The experimental work focuses on gaining a better understanding on the gas migration phenomenon and coupled THM processes that may lead to the formation of cracks in engineered barrier systems (EBS) under actual repository conditions. Tests mimicking the THM conditions anticipate in EBS are being conducted in the lab under a controlled environment. The effect of interfaces between dissimilar materials will be investigated as well.

The investigate the behavior of an EBS, the MX-80 bentonite powder and pellets are adopted as clay barrier materials, a claystone core is considered for the host rock, and nitrogen is the gas adopted for the migration tests.

In collaboration with the Universitat Politècnica de Catalunya, Spain, a new fully-instrumented multipurpose triaxial cell for EBS has been developed in this project. The cell is the main component of the experimental campaign envisaged in this project to investigate gas flow through EBS interfaces. It is called 'TAMU-UPC Multipurpose Cell'. The other two key components of this research are the 'TAMU Gas Breakthrough Cell' and the advanced unsaturated 'UPC-oedometer'. A GEOTEC triaxial system, and standard oedoemter cells support the experimental investigations. More detail about these devices can be found in the links below:

• UPC Oedometer
• TAMU-UPC Multipurpose Cell
• TAMU Gas Breakthrough Cell
• GEOTAC Triaxial Cell

The experimental campaign involves a variety of material fabrics, injections rates, confinement, liquid saturations and temperatures. Gas flow through the contact between dissimilar materials is being investigated as well.