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The six-factor formula is used in nuclear engineering to determine the multiplication of a nuclear chain reaction in a non-infinite medium. The formula is | 1.65 |- | | The thermal utilization factor | Probability that a neutron that gets absorbed does so in the fuel material. | | 0.71 |- | | The resonance escape probability | Fraction of fission neutrons that manage to slow down from fission to thermal energies without being absorbed. | | 0.87 |- | | The fast fission factor (Epsilon) | | | 1.02 |-| |- | | The fast non-leakage probability | The probability that a fast neutron will not leak out of the system. | | 0.97 |-| |- | | The thermal non-leakage probability | The probability that a thermal neutron will not leak out of the system. | | 0.99 |- |} The symbols are defined as: *, and are the average number of neutrons produced per fission in the medium (2.43 for Uranium-235). * and are the microscopic fission and absorption cross sections for fuel, respectively. * and are the macroscopic absorption cross sections in fuel and in total, respectively. * is the number density of atoms of a specific nuclide. * is the resonance integral for absorption of a specific nuclide. * *. * is the average lethargy gain per scattering event. * *Lethargy is defined as decrease in neutron energy. * (fast utilization) is the probability that a fast neutron is absorbed in fuel. * is the probability that a fast neutron absorption in fuel causes fission. * is the probability that a thermal neutron absorption in fuel causes fission. * is the geometric buckling. * is the age to thermal. * *. * * is the evaluation of where is the energy of the neutron at birth. ==Multiplication== The multiplication factor, k, is defined as (see Nuclear chain reaction): If k is greater than 1, the chain reaction is ''supercritical,'' and the neutron population will grow exponentially. If k is less than 1, the chain reaction is ''subcritical,'' and the neutron population will exponentially decay. If k = 1, the chain reaction is ''critical'' and the neutron population will remain constant. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「six factor formula」の詳細全文を読む スポンサード リンク
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