• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1894-1895
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• 2007

It is excitation system for nuclear emergency generator that is to startup automatically and sequentially supply essential loads with power. There are static type and alternating exciter, etc in its excitation system. An object of study is static excitation system which power is taken from power potential transformer and power current transformer. It is to complement curtailment of excitation system ability at happening short accidents. And Startup mode are quick startup and slow startup, etc. Its characteristic is looked into in this paper.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.2
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• pp.79-86
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• 2014

This paper describes an integrity evaluation method for emergency diesel generator(EDG) and rotor part of EDG. EDG is a very important equipment in the nuclear power plant(NPP). EDG supplies electricity to the safety-related equipments for the safety shut down of NPP in an emergency situation of earthquake. The safety of the rotor part of EDG is also important during seismic impact from earthquake. The finite element modelling of the EDG including rotor part was constructed. The modal analysis of EDG was firstly performed. The first natural frequency was calculated and revealed higher than the cutoff frequency of seismic spectrum. Then the stress analysis was done to compare with the allowable stress. The safety of the rotor part was investigated by the finite element analysis of the rotor and journal bearing interaction to find film thickness and critical speed. The seismic load was applied to rotor part in a manner that the load was a weighted static load. Analysis results showed that the maximum stress was within the range of allowable stress and the film thickness is larger than the permissible minimum thickness, and the critical speed was out of the operating speed. Hence, the structural and dynamic integrity of EDG could be confirmed by the numerical analysis method used in this paper. However, dynamic analysis of a rotating rotor and supporting bearing with the seismic impact needs to be investigated in a more rigorous method since the seismic load to the rotating part complicates the behavior of rotating system.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11a
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• pp.348-353
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• 1996

본 논문은 그 동안 원자력발전소 비상디젤발전기(Emergency Diesel Generator : EDG)의 신뢰도 계산에 사용되어 온 Wyckoff 방법의 문제점을 지적하고, 새롭게 Parametric Empirical Bayes(PEB) 방법의 적용을 제안하고자 한다. Wyckoff 방법은 단순히 성공률을 계산하여 그 값을 EDG의 신뢰도로 간주하고 있어 많은 모순점을 내포하고 있다고 지적되어 오고 있다. Martz에 의해 제안된 PEB 방법은 과거의 경험적 자료를 신뢰도 분석에 이용함으로서 계산된 신뢰도의 정도를 높히는 새로운 계산법이라 할 수 있다. 따라서, 본 논문에서는 국내에서 취득한 EDG 운전자료들을 이용하여 Wyckoff 방법과 PEB 방법에 의한 신뢰도를 계산하고 그 결과를 비교하여 PEB 방법의 효용성을 검토하였다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.666_667
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• 2009

원자력발전소의 비상전력계통은 소외정전 시 발전소 안전정지에 필요한 안전관리 설비에 비상전력을 공급하는 계통으로 비상전력계통 모선에 비상디젤발전기(Emergency Diesel Generator : EDG)가 설치되어 있다. 본 논문에서는 국내 중수로형 원자력 발전소에 대해서 최초로 주기적 안전성 평가(Periodic Safety Review : PSR)을 수행한 결과를 기술하였다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2038-2039
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• 2008

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2007.04a
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• pp.128-133
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• 2007

• Nuclear Engineering and Technology
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• v.49 no.2
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• pp.327-334
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• 2017

Common-cause failure (CCF) events can significantly impact the availability of safety systems of nuclear power plants. For this reason, the International Common Cause Data Exchange (ICDE) project was initiated by several countries in 1994. Since 1997 it has been operated within the Organisation for Economic Co-operation and Development (OECD)/Nuclear Energy Agency (NEA) framework and has successfully been operated over six consecutive terms (the current term being 2015-2017). The ICDE project allows multiple countries to collaborate and exchange CCF data to enhance the quality of risk analyses, which include CCF modeling. As CCF events are typically rare, most countries do not experience enough CCF events to perform meaningful analyses. Data combined from several countries, however, have yielded sufficient data for more rigorous analyses. The ICDE project has meanwhile published 11 reports on the collection and analysis of CCF events of specific component types (centrifugal pumps, emergency diesel generators, motor operated valves, safety and relief valves, check valves, circuit breakers, level measurement, control rod drive assemblies, and heat exchangers) and two topical reports. This paper presents recent activities and lessons learnt from the data collection and the results of topical analysis on emergency diesel generator CCF impacting entire exposed population.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2036-2037
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• 2008

An Emergency Diesel Generator (EDG) manufactured by a French company Wartsila SACM, is a tandem type engine, consisted of two 10 cylindered diesel engines on each side. Manual provided by the manufacturer states that engine bearing requires inspection every 15 years. However, it is difficult for an inspector to access through a manhole located in the lower compartment of engine. Furthermore, during a routine or scheduled maintenance, it is not possible to disassemble main engine bearing and crank shaft, and perform inspection. Two methodologies are suggested here to resolve the problem. One method is to lift the engine and partially perform the maintenance service, and the other method is to disassemble the engine completely and to perform maintenance service by the manufacturer. Pros and cons of two methodologies were thoroughly compared.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.6
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• pp.69-78
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• 2007

In this study, for the evaluation of seismic safety of the isolated Emergency Diesel Generator (EDG) System more quantitatively, the seismic fragility analysis method were proposed. Using the proposed method, seismic fragility analysis performed and a seismic risk of EDG system was present. The fragility analysis performed not for an existing EDG system but also for an isolated EDG system which increases the seismic capacity. At first, numerical models for existing and isolated EDG system were constructed and seismic response analysis performed according to input seismic waves and peak ground accelerations. An uncertainty factors and failure modes of both fixed and isolated EDG system were assumed for fragility analysis. The HCLPF values were evaluated for the compare the improvement effect using the isolation system. As a result, the isolation system can make better the seismic fragility of EDG system, but the failure of isolation system was govern the behavior of whole system.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.3 s.55
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• pp.63-72
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• 2007

The Emergency Diesel Generator (EDG) is a very important equipment for the safety of a Nuclear Power Plant (NPP). In this study, the operating vibration of three kinds of EDG systems was measured. The target EDG systems are Yonggwang 5 unit and Ulchin 2 and 3 units. The Yonggwang 5 and Ulchin 3 unit EDG systems are the same type but the foundation systems are different. One is an anchor bolt type and the other is a spring and viscous-damper type. The purpose of these measurements is for a verification of the vibration isolation effect depending on the foundation system. As a result, It can be said that the spring and viscous damper system of the EDG performed better for the vibration isolation than that of anchor bolt type.