• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1080-1084
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• 2007

Recently, as demands of new railway and the relocation of existing line, a number of tunnel structures have been constructed. Tunnel structures contribute to minimize the cost and time of transport, but in case of railway fire accident bring serious damages of human life caused by narrowness of shelter, smoke and high temperature, difficulty in rescue. For that reason, at the beginning of plan of tunnel, the optimum design of safety facility in tunnel for minimizing the risks and satisfying the safety standard is needed. In this study, QRA(Quantitative Risk Analysis) technique is applied to design of railway tunnel for assuring the safety function and estimating the risk of safety. The case study is carried out to verify the QRA technique for railway tunnels in Iksan-Sili.

• Journal of the Korean Society of Safety
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• v.26 no.2
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• pp.6-12
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• 2011

The failure probabilities of pipes in nuclear power plants due to stress corrosion are obtained using the P-PIE program, which is developed for evaluating failure probability of pipes based on the existing PRAISE program. Leak, big leak and LOCA(loss of coolant accident) probabilities are calculated as a function of operating time for several pipes in a domestic nuclear plant. The sensitivity analysis is also performed to find out the important parameters for the failure of pipes due to stress corrosion. The results show that the steady state oxygen concentration and steady state temperature are important parameters and failure probability is very low when the oxygen concentration is maintained according to the regulation.

• Journal of the Korea Safety Management & Science
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• v.14 no.2
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• pp.103-112
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• 2012

The construction industry in Korea after the Korean-war has evolved until these days. But the construction industry accident severity rate and frequency is over then the All industry rate. This study analyzed the 'Disaster Statistical Yearbook' of the Korea Occupational Safety and Health Agency, based on the factors that affect construction accidents that is selected and fined the some factors the construction Disaster Prevention Factors. This study will develop the methodology for analyzes that the national qualification is effected to the construction industrial machine disaster prevention status. It suggest two ways to the establishment of disaster trends. First way is the disaster quantitative analysis and second way is comparing the statistical data and the analysis of expert opinion.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.6
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• pp.72-77
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• 2007

A safety-related equipment for the nuclear power plant should be needed an equipment qualification. In this paper, the approach, methods, philosophies, and procedures for qualifying the large squirrel-cage induction electric pump motors for use in ULCHIN 5, 6 Nuclear Power Plants were presented. The method of qualification is a combination of experimental test and analytic method, which is composed of radiation exposure test, seismic simulation test, thermal aging analysis for non-metallic materials, and seismic analysis. The results showed that the motor performed its safety function with no failure mechanism under postulated service conditions.

• Journal of the Korean Society of Safety
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• v.20 no.3 s.71
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• pp.1-8
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• 2005

The industrial induction motor is widely used in the rotating electrical machine for the transmission of power. It is very reliable equipment, but it could lead to the loss of production and lift when failure occurs. Therefore, the failure data is acquired and analyzed by attaching an exclusive instrument to existing induction motor. However, these instruments could lead to side effects, increasing the production costs, because they are very expensive. The purpose of this study is the development of an induction motor bearing failure diagnosis system constructed using LabVIEW which can be supplied the kernelled function, process monitoring and current signature analysis. In addition, the availability and reasonability of the constructed system was examined for an induction motor with failure defects in outer raceway and ball bearing. From the results, it shows that failure diagnosis system constructed is useful for real-time monitoring with detection of bearing defects over the web.

• Journal of the Korean Society of Safety
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• v.19 no.1
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• pp.102-107
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• 2004

Performance based design is a recent evolutionary step in the process of designing fire protection systems. In essence, it is a logical design process resulting in a solution that achieves a specified performance. Sometimes the prescriptive solutions presented in various codes and standards are too expensive or inflexible. Often the solutions do not and enables optimization of a solution for cost and function. In this study, performance based design was carried out to determine the extent of passive fire protection for oil terminal facilities. The results of performance based design were compared with those of prescriptive code based design. Performance based design is not always more economic than prescriptive code based design but provides more reliable and effective design that is fit for the purpose.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.2
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• pp.98-112
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• 2018

Intentional aggressive driving (IAD) is a very dangerous driving behavior that threatens to attack the adjacent vehicles. Most existing studies have focused on the independent driving characteristics of attack drivers. However, the identification of interactions between the offender and the victim is necessary for the traffic safety analysis. This study established multi-agent driving simulation environments to systematically analyze vehicle interactions in terms of traffic safety. Time-to-collision (TTC) was adopted to quantify vehicle interactions in terms of traffic safety. In addition, a exponential decay function was further applied to compare the overall pattern of change in crash potentials when IAD events occurred. The outcome of this study would be useful in developing policy-making activities to enhance traffic safety by reducing dangerous driving events including intentional aggressive driving.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.2
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• pp.161-172
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• 2017

To evaluate radiological impact from the operation of a low- and intermediate-level radioactive waste disposal facility, a logical presentation and explanation of expected accidental scenarios is essential to the stakeholders of the disposal facility. The logical assessment platform and procedure, including analysis of the safety function of disposal components, operational hazard analysis, operational risk analysis, and preparedness of remedial measures for operational safety, are improved in this study. In the operational risk analysis, both design measures and management measures are suggested to make it possible to connect among design, operation, and safety assessment within the same assessment platform. For the preparedness of logical assessment procedure, classification logic of an operational accident is suggested based on the probability of occurrence and consequences of assessment results. The improved assessment platform and procedure are applied to an operational accident analysis of the Korean low- and intermediate-level radioactive waste disposal facility and partly presented in this paper.

• Structural Engineering and Mechanics
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• v.64 no.3
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• pp.293-299
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• 2017

Submarine collisions is one of the major hazardous factor for Submerged Floating Railway Tunnel (SFRT) and this study presents the safety evaluation for submarine collision to SFRT by using theoretical approach. Simplified method to evaluate the collision safety of SFRT was proposed based on the beam on elastic foundation theory. Firstly, the time history load function for submarine collision was obtained by using one-degree-of-freedom vibration model. Then, the equivalent mass and stiffness of the structure were calculated, and the collision responses of SFRT were evaluated. Finite element analysis was conducted to verify the proposed equations, and it can be found that the collision responses, such as deflection, and acceleration, agreed well with the proposed equations. Finally, derailment condition for high speed train in SFRT due to submarine collision was proposed.

• Nuclear Engineering and Technology
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• v.42 no.4
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• pp.460-467
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• 2010

In this study, the parameters of the feedwater control system (FWCS) of the OPR1000 type nuclear power plant (NPP) are optimized by response surface methodology (RSM) in order to acquire better level control performance from the FWCS. The objective of the optimization is to minimize the steam generator (SG) water level deviation from the reference level during transients. The objective functions for this optimization are relationships between the SG level deviation and the parameters of the FWCS. However, in this case of FWCS parameter optimization, the objective functions are not available in the form of analytic equations and the responses (the SG level at plant transients) to inputs (FWCS parameters) can be evaluated by computer simulations only. Classical optimization methods cannot be used because the objective function value cannot be calculated directely. Therefore, the simulation optimization methodology is used and the RSM is adopted as the simulation optimization algorithm. Objective functions are evaluated with several typical transients in NPPs using a system simulation computer code that has been utilized for the system performance analysis of actual NPPs. The results show that the optimized parameters have better SG level control performance. The degree of the SG level deviation from the reference level during transients is minimized and consequently the control performance of the FWCS is remarkably improved.