JRP 05-22

Partners

JOGU

PSI

FZD

Contact

Prof. Dr. T. Reich
Johannes Gutenberg-University Mainz - Institute of Nuclear Chemistry Fritz-Strassmann-Weg 2 - 55128 Mainz Germany
Phone +49 (0) 6131 392 52 50
E-mail e-mail

Batch experiments and spectroscopic studies of Np(V) sorption on montmorillonite

Status

 
Terminated - Planned from October 2006 till April 2008

Goals

During this joint research project, the sorption of Np(V) on montmorillonite, in presence/absence of inorganic carbon, will be studied as a function of pH, ionic, strength, and Np concentration. To obtain a molecular-level understanding of the sorption processes, the structure of the dominating surface species will be determined by Np L-edge EXAFS spectroscopy.

In particular, the scientific objectives are:

  • to develop a surface complexation model with surface species, which is consistent with the EXAFS analysis and the macroscopic sorption data;
  • to determine the corresponding binding constants.

Expected results

The results of this joint research project will provide an improved mechanistic understanding of the uptake of Np on montmorillonite (in presence/absence of inorganic carbon), as well as a sorption model for Np for predictive transport modelling.

As clay minerals (such as montmorillonite) are expected to play an important role in regulating the migration of actinides in argillaceous rock systems, this project will contribute to the safety assessment and design of nuclear waste repositories. In addition, montmorillonite is the main component of bentonites, which are cosidered as backfill material for sealing the emplacement tunnels in proposed high-level waste and spent fuel repositories.

Reports