KOLLORADO-e3

Figure 1: Images of the overcored LIT experiment: (top) segmented fracture geometry to estimate the extent of the bentonite gel layer in the shear zone (created by Dr. Hinz, Math2Market using volume rendering in GeoDict), (buttom) ocercored Grimsel granodiorite matrix (approx. 6mstarting from the tunnel wall) to the contact zone of the shear Figure 1: Images of the overcored LIT experiment: (top) segmented fracture geometry to estimate the extent of the bentonite gel layer in the shear zone (created by Dr. Hinz, Math2Market using volume rendering in GeoDict), (buttom) ocercored Grimsel granodiorite matrix (approx. 6mstarting from the tunnel wall) to the contact zone of the shear Image: Angewandte Geologie Jena

In-situ experiments in terms of bentonite long-term stability and radio-nuclide mobility at the bentonite – crystalline surface boundary

BMWi grant: 02E11759A

Duration: 01.05.2019 - 31.12.2022

Projectleader: Prof. Thorsten Schäfer

Person in charge: Janis Pingel

Description: 

The overarching goal of the project KOLLORADO-e3 is to further deepen the mechanistic understanding of the processes that, under near-natural, repository-relevant conditions in fractured granite systems, impair the integrity of the bentonite barrier and can lead to colloidal associated radionuclide transport. This includes the basic mechanisms of bentonite erosion and colloid formation at the bentonite backfill / buffer crystalline host rock interface, the radionuclide speciation, in particular the interactions between radionuclides and colloids, and the interactions of colloids with the rock surface, with special consideration of kinetics. The planned work builds on the knowledge gained in the previous Kollorado-e2 project. Kollorado-e3 is closely connected to the Grimsel rock laboratory (GTS, Switzerland) Phase VI project CFM (Colloid Formation and Migration; see https://www.grimsel.com/gts-phase-vi/cfm-section/cfm-introduction), which currently consists of two experiments, (a) the LIT experiment (Long-term In situ Test) and the I-BET experiment (In rock Bentonite Erosion Test).

Experimental investigations include spectroscopic, microscopic and computer-aided methods, both in the laboratory and in the underground rock laboratory in Grimsel (Switzerland) using inter alia accelerator mass spectrometry (AMS) to determine long-term kinetics in these systems. The transferability of the laboratory data to natural systems should then be guaranteed so that they can be incorporated into the long-term security analysis of the GRS (codes: CLAYPOS, CORFRAME and d³f ++). These codes can then be linked to the reactive transport models used by the FSU Jena and KIT-INE in order to ensure an improved understanding of the processes e.g. in the GTS field experiments.

 

Funding:

The KOLLORADO-e3 project is a collaborative project between the FSU Jena, the KIT-INE and the GRS, financed by the BMWi under the project number: 02E1159A. FSU Jena is the coordinator of this joint project.