Question: Claus Helberg (31 January 1919 – 6 March 2003) was a Norwegian resistance fighter and mountain guide,  was a member of Company Linge, a resistance commando unit that was best known for carrying out, during World War II, which titled series of operations undertaken by Norwegian saboteurs during World War II to prevent the German nuclear weapon project from acquiring heavy water (deuterium oxide), which could have been used by the Germans to produce nuclear weapons?
Context: 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 gliders, and its target was the Vemork "Norsk Hydro" chemical plant in Telemark, Norway which produced heavy water for Nazi Germany.  By 1942, the German nuclear weapons programme had come close to being able to develop a nuclear reactor, but in order for the reactor to function it would require a great deal of heavy water.  The source of the heavy water was the Norsk Hydro plant, which had been occupied in 1940; when the British government learned of the German nuclear developments, it was decided that a raid would be launched to destroy the plant and deny the Germans the heavy water required to develop a nuclear weapon.  Several tactics were discussed and discarded as impractical, and it was finally decided that a small airborne force composed of sappers from the Royal Engineer units attached to 1st Airborne Division would land by glider a short distance from the plant, demolish it with explosives and then escape over the Norwegian border into Sweden. The Girdler sulfide (GS) process, also known as the GeibSpevack (GS) process, is an industrial production method for filtering out of natural water the heavy water (deuterium oxide = DO) which is used in particle research, in Deuterium NMR spectroscopy, deuterated solvents for proton NMR spectroscopy, in heavy water nuclear reactors (as a coolant and moderator) and in deuterated drugs. Heavy water (deuterium oxide, 2H2O , D2O ) is a form of water that contains a larger than normal amount of the hydrogen isotope deuterium (2H or D, also known as "heavy hydrogen"), rather than the common hydrogen-1 isotope (1H or H, also called protium) that makes up most of the hydrogen in normal water.  The presence of deuterium gives the chemical different nuclear properties, and the increase of mass gives it different physical and chemical properties compared to normal "light water". The United States is known to have possessed three types of weapons of mass destruction: nuclear weapons, chemical weapons, and biological weapons.  The U.S. is the only country to have used nuclear weapons in combat, when it detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki during World War II.  It had secretly developed the earliest form of the atomic weapon during the 1940s under the title "Manhattan Project".  The United States pioneered the development of both the nuclear fission and hydrogen bombs (the latter involving nuclear fusion).  It was the world's first and only nuclear power for four years (1945–1949), until the Soviet Union managed to produce its own nuclear weapon.  The United States has the second largest number of deployed nuclear weapons in the world, after Russia. The Heavy Water War (original title Kampen om tungtvannet and alternative title The Saboteurs ) is a six-episode war drama TV miniseries produced by the Norwegian Broadcasting Corporation.  It is a Norwegian/Danish/British co-production, directed by that tells about the German nuclear weapon project and the heavy water sabotage in Norway to disrupt it during the Second World War, with a particular emphasis on the role of Leif Tronstad. The Norwegian heavy water sabotage (Bokmål: "Tungtvannsaksjonen" , Nynorsk: "Tungtvassaksjonen" ) was a series of operations undertaken by Norwegian saboteurs during World War II to prevent the German nuclear weapon project from acquiring heavy water (deuterium oxide), which could have been used by the Germans to produce nuclear weapons.  In 1934, at Vemork, Norway, Norsk Hydro built the first commercial plant capable of producing heavy water as a byproduct of fertilizer production.  It had a capacity of 12 tonnes per year.  During World War II, the Allies decided to remove the heavy water supply and destroy the heavy water plant in order to inhibit the German development of nuclear weapons.  Raids were aimed at the 60 MW Vemork power station at the Rjukan waterfall in Telemark, Norway. Kurt Diebner (13 May 1905 – 13 July 1964) was a German nuclear physicist who is well known for directing and administrating the German nuclear energy project, a secretive program aiming to build nuclear weapons for Nazi Germany during the course of World War II.  Diebner was the administrative director of the German nuclear program after Adolf Hitler, Führer and Reich Chancellor, authorized this program. The German nuclear weapon project (German: "Uranprojekt" ; informally known as the "Uranverein"; English: Uranium Society or Uranium Club ) was a scientific effort led by Germany to develop and produce nuclear weapons during World War II.  The first effort started in April 1939, just months after the discovery of nuclear fission in December 1938, but ended only months later due to the German invasion of Poland, after many notable physicists were drafted into the "Wehrmacht". Claus Helberg (31 January 1919 – 6 March 2003) was a Norwegian resistance fighter and mountain guide.  He was a member of Company Linge, a resistance commando unit that was best known for carrying out Norwegian heavy water sabotage during World War II.  After the war, he worked for the Norwegian Mountain Touring Association until his retirement in 1982.  While volunteering with the Association after his retirement, he helped guide several members of the Scandinavian royalty.  According to the "New York Times", "[he was] the favorite mountain guide of Scandinavian royalty..." These clients included Queen Sonja and Queen Margrethe. The Thamshavn Line sabotage was a series of sabotages against the railway Thamshavn Line in Orkdal, Norway during World War II.  There were four separate sabotages, all performed by Company Linge in an attempt by the Norwegian resistance to prevent Germany from getting the pyrites that were being extracted at the mine at Løkken Verk.
Answer: Norwegian heavy water sabotage