Abstract
Secondary side corrosion cracking of steam generator tubes in Mill Annealed Alloy 600 occurs in flow-restricted areas where impurities get concentrated under heat flux. During spring 2009, eddy current test showed a circumferential indication (tube support plate elevation) in Bugey-3 unit for the first time on French nuclear plants in which very little PbO was detected in deposits in the late 80’s after 67000h of service. The corresponding tube was therefore removed. IGSCC cracks and outer oxides layers formed on these pulled tubes were examined by ATEM. The results are compared to previous ones obtained on a tube pulled out from another unit (Dampierre-4) where Pb was detected during ATEM observations and not suspected to be at the origin of IGSCC. Then, results are compared to those obtained on specimen tested in laboratory environment all leading to SCC rates comparable to secondary side corrosion cracking rates observed in the field. The oxides formed were compared to identify the typical environment responsible for the degradation observed on the pulled tubes. It appears that the best laboratory environment reproducing oxides morphology observed on the selected pulled tubes was a NaOH with Pb environment even thought Si pollution was sometimes detected in outside oxides layer.
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References
P. Ollar, A. Stutzmann, and F. Nordmann, “Measurement of hideout return”, EPRI Expert meeting on secondary side corrosion, Airlie House (VA) USA, October 9–13, 1995.
F. Cattant, M. Dupin, B. Sala, and A. Gelpi, “Analysis of deposits and underlying surfaces on the secondary side of pulled tubes from a French plant”, Contribution of Materials Investigation to the Resolution of Problems Encountered in Pressurized Water Reactors, International Symposium, Proceedings of Fontevraud III International Symposium, September 1994.
B. Sala, and al., “Analysis of the deposits and surface layer on pulled tubes from PWR French steam generators”, Eurocorr ’96, Nice, September 24–26, 1996.
J.M. Boursier, and al., “Secondary side corrosion of French PWR steam generator tubing: Contribution of surface analyses to the understanding of the degradation process”, Proceedings of the 9th International Conference on Environmental Degradation of Materials in Nuclear Power Systems — Water Reactors, Newport Beach (CA), USA, TMS, August 1999.
B. Sala, and al., “Complementary investigations concerning the analysis of the deposits and underlying surfaces observed on French PWR steam generator pulled tubes”, Proceedings of Fontevraud IV International Symposium, September 1998.
E.M. Pavageau, and al., “Secondary Side Corrosion Modeling of Alloy 600 for steam generator tubes based on laboratory tests in sulfate environments”, Proceedings of the 10th International Conference on Environmental Degradation of Materials in Nuclear Power Systems — Water Reactors, Lake Tahoe (NV), USA, TMS, August 2001.
F. Vaillant, and al., “Duplication in laboratory of deposits, films and IGA/SCC damage observed on pulled steam generator tubes”, Proceedings of the 10th International Conference on Environmental Degradation of Materials in Nuclear Power Systems — Water Reactors, Lake Tahoe (NV), USA, TMS, August 2001.
F. Vaillant, and al., “Modeling the secondary side corrosion of tubing: a help to the maintenance policy of PWR Steam Generators”, Proceedings of the ninth International conference on environmental degradation of materials in nuclear power systems — Water reactors, Newport Beach (CA), USA, TMS, August 1999, p. 695.
O. de Bouvier, and al., “Nickel alloy stress corrosion cracking in neutral and lightly alkaline sulfate environments”, Proceedings of the 9th International conference on environmental degradation of materials in nuclear power systems — Water reactors, Newport Beach (CA), USA, TMS, August 1999.
O. de Bouvier, and al., “Stress corrosion cracking on nickel alloys in complex (liquid and vapor) environments”, Proceedings of the 12th International Conference on Environmental Degradation of Materials in Nuclear Power Systems — Water Reactors, Salt Lake City (UA), USA, TMS, August 2005.
L. Legras, and al., “On the microstructure of Alloy 600 SCC cracks observed by TEM on pulled tubes from a PWR Steam Generator and on primary and secondary laboratory environments specimens”, Proceedings of Fontevraud VI International Symposium, September 2006.
Y. Thebault, and al,. “Experience of steam generator tube examinations in the hot laboratory of EDF: Analysis of recent events concerning the secondary side”, Fontevraud VII International Symposium, September 2010.
F. Vaillant, D. Buisine, and B. Prieux, “Comparative Behavior of Alloys 600, 690 and 800 in Caustic Environments”, Proceedings of the 7th International Conference on Environmental Degradation of Materials in Nuclear Power Systems — Water Reactors, Breckenridge (CO), USA, TMS, August 1995.
E. M. Pavageau, and al., “Coupling service crevice chemistry corrosion model based in laboratory: a first application to the analysis of secondary side corrosion in service”, Proceedings of international conference water chemistry in nuclear reactor systems, Avignon, 2002.
L. Thomas, S. Bruemmer, and A. McIlree, “Lead observations at crack tips in alloy 600 steam generator tubing”, presented at the Workshop of Effects of Pb and S on the Performance Of Secondary Side Tubing of Steam Generator in PWRs, Argonne Natinal Labooratory, IL, May 2005.
R.W. Staehle, “Clues and issues in the SCC of high nickel alloys associated with dissolved”, Proceedings of the 12th International Conference on Environmental Degradation of Materials in Nuclear Power Systems — Water reactors, Salt lake city (Utah), USA, TMS, August 2005.
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Legras, L., de Bouvier, O., Delabrouille, F., Fargeas, E., Miloudi, S., Thebault, Y. (2011). On the Microstructure of Alloy 600 SCC Cracks Observed by TEM on PWR SG Pulled Tubes and on Laboratory Specimens. In: Busby, J.T., Ilevbare, G., Andresen, P.L. (eds) Proceedings of the 15th International Conference on Environmental Degradation of Materials in Nuclear Power Systems — Water Reactors. Springer, Cham. https://doi.org/10.1007/978-3-319-48760-1_61
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DOI: https://doi.org/10.1007/978-3-319-48760-1_61
Publisher Name: Springer, Cham
Online ISBN: 978-3-319-48760-1
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