GTS / Nagra Blog

After two years of virtual ISCO Meetings, we could finally meet in June for a "physical" ISCO Meeting in Brienz-Switzerland.

The two-day meeting was divided into technical sessions (focus: update on ongoing projects and presentation of new project ideas) and an executive session with the FLG partner organisations (focus: organisation and operation of GTS, financial status and planning of the next project phase), complemented by a visit to the Grimsel Test Site.

With more than 30 participants from North America, Asia and Europe it was a very intensive and successful meeting.

By Felix Glauser

Grimsel Space Mission, Manuela Raimbault and Sebasthian Ogalde in their space suits
Source: Comet Photoshopping GmbH, Dieter Enz

Where scientists from around the world can be found conducting research into the disposal of radioactive waste, „astronauts“ in space suits ventured on their first simulated moon walk in mid-July. Now they are back on the Earth’s surface.

„Lots of people spend their holidays at the beach, I spend mine in a cave“, says Sebasthian Ogalde and laughs. Together with five other „astronauts“, he spent nine days in July deep underground in the tunnel system of the Grimsel Test Site. This is where the lunar mission «Asclepios 1» was simulated under the most realistic conditions possible. The 27-year-old satellite engineer from Chile gladly sacrificed his holidays for this opportunity. For seven years he has been doing everything possible to realise his big dream: to become an astronaut! „This simulated lunar mission was a very valuable experience for me. It really felt like we were on a base on the moon“, says Ogalde.

Nagra has been researching the safe disposal of radioactive waste in deep geological repositories for decades. At the Grimsel Test Site, a new long-term, large-scale experiment “HotBENT” (High Temperature Effects on Bentonite Buffers) has been initiated to investigate effects of high temperatures on bentonite-based barriers. The resulting knowledge will help to optimise deep geological repositories.

The focus of the HotBENT large-scale experiment is on bentonite, which is one of several safety barriers of a deep geological repository. Safety barriers enclose the waste in a repository, thus isolating it from the human habitat. Bentonite consists of clay minerals and is used to fill the voids between the disposal canister and the tunnel wall. Many countries will use bentonite in their repositories, which is why it has been well researched. Bentonite has a very low hydraulic permeability and swells upon contact with moisture. This makes it suitable for sealing repository tunnels because it keeps flowing water away from the radioactive waste and helps to retain it in the repository. The name of the experiment already implies that bentonite will be heated. High-level waste generates heat that is released into the emplacement drifts where the waste is emplaced. In the experiment, the heat is simulated with the aid of heaters.

Schematic representation of the test tunnel with its four heaters. Bentonite is used to fill the voids between the disposal canister (or in this case, the heater) and the tunnel wall.

Dr. Ingo Blechschmidt, Head of Grimsel Test Site:

Opening of the Exhibition „Underground Research - World Wide“

As already highlighted by the previous speakers, international cooperation is one of the major factors ensuring the ongoing success of the work at the Grimsel Test Site and at other underground research facilities. Not just by sharing resources but also by sharing expert knowledge while working together allows the development of outstanding projects and experiments which often run for many years.

Moreover, having a number of underground research laboratories operating around the globe helps to develop, test and demonstrate disposal concepts for radioactive waste under a variety of realistic boundary conditions in different geological environments. The contribution of the URLs and the focus of the activities depend on the stage of the national programmes, so each URL programme has its own special characteristics.

Dr. Piet Zuidema, Head of Science & Technology, Nagra:

30 years of the Grimsel Test Site - its contribution to the realisation of deep geological repositories in Switzerland

Dear partners, dear guests, dear colleagues

I would like to welcome you all here to Nagra’s underground research laboratory - the “Grimsel Test Site” (GTS) at around 400 metres below the surface, high up in the Swiss Alps. This small ceremony is dedicated to the celebration of 30 years of research at Grimsel.

I would like to open the celebrations by highlighting the last decades of the successful research performed here and its contribution to our national repository programme and by addressing the very valuable and mutually beneficial role of our international partners, which is exemplified in a new permanent exhibition to be opened today.

Von Andreas Staeger, Berner Zeitung.

Seit dreissig Jahren besteht an der Grimsel ein Felslabor, in dem die Grundlagen für die Lagerung radioaktiver Abfälle erforscht werden. Aus Anlass des Jubiläums ist dort eine Ausstellung eingerichtet worden.

Energiewende hin oder her – das Problem der Entsorgung radioaktiver Abfälle muss gelöst werden. Dieser Aufgabe widmet sich im Auftrag von Bund und Kernkraftwerksbetreibern die nationale Genossenschaft für die Lagerung radioaktiver Abfälle (Nagra). Seit 1984 betreibt sie im Grimselgebiet ein Felslabor. Die Anlage befindet sich nahe der Gerstenegg 400 Meter tief unter dem Juchlistock und liegt damit mitten im harten kristallinen Gestein des Aarmassivs. Sie ist über einen Zugangsstollen der Kraftwerke Oberhasli erschlossen.