The Science Of War |
"Experiments by Hahn and Strassman...led to the conclusion that nuclear bombardment of natural uranium by slow neutrons causes explosion or fission of the nucleus, which splits into particles of smaller charge and mass with energy being released in the process. Later it was found that the neutrons were emitted during the process and that the fission was principally confined to the uranium isotope U235 present as 1/139 part of the natural uranium." |
Fission
"The direct energy release in the fission process is of the order of 170MEV per atom. This is considerably more than 10,000,000 times the heat of reaction per atom in ordinary combustion processes." "In such a system, the fission neutrons produced give rise to new fission neutrons in sufficiently large numbers to overcome the neutron losses in the system. Since the result of the fission of the uranium nucleus is the production of two lighter elements with great kinetic energy, plus approximately 2 fast neutrons... a large amount of power could be made available..." |
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Moderators
"The secondary neutrons thus produced...have a high average energy, and must be slowed down...in order to be in condition to cause...fission in other U235 nuclei. This slowing down, or moderation of the neutron energy, is accomplished by passing the neutrons through a material where the neutrons are slowed by collision. Such a material is known as a moderator." "Light elements, such as deuterium, beryllium, or carbon, the latter preferably in the form of graphite, can be used as slowing agents....Both beryllium and deuterium are expensive and not readily available in large quantities. However carbon, in the form of graphite is a relatively inexpensive, practical, and readily available agent for slowing fast neutrons..." |
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Student Interview with Professor Anil Prinja, Ph.D.
University of New Mexico, Department of Chemical & Nuclear Engineering
University of New Mexico, Department of Chemical & Nuclear Engineering
Reactors and bombs
"the Germans rejected the separation of uranium isotopes as too difficult. They saw the fissionability of plutonium as the key to the entire project. Once you had a chain reaction you could make plutonium, and once you had plutonium, you could make a bomb. However, if they had achieved the reactor, they would have found that the road from there to a bomb was still full of obstacles."
Hans Bethe
"The German Uranium Project": Physics Today, 2000
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