The ability of soil to remove and retain the bulk of the fission product cations from aqueous solution is used as the basis for disposal of large volumes of intermediate level wastes. An experimental system consisting of three 1 million gal disposal pits has been developed at ORNL and through December 1956, received a total of 5.6 million gal of waste containing 58,000 c of Cs137, 15,000 c of Ru106 and lesser amount of Sr89 Sr90, Co60, Sb125 and the rare earths. Sodium ion and nitrate ion account for the largest part of the chemical constituents. The geologic and hydrologic characteristics of the reservation served as a guide in the selection of small areas for detailed study. The information obtained from field studies of a specific area and laboratory investigations of the interaction of waste and typical soil were used to estimate the operating characteristics of a disposal pit. After the pit was in operation, the underground movement of the chemical constituents and radionuclides in the waste was followed by sampling and radiologging observation wells and sampling at stream gauging points in the pit area. These results have confirmed the preoperating estimate of the direction and path of waste movement and the seepage of anion materials such as Ru106 and NO3 through the soil.
©1958Health Physics Society