Deployment of a fluidic pulse jet mixing system for horizontal waste storage tanks at Oak Ridge National Laboratory, Oak Ridge, Tennessee

摘要

A fluidic pulse jet mixing system, designed and fabricated by AEA Technology, was successfully demonstrated for mobilization of remote-handled transuranic (RH-TRU) sludge for retrieval from three 50,000-gal horizontal waste storage tanks (W-21, W-22, and W-23) at Oak Ridge National Laboratory (ORNL). The pulse jet system is unique because it does not contain any moving parts except for some solenoid valves which can be easily replaced if necessary. The pulse jet system consisted of seven modular equipment skids and was installed and commissioned in about 7 weeks. The system used specially designed fluidic jet pumps and charge vessels, along with existing submerged nozzles for mixing the settled sludges with existing supernate in the tank. The operation also used existing piping and progressive cavity pumps for retrieval and transfer of the waste mixtures. The pulse jet system operated well and experienced no major equipment malfunctions. The modular design, use of quick-connect couplings, and low-maintenance aspects of the system minimized radiation exposure during installation and operation of the system. The extent of sludge removal from the tanks was limited by the constraints of using the existing tank nozzles and the physical characteristics of the sludge. Removing greater than 98% of this sludge would require aggressive use of the manual sluicer (and associated water additions), a shielded sluicer system that utilizes supernate from existing inventory, or a more costly and elaborate robotic retrieval system. The results of this operation indicate that the pulse jet system should be considered for mixing and bulk retrieval of sludges in other horizontal waste tanks at ORNL and US Department of Energy sites.