• Nuclear Engineering and Technology
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• v.41 no.5
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• pp.617-648
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• 2009

Under the government supported long-term nuclear R&D program, the severe accident research program at KAERI is directed to investigate unresolved severe accident issues such as core debris coolability, steam explosions, and hydrogen combustion both experimentally and numerically. Extensive studies have been performed to evaluate the in-vessel retention of core debris through external reactor vessel cooling concept for APR1400 as a severe accident management strategy. Additionally, an improvement of the insulator design outside the vessel was investigated. To address steam explosions, a series of experiments using a prototypic material was performed in the TROI facility. Major parameters such as material composition and void fraction as well as the relevant physics affecting the energetics of steam explosions were investigated. For hydrogen control in Korean nuclear power plants, evaluation of the hydrogen concentration and the possibility of deflagration-to-detonation transition occurrence in the containment using three-dimensional analysis code, GASFLOW, were performed. Finally, the integrated severe accident analysis code, MIDAS, has been developed for domestication based on MELCOR. The data transfer scheme using pointers was restructured with the modules and the derived-type direct variables using FORTRAN90. New models were implemented to extend the capability of MIDAS.

• Child Health Nursing Research
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• v.9 no.2
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• pp.162-172
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• 2003

Purpose: The purpose of this study is to develop safety education program to prevent child accident and to improve the health of children by providing a safe environment. This program provide parents and children with information on how to prevent children from accident. Children especially can learn specific methods to avoid accident both at home, school and outside the home through safety education, which is based on problem solving. Method: This program was developed based on literature reviews, surveys and negotiation process. School aged children, parents, and teachers were interviewed to identify their educational needs based on their experiences related to child accident. During the 7th Annual Conference of Educational Courses in 1999, the Korean Educational Ministry examined the feasibility and compatibility of integrating the program into the current educational curriculum. Result: This program includes useful subjects such as safety education, preventive strategies, crisis management, guide for parent and teacher, resource persons, internet site and phone numbers of available hospital. Counseling is provided by researcher if needed. Conclusion: This program could be adequately utilized for prevention of child accident and creation of preventive strategies. It will also suggest an intervention strategy for injured children.

• The Journal of the Korea Contents Association
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• v.9 no.5
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• pp.249-256
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• 2009

The purpose of this study is to suggest the strategies of building disaster resistant communities to overcome communities destruction and vulnerability caused by the Hebei Spirit oil spill accident in Taean on December 7th, 2007. For accomplishing the purpose, we drew problems of approach based on context of community, governance strategy, and community-based approach. And based on the results of this analysis, suggestions were made as follows for building disaster resistant communities. First, when Hebei Spirit oil spill accident occurred we have been short of regional study and unreality of regional safety plan. For overcoming this points, we have need of activation of regional study and establishment of regional safety plan based on the bottom-up approach. Second, while the spill has brought a milestone activation of volunteer, we have not still efficient disaster management based on governance. So we have to establish network-governance to cooperate with government-business-private sector for efficient disaster management. Third, we argue that it is important to build social capital such as social networks, social contacts for community-based disaster resistant communities.

• Journal of Korean Society on Water Environment
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• v.23 no.1
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• pp.103-110
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• 2007

An efficient operational strategy using expert system for metro water supply systems in case of emergency situations is developed in this study. The emergency situations of the water supply systems are classified into three categories : pipeline system accident, machinery and electric facility accident and water quality accident. A PC-based expert system is developed using CLIPS for Seoul metro water supply system, Phase 1 & 2 system and Phase 3 & 4 system. Broad professional knowledges and experiences from the experts in the water supply systems have been collected systematically to construct the knowledge base. Decision-making in case of an emergency is based upon the professional knowledge so that a rational and efficient operational management can be available even in the absence of experienced expert. Especially the expert model developed in this study also provides a guide for pumping operation in case of pipeline accident to confirm that the proper pressure to all nodes in the system is supplied. The pipe network simulator KYPIPE has been consecutively executed by trial and error fashion for each pipeline in the system. The results from KYPIPE were included in the knowledge base to supplement the knowledge of the field engineers.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.17 no.2
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• pp.90-100
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• 2021

Molten corium-concrete interaction (MCCI) is one of the most important phenomena that can lead to the potential hazard of late containment failure due to basemat penetration during a severe accident. In this study, MCCI analytical models of the CORQUENCH code were prepared through verification calculations of several experiments, which had been performed using concrete types similar to those of the calandria vault floor in CANDU-6 plants. The behaviors of thermal-hydraulic variables related to MCCI phenomena were analyzed under the conditions of dry floor and water flooding during the severe accident stemming from a hypothetic station blackout. Uncertainty analyses on the ablation depth were also carried out. It was estimated that the concrete ablation was not interrupted due to the continuous MCCI process under the dry condition but was terminated within 24 hours under the water flooding condition. It was confirmed that the water flooding as a mitigating action was effective to achieve the quenching and thermal stabilization of the melt discharged from the calandria vessel, showing that the present models are capable of reasonably simulating MCCI phenomena in CANDU-6 plants. This study is expected to provide the technical bases to the accident management strategy during the late-phase severe accidents.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.152-161
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• 2022

We analyzed mitigation strategies for steam generator tube rupture (SGTR) accidents using MARS code under both full-power and low-power and shutdown (LPSD) conditions. In general, there are two approaches to mitigating SGTR accidents: supplementing the reactor coolant inventory using safety injection systems and depressurizing the reactor coolant system (RCS) by cooling it down using the intact steam generator. These mitigation strategies were compared from the viewpoint of break flow from the ruptured steam generator tube, the core integrity, and the possibility of the main steam safety valves opening, which is associated with the potential release of radiation. The "cooldown strategy" is recommended for break flow control, whereas the "RCS make-up strategy" is better for RCS inventory control. Under full power, neither mitigation strategy made a significant difference except for on the break flow while, in LPSD modes, the RCS cooldown strategy resulted in lower break and discharge flows, and thus less radiation release. As a result, using the cooldown strategy for an SGTR under LPSD conditions is recommended. These results can be used as a fundamental guide for mitigation strategies for SGTR accidents according to the operational mode.

• Journal of the Korea Safety Management & Science
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• v.15 no.1
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• pp.169-176
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• 2013

A government needs the investment expansion for the industrial accident prevention of the disadvantage group workers in order to improve the external phase and reliability. In this study, we analyze the current status of the development for safety and health material which is necessary for education of the disadvantage group workers. Firstly we find the problems that may occur when applying in domestic safety and health management system and then we'll propose a new method for safety and health material development and supply.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.473-478
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• 1997

A severe accident management strategy, in-vessel retention corium through external reactor vessel cooling(ERVC) is being studied worldwide as a means to prevent reactor vessel failure following a core melt accident. An evaluation of feasibility of this ERVC for a large Advanced Light Water Reactor (ALWR) is presented. To account for the coolability of corium and metal in the reactor vessel, a thermal analysis is performed using an existing method. Results show that the peak heat flux along the inner surface of the reactor vessel lower head has a relatively smaller margin than a small capacity reactor such as AP600 in regards with the critical heat flux attainable at the outer surface of the reactor vessel lower head.

• International Journal of Reliability and Applications
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• v.3 no.2
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• pp.61-80
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• 2002

Tree-harvesting worker data of 508 separate worker accidents are analyzed and an exploratory approach taken. The worker accident data cover a sample of five years. The scope of the study was the southeastern United States of America. As might be hypothesized, the chainsaw was the most hazardous type of tree-harvesting equipment. It accounted for 55％ of the tree-harvesting accidents. Most chainsaw accidents resulted in injuries to the lower extremities and were more frequent among younger employees. The probability of one or more chainsaw accidents occurring in any 30-day period was approximately 0.856. Chainsaw accidents were more likely to occur in late morning and early afternoon. We used statistical tools such as Pareto charts, c-charts and Ishikawa diagrams. Such tools are useful in diagnosing the root-cause of tree-harvesting worker accidents and help in developing preventive safety programs. Recommendations to help improve the quality of information of accident data collected by insurance companies and others are briefly given. The strategy and culture of continuous process improvements are stressed.

• Korean Journal of Construction Engineering and Management
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• v.1 no.2 s.2
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• pp.81-88
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• 2000

Planning and control for safety management executed by the head office is one of the most important parts for improving safety level of construction company. So this study is initiated with the purpose of suggesting an improvement strategy to perform effective and rational safety management at the head office. In order to investigate the current status of safety management of large construction firms in the Korean construction industry, the safety criteria related to the head office which are used in the Supermerit Certification System were chosen and examined by industry expert. The selected criteria are used for mail questionnaire. The survey was performed for 79 construction firms. Based on the 3-year average accident rate of 79 firms(1.20), the safety level of firms are classified. The safety improvement strategies for the below and the above are proposed respectively.