K_d Measurements of Activation, Fission and Heavy Elements in Water/Solid Phase Systems

Abstract

Batch experiments have been carried out to measure K d values, their variations, and some other parameters for radionuclides of interest in safety assessments including long-lived β/γ fission products and α emitters, such as Ra and the light actinides. The parameters investigated were mainly the concentrations of the elements competing with the radionuclides and the pH of the aqueous phases. The systems studied were as close as possible to those that could reasonably be expected to be encountered in a surface/near surface radioactive waste repository. A number of partition mechanisms are discussed.

Modelling of niobium sorption on clay minerals in sodium and calcium perchlorate solutions

“…The results of the sorption experiments in sodium perchlorate solution at alkaline pH are in accordance with those for soil reported by Rhodes [9], and the corresponding results in calcium perchlorate solution are in agreement with those for rock in cement-equilibrated water reported by Kulmala and Hakanen [10]. The results of Legoux et al [30] are by up to two orders of magnitude lower (1.5-2.6 m 3 /kg) than data presented here. The results by X_ONb(OH) 6 −2 .…”

“…Legoux et al [30] are not consistent with their clay content. They measured Nb sorption on quartz rich sediments containing around 10 wt % clay minerals in the pH range from 5.9 to 8.…”

Quantitative antimony speciation in shooting-range soils by EXAFS spectroscopy

“…Under oxic conditions, the pentavalent Sb species SbðOHÞ 6 À should prevail in soil solution at pH > 2.5. This anionic hydrolysis species is adsorbed by Fe oxides at low pH, but should be mobile above their point of zero charge, i.e., at neutral and basic pH values (Crecelius et al, 1975;Legoux et al, 1992;Blay, 2000). Under reducing conditions, the trivalent neutral complex, SbðOHÞ 3 0 , is expected to be the most stable species, which sorbs to Fe oxides over a wide pH range, hence is expected to be rather immobile even in neutral soils (Crecelius et al, 1975;Blay, 2000).…”

Sorption of Nickel and Cobalt on a Size-Fraction of Unconsolidated Glaciofluvial Deposits and on Clay Minerals

“…[2][3][4][5][6] for cobalt. The results were obtained on widely varying solid materials and under very different conditions and do not allow to draw conclusions of general validity even with respect to the shape of the isotherms: nearly linear isotherms are reported in [2,3], whereas isotherms of the Freundlich type are shown in [6] and composite ones in [4,5].…”