R1 (nuclear reactor)

Coordinates: 59°21′00″N 18°04′05″E / 59.35000°N 18.06806°E / 59.35000; 18.06806
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The R1 nuclear reactor in the 1960s.

R1 was the first nuclear reactor of Sweden. It was a research reactor located at the KTH Royal Institute of Technology campus at Valhallavägen in central Stockholm, in the rock beneath the current-day Q buildings. The reactor was active from July 13, 1954 to June 6, 1970. The reactor was dismantled, and there is nothing left of it today; the reactor hall however still exists.


As World War II came to a close, the Swedish government in 1950 formed a group of physicists and engineers to study and learn more about the basics – reactor physics, radiation, materials, etc. – but also to produce medical isotopes.[1] The capacity of the reactor was originally 300 kW but was later increased to 1 MW. R1 was housed in a large hall reminiscent of a cathedral giving it the nickname the “Cathedral of Science and Technology”. Rolf Sievert served as the head of the radiation department at KTH Royal Institute of Technology and gave the approval to run the reactor. R1 was soon overtaken by Studsvik for nuclear research and on June 6, 1970 R1 was dismantled.


After being dismantled, the hall that R1 sat was deemed safe and was used for events like art exhibitions, concerts and music videos due to its interesting aesthetic and acoustics.[2] It is open to the public during limited times for tours.[3]

In 2016, the reactor hall was used to film the music video for Alan Walker's song Faded (Restrung). The video was released on 11 February 2016.[4][5]59°21′00″N 18°04′05″E / 59.35000°N 18.06806°E / 59.35000; 18.06806



  1. ^ "Sweden's Reactor 1 – then and now - Nuclear Engineering International". www.neimagazine.com. Retrieved 2021-03-03.
  2. ^ "The Nuclear Reactor You Can Dance In". OZY. 2016-05-29. Retrieved 2021-03-03.
  3. ^ "R1 Nuclear Reactor". Atlas Obscura. Retrieved 2021-03-03.
  4. ^ "Alan Walker - Faded Restrung Video (Behind The Scenes)". Alan Walker / via YouTube. 2016-04-05. Retrieved 2016-05-02.
  5. ^ Walker, Alan (2016-02-11). "Faded (Restrung)". Alan Walker & MER Musikk, Sony Music Entertainment Sweden AB / via YouTube. Archived from the original on 2021-12-14. Retrieved 2016-02-13.