Effect of Chloride Transients on Crack Growth Rates in Low Alloy Steels in BWR Environments
The objective of this study was to quantify the effect of chloride transients on stress corrosion cracking of pressure vessel low alloy steels. Two heats of reactor pressure vessel steel were evaluated at various chloride concentrations in both NWC and HWC environments. The tests showed that low alloy steels can exhibit a delayed cracking response during a chloride transient. The delayed response is attributed to the concentrating and dilution processes of anionic impurities inside the crack. The crack can maintain its original growth rate for a certain period after the chemistry change. The effects of chloride concentration, stress intensity factor (K) and periodic load cycling on the crack incubation and growth in low alloy steel will be discussed. The results from this work will provide a direct input to development of a crack growth model for low alloy steels, water chemistry guidelines and effects of chloride transients on crack growth.
KeywordsPressure vessel low alloy steel Stress corrosion cracking Chloride Boiling water reactor Crack growth Memory effect
This research is sponsored by Boiling Water Reactor Vessel and Internals Program, Electric Power Research Institute. Authors thank Dr. Peter Andresen for many helpful discussion.
- 2.F.P. Ford, P.L. Andresen, Stress corrosion cracking of low alloy steels in 288C water (NACE, New Orleans, 1989)Google Scholar
- 3.F.P. Ford, D.F. Taylor, P.L. Andresen, R.G. Ballinger, environmentally-controlled cracking of stainless and low-alloy steels in light-water reactor environments, 2006Google Scholar
- 4.EPRI, BWRVIP-190 Revision 1: BWR Vessel and Internals Project, Volume 1: BWR Water Chemistry Guidelines—Mandatory, Needed, and Good Practice Guidance, EPRI, Palo Alto, CA, 2014Google Scholar
- 5.H.P. Seifert, S. Ritter, Research and service experience with environmentally-assisted cracking of carbon and low-alloy steels in high-temperature water (Stockholm, Sweden, 2006)Google Scholar
- 7.X.Y. Lou, P.L. Andresen, BWRVIP-292: Effects of Low Level Chloride on Stress Corrosion Cracking of Low Alloy Pressure Vessel Steels in BWR Environments, 3002005622 (EPRI, Palo Alto, CA, USA, 2015)Google Scholar
- 8.X.Y. Lou, P.L. Andresen, T.G. Lian, R. Pathania, Effect of ppb Levels of Chloride on the Stress Corrosion Cracking of Pressure Vessel Steel (Canadian Nuclear Society, Ottawa, Ontario, Canada, 2015)Google Scholar
- 13.C. Marks, D. Macdonald, W. Coulson, Materials Reliability Program Reactor Vessel Head Boric Acid Corrosion Testing (MRP-165) (Electric Power Research Institute, Palo Alta, 2005)Google Scholar