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Technical Report

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Cerium radioisotopes, cesium radioisotopes, cobalt radioisotopes, dissolved solids, equilibrium, ion exchange, ions, quantitative analysis, radioactive wastes, reservoirs, sedimentation, strontium radioisotopes


The variations of the concentrations of 90Sr and 137Cs at four stations in Dardanelle Reservoir were analyzed as functions of two parameters: concentration of ionic species and the activity released, Ar, from the two 900 Mw reactors which use the reservoir as a source of cooling water. Multiple regression analyses were performed on the radionuclide concentrations using the two parameters as predictors. The analyses indicated that 90Sr is in a state of equilibrium between the solution and the suspended sediment. The position of the equilibrium was found to be quite sensitive to changes in the concentration of alkaline earth cations, M(II). Thus, the concentration of M(II) has a substantial effect on the removal of 90Sr from the water column. The 137CS concentration varied as Ar, indicating that solution-sediment equilibrium has not been attained since the time necessary for newly released 137Cs to come to equilibrium is greater than the mean residence time of water in Dardanelle Reservoir. The occurrence of 144Ce-144Pr in the Reservoir seems to be a consequence of refueling or maintenance of the reactors; the 141Ce as well as 144Ce, it appears, were originally airborne and find their way to the reservoir through runoff.

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