EXTENSION OF THE UNDERGROUND RESEARCH FACILITY FOR REAL-SCALE DEMONSTRATION

The research programme for disposal of High-Level radioactive Waste in Belgium (HLW) is reaching the demonstration stage. Designs are finalised for a large-scale demonstration of the current disposal concept. To this extent, the Economic Interest Grouping (EIG) EURIDICE, a joint venture between the Belgian Nuclear Research Centre SCK•CEN and the Belgian Waste Management Agency NIRAS/ONDRAF is managing the extension of the existing HADES underground research facility with a second shaft and connecting gallery to allow for the large-scale nature of the works. SCK•CEN started the construction of the existing facility 20 years ago, aiming at performing in situ research in the Boom Clay, a tertiary clay formation identified as a potential host rock for HLW disposal. The gallery construction in this clay allowed improving the excavation techniques in this type of rock, evolving from a feasibility test to a mechanised technique causing minimal damage to the surrounding host rock. The original freezing technique, adopted based on geotechnical characterisation of deep core samples taken from the surface, has been replaced by an excavation technique without prior ground conditioning. Also, the initially applied cast iron lining has been replaced by the more economical concrete segment lining. During its 20 years lifetime, the existing underground facility has seen many in situ investigations being performed