To provide the opportunity to exchange knowledge and to provide training in the necessary skills for working underground and for the safe disposal of radioactive waste in general, Nagra established the Grimsel Training Centre (GTC) in 2017, as a permanent platform.

Facing the long-lasting programmes of the radioactive waste management, training the next generation of radioactive waste management scientists was identified by many organisations as one major challenge for the next few years and decades.

To meet the various needs of training and knowledge transfer, the GTC team developed a programme which allows both tailor-made and established courses repeated every two or three years. Also, the combination of more theoretical lectures and hands-on training renders this programme very attractive for various levels of experience and expertise. High quality and relevance of the courses is achieved by involving lecturers from the GTS partner organisations.

Upcoming courses :

GTS Tunnels

From RD&D requirements to in-situ Experiments – how to design and setup URL experiments


This course teaches how to manage and design URL experiments ranging from relatively small experiments with one or two boreholes up to large scale experiments testing and demonstrating the performance of EBS component(s). Each experiment is unique; there is no ‘manual’ that can be referred to.

To this end, new techniques and/or procedures often have to be designed and developed to achieve the experimental goals. Lessons learned from designing and running URL experiments at the GTS will also be presented and discussed.


CFM experiment

Use of radioactive tracers in URL experiments (input to safety cases)

30th August to 1st September 2021 – 3 days - @ GTS

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The GTS is one of only a few URLs where radioactive tracers can be used in tracer migration tests in the geosphere at activities requiring a license. This course aims to show how such in-situ tests can produce results that are more reliable and realistic than standard in-situ tests using non-radioactive tracers. Focus is on showing how results from laboratory based experiments, (the derived parameters of which are used as input to performance assessment calculations), are linked to field scale (1 – 10 m) in-situ tests, as well as improving process understanding of how radionuclides behave both in water conducting fault zones and in the rock matrix.


Engineered Barrier System (EBS) Bentonite properties and applications

6th to 10th September 2021 – 1 week - @ GTS and University of Berne

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This course aims to provide an opportunity to exchange key information and ideas on clay barrier research in order to support engineering designs. Key physiochemical, geochemical and hydromechanical properties as well as relevant analytical techniques and conceptual models will be introduced. The course includes onsite discussion of the large-scale experiments at the GTS studying and demonstrating the performance of bentonite materials.


Grimsel frontpage


Grimsel Test Site (GTS)

The Grimsel Test Site (GTS) located in the Swiss Alps was established in 1984 as a centre for underground Research and Development (R&D) supporting a wide range of research projects on the geological disposal of radioactive waste. International partners from Europe, Asia and North America are working together at this unique facility.

The (GTS) is located at an altitude of 1730 metres in the granitic rock of the Aar Massif in Switzerland. It lies at a depth of around 450 metres beneath the surface and is reached by an access tunnel belonging to the local hydro-power company (Kraftwerke Oberhasli AG, KWO). The GTS tunnel system is around one kilometre long and was excavated in 1983 using a full-face tunnelling machine (diameter 3.5m).