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The multiplication factor, k, is defined as (see nuclear chain reaction): k = number of neutrons in one generation / number of neutrons in preceding generation . If k is greater than 1, the chain reaction is supercritical, and the neutron population will grow exponentially.
During induced fission, a compound system is formed after an incident particle fuses with a target. The resultant excitation energy may be sufficient to emit neutrons, or gamma-rays, and nuclear scission. Fission into two fragments is called binary fission, and is the most common nuclear reaction.
The four-factor formula, also known as Fermi's four factor formula is used in nuclear engineering to determine the multiplication of a nuclear chain reaction in an infinite medium. Four-factor formula: k ∞ = η f p ε {\displaystyle k_{\infty }=\eta fp\varepsilon } [ 1 ]
Nuclear engineering was born in 1938, with the discovery of nuclear fission. [7] The first artificial nuclear reactor, CP-1, was designed by a team of physicists who were concerned that Nazi Germany might also be seeking to build a bomb based on nuclear fission. (The earliest known nuclear reaction on Earth occurred naturally, 1.7 billion years ...
Nuclear weapons employ high quality, highly enriched fuel exceeding the critical size and geometry (critical mass) necessary in order to obtain an explosive chain reaction. The fuel for energy purposes, such as in a nuclear fission reactor, is very different, usually consisting of a low-enriched oxide material (e.g. uranium dioxide, UO 2 ...
Xenon-135 (135 Xe) is an unstable isotope of xenon with a half-life of about 9.2 hours. 135 Xe is a fission product of uranium and it is the most powerful known neutron-absorbing nuclear poison (2 million barns; [1] up to 3 million barns [1] under reactor conditions [2]), with a significant effect on nuclear reactor operation.
Shutdown is the state of a nuclear reactor when the fission reaction is slowed significantly or halted completely. Different nuclear reactor designs have different definitions for what "shutdown" means, but it typically means that the reactor is not producing a measurable amount of electricity or heat and is in a stable condition with very low reactivity.
A conventional nuclear reactor's nuclear fuel possesses self-regulating properties such as the Doppler effect or void effect, which make these nuclear reactors safe. In addition to these physical properties of conventional reactors, in the subcritical reactor, whenever the neutron source is turned off, the fission reaction ceases and only the ...