Abstract
The Hanford tank reservation in Washington State has 177 double-shelled underground storage tanks that contain approximately 50 million gallons of liquid legacy radioactive waste from cold war weapons production. These tanks will continue to be in operation for at least another twenty years, until further process plans are defined. The objective of the work described in this paper was to obtain a comprehensive understanding of the localized corrosion behavior of carbon steel in waste simulants for three tanks; AY102, AP101, and AY101. While localized corrosion was observed in some of the simulants, the work demonstrated that these simulants are more benign, with respect to localized corrosion, than simulants for Tank AN107 waste, investigated in previous research. Similar to previous findings, nitrite is still the dominant inhibitor than effectively protects the steel from localized corrosion in the simulants. The open circuit potential of the steel in the simulants was dependent on the concentration of oxygen and other oxidizers and could also change as film formation and growth occurs on the tank steel. This finding highlights the importance of monitoring the potential of the tank in the actual waste to better understand the susceptibility of the tank to localized form of corrosion such as pitting and SCC.
