Abstract The heat generated by high-level waste or spent fuel will create disturbances around a deep geological repository (DGR) containing these wastes. Since the 1990s, SCK CEN, EIG EURIDICE and ONDRAF/NIRAS have been characterizing the thermo-hydromechanical (THM) behaviour of Boom Clay and assessing the impact of the thermal disturbances. This research has included laboratory tests as well as in situ experiments in the HADES Underground Research Laboratory. The two types of tests have been complementary. Laboratory tests have allowed understanding of the THM behaviour and determination of associated values of the THM parameters of the clay under well-controlled boundary conditions and loading paths. This knowledge and the parameters were then validated and even improved by in situ tests which allowed investigation of the effects of temperature on the Boom Clay behaviour at large scales. This paper gives an overview of this research and presents the main findings. It also explains how the knowledge gained supports the design of a possible future DGR and contributes to assessing the extent and impact of the THM disturbances in the Boom Clay around a DGR.

Abstract The timeframes involved in nuclear waste management often speak to the imagination, and even transcend it: what does it mean to isolate and contain human-made materials for periods up to hundreds of thousands or even a million years? In this article, we reflect on the role played by the HADES Underground Research Laboratory in making the distant future comprehensible today. Our argument starts by focusing on the pioneering role HADES played and plays in knowledge production on geological disposal. It highlights the heterogeneous nature of scientific experiments and experiences, and the performative role these play in defining matters of concern for research and development. Second, attention is directed to how HADES contributes to the defining of what is considered possible and imaginable, and how it therefore not only renders the future more predictable, but also contributes to the making of that future. We end the paper with a reflection on the implications of what ‘making the future’ could entail from an ethical perspective, discussing how the intergenerational responsibilities that come with these future-making capacities could be handled.