Reactive transport simulations of uranium migration in the Opalinus Clay depend on ion speciation governed by underlying thermodynamic data

Hennig, Theresa; Kühn, Michael

doi:https://doi.org/10.5194/adgeo-58-11-2022

Articles | Volume 58

https://doi.org/10.5194/adgeo-58-11-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/adgeo-58-11-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 58

20 Oct 2022

| 20 Oct 2022

Reactive transport simulations of uranium migration in the Opalinus Clay depend on ion speciation governed by underlying thermodynamic data

Theresa Hennig and Michael Kühn

Data sets

The PSI/Nagra chemical thermodynamic database 12/07 T. Thoenen, W. Hummel, U. Berner, and E. Curti https://www.psi.ch/en/les/database

Second update on the chemical thermodynamics of uranium, neptunium, plutonium, americium and technecium I. Grenthe, X. Gaona, A. V. Plyasunov, L. Rao, W. Runde, B. Grambow, R. J. M. Konings, A. L. Smith, and E. E. Moore https://www.oecd-nea.org/jcms/pl_20079/chemical-thermodynamics-series

Model code and software

Description of input and examples for PHREEQC Version 3 - A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations D. L. Parkhurst and C. A. J. Appelo https://doi.org/10.3133/tm6A43

Short summary

Safety assessments must demonstrate that radionuclides in potential disposal sites are retained within the containment providing rock zone using reactive transport simulations. Here, this is quantified for the example of uranium in the hydrogeological system of the Opalinus Clay at Mont Terri. Our work clearly shows how sensitive migration lengths resulting from simulations are to the model conceptualisation and selection of underlying data.