technol., v. 28, no. 3, pp. 356-373

OSTI ID:4092234

Fletcher, W D; Malinowski, D D

Service exposure has been accrued in 66 steam generators tubed with Inconel-600. Localized corrosion coincident with sludge deposition in low flow- velocity zones has been observed. Intergranular cracking has been attributed to stress-assisted caustic corrosion resulting from hydrolysis of condenser inleakage contaminants or sodium phosphate reactions with feedwater corrosion products. Wall thinning or wastage is attributed to the formation of high- concentration sodium phosphate solutions under the sludge blanket. The resistance of Inconel-600 to these corrosion mechanisms is comparable or superior to that of other candidate tube materials. The experience gathered points strongly to environmental and thermal/hydraulic factors rather than materials considerations as the predominant influence on the occurrence of localized corrosion. Mechanical modifications designed to reduce the number of tubes in zones of low flow-velocity are being installed into operating units; current production units have incorporated design features including a flow distribution baffle to improve the thermal/hydraulic conditions over prior models. Rigorous control of feedwater impurities is being applied to reduce the probability of creating a corrosive environment in the steam generators. (auth)

• Research Organization: Westinghouse Electric Corp., Pittsburgh
• NSA Number: NSA-33-027969
• OSTI ID: 4092234
• Journal Information: Nucl. Technol., v. 28, no. 3, pp. 356-373, Journal Name: Nucl. Technol., v. 28, no. 3, pp. 356-373; ISSN NUTYB
• Country of Publication: United States
• Language: English

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