The Vemork hydroelectric plant, site of the heavy water production
In World War II, Nazi Germany investigated the possibility of building an atomic bomb. As with all bomb design, the main problem was securing enough "weapons grade" material, particular isotopes of either uranium or plutonium. In order to produce these materials, found only in tiny quantities in nature, one must either extract the uranium from natural ore, or "breed" plutonium in a nuclear reactor. The German scientists decided to use plutonium, as the critical mass was smaller, and the bomb itself theoretically much easier to construct.
Unable to perfect a graphite-moderated reactor for plutonium production, they instead explored a heavy water based design. This could have been used to do bomb research, and, ultimately, to breed plutonium from which a bomb could be constructed. At the time, Europe's major supply of heavy water came from the Norwegian Vemork hydroelectric plant, run by Norsk Hydro, near Rjukan in the Telemark region.
Between 1942 and 1944 a sequence of actions by the Norwegian resistance movement and Allied bombers ensured the destruction of the plant and the loss of the produced heavy water. These operations—codenamed Freshman, Grouse and Gunnerside—finally managed to knock the plant out of production in early 1943, basically ending the German research.
Operations Freshman and Grouse
The first attempt to destroy the plant was mounted by the Combined Operations command in November 1942. The plan consisted of two operations, the first would drop a number of Norwegian locals into the area as an advance force, and once in place a party of British engineers would be landed by glider to attack the plant itself.
On 19 October 1942, a four man team of Special Operations Executive (SOE) trained Norwegian partisans were parachuted into Norway. From their drop point in the wilderness they had to ski a long distance to the plant, so considerable time was given to complete this part of the mission, known as Operation Grouse.
On 19 November, Operation Freshman followed with the gliderborne landing onto a frozen lake near the plant. However the thirty-four Royal Engineers of the 1st British Airborne Division, together with the crews of two gliders and one bomber, died when their craft crashed into mountains during poor visibility. The Norwegians were unable to reach the crash site in time, and the survivors were executed by the Germans under Hitler’s Commando Order.
The Norwegian Grouse team thereafter had a long arduous wait in their mountain hideaway, subsisting virtually on moss and lichen during the winter until a reindeer was eventually found and shot just before Christmas.
A 1948 Norwegian movie based on this raid, called Kampen om tungtvannet, features performances by at least two of the original participants in the raid.  (http://www.imdb.com/title/tt0040504/)
British command was aware of the "success" of the Grouse team, and decided to build another operation in concert with them. In February 1943, an additional six Norwegian partisans were dropped into Norway in Operation Gunnerside. By this time the original Grouse team were being referred to as Swallow. They too were successful in landing, and found the Swallow team after a few days of searching. The combined team then made final preparations for their assault on the night of 27 February.
Following the Freshman attempt, mines, floodlights and additional guards were set around the plant. Whilst the mines and lights remained in place, security of the actual plant had slacked somewhat over the winter months. However, the single 75 metre bridge spanning the deep ravine which led to the plant, 200 metres above the River Maan, was well guarded.
The force elected to descend into the ravine, ford the river and climb the far side. All went well. The winter river level was very low and on the far side, where the ground levelled, they followed a single railway track straight into the plant without encountering any guards. The demolition party entered the main basement by a cable tunnel and through a window. Even before Grouse landed in Norway, SOE had a Norwegian agent within the plant who supplied detailed plans and schedule information. Other than keeping the night-watchman quiet, (and finding his glasses for him), no one interfered with their mission or immediate escape following what they described as a "dull thud". A Tommy Gun was purposely left to indicate this was a British raid and not local resistance, to try and prevent reprisals.
All ten made good their escape whereafter six skied 400 kilometres to Sweden while four remained in Norway for further work with the resistance. The plant was restored by April and SOE concluded a repeat raid would be extremely hard as German security was thereafter very considerable. In November the plant was attacked by a massed daylight bombing raid of 143 B-17 bombers dropping 711 bombs; the reason for the original ground assault a year earlier was that the available alternative of night bombing was considered implausible at that time.
While this attack did little damage to the plant, it did stop production for a short period. Almost as soon as production re-started, the USAAF started a series of raids on it. The Germans were convinced that this would eventually result in some "hits", and they decided to abandon the plant and move remaining stocks and critical components to Germany in 1944.
Knut Haukelid discovered their plan and decided to sabotage a ferry carrying the heavy water across Lake Tinnsjø. Eight and half kilos of plastic explosive with two alarm-clock fuses were fixed to the keel of the ferry, Hydro, which was to carry the railway tankers of the water. On 20 February, the ferry and its cargo sank shortly after sailing when in deep water, finally capping the original mission's objective and halting Germany's development programme. A number of Norwegian civilians were killed as the ferry sank.
Unknown to the saboteurs a "Plan B" has been set-up by SOE who arranged a second team to attack the shipment at Herøya should the first attempt fail. The disassembled factory was later found in southern Germany during the closing stages of the war by members of Operation Alsos nuclear seizure force.
With the benefit of hindsight, the consensus opinion on the German wartime nuclear program is that it was a long way from producing a bomb, even without the sabotage. Nevertheless, the feats of the Norwegian saboteurs have made them national heroes.
SOE Norwegian agents involved
- The first agent inside the plant
- Einar Skinnarland
- The Grouse/Swallow Team
- Jens Anton Paulsson
- Arne Kjelstrup
- Knut Haugland
- Claus Helberg
- The Gunnerside Team
- Joachim Rønneberg
- Knut Haukelid *
- Fredrik Kayser
- Kasper Idland
- Hans Storhaug
- Birger Strømsheim
- (Leif Tronstad) (planner, in Britain)
- The Lake Tinnsjø Team
- “Bonzo” alias Knut Haukelid *
- Rolf Sørlie (local resistance)
- Einar Skinnarland (base wireless operator)
- Gunnar Syverstad (plant lab assistant)
- Kjell Nielsen (plant transport manager)
- (“Larsen”) (senior plant engineer)
- (NN) (car procurer and driver)
Books and movies
Some of these exploits were used as the basis for the US 1965 war film “The Heroes of Telemark” starring Kirk Douglas whose character, Dr. Rolf Pedersen, was supposed to be Joachim Rønneberg.
A French/Norwegian black and white docu-film from 1948 titled "La Bataille de l'eau lourde"/"Kampen om tungtvannet" (trans. "The Fight Over the Heavy Water"), featured some of the ‘original cast’, so to speak.
Joachim Rønneberg has stated; "'The Fight over Heavy Water' was an honest attempt to describe history. On the other hand 'Heroes of Telemark' had little to do with reality.”
The book “Skis Against the Atom” (ISBN 0-942323-07-6) is a full first-hand account by Knut Haukelid*, one of the raiders who stayed behind.
The book "Assault In Norway: Sabotaging the Nazi Nuclear Program" by Thomas Gallagher, published by Harcourt Brace Jovanovich, 1975 (ISBN 0151095825) / The Lyons Press, 2002 (ISBN 1585747505) focuses on the part played by the Norwegian commandos.
The book "Operation Freshman: The Rjukan heavy water raid, 1942" by Richard Wiggan, published by W. Kimber, 1986 (ISBN 071830571X) focuses on the ill-fated Operation Freshman.
The book "Blood and Water: Sabotaging Hitler's Bomb" by Dan Kurzman, published by Henry Holt & Company, 1997 (ISBN 0805032061) documents all operations against the Vemork plant.
The book "The Real Heroes of Telemark: The True Story of the Secret Mission to Stop Hitler's Atomic Bomb" by Ray Mears, published by Hodder & Stoughton 2003 (ISBN 0-340-83016-6) describes the events from the perspective of the unique survival skills of the Norweigian commandos. It accompanied a BBC television series.
The book "E=MC2: A Biography of the World's Most Famous Equation" (ISBN 0-330-39165-8) has a rather detailed section on the raid.
The book "Between Silk and Cyanide" by Leo Marks has a chapter about the raid, from the viewpoint of an SOE cryptographer who helped organize the communications between the SOE and the saboteurs.
- http://teachnet.edb.utexas.edu/~lynda_abbott/abtknutslides.html - a slide show from a CNN report about the raids
- http://www.webtek.no/freshman/ - Operation Freshman
- http://www.hydro.com/en/about/history/1929_1945/1943_2.html - Norsk Hydro's official site on Rjukan during the war
- http://www.ronneberg.org/FTfolder/Joachim.html - interview with Joachim Rønneberg