• Nuclear Engineering and Technology
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• 제56권5호
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• pp.1725-1732
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• 2024

In nuclear power plants, reactor coolant leakage can occur due to various reasons. Early detection of leaks is crucial for maintaining the safety of nuclear power plants. Currently, a detection system is being developed in Korea to identify reactor coolant system (RCS) leakage of less than 0.5 gpm. Typically, RCS leaks are detected by monitoring temperature, humidity, and radioactivity in the containment, and a water level in the sump. However, detecting small leaks proves challenging because the resulting changes in the containment humidity and temperature, and the sump water level are minimal. To address these issues and improve leak detection speed, it is necessary to quantify the leaks and develop an artificial intelligence-based leak detection system. In this study, we employed bidirectional long short-term memory, which are types of neural networks used in artificial intelligence, to predict the relative humidity in the leakage area for leak quantification. Additionally, an optimization technique was implemented to reduce learning time and enhance prediction performance. Through evaluation of the developed artificial intelligence model's prediction accuracy, we expect it to be valuable for future leak detection systems by accurately predicting the relative humidity in a leakage area.

• 한국안전학회지
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• 제34권6호
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• pp.13-21
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• 2019

Leakage accidents in businesses dealing with hazardous chemicals can have a great impact on the workers inside the workplace, as well as residents outside the workplace. In fact, there were cases where hazardous chemicals leaked from many businesses. As a result, the Chemicals Control Act(CCA) was enacted in 2015, the Ministry of Environment introduced an Off-site Risk Assessment(ORA). The purpose of the ORA is to secure safety from the installation of the design of the workplace facilities so that chemical accidents of hazardous chemical handling facilities do not cause human or physical damage outside the workplace. In general, the ORA qualitatively determines where a protected facility is within the scope of the accident scenario. However, elderly who belong to the sensitive group is more sensitive than the general group under the same chemical accident effect, and the extent of the damage is serious. According to data from the Korea National Statistic Office, the number of elderly people is expected to increase steadily. Therefore, a quantitative risk analysis considering the elderly is necessary as a result of a chemical accident. In this study, accident scenarios for 14 locations were set up to perform emergency evacuation due to toxic gas leakage of Cl₂(Chlorine) and HF(Hydrogen Fluoride), and the effects of exposure were analyzed based on the evacuation velocity difference of age 20s and 60s. The ALOHA(Areal Locations of Hazardous Atmospheres) program was used to calculate the concentration for assessing the effects. The time of exposure to toxic gas was calculated based on the time it took for the evacuation to run from the start point to the desired point and a methodology was devised that could be applied to the risk calculation. As a result of the study, the relative risk of the elderly, the sensitive group, needs to be determined.

• 조명전기설비학회논문지
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• 제23권10호
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• pp.81-89
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• 2009

본 논문에서는 일반용 전기설비 중에서 전기안전관리의 사각지대로 분류되는 보안등 전기설비를 대상으로 전기 안전요소들을 계측하고 원격 모니터링할 수 있는 보안등 원격점검시스템을 개발하였다. 단말기에서 계측하는 누설 전류는 위상차 측정법을 이용한 저항성분 누설전류($I_{gr}$) 측정 알고리즘을 이용하였으며, 계측데이터 전송을 위한 중 계기와 MMI에서 모니터링할 수 있는 시스템을 제작하였으며, 저항성 누설전류($I_{gr}$)검출 알고리즘의 타당성을 확인하기 위해 실험실 기반의 성능시험으로 저항성 누설전류($I_{gr}$)를 측정하였다.

• 한국위험물학회지
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• 제6권2호
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• pp.7-12
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• 2018

Hydrochloric acid is a highly corrosive toxic substance and requires proper safety to minimize damage in case of leakage. Among the various risk-reduction facilities, the dike is a typical safety facility installed to protect the surrounding buildings and facilities by preventing the external spread of hazardous materials from the storage tank. In this study, the KORA program was used to assume leakage accident of hydrochloric acid storage tank. At this time, the extent of the damage effects of ERPG-2 were assessed for each of the three separation distance between the storage tank and the dike. The study found that the smaller the separation distance between the dike and the storage tank, the smaller the extent of damage caused by hydrochloric acid leakage, and the greater the impact of indoor conditions under the same conditions. Through this process, we are going to assist in selecting locations and installing facilities for new and existing businesses.

• 센서학회지
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• 제24권5호
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• pp.306-310
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• 2015

IoT(Internet of Things) based underground risk assessment system surrounding water pipeline enables an advanced monitoring and prediction for unexpected underground hazards such as abrupt road-side subsidence and urban sinkholes due to a leak in water pipeline. For the development of successful assessment technology, the PSU(Water Pipeline Safety Unit) which detects the leakage and movement of water pipes. Then, the IoT-based underground risk assessment system surrounding water pipeline will be proposed. The system consists of early detection tools for underground events and correspondence services, by analyzing leakage and movement data collected from PSU. These methods must be continuous and reliable, and cover certain block area ranging a few kilometers, for properly applying to regional water supply changes.

• 한국전기전자재료학회논문지
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• 제29권10호
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• pp.595-600
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• 2016

In this paper, the oxide currents of thin silicon oxides is investigated. The oxide currents associated with the on time of applied voltage were used to measure the distribution of voltage stress induced traps in thin silicon oxide films. The stress induced leakage currents were due to the charging and discharging of traps generated by stress voltage in the silicon oxides. The stress induced leakage current will affect data retention in memory devices. The oxide current for the thickness dependence of stress current and stress induced leakage currents has been measured in oxides with thicknesses between $109{\AA}$, $190{\AA}$, $387{\AA}$, and $818{\AA}$ which have the gate area $10^{-3}cm^2$. The oxide currents will affect data retention and the stress current, stress induced leakage current is used to estimate to fundamental limitations on oxide thicknesses.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.260-263
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• 2006

The number of empty houses during normal working hours is rising. As a result, the number of uninspected electric installations for general use is increasing. To define the potential risk of the electric installation, measurement of leakage current has been getting considered but because the measured leakage current value also contained leakage current by capacitance, the measured value can not be adapted to absolute reference to the installation. Therefore in this paper, the correlation between the condition of electric installation and leakage current were analyzed.

• 한국기계가공학회지
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• 제10권3호
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• pp.28-32
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• 2011

The safety of transporting equipment in a cryogenic condition is one of important problems under the circumstances that the application weight of natural gas is gradually increasing. As a larger disaster may be generated by leakage of oil or gas from valves in case of fire occurrence of a ship, the present research applied a numerical analysis method on thermal stress distribution and deformation, etc. to the design of ball valves satisfying fire safety test's specification(API607) to prevent this. In addition, the present research progressed fire safety tests and compared the test result with numerical analysis results. The Max stress by parts was confirmed through thermal analysis of major parts to evaluate safety. The fire safety test was progressed according to the regulation of API607.

• 한국가스학회:학술대회논문집
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• 한국가스학회 2000년도 추계학술발표회 논문집
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• pp.87-94
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• 2000

• Journal of Power Electronics
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• 제15권1호
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• pp.256-267
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• 2015

Grid-connected transformerless photovoltaic (PV) inverters (TPVIs) are increasingly dominating the market due to their higher efficiency, lower cost, lighter weight, and reduced size when compared to their transformer based counterparts. However, due to the lack of galvanic isolation in the low voltage grid interconnections of these inverters, the PV systems become vulnerable to leakage currents flowing through the grounded star point of the distribution transformer, the earth, and the distributed parasitic capacitance of the PV modules. These leakage currents are prohibitive, since they constitute an issue for safety, reliability, protection coordination, electromagnetic compatibility, and module lifetime. This paper investigates a wide range of multi-kW range power rating TPVI topologies and classifies them in terms of their leakage current attributes. This systematic classification places most topologies under a small number of classes with basic leakage current attributes. Thus, understanding and evaluating these topologies becomes an easy task. In addition, based on these observations, new topologies with reduced leakage current characteristics are proposed in this paper. Furthermore, the important efficiency and cost determining characteristics of converters are studied to allow design engineers to include cost and efficiency as deciding factors in selecting a converter topology for PV applications.