Nagra’s Grimsel Test Site – open to visitors from June to October

Deep inside the rock of the Grimsel mountain area, over 20 organisations from 12 countries conduct experiments – together with Nagra. Join us on an underground tour. We will gladly show you what is being researched in our rock laboratory.

What is being investigated at the Grimsel Test Site?

Research at the Grimsel Test Site significantly contributes to Switzerland being in a position to construct a safe deep geological repository in the near future. The Test Site provides ideal boundary conditions for a variety of experiments. On a 1:1 scale with a future repository, scientists investigate how well radioactive substances can be retained in drifts and in the rock. Only here at the Grimsel Test Site are scientists from all over the world allowed to use minuscule amounts of radioactive substances to directly investigate the transport of these substances through the rock.

Experiment on the transport of radioactive substances in rock. Photo: © Comet Photoshopping, Dieter Enz

Map of Nagra’s Grimsel Test Site in the Bernese Alps:

Directions to meeting point for guided tours at large car park in Guttannen:

The Grimsel Test Site is located 450 metres beneath the surface of the Juchlistock, at an altitude of 1730 metres above sea-level in the granitic formations of the Aar Massif – and amidst magnificent mountain scenery. The rock laboratory can be reached through the access tunnel of the Oberhasli AG hydropower plant (KWO). The laboratory itself is around one kilometre long.

Your visit to the Grimsel Test Site

  • From June to October, six days a week (Monday to Saturday), we offer guided tours of the Grimsel Test Site for groups ranging from 7 to 25 people. Please note that early registration is important.
  • The tour lasts around two and a half hours and is free of charge.

Registration for a guided tour

Please contact Andrea Wettstein – De Marco to register for a guided tour of the Grimsel Test Site. We look forward to your visit.

Cover photo: Boris Baldinger