• Nuclear Engineering and Technology
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• v.37 no.6
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• pp.537-556
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• 2005

A primary-pipe rupture accident is one of the design-basis accidents of a High-Temperature Gas-cooled Reactor (HTGR). When the primary-pipe rupture accident occurs, air is expected to enter the reactor core from the breach and oxidize in-core graphite structures. This paper describes an experiment and analysis of the air ingress phenomena and the method fur the prevention of air ingress into the reactor during the primary-pipe rupture accident. The numerical results are in good agreement with the experimental ones regarding the density of the gas mixture, the concentration of each gas species produced by the graphite oxidation reaction and the onset time of the natural circulation of air. A hydrogen production system connected to the High-Temperature Engineering Test Reactor (HTTR) Is being designed to be able to produce hydrogen by themo-chemical iodine-Sulfur process, using a nuclear heat of 10 MW supplied by the HTTR. The HTTR hydrogen production system is first connected to a nuclear reactor in the world; hence a permeation test of hydrogen isotopes through heat exchanger is carried out to obtain detailed data for safety review and development of analytical codes. This paper also describes an overview of the hydrogen permeation test and permeability of hydrogen and deuterium of Hastelloy XR.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.1
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• pp.26-32
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• 2014

Mental fatigue is inevitable in the workplace. Since mental fatigue can lead to decreased efficiency and critical accidents, it is important to manage mental fatigue from the viewpoint of accident prevention. An experiment was performed to evaluate mental fatigue using the formant frequency analysis of human voices. The experimental task was to mentally add or subtract two one-digit numbers. After completing the tasks with four different levels of mental fatigue, subjects were asked to read Korean vowels and their voices were recorded. Five vowel sounds of "아", "어", "오", "우", and "이" from the voice recorded were then used to extract formant 1 frequency. Results of separate ANOVAs showed significant main effects of mental fatigue on formant 1 frequencies of all five vowels concerned. However, post-hoc comparisons revealed that formant 1 frequencies of "아" and "어" were most sensitive to mental fatigue level employed in this experiment. Formant 1 frequencies of "아" and "어" significantly decrease as the mental fatigue accumulates. The formant frequency extracted from human voice would be potentially applicable for detecting mental fatigue induced during industrial tasks.

• Journal of the Korea Safety Management & Science
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• v.19 no.1
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• pp.53-62
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• 2017

Full embroidery industrial accidents in recent years has shown a declining trend. But disaster embroidery of domestic construction industry were more than 20,000 deaths per year is about 500 people. The government has introduced a construction site often changing the recruitment of new construction based on health and safety as an alternative to road safety education training yisuje of construction workers, daily work periods short. Certificate of Basic OSH Training in Constructions had also been evaluated as successful by reducing the accident rate problem. It is conducted in private educational institutions has occurred on the friction between workers and employers and training costs are difficult to approach workers in the education standards for such facilities due to the superintendent. Educational institutions are institutions that have been caused by excessive competition lowered levels of education. There is also a lack of evaluation that the training is limited to the basic safety knowledge. These details are brought formal safety education purposes only and is introducing the results of other self jyeotgi difficult to reap the proceeds to good effect. In this study, we propose a plan for improving operational problems and enemy status based on research data presented after the Certificate of Basic OSH Training in Construction.

• Journal of the Korea Safety Management & Science
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• v.20 no.3
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• pp.1-9
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• 2018

This study is intended to look into the effect of construction safety supervision system on risk control and reduction. To achieve this, a survey was carried out to 114 companies in construction, ordering, contract and management. The overall findings were as follows. The effect of construction safety supervision system on risk control and reduction showed that factors of supervision system, supervision cost and supervision method had a positive effect on risk control and reduction. And their perception of the introduction of safety supervision system in construction sites according to process showed that there was a difference between them according to the field of ordering, contract and supervision. There was the biggest difference between owner and contractor in double supervision system, but no difference between them in the perception of risk reduction. These results show that all ordering, contract and supervision are positively needed for the introduction of construction safety supervision. This means that there is a difference between owner and contractor in the perception of process according to system operation. All companies agree to system improvement by the settlement of safety supervision system for the prevention of safety accidents and safe construction, but the systematic complement of safety supervision is the burden of contractor. And there is a big difference between owner and contractor in the perception of responsibility and concern for cost burden.

• Journal of Construction Engineering and Project Management
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• v.8 no.1
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• pp.10-21
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• 2018

Many construction projects involve a plethora of safety-related problems that can cause loss of productivity, diminished revenue, time overruns, and legal challenges. Incorporating data collection and analytics methods can help overcome the root causes of many such problems. However, in a dynamic construction workplace collecting data from a large number of resources is not a trivial task and can be costly, while many contractors lack the motivation to incorporate technology in their activities. In this research, an Android-based mobile application, Preemptive Construction Site Safety (PCS2) is developed and tested for real-time location tracking, trajectory prediction, and prevention of potential collisions between workers and site hazards. PCS2 uses ubiquitous mobile technology (smartphones) for positional data collection, and a robust trajectory prediction technique that couples hidden Markov model (HMM) with risk-taking behavior modeling. The effectiveness of PCS2 is evaluated in field experiments where impending collisions are predicted and safety alerts are generated with enough lead time for the user. With further improvement in interface design and underlying mathematical models, PCS2 will have practical benefits in large scale multi-agent construction worksites by significantly reducing the likelihood of proximity-related accidents between workers and equipment.

• Journal of the Korean Institute of Gas
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• v.22 no.1
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• pp.9-17
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• 2018

In the consideration of the working conditions, which have several kinds of works operating at the same time, at construction sites, it is difficult to prevent industrial accidents. There are a number of works to employ flammable materials and hot works simultaneously operated without fire protection systems. It causes a huge fire and casualties. In this research to analyze an accident case, the reasonable prevention methods are suggested throughout the property tests for the organic solvents and the analysis of the behavior for vapour cloud in the underground area of the construction site.

• Journal of the Korean Society of Safety
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• v.28 no.1
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• pp.137-143
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• 2013

Cultural heritage passing down to posterity is a global concern. But there are many culture heritage that not remained to now disappeared by various disasters. It is told that disaster is learnt from disaster. The most fundamental task in disaster prevention is to collect and analyze cases of accidents so as not to repeat a disaster. In other words, an analysis of various disaster-related materials and their countermeasures in the Joseon period is an actual condition-based phenomenological methodology used to prevent disasters at cultural properties today. In this context, it is important to collect histories of disasters in the Joseon period, to extract disaster-related historical data and to categorize the data to build a disaster literature database. This study has produced [Database of Disasters in the Joseon Era], a collection of articles on fire outbreaks based on The Annals and The Daily Records belonging to the Memory of the World. On the basis of this chronology, human and property damages caused by fires in Joseon have been examined, identified by districts, as well as disaster technologies, have been analyzed. It has also built disaster vulnerability maps in the Joseon Dynasty Era.

• Journal of the Korean Institute of Gas
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• v.2 no.2
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• pp.12-17
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• 1998

The number of fuel gas accidents is increasing in domestic fuel gas facilities as increasing the supply area. To prevent gas accident, the government institutions related to fuel gas industry partly collected and managed the information of physical properties and safety data. Due to the overlap of data between institutions, collecting and managing the safety information was inefficient. The purpose of this research is developing geographic information system which providing the information of quantitative risk assessment, accident prevention plan, and efficient sharing and managing of the system.

• Explosives and Blasting
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• v.32 no.3
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• pp.26-36
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• 2014

A survey for understanding the opinion about the safety and economy of different types of detonators used in domestic tunnel construction was carried out for total 345 people in related areas. From the result, it was found that 86.7% of the surveyed people felt non-electric detonator was safe. From the experimental points that the cost of detonators is in charge of 8.1% in overall tunnel blasting cost, and the utilization of non-electric detonators will also contribute to the prevention of blasting accidents by the electrical safety, this study can help providing opinions and basic data collected from related areas to manufacturing companies, police department, and companies ordering tunnel construction.

• Journal of the Korean Society of Safety
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• v.20 no.3 s.71
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• pp.91-97
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• 2005

The research on the explosive limits is one of fundamental fields of combustion process, and information on the explosive limits of mixture of fuel and oxidant, with or without additives, is very important for the prevention in industrial fire and explosion accidents. Explosive limits of all compounds and solvent mixtures can be calculated with the appropriate use of the fundamental laws of Raoult, Batten, Le Chatelier and MRSM(modified response surface methodology) model. In this study, the reference values of lower explosive limits(LEL) of the ethanol+toluene+ethylacetate system were compared with the calculated values by using the solution thermodynamics and the MRSM model, respectively. The values calculated by the proposed equations were a good agreement with literature data within a few percent. By means of this methodology, it is possible to evaluate reliability of experimental data of the lower explosive limits of the flammable mixtures. Also, from given results, it is possible to predict explosive limits of the other flammable liquid mixtures used in the chemical process by the use of the proposed equations.