The interpretation of kinetic experiments for source-driven systems is often based on the relationship between the prompt time response and the multiplicativity of the system. The presence of a reflector may modify the physical features of such response. For systems in which the neutron histories are dominated by the presence of the reflector, it becomes difficult to determine the subcriticality value through the observation of the flux response. In this work the characteristics of this phenomenon are analysed, starting from a simple diffusion model that allows to easily get a physical insight. The modification of the time constant is interpreted in terms of modifications to the effective mean prompt neutron generation time, which is increased by the presence of the reflector. Afterwards, more realistic evaluations are carried out by using Monte Carlo simulations of pulsed experiments in source-driven systems. The results confirm the conclusions that may be drawn from the analysis of the simple cases. Copyright © (2015) by the American Nuclear Society All rights reserved.

Reflector effects on the kinetic response in subcritical systems

Carta M.
2015

Abstract

The interpretation of kinetic experiments for source-driven systems is often based on the relationship between the prompt time response and the multiplicativity of the system. The presence of a reflector may modify the physical features of such response. For systems in which the neutron histories are dominated by the presence of the reflector, it becomes difficult to determine the subcriticality value through the observation of the flux response. In this work the characteristics of this phenomenon are analysed, starting from a simple diffusion model that allows to easily get a physical insight. The modification of the time constant is interpreted in terms of modifications to the effective mean prompt neutron generation time, which is increased by the presence of the reflector. Afterwards, more realistic evaluations are carried out by using Monte Carlo simulations of pulsed experiments in source-driven systems. The results confirm the conclusions that may be drawn from the analysis of the simple cases. Copyright © (2015) by the American Nuclear Society All rights reserved.
9781510808041
Neutron kinetics;Reflected reactors;Subcritical systems;Pulsed experiments;Monte Carlo analyses
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.12079/5884
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