• Nuclear Engineering and Technology
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• 제46권6호
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• pp.817-824
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• 2014

To ensure the safety of research reactors, the water level must be maintained above the required height. When a pipe ruptures, the siphon phenomenon causes continuous loss of coolant until the hydraulic head is removed. To protect the reactor core from this kind of accident, a siphon breaker has been suggested as a passive safety device. This study mainly focused on two variables: the size of the pipe rupture and the timing of air entrainment. In this study, the size of the pipe rupture was increased to the guillotine break case. There was a region in which a larger pipe rupture did not need a larger siphon breaker, and the water flow rate was related to the size of the pipe rupture and affected the residual water quantity. The timing of air entrainment was predicted to influence residual water level. However, the residual water level was not affected by the timing of air entrainment. The experimental cases, which showed the characteristic of partical sweep-out mode in the separation of siphon breaking phenomenon [2], showed almost same trend of physical properties.

• 대한안전경영과학회지
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• 제19권1호
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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.

• 대한안전경영과학회지
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• 제5권4호
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• pp.31-44
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• 2003

Domestic industry calamity rate did decrease in large numbers by many efforts of the safety and health organizations. But that is low yet among the OECD countries. Calamities are started In most work inexperience and safety consciousness absence. So, we can know that education is how important. Domestic small and medium enterprises are in trend that industrial accident is increased by deterioration of hardware, not enough preparedness of safety equipments. But, the safety and health education had not been utilized so far effectively and applied systematically. Therefore, the most important among many means to reduce calamity is the safety and health education. An efficient education will supply suitable knowledge and technology to work people. And that will lead to prevent accident by building right habit and attitude. This research did the survey about problems of education that is enforced in small and medium enterprises. That survey is done to three groups of workers, administrators and managers. We compared domestic safety and health education system and advanced foreign system. And, analyzed problems and presented a solution. Finally, this research presented efficient operation model of the safety and health education suitable to domestic medium and small enterprises.

• Nuclear Engineering and Technology
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• 제47권7호
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• pp.827-837
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• 2015

Following a severe accident in a nuclear power plant, iodine is a major contributor to the potential health risks for the public. Because the amount of iodine released largely depends on its volatility, iodine's behavior in containment has been extensively studied in international programs such as International Source Term Programme-Experimental Program on Iodine Chemistry under Radiation (EPICUR), Organization for Economic Co-operation and Development (OECD)-Behaviour of Iodine Project, and OECD-Source Term Evaluation and Mitigation. Korea Institute of Nuclear Safety (KINS) has joined these programs and is developing a simplified, stand-alone iodine chemistry model, RAIM (Radio-Active Iodine chemistry Model), based on the IMOD methodology and other previous studies. This model deals with chemical reactions associated with the formation and destruction of iodine species and surface reactions in the containment atmosphere and the sump in a simple manner. RAIM was applied to a simulation of four EPICUR tests and one Radioiodine Test Facility test, which were carried out in aqueous or gaseous phases. After analysis, the results show a trend of underestimation of organic and molecular iodine for the gas-phase experiments, the opposite of that for the aqueous-phase ones, whereas the total amount of volatile iodine species agrees well between the experiment and the analysis result.

• Nuclear Engineering and Technology
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• 제42권4호
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• pp.394-413
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• 2010

The object of this paper is to identify the key elements that impact a radiation dose at EAB (Exclusion Area Boundary). This study is based on the AST (Alternative Source Terms) as defined in Regulatory Guide 1.183. The LOCA (Loss of Coolant Accident) and the LRA (Locked Rotor Accident) are selected as limiting cases. A sensitivity analysis of accidental behavior with respect to various parameters during LOCA and LRA at Kori Unit 1 is also undertaken for the following objectives: to determine the limiting parameters, to find the impact trend of the radiation dose, and to find the safety margin between AST and TID (Technical Information Document) methodologies. This work confirms that key parameters are particulate removal rate, decontamination factor, iodine chemical form, gap fraction, partitioning factor, and the impact of isotopes group. Comparing TID with AST, the radiation dose of TID is about 80% greater than that of AST under a LOCA, and about 60% greater than that of AST for the case of a LRA; thus the safety margin is remarkably increased when the AST is used. In this work, the sensitivity analysis results are presented in terms of a sensitivity index called the "NDD (Normalized Dose Difference)", which compares the impact of parameters with that of a reference case. These values are derived by using a combination of the leak rate (primary to secondary), iodine chemical form, gap fraction, partitioning factor, spray removal rate, source term, and other variables.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.19-33
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• 2024

In nuclear thermal-hydraulic system codes, most correlations used for vertical pipes, under downward two-phase flow, have been developed considering small pipes or pool systems. This suggests that there could be uncertainties in applying the correlations to accident scenarios involving large vertical pipes owing to the difference in the characteristics of two-phase flows, or flow conditions, between large and small pipes. In this study, we modified the Multi-dimensional Analysis of Reactor Safety KINS Standard (MARS-KS) code using correlations, such as the drift-flux model and two-phase multiplier, developed in a plant-scale air-inflow experiment conducted for a pipe of diameter 600 mm under downward two-phase flow. The results were then analyzed and compared with those based on previous correlations developed for small pipes and pool conditions. The modified code indicated a good estimation performance in two plant-scale experiments with large pipes. For the siphon-breaking experiment, the maximum errors in water flow for modified and original codes were 2.2% and 30.3%, respectively. For the air-inflow accident experiment, the original code could not predict the trend of frictional pressure gradient in two-phase flow as / increased, while the modified MARS-KS code showed a good estimation performance of the gradient with maximum error of 3.5%.

• Journal of Korean Neurosurgical Society
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• 제59권2호
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• pp.149-153
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• 2016

Objective : The aim of the present study is to estimate the incidence trend of head injury and the mortality based on traffic accident statistics and to investigate the impacts of rapid industrialization and economic growth on epidemiology of head injury in Korea over the period 1970-2012 including both pre-industrialized and post-industrialized stages. Methods : We collected data of head injury estimated from traffic accident statistics and seven hospital based reports to see incidence trends between 1970 and 2012. We also investigated the population structure and Gross National Income (GNI) per capita of Korea over the same period. The age specific data were investigated from 1992 to 2012. Results : The incidence of head injury gradually rose in the 1970s and the 1980s but stabilized until the 1990s with transient rise and then started to decline slowly in the 2000s. The mortality grew until 1991 but gradually declined ever since. However, the old age groups showed rather slight increase in both rates. The degree of decrease in the mortality has been more rapid than the incidence on head injury. Conclusion : In Korea during the low income stage, rapid industrialization cause considerable increase in the mortality and the incidence of head injury. During the high income stage, the incidence of head injury gradually declined and the mortality dropped more rapidly than the incidence due to preventive measures and satisfactory medical care. Nevertheless, the old age groups revealed rather slight increase in both rates owing to the large population structure and the declining birth rate.

• 한국안전학회지
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• 제22권2호
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• pp.59-66
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• 2007

As the need of handling heavy materials increases, various cranes are used in industries. However, the effectiveness of crane also entails industrial accidents such as falling, constriction etc. In fact, the number of fatal accidents caused by crane is still high in Korea. To find out the causes of the accidents in terms of human error, we developed a man-machine system model that consists of two axes; human information processing and crane life cycle. In the human information processing dimension, we simplified it as five functions; sensing and perception, decision making and memory, response etc. In the crane life cycle dimension, we divided it into nine phases; design, production, operation etc. For the 152 fatal accident records during 1999-2006 years, we classified them into 45 cells made by two axes. Then we identified the preceding causes of the classified crane accident based on performance shaping factors. As the results of statistical analysis, the overall trend of crane fatal accidents was described. For the cause analysis, wrong decision making in work plan phase shows the highest frequency. Next, the poor information input in crane operation followed in accident frequency. In ergonomics view, the problems of interface design in displays and controls made 11.8% of fatal accidents. Following the analysis, several ergonomic design guidelines to prevent crane accidents were suggested.

• 산업경영시스템학회지
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• 제40권1호
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• pp.65-78
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• 2017

Even though cars have a good effect on modern society, traffic accidents do not. There are traffic laws that define the regulations and aim to reduce accidents from happening; nevertheless, it is hard to determine all accident causes such as road and traffic conditions, and human related factors. If a traffic accident occurs, the traffic law classifies it as 'Negligence of Safe Driving' for cases that are not defined by specific regulations. Meanwhile, as Korea is already growing rapidly elderly population with more than 65 years, so are the number of traffic accidents caused by this group. Therefore, we studied predictive and comparative analysis of the number of traffic accidents caused by 'Negligence of Safe Driving' by dividing it into two groups : All-ages and Elderly. In this paper, we used empirical monthly data from 2007 to 2015 collected by TAAS (Traffic Accident Analysis System), identified the most suitable ARIMA forecasting model by using the four steps of the Box-Jenkins method : Identification, Estimation, Diagnostics, Forecasting. The results of this study indicate that ARIMA $(1, 1, 0)(0, 1, 1)_{12}$ is the most suitable forecasting model in the group of All-ages; and ARIMA $(0, 1, 1)(0, 1, 1)_{12}$ is the most suitable in the group of Elderly. Then, with this fitted model, we forecasted the number of traffic accidents for 2 years of both groups. There is no large fluctuation in the group of All-ages, but the group of Elderly shows a gradual increase trend. Finally, we compared two groups in terms of the forecast, suggested a countermeasure plan to reduce traffic accidents for both groups.

• 한국도로학회논문집
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• 제14권6호
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• pp.103-110
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• 2012

PURPOSES : In Korea, over 70 percent of the land consists of mountainous and rolling area. Thus, tunnels continue its upward trend as road network are extended. In these circumstances, the importance of tunnel has been increased nowadays and then its safety investigation and research should be performed. This study is focus on confirming and improving the safety of tunnel. On tunnel hood, sunglare effect can irritate driver's behavior instantly and this can result in incident. METHODS : The study of this phenomenon is rarely conducted in domestic and foreign papers, so there is no proper measure for this. This study analyzes the driving environment of the effect of sunglare effect on tunnel hood. RESULTS : Traffic accidents stem from complex set of factors. This study build the Traffic Accident Prediction Models to find out the effect of sunglare effect on tunnel's hood. The independent variables are traffic volume, geometric design of road, length of tunnel and road side environment. Using these variables, this model estimates accident frequency on tunnel hood by Poisson regression model and Negative binomial regression model. Although Poisson regression model have more proper goodness of fit than Negative binomial regression model, Poisson regression model has overdipersion problem. So the Negative binomial regression model is used in this analysis. CONCLUSIONS : Consequently, the model shows that sunglare effect can play a role in driving safety on tunnel hood. As a result, the information of sunglare effect should be noticed ahead of tunnel hood so this can prevent drivers from being in hazard situation.