A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nuclear fission is passed to a working fluid, which in turn runs through steam turbines. These either drive a ship's propellers or turn electrical generators' shafts. Nuclear generated steam in principle can be used for industrial process heat or for district heating. Some reactors are used to produce isotopes for medical and industrial use, or for production of weapons-grade plutonium. As of 2022, the International Atomic Energy Agency reports there are 422 nuclear power reactors and 223 nuclear research reactors in operation around the world.
Werner Karl Heisenberg was a German theoretical physicist, one of the main pioneers of the theory of quantum mechanics, and a principal scientist in the Nazi nuclear weapons program during World War II. He published his Umdeutung paper in 1925, a major reinterpretation of old quantum theory. In the subsequent series of papers with Max Born and Pascual Jordan, during the same year, his matrix formulation of quantum mechanics was substantially elaborated. He is known for the uncertainty principle, which he published in 1927. Heisenberg was awarded the 1932 Nobel Prize in Physics "for the creation of quantum mechanics".
In nuclear engineering, a neutron moderator is a medium that reduces the speed of fast neutrons, ideally without capturing any, leaving them as thermal neutrons with only minimal (thermal) kinetic energy. These thermal neutrons are immensely more susceptible than fast neutrons to propagate a nuclear chain reaction of uranium-235 or other fissile isotope by colliding with their atomic nucleus.
Walther Wilhelm Georg Bothe was a German nuclear physicist know for the development of coincidence methods to study particle physics.
Chicago Pile-1 (CP-1) was the world's first artificial nuclear reactor. On 2 December 1942, the first human-made self-sustaining nuclear chain reaction was initiated in CP-1 during an experiment led by Enrico Fermi. The secret development of the reactor was the first major technical achievement for the Manhattan Project, the Allied effort to create nuclear weapons during World War II. Developed by the Metallurgical Laboratory at the University of Chicago, CP-1 was built under the west viewing stands of the original Stagg Field. Although the project's civilian and military leaders had misgivings about the possibility of a disastrous runaway reaction, they trusted Fermi's safety calculations and decided they could carry out the experiment in a densely populated area. Fermi described the reactor as "a crude pile of black bricks and wooden timbers".
Erich Rudolf Bagge was a German scientist. Bagge, a student of Werner Heisenberg for his doctorate and Habilitation, was engaged in German Atomic Energy research and the German nuclear energy project during the Second World War. He worked as an Assistant at the Kaiser-Wilhelm-Institut für Physik in Berlin. Bagge, who became associated professor at the University of Hamburg in 1948, was in particular involved in the usage of nuclear power for trading vessels, and he was one of the founders of the Society for the Usage of Nuclear Energy in Ship-Building and Seafare.
Nazi Germany undertook several research programs relating to nuclear technology, including nuclear weapons and nuclear reactors, before and during World War II. These were variously called Uranverein or Uranprojekt. The first effort started in April 1939, just months after the discovery of nuclear fission in Berlin in December 1938, but ended only a few months later, shortly ahead of the September 1939 German invasion of Poland, for which many notable German physicists were drafted into the Wehrmacht. A second effort under the administrative purview of the Wehrmacht's Heereswaffenamt began on September 1, 1939, the day of the invasion of Poland. The program eventually expanded into three main efforts: Uranmaschine development, uranium and heavy water production, and uranium isotope separation. Eventually, the German military determined that nuclear fission would not contribute significantly to the war, and in January 1942 the Heereswaffenamt turned the program over to the Reich Research Council while continuing to fund the activity.
Kurt Diebner was a German nuclear physicist who is well known for directing and administering parts of the German nuclear weapons program, a secretive program aiming to build nuclear weapons for Nazi Germany during World War II. He was appointed the project's administrative director after Adolf Hitler authorized it.
Nuclear graphite is any grade of graphite, usually synthetic graphite, manufactured for use as a moderator or reflector within a nuclear reactor. Graphite is an important material for the construction of both historical and modern nuclear reactors, due to its extreme purity and ability to withstand extremely high temperature.
Karl Eugen Julius Wirtz was a German nuclear physicist, born in Cologne. He was arrested by the allied British and American Armed Forces and incarcerated at Farm Hall for six months in 1945 under Operation Epsilon.
Rudolf Heinz Pose was a German nuclear physicist who worked in the former Soviet program of nuclear weapons.
Georg Robert Döpel was a German experimental nuclear physicist. He was a participant in a group known as the "first Uranverein", which was spawned by a meeting conducted by the Reichserziehungsministerium, in April 1939, to discuss the potential of a sustained nuclear reaction. He worked under Werner Heisenberg at the University of Leipzig, and he conducted experiments on spherical layers of uranium oxide surrounded by heavy water. He was a contributor to the German nuclear weapon project (Uranprojekt). In 1945, he was sent to Russia to work on the Soviet atomic bomb project. He returned to Germany in 1957, and he became professor of applied physics and director of the Institut für Angewandte Physik at the Hochschule für Elektrotechnik, now Technische Universität, in Ilmenau (Thuringia).
Walter Herrmann was a German nuclear physicist and mechanical engineer who worked on the German nuclear energy project during World War II. After the war, he headed a laboratory for special issues of nuclear disintegration at Laboratory V in the Soviet Union.
Klara (Minna) Renate Döpel was a feminist and a German lawyer until 1933. Then she married the German nuclear physicist Robert Döpel, and they worked together as a team at Leipzig University studying nuclear reactor configurations for the German nuclear energy project. Klara was killed in an air raid near the end of World War II.
Wilhelm Hanle was a German experimental physicist. He is known for the Hanle effect. During World War II, he made contributions to the German nuclear energy project, also known as the Uranium Club. From 1941 until emeritus status in 1969, he was an ordinarius professor of experimental physics and held the chair of physics at the University of Giessen.
Gerhard Hoffmann was a German nuclear physicist. During World War II, he contributed to the German nuclear energy project, also known as the Uranium Club.
Klaus Paul Alfred Clusius was a German physical chemist from Breslau (Wrocław), Silesia. During World War II, he worked on the German nuclear energy project, also known as the Uranium Club; he worked on isotope separation techniques and heavy water production. After the war, he was a professor of physical chemistry at the University of Zurich. He died in Zurich.
Erich Horst Fischer was a German experimental physicist. He worked at the Kaiser Wilhelm Institute for Physics (KWIP) and contributed to the German nuclear energy project, also known as the Uranium Club. After World War II, he helped rebuild the KWIP branch at Hechingen, was a professor at the University of Tübingen and Ankara University, and then a research scientist for the German firm GKSS.
Oskar Ritter was a German physicist. During World War II, he worked on the German nuclear energy project, also known as the Uranium Club.
Herbert G. MacPherson was an American nuclear engineer and deputy director of Oak Ridge National Laboratory (ORNL). He contributed to the design and development of nuclear reactors and in the opinion of Alvin Weinberg he was "the country's foremost expert on graphite"...
Werner Heisenberg (1933)
Robert Döpel (1935)
Physical Institute Leipzig (1909)
Leipzig uranium machine (1942)
