As manager of the HADES underground research laboratory, EIG EURIDICE has accumulated a large technical and scientific expertise over the years, mainly in the following three areas.

1. Excavation and construction technology

Considerable excavation and construction technology expertise was acquired in building the HADES underground research laboratory. Since work began on HADES in the early 1980s, the methods used to excavate and construct galleries in poorly indurated clay have changed significantly. Whereas the first gallery was excavated manually in frozen clay, only industrial techniques were used for the second part of HADES. This demonstrated that it is technically feasible to build galleries at a reasonable speed and at a reasonable cost. The experience gained over the past 30 years in this area will be invaluable when construction gets under way on a real underground repository.

2. Thermo-hydro-mechanical behaviour of poorly indurated clay 

The excavation of galleries and the emplacement of heat-emitting high-level radioactive waste cause changes in the clay host rock in terms of temperature (thermo), behaviour of water in clay (hydro) and mechanical behaviour. The precise behaviour of the clay under the influence of these combined disturbances is crucial to the development of a waste repository in a deep clay formation. The findings of 30 years’ research into the thermo-hydro-mechanical behaviour of the clay have shown that these disturbances will not compromise the safety of the disposal system. One of the key challenges for the next few years will be to confirm and refine this knowledge.

3. Instrumentation and monitoring

A vast array of measuring instruments placed in the underground laboratory and in the surrounding clay, which record what is happening in the clay during excavation and experiments, have enabled us to expand our knowledge in the above two fields. Experience in installing, maintaining and managing these sensors is EURIDICE’s third area of expertise, which will also be important when it comes to monitoring the real waste repository. EURIDICE also uses this expertise to support surface testing of the disposal containers for high-level waste (supercontainer) and to contribute to the preparatory tests for surface disposal of low- and medium-level short-lived waste.