دانلود رایگان مقاله لاتین نوسان انرژی انشقاقی از سایت الزویر
عنوان فارسی مقاله:
نوسانات انرژی انشقاقی تولید شده در یک سیستم ضرب
عنوان انگلیسی مقاله:
Fluctuations of the fission energy generated in a multiplying system
سال انتشار : 2017
برای دانلود رایگان مقاله نوسان انرژی انشقاقی اینجا کلیک نمایید.
مقدمه انگلیسی مقاله:
1. Introduction
Regarding the random character of neutron multiplication in subcritical systems driven by an extraneous source, so far only the fluctuations of the discrete random variable representing the detector counts have been investigated (Feynman et al., 1956; Williams, 1974; Pázsit and Pál, 2008). For instance, the subcritical reactivity can be determined from the dependence of the variance to mean of the number of detections on the measurement time period T. Theoretically, one can also calculate the moments of the total number of absorptions or fissions; however, these cannot be measured. A continuous random variable of interest is the cumulative energy developed in a chain started by one neutron, or in a subcritical system driven by a source. In particular, the fluctuations of the cumulative energy by fissions in a slightly supercritical system driven by a weak source, or the fluctuations of the time it takes for the system to generate a certain amount of energy, can be of interest, since these can show large variations (Williams, 1974). The question can also be interesting from the practical point of view. Safety regulations determine how much power a reactor may be operated with. Reactors are operated with constant power; however, the generated energy is a random variable with a certain variance. To ensure with a certain confidence that one does not exceed the allowed power limit, one has to operate the reactor with a mean power which is below the nominal value with two or three standard deviations of the fluctuations of the generated power. Intuitively these fluctuations can be expected to be small, but it is advisable to investigate the question theoretically. If the energy generated in fission was constant, then the cumulative generated energy would be also a discrete variable. This variable would be proportional to the number of fissions in the system, the (constant) fission energy being the scaling factor. This is then a classic case, and correspondingly, results on the moments of the number of fissions in such systems are found in the literature (Pázsit and Pál, 2008). The situation becomes though different if the fission energy becomes a continuous random variable. In this case the fluctuations in the energy generated in the fission chain will fluctuate not only because of the fluctuations in the number of fissions during the time period concerned, but also due to the fluctuations in the energy generated in the individual fissions. It is an interesting question how much the existence of the fluctuations of the fission energy influences the fluctuations of the energy generated. To incorporate the fluctuations of the fission energy, the traditional treatment has to be modified from handling only discrete random variables to be able to accommodate also the continuous energy variable. Such a formalism has become recently available. In connection with the description of the stochastic properties of fission chamber signals, a master equation technique was elaborated by the present authors for the distribution of the sum of continuous random functions, associated with the discrete detection events, for both independent and correlated events (Pál et al., 2014; Pál and Pázsit, 2015). The same methodology, used for the description of the statistics of neutron detector signals, with due modifications, can also be used here to calculate the cumulative fission energy generated in a fission chain initiated either by a single neutron or by an extraneous source, as it will be developed in the forthcoming sections. In the numerical computations the well known 200 MeV mean energy per fission has been used, while the second moment of energy per fission has been estimated from the data published in the literature (Crouch, 1977). A comparison with the case of constant fission energy makes it possible to assess the significance of the fluctuations of the fission energy in the fluctuations of the total cumulative energy developed in a fission chain.
برای دانلود رایگان مقاله نوسان انرژی انشقاقی اینجا کلیک نمایید.
کلمات کلیدی:
Fluctuations of the fission energy generated in a multiplying ... - INFONA https://www.infona.pl/.../bwmeta1.element.elsevier-fc2a709c-d4b5-3fde-9d63-98bfb9ad... by L Pál - 2017 - Related articles The formalism accounts for the fact that the fission energy χ is also a random variable, thus the fluctuations of the total energy generated are due to both the ... Fluctuations in Electronic Energy Affecting Singlet Fission Dynamics ... pubs.acs.org/doi/abs/10.1021/acs.jpclett.5b02678 by Y Fujihashi - 2016 - Cited by 5 - Related articles Jan 6, 2016 - Fluctuations in Electronic Energy Affecting Singlet Fission Dynamics and Mixing ... Citation data is made available by participants in CrossRef's ... Fluctuations in Electronic Energy Affecting Singlet Fission Dynamics ... pubs.acs.org/doi/pdf/10.1021/acs.jpclett.5b02678 by Y Fujihashi - 2016 - Cited by 5 - Related articles Jan 6, 2016 - Therefore, the fluctuations in the electronic energies could be correlated, and ... Redfield theory;36 however, the fission dynamics obtained by. Fluctuations in Electronic Energy Affecting Singlet Fission Dynamics ... pubs.acs.org/doi/full/10.1021/acs.jpclett.5b02678 by Y Fujihashi - 2016 - Cited by 5 - Related articles Jan 6, 2016 - Fluctuations in Electronic Energy Affecting Singlet Fission Dynamics and ...... R. H.Exciton Fission and Charge Generation via Triplet Excitons in ... Multiplying Systems for Fission Energy bostoncommons.net › Energy Oct 8, 2016 - [1] The formalism accounts for the fact that the fission energy ? ? is also a random variable, thus the fluctuations of the total energy generated ... Starscape: The Silver Bullet - Page 176 - Google Books Result https://books.google.com/books?isbn=1469716380 Brad Aiken - 2000 - Fiction The first was the sheer size of the field that we'd have to generate to protect an ... the same problem—a fluctuation in the energy signature yielded by the fission. Microscopic phase-space exploration modeling of $^{258} $ Fm ... https://arxiv.org/pdf/1609.01424 by Y Tanimura - 2016 - Cited by 4 - Related articles Sep 6, 2016 - phase-space exploration leading to larger fluctuations in collective space. The total kinetic energy ... as pre- and post-scission particle emission, are obtained. ... of fission and by its importance in nuclear energy pro- duction ...
