The NORWEGIAN HEAVY WATER SABOTAGE (Bokmål : Tungtvannsaksjonen,
Nynorsk : Tungtvassaksjonen) was a series of operations undertaken by
Norwegian saboteurs during
World War II
Prior to the German invasion of
The Allies remained concerned that the occupation forces would use the facility to produce more heavy water for their weapons programme. Between 1940 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 Grouse, Freshman, and Gunnerside—finally managed to knock the plant out of production in early 1943.
In Operation Grouse , the British
Special Operations Executive (SOE)
successfully placed four Norwegian nationals as an advance team in the
region of the
Hardanger Plateau above the plant in October 1942. The
Operation Freshman was mounted the following month by
British paratroopers; they were to rendezvous with the Norwegians of
Operation Grouse and proceed to Vemork. This attempt failed when the
military gliders crashed short of their destination, as did one of the
Handley Page Halifax bomber. The other Halifax returned to
base, but all the other participants were killed in the crashes or
captured, interrogated, and executed by the
In February 1943, a team of SOE-trained Norwegian commandos succeeded
in destroying the production facility with a second attempt, OPERATION
These actions were followed by Allied bombing raids. The Germans elected to cease operation and remove the remaining heavy water to Germany. Norwegian resistance forces sank the ferry, SF Hydro , on Lake Tinn , preventing the heavy water from being removed.
* 1 Technical background
* 2 Operations to limit German access to heavy water
* 3 Historical perspective * 4 SOE Norwegian agents involved * 5 Published histories * 6 Fiction, film, and video coverage * 7 References * 8 External links
Enrico Fermi and his colleagues studied the results of bombarding
uranium with neutrons in 1934. The first person who mentioned the
idea of nuclear fission in 1934 was
Ida Noddack . Four years after
the Fermi publication, in December 1938,
Lise Meitner and Otto Frisch
correctly interpreted the radiochemical experimental results of Otto
Fritz Strassmann as evidence of nuclear fission . News of
this discovery spread quickly among physicists and it was realised
that if chain reactions could be controlled, fission might lead to a
new source of great power. What was needed was a substance that could
"moderate" the energy of neutrons emitted in radioactive decay, so
that they could be captured by other fissile nuclei.
APPROACHES TO DEVELOPING A WEAPON
In nuclear weapon development, the main problem is securing sufficient "weapons grade" material. In particular, it is difficult to acquire either fissile isotopes of uranium -235 (235U) or of 239Pu. Weapons grade uranium requires mining, extracting and enriching natural ore. Alternatively, plutonium can be "bred" in reactors fueled by unenriched uranium, which requires chemical separation of the 239Pu produced.
Unlike the Allies, who pursued both the enrichment of uranium and the production of plutonium, German scientists only focused on plutonium production, as this method was less expensive.
Although the most common isotope of uranium, uranium-238 (238U), can be used as secondary fissionable material in hydrogen bombs , it cannot be used as the primary fissile material for an atomic bomb.238U can be used to produce 239Pu, through the fission of 235U which produces neutrons, some of which will be absorbed by 238U creating 239U. After a few days the 239U will decay, turning into weapons-usable 239Pu.
The Germans did not examine ultra-pure graphite because they did not know that the graphite they had tried was too impure to sustain a chain reaction, and abandoned it as a possible moderator. They instead settled on the heavy-water -based reactor design. A heavy water moderated nuclear reactor could be used to do nuclear fission research, and, ultimately, to breed plutonium from which a bomb could be constructed.
HEAVY WATER PRODUCTION
In normal water, there is only one deuterium atom for every 6400
hydrogen atoms, but deuterium is more prevalent in the residue of
water used as an electrolyte . An analysis of the residues from the
Vemork hydroelectric plant , a large-scale hydrogen production plant
using electrolysis of water for ammonia production, showed a
hydrogen/deuterium ratio of 48, most of the deuterium being bound in
The technology is straightforward.
Hans Suess was a German adviser to the production of heavy water. Suess had assessed the Vemork plant as being incapable of producing militarily useful quantities of heavy water in less than five years at its then capacity.
OPERATIONS TO LIMIT GERMAN ACCESS TO HEAVY WATER
French research considered production of 239Pu using both heavy water and graphite moderated reactors. Preliminary French research indicated that the graphite which was then available commercially was not pure enough to serve the purpose, and that heavy water would be required. The German research community had reached a similar conclusion and in January 1940 had procured additional heavy water from Vemork. The German firm IG Farben , which was a partial owner of Norsk Hydro, had ordered 100 kg (220 lb)/month; Norsk Hydro's maximum production rate was then limited to 10 kg (22 lb)/month.
In 1940, the "
Deuxième Bureau " (French military intelligence)
directed three French agents, Captain Muller and Lieutenants Mossé
and Knall-Demars, to remove the world's extant supply, 185 kg (408 lb)
of heavy water from the
Vemork plant in then-neutral Norway. The Norsk
Hydro General Director,
Axel Aubert , agreed to lend the heavy water
to France for the duration of the war, observing that if Germany won
the war, he was likely to be shot. Transportation was difficult as
German Military Intelligence (the
When France was invaded the French nuclear scientist Frédéric
Joliot-Curie took charge of the material, hiding it first in a Banque
de France vault and then in a prison. Joliot-Curie then moved it to
Although the ready inventory of heavy water was removed, the plant remained capable of producing heavy water. In investigations of collaboration launched by Norwegian authorities after the war, Norsk Hydro management's collaboration with the Germans was considered. General Director Aubert's cooperation with the French aided the Norsk Hydro case.
OPERATIONS GROUSE AND FRESHMAN
Destruction of the Vemork plant was mounted by the Combined Operations Headquarters 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 they were in place a party of British engineers would be landed by military glider to attack the plant itself.
On 19 October 1942, a four-man team of
Once the Norwegian Grouse team managed to make contact with the British, the British were suspicious, as they had not heard from the SOE team for a long time: they had been dropped at the wrong place and had gone off course from there several times. The secret question took the 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 Norwegian team's insertion, and the next phase of operations commenced.
On 19 November 1942,
Operation Freshman followed with the planned
glider-borne landing on frozen lake
Møsvatn near the plant. Two
Airspeed Horsa gliders, towed by
Handley Page Halifax bombers, each
glider carrying two pilots and 15
Royal Engineers of the 9th Field
1st British Airborne Division , took off from RAF Skitten
near Wick in
The most important consequence of the unsuccessful raid was that the Germans were now alerted to a determined Allied interest in their heavy water production.
The Norwegian Grouse team thereafter had a long arduous wait in their
mountain hideaway, subsisting on moss and lichen during the winter
until, just before
A reconstruction of the Operation
British authorities were aware the Grouse team was still operational,
and decided to mount another operation in concert with them. By this
time the original Grouse team was being referred to as SWALLOW. On the
night of 16 February 1943, in Operation
Supplies required by the commandos were dropped with them in special CLE containers . (One of these was buried in the snow by a Norwegian patriot to hide it from the Germans; he later recovered it and in August 1976 handed it over to an officer of the British Army Air Corps , which was conducting exercises in the area. The container was brought back to England and was displayed in the Airborne Museum at Aldershot . The museum closed in 2008 and is now part of the Imperial War Museum Duxford ).
Following the failed Freshman attempt, the Germans put mines, floodlights, and additional guards around the plant. While the mines and lights remained in place, security of the actual plant had slackened somewhat over the winter months. However, the single 75 m (246 ft) bridge spanning the deep ravine, 200 m (660 ft) above the river Måna , was fully guarded.
The force elected to descend into the ravine, ford the icy river and
climb the steep hill on the far side. 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 area without encountering
any guards. Even before Grouse landed in
The saboteurs then placed explosive charges on the heavy water electrolysis chambers, and attached a fuse allowing sufficient time for their escape. A Thompson submachine gun was purposely left behind to indicate that this was the work of British forces and not of the local resistance, in order to try to avoid reprisals. A bizarre episode ensued when fuses were about to be lit: the caretaker was worried about his spectacles which were lying somewhere in the room (during the war new glasses were nearly impossible to acquire). A frantic search for the caretaker's spectacles ensued, they were found — and the fuses lit. The explosive charges detonated, destroying the electrolysis chambers.
The raid was considered successful. The entire inventory of heavy
water produced during the German occupation, over 500 kg (1,102 lb),
was destroyed along with equipment critical to operation of the
electrolysis chambers. Although 3,000 German soldiers were dispatched
to search the area for the commandos, all of them escaped; five of
them skied 400 kilometres to
RESUMED OPERATION AND ALLIED AIR RAIDS
Although this attack did no irreparable damage to the plant, it did stop production for several months. The Vemork plant was restored by April and SOE concluded that a repeat commando raid would be extremely difficult, as German security had been considerably improved.
Almost as soon as production restarted, the USAAF started a series of
raids on Vemork. In November, the plant was attacked by a massed
daylight bombing raid of 143 B-17 heavy bombers dropping 711 bombs, of
which at least 600 missed the plant. The damage, however, was quite
Then, on November 16 and 18, 35 B-24 heavy bombers from the 392nd
Bomber Group based in Wendling, Station 118, attacked the
hydro-electric power station at
SINKING THE SF HYDRO
Knut Haukelid , who was the only trained commando in the immediate area, was informed of the German plan to remove the heavy water and advised he would have to muster support and destroy the shipment. He recruited two people. They decided to sabotage a ferry that would be carrying the heavy water across Lake Tinn . One of the people he recruited recognised a ferry crew member and talked to him, taking this advantage to slip into the bottom of the ship and plant the bomb, after which he slipped away. Eight and a half kilograms of plastic explosive with two alarm-clock fuses were fixed to the keel of the ferry, SF Hydro , which was to carry the railway cars with the heavy water drums across Lake Tinn. On 20 February 1944, shortly after setting off around midnight, the ferry and its cargo sank in deep water, finally capping the original mission's objective and halting Germany's atomic bomb development programme. A number of Norwegian civilians were killed as the ferry sank. Witnesses reported seeing steel drums 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.
In 2005, an expedition retrieved a barrel (numbered "26") from the bottom of the lake. Its contents of heavy water matched the concentration noted in the German records, and confirmed that the shipment was not a decoy. However, it also supported the notion that the concentration of heavy water in a number of the barrels was too small to be of value to a weapons program. This might explain the absence of heavy security measures around the shipment, including why the ferry itself was not searched for delayed charges. In the film Heroes of Telemark , the locomotive and train is shown, somewhat implausibly covered with German soldiers. In the Ray Mears BBC coverage, it is stated that in fact the General in command had ordered this specific disposition of troops.
Unknown to the saboteurs, a "Plan B" had been established 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 the Alsos Mission nuclear seizure force.
The Hydroelectric Plant in 2008. The Hydrogen Production Plant building was demolished in 1977.
Recent investigation of production records at
Norsk Hydro and
analysis of an intact barrel that was salvaged in 2004 revealed that
although the barrels in this shipment contained water of pH
14—indicative of the alkaline electrolytic refinement process, they
did not contain high concentrations of D2O. Despite the apparent size
of shipment, the total quantity of pure heavy water was limited, with
most barrels only containing between 1/2–1% pure heavy water,
confirming the success of the Operation
With the benefit of hindsight, the consensus on the German wartime nuclear program is that it was a long way from producing a bomb, even if the Norwegian heavy water had been produced and shipped at the maximum rate. Nevertheless, the unsuccessful British raid (Freshman) and the feats of the Norwegian saboteurs (Swallow, Grouse, Gunnerside) made the top secret war against the heavy water production internationally known and the saboteurs national heroes.
SOE NORWEGIAN AGENTS INVOLVED
The first agent inside the plant
Einar Skinnarland The
Arne Kjelstrup Knut Haugland
Claus Helberg The
As of November 2015, Joachim Rønneberg, age 96, was the last
surviving member of the
A 1962 book by John D. Drummond, titled But For These Men (ISBN 0705700453 ), tells a true account of two dramatic raids: one on the Norsk Hydro heavy water factory at Vemork, and another on the railway ferry "Hydro" to destroy Germany's heavy water production efforts.
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
Jens-Anton Poulsson (Swallow/Grouse) has told the story in the book The Heavy Water Raid: The Race for the Atom Bomb 1942–1944, Orion forlag As (2009), ISBN 978-82-458-0869-8 .
Operation Freshman is covered extensively in two books:
Richard Wiggan's Operation Freshman: The
A 1948 Norwegian film based on Operations Freshman and Grouse, called Kampen om tungtvannet , features performances by at least four of the original participants in the raid.
A 1965 British film based on the Operation
A 1966 book by Czech author František Běhounek , titled Rokle u Rjukanu (Gorge at Rjukan), is a fiction inspired by the events.
On November 8, 2005, the Corporation for Public Broadcasting – WGBH Educational Foundation in Boston, MA aired a program which documented the work of a team of underwater archaeologists exploring the sunken ferry, SF Hydro in Lake Tinn.
A six-episode TV mini-series titled
The Heavy Water War (The
Saboteurs in the UK) tells the story with a particular emphasis on
the role of
* ^ A B C D E Dahl, Per F (1999).
* ^ A B Riste, Olav ; Nøkleby, Berit (1970).
* ^ "NRK ready to declare €8.7 million Heavy Water War". * ^ "Trailer: The Heavy Water War".
* NOVA: Hitler\'s Sunken Secret * A slide show from a CNN