Microstructural characterization of alloy 690Tt exposed to Pb-containing caustic solutions

G. B. Mazzei, J. Duff, M. G. Burke, F. Scenini, G. Meredith, T. Horner

Research output: Contribution to conferencePaperpeer-review

Abstract

Lead-induced stress corrosion cracking (PbSCC) is one of the secondary side degradation phenomena that has occurred in the steam generator (SG) of pressurized water reactors (PWR). In order to reproduce the conditions where PbSCC develops, C-rings of Alloy 690TT were loaded to the yield stress or to 6% plastic deformation and exposed at 315°C to caustic solutions (pHRT = 13.7) containing 1000 ppm of PbO. Two different surface finishes (as-received, with a local surface deformation, and Oxide Polishing Suspension) were tested to investigate the effect of the surface deformed layer on the SCC initiation propensity. Advanced electron microscopy (SEM, FIB and ATEM) examinations of the oxidized surface revealed that the surface-deformed layer promoted the formation of a protective passive layer, which, in turn, retarded crack formation. The role of stress, surface condition and environmental interactions on PbSCC are also discussed.

Original languageEnglish
Pages1174-1180
Number of pages7
Publication statusPublished - 2019
Event19th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, EnvDeg 2019 - Boston, United States
Duration: 18 Aug 201922 Aug 2019

Conference

Conference19th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, EnvDeg 2019
Country/TerritoryUnited States
CityBoston
Period18/08/1922/08/19

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