Stress Corrosion Cracking and Localized Corrosion of Carbon Steel in Nitrate Solutions

The stress corrosion cracking (SCC) of carbon steel in nitrate-containing environments has been known for a long time and has become important in managing the integrity of aging underground radioactive waste storage tanks. This paper describes the latest research on the effect of environmental chemistry on localized corrosion and SCC of steel in nitrate-containing solutions, especially as it relates to radioactive waste storage systems. Nitrate is known to be an aggressive species for the localized corrosion and SCC of carbon steel while nitrite, hydroxide, and carbonate are inhibitive species. The role of nitrate and nitrite in localized corrosion and cracking appear to be related to their effects on active dissolution and passivity, rather than on corrosion potential. The long-term corrosion potential is influenced mostly by the pH.