Simulation tools for hazardous waste removal

The primary mission of Oak Ridge National Laboratory (ORNL) during World War 2 was the processing of pure plutonium metal in support of the Manhattan Project. By-products of this process include radioactive cesium-137 and strontium-90. Between 1943 and 1951, the Gunite and Associated Tanks (GAAT) at ORNL were built to collect, neutralize, and storage these by-products. Currently, twelve gunite tanks and four stainless steel tanks are located on the ORNL complex. Characterization studies of these tanks in 1994 indicated that the structural integrity of some of the tanks is questionable. These risks provided the motivation for remediation and relocation of waste stored in the ORNL tanks. A number of factors complicate the remediation process. The material stored in these tanks ranges from liquid to sludge and solid and is composed of organic materials, heavy metals, and radionuclides. Furthermore, the tanks, which range from 12 to 50 ft in diameter, are located below ground and in the middle of the ORNL complex. The only access to these tanks is through one of three access ports that are either 12 or 24 in. in diameter. These characteristics provide a daunting challenge: how can material be safely removed from such a confined structure? This paper describes the existing strategy and hardware projected for use in the remediation process. This is followed by a description of an integrated hardware system model. This investigation has isolated a few key areas where further work may be needed