Norwegian heavy water sabotage

The Norwegian heavy water sabotage were a series of actions taken by Norwegian saboteurs during World War II to prevent the Germans from acquiring heavy water which could be used to produce nuclear weapons.

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 nuclear weapon development, 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. Hans Suess was an advisor to the production of heavy water. Suess had assessed the Rjukan plant as being incapable of producing militarily useful quantities of heavy water for at least five years.

Between 1942 and 1944 a sequence of sabotage actions by the Norwegian resistance movement, as well as Allied bombing, ensured the destruction of the plant and the loss of the heavy water produced. These operations—codenamed "Freshman", "Grouse" and "Gunnerside"—finally managed to knock the plant out of production in early 1943, basically ending the German research.

The raid was later dubbed by the British SOE as the most successful act of sabotage in all of World War II. In hindsight historians today can point out that Hitler was not as close to getting the atomic bomb as then believed, but if the war had continued longer than it did, and the Manhattan project had failed, the raid could have had a significant effect on the course of the war.

Operations Freshman and Grouse

Map showing Rjukan between lakes Møsvatn (West, upstream) and Tinnsjø (East)

Destruction of 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 commandos 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. This plan, unlike those which did not succeed before, included the team studying and memorising blueprints.

Once the Norwegian Grouse team managed to make contact with the British, the British were suspicious, as they had not heard from the team for a long time, many months, as they went off course many times, and were dropped at the wrong place. The British also considered the possibility of Germans contacting them. The secret question took form of: "What did you see in the early morning of (a day)?" The Grouse team replied: "Three pink elephants." The British were ecstatic at the success of the team, and went on with their next phase of operations.

On 19 November 1942, Operation Freshman followed with the gliderborne landing onto the frozen lake Møsvatn near the plant. However the thirty-four Royal Engineers of the 1st British Airborne Division, together with the crews of two Airspeed Horsa gliders and one Handley Page Halifax bomber, died when their aircraft 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. [1]

Operation Gunnerside

British command was aware of the "success" of the Grouse team, and decided to build another operation in concert with them. By this time the original Grouse team were being referred to as Swallow. In February 1943, in Operation Gunnerside, an additional six Norwegian commandos were dropped into Norway by a Halifax bomber of 138 Squadron from RAF Tempsford. 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. (Supplies required by the commandos were dropped with them in special CLE containers. One of these, buried in the snow by a Norwegian patriot to hide it from the Germans, was recovered by him and handed over to an officer of the Army Air Corps, who were exercising in the area in August 1976. The container was brought back to England and is now on display at the Airborne Museum at Aldershot.)

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. The winter river level was very low and on the far side, where the ground leveled, they followed a single railway track straight into the plant without encountering any guards. Even before Grouse landed in Norway, SOE had a Norwegian agent within the plant who supplied detailed plans and schedule information. The demolition party used this information to enter the main basement by a cable tunnel and through a window. 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 British machine gun was purposely left to indicate this was a British raid and not local resistance, to try to 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, of which at least 600 missed the plant, the damage, however, was quite extensive; the reason for the original ground assault a year earlier was that the available alternative of night bombing was considered unrealistic at that time.

Aftermath

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. He recognised a crew member and talked to him, taking this advantage to slip into the bottom of the ship and plant the bomb, after which he escaped. Eight and half kilograms 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 1944, just after midnight, 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. Witnesses reporting seeing barrels floating after the sinking, leading to speculation that they did not really contain heavy water. But an examination of records after the war showed that some barrels were only half full, and therefore would have floated. A few of these may have been salvaged and transported to Germany. Around 2005, an expedition retrieved a barrel (numbered "26") from the bottom of the lake. Its concentration of heavy water matched the records, and confirmed that the shipment was not a decoy.

Unknown to the saboteurs, a “Plan B” had been set-up by the 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

The Gunnerside Team

(Leif Tronstad) (planner, in the United Kingdom)

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

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 saboteurs.
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. 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 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 Norwegian commandos. It accompanied a BBC television documentary series, Real heroes of Telemark which sticks more to the facts than the film it is named after. It also describes the survival aspects of the attack - how to survive for months in a mountain cabin. The name is an obvious pun on above film and its inaccuracy.
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 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.