Remote Visu al Inspection of Hanford Site Single-Shell Tanks Hanford Site, Washington, USA - 11335

The waste contained in the 149 single-shell tanks is actively being retrieved and stored in 28 double-shell tanks which provide improved leak integrity and better accessibility for inspection. The waste being staged in the double-shell tanks will be removed and sent to the Waste Treatment and Immobilization Plant, for treatment and vitrification. Waste retrieval from the single-shell tanks will continue for several decades requiring single-shell tanks to remain in service long past the initial design life. Due to the extended use of single-shell tanks, a panel of subject matter experts was commissioned to aid the Tank Operating Contractor in better understanding the current structural integrity of the single-shell tanks. One of the recommendations made by the panel was to perform visual inspections of the single-shell tanks to identify signs of degradation in the concrete dome. Remote visual inspection is the currently utilized method of performing qualitative in-service inspections. These inspections supply an overview of the condition of the tank providing valuable information related to concrete degradation (i.e. cracks, spalling, rust stains). Remote inspection equipment is utilized in the nuclear industry for its ability to allow workers to maintain safe distances from radioactive and chemical exposure while still obtaining high quality imagery.