EVIDENT

Erosion of bentonite under in-situ conditions by the action of natural waters in deep geological repositories

BMWi grant 02 E 12153A

Duration: 01.06.2023 till 30.05.2026

Project leader: Prof. Thorsten Schäfer

Personnel in charge: Léon Frederic Van Overloop

Kooperation: KITExternal link, GRSExternal link, GTS/CFMExternal link                                                            

Description: 

The overall objective of the project is to increase the mechanistic understanding of the processes critical for the integrity of the geotechnical barrier under near-natural, repository-relevant conditions in fractured granite systems and to provide robust predictive modeling of the bentonite buffer and colloid-borne radionuclide transport.

Work package 1 (WP 1) focuses on the investigation of the erosion behavior of bentonite after a heat pulse and the evaluation of the integrity of the bentonite barrier by comparing laboratory and field experiments.

In work package 2 (WP 2), the focus is on robust predictive modeling of the bentonite buffer and colloid-borne radionuclide transport. This includes new approaches to charge regulation of the surfaces to describe colloid stability, the further development of the COFRAME calculation program for colloid-borne radionuclide transport and the consideration of uncertainties in the input parameters in a probabilistic uncertainty analysis. In addition, the further qualification of the codes CLAYPOS and COFRAME for the description of radionuclide transport (diffusion and advective transport through fractured media) is aimed at.

The collaboration of both work packages contributes to the development of a comprehensive understanding of geotechnical barriers and radionuclide transport in fractured granite systems to ensure the safety of repositories.