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The Norwegian heavy water sabotage was a series of actions undertaken by Norwegian saboteurs during World War II to prevent the German nuclear energy project from acquiring heavy water (deuterium oxide), which could be used to produce nuclear weapons. In 1934, at Vemork, Norsk Hydro built the first commercial plant capable of producing heavy water as a byproduct of fertilizer production. It had a capacity of 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 Nazi development of nuclear weapons. Raids were aimed at the 60 MW Vemork power station at the Rjukan waterfall in Telemark, Norway. Prior to the German invasion of Norway on 9 April 1940, the ''Deuxième Bureau'' (French military intelligence) removed of heavy water from the plant in Vemork in then-neutral Norway. The plant's managing director, Aubert, agreed to lend the heavy water to France for the duration of the war. The French transported it secretly to Oslo, to Perth, Scotland, and then to France. The plant remained capable of producing heavy water. 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 unsuccessful 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 tugs, a 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 ''Gestapo''. In February 1943, a team of SOE-trained Norwegian commandos succeeded in destroying the production facility with a second attempt, Operation ''Gunnerside''. Operation ''Gunnerside'' was later evaluated by SOE as the most successful act of sabotage in all of World War II. 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 Tinnsjø, preventing the heavy water from being removed. ==Technical background== Enrico Fermi and his colleagues studied the results of bombarding uranium with neutrons in 1934.〔E. Fermi, E. Amaldi, O. D'Agostino, F. Rasetti, and E. Segrè (1934) "Radioacttività provocata da bombardamento di neutroni III," ''La Ricerca Scientifica'', vol. 5, no. 1, pages 452–453.〕 The first person who mentioned the idea of nuclear fission in 1934 was Ida Noddack.〔Ida Noddack (1934) "Über das Element 93," ''Zeitschrift für Angewandte Chemie'', vol. 47, no. 37, pages 653–655.〕〔(another reference )〕 Four years after the Fermi publication, in December 1938, Lise Meitner and Otto Frisch correctly interpreted the radiochemical experimental results of Otto Hahn and 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 tamed, fission could lead to a promising new source of 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. Heavy water and graphite were the prime candidates for moderating the energy of neutrons.〔Weintraub, Bob. (''Lise Meitner (1878–1968): Protactinium, Fission, and Meitnerium.'' ) Retrieved on June 8, 2009.〕 When Nazi Germany investigated the production of an atomic bomb (see German nuclear energy project), a range of options were 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 the option. Although ultimately unsuccessful, the approach chosen has been demonstrated to be technically viable: * Plutonium-239 (239Pu) makes an 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. * Heavy water may be separated from ordinary water by electrolysis. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Norwegian heavy water sabotage」の詳細全文を読む スポンサード リンク
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