Articles | Volume 56
09 Nov 2021
 | 09 Nov 2021

Uranium migration through the Swiss Opalinus Clay varies on the metre scale in response to differences of the stability constant of the aqueous, ternary uranyl complex Ca2UO2(CO3)3

Theresa Hennig and Michael Kühn

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Cited articles

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Appelo, C. A. J., Van Loon, L. R., and Wersin, P.: Multicomponent diffusion of a suite of tracers (HTO, Cl, Br, I, Na, Sr, Cs) in a single sample of Opalinus Clay, Geochim. Cosmochim. Ac., 74, 1201–1219,, 2010. a, b, c
Bernhard, G., Geipel, G., Reich, T., Brendler, V., Amayri, S., Nitsche, H., and Nitsche, H.: Uranyl (VI) carbonate complex formation: Validation of the Ca2UO2(CO3)3(aq.) species, Radiochim. Acta, 89, 511–518,, 2001. a, b, c, d, e, f, g
Bossart, P. and Thury, M.: Characteristics of the Opalinus Clay at Mont Terri, Reports of the Swiss Geological Survey, 3, 1355-5146, 2008. a
Bradbury, M. H. and Baeyens, B.: Modelling the sorption of Mn(II), Co(II), Ni(II), Zn(II), Cd(II), Eu(III), Am(III), Sn(IV), Th(IV), Np(V) and U(VI) on montmorillonite: Linear free energy relationships and estimates of surface binding constants for some selected heavy metals and actinide, Geochim. Cosmochim. Ac., 69, 875–892,, 2005a. a, b
Short summary
Uranium migration in the Swiss Opalinus Clay is used as an example to quantify the influence of varying values of a stability constant in the underlying thermodynamic database within the law of mass action on the migration lengths. The difference of the stability constant of 1.33 log units lead to changed migration lengths of 5 m to 7 m. With a maximum diffusion distance of 22 m the influence of an uncertain stability constant is negligible for the host rock scale.