Theory of Pulsed Neutron Experiments in Multiplying Media
| Autor: | T. J. Krieger, P. F. Zweifel |
|---|---|
| Rok vydání: | 1959 |
| Předmět: |
Physics
010308 nuclear & particles physics Differential equation Astrophysics::High Energy Astrophysical Phenomena 0211 other engineering and technologies Time constant 02 engineering and technology Thermal diffusivity 01 natural sciences Neutron temperature Computational physics Nuclear Energy and Engineering 0103 physical sciences Neutron source Neutron 021108 energy Exponential decay Atomic physics Geometric and material buckling |
| Zdroj: | Nuclear Science and Engineering. 5:21-27 |
| ISSN: | 1943-748X 0029-5639 |
| DOI: | 10.13182/nse59-a27324 |
| Popis: | The spatial and temporal distribution of thermal neutrons in a multiplying assembly following the introduction of a short burst of fast neutrons is investigated by means of an extension of the so-called “asymptotic reactor theory” to the time-dependent case. It is shown that the solution for an nth mode fast neutron source can be reduced to that for an nth mode thermal neutron source, so that only the latter need be considered. A formal solution to the time-dependent thermal diffusion equation with an nth mode thermal source is found for an arbitrary slowing-down kernel. The asymptotic behavior of the flux in the long-time limit is shown to be exponential, with a decay constant satisfying a generalized material buckling equation. The asymptotic behavior following a burst of fast neutrons is also found to be exponential with the same time constant. In a continuous slowing-down model, all neutrons slow down in the same time, implying that the time-dependent part of the time-dependent slowing-down ke... |
| Databáze: | OpenAIRE |
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