Technology Description: Components- The Confined Sluicing End Effector (CSEF) is a remotely operated tool attached to the end of a robotic manipulator arm. Confined sluicing is applicable for dislodging, mobilizing, and removing all waste forms (hard cake, sludge, and bulk supernate) stored in the Hanford Underground Storage Tanks (USTs). The confined sluicing device is attached as an end effector to an articulated arm that enters the tank through an existing access riser. The CSEF is lowered into a tank containing hazardous waste and is used to dislodge, cut, and remove waste material. It is also used to clean and decontaminate the walls of the tank and any residual hardware that remains in the tank. Confined sluicing uses high pressure (10,000 psi or 70 MPa) waterjets to cut the material in the tank into small pieces, and then sucks the material out using a high pressure (around 7,000 psi or 50 MPa) jet pump. Water Jet Cutter The cutting operations take place in a confining shroud, which leads to an aspirating, high pressure jet pump. Water expelled by the jets and all debris excavated by the process are caught and pumped out of the tank before they can flow into the main body of the tank. Therefore, the injected water and fragmented debris are removed without significant water loss to the tank, and the excavations of mixed waste are carried out of the tank as an aqueous slurry. Conveyance of the waste in a slurry pipeline facilitates feed to downstream waste processors and separators. Although waste processing is external to this waste removal system, the slurry water is captured and separated and then recycled back to the waterjet feed tank, forming an approximate closed loop. Some make-up water may be necessary. Recycling the water results in waste minimization because the volume of waste water generated by the sluicing process is minimized. At the end of the entire tank farm remediation program, the waste water would be treated and reclaimed or suitably disposed of. Procedures/Reliability- General Applications and Limitations- Support/Infrastructure Requirements- Program Integration Issues and Compatibility with Other Technologies- Operator Staffing/Skill/Training/Physical Requirements- Acceptability: Environmental and Aesthetic Impacts- Natural Resource Usage- Land Use Impacts- Other Socioeconomic Impacts- No significant environmental impacts are anticipated by the use of this technology. The "closed loop" processing of the waterjet feed water may make this technology more acceptable than other alternatives. Status: Maturity- Preliminary feasibility studies were conducted in FY92. It is anticipated that this system will be fielded in FY97. Much of the equipment and support systems are commercially available now. However, much of the specific design of the waterjet head required for this application must be developed and validated. Future Development- It is projected that CSEF will be able to excavate and remove all types of tank waste, including hard cake, sludge, and bulk supernate. The projected removal rate is 30 gpm with a water-to-solid ratio of 2:1 to 4:1. It is projected that the water expelled by the waterjets and retrieved by the pneumatic conveyor will be "close-looped" and recirculated throughout the entire tank farm reclamation process. This technology is potentially applicable to radioactive or hazardous excavations in remote settings (such as an underground storage tank). The waterjet cutting technology has applications in advanced manufacturing, material research, and in the mining industry. Previous Applications (refs.)- Patents- Patents: None. Industrial Partnerships- University of Missouri-Rolla Competing Technologies: There is presently no baseline technology that can break up and remove all types of tank waste. One possible alternative to confined sluicing is flooding of the tanks with water and continuously pumping the water out; such a method is referred to as general sluicing. General sluicing requires large quantities of water, cannot be used in leaking tanks, and cannot deal with hard, insoluble materials. Effectiveness: Design Specifications. The waterjet operates at 10 kpsi, and the jet pump for the pneumatic conveyor develops a 7 kpsi pressure head. The CSEF system is designed to remove all excavated tank waste at a steady flow of 30 gpm or higher. Confined sluicing will break the waste down into a slurry of small particles that are easily processed. It is anticipated that the water-to-solid ratio will be between 2:1 and 4:1. The system will probably require less than 500 hp, but exact requirements are yet to be defined. Feasibility Study. A feasibility study was conducted in 1992. Feasibility studies have shown that targeted waste removal flow rates of 30 gpm are achievable. It is projected that CSEF will be able to excavate and remove all types of tank waste, including hard cake, sludge, and bulk supernate. The projected removal rate is 30 gpm with a water-to-solid ratio of 2:1 to 4:1. It is projected that the water expelled by the waterjets and retrieved by the pneumatic conveyor will be "close-looped" and recirculated throughout the entire tank farm reclamation process. Cost: Start-up- O&M- The cost of this item has not been estimated because of the ongoing refinement of the technology. Decommissioning- Regulatory Oversight- Rate/Schedule: Safety (worker exposure, safety impacts, etc.): References: 1. DOE-AL, "Technology Information Profile (Rev. 2) for ProTech, Technology Name: High Pressure Waterjet Dislodging and Conveyance End Effector using Confined Sluicing," DOE ProTech Database, TTP Reference Number: AL-232003, March 14, 1993. Contacts: Principal Investigator(s) Dr. David A. Summers TEL (314) 341-4311 FAX Rock Mechanics Facility University of Missouri-Rolla 1006 Kings Highway Rolla, MO 65401 Additional Contacts DOE/OTD Environmental Technology Information Service 1-800-845-2096 DOE Program Manager Sherry Gibson EM-552, Trevion II U.S. Department of Energy Washington, DC 20585 (301) 903-7258 Industrial/University Partnership University of Missouri-Rolla Reporter: Peter C. Wallmann Senior Geologist Golder Associates Inc. 4104 148th Ave NE Redmond, WA 98052 USA TEL 206-883-0777 FAX 206-882-5498 Processed 6/29/94 17:53 Validation: Processed from Technology Catalogue, First Edition, 1994, DOE/EM-0138P, U.S. Department of Energy, Office of Environmental Restoration and Waste Management, Office of Technology Development.
Last Modified: Tuesday, March 25 1997 11:50