Experimental study of current formation in direct-charge detectors with a rhodium emitter

Mitin, V. I.; Shikalov, V. F.; Tsimbalov, S. A.

doi:10.1007/bf02116038

Cited by 5 publications

(3 citation statements)

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“…Calculations and experiments have confirmed that such sensors make it possible to detect neutron flux fluctuations in a wide frequency range due to the instantaneous component of the current [2] that is due to the Compton effect. The instantaneous component of the current is proportional to the main (activation) component of the sensor current.…”

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confidence: 78%

Analysis of neutron flux noise due to coolant parameter fluctuations in a VVÉR core

et al. 2007

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The results of investigations of noise appearing in the signals from direct-charge sensors of the in-reactor monitoring system of VVÉR reactors as a result of coolant parameter fluctuations are presented. The calculations and experimental data are used to analyze the dependence of the amplitude of the neutron flux oscillations (local intensity) at the locations of sensors as a function of the magnitude and frequency of the fluctuations of a specific coolant parameter. The NOSTRA program was used to perform the calculations. The results of the analysis were used in the in-reactor noise diagnostics system in the No. 3 unit of the Kalinin and the No. 1 unit of the Tianwan (China) nuclear power plants.In-reactor noise diagnostics has been developed on the basis of an analysis of the noise in various parameters of the core of a nuclear reactor. Analysis of neutron flux noise is one direction of noise diagnostics whose main goals are detection and localization of coolant boiling sites inside a reactor core. Monitoring the moment when coolant begins to boil makes it possible to refine the real conditions for removing heat in the core and to determine the design limits more accurately. The computational and experimental works described in the present article were performed to solve the problem of instrumentation monitoring of coolant boiling.The standard in-reactor monitoring sensors distributed over a core are direct-charge sensors with a rhodium emitter [1]. Calculations and experiments have confirmed that such sensors make it possible to detect neutron flux fluctuations in a wide frequency range due to the instantaneous component of the current [2] that is due to the Compton effect. The instantaneous component of the current is proportional to the main (activation) component of the sensor current. For the same coolant density fluctuations, the amplitude of the sensor current fluctuations is proportional to the neutron flux or the main component of the sensor current. The standard deviation of the variable component of the sensor current reduced to its average main current -the dimensionless parameter ∆ -was chosen as the parameter characterizing the state of the coolant.The neutron flux fluctuations depend on the coolant density fluctuations, which influence the change in the moderating properties of the coolant and arise as a result of fluctuations of the temperature, flow rate, and pressure of the coolant in the reactor. When steam starts to form, the nonlinearity of the dependence of the coolant density on the amplitude of the fluctuations of the coolant parameters at the entrance into a fuel assembly becomes stronger. As a result, the amplitude of the coolant density fluctuations increases, which increases the amplitude of the neutron flux noise in the region of boiling.Experimental Results. The experiments confirmed that rhodium sensors make it possible to detect the moment local boiling of the coolant appears and starts to develop. The possibility of detecting boiling onset was shown in experi-

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confidence: 78%

Analysis of neutron flux noise due to coolant parameter fluctuations in a VVÉR core

et al. 2007

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“…These SPNDs have a high sensitivity to neutrons, they also have excellent signal linearity, and their production technology is well developed. And yet, on the background of existing trends in increasing the radiation dose and operating temperature of the used in the core materials, the signal delay of the activation SPNDs and their relatively short service life [7][8][9][10] put the question: is it enough to use only inertial detectors from the point of the safety view?…”

Section: Introductionmentioning

confidence: 99%

The Compton Neutron Hafnium Detector: Electric Charge Generation Rate

Azhazha¹,

Bogdan²,

Gann³

et al. 2022

Problems of Atomic Science and Technology

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The properties of a Compton neutron detector with the emitter of metallic Hf were studying in this work. Using the previously calculated the emitter material nuclide composition during reactor irradiation, the dependence of the emitter signal value on the irradiation time was obtained with a step of 1 year for 5 years. It is shown that the composition modification due to nuclear transmutations changes the rate of an electric charge generation in the emitter.

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“…2) for reasons of safety, when increasing the core energy release irregularity ratio, it is necessary that the neutron field monitoring is carried out by the detector with a minimum response time, but the rhodium SPND (like any other activation detector) does not fit this requirement [1,10,11,20,29]. Consequently, it is necessary to create a detector, whose, characteristics (operation life, response time, etc.)…”

Section: Introductionmentioning

confidence: 99%

Compton-emissive hafnium detector of neutrons for in-core monitoring

Ulybkin¹,

Rybka²,

Kovtun³

et al. 2018

Nucl. Phys. At. Energy

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The work is devoted to substantiating the use of metallic hafnium as the emitter of the Compton (prompt-response) in-core detector of thermal and resonant neutrons. The main trends in the development of nuclear power engineering, which raise the interest in the use of hafnium, are considered. The known data on the behavior of both Compton and βemission self-powered neutron detectors (SPND) are generalized. The Compton SPND signal formation mechanism for the case of the irradiation by reactor-type fluxes of neutrons and gamma quanta is considered. The paper presents the calculation result of the hafnium burning-out degree for the conditions of WWER and RBMK reactors. The influence of the gamma radiation "sources", which provide the largest contribution to the electrons production in the detector is considered.

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Experimental study of current formation in direct-charge detectors with a rhodium emitter

Cited by 5 publications

References 1 publication

Analysis of neutron flux noise due to coolant parameter fluctuations in a VVÉR core

Analysis of neutron flux noise due to coolant parameter fluctuations in a VVÉR core

The Compton Neutron Hafnium Detector: Electric Charge Generation Rate

Compton-emissive hafnium detector of neutrons for in-core monitoring

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