In 1943, six storage tanks were built at the Clinton Laboratories [later to become Oak Ridge National Laboratory (ORNL)] to contain wastes generated by wartime research and development operations. During the following years, these tanks became an integral part of the ORNL waste system and accumulated ∼1.5 × 106 L (400,000 gal) of sludge containing radioactive wastes. Recently, over a period of ∼18 months, these tanks were sluiced, the radioactive sludge resuspended, and the resuspended slurry pumped to the ORNL Hydrofracture Facility for underground disposal.

In this paper, a summary of the development work is given, and the process design and constraints are described. The operating difficulties encountered and overcome included grinder blade erosion, malfunctioning instruments, pump suction plugging, and slurry settling. About 90% of the settled sludge (containing ∼715,000 Ci) was removed from the system.