Abstract
The safety improvement of nuclear reactors requires continuous efforts in understanding the fundamental physical quantities related to the fission process. In neutronic models, the reactor dynamics is covered by the kinetic parameters to characterize the temporal behavior of the neutron population subject to perturbations. The reactor transfer function is a frequency domain analogy of this temporal description. It can be measured experimentally through transfer function analysis via noise analysis or kinetic modulation, for the study of reactor stability and kinetic parameters. This paper summarizes the experimental measurements of reactor transfer function through kinetic modulation. Extensive work have been conducted experimentally, starting from the beginning of reactor physics research. An overview is given regarding various experimental designs and conducted analyses. The concepts of the modulation system are also discussed. The current work is limited to online contents and internal archives of CEA Cadarache due to difficulties in accessing references traced back to 1950s.
Highlights
The understanding of reactor dynamics, which are governed by the behavior of the in-core neutron population, is crucial for the operation and safety analysis of nuclear reactors
When a reactor is close to criticality, the socalled reactivity and kinetic parameters can be defined as integral properties of the entire core to describe the temporal evolution of the neutron population, referred to as the point kinetics (PK) approximation derived from the neutron transport equation [1]
Inspired by control system engineering, a comprehensive understanding of reactor system stability was developed within the PK framework, known as the reactor transfer function (RTF) analysis [2]
Summary
The understanding of reactor dynamics, which are governed by the behavior of the in-core neutron population, is crucial for the operation and safety analysis of nuclear reactors. The practical measurement of this transfer function in the reactor core relies on Fourier analysis using either neutron noise methods or modulation methods. The measured RTF yields information about the kinetic parameters and the modulation magnitude, as will be shown . By assuming the former as known the reactivity worth of samples is measured. Instrumentation and safety studies service (SPESI) of CEA Cadarache, a new modulation device is currently under development. We intend to summarize the experimental work conducted in determining the RTF of low power reactors and designing the associated modulators, for studies ranging from the 1950s to 2020.
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