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Operation Epsilon was the codename of a program in which Allied forces near the end of World War II detained ten German scientists who were thought to have worked on Nazi Germany's nuclear program. The scientists were captured between May 1 and June 30, 1945, [ 1 ] as part of the Allied Alsos Mission , mainly as part of its Operation Big sweep ...
Henry D. Smyth was a professor of physics and chairman of the physics department of Princeton University from 1935 to 1949. [1] During World War II, he was involved in the Manhattan Project from early 1941, initially as a member of the National Defense Research Committee's Committee on Uranium, and later as an associate director of the Metallurgical Laboratory in Chicago.
The discovery of the neutron by James Chadwick in 1932, [1] followed by that of nuclear fission in uranium by the German chemists Otto Hahn and Fritz Strassmann in 1938, [2] and its theoretical explanation (and naming) by Lise Meitner and Otto Robert Frisch soon after, [3] opened up the possibility of a nuclear chain reaction with uranium. [1]
Krypton-85, with a half-life 10.76 years, is formed by the fission process with a fission yield of about 0.3%. Only 20% of the fission products of mass 85 become 85 Kr itself; the rest passes through a short-lived nuclear isomer and then to stable 85 Rb. If irradiated reactor fuel is reprocessed, this radioactive krypton may be released into ...
In nuclear fission events the nuclei may break into any combination of lighter nuclei, but the most common event is not fission to equal mass nuclei of about mass 120; the most common event (depending on isotope and process) is a slightly unequal fission in which one daughter nucleus has a mass of about 90 to 100 daltons and the other the ...
Allied work on nuclear fission had been motivated by scientists, many of whom were refugees from Nazi Germany, who feared a German atomic bomb program was underway. The discovery of fission had taken place largely in Otto Hahn 's Berlin laboratory, and many scientists in the United States held the work of German scientists, especially Werner ...
The largest source of fission products is from nuclear reactors. In current nuclear power reactors, about 3% of the uranium in the fuel is converted into fission products as a by-product of energy generation. Most of these fission products remain in the fuel unless there is fuel element failure or a nuclear accident, or the fuel is reprocessed.
On 22 April 1939, after hearing a colloquium paper by his colleague Wilhelm Hanle at the University of Göttingen proposing the use of uranium fission in an Uranmaschine (uranium machine, i.e., nuclear reactor), Georg Joos, along with Hanle, notified Wilhelm Dames, at the Reichserziehungsministerium (REM, Reich Ministry of Education), of potential military and economic applications of nuclear ...