Grimsel Partners from around the world

The Grimsel Test Site was designed as a generic underground rock laboratory and, since the start of its operation in 1984, it has served as a source of knowledge for assessing and developing methods for the characterisation and description of fractured rocks, engineered barrier systems and their interaction with the surrounding rocks and, more generally, for contributing to the assessment of features, events and processes that influence repository performance..

FLG Grimsel, Felslabor AllgemeinThe Grimsel Test Site (GTS) is located at an altitude of 1730 metres within the granitic rock of the Aar Massif in central Switzerland.

The GTS provides an environment which is analogous to that of a repository site so allowing the development and testing of equipment, methodology and models under fully realistic conditions. International partners from Europe, Asia and North America are working together at this unique facility.

Nagra, Felslabor Grimsel, FLG Phase VI, Stollenanlage Untertageforschung, Einlagerungskonzepte entwickeln fuer radioaktive Abfaelle in geologischen Tiefenlagern; Nagra, Felslabor Grimsel, FLG, StollenanlageThe Grimsel test site (GTS) view of interior tunnels

Its all very well to design a waste disposal system - but how do you know that it will work ?

This is where the Grimsel Test Site (GTS) comes in - with experiments to test the long term behaviour of the engineered barriers, to develop and test tools to confirm the suitability of potential geological host rocks and to test the models used to predict its performance as a long-term barrier to radionuclide release.

Many countries have plans for repositories but in order to ensure that their designs will work, they need somewhere to test out their concepts for safe waste disposal.

These tests should be carried out in similar conditions to a repository. The GTS is a research facility several hundred metres underground which provides a relevant environment for equipment, methodology and model tests.

Location of the Grimsel Test Site in Switzerland
View over the Hotel Grimsel Hospiz.

GMT Silo
Febex bentonite backfill


The GTS is a scientific test site and not a potential repository site; although investigations may utilise a wide range of radioactive tracers, no radioactive waste will be disposed of at the GTS.

All experiments utilising a radioactive tracer are supervised by a Radiation Protection Expert (RPE) and follow very strict regulations which were set by HSK (Hauptabteilung für die Sicherheit der Kernanlagen / Swiss Federal Nuclear Safety Inspectorate - now ENSI ) and continues with BAG (Bundesamt für Gesundheit / Swiss Federal Office of Public Health). Click here for details.