Acoustic Leak Detection Technology for Water/Steam Small Leaks and Microleaks into Sodium to Protect an SFR Steam Generator

Kim, Tae Joon; Yugay, Valeriy S.; Jeong, Ji-Young; Kim, Jong-Man; Kim, Byeung-Ho; Lee, Tae‐Ho; Lee, Yongbum; Kim, Yeong-Il; Hahn, Dohee

doi:10.13182/nt10-a9489

Cited by 16 publications

(17 citation statements)

References 4 publications

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“…However, here we work at quite a low sampling rate and it can be assumed that using higher sampling rate and the possibility of finding characteristic spectral content at significantly higher frequencies (Kim et al, 2010) will allow this time to decrease. For a sodium-nitrogen energy conversion system, which might be a possibility for the ASTRID reactor, decision times up to one minute for nitrogen into sodium leak detection are assumed to be satisfactory (Perrin, 2014).…”

Section: Discussionmentioning

confidence: 99%

“…One may note that taking the ratio will give rapidly increasing weight to spectral regions where background noise is decreasing, without any regard to whether the leak noise spectrum has significant content in this region or not. Also, neural network methods such as the one used in Kim et al (2010) have been popular in the literature. This approach however requires a substantial training database of labeled sounds.…”

Section: Introductionmentioning

confidence: 99%

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Application of a new passive acoustic leak detection approach to recordings from the Dounreay prototype fast reactor

Marklund

Michel

2015

Annals of Nuclear Energy

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Application of a new passive acoustic leak detection approach to recordings from the Dounreay prototype fast reactor

Marklund

Michel

2015

Annals of Nuclear Energy

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“…These acoustic phenomenon remains complex to be modelled numerically. Kim et al characterized the noise generated by different leak flow rates experimentally and showed that for a very small leak, the water and the sodium reacts so quickly that the acoustic source stays localized at the crack position [4]. In the present paper, one considers only the acoustic source due to bubbles oscillations appearing during a very small leak.…”

Section: -Introductionmentioning

confidence: 97%

“…Different studies focussing on active and passive detection techniques have been published in the past [1][2][3]. The paper written by Kim et al [4] focusses on characterising the acoustic noise spectra of different water-into-sodium leaks for a small flow rates (<1 g H2O /s). Chikazawa [5] developed a beamforming method to detect a leak at a frequency of 10 kHz assuming that it emits a planar acoustic field.…”

Section: -Introductionmentioning

confidence: 99%

Use of beamforming for detecting an acoustic source inside a cylindrical shell filled with a heavy fluid

Moriot

Maxit

Guyader

et al. 2015

Mechanical Systems and Signal Processing

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The acoustic detection of defects or leaks inside a cylindrical shell containing a fluid is of prime importance in the industry, particularly in the nuclear field. This paper examines the beamforming technique which is used to detect and locate the presence of an acoustic monopole inside a cylindrical elastic shell by measuring the external shell vibrations. In order to study the effect of fluid-structure interactions and the distance of the source from the array of sensors, a vibro-acoustic model of the fluid-loaded shell is first considered for numerical experiments. The beamforming technique is then applied to radial velocities of the shell calculated with the model. Different parameters such as the distance between sensors, the radial position of the source, the damping loss factor of the shell, or of the fluid, and modifications of fluid properties can be considered without difficulty. Analysis of these different results highlight how the behaviour of the fluid-loaded shell influences the detection. PFinally, a test in a water-filled steel pipe is achieved for confirming experimentally the interest of the presented approach. -IntroductionThe fast and reliable detection of acoustic sources in complex industrial cylinder systems is of capital interest since such sources can be the consequence of defects or leaks in the installation. In the nuclear field, for example, a leak in a Steam Generator Unit (SGU) of a sodium fast nuclear reactor induces a water-sodium reaction. This reaction can damage the component. The purpose of this paper is to study the possibility of using a passive vibroacoustic method to detect and locate the noise generated by a water-sodium reaction of leak rate inferior to 1 g H2O /s. Different studies focussing on active and passive detection techniques have been published in the past [1][2][3]. The paper written by Kim et al. [4] focusses on characterising the acoustic noise spectra of different water-into-sodium leaks for a small flow rates (<1 g H2O /s). Chikazawa [5] developed a beamforming method to detect a leak at a frequency of 10 kHz assuming that it emits a planar acoustic field. This assumption, which is reasonable in the high frequency domain, necessitates a high number of sensors to cover the whole steam generator. Sing and Rao [6] looked at detecting a water injection into liquid sodium by measuring the acoustic field radiated by the installation with microphones located far from the system. Such a method is very simple but may be easily disturbed by external acoustic sources. Moreover, it may be useful for detecting leaks of flow rate strong enough to come out of the background noise. In the 1980's, Greene et. al developed a beamforming passive vibro-acoustic method called GAAD to detect and locate a sodium-water reaction in a SGU of a sodium-cooled fast nuclear reactor [7][8][9]. In these papers, authors characterized with an experiment the performance of the localization and the detection time against the leak rate and the SGU power level. These papers show that ...

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“…More specifically, different studies focussing on active and passive leak detection techniques in SFR SGU have been published in the past [8][9][10]. The paper by Kim et al [11] focussed on characterising the acoustic noise spectra of different water-into-sodium leaks for a small leak flow (<1g/s). Chikazawa [12] applied a beamforming method to detect a leak at a frequency of 10 kHz in a SGU assuming that it emits a planar acoustic field.…”

Section: Introductionmentioning

confidence: 99%

Experimental results of passive vibro-acoustic leak detection in SFR steam generator mock-up

Moriot¹,

Maxit²,

Guyader³

et al. 2013

2013 3rd International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and Their Applications (ANIMM

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International audience# N° 1121 Experimental results of passive vibro-acoustic leak detection in SFR steam generator mock-up 1 Abstract— Regarding to GEN 4 context, it is necessary to fulfil the high safety standards for sodium fast reactors (SFR), particularly against water-sodium reaction which may occur in the steam generator units (SGU) in case of leak. This reaction can cause severe damages in the component in a short time. Detecting such a leak by visual in-sodium inspection is impossible because of sodium opacity. Hydrogen detection is then used but the time response of this method can be high in certain operating conditions. Active and passive acoustic leak detection methods were studied before SUPERPHENIX plant shutdown in 1997 to detect a water-into-sodium leak with a short time response. In the context of the new R&D studies for SFR, an innovative passive vibro-acoustic method is developed in the framework of a Ph.D. thesis to match with GEN 4 safety requirements. The method consists in assuming that a small leak emits spherical acoustic waves in a broadband frequency domain, which propagate in the liquid sodium and excite the SGU cylindrical shell. These spatially coherent waves are supposed to be buried by a spatially incoherent background noise. The radial velocities of the shell is measured by an array of accelerometers positioned on the external envelop of the SGU and a beamforming treatment is applied to increase the signal-to-noise ratio (SNR) and to detect and localize the acoustic source. Previous numerical experiments were achieved and promising results were obtained. In this paper, experimental results of the proposed passive vibro-acoustic leak detection are presented. The experiment consists in a cylindrical water-filled steel pipe representing a model of SGU shell without tube bundle. A hydrophone emitting an acoustic signal is used to simulate an acoustic monopole. Spatially uncorrelated noise or water-flow induced shell vibrations are considered as the background noise. The beamforming method is applied to vibration signals measured by a linear array of accelerometers on the shell. Satisfying results are obtained regarding to detection and localization of the source smothered by the background noise. This research was carried in the framework of the LabEx CeLyA ("Centre Lyonnais d'Acoustique", ANR-10-LABX-60) by the LVA/ INSA de Lyon, in collaboration with AREVA and the CEA (Commissariat à l'Energie Atomique et aux Energies Alternatives) within the framework of a co-financing partnership. The authors are grateful for the interest and financial support received from these two entities. J. Moriot and O. Gastaldi are with DEN/STPA

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Acoustic Leak Detection Technology for Water/Steam Small Leaks and Microleaks into Sodium to Protect an SFR Steam Generator

Cited by 16 publications

References 4 publications

Application of a new passive acoustic leak detection approach to recordings from the Dounreay prototype fast reactor

Application of a new passive acoustic leak detection approach to recordings from the Dounreay prototype fast reactor

Use of beamforming for detecting an acoustic source inside a cylindrical shell filled with a heavy fluid

Experimental results of passive vibro-acoustic leak detection in SFR steam generator mock-up

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