World War II: Nuclear Weapons

Figure 1.--.

Nuclear psyicists in several countries began working on atomic energy before the War. Quite a number were Jews to the extent that German Führer Adolf Hiltler called nuclear physics "Jewish phsycics". The Germans were the leaders in this work and among their most important researchers was a female Jewish pysicist whose colleages helped her escape the Reich. After the outbreak of World War II, the focus shifted to weapons research. While Germany led the world in neuclear physics, only the United States had the industrial capacity to actually launch a nuclear weapons project. The German lead caused many of the Jewish scientists to support the Anglo-American effort. The effiort became known as the Manhattan Project which was the largest weapons development program in history. It was initiated by President Roosevelt when work done by German physicists led to concern that the NAZIs might build an atomic bomb. The Germans were limited by the massive industrial requirements of the industry. And Hitler viewed nuclear physics as Jewsish science. The United States did not have the same industrial constraints the Germans faced. The project required about 10 percent if the electrical generating capscity of the United States. That came close to the entire electrical generating capcity of the Reich. The Japanese were also interested in nuclear weapons. The Japanese began mining uranium at Konan, North Korea, which now is the source of the uranium for North Korea's atomic bombs. The Japanese before the NAZI surrender had the Germans attempt to ship uranium to them by U-boats.


Belgium did not have a nuclear weapons program during World War II, but it did play an important role in both the American and German nuclear programs, This was because Belgium was an important producer of uranium. Uranium was a little-used mineral in 1940. The uranium came from a mine in the Katnga province of the Belgian Congo. The mine was owned by the Grande Union Miniere du Haut Katanga. It was kniown as Shinkolobwe and was one of the few sources of radium, believed at the time to be a miracle cancer cure, at that time. Thus the Belgian Congo in the heart of AFrica of all places became a entity of enormous strategic importance. After the German invasion (May 1940), Congo authorities declared their loyalty to the London-based Belgian Governmernt-in-Exile. Thus the Americans could access ore from the mine and the German U-boats failed to block shipments. The Germans were able, however, to seize stocks of ore from the mine thrat were in Belgium. The only customer of the Grande Union Miniere du Haut Katanga was the United Miniere Company in Brussel. It was was taken over by the Germans and the stockpiles of Uranium ore in Belgium seized. The ore would be used for the German atomic bomb project. The Shinkolobwe mine in the Congo closed after the German invasion (May 1940), but there was about 1,250 tons ore that had been mined. A Belgian businessman and mining executive, Edgar Sengier, at the time of the German invasion lived in the United States. He purchased all of the uranium ore that had been brought to the surface. He shipped it by rail across Portuguese Angola to the port of Lobiro and then by freighter to New York. He stored it at warehouse on State Island. We do not know if he was promoted to do this by U.S. authorities or simply figured out that it would become valusable when America entered the War. At any rate, after the United States decided to build a bomb, the Manhattan Project managers were astoinished to find large quantities of uranium ore sitting in New \Yprk warehouse,


The idea of an atomic bomb also was developed in British. Again it was refugee scientist who conceived and promoted the idea. The Austrian physicist Otto Frisch working with Lise Meitner, A German Jew who narrowly managed to escape the NAZIS, had accuately described what happens when a uranium atom is split. Frisch also escaped the NAZIs and reached Britain and was working at Birmingham University. He was staying with a long-time friend, physicist Rudolf Peierls--another emogre scientist. As a result of their work, they concluded that an atomic bomb could be built. It was Frisch who coined the term nuclear fission. They jointly authored a paper describing the process and took it to the British authorities. This was the first actual plan for building an atomic bomb. The British set up a committee to work on a bomb project (April 1940). The British did not have the enormous resources needed to build an atomic bomb. The Americans did, but were undecided. The British helped to convince the Americans that this was a project of great importance. Atomic research continued in England until 1943 when the Brishish effort became incorporatred into the American Manhattan Project. [Dean, p. 259.] The Manhattan Project would become a joint Anglo-American project with British scientists playing an important role. One of those scientists would pass on important information to the Soviets.


Prospector Gilbert Labine discovered an ore vein containing silver and pitchblende in Canada (1930). The discovery permitted the development of the Eldorado Mine and the town of Port Radium. Labine fonded a company, Eldorado Gold Mines. Work at the Eldorado Mine began producing silver and radium (1933). At the time, the El Dorado mine was the only source of radium outside of the Belgian Congo. Radium at the time was used in medical treatment as well as watch dials. The Eldorado Mine closed as a result of World War II disruoting European markets and an over-supply of radium (1940). With the Manhattan Project and the American intetest in uranium, the mine was reopebned (1942). The mine was operated by the Eldorado Mining and Refining Ltd., a federal crown company. An important refining facility was opened at Port Hope, Ontario. The mine closed as the ore vein was exausted (1960). The Canadians were not just involved in mining uranium. Canada plyed an importaant role in the Allies nuclear effort. The National Research Council sponsored nuclear experiments (1940). The Canadiand with British assistabce opened a laboratory at the University of Montreal (1942). . Canadian abd British scientists working at Montreal project collaborated with Fermi's team in Chicago. The Canadians began operating the first experimental reactor outside the United States at Chalk River (fall 1945). They activated a larger reactor, at the time the world's largest (1947). [Dean, pp. 260-262.]


The first know deliberate mining of radioactive ores occurred at Jáchymov (Joachimsthal). This is a silver-mining city in what was at the time Bohemia in the Austro-Hungarian Empire. It was pitchblende from Jáchymov that Marie Curie used to isolate the element radium--a product of the natural radioactive decay of uranium. Until World War II uranium mining was done primarily for the radium content. Radium was thought to have curative value and was used as a paint for luminous watch dials and other instruments. The uranium by product was used as a yellow paint pigment. After World War I, the mine passed to the new Czechoslovak state (1919). It was acquired by the Germans when they invaded Czechoslovakia.


Niels Henrik David Bohr (1885 – 1962) was one of the most respected neuclear pysicist in Europe. He major major contributions to both atomic structure and quantum mechanics, He was awarded the Nobel Prize in Physics (1922). Bohr mentored many of the principal European nuclear pysicists from Copenhagen insitute. He along with other pysicists closely followed the developments in Germany. The Germans seized Denmark without a fight (Aoril 1940). One of the celebrated questions about the race for the atmoic bomb is the intentions of German pysicist Werner Heisenberg when he traveled to Copenhagen to meet with Bohr. Heisenberg was one of the phyicista Bohr had mentired. As a result of this and Bohr's Jewish mother, he escaped to Sweden (1943). He colaborated in the Manhattan Project.


French scientists played aleading role in the early research on nuckear physics. Henri Becquerel's discovered natural radioactivity (1890s). Pierre and Marie Curie were leading scientists working on nuclear physics. The Joliot-Curies were among the important nuclear phyicists at the time German scientists first demonstrated the potential of nuclear fusion (1939). The French Government was concerned about the possibility of nuclear weapons, but was so behind it conventional weapons that no attempt was made to launch a bomb project. They were concerned enough, however, to spirit heavy water out of Norway. Deuxième Bureau (French intelligence) successfully removed 185 kilograms of heavy water from the plant. Norway was still neutral at the time. The plant's managing director, Aubert, agreed to loan the heavy water to the French for the duration of the war. This was to ensure that it did not fall into German hands. The French secretly transported it first to Oslo and then on to Perth, Scotland and finally to France. Nobel prize winner Frédéric Joliot-Curie prepared to use heavy water, before the German invasion (May-June 1940). As the Germans poured into France, Joliot-Curie diapatched one of his key associates, Hans von Haben to England with the heavy water. An Anglo-French team at Cambridge achieved a chain reaction. [Sulzberger, p. 144.] The German occupation put an end to French nuclear research. nJoliot-Curie joined the French Communist Party (PCF) (1942). This shows a major problems the Germans faced. There were researchers throughout occuipied Europe (Denmark, France, Italy, and other countries) that could have assisted in a German bomb project. Most were, however, for the most part anti-NAZIs and uninterested, even unwilling to work for the Germans. And the Germans were not interested in involving foreign scientists in such sensitive research. After liberation, the Provisional Government of the French Republic (GPRF) created the Commissariat à l'Énergie Atomique (CEA) governmental agency, and appointed Joliot-Curie high-commissioner (October 1945).


Nuclear psyicists in several countries began working on atomic energy before the War. Quite a number were Jews to the extent that German Führer Adolf Hiltler called nuclear physics "Jewish phsycics". The Germans were the leaders in this work and among their most important researchers was a female Jewish pysicist whose colleages helped her escape the Reich. After the outbreak of World War II, the focus shifted to weapons research. It is widely assumed that the Germans did not produce an atmoic bomb during World War II because they lacked the resources to devote to the project during the War. The actual reason is much more complicated. The Germans were certainly limited by the massive industrial requirements of the industry. There were, however, other factors. Tremendous resources were available to the NAZIs. Many were poorly utilized. There was a general German hesitation to conduct weapns research in foreign institutes. Some claim that the leading German scientists leading the research now a fruitless path on purpose. There is little evidence to substantiate this claim. We do know that other factors affected the NAZI bomb program. Driving out leading physicists because they were Jews or sympathetic to the Jews deprived the NAZIs of some of the greatest minds in physics. The failure to use the sciences of captive nations was another factor. Also Hitler was uninterested in long-term projects.


The best known Italian nuclear phyicist was Erico Fermi, but he worked with the Americans as part of the Manhattan Project. Fermi working at the Iniversity of Chicago achieved a controlled chain reaction in an atomic pile December 1942). American phyicist sent the now famous message, "The Italian Nacvigator has just lanbded in the New World. The Natives are friendly." [Sulzberger, p. 144.]


There are many unanswered questions about the German atomic bomb program. Even less is known about the Japanese program. The Japanese were also interested in nuclear weapons. Japan had nuclear scientists who learned about the German expeiments and were aware of the weapons potential. Both the Japanese Army and Navy has small atomic weapons program. There is considerable controversy concening the progress made. The Japanese began mining uranium at Konan, North Korea. The mine an research facility was seized by the Soviets after they declared war on Japan (August 1945). Konan is now the source of the uranium for North Korea's atomic bombs. Unlike the Anglo-American relationship, there sees to have been relatively limited scientific cooperation between Germsany and Japan. What did occur was primarily German technology delivered to Japan. The Germans at first wanted to be paid. And they were concerned about the future relationship between the two countries. As the War went against Germany, the Germans were more willing to transfer technology. The problem was how to transfer it. Mine laying submarines were converted to carry cargos. We know that shipments took place, because of German accounts and the fact that German submarine crews were found in Japan after the War. And more importantly, one of the submarines, the U-234, surrended to the U.S. Navy after the NAZIs surrenderd (May 1945). It contained enriched uranium as part of the cargo. Just what cargos got through to Japan earlier is not known with any surity. The U-234 incident clearly shows that uranium was a priority concern of the Japanese by the end of the War.


There was only one place in Europe capable pf producing large quatities of heavy water--Telemark, Norway. And the NAZIs had occupied Norway (April 1940). The Norwegians had constructed the Vemork hydroelectricity power plant outside Rjukan in Tinn. The 60-MW Vemork plant was named after a waterfall, but is often referred to as Telemark which is the name of the county. The plant was constructed for Norsk Hydro (1911). The primary purpose was to produce hydrogen needed to manufacture fertilizer. Norsk Hydro built the first commercial plant at Vemork specifically to produce heavy water (1934). It had the capacity to produce of 12 tons of heavy water annually. Just before the German invasion, Deuxième Bureau (French intelligence) successfully removed 185 kilograms of heavy water from the plant. Norway was still neutral at the time. The plant's managing director, Aubert, agreed to loan the heavy water to the French for the duration of the war. The French secretly transported it first to Oslo and then on to Perth, Scotland and finally to France. Of course the French could not conceive of Frebch capitulation to the Germans. Many Norwegian scientists fled Norway when the NAZIs occupied the country. Professor Leif Tronstad, designer and construction supervisor of the Vemork plant, remained with his family in Norway. He managed to inform the British of German plans to increase production of heavy water. A double agent informed Tronstad that the Germans had learned of his illegal transmissions and he had to flee to Britain (September 1942). RAF reconisance flighs provided additional information. (A HBC reader is trying to acertain if the RAF used thecAmerican P-51 Mustangs fitted with extra fuel tanks (150 gallon) in the ammo/gun bays during 1942-43. [Bybee]) British and Resistance attacks prevented the Germans from getting much of the plant's production back to the Reich. Norwegian resistance damaged the plant. The attacks were code named Freshman, Grouse and Gunnerside. The Gunnerside attack targeted the fuel cells and destroyed the plant woks (February 1943). The Germans attempted to repair the damage and had the plant opersational agin (August 1943). The resistance kept the Allies informed of German activities. The Americans bombed the plant (November 16, 1943). The plant was so severly damaged that Göring, responsible for the bomb project, ordered the heavy water production effort moved back to the Reich. About 14 tons of heavy water survived the bombing. The Germans attempted to transpoort the drums of heavy water protected by SS guards by rail and ferry (February 20, 1944). The resistance blue up the ferry. The Germans were only able to salvage three drums. [Drummond] This ended German efforts to get Norwegian heavy water to the Reich.

Soviet Union

The Soviet Union was not giving any significant attention to nuclear physics befor the advent of World War II. Soviet researchers were focused on more practical, industrial areas. Researchers during the Great Purges did not want to explore innovative ideas least they be accused of fastening state resources. There was also the danger of Lysenkoism which severely damaged early Soviet science. Thus Soviet physicists, influenced by Abram Ioffe, attempted to emphasize research designed to strengthen the Soviet economy and industry. They intentionally avoided research projects that could be suspectable of being criticized as "theoretical" and "impractical". And this was how nuclear physics was perceived. The German discovery of nuclear fission (1939) caused enormous interest in world-wide scientific community, including Soviet scientists. The theoretical possibility of a nuclear weapon was immediately apparent. Nuclear scientists did not think it was a practical development in the foreseeable future. Yakov Frenkel did the first theoretical Soviet work on fission (1940). Georgii Flerov and Lev Rusinov reached important conclusions about a nuclear chain reaction. The Soviet Union established a State Fund for Uranium Metal (Spring 1940). The very preliminary work was but its early nuclear research was interrupted by the German invasion (June 1941). The entire Soviet industrial and research establishment was devoted to the immediate task of defeating the Germans. Any major activity in the Soviet Union required Stalin's approval. Stalin was first informed of American nuclear research by Georgii Flerov (April 1942). Flerov noted that physics journals in American, Britain, and Germany were no longer publicizing papers on nuclear fission. And leading physicists were no longer publishing anything. The reasons were obvious. Flerov urged Stalin to immediately launch a Soviet nuclear program. The massive effort needed to fight the Germans on the Eastern Front, however, meant that resources were not available for any substantial effort. Stalin did assign Foreign Minister Vyacheslav Molotov to begin a program (1943). Molotov was replaced by NKVD head Lavrentii Beria (1944). The Soviet program did not begin to make major progress until well after the War (1947). [Gueron, p. 62.] The scientific head of the project was the nuclear physicist Igor Kurchatov. Other researchers Yuli Khariton, Yakov Zeldovich and Andrei Sakharov who would later become the lead theoretical designer of the hydrogen bomb ans subsequently a major dissident. While resources were at first limited, the NKVD was able to provide a great deal of information about the Manhattan Project from its spy network in America.

United States

The American Manhattan Program was the largest weapons development program in history. It was initiated by President Roosevelt when work done by German physicists led to concern that the NAZIs might build an atomic bomb. Important scientists in 1939 concluded that German scientists had begun to develop an atomic bomb for the NAZIs. These scientists induced President Roosevelt to launch an American atomic bomb project. The project was, however, given serious attention only after the Japanese attack on Pearl Harbor bringing America into the war. General Leslie R. Groves (1896-1970), Deputy Chief of Construction of the U.S. Army Corps of Engineers, was assigned to oversee the project. The Manhattan Project us named after the New York borough where the first office headquarters was located and began June 1942. Groves had just completed another rush project, the construction of the Pentagon. He considered himself an astute judge of men and chose Robert J. Oppenheimer (1904-1967)to lead the scientific team. Oppenhimer was a respected, but relatively unknown theoretical physicist. Enrico Fermi and Leo Salard working in a converted squash court beneath the University of Chicago's carried out the first controlled nuclear reaction occurred confirming that nuclear fission could unleash huge amounts of energy. The major difficulty in building an atomic bomb was in obtaining the required quantity of fissionable material. A huge facility was built an Oak Ridge, Tennessee to separated the U-235 isotope needed for the bomb from the more common U-238 isotope. The Hanford Engineer Works was built in Washington to produce plutonium. Groves chose Los Alamos, New Mexico as a location to actually develop and assemble the bomb or "gadget" a it was called. This isolated town had by March 1943 been turned into a high-technology boomtown. The Y-12 Plant at Oak Ridge provided the bomb-grade U-235 used for the Little Boy bomb. The Harford plant provided the Plutonium used in the Fat Man bomb.


Dean, Gordon . Report on the Atom (New York: Alfred Knopf, 1959).

Drummond, John D. But for These Men.

Gueron, J. "Atomic Energy in Continental Western Europe," Bulletin of the Atomic Scientists, VOl. 26, No. 6, June 1970.

Sulzberger, Cyrus Leo. World War II.


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Last updated: 3:16 PM 1/9/2016