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The Norwegian heavy water sabotage ( nb, Tungtvannsaksjonen; nn, Tungtvassaksjonen) was a series of Allied-led efforts to halt German heavy water production via hydroelectric plants in Nazi Germany-occupied Norway during World War II, involving both Norwegian commandos and Allied bombing raids. During the war, the Allies sought to inhibit the German development of nuclear weapons with the removal of heavy water and the destruction of heavy-water production plants. The Norwegian heavy water sabotage was aimed at the 60 MW
Vemork Vemork is a hydroelectric power plant outside Rjukan in Tinn, Norway. The plant was built by Norsk Hydro and opened in 1911, its main purpose being to fix nitrogen for the production of fertilizer. At opening, it was the world's largest power pl ...
power station at the
Rjukan Rjukan () is a town and the administrative centre of Tinn municipality in Telemark, Norway. It is situated in Vestfjorddalen, between Møsvatn and Lake Tinn, and got its name after Rjukan Falls west of the town. The Tinn municipality council gr ...
waterfall in Telemark. The hydroelectric power plant at Vemork was built in 1934. It was the world's first site to mass-produce heavy water (as a byproduct of
nitrogen fixing Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but also in industry. Atmo ...
), with a capacity of 12 tonnes per year. Before the
German invasion of Norway German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...
on 9 April 1940, the French
Deuxième Bureau The Deuxième Bureau de l'État-major général ("Second Bureau of the General Staff") was France's external military intelligence agency from 1871 to 1940. It was dissolved together with the Third Republic upon the armistice with Germany. Howeve ...
removed of heavy water from the Vemork plant in then-neutral Norway. The plant's managing director agreed to lend France the heavy water for the duration of the war. The French transported it secretly to
Oslo Oslo ( , , or ; sma, Oslove) is the capital and most populous city of Norway. It constitutes both a county and a municipality. The municipality of Oslo had a population of in 2022, while the city's greater urban area had a population of ...
, then to
Perth, Scotland Perth (Scottish English, locally: ; gd, Peairt ) is a city in central Scotland, on the banks of the River Tay. It is the administrative centre of Perth and Kinross council area and the historic county town of Perthshire. It had a population o ...
, and then to France. The plant was still capable of producing heavy water, however, and the Allies were concerned that the Germans would use the facility to produce more heavy water. Between 1940 and 1944, a series of sabotage actions by the
Norwegian resistance movement The Norwegian resistance ( Norwegian: ''Motstandsbevegelsen'') to the occupation of Norway by Nazi Germany began after Operation Weserübung in 1940 and ended in 1945. It took several forms: *Asserting the legitimacy of the exiled governmen ...
and Allied bombing ensured the destruction of the plant and the loss of its heavy water. These operations — code-named Grouse, Freshman, and Gunnerside — knocked the plant out of production in early 1943. In Operation Grouse, the British
Special Operations Executive The Special Operations Executive (SOE) was a secret British World War II organisation. It was officially formed on 22 July 1940 under Minister of Economic Warfare Hugh Dalton, from the amalgamation of three existing secret organisations. Its p ...
(SOE) successfully placed an advance team of four Norwegians on the Hardanger Plateau above the plant in October 1942. The unsuccessful
Operation Freshman Operation Freshman was the codename given to a British airborne operation conducted in November 1942 during World War II. It was the first British airborne operation conducted using Airspeed Horsa gliders, and its target was the Vemork '' ...
was mounted the following month by British paratroopers, who were to rendezvous with the Operation Grouse Norwegians and proceed to Vemork. This attempt failed when the military gliders (and one of their
tugs A tugboat or tug is a marine vessel that manoeuvres other vessels by pushing or pulling them, with direct contact or a tow line. These boats typically tug ships in circumstances where they cannot or should not move under their own power, suc ...
, a
Handley Page Halifax The Handley Page Halifax is a British Royal Air Force (RAF) four-engined heavy bomber of the Second World War. It was developed by Handley Page to the same specification as the contemporary twin-engine Avro Manchester. The Halifax has its ori ...
) crashed short of their destination. Except for the crew of one Halifax bomber, all the participants were killed in the crashes or captured, interrogated and executed by the
Gestapo The (), abbreviated Gestapo (; ), was the official secret police of Nazi Germany and in German-occupied Europe. The force was created by Hermann Göring in 1933 by combining the various political police agencies of Prussia into one organis ...
. In February 1943, a team of SOE-trained Norwegian commandos destroyed the production facility in Operation Gunnerside; this was followed by Allied bombing raids. The Germans ceased operations, and attempted to move the remaining heavy water to Germany. Norwegian resistance forces then sank the ferry carrying the heavy water, the , on
Lake Tinn A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...
.


Background

Enrico Fermi Enrico Fermi (; 29 September 1901 – 28 November 1954) was an Italian (later naturalized American) physicist and the creator of the world's first nuclear reactor, the Chicago Pile-1. He has been called the "architect of the nuclear age" and t ...
and his colleagues studied the results of bombarding
uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly ...
with neutrons in 1934. That year,
Ida Noddack Ida Noddack (25 February 1896 – 24 September 1978), ''née'' Tacke, was a German chemist and physicist. In 1934 she was the first to mention the idea later named nuclear fission. With her husband - Walter Noddack - and Otto Berg she discove ...
first mentioned the concept of
nuclear fission Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioa ...
. In December 1938, four years after the Fermi publication,
Lise Meitner Elise Meitner ( , ; 7 November 1878 – 27 October 1968) was an Austrian-Swedish physicist who was one of those responsible for the discovery of the element protactinium and nuclear fission. While working at the Kaiser Wilhelm Institute on rad ...
and
Otto Robert Frisch Otto Robert Frisch FRS (1 October 1904 – 22 September 1979) was an Austrian-born British physicist who worked on nuclear physics. With Lise Meitner he advanced the first theoretical explanation of nuclear fission (coining the term) and first ...
correctly interpreted
Otto Hahn Otto Hahn (; 8 March 1879 – 28 July 1968) was a German chemist who was a pioneer in the fields of radioactivity and radiochemistry. He is referred to as the father of nuclear chemistry and father of nuclear fission. Hahn and Lise Meitner ...
and
Fritz Strassmann Friedrich Wilhelm Strassmann (; 22 February 1902 – 22 April 1980) was a German chemist who, with Otto Hahn in December 1938, identified the element barium as a product of the bombardment of uranium with neutrons. Their observation was the k ...
's radiochemical experimental results as evidence of nuclear fission. News of the discovery spread quickly among physicists and it was realized that if chain reactions could be controlled, fission might be a new source of great power. What was needed was a substance which could
moderate Moderate is an ideological category which designates a rejection of radical or extreme views, especially in regard to politics and religion. A moderate is considered someone occupying any mainstream position avoiding extreme views. In American ...
the energy of the secondary neutrons emitted by fission, so they could be captured by other
fissile In nuclear engineering, fissile material is material capable of sustaining a nuclear fission chain reaction. By definition, fissile material can sustain a chain reaction with neutrons of thermal energy. The predominant neutron energy may be typi ...
nuclei. Heavy water and
graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on lar ...
were the prime candidates for moderating neutron energy. When
Nazi Germany Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was ...
investigated the production of an
atomic bomb A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions (thermonuclear bomb), producing a nuclear explosion. Both bomb ...
, a range of options was identified. Although historical records provide limited detail on the German decision to pursue the heavy water approach, it became clear after the war that they had explored that option. Although ultimately unsuccessful, the approach chosen has been demonstrated as technically viable.
Plutonium Plutonium is a radioactive chemical element with the symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits ...
-239 (239Pu) makes effective weapons material, although requiring an implosion-type mechanism as a simpler Thin Man gun-type bomb is not feasible. Heavy water has been demonstrated as an effective moderator for 239Pu production, and may be separated from ordinary water by
electrolysis In chemistry and manufacturing, electrolysis is a technique that uses direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of elements from na ...
. The German program had already been handicapped by the Nazi purging of German
Jew Jews ( he, יְהוּדִים, , ) or Jewish people are an ethnoreligious group and nation originating from the Israelites Israelite origins and kingdom: "The first act in the long drama of Jewish history is the age of the Israelites""The ...
ish
physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate caus ...
s and the
conscription Conscription (also called the draft in the United States) is the state-mandated enlistment of people in a national service, mainly a military service. Conscription dates back to antiquity and it continues in some countries to the present day un ...
of others and ended in the autumn of 1942.


Approaches to developing a weapon

In nuclear-weapon development, the main problem is securing sufficient weapons-grade material; it is particularly difficult to acquire fissile
isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers ( mass numbers ...
s of
uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly ...
-235 (235U) or 239Pu. Weapons-grade uranium requires mining, extracting and enriching natural ore. Plutonium can be "bred" in reactors fueled by unenriched uranium, which requires chemical separation of the 239Pu produced.


Plutonium production

Although the most common
isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers ( mass numbers ...
of uranium,
uranium-238 Uranium-238 (238U or U-238) is the most common isotope of uranium found in nature, with a relative abundance of 99%. Unlike uranium-235, it is non-fissile, which means it cannot sustain a chain reaction in a thermal-neutron reactor. However, it ...
(238U), can be used as secondary
fissile material In nuclear engineering, fissile material is material capable of sustaining a nuclear fission chain reaction. By definition, fissile material can sustain a chain reaction with neutrons of thermal energy. The predominant neutron energy may be typi ...
in hydrogen (fusion) bombs, it cannot be used as the primary fissile material for an atomic (fission-only) 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). The 239U will decay after a few days, turning into weapons-usable 239Pu. The Germans found that a
chain reaction A chain reaction is a sequence of reactions where a reactive product or by-product causes additional reactions to take place. In a chain reaction, positive feedback leads to a self-amplifying chain of events. Chain reactions are one way that sys ...
could not be sustained if
graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on lar ...
was used as a moderator, and abandoned it. Unaware that this was due to impurities, they did not test ultra-pure graphite (which would have been suitable). Instead, they settled on a heavy-water-based reactor design. A heavy-water-moderated nuclear reactor could be used for nuclear-fission research and, ultimately, to breed the plutonium with which a bomb could be made.


Heavy-water production

In normal water, there is only one deuterium atom for every 6,400 hydrogen atoms;
deuterium Deuterium (or hydrogen-2, symbol or deuterium, also known as heavy hydrogen) is one of two stable isotopes of hydrogen (the other being protium, or hydrogen-1). The nucleus of a deuterium atom, called a deuteron, contains one proton and one n ...
is more prevalent in the residue of water used as an
electrolyte An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon dis ...
. An analysis of residues from the Vemork hydroelectric plant, a large-scale nitrate production plant using the
Haber process The Haber process, also called the Haber–Bosch process, is an artificial nitrogen fixation process and is the main industrial procedure for the production of ammonia today. It is named after its inventors, the German chemists Fritz Haber and C ...
, showed a hydrogen-to-deuterium ratio of 48 (most of the deuterium bound in HDO molecules).
Norwegian Institute of Technology The Norwegian Institute of Technology ( Norwegian: ''Norges tekniske høgskole'', NTH) was a science institute in Trondheim, Norway. It was established in 1910, and existed as an independent technical university for 58 years, after which it was ...
lecturer
Leif Tronstad Leif Hans Larsen Tronstad DSO, OBE (27 March 1903 – 11 March 1945) was a Norwegian inorganic chemist, intelligence officer and military organizer. He graduated from the Norwegian Institute of Technology in 1927 and was a prolific researc ...
and
Jomar Brun Jomar Brun MBE (18 June 1904 – 26 August 1993) was a Norwegian chemical engineer. Career Brun graduated from the Norwegian Institute of Technology in 1926, and worked for Norsk Hydro from 1929. He was central in the planning and running of the ...
, head of the hydrogen plant, proposed a project in 1933 (the year heavy water was first isolated). It was accepted by Norsk Hydro, and production began in 1935. The technology is straightforward. Heavy water (D2O) is separated from normal water by electrolysis, because the difference in mass between the two hydrogen isotopes translates into a slight difference in the speed at which the reaction proceeds. To produce pure heavy water by electrolysis requires a large cascade of electrolysis chambers, and consumes large amounts of power. Since excess power was available, heavy water could be purified from the existing electrolyte. Norsk Hydro became the heavy-water supplier for the world's scientific community, as a by-product of fertilizer production for which the ammonia was used.
Hans Suess Hans Eduard Suess (December 16, 1909 – September 20, 1993) was an Austrian born American physical chemist and nuclear physicist. He was a grandson of the Austrian geologist Eduard Suess. Career Suess earned his Ph.D. in chemistry from the U ...
, a German adviser on the production of heavy water, had assessed the Vemork plant as incapable of producing militarily-useful quantities of heavy water in less than five years at its capacity at the time.


Operations to limit German access to heavy water


Pre-invasion efforts

French research considered the production of 239Pu using reactors moderated by heavy water and graphite. Preliminary French research indicated that the graphite then available commercially was not pure enough to serve the purpose, and heavy water would be required. The German research community had reached a similar conclusion, and had procured additional heavy water from Vemork in January 1940. The German firm
IG Farben Interessengemeinschaft Farbenindustrie AG (), commonly known as IG Farben (German for 'IG Dyestuffs'), was a German chemical and pharmaceutical conglomerate. Formed in 1925 from a merger of six chemical companies—BASF, Bayer, Hoechst, Agfa, ...
, a partial owner of Norsk Hydro, had ordered per month; Norsk Hydro's maximum production rate was then limited to per month. The
Deuxième Bureau The Deuxième Bureau de l'État-major général ("Second Bureau of the General Staff") was France's external military intelligence agency from 1871 to 1940. It was dissolved together with the Third Republic upon the armistice with Germany. Howeve ...
(French military intelligence) directed three French agents (Captain Muller and Lieutenants Mossé and Knall-Demars) to remove the world's extant supply, , of heavy water from the Vemork plant in then-neutral Norway in 1940. Norsk Hydro general director
Axel Aubert Axel Aubert (11 December 1873 – 16 December 1943) was a Norwegian chemical engineer who served as Director-General of Norsk Hydro. Biography He was born in Kristiania (now Oslo, Norway). He was the son of Otto Benjamin Andreas Aubert (1841–9 ...
agreed to lend the heavy water to France for the duration of the war, noting that if Germany won the war he would probably be shot. Transportation was difficult, since the
Abwehr The ''Abwehr'' ( German for ''resistance'' or ''defence'', but the word usually means ''counterintelligence'' in a military context; ) was the German military-intelligence service for the ''Reichswehr'' and the '' Wehrmacht'' from 1920 to 1944. ...
(German military intelligence) was present in Norway and had been alerted of ongoing French activities in Norway (although they were not specifically warned about heavy water). If they had become aware of the shipment, they might have tried to intercept it. The French transported it secretly to
Oslo Oslo ( , , or ; sma, Oslove) is the capital and most populous city of Norway. It constitutes both a county and a municipality. The municipality of Oslo had a population of in 2022, while the city's greater urban area had a population of ...
, then to
Perth, Scotland Perth (Scottish English, locally: ; gd, Peairt ) is a city in central Scotland, on the banks of the River Tay. It is the administrative centre of Perth and Kinross council area and the historic county town of Perthshire. It had a population o ...
, and finally to France. When France was invaded, French nuclear scientist
Frédéric Joliot-Curie Jean Frédéric Joliot-Curie (; ; 19 March 1900 – 14 August 1958) was a French physicist and husband of Irène Joliot-Curie, with whom he was jointly awarded the Nobel Prize in Chemistry in 1935 for their discovery of Induced radioactivity. T ...
took charge of the material and hid it in a Banque de France vault and then in a prison. Joliot-Curie moved it to
Bordeaux Bordeaux ( , ; Gascon oc, Bordèu ; eu, Bordele; it, Bordò; es, Burdeos) is a port city on the river Garonne in the Gironde department, Southwestern France. It is the capital of the Nouvelle-Aquitaine region, as well as the prefecture ...
, where it, research papers and most of the scientists (Joliot-Curie remained in France) boarded the British
tramp steamer A boat or ship engaged in the tramp trade is one which does not have a fixed schedule, itinerary nor published Port#Port of call, ports of call, and trades on the spot market as opposed to Freight liner (ship), freight liners. A steamship engaged ...
(one of the many merchant ships involved in saving over 200,000 troops and civilians in the three weeks after the
Dunkirk evacuation The Dunkirk evacuation, codenamed Operation Dynamo and also known as the Miracle of Dunkirk, or just Dunkirk, was the evacuation of more than 338,000 Allied soldiers during the Second World War from the beaches and harbour of Dunkirk, in the n ...
). The ship already had industrial diamonds, machinery and a number of British evacuees aboard. The ''Broompark'' delivered its passengers and cargo, including the global stockpile of heavy water, to
Falmouth, Cornwall Falmouth ( ; kw, Aberfala) is a town, civil parish and port on the River Fal on the south coast of Cornwall, England, United Kingdom. It has a total resident population of 21,797 (2011 census). Etymology The name Falmouth is of English ...
on 21 June. The award of an OBE to Captain Paulsen was recorded in ''
The London Gazette ''The London Gazette'' is one of the official journals of record or government gazettes of the Government of the United Kingdom, and the most important among such official journals in the United Kingdom, in which certain statutory notices ar ...
'' of 4 February 1941. Crucial to the success of the mission was the role played by
Charles Howard, 20th Earl of Suffolk Charles Henry George Howard, 20th Earl of Suffolk, 13th Earl of Berkshire, (2 March 1906 – 12 May 1941) was an English bomb disposal expert who was also an earl in the Peerage of England, belonging to the ancient Howard family. He was styled ...
, the British liaison to the French scientific establishment. Although the supply of heavy water had been removed, the plant was capable of producing more. The Norsk Hydro management's collaboration with the Germans was examined during investigations of
collaborationism Wartime collaboration is cooperation with the enemy against one's country of citizenship in wartime, and in the words of historian Gerhard Hirschfeld, "is as old as war and the occupation of foreign territory". The term ''collaborator'' dates to t ...
begun by Norwegian authorities after the war, but Aubert's cooperation with the French aided the company's case.


Operations Grouse and Freshman

In October 1942,
Combined Operations Headquarters Combined Operations Headquarters was a department of the British War Office set up during Second World War to harass the Germans on the European continent by means of raids carried out by use of combined naval and army forces. History The comm ...
began operations to destroy the Vemork plant. There were two operations; the first ( Operation Grouse) would drop a number of Norwegians in the area as an advance force. When they were in place, a party of British engineers would be landed by
military glider Military gliders (an offshoot of common gliders) have been used by the militaries of various countries for carrying troops (glider infantry) and heavy equipment to a combat zone, mainly during the Second World War. These engineless aircraft were ...
to attack the plant itself (
Operation Freshman Operation Freshman was the codename given to a British airborne operation conducted in November 1942 during World War II. It was the first British airborne operation conducted using Airspeed Horsa gliders, and its target was the Vemork '' ...
). On 18 October 1942, a four-man team of
Special Operations Executive The Special Operations Executive (SOE) was a secret British World War II organisation. It was officially formed on 22 July 1940 under Minister of Economic Warfare Hugh Dalton, from the amalgamation of three existing secret organisations. Its p ...
(SOE)-trained Norwegian commandos parachuted into Norway. Since they had to ski a long distance to the plant from their drop point in the wilderness, considerable time was allotted for Operation Grouse. Unlike previous failed plans, Grouse required the team to memorize blueprints. The British were suspicious, because the Norwegian Grouse team were delayed in contacting SOE team; the Norwegians had been dropped at the wrong place, however, and had gone off course several times. The secret question was, "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 Grouse, and the next phase of the operations began. On 19 November 1942, Operation Freshman followed with a planned glider-borne landing on the frozen lake
Møsvatn Møsvatn (or Møsvann) is the tenth-largest lake in Norway with a surface area of 78.31 km2. It lies primarily Møsstrond, Vinje in Vestfold og Telemark. The lake lies in the watershed of the Skien river (''Skiensvassdrag'') and discharg ...
near the plant. Two
Airspeed Horsa The Airspeed AS.51 Horsa was a British troop-carrying glider used during the Second World War. It was developed and manufactured by Airspeed Limited, alongside various subcontractors; the type was named after Horsa, the legendary 5th-century ...
gliders, towed by
Handley Page Halifax The Handley Page Halifax is a British Royal Air Force (RAF) four-engined heavy bomber of the Second World War. It was developed by Handley Page to the same specification as the contemporary twin-engine Avro Manchester. The Halifax has its ori ...
bombers (each glider carrying two pilots and 15
Royal Engineers The Corps of Royal Engineers, usually called the Royal Engineers (RE), and commonly known as the '' Sappers'', is a corps of the British Army. It provides military engineering and other technical support to the British Armed Forces and is head ...
of the 9th Field Company,
1st British Airborne Division The 1st Airborne Division was an Airborne forces, airborne infantry Division (military), division of the British Army during the Second World War. The division was formed in late 1941 during the World War II, Second World War, after the Prime M ...
), took off from
RAF Skitten Royal Air Force Skitten or more simply RAF Skitten is a former Royal Air Force satellite station directly east of the village of Killimster, located north east of Watten, Caithness, Scotland and northwest of Wick, Caithness, Scotland. On 19 No ...
near
Wick, Caithness Wick ( gd, Inbhir Ùige (IPA: �inivɪɾʲˈuːkʲə, sco, Week) is a town and royal burgh in Caithness, in the far north of Scotland. The town straddles the River Wick and extends along both sides of Wick Bay. "Wick Locality" had a population of ...
,
Scotland Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to th ...
. The towing of gliders, always hazardous, was worse in this case because of the long flight distance to Norway and poor visibility. One of the Halifax tugs crashed into a mountain, killing all seven aboard; its glider cast off but crashed nearby, resulting in several casualties. Although the other Halifax arrived at the vicinity of the landing zone, the zone could not be precisely identified because the link between the
Eureka Eureka (often abbreviated as E!, or Σ!) is an intergovernmental organisation for research and development funding and coordination. Eureka is an open platform for international cooperation in innovation. Organisations and companies applying th ...
(ground) and Rebecca (aircraft) radar beacons failed. After many tries and with fuel running low, the Halifax pilot decided to abort the operation and return to base. Shortly afterward, the tug and glider experienced heavy turbulence and the tow rope broke. The glider crash-landed near the crash site of the other glider, killing and injuring several more people. The Norwegians were unable to reach the crash sites in time; the survivors were captured by the
Gestapo The (), abbreviated Gestapo (; ), was the official secret police of Nazi Germany and in German-occupied Europe. The force was created by Hermann Göring in 1933 by combining the various political police agencies of Prussia into one organis ...
, who tortured and later had them executed under
Adolf Hitler Adolf Hitler (; 20 April 188930 April 1945) was an Austrian-born German politician who was dictator of Germany from 1933 until his death in 1945. He rose to power as the leader of the Nazi Party, becoming the chancellor in 1933 and then ...
's
Commando Order The Commando Order () was issued by the OKW, the high command of the German armed forces, on 18 October 1942. This order stated that all Allied commandos captured in Europe and Africa should be summarily executed without trial, even if in pr ...
. The unsuccessful raid alerted the Germans to Allied interest in their heavy-water production. The surviving Norwegian Grouse team had a long wait in their mountain hideaway, subsisting on
moss Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) ''sensu stricto''. Bryophyta (''sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and hornw ...
and
lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.reindeer just before Christmas.


Operation Gunnerside

British authorities, aware that the Grouse team was still operational, decided to mount another operation with them; by this time, the Grouse team was known as Swallow. On the night of 16 February 1943, in Operation Gunnerside (named after the village of
Gunnerside Gunnerside is a village in the Richmondshire district of North Yorkshire, England. It is situated on the B6270 road, east of Muker and west of Grinton. The village lies between the River Swale and its tributary, Gunnerside Beck, in the Swal ...
, where SOE head
Charles Jocelyn Hambro Air Commodore Sir Charles Jocelyn Hambro, (3 October 189728 August 1963) was a British merchant banker and intelligence officer. Life Hambro was born into a banking family of Danish Jewish origin which had settled in Dorset and the City of Lo ...
and his family used to shoot grouse), an additional six Norwegian commandos were dropped by parachute by a 138 Squadron
Halifax bomber The Handley Page Halifax is a British Royal Air Force (RAF) four-engined heavy bomber of the Second World War. It was developed by Handley Page to the same specification as the contemporary twin-engine Avro Manchester. The Halifax has its ori ...
from
RAF Tempsford RAF Tempsford is a former Royal Air Force station located north east of Sandy, Bedfordshire, England and south of St. Neots, Cambridgeshire, England. As part of the Royal Air Force Special Duty Service, the airfield was perhaps the most ...
. They landed successfully, and found the Swallow team after a few days of searching on cross-country skis. The combined team made final preparations for their assault, scheduled for the night of 27–28 February 1943. Supplies required by the commandos were dropped with them in special CLE containers. One container was buried in the snow by a Norwegian patriot to hide it from the Germans; he later recovered it, and gave it to an officer of the British Army Air Corps (which was conducting exercises in the area) in August 1976. The container was brought back to England and displayed at the Airborne Museum at Aldershot, which became part of the
Imperial War Museum Duxford Imperial War Museum Duxford is a branch of the Imperial War Museum near Duxford in Cambridgeshire, England. Britain's largest aviation museum, Duxford houses the museum's large exhibits, including nearly 200 aircraft, military vehicles, artill ...
. After the failed Freshman attempt, the Germans placed mines, floodlights, and additional guards surrounding the plant. Although the mines and lights remained in place, security at the plant had weakened over the winter. The bridge spanning the deep ravine above the river
Måna The Måna or Måne is a river in Tinn in Vestfold og Telemark, Norway; it flows from Møsvatn through Vestfjorddalen and Rjukan to Vestfjorden in Lake Tinn. It is part of the Skiensvassdraget drainage basin. The river has several power statio ...
, however, was fully guarded. The force decided 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 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 in the plant who supplied detailed plans and schedules. The demolition party used this information to enter the main basement by a cable tunnel and through a window. The only person they encountered in the plant was a Norwegian caretaker named Johansen, who was very willing to cooperate with them. The saboteurs then placed explosive charges on the heavy-water electrolysis chambers, and attached a fuse which allowed sufficient time for their escape. In an attempt to prevent reprisals, a
Thompson submachine gun The Thompson submachine gun (also known as the "Tommy Gun", "Chicago Typewriter", "Chicago Piano", “Trench Sweeper” or "Trench Broom") is a blowback-operated, air-cooled, magazine-fed selective-fire submachine gun, invented by United Sta ...
was purposely left behind to indicate that this was the work of British forces and not the local resistance. When the fuses were about to be lit, the caretaker was worried about his spectacles (which were somewhere in the room; during the war, new eyeglasses were nearly impossible to obtain). A frantic search ensued; the spectacles 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 , was destroyed with equipment critical to the operation of the electrolysis chambers. Although 3,000 German soldiers were dispatched to search the area for the commandos, all escaped; five commandos escaped by
skiing Skiing is the use of skis to glide on snow. Variations of purpose include basic transport, a recreational activity, or a competitive winter sport. Many types of competitive skiing events are recognized by the International Olympic Committee (IO ...
to Sweden, two proceeded to Oslo (where they assisted
Milorg Milorg (abbreviation of militær organisasjon – military organization) was the main Norwegian resistance movement during World War II. Resistance work included intelligence gathering, sabotage, supply-missions, raids, espionage, transport of ...
), and four remained in the region for further resistance work.


Resumed operation and Allied air raids

The attack halted production for several months, although it did not permanently damage the Vemork plant. The plant was repaired by April; SOE concluded that a repeat commando raid would be extremely difficult, since German security was considerably improved. Almost as soon as production resumed, the
USAAF The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...
began a series of raids on Vemork. The plant was attacked in November by a massive daylight bombing raid of 143
B-17 The Boeing B-17 Flying Fortress is a four-engined heavy bomber developed in the 1930s for the United States Army Air Corps (USAAC). Relatively fast and high-flying for a bomber of its era, the B-17 was used primarily in the European Theater ...
heavy bomber Heavy bombers are bomber aircraft capable of delivering the largest payload of air-to-ground weaponry (usually bombs) and longest range (takeoff to landing) of their era. Archetypal heavy bombers have therefore usually been among the larges ...
s, which dropped 711 bombs. Although the raid caused extensive damage, at least 600 bombs missed the plant. On 16 and 18 November, 35
B-24 The Consolidated B-24 Liberator is an American heavy bomber, designed by Consolidated Aircraft of San Diego, California. It was known within the company as the Model 32, and some initial production aircraft were laid down as export models de ...
heavy bombers from the 392nd Bomber Group (based at Wendling, Station 118) extensively attacked the hydro-electric power station at
Rjukan Rjukan () is a town and the administrative centre of Tinn municipality in Telemark, Norway. It is situated in Vestfjorddalen, between Møsvatn and Lake Tinn, and got its name after Rjukan Falls west of the town. The Tinn municipality council gr ...
. The missions, the bomber group's longest, lasted and hours respectively. There was less need for ground assaults than a year earlier, since night bombing (previously unrealistic due to German air cover) was now an alternative. The Germans, convinced that air raids would result in further serious damage, decided to abandon the plant and move its remaining stocks and critical components to Germany in 1944.


Sinking of the SF ''Hydro''

Knut Haukelid Knut Haukelid ( May 17, 1911 - March 8, 1994) was a Norwegian military officer. He was a Norwegian resistance movement soldier during World War II, most notable for participating in the Norwegian heavy water sabotage. Early life Knut Anders Ha ...
(the only trained commando in the immediate area) was informed of the German plan to remove the heavy water, and was advised to muster support and destroy the shipment. Haukelid recruited two people, and they decided to sabotage a ferry which would be carrying the heavy water across
Lake Tinn A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...
on the
Tinnsjø railway ferry Tinnsjø railway ferry was a Norwegian railway ferry service on Lake Tinn that connected the Rjukan Line and Tinnoset Line. The long ferry trip made it possible for Norsk Hydro to transport its fertilizer from the plant at Rjukan to the port ...
. One of his recruits recognized a ferry-crew member and spoke with him, taking an opportunity to slip into the bottom of the ship, plant the bomb and slip away. Eight-and-a-half kilograms of
plastic explosive Plastic explosive is a soft and hand-moldable solid form of explosive material. Within the field of explosives engineering, plastic explosives are also known as putty explosives or blastics. Plastic explosives are especially suited for explos ...
s (with two alarm-clock fuses) were fixed to the keel of the , which would transport railway cars with drums of the heavy water across Lake Tinn. The ferry and its cargo sank in deep water shortly after its departure around midnight on 20 February 1944. Witnesses reported seeing steel drums floating after the ferry sank, leading to speculation that they did not really contain heavy water; an examination of records after the war showed that some barrels were only half-full, however, and would have floated. A few may have been salvaged and transported to Germany. Despite the mission's intention to minimize casualties, 18 people were killed; 29 survived. The dead were 14 Norwegian crew and passengers and four German soldiers. A 2005 expedition retrieved a barrel, numbered "26", from the bottom of the lake. Its heavy-water contents matched the concentration noted in German records, confirming that the shipment was not a decoy. The concentration of heavy water in a number of the barrels was too small to be of value to a weapons program, however, which might explain the lack of tight security around the shipment and why the ferry was not searched for bombs. In the film ''
The Heroes of Telemark ''The Heroes of Telemark'' is a 1965 British war film directed by Anthony Mann based on the true story of the Norwegian heavy water sabotage during the Second World War from ''Skis Against the Atom'', the memoirs of Norwegian resistance soldier ...
'', the locomotive and train is shown covered with German soldiers, according to
Ray Mears Raymond Paul Mears (born 7 February 1964) is a British woodsman, instructor, businessman, author and TV presenter. His TV appearances cover bushcraft and survival techniques. He is best known for the TV series '' Ray Mears' Bushcraft'', '' Ra ...
'
BBC Television BBC Television is a service of the BBC. The corporation has operated a Public service broadcasting in the United Kingdom, public broadcast television service in the United Kingdom, under the terms of a royal charter, since 1927. It produced t ...
coverage, the general in command had ordered this disposition of troops.BBC TV documentary about the raid based on the survival skills, who actually interviewed the saboteur


Historical perspective

Recent investigation of production records at Norsk Hydro and analysis of an intact barrel which was salvaged in 2004 indicated that although the barrels in this shipment contained pH 14 water (suggestive of the alkaline electrolytic-refinement process), they did not contain high concentrations of D2O. Despite the apparent shipment size, the total quantity of pure heavy water was limited; most barrels contained only 0.5–1.0 percent heavy water, confirming the success of Operation Gunnerside in destroying higher-purity heavy water. The Germans would have needed a total of about of heavy water to operate a nuclear reactor, and the manifest indicated that there was only of heavy water being transported to Germany. The ''Hydro'' was carrying too little heavy water to supply one reactor, let alone the 10 or more tons of heavy water needed to make enough plutonium for a nuclear weapon. The historical consensus about the
German nuclear weapons program The Uranverein ( en, "Uranium Club") or Uranprojekt ( en, "Uranium Project") was the name given to the project in Germany to research nuclear technology, including nuclear weapons and nuclear reactors, during World War II. It went through se ...
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. However, the unsuccessful
Operation Freshman Operation Freshman was the codename given to a British airborne operation conducted in November 1942 during World War II. It was the first British airborne operation conducted using Airspeed Horsa gliders, and its target was the Vemork '' ...
and the efforts of the saboteurs in Swallow, Grouse and Gunnerside made the secret war on heavy-water production internationally known.


Agents

Joachim Rønneberg, the last surviving member of the Gunnerside team, died on 21 October 2018 at age 99. ''
The New York Times ''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid ...
'' reported that at 95, Rønneberg was "still mentally sharp ... and possessed of the unflappable calm that so impressed British military commanders more than 70 years ago." Einar Skinnarland was the first agent inside.


Histories

After interviewing Nielsen and Helberg, Barbara Wace of the Associated Press filed a news article on the sabotage in May 1945. Wartime censorship delayed publication until after the
atomic bombings of Hiroshima and Nagasaki The United States detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August 1945, respectively. The two bombings killed between 129,000 and 226,000 people, most of whom were civilians, and remain the onl ...
in August 1945. '' But For These Men'' (), a 1962 book by John D. Drummond, recounts two dramatic raids: on the Norsk Hydro heavy-water factory at Vemork and another the railway ferry ''Hydro''. ''The Real Heroes of Telemark: The True Story of the Secret Mission to Stop Hitler's Atomic Bomb'', a 2003 book by
Ray Mears Raymond Paul Mears (born 7 February 1964) is a British woodsman, instructor, businessman, author and TV presenter. His TV appearances cover bushcraft and survival techniques. He is best known for the TV series '' Ray Mears' Bushcraft'', '' Ra ...
(), emphasises the Norwegian commandos' unique survival skills. The book is a companion volume to '' The Real Heroes of Telemark'', a
BBC #REDIRECT BBC Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
television documentary series. ''Skis Against the Atom'' () is a first-hand account by
Knut Haukelid Knut Haukelid ( May 17, 1911 - March 8, 1994) was a Norwegian military officer. He was a Norwegian resistance movement soldier during World War II, most notable for participating in the Norwegian heavy water sabotage. Early life Knut Anders Ha ...
, one of the Gunnerside raiders who remained behind. Jens-Anton Poulsson (Swallow and Grouse) wrote ''The Heavy Water Raid: The Race for the Atom Bomb 1942–1944'' (), a 2009 book. Operation Freshman is covered in two books: Richard Wiggan's 1986 ''Operation Freshman: The Rjukan Heavy Water Raid 1942'' () and Jostein Berglyd's 2007 ''Operation Freshman: The Actions and the Aftermath'' ().
Richard Rhodes Richard Lee Rhodes (born July 4, 1937) is an American historian, journalist, and author of both fiction and non-fiction, including the Pulitzer Prize-winning ''The Making of the Atomic Bomb'' (1986), and most recently, ''Energy: A Human History ...
's
Pulitzer Prize The Pulitzer Prize () is an award for achievements in newspaper, magazine, online journalism, literature, and musical composition within the United States. It was established in 1917 by provisions in the will of Joseph Pulitzer, who had ma ...
-winning book, ''
The Making of the Atomic Bomb ''The Making of the Atomic Bomb'' is a contemporary history book written by the American journalist and historian Richard Rhodes, first published by Simon & Schuster in 1987. It won the Pulitzer Prize for General Non-Fiction, the National Book ...
'', includes details of the events.
Leo Marks Leopold Samuel Marks, (24 September 1920 – 15 January 2001) was an English writer, screenwriter, and cryptographer. During the Second World War he headed the codes office supporting resistance agents in occupied Europe for the secret Special ...
' 1998 book, '' Between Silk and Cyanide: A Codemaker's Story 1941–1945'' (), also details the story. Marks (SOE's cryptographer) knew the Norwegian team, trained them in
cryptography Cryptography, or cryptology (from grc, , translit=kryptós "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adve ...
so they could communicate with SOE in England, and followed their progress after they were dropped in Norway. The raid is the subject of ''Assault in Norway: Sabotaging the Nazi Nuclear Program'' (), a 2002 book by Thomas Gallagher based on interviews with many of the commandos. An account of Operation Gunnerside is part of Neal Bascomb's 2016 ''The Winter Fortress: The Epic Mission to Sabotage Hitler's Atomic Bomb'' (). Damien Lewis's book ''Hunting Hitler's Nukes: The Secret Race to Stop the Nazi Bomb'' (), also published that year, details the raid and the sinking of the SF ''Hydro''. The 2018 book, ''Heroes of Telemark; Sabotaging Hitler's atomic bomb, Norway 1942–44'' by David Greentree (), describes the operation's planning, execution and aftermath.


In popular culture

'' Operation Swallow: The Battle for Heavy Water'' (''Kampen om tungtvannet''), a 1948 Norwegian film based on Operations Freshman and Grouse, includes several participants in the raid. ''
The Heroes of Telemark ''The Heroes of Telemark'' is a 1965 British war film directed by Anthony Mann based on the true story of the Norwegian heavy water sabotage during the Second World War from ''Skis Against the Atom'', the memoirs of Norwegian resistance soldier ...
'', a 1965 British film based on Operation Gunnerside, features one of the original participants in the raid as the Nazi pursuer of the escapees. On 8 November 2005, the
Corporation for Public Broadcasting The Corporation for Public Broadcasting (CPB) is an American publicly funded non-profit corporation, created in 1967 to promote and help support public broadcasting. The corporation's mission is to ensure universal access to non-commercial, ...
's
WGBH-TV WGBH-TV (channel 2), branded on-air as GBH or GBH 2 since 2020, is the primary PBS member television station in Boston, Massachusetts, United States. It is the flagship property of the WGBH Educational Foundation, which also owns Boston's se ...
in
Boston Boston (), officially the City of Boston, is the state capital and most populous city of the Commonwealth of Massachusetts, as well as the cultural and financial center of the New England region of the United States. It is the 24th- most p ...
aired a documentary about the work of underwater archaeologists exploring the sunken SF ''Hydro'' in Lake Tinn. BBC News interviewed Joachim Rønneberg, the leader and last surviving member of the Gunnerside team, in 2013 for the 70th anniversary of Operation Gunnerside. '' The Heavy Water War'' (''The Saboteurs'' in the UK), a six-episode TV mini-series, emphasises the role of
Leif Tronstad Leif Hans Larsen Tronstad DSO, OBE (27 March 1903 – 11 March 1945) was a Norwegian inorganic chemist, intelligence officer and military organizer. He graduated from the Norwegian Institute of Technology in 1927 and was a prolific researc ...
. The Norwegian–Danish–British co-production was initially broadcast on 4 January 2015. ''
Battlefield 5 ''Battlefield V'' is a first-person shooter game developed by DICE and published by Electronic Arts. It is the eleventh main installment in the ''Battlefield'' series and the successor to 2016's '' Battlefield 1'', and was released for Microsoft ...
'' In 2019 the popular video game franchise battlefield featured the commando raids of the plant and the ferry bombing in "Battlefield V". However it features no British or Norwegian team of commandos. Instead a young Norwegian girl named Solveig (player character) operates a solo mission into the facility to rescue her mother who is now hostage and was a scientist working at the plant. Upon the player reaching this objective the mother informs the player they must destroy the plant due to its heavy water production and deliver intel at a rendezvous point. After completing this, Solveig suffering from hypothermia falls into subzero water, climbs out, falls asleep, wakes up and eventually makes it to a cabin with a lone german she quickly overpowers physically before finally warming up and reading the intel. After doing so the next day she decides to strike the ferry carrying the heavy water alone. These events vary greatly from the historical operations. Fans of the Battlefield franchise have been critical of this and other historical inaccuracies present in the game.


Footnotes


External links


Norsk Hydro's official site on Rjukan during the war





Annotated bibliography for Norwegian heavy water sabotage
from the
Alsos Digital Library for Nuclear Issues The Alsos Digital Library for Nuclear Issues is a searchable collection of vetted annotations and bibliographic information for resources including books, articles, films, CD-ROMs, and websites pertaining to nuclear topics. Part of the United States ...
{{DEFAULTSORT:Heavy water sabotage, Norwegian Battles and operations of World War II involving Norway Military history of Norway during World War II Norwegian resistance movement Nuclear program of Nazi Germany World War II sabotage