German nuclear energy project

As uranium project, all work in Germany is called during the Second World War, in which the nuclear fission discovered in 1938 should be made ​​technically available. Main objective was to assess the possibilities for building a nuclear weapon and to build a demonstration reactor core. Despite some successes, it has not allowed the scientists to war to establish a controlled self-sustaining nuclear chain reaction in such a reactor. There is no evidence that the war against smaller nuclear weapon ntests were made ​​as sometimes claimed.

During the war, the industrial production facilities were destroyed by the Allies. End of the war eight scientists involved in the uranium project were taken from the Alsos Mission and interned at Farm Hall (England). Others, such as Manfred von Ardenne, were fixed by Soviet forces. The experimental setups of the uranium project were dismantled and confiscated the materials. The scientists were released after the war and returned, partly after years of conscription in the Soviet Union to Germany.

Other parties of interest:

The most important scientists involved in the uranium project were

•Werner Heisenberg, Carl Friedrich von Weizsäcker and Karl Wirtz at the Kaiser Wilhelm Institute for Physics in Berlin-Dahlem, later in Hechingen,

•Robert DOEPEL in experimental-physics institute of the University of Leipzig with Heisenberg in theoretical physics institute until it was taken over the leadership of the Berlin KWI for Physics (mid-1942),

•Kurt Diebner on Heereswaffenamt in grief Village Well in Berlin (later in Stadtilm)

•Harteck Paul and Wilhelm Groth at the University of Hamburg.

More indirectly involved institutions were the Kaiser Wilhelm Institute for Chemistry (Otto Hahn, Max von Laue and Horst Korsching) in Berlin-Dahlem, the Research Laboratory for Electron Physics by Manfred von Ardenne in Berlin light field, and the universities of Heidelberg (Walther Bothe and Wolfgang Gentner) and Göttingen (Hanle Wilhelm and Georg Joos).

Involved from the industry side on uranium project were:

•the Auergesellschaft in Oranienburg for the supply of uranium ore,

•the German gold and silver scabbard-Anstalt (Degussa) in Frankfurt, Germany for the production of pure uranium,

•the Norwegian Hydro Electric Company (Norsk Hydro) at Rjukan in Norway for the production of heavy water and

•the Leuna works of IG Farben in Merseburg for further production of heavy water.

Early history

In 1934, the Italian physicist Enrico Fermi had at the Sapienza University of Rome chemical elements, including uranium, irradiated with neutrons s won it by nuclear reaction artificial radioactive elements. The Austrian physicist Lise Meitner and the German chemist Otto Hahn examined in the following years at the Kaiser Wilhelm Institute for Chemistry in Berlin-Dahlem Fermi’s experiment e and believed in the following years a number of new elements to have demonstrated so-called transuranic elements.

Lise Meitner had to leave Germany in July 1938 because of her Jewish ancestry and was able to emigrate to Sweden, thanks to Otto Hahn Help about Holland. Hahn continued to experiment in Berlin with his assistant Fritz Strassmann. On 17 December 1938 succeeded the first time the detection of neutron-induced fission of uranium isotopes based on barium, which originated as a cleavage product s the bombardment of uranium with neutrons. In a letter to Lise Meitner, who wanted to celebrate Christmas near Gothenburg together with her ​​nephew Otto Frisch, Hahn described two days later, his crucial experiments and spoke for the first time by a bursting of the uranium nucleus. He published his findings in a paper at the 6th January 1939 in the journal Science published. Another essay tap, in which he pointed out the possibility of energy with the help of a chain reaction, followed on 10 Februar 1939.

In January 1939, Meitner and Frisch managed a first nuclear-physical interpretation of the results. In fact, the uranium atoms were “shattered” into smaller components, as it had initially formulated Otto Hahn. They submitted on 16 January 1939 a short note in the journal Nature, which on 11 Appeared in February 1939. Freshly informed the Danish quantum physicist Niels Bohr, who already on tap discovery 26 January 1939 announced at the Fifth Conference of Theoretical Physics in Washington, DC made. Several U.S. American physicist could repeat valve results immediately. Various U.S. newspapers then reported on their results.

The French physicist Frédéric Joliot-Curie was able to repeat experiments tap in March 1939 at the Collège de France in Paris. He found that for every two to three uranium fission neutrons are released, which is given the possibility of a chain reaction by using these new neutrons split other uranium nuclei. Since the fission of a uranium nucleus releases a relatively large energy, so that the theoretical possibility of a technical use of nuclear fission as an energy source or as a weapon with the physicists of the western world had known since the spring of 1939.

Establishment of the uranium Association

In April 1939, the Göttingen physicist Wilhelm Hanle was in a colloquium lecture on the peaceful use of nuclear fission in a “uranium machine”, ie a nuclear reactor before. His colleague Georg Joos heard this speech and reported on 22 April 1939 in the Reich Ministry of Education along with Hanle on the technical but also the military potential of nuclear fission. The Ministry responded quickly, as early as 29 April 1939 under the leadership of Abraham Esau, the then President of the Physico-Technical Institute, an expert conference in the Reich Ministry of Education convened in Berlin. Besides Hanle and Joos, the participants were physicists Walther Bothe, Robert DOEPEL, Hans Geiger, Wolfgang Gentner and Gerhard Hoffmann at the Conference. Hahn was absent from this meeting, he was even reprimanded for publishing its crucial discovery in absentia. The physicists gathered at this conference summarized the following decisions:

•the preparation of a nuclear reactor’s (called “uranium burner”)

•ensuring all uranium stocks in Germany and

•bringing together the leading German nuclear physicist to a research group.

This group was formally called “Association of Nuclear Physics”, she was informally known as the first “uranium club”. The research should be promoted, especially at the Physico-Technical Institute in Berlin and at the University of Göttingen.

At the same time the Supreme Command of the Army was preparing an appropriate research projects. The Hamburg physical chemist Paul Harteck and his assistant Wilhelm Groth had 24 April 1939 written to the defense ministry, the latest developments in nuclear physics could allow an explosive that would surpass the effect of conventional explosives to many times. This letter eventually landed at Kurt Diebner to those skilled in the Army for explosives and nuclear physics. This means immediately called for the army to you to set up a laboratory in grief village south of Berlin can. Diebner was then appointed to head a newly established nuclear research department in the Army Ordnance Department. At the same time ordered the army command of the Physico-Technical Institute to cease uranium research trials immediately. Henceforth, all utterances were to uranium reactors and uranium weapons as secret.

In September 1939, immediately after the war began, Germany’s leading nuclear physicists to Berlin in the Kaiser Wilhelm Institute for Physics have been cited. Diebner designed together with the nuclear physicist Erich Bagge on 20th September 1939 with a program entitled “Preparatory work plan to hold trials for the harnessing of nuclear fission”, which should coordinate the research. The goal of the program was to achieve a controlled chain reaction in a uranium reactor. Few physicists heeded the call to Berlin, but all agreed to participate in the project. Among those who moved to Berlin were Carl Friedrich von Weizsäcker and Karl Wirtz. In addition to their scientific curiosity was, according to their own statements, exemption from military service, the reason for the move.

The former director of the Kaiser Wilhelm Institute, the Dutch physicist Peter Debye, was urged to accept or abdicate the German citizenship. However, Debye refused and returned after a stay in the United States in January 1940 not to return to Germany. As his successor suggested the Heereswaffenamt Diebner, which was rejected by the Kaiser Wilhelm Society. Diebner was then used for the Debye length of absence as acting director. In addition, however, the theoretical physicist and Nobel laureate Werner Heisenberg was brought in as a consultant to the Institute. Some time later, on 1 October 1942, Heisenberg was appointed as the new head of the Institute.

The results of the research were published in the Nuclear Physics research reports, an internal publication series, which was classified as top secret. The research reports had a very limited distribution, not even the authors themselves were allowed to keep copies.

Selection of moderator

In a report to the Army Ordnance Office on 6 December 1939 Heisenberg described the possibility of technical energy using uranium fission in more detail. He showed that one could use this natural uranium, if you compare it with another substance (the moderator) combined, which slows down the neutrons released during fission, but little is absorbed. For this purpose, either heavy water or particularly pure carbon can be used. Several research institutes in various substances have been studied as a potential substance for braking uranium reactor. In Heidelberg, Walter Bothe tested graphite, while Heisenberg calculated the values ​​for heavy water.

Bothe came to the result, graphite is due to high neutron absorption is not very useful, but could be just barely used only for emergency. (This measurement result was later recognized as wrong. It is based on have not noticed a contamination of the graphite used with the strong neutron absorber boron to oral tradition.) On the other hand, Heisenberg found that heavy water had originally accepted as an even better effect. So the decision was made ​​in favor of heavy water.

When three years later started the Manhattan Project was the U.S., however, graphite – whose procurement is much easier – the successful development of reactor used at the beginning (see Chicago Pile).

Material procurement

For the operation of a uranium reactor several tons of both high-purity uranium and very pure heavy water were needed. Both materials were difficult to obtain in large quantities at the time.


The Army Ordnance Department initially requested the extradition of the total uranium resources of the Physico-Technical Institute. This demand came after Esau unwillingly after the research was to him indeed been taken. In addition, the Berlin Auer company was commissioned to deliver several tons of uranium oxide. The uranium came from the uranium mines in Jáchymov who have been exploited after the German annexation of the Sudetenland in 1938 by the Auer Company. Within weeks, the company built in Oranienburg an operation on a monthly production capacity of about one ton of uranium oxide. The first delivery to the Army Ordnance Department was held at the beginning of 1940.

End of May could be ensured during the occupation of Belgium most of the uranium deposits of the Belgian company Union Minière du Haut Katanga, the imported uranium ore from the Belgian Congo. During the next five years, the German troops managed 3,500 tons of uranium compounds from Belgium to the salt mine Staßfurt. For these stocks, the Auer-art breastfeeding until the war’s other uranium demand.

Heavy water

Beginning of the war produced only the Norwegian Hydro Electric Company (Norsk Hydro) at a plant in Vemork in Rjukan heavy water in appreciable quantities. The work was used primarily for the production of fertilizers and heavy water supplied only as a byproduct. In the years 1934-1938 the work of just 40 kg heavy water was produced in late 1939, the monthly production reached a maximum of ten kilograms.

Since the structure of its own heavy water production in Germany seemed too expensive, took a delegation of IG Farben with Norsk Hydro’s contact with the target, the entire stock of 185 kg to purchase heavy water. However, the French secret service came before, and the German negotiators agreed with management to create all the heavy water to Paris Frédéric Joliot-Curie, who conducted his own experiments on fission of uranium there.

In April 1940, the German army occupied Norway and marched on 3 May 1940 in Rjukan one. The only heavy water factory in the world fell undamaged into German hands, but it was found that the entire stock had been issued to heavy water. This was not only disappointing for the army command, but also a warning that the Allies were also interested in the use of nuclear fission. As a result, the heavy-water production was increased in Vermork to 1,500 kg per year.

First attempts

Beginning of 1940, worked alongside Werner Heisenberg at the Kaiser Wilhelm Institute in Berlin and Kurt Diebner village in grief, Paul Harteck at the University of Hamburg at a uranium reactors. At this point, the uranium and heavy water supplies were severely limited in Germany, and began a struggle for resources between the institutions. As Heisenberg asked the Army Ordnance Office 500 to 1000 kg of uranium oxide in April 1940, Diebner wrote back to him that he should agree with Harteck who had just asked himself for 100 to 300 kilograms. Harteck wanted in a test reactor in his basement Institute uranium oxide in solid carbon dioxide (dry ice) beds, which he was to receive from the Leunawerke n of IG Farben from Merseburg. Harteck was in a hurry, because the carbon block only lasted over a week, and he asked Heisenberg to give him the uranium oxide until he was finished with his attempt. End of May finally arrived 50 kg of uranium oxide in Hamburg, considerably less than Harteck had hoped for. Together with an additional supply of Auergesellschaft him were a total of only 185 kilograms of uranium oxide available – far too little to bring about a nuclear chain reaction.

Mid-June 1940 was Paris and a short time later met the director of the Research Department of the Army Ordnance Office Erich Schumann and Kurt Diebner one there to visit Joliot-Curie in his laboratory at the Collège de France. The French physicist who fled not like his colleagues in London, and Diebner could get him to stop work on non-military projects. Joliot-Curie had a particle accelerator (cyclotron) half completed, with whom he would start a chain reaction. Diebner promised to complete the unit, and in July began a Parisian working group under the direction of Wolfgang Gentner with the work.

In parallel, a laboratory was set up in July 1940 on the grounds of the Kaiser Wilhelm Institute for Biology in Berlin-Dahlem, Germany’s first uranium in the reactor should be. To keep out unwanted visitors, the building was given the code name deterrent “Virus House”. In the fall of 1940, the construction was completed and shortly after the Berlin researchers began with the construction of the kiln uranium.

Way to the atomic bomb

Basically was the German physicists realized that the construction of a nuclear fission bomb, called by scientists “uranium bomb,” enabled, but not with natural uranium.


One possibility would have been to increase greatly according to the proportion of fissile uranium isotope 235 U, which is available only to 0.7% in natural uranium. Work to have been carried out in Kiel, Wilhelm Walcher and Matt also Josef Group at the Kaiser Wilhelm Institute for Chemistry. A proposal for an efficient uranium enrichment in 1942 by the physicist Heinz Ewald Kaiser Wilhelm Institute for Chemistry submitted. He proposed a “atomic conversion plant” before, a sort of mass spectrometer in the ionized uranium atoms accelerated in an electric field and are subsequently separated in a ring-shaped magnetic field based on the differences in the mass numbers (see Figure 97). Manfred von Ardenne, who headed the Research Laboratory for Electron Physics in Berlin light field, took up the idea and built a prototype. M. Walker: German National Socialism and the Quest for Nuclear Power: 1939-1949, Cambridge University Press, 1989.

He was assisted with this project by the head of the Reich Post Ministry’s Wilhelm Ohnesorge. This is similar to the separation plant

Cyclotron, which was finally completed with the funds of the imperial post 1943 Mierdorf. On the site of an air force base near Bad Saarow a ring bunker was found, corresponding to the cyclotron hall in Mierdorf. Whether this system contained a large-scale version of the Isotopenseparators, can only be surmised. But it never came to Germany to Isotropentrennung of uranium on a larger scale such as the hundreds of calutron s in the Manhattan project.


Also from the Research Institute of Ardenne came by physicist Georg Friedrich Houtermans the proposal, 238 U which is also easily fissile plutonium isotope 239 Pu to metal abundances in a uranium reactor from the much more common isotope of uranium. He summed up his theories in a secret research report “On the question of the release of nuclear chain reactions” together. This report had government agencies and some available in Uranverein organized physicists, but was not observed.

Crisis of conscience

The discussion on the proposals for the development of a uranium bomb was sluggish. Some leading German researchers now showed scruples, to what extent they should be involved at all in the uranium project. In the week of 15 to 21 September 1941 Werner Heisenberg went on a proposal and placement of Carl Friedrich von Weizsäcker in Copenhagen, his former mentor, Niels Bohr. About intention of the trip and course of the conversation, there are different statements. The conversation went anyway unpleasant for both sides. According to a 1967 broadcast by the mirror version Heisenberg, Bohr asked if a physicist have the moral right to work in times of war to a nuclear bomb. Bohr replied with the question whether a military use of nuclear fission to Heisenberg’s view was at all possible because. Heisenberg replied that he had recognized the possibility. He proposed that they all scientists in the world could agree to refrain from working on a nuclear bomb. To Heisenberg’s dismay Bohr replied that the military research by physicists is inevitable and correct. Apparently feared drilling, Germany was on the brink of building a nuclear bomb, and suspected that Heisenberg with his proposal would only slow the American advantage in nuclear physics. Heisenberg on the other hand felt let down by Bohr and had to return to Germany empty-handed.

The play Copenhagen by Michael Frayn has this meeting to content.

Also, no “dirty bomb”?

To cause great damage with the help of nuclear fission, a functioning uranium bomb would not have been necessary. Uranium reactors produce radioactive substances that can be used in the application of conventional bombs. Contrary to fears of the Allies there is no evidence to suggest that has worked in Germany at such a “dirty bomb”.

Other reactor experiments

The end of 1941 came the German war economy after the now very stressful Russian campaign under pressure. The uranium project promised not to come in the near future to an application. Therefore, the Army Ordnance Office to dismiss the project out of the control of the army and leave it to the Reich Research Council under the supervision of the Reich Education Ministry decided. The Reich Research Council, the research project was on to his divisional physics and so the uranium project landed at the turn of 1941/42, again with Abraham Esau, who had been withdrawn when the war began. A year later, Esau was even appointed “Plenipotentiary for Nuclear Physics” and from there he was able to control all physical research groups. The German research on the construction of a uranium kiln until then but little progress. The bottleneck of the project was still the lack of heavy water and of highly enriched uranium, of which only a tiny amount had to be won.

Since the materials produced so far are not sufficient and also the investments abroad were vulnerable to attack, trying to boost their output in Germany. With the Leunawerke n the construction of a heavy water plant at Merseburg was agreed. In return Leuna should be informed about the current state of research on energy from uranium. Degussa in Frankfurt was henceforth to obtain the uranium metal. The first deliveries were made ​​to the physical uranium University Institute in Leipzig, so there finally the first uranium reactor in the world could be set in motion. It was designed by Werner Heisenberg, the theorist and implemented together with the experimental physicist Robert DOEPEL.

To clarify the international priorities was mainly a statement of Irving in the epilogue of his book cited in Section 13 1967 at:

“The Germans were the first half of 1942 with their reactors Leipzig L-IV, the first physicist in the world who brought a positive neutron production materialize.”

The same was achieved in the U.S. in late July 1942 Enrico Fermi, the Germans overtook nuclear reactor with his team soon. Fermi, who had a “unique dual talents of theoretical and experimental work”, had worked on the problem since the spring of 1939. He then spoke with Heisenberg in his last visit to the U.S. before the impending war on the dangers, the two were aware of it.

On 4 June 1942 Heisenberg was appointed together with the leading scientists of the uranium project to a secret meeting in Berlin in order to reimburse Albert Speer, the new Reich Minister for Armaments and Munitions report and to supply him with decision-making basis for the future of the German uranium research. On the question of how large a uranium bomb would be, the effect would be enough to destroy a large city, Heisenberg replied, “As big as a pineapple” and probably was referring only to the actual explosive charge. The High Command was impressed, but also got doubts. Heisenberg pointed out that such a bomb could not develop within a few months and their production is economically impossible at the moment. The construction of a nuclear reactor would be opposed by great economic and military importance, particularly for the period after the war. The uranium then project was not adjusted, but not particularly encouraged. Nevertheless, the Spear approved construction of a bunker on the grounds of the Kaiser Wilhelm Institute for Physics in Berlin, where the first major German uranium reactors should be built.

Three weeks later, a momentous accident occurred in the Leipzig research reactor. For the “uranium machine” 750 kg of uranium powder and 140 kg heavy water were filled into two hemispheres firmly bolted together aluminum and these were immersed in a water tank. The experiment seemed to be successful, because more neutrons are produced than consumed, which in previous experiments confirmed definitively. For months, hung the ball to the water tank, up from its 23 June 1942 suddenly escaped hydrogen bubbles. The ball warmed up in the episode, she was taken out of the container, but sunk after an unsuccessful attempt to open quickly in the water container. The ball is heated further until the evening, the water began to boil. A little later, the ball exploded and set the room on fire with burning uranium without the people present (including Heisenberg and the couple DOEPEL) were harmed. Initial attempts to extinguish Döpels were largely unsuccessful. The fire was under his guidance ultimately extinguish the fire, but the fissile material was a lot Uranoxidschlamm nurmehr left. There had been no nuclear chain reaction, but water had seeped into the uranium layer and had formed together with hydrogen and oxygen oxyhydrogen, which fizzled with the uranium. – This accident was the first in a long series of accidents in nuclear plants, which form from water vapor and superheated metal (in this case uranium powder) and or graphite (such as Chernobyl) air likewise explosive gas (oxyhydrogen Water, gas) and were inflamed.

To prevent similar incidents in the uranium project, it was decided to use in future trials nurmehr uranium in the solid form of cast uranium. Heisenberg calculated that about ten tons of cast uranium and about five tons of heavy water would be needed to make the first critical chain reaction possible. While Heisenberg in Berlin-Dahlem experimented with uranium plates, sat in sorrow Diebner village on uranium cubes. However, the two groups did not cooperate, but worked against each other. As Diebner, achieved unexpectedly good results with uranium cubes, which were stored in the frozen heavy water, Heisenberg failed to recognize him and continued to exist on the use of uranium plates and normal heavy water.

Allied attacks on the supply

In the meantime, the Allies had become suspicious that the German researchers worked intensively on a uranium bomb. On the night of 27 to 28 February 1943 succeeded in Operation Gunnerside eight Norwegian saboteurs to penetrate the heavy water plant of Norsk Hydro and 18 electrolysis cells with which the heavy water was separated, to destroy by explosives. In addition, a half-ton is produced heavy water was destroyed. Until April 1943, the damage could indeed be reasonably resolved by the Germans, but a serious blow to the uranium project was added.

On 16 By 1943 Norsk Hydro heavy water factory was finally destroyed by British bombers. Although the heavy water concentration plant in the basement remained intact, the power station had been taken, however, making the whole factory could no longer work. Therefore, the Germans attempted to ship the rest, partially concentrated heavy water by train for further processing in the now nearly completed plant in Leuna Werke Germany. To leave Rjukan, the transport with the train ferry “Hydro” had to cross the lake Tinnsjå. The Allies learned of the plans of the Germans, and the ferry was on 20 February 1944 sunk by Norwegian resistance fighter n. Some of the only partially filled heavy water barrels were rescued by the Germans, but the majority sank to the bottom of the lake.

A little later, another British Bomber Command destroyed in a night raid on Frankfurt, Degussa-works and their uranium production facility n In August 1944, the Leuna works were made, and the IG Farben was subsequently no further interest in the production of heavy water. Thus the summer of 1944 had come to a standstill the entire German uranium and heavy water production. Overall, the German physicist possessed at the end of the war more than 2.5 tons of heavy water, and it was questionable whether this amount would be sufficient for the operation of a uranium kiln.

Transfer of research to southern Germany

On 23 October 1943 Walther Gerlach was appointed head of the Reich Research divisional director of physics and thus uranium project. At the turn of Gerlach took over the post also as agent for Nuclear Physics of Esau, who had made himself unpopular with the management of the Kaiser Wilhelm Society and Albert Speer. In the following period Gerlach failed the funds available to it to research projects with military applications, such as the uranium project or now be used particle accelerators, and put them instead, especially for projects of basic research. On the other hand, he prevented the German physicists were drafted into military service.

When the British air force began their attack on Berlin in the late autumn of 1943, parts of the Kaiser Wilhelm Institute for Physics have been outsourced to Hechingen in southern Germany. Shortly thereafter, the Kaiser Wilhelm Institute for Chemistry went under Otto Hahn in the vicinity of Tailfingen. The other working groups of the uranium project attracted to southern Germany. Diebner moved his laboratory to Stadtilm in Thuringia, Harteck Groth and moved with her ​​new ultracentrifuge only to Freiburg, and to Celle.

Recent attempts

Some physicists, including Heisenberg, Bothe and Wirtz, but initially remained in Berlin and prepared the construction of large uranium reactor is nearly finished bunker. Late 1944 Wirtz could populate the uranium reactors with 1.25 tons of uranium and 1.5 tons of heavy water. This experiment showed a substantial increase of the fed out of a radioactive neutron source neutrons. Wirtz prepared a larger trial. After the Red Army on 30 January 1945 at Kienitz had crossed the Oder, immediately established a beachhead and their advance on Berlin was foreseeable Gerlach gave the order to leave Berlin. The uranium and heavy water were shipped to Diebner to Stadtilm, physicists fled to knitting.

The latest in a long series of experiments should be carried out in a basement rocks in Haigerloch at Hechingen (Württemberg).

The materials were then managed by truck from Stadtilm to Haigerloch. End of February 1945 once the research reactor Haigerloch with 1.5 tons of uranium, and the same amount of heavy water to be taken into operation. However, the materials were not sufficient to make the reactor critical. Heisenberg still trying to get the last supplies of uranium and heavy water from Stadtilm, but the delivery was not more.

The United States has long harbored the fear that the Germans were working on a uranium bomb, and in 1943 established the military Alsos mission. Their goal was to explore the state of the German uranium project to stop the research and the physicist to get hold of. On 23 April 1945 finally reached the Alsos mission Haigerloch. The reactor was destroyed and managed confiscated all materials and research reports and analysis to the United States. The German scientists of the uranium project were arrested. Bagge, von Weizsäcker and Wirtz were passed in Hechingen, Heisenberg in his home Urfeld, Gerlach and Diebner Harteck in Munich and Hamburg. Also been taken up in Tailfingen Otto Hahn, Horst Korsching and Max von Laue.

Interned at Farm Hall

The elite of the German nuclear research was brought to the British Manor Farm Hall, near Cambridge. They spent the time in the idyllic brick building and surrounding gardens with fist ball, billiards, bridge, and discussions. The discussions of the scientists were intercepted and recorded by the British military.

On 6 August 1945 was the officer in charge of the detention Major TH Rittner from London to command, that his prisoners should be heard by 18 clock radio. Rittner should carefully observing the reactions of the men on the messages. Hahn, Heisenberg and Wirtz heard this evening in the office Rittners message the BBC that American scientists had produced a nuclear bomb and has already dropped on a Japanese city.

The reactions of the three Germans were different. Wirtz said that he was glad that they themselves did not have the bomb. Heisenberg gave the message for a “bluff” and doubted at first that a nuclear physics effect in the game is. Otto Hahn was greatly shocked and felt responsible for the death of hundreds of thousands of Japanese. The 21-clock-news brought peace of mind that a uranium bomb was exploded with an explosive force of 20,000 tons of TNT equivalent of Hiroshima.  In the following discussion of Weizsäcker said it was terrible that the Americans had done it and he considered the action is madness. Heisenberg replied, but this is probably the quickest way to end the war. Hahn found himself well in all his fears confirmed that had plagued it since its discovery in December, 1938. He was ultimately just glad that the Germans had not made ​​it.

On 18 November 1945 Hahn learned during his detention that he had been awarded for his discovery in 1938 of the Nobel Prize in Chemistry in the year 1944. On 3 January 1946 the ten scientists from the uranium project were eventually released and returned to Germany.

Soviet atomic bomb project

As well as from the United States a large number (about 300) of German nuclear specialists were spent in the Soviet occupation zone and with their families in the Soviet Union after the Second World War. In addition, the removal of technical equipment of the German uranium project, including the Kaiser Wilhelm Institute for Physics, the Kaiser Wilhelm Institute for Chemistry in the electrical laboratories of Siemens and the Physics Institute of the Reich Postal Ministry was. Overall, three of the four German cyclotron and strong magnets, electron microscopes, oscilloscopes, power transformers and ultra-precise instruments were brought into the USSR. The contribution of the German scientists in the development of nuclear technology for the Soviet atomic bomb project is limited primarily to the production of uranium and the isotope separation. Also significant is the contribution of the first Soviet atomic bomb test – before, as well as the Soviet acquisition of larger amounts of uranium immediately and shortly after the end of World War II – a plutonium-based nuclear bomb.


•Till Bastian: High tech under the swastika.Of the atomic bomb to space travel. Militzke, Leipzig, 2005, ISBN 3-86189-740-7.

•David Irving: The dream of the German atomic bomb. Poppy, Gütersloh in 1967.

•Rainer Karlsch, Zbynek Zemen uranium secrets, Christoph Links Verlag, Berlin 2003, ISBN 3-86153-276 X-

•Rainer Karlsch: Hitler’s bomb. German publishing house, Munich 2005, ISBN 3-421-05809-1.

•Michael Schaaf: Heisenberg, Hitler and the bomb.Interviews with witnesses. Diepholz, Berlin 2001, ISBN 3-928186-60-4.

•Mark Walker: A Blacksmith?Nuclear Weapons and Reactor Research at the Kaiser Wilhelm Institute for Physics. Preprints from the research program “History of the Kaiser Wilhelm Society under National Socialism”. No. 26 Max Planck Institute for the History of Science in Berlin (2005). ( online , PDF, 402 kB)◦the same: The uranium machine.Myth and reality of the German atomic bomb. Settlers, Berlin 1992, ISBN 3-442-12835-8.

•Karl Wirtz: Within physics. Nuclear Research Center Karlsruhe, 1987, ISBN 3-923704-02-X.

•Christian Kleint and Gerald Wiemers (eds): Werner Heisenberg in Leipzig from 1927 to 1942, the Saxon treatises. Acad of Wiss. Leipzig, Math Naturw. Class Vol 58 (1993 H.2), Part I: Contributions to the development of nuclear reactor W. Heisenberg and R. DOEPEL in the Physics Department of the University of Leipzig (1939-1942) – On the 50th anniversary of the first detection of the neutron multiplication in uranium machine. Pp. 11-84.

•Ivan Supek, Leipzig in time and Heisenberg’s dog. U from the novel Otkrice izgulbljeom vremenu (Discovery in the Lost Time). Zagreb in 1987. In: Manfred Schroeder (ed.): One Hundred Years of Friedrich Hund.A look back at the work of an important physicist. News of the Academy of Sciences in Göttingen II Math. Class, born 1996 No. 1, pp. 32-52.

Nuclear weapons program

German Empire (1933-1945)

Science in National Socialism

Military technology (World War II)

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