• Fire Science and Engineering
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• v.33 no.6
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• pp.105-113
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• 2019

This study investigates the toxicity characteristics of two Non-Class 1E Cables (For security reasons, we refer to company A and company B) used in nuclear power plants according to the accelerated deterioration period. In accordance with NES 713 test equipment and standards, tests were carried out on non-aged cables and the cables subjected to 20- and 40-year-accelerated-deterioration; each of the cables was further classified into sheath and insulation. The test results showed that the toxicity indices of 20- and 40-year-accelerated-aged cables were higher than those for the non-aged cables, and 20-year-aged cables of both A and B companies showed the highest toxicity indices. This is attributed to the extensive emissions of carbon monoxide and halide gases such as hydrogen chloride and hydrogen bromide. Furthermore, to analyze the toxicity indices of sheath and insulation in detail, the US Department of Defense standard (MIL-DTL) was applied to determine whether the Toxicity index (T.I.) allowance was exceeded, and the results showed that the insulating materials emitted considerably more than the allowable limit.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.139-146
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• 2008

Conductors in overhead transmission lines are exposed under various environmental conditions for a long period of time, so that they may be slowly degraded due to air pollutant or thermal history. Aged conductors may reduce power system reliability and public safety. Therefore, diagnosis of aged conductors in service becomes more important concerns with respect to keeping power delivery stable with a proper capability, replacing aged conductors, or constructing a new line. In this paper, we posed a new method to diagnose the refurbishment life and estimate the remaining life of aged conductors by measuring dips. As analyzing some relations of conductor temperature, conductor current, and tension load, it could be verified that dip exactly shows mechanical tension loss for aged conductor. Based on several simulation results, it was shown that the proposed method may be effectively used to diagnose the refurbishment life or remaining one of overhead conductors.

• Nuclear industry
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• v.5 no.2 s.24
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• pp.45-49
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• 1985

원자력발전소는 다중방호의 개념에서 복수의 안전설비를 갖는 등 계통이 팽대하고 복잡하며 또한 엄격한 품질관리를 실시하므로 다른 발전형식에 비해 건설비가 높은 편이다. 따라서 설비의 유효이용을 도모하는 것이 중요하다. 이와 같은 관점에서 앞으로 기설발전소의 장수명화를 도모하고, 전수명기간의 발전전력량을 증대시킴으로서 원자력발전 코스트를 다른 발전코스트보다 유리하게 하는 것도 가능하다. 장수명화를 실현시키기 위해서는 수명평가상 중요한 구조기기의 노화진단기술, 수명예측방법 및 수명을 좌우하고 교환이 곤란한 기기$\cdot$시스템의 보수기술$\cdot$공법 등에 관한 기술개발이 중요한 과제이다.

• 기계와재료
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• v.22 no.3
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• pp.80-87
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• 2010

본 연구는 현재 전기설비 가운데 주요부위의 절연상태를 지속적으로 감시하기위한 여러 제약조건 내에서 효과적인 무선센서네트워크를 적용하는 것이다. 따라서 본 연구에서는 전기설비에서 발생하는 여러 환경인자 가운데 일정량의 노화(열화)가 진행되었을 E 발생할 수 있는 공기 중 전기 코로나방전을 감시하고 그와 관련된 환경인자를 지속적으로 감시하기 위한 네트워크로 무선센서네트워크를 조사하고 적용대상에 맞는 네트워크 알고리즘을 분석하였다. 선정한 방식의 라우팅 알고리즘을 유사한 방식을 사용하는 알고리즘과 동일한 조건에서 시뮬레이션을 수행한 결과 가장 적합하다고 판단되는 LEACH-C 라우팅 알고리즘을 확인할 수 있었다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.508-509
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• 2000

우리나라의 굴 양식업은 1970년대 수하식 굴 양식기술 개발보급으로 계속 증대 발전하였으나, 연안의 산업화와 도시화에 의한 수질환경 악화 그리고 장기간의 집약적 양식에 의한 어장 노화와 양식 굴의 품종 열화 등에 원인하여 1990년대에 들어서면서 양식 생산량이 점차 감소하는 경향을 보이고 있다. 따라서 굴 양식의 지속적 생산 방안의 모색을 위하여 환경 적응력이 강한 굴 품종을 선발하고 변화된 어장환경을 이해하고자, 산지별 굴의 양성 해역별 양성시험을 실시하여 굴의 성장도, 비만도 및 생존율의 비교 조사와 그리고 환경조사 등을 실시하였다. (중략)

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.234-246
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• 2008

최근 기상이변과 빈번한 지진발생 및 기타 내외적 요인에 의한 노화/열화 등으로 인하여 댐 안전관리 문제가 국가의 재난관리 차원에서 주요 이슈가 되고 있다. 이에 본 논문에서는 기존 댐에 대한 안전관리를 효율적으로 수행할 수 있도록 하기 위해 개발된 댐 안전관리 시스템(Dam Safety Management System)의 세부구성 및 기능 등에 대하여 소개하고, 향후 선진화된 댐 안전관리를 위해 보완되어야 할 부분에 대한 제언을 하였다.

• Journal of the Korean Electrochemical Society
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• v.3 no.3
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• pp.162-168
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• 2000

The influence of phenolsulfunate concentrations on electroplating characteristics and electrochemical behaviors was investigated with a viewpoint of electrolyte aging using the circulation cell and potentiostate And comparison of tinplate coating appearance such as glossiness and Image clarify has been also studied with varying of phenolsulfonic acid (PSA) solutions. As the aging of electrolyte proceeded, the limiting current density was moved to a lower current density region by the limitation of mass transfer, and higher phenolsulfunate concentrations resulted in the narrower optimum current density range and deterioration of coating surface of tinplates. The difference of the limiting current density was not remarkable with increasing electrolyte temperature. Thus the electrolyte aging was attributed to the limitation of thermally-activated process such as mass transfer of reducible ions. It has also been considered that the accumulation of phenolsulfonate suppressed normal electrotinning reaction by reducing the mobility of stannous ions, taking into account of the smaller effect of electrolyte aging. Experiments showed similar polarization behavior between the electrolyte of high phenolsufonate solution and the aged one, which comes to conclude that the accumulation of phenolsulfonate is one of the major causes of electrolyte aging.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.4
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• pp.325-330
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• 2004

Several kinds of low voltage cables have been used in nuclear power plants for the supply of electric power, supervision, and the propagation of control signals. These low voltage tables must be inspected for safe and stable operation of nuclear power plants. In particular, the degradation diagnosis to estimate the integrity of low voltage rabies has recently been emphasized according to the long use of nuclear power plants. In order to evaluate their degradation, the surrounding temperature, hardness of insulation material, elongation at breaking point (EAB), etc. have been used. However, the measurement of temperature or hardness is not useful because of the absence of quantitative criteria; the inspection of a sample requires turning off of the power plant power; and, the electrical inspection method is not sufficiently sensitive from the initial through the middle stage of degradation. In this research, based on the theory that the ultrasonic velocity changes with relation to the degradation of the material, we measured the ultrasonic velocity as low voltage cables were degraded. To this end, an ultrasonic degradation diagnosis device was developed and used to measure the ultrasonic velocity with the clothing on the cable, and it was confirmed that the ultrasonic velocity changes according to the degradation of low voltage cables. The low voltage cables used in nuclear power plants were degraded at an accelerated rate, and EAB was measured in a tensile test conducted after the measurement of ultrasonic velocity. With the increasing degradation degree, the ultrasonic velocity decreased, whose potential as a useful parameter for the quantitative degradation evaluation was thus confirmed.

• Journal of IKEEE
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• v.27 no.4
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• pp.477-485
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• 2023

In this paper, the effect of AC ripple on the lifetime of lithium-ion batteries is experimentally analyzed. Bidirectional power conversion system(PCS) is used to increase the efficiency of energy storage systems (ESS). When connected to the grid, a current ripple with a frequency twice the grid frequency is applied to the battery due to its structure. Therefore, to analyze the effect of AC ripple on Li-ion battery aging, cycle life test are performed by applying charge/discharge profiles of DC current and DC+AC current ripple specifications. Based on the experimental results, direct current internal resistance (DCIR), incremental capacitance (IC), and surface temperature were analyzed. As a result, it is confirmed that AC ripple does not directly affect degradation and that battery degradation slows down after a certain cycle. These results can serve as a guideline for optimizing filters to reduce ripple on the battery side in applications where AC ripple occurs.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.6
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• pp.43-50
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• 2000

Design and experiments of a nondestructive testing system with a solenoid eddy current sensor to inspect deterioration of ASCR-OC (ACSR Outdoor Cross-linked Polyethylene Insulated Wires) usually used in HV overhead distribution lines in domestic areas in presented in this paper. Through corrosion mechanisms and deterioration results for ACSR-OC conductors are examined, it is shown that corrosion may lead to the reduction of the effective cross section area of conductors is proposed. The measurement system consisting of a constant current source with a RF frequency, a signal processing unit and a motor driver/ controller is designed and implemented. This instrument has such capabilities as detecting the sensor output and estimating diameter change of the testing conductors, continuously. As a result, it was verified that such corrosion detector system with an eddy current sensor can be shown good effectiveness for estimating the serious faults due to deterioration in overhead distribution lines and giving an early warming before severe aged conductor may lead to fail.