The Mont Terri underground lab – edifying on research, regulation, reputation … and shortsightedness

The Mont Terri Project (MTP) is a globally unique underground rock laboratory, run by the Swiss federal administration swisstopo, independent of any implementer or regulator either in the nuclear field or CO₂ storage or geothermal communities (https://www.mont-terri.ch/en). For over three decades, researchers, scientists, engineers and technicians from currently 22 European, American and Asian organisations have participated in international cooperation. More than 170 experiments were performed, three quarters completed and published. Currently, 46(47) experiments are running (https://www.mont-terri.ch/en/experiment-portfolio).

All partners – from B/CAN/F/FRG/JAP/NL/Spain/Switz/UK/USA – are responsible for the research programme, and that with the same rights and obligations. An annual programme is prepared and, on the recommendation of an advisory committee (“Commission de suivi”) – particularly on work safety and risk issues –, must be approved by the owner of the underground, the Canton of Jura.

Apart of the generic aim – to investigate the characteristics of argillaceous formations – novel drilling, measurement and evaluation techniques have been developed in MT, e.g. on pore water content, coupled hydraulic-mechanical simulation or micro-seismic methods. Technologies like container storage, backfilling and sealing of storage tunnels are tested. The MT team not only operates the lab but contributes to conceptualise and execute experiments as well as publish them in scientific journals (e.g., latest: Mosler et al. 2026, Bonitz et al. 2025).

This success might come to an end as – within the so-called “relief program 27” to save 300 million Swiss francs (MCHF) in the federal administration – the Swiss government, in April 2025, mandated its ministry in charge that “swisstopo examine the transfer of responsible operation of the Mont Terri rock laboratory to a third party outside the federal administration” (Federal Council 2025, transl. tf). The Swiss investment of 1.5 MCHF (to be saved according to the government’s idea) very well pays off for Switzerland though, as the research share of the Swiss administration is 14 per cent. The partners, on their side, have invested 120 MCHF so far.

The loss of knowledge and collaboration might have negative repercussions on several levels and in several fields, for instance:

• Research: danger to discontinue experiments on long-term safety or feasibility regarding geological disposal (of nuclear waste) as more than half (25) of the running 47 experiments have the focus on these aspects (MTP 2024, p. 14);
• Knowledge exchange: partners (or other players) may not be as willing as before to share knowledge;
• Reputation: internationally and nationally all actors may lose trust if the federal administration cuts the budget for MT; nuclear waste policy (disposal) or climate policy (Carbon Capture and Storage, CCS, net-zero target) are likely to be negatively affected;
• Acceptance: underground labs considerably contribute to public acceptance in the nuclear waste policy field (Mayer et al. 2023) which should also be investigated in CCS (Federal Council 2022, p. 11).

At any rate, the existing special arrangement of the MPT should be preserved despite any short-sighted austerity measures in the public sector – for scientific, environmental policy and public interest reasons.

References: on slides to be provided