• Journal of the Korean Institute of Gas
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• v.11 no.1 s.34
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• pp.18-22
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• 2007

The fault current through the earth originated from a power line ground fault might cause arcing through the soil to an adjacent pipeline, which might bring about not only a catastrophic accident such as gas explosion and oil leakage but also a hazard to the safety of workers responsible for the maintenance and repair of the pipeline. In this paper we investigated the arcing phenomena through soil between a power line tower and a pipeline and outlined the standards for the separation distance of a buried pipeline adjacent to the power line tower.

• Nuclear Engineering and Technology
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• v.49 no.2
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• pp.360-372
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• 2017

Many advanced reactor designs rely on passive systems to fulfill safety functions during accident sequences. These systems depend heavily on boundary conditions to induce a motive force, meaning the system can fail to operate as intended because of deviations in boundary conditions, rather than as the result of physical failures. Furthermore, passive systems may operate in intermediate or degraded modes. These factors make passive system operation difficult to characterize within a traditional probabilistic framework that only recognizes discrete operating modes and does not allow for the explicit consideration of time-dependent boundary conditions. Argonne National Laboratory has been examining various methodologies for assessing passive system reliability within a probabilistic risk assessment for a station blackout event at an advanced small modular reactor. This paper provides an overview of a passive system reliability demonstration analysis for an external event. Considering an earthquake with the possibility of site flooding, the analysis focuses on the behavior of the passive Reactor Cavity Cooling System following potential physical damage and system flooding. The assessment approach seeks to combine mechanistic and simulation-based methods to leverage the benefits of the simulation-based approach without the need to substantially deviate from conventional probabilistic risk assessment techniques. Although this study is presented as only an example analysis, the results appear to demonstrate a high level of reliability of the Reactor Cavity Cooling System (and the reactor system in general) for the postulated transient event.

• Korean Journal of Hazardous Materials
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• v.6 no.2
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• pp.87-94
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• 2018

The study is aimed to analyze the MSDS awareness as per the properties, including general characteristics, of laboratory workers in university. It conducted the self-administered survey on the subject of 780 laboratory workers engaging in research activities in three university from February to May, 2017. Among them, it analyzed 686 cases except 94 of them, lacking content. As a result, education experience of MSDS, necessity of education, usage experience of MSDS, installation, comprehension, and accessibility showed a strategically significant difference in the recognition of MSDS. According to the categorical importance of MSDS, "the first aid measures" directly related to life was most significantly considered. It is estimated that it will contribute to prevention of safety accident by strengthening education on MSDS and increasing the level of awareness for laboratory workers.

• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.793-803
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• 2021

The small PWR has been paid more and more attention due to its diversity of application and flexibility in the site selection. However, the large core power density, the small containment space and the rapid accident progress characteristics make it difficult to control the containment pressure like the traditional PWR during the LOCA. The pressure suppression system has been used by the BWR since the early design, which is a suitable technique that can be applied to the small PWR. Since the configuration and operating conditions are different from the BWR, the pressure suppression system should be redesigned for the small PWR. Conducting the experiments on the scale down test facility is a good choice to reproduce the prototypical phenomena in the test facility, which is both economical and reasonable. A systematic scaling method referring to the H2TS method was proposed to determine the geometrical and thermohydraulic parameters of the pressure suppression containment response test facility for the small PWR conceptual design. The containment and the pressure suppression system related thermohydraulic phenomena were analyzed with top-down and bottom-up scaling methods. A set of the scaling criteria were obtained, through which the main parameters of the test facility can be determined.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1804-1812
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• 2022

The aim of this paper is to assess the reliability and accuracy of the PSI standard method, used in many previous works, for the quantification of ND uncertainties in the SPERT-III RIA transient, by quantifying the discrepancy between the actual inserted reactivity and the original static reactivity worth and their associated uncertainties. The assessment has shown that the inherent S3K neutron source renormalization scheme, introduced before starting the transient, alters the original static reactivity worth of the transient CR and reduces the associated uncertainty due to the ND perturbation. In order to overcome these limitations, two additional methods have been developed based on CR adjustment. The comparative study performed between the three methods has showed clearly the high sensitivity of the obtained results to the selected approach and pointed out the importance of using the right procedure in order to simulate correctly the effect of ND uncertainties on the overall parameters in a RIA transient. This study has proven that the approach that allows matching the original static reactivity worth and starting the transient from criticality is the most reliable method since it conservatively preserves the effect of the ND uncertainties on the inserted reactivity during a RIA transient.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2011-2017
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• 2023

Gas submerged jet is an outstanding thermohydraulic phenomenon in pool scrubbing of fission products during a severe nuclear accident. Experiments were performed on the hydraulic characteristics in the ranges of air mass flux 0.1-1400 kg/m²s and nozzle diameter 10-80 mm. The results showed that the dependence of inlet pressure on the mass flux follows a power law in subsonic jets and a linear law in sonic jets. The effect of nozzle submerged depth was negligible. The isolated bubbling regime, continuous bubbling regime, transition regime, and jetting regime were observed in turn, as the mass flux increased. In the bubbling regime and jetting regime, the air volume fraction distribution was approximately symmetric in space. Themelis model could capture the jet trajectory well. In the transition regime, the air volume fraction distribution loses symmetry due to the bifurcated secondary plume. The Li correlation and Themelis model showed sufficient accuracy for the prediction of jet penetration length.

• Proceedings of the KIEE Conference
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• 2006.05a
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• pp.34-36
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• 2006

The number of confine-disease of elevator increases every year and then sudden rise, sudden stop, error of level indication, stand; those can bring to uneasiness of elevator passenger and malfunction accidents related life accident are increasing. For confirmation those malfunction accident, we are measuring and analyzing power quality(Sag, Interruption, Harmonic) of the actual site and evaluated the performance for stop and stating by testing the two imitation test equipment with EN12016(2004) standard level. This paper will be used data of the analysis for mutual relation between Power Quality and malfunction and fault of elevator.

• Journal of the Korean Society of Safety
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• v.31 no.4
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• pp.126-135
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• 2016

The purpose of this study is to develop risk assessment techniques and institutional analysis of domestic and international, the management techniques that can efficiently manage the harmful factor of the laboratory and to present the institutional measures that can be efficiently implemented. Due to a variety of adverse factors of laboratory, accidents of laboratory of various forms have occurred, but there is no risk assessment system in order to manage this effectively. So, we investigated this domestic existing risk assessment methods and the outside of the risk assessment system, and also analyzed accidents of domestic laboratory that occurred in 2014. In addition, we targeted the 24 laboratories in 21 universities to investigate the management of harmful factors of the laboratory and performed applying test for 12 domestic laboratories. Existing risk evaluation system, such as PMS, SMS, off-site impact assessment, since the industrial site is the subject, is a difficult problem to be directly applied to the laboratory of the research institute. So, we implemented management status and harmful factors survey and classified the research and development activities based on this data. Finally we developed "pre-hazards risk analysis method" to create each of the safety management measures. In addition, research activities personnel conducted voluntarily risk assessment, which is shared by institutions and government. It is presented the institutional system for safety management of laboratory. Its result, pre-hazards risk analysis method and institutionalization scheme will be able to achieve laboratory accident prevention system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.139-146
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• 2016

The purpose of this study is to investigate the necessity of safety awareness and education regarding the use of laboratories, and to foster safety awareness during intramural and extracurricular activities in high schools. The study conducted a questionnaire to 290 eleventh grade students of three high schools located in Seoul. The collected data were statistically analyzed. The result illustrates that 64.8% of students have experienced safety education during a regular class, 6.6% have experienced accidents, and 68.0% have experienced safety education during field activities. The result concludes that there is a lack of prior safety education as well as overall low awareness on the necessity of safety education. In particular, students who have experienced safety education recognizes the necessity of emergency education regarding laboratory accident more than those who did not receive such education. Thus, a systematic management of laboratory safety education and multilateral management measures for students' safety are required. There is a relatively high correlation between safety intention of R&D and Education factors and Community and Laboratory Safety Education. As much as there is a high safety demand regarding the laboratory instruments and experiment, it shows high intention of safety lab operation as well as count measurement of lab accident. This study recommends developing a laboratory safety education program and management methods appropriate for high school students.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.488-496
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• 2020

This study was based on nitrate chemical accidents at home and abroad. Toxic gases due to adverse reactions are generated in the workplace, laboratory, hospital, container damage, and chemical misinjection. Through a case review of possible situations and safety, this study analyzed various cases of accidents, accident status, accident type, cause of the accident, location of the accidents, etc. from 2014 to 2018. The plans for improvement in education and nitrate accidents were reviewed. As a result, 36 nitrate chemical accidents were investigated, including 16 careless worker accidents, eight transportation accidents, and 12 facilities shortages. Nitrate chemical accidents are occurring continuously. Based on this, the range of toxic effects using CARIS was calculated at the worst-case scenario, and the effective response range was measured through the damage impact range. For this purpose, the impact range was predicted based on the strengthening of safety education, emergency action plan and correlation, and the quantified data was identified. In addition, the reliability of the scope of impact was reviewed based on the correlation formula that could facilitate the evacuation of residents, and it was applied to actual accident scenarios of the workplace to present the effects of the accident response and preventive measures.