Closure of the Idaho National Laboratory Advanced Test Reactor Complex Catch Tank and Hot Waste Tank Systems - 10240

Legacy tank system components located at the Idaho National Laboratory’s Advanced Test Reactor Complex (formerly Test Reactor Area) are being closed in accordance with the Resource Conservation and Recovery Act under the provisions of the Voluntary Consent Order. The tank system components consist of buried waste tanks, direct-buried piping, and pump/valve vaults. Closure activities consist primarily of removal of the mixed (hazardous and radioactive) debris for disposition. The specific tank subsystems currently undergoing closure include the TRA-630 Catch Tank System and the TRA-004 Hot Waste Storage Tank System. Each of these systems presents significant challenges to successful closure. The Advanced Test Reactor Complex is an operational nuclear reactor testing facility, so protection of co-located laboratory personnel is of paramount importance during closure operations. The radiological contamination contained within these tank systems includes alpha-emitting transuranic isotopes and europium isotopes, which due to their flighty nature, makes contamination control very difficult. There may be issues with the integrity of certain tank system components. Direct-gamma radiation resulting from cobalt and cesium present in the waste necessitates remote operations in many cases. As the components are either direct-buried or located in vaults, access for operations is limited or nonexistent. Due to the presence of significant buildup (as much as 50% in some instances) of solids and sludge in the system piping, a wax fixative (Waxfix™ from Carter Technologies) was selected to lock-down contamination and fix solid waste remaining inside the piping. The wax fixative was selected primarily for its ability to permeate and fix waste residuals. Other products were tested; however, everything else tested floated on top of the waste residual (which, in many cases, occludes the pipe by 50% or more), and did not penetrate and fix the dry, powdery material. The wax had proven during mockup testing to be very effective at complete permeation and penetration of the residuals to mitigate contamination spread. It was determined during integrated mockup testing that to effectively use the wax fixative, free liquid must be removed from the piping system prior to wax introduction. To address the need for remote-handling of waste, a Brokk 330 demolition robot was selected. The Brokk has proven to be an effective tool for sizing and removing tank system components while allowing for separation of workers from direct-radiation exposure. Custom end effectors were developed in conjunction with Brokk AB of Sweden to meet specific project needs. Previous years’ activities included technology development and integrated mockup testing. During 2009, field operations commenced for the TRA-613A vault, the TRA-630 vault, and various direct-buried pipe lines. The project successfully performed internal pipe drying of the TRA-613A vault during spring 2009 by using high-efficiency particulate air filtered vacuums to pull air through various valve lineups, while heating the vault to 60°C. Following completion of drying operations, the vault piping internals were waxed by pumping liquefied wax into low points in the piping network and using high-point, high-efficiency particulate air filtered vents to vent displaced air and monitor wax injection. The Brokk