The Evolution of Corrosion Monitoring in Hanford High-level Waste Tanks

Plutonium production and environmental cleanup activities atthe Hanford Site have produced a broad range of contaminatedmaterials and facilities, including 57 million gallons of high-level(i.e., highly-radioactive) nuclear waste stored in 177 undergroundcarbon-steel tanks of either a single-shell or double-shelldesign. Due to age and leakage, all single-shell tanks had beenremoved from service by 1980 and all pumpable liquids had beentransferred from single-shell tanks to sound double-shell tanksby 2004. The double-shell tanks have either exceeded or are expectedto exceed their design life prior to the conclusion of sitecleanup and waste processing activities. Because of the age andimportance of the double-shell tanks to the site’s environmentalcleanup mission, double-shell tank corrosion control and maintenanceactivities are guided by a comprehensive Double Shell TankIntegrity Project. This project implements a variety of controlsand inspections, including corrosion monitoring, to help ensuredouble-shell tank integrity. Though all provisions of the DoubleShell Tank Integrity Project program plan are important to themanagement of the double-shell tanks, this paper focuses on thedevelopment of double-shell tank corrosion monitoring systems.