Corrosion experience with the secondary side of steam generators in France

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:409734

Gelpi, A ^[1]; Cattant, F ^[2]; Vaillant, F ^[3]

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1. Framatome, Paris la Defense (France)
2. EPRI/NMAC, Charlotte, NC (United States)
3. EDF/DER Les Renardieres, Moret sur Loing (France)

In French plants, OD corrosion is mainly found in three areas: (1) under the top of the tubesheet; (2) above the tubesheet in the sludge pile; (3) at the tube support plate intersections. The cracking under the top of the tubesheet, is circumferential and tubes have to be plugged soon as cracks are detected. The reasons for this cracking are poorly understood; however only small number of steam generators is concerned by this cracking. Above the tubesheet in the sludge pile, cracks are longitudinal and mixed with IGA. The kinetics of this corrosion is assessed in the framework of the leak before break maintenance policy which leads to a reduction in the number of tubes requiring plugging. Moreover, sludge can be partially remove by chemical cleaning and sludge lancing. Corrosion at the tube support elevations is the main cause of tube plugging and was thin, reason for the replacement of the Saint Laurent B1 steam generators. Investigations air understanding this phenomenon have been based either on the working hypothesis that corrosion due to a caustic environment or focused on a detailed knowledge of the deposits and the reactions. Results obtained from these different investigations are presented in this conference.

• OSTI ID: 409734
• Report Number(s): CONF-9510292--; ISBN 1-57570-008-4
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
CORROSION
CRACK PROPAGATION
FOULING
FRANCE
INTERGRANULAR CORROSION
NUCLEAR POWER PLANTS
PWR TYPE REACTORS
SAINT LAURENT-B1 REACTOR
SECONDARY COOLANT CIRCUITS
STEAM GENERATORS
WATER CHEMISTRY