• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.836-842
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• 2016

When an accident occurs in the nuclear power plant, the faulted information might mislead to the high possibility of aggravating the accident. At the Fukushima accident, the operators misunderstood that there was no core exposure despite in the processing of core damage, because the instrument information of the reactor water level was provided to the operators optimistically other than the actual situation. Thus, this misunderstanding actually caused to much confusions on the rapid countermeasure on the accident, and then resulted in multiplying the accident propagation. It is necessary to be equipped with the function that informs operators the status of instrument integrity in real time. If plant operators verify that the instruments are working properly during accident conditions, they are able to make a decision more safely. In this study, we have performed various tests for the fault detection sensitivity of an data-driven empirical model to review the usability of the model in the accident conditions. The test was performed by using simulation data from the compact nuclear simulator that is numerically simulated to PWR type nuclear power plant. As a result of the test, the proposed model has shown good performance for detecting the specified instrument faults during normal plant conditions. Although the instrument fault detection sensitivity during plant accident conditions is lower than that during normal condition, the data-drive empirical model can be detected an instrument fault during early stage of plant accidents.

• Transactions of the KSME C: Technology and Education
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• v.3 no.3
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• pp.209-215
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• 2015

The effects of the mounting location of ICI cables on severe accident mitigation systems, specially IVR-ERVC (In-Vessel Retention by External Reactor Vessel Cooling) and core catcher (Ex-vessel corium retention and cooling system), are investigated. The effects of bottom-mounted ICI strategy on severe accident mitigation are summarized and advantages of top-mounted ICI to improve severe accident mitigation are also highlighted.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.3
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• pp.254-262
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• 2015

This paper presents 3D collision deformation modelling methodologies using photogrammetry for reconstruction of vehicle accidents. A vehicle's deformation shape in collision provides important information on how the vehicle collided. So effective measurement(scanning) and construction of a corresponding appropriate model are essential in the analysis of collision deformation shape for obtaining much information related to collision accident. Two measurement methods were used in this study: Indirect-photogrammetry which requires relatively small amount of photos or videos, and direct-photogrammetry which requires large amount of photos directly taken for the purpose of 3D modelling. When the indirect-photogrammetry method, which was mainly used in this study, lacked enough photographic information, already secured 2D numerical deformation data was used as a compensation. This made 3D collision deformation modelling for accident reconstruction analysis possible.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.4
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• pp.177-185
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• 2000

The deformation characteristics is one of the major factors to resume the crash configuration in collision accident reconstruction. Crash analysis are carried out using finite element method and body stiffness equations representing force-deformation relationship are derived, Two different crash conditions : 1) frontal barrier impact 2) frontal impact between cars are given for the derivation of the equations. The stiffness coefficient of equation by method 2) is larger than that by method. 1). Crash analysis between two vehicles is accomplished with three crash angles and three velocities for each angle condition. The deformations are measured for six selected points and deformation energies are calculated using the derived equations. Equation by method 2) results in better estimation of deformation energy than that by method 1) for all crush configurations. The estimated energies can be utilized as one of indices to identify the type of the collision accident result.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.2
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• pp.12-19
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• 2011

Real-world accident cases were investigated to understand injury characteristics of the elderly driver. A total 10 cases of car-to-car frontal crash accidents from passenger car including SUV claimed to domestic car insurance company were reviewed. The injury characteristics of the elderly were analyzed from personal information (gender, age), medical treatment record (medical certificate, curative days), vehicle information (model, air-bag, seatbelt) and damage information. This study showed that elderly driver has higher possibility of thorax injury than non-elderly's. Moreover, Injury type and severity were more severe than non-elderly driver at similar type accident conditions. Also, elderly driver's medical treatment period needs 3 times more than non-elderly driver's.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.5 no.2
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• pp.35-39
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• 2009

In this study, Event Type Analysis System (ETAS) is developed for the accident evaluation in nuclear power plant. The ETAS system can be used in supporting regulator and/or operator under event situation in nuclear power plants. The ETAS system can categorize the all transient events to 3 categories such as Down-2000, Down-2173, and Slow Fluctuation. We develop the program structure for ETAS system and web-based ETAS system. The ETAS system will be used as sub module of Knowledge-Based Event Evaluation Network (K-EvENT) which is developing for the against the accident in nuclear power plants.

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.1
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• pp.82-87
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• 2004

Hydrogen is considered to be the most important future energy carrier in many applications reducing greenhouse gas emissions significantly. To be applicable as energy carrier the safety issues associated with hydrogen applications needs to be investigated and fully understood. In order to analyze the risks associated with hydrogen applications, accidents associated with hydrogen in Korea from 1963 to 2002 have been analysed in this work. From analysis of accidents, we propose the necessity of research on hydrogen releases, dispersion in air, and explosion due to high hazardous of hydrogen.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.10
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• pp.1274-1284
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• 1999

The Regulatory Guide 1.82 recommends an analysis of hydraulic performance for sump of ECCS (Emergency Core Cooing System) when LOCA(Loss of Coolant Accident) occurs in a nuclear power plant. The present study deals with 3-dimensional, unsteady, turbulent and two-phase flow simulation to examine the behavior of mixture of reactor coolant and debris near the floor of containment building in conjunction with appropriate assumptions. The dispersed solid model has been adjusted to the interfacial momentum transfer between reactor coolant and debris. According to the results, the counterclockwiserecirculation zone had been formed in the region between sump and connection aisle about 376 second after LOCA occurs. The debris thickness accumulated on a sump screen periodically increases or decreases up to 2000 second, afterwards its peak decreases.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.5
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• pp.136-144
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• 2013

An extensive real world in-depth crash accident data is needed to make a precise occupant injury risk prediction at crash accidents which might be a critical information from the scene of the accident in ACNS(Automatic Crash Notification System). However it is rather unfortunate that there is no such a domestic database unlike other leading countries. Therefore we propose a numerical method, i.e., crash simulation using a sled model to make a virtual database that can substitute car crash database in real world. The proposing crash injury risk prediction is validated against a limited domestic crash accident data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.11
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• pp.2101-2106
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• 2009

The power system state estimation and prediction are very important for operation. Because that accidents of the Power system are the cause that many devices and etc are damaged. Currently, almost every power systems have 2nd,3rd back-upsystem for prevention of accident. But prevention of accident by miss-operation, due to operator or miss data, has not acounter plan. Because, we need to estimate the power system for correcting miss data and preventing miss operation by operator. We suggest algorithm for integrity of power system network data.