• Journal of the Korean Society of Safety
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• v.33 no.1
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• pp.35-40
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• 2018

This research aimed to develop an leakage detector of analyzing the electric potential generated from the electric leakage of electric equipment of the fountain. To accomplish this goal, the potential gradient was analyzed against path 1 ~ path 4; this was done by taking the lighting of a fountain as the electric leakage point based on code analyses in Korea and other countries. Lighting 1 was taken as the electric leakage point, and the earthing point was set against lightings(2~3). It appeared that the allowable touch voltage against the 1 type(under 2.5 V) exceeded 60.0%. Therefore, the lighting of fountain turned out to be the most dangerous point, and electric shock could be formed by the electric leakage of electric equipment in underwater as well as by the lighting. An leakage detector was developed based on this risk; this detector is capable of analyzing the electric potential of a electric equipments of the fountain in underwater. Then, a verification test was carried out. This leakage detector can be used to measure electric potential in various submerged areas such as swimming pools, flooded spaces, and fountains.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.783-788
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• 2005

Detection of small leakage current is the most important technique in arrester diagnosis. Various types of leakage current detector have been commercialized, but they are not available for the railway arresters including voltage harmonics, and do not furnish enough information needed for arrester diagnosis. This paper describes the development of a leakage current detector which is suitable for the railway arresters. The detector is consisted of a sensor unit with amplifier, an optical linker and main analyzer. Frequency bandwidth and measuring range of the detector is 9[Hz]$\~$850[Hz] and 50[uA]$\~$5[mA], respectively.

• Journal of Radiation Protection and Research
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• v.43 no.4
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• pp.154-159
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• 2018

Background: To prevent small leakage accidents, a real-time and direct detection system for small leaks with a detection limit below that of existing systems, e.g. $0.5gpm{\cdot}hr^{-1}$, is required. In this study, a small-size beta detector, which can be installed inside the reactor containment (CT) building and detect small leaks directly, was suggested and its feasibility was evaluated using MCNPX simulation. Materials and Methods: A target nuclide was selected through analysis of radiation from radionuclides in the reactor coolant system (RCS) and the spectrum was obtained via a silicon detector simulated in MCNPX. A window was designed to reduce the background signal caused by other nuclides. The sensitivity of the detector was also estimated, and its shielding designed for installation inside the reactor CT. Results and Discussion: The beta and gamma spectrum of the silicon detector showed a negligible gamma signal but it also contained an undesired peak at 0.22 MeV due to other nuclides, not the $^{16}N$ target nuclide. Window to remove the peak was derived as 0.4 mm for beryllium. The sensitivity of silicon beta detector with a beryllium window of 1.7 mm thickness was derived as $5.172{\times}10^{-6}{\mu}Ci{\cdot}cc^{-1}$. In addition, the specification of the shielding was evaluated through simulations, and the results showed that the integrity of the silicon detector can be maintained with lead shielding of 3 cm (<15 kg). This is a very small amount compared to the specifications of the lead shielding (600 kg) required for installation of $^{16}N$ gamma detector in inside reactor CT, it was determined that beta detector would have a distinct advantage in terms of miniaturization. Conclusion: The feasibility of the beta detector was evaluated for installation inside the reactor CT to detect small leaks below $0.5gpm{\cdot}hr^{-1}$. In future, the design will be optimized on specific data.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2748-2754
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• 2022

Because existing reactant coolant system (RCS) leakage detection mechanisms are insensitive to small leaks, a real-time, direct detection system with a detection threshold below 0.5 gpm·hr^-1 was studied. A beta-ray detection system using a silicon detector with good energy resolution for beta rays and a low gamma-ray response was proposed. The detection performance in the leakage condition was evaluated through experiments and simulations. The concentration of ¹⁶N in the coolant corresponding to a coolant leakage of 0.5 gpm was calculated using the analytic method and ORIGEN-ARP. Based on the concentration of ¹⁶N and the measurement of the silicon detector with ⁹⁰Sr/⁹⁰Y, the beta-ray count rate was estimated using MCNPX. To evaluate the effect of gamma rays inside the containment building, the signal-to-noise ratio (SNR) was calculated. To evaluate the count rate ratio, the radiation field inside the containment building was simulated using MCNPX, and response evaluation experiments were performed using beta and gamma rays on the silicon detector. The expected beta-ray count rate at 0.5 gpm leakage was 7.26 × 10⁵ counts/sec, and the signal-to-background count rate ratio exceeded 88 for a transport time of 10 s, demonstrating its suitability for operation inside a reactor containment building.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.74-76
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• 1995

In this paper, the results of development of arrester leakage current detector using micro computer are described. This detector is based on harmonic analysis of the leakage current by FFT. The change of leakage current is the recognized measure of deterioration. For low sensitivity to disturbance, this device used optical fiber. This will be a great benefit of detecting deterioration ZnO arrester.

• Journal of the Korea Safety Management & Science
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• v.17 no.4
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• pp.297-304
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• 2015

This study concerns the integrated gas sensor system of wire and wireless communication by using IoT(Internet of Things) technology. First, communication part is that it delivers the detection information, which transferred by wire or wireless communication and required control procedure based on a wireless module that receives the gas leakage information from wired or wireless detector, to administrator or user's terminal. Second, receiver part is that it shows the location and information, which received from the wired detector formed by a detecting sensor's node as linking with the communication part, and transfers these to the communication part. Third, wireless detector formed as a communication module of a detecting sensor node is that it detects gas leakage and transfers the information through wireless as a packet.Fourth, wired detector communicated with the receiver part and formed as a communication module of a detecting sensor node is that it detects gas leakage, transfers and shows the information as a packet. Fifth, administrator's terminal is that it receives gas leakage information by the communication part, transfers the signal by remote-control, and shut off a gas valve as responding the information. Sixth, database is that it is connected with the communication part; it sets and stores the default values for detecting smoke, CO., and temperature; it transfers this information to the communication part or sends a gas detecting signal to user's terminal. Seventh, user's terminal is that it receives each location's default value which stored and set at the database; it manages emergency situation as shutting off a gas valve through remote control by corresponding each location's gas leakage information, which transferred from the detector to the communication part by wireless.It is possible to process a high quality data regarding flammable or toxic gas by transferring the data, which measured by a sensor module of detector, to the communication part through wire and wireless. And, it allows a user to find the location by a smart phone where gas leaks. Eventually, it minimizes human life or property loss by having stability on gas leakage as well as corresponding each location's information quickly.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.631-633
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• 1995

In this paper, the results of development of arrester leakage current detector using micro computer are described. This detector is based on harmonic analysis of the leakage current by FFT. For low sensitivity to disturbance, this device used optical fiber. This will be a great benefit of detecting deterioration ZnO arrester.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.11
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• pp.572-576
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• 2004

Various devices for diagnosing arrester soundness are suggested, and most of them simply measure magnitude of leakage current. However, such kind of devices do not provide detailed information needed for the diagnosis. In this study, we designed and fabricated a new arrester analyzer by means of measuring the magnitude, the phase vs. wave height and the harmonics of total leakage currents. The analyzer is composed of a current detector, an optical linker, and a main device operated by a microprocessor. The main device is connected with leakage current detector optically not to be influenced by electromagnetic interference. The analyzer developed measures only total leakage currents, but analyzes most parameters needed for the arrester diagnostics.

• Journal of Radiation Protection and Research
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• v.43 no.4
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• pp.131-136
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• 2018

Background: We investigated the current characteristics of a thin-film Ag electrode on a chemical vapor deposition (CVD) diamond. The CVD diamond is widely recognized as a radiation detection material because of its high tolerance against high radiation, stable response to various dose rates, and good sensitivity. Additionally, thin-film Ag has been widely used as an electrode with high electrical conductivity. Materials and Methods: Considering these properties, the thin-film Ag electrode was deposited onto CVD diamonds with varied deposition thicknesses (${\fallingdotseq}50/98/152/257nm$); subsequently, the surface thickness, surface roughness, leakage current, and photo-current were characterized. Results and Discussion: The leakage current was found to be very low, and the photo-current output signal was observed as stable for a deposited film thickness of 98 nm; at this thickness, a uniform and constant surface roughness of the deposited thin-film Ag electrode were obtained. Conclusion: We found that a CVD diamond radiation detector with a thin-film Ag electrode deposition thickness close to 100 nm exhibited minimal leakage current and yielded a highly stable output signal.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05b
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• pp.39-42
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• 2002

There is a renewed interest in the application of photoconductors especially Cd(Zn)Te to x-ray imaging. In this paper, We investigate effects on x-ray detection characteristic of Zn dopped CdTe detector. Cd(Zn)Te film was fabricated by vacuum thermal evaporation method and then investigate physical analysis using EPMA and XRD. We investigated the leakage current and X-ray photosensitivity as applied voltage about fabricated Cd(Zn)Te film. Experimental results showed that the increase of Zn dopped concentration in $Cd_{1-x}Zn_{x}Te$ detector reduced a leakage current and improved a signal to noise ratio significantly.