Abstract
A survey of the potential of geological media from the vicinity of the Waste Isolation Pilot Plant site in Southeastern New Mexico for retardation of radionuclide migration in an aqueous carrier was conducted. The survey included the measurement of sorption coefficients (Kd) for twelve radionuclides between three natural water simulants and ten samples from various geological strata. The nuclides included /sup 137/Cs, /sup 85/Sr, /sup 131/I, /sup 99/Tc, /sup 125/Sb, /sup 144/Ce, /sup 152/Eu, /sup 153/Gd, /sup 106/Ru, /sup 243/Am, /sup 244/Cm, and /sup 238/Pu. The compositions of the simulant solutions were those expected of water in contact with potash minerals or halite deposits in the area and in a typical groundwater found in the Delaware Basin. The geological samples were obtained from potential aquifers above and below the proposed repository horizons and from bedded salt deposits in the repository horizons. In brine solutions, Tc and I were not significantly adsorbed by any of the minerals and Cs and Sr showed minimal adsorption (Kd's < 1). The lanthanide and actinide Kd's were typically > 10/sup 3/ and Ru and Sb Kd's varied in the range of 25 to > 10/sup 3/. In the groundwater simulant, Tc and I showed themore » same behavior, but the Kd's of the other nuclides were generally higher. Some initial parametric studies involving pH, trace organic constituents in the simulant solutions, and radionuclide concentrations were carried out. Significant differences in the observed Kd's can result from varying one or more of these solution parameters. « less

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