Oak Ridge National Laboratory Old Hydrofracture Facility Tank Closure Plan and Grout Development Status Report for FY 1999

U.S. Department of Energy (DOE) facilities across the country have radioactive waste underground storage tanks, which will require either complete removal of the tank contents and tank shells or in-place stabilization of sludge heels. Complete removal of the sludge and tank shells can become costly while providing little benefit to health, safety, and the environment. An alternative to the removal of the residual wastes and tank shells is the use of in situ solidification and stabilization techniques to immobilize the Resource Conservation and Recovery Act (RCRA) and radioactive components present in waste storage tanks. One technology for in situ remediation of tank wastes is Ground Environmental Service's (GES's) Multi-Point-Injection (MPI.) technology. MPI technology is a patented delivery system, which uses simple and inexpensive injection tools for rapid delivery of grout or other treatment agents, as well as for the emplacement of subsurface barriers. Through the use of tailored grout formulations in conjunction with a system of specially designed grout injection tools, MPI technology is capable of producing a uniform mixture of sludge and grout. Grouts can be tailored for the immobilization of specific RCRA and radioactive constituents. The system of injection tools is designed to maximize the mixing efficiency of the grout with the wastes in the tank. MPI technology has been successfully demonstrated on the solidification of shallow buried wastes at the Oak Ridge Y-12 Plant and in large-scale pumping and mixing tests in both cylindrical and horizontal simulated waste tanks. Hot demonstration of the technology will be accomplished during the closure of the Old Hydrofracture Facility (OHF) tank at the Oak Ridge National Laboratory (ORNL) in fiscal year 2000. This report describes the closure plan for the OHF tanks and presents the status of grout formulation development at ORNL