• Journal of the Korean Institute of Gas
• /
• v.25 no.4
• /
• pp.57-62
• /
• 2021

In this study, risk assessment was conducted in case of leakage of storage facilities (tube trailer) using the HyKoRAM program developed through international joint research. The high-pressure gas facilities in the hydrogen filling station are divided into four main categories: storage facilities (tube trailers), processing facilities (compressors), compressed gas facilities, and filling facilities (dispensers). Among them, the design specifications of the tube trailer, which is a storage facility, and the surrounding environmental conditions were reflected to construct an accident scenario with previously occurring accidents and potential accidents. Through this, we identify the risks of storage facilities at hydrogen refueling stations and suggest measures to improve the safety of hydrogen charging stations.

• Journal of the Society of Naval Architects of Korea
• /
• v.59 no.3
• /
• pp.164-172
• /
• 2022

A HAZID is a brainstorming workshop to identify hazards in an early phase of a project. It should be flexible to capture all probable accidents allowing experienced participants to exploit their expertise and experiences. A bowtie analysis is a graphical representation of major accident hazards elaborating safety measures i.e. barriers. The result of these workshops should be documented in an organized manner to share as good as possible details of the discussion through the lifetime of the project. Currently results are documented using a three-step representation of an accident; causes, top event and consequences, which cannot capture correctly sequence of events leading to various accidents and roles of barrier between two events. Another problem is that barriers would be shown repeatedly leading to a misunderstanding that there are an enough number of safety measures. A new bowtie analysis method is proposed to describe an accident in multiple steps showing relations among causes or consequences. With causes and consequences shown in a format of a tree, the frequencies of having the top event (Fault tree analysis) and various consequences (Event tree analysis) are evaluated automatically based on the frequency of initiating causes and the probabilities of failure of barriers. It will provide a good description of the accident scenario and help the risk to be assessed transparently.

• Fire Science and Engineering
• /
• v.34 no.2
• /
• pp.72-85
• /
• 2020

This article is a study on the activity of rescue workers for designing simulation training scenarios assuming chemical accidents. On the basis of the complexity of the indoor scene in the case of chemical accidents and terrorism, we designed a 12-step simulation training scenario for two teams to analyze the improvement in firefighters' capabilities. On the basis of activity measurement in the simulation scenario, step 2 of training had the most drops in the maximum heart rate, as follow: N1, from 163 bpm to 153 bpm; N2, from 186 bpm to 151 bpm; N3, from 168 bpm to 162 bpm; and N4, from 166 bpm to 152 bpm. In terms of intensity level in the allowable activity time, it was found that in step 2 both N1 and N2 reduced from Level 5 to Level 3, N3 remained at Level 4, N4 reduced from Level 4 to Level 3, and the maximum allowable activity time increased.

• Korean Journal of Construction Engineering and Management
• /
• v.17 no.3
• /
• pp.43-51
• /
• 2016

Recently, the cost of construction projects has escalated due to a significant increase in size and complexity. Many construction projects have failed to meet their originally intended project deadline due to various factors such as weather, labor supply, equipment, procurement, accidents, etc. Consequently, emergency construction work scenario has to be implemented in order to shorten the duration and satisfy the original estimated schedule. However, many critical decisions in emergency scenario rely solely on the experience of a construction manager. Thus, this paper proposes TCTO optimization model to decide the most effective alternative out of various working scenarios which are generated by the combination of work group and work time. The developed TCTO model provides the optimum schedule that satisfies the practical constraints. Future research could involve the integration of resource leveling with the proposed model. This would make the model more versatile.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.9
• /
• pp.1019-1027
• /
• 2014

Vehicle-into-pedestrian traffic accidents show a very high mortality rate compared to their frequency of occurrence. Throughout the world, governments and insurance companies tend to establish and implement new safety standards for pedestrian protection. In order to improve the performance of pedestrian protection, the Korean government has evaluated the pedestrian safety of vehicles under the Korea New Car Assessment Program (K-NCAP) since 2007. The pedestrian protection performance has improved gradually, but it remains insufficient. A pedestrian protection system consisting of a hood lift system and a pedestrian airbag can be a solution to pedestrian safety. A pedestrian airbag design procedure based on a newly defined design scenario is introduced to reduce the head injury criterion of pedestrians. The proposed design scenario is discussed from a practical viewpoint and applied to manufacture pedestrian protection systems.

• Nuclear Engineering and Technology
• /
• v.49 no.2
• /
• pp.411-425
• /
• 2017

Using a probabilistic safety assessment, a risk evaluation framework for an aircraft crash into an interim spent fuel storage facility is presented. Damage evaluation of a detailed generic cask model in a simplified building structure under an aircraft impact is discussed through a numerical structural analysis and an analytical fragility assessment. Sequences of the impact scenario are shown in a developed event tree, with uncertainties considered in the impact analysis and failure probabilities calculated. To evaluate the influence of parameters relevant to design safety, risks are estimated for three specification levels of cask and storage facility structures. The proposed assessment procedure includes the determination of the loading parameters, reference impact scenario, structural response analyses of facility walls, cask containment, and fuel assemblies, and a radiological consequence analysis with dose-risk estimation. The risk results for the proposed scenario in this study are expected to be small relative to those of design basis accidents for best-estimated conservative values. The importance of this framework is seen in its flexibility to evaluate the capability of the facility to withstand an aircraft impact and in its ability to anticipate potential realistic risks; the framework also provides insight into epistemic uncertainty in the available data and into the sensitivity of the design parameters for future research.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.30 no.5
• /
• pp.957-966
• /
• 2020

According to the recent statistics of the National Industrial Security Center, about 80% of the confidential leak are caused by former and current employees in the case of domestic confidential leak accidents. Most of the information leak incidents by these insiders are due to poor security management system and information leak detection technology. Blocking confidential leak of insiders is a very important issue in the corporate security sector, but many previous researches have focused on responding to intrusions by external threats rather than by insider threats. Therefore, in this research, we design an internal information leak scenario to effectively and efficiently detect various abnormalities occurring in the enterprise, analyze the key indicators of the leak symptoms derived from the scenarios by using data analytics and propose a model that accurately detects leak activities.

• Journal of the Korean Institute of Gas
• /
• v.27 no.1
• /
• pp.13-22
• /
• 2023

As an alternative to environmental pollution generated from fossil fuels currently in use, research is being actively conducted to use hydrogen that does not cause air pollution. As fire and explosion accidents caused by hydrogen leakage have occurred until recently, research on safety is needed to commercialize hydrogen on ships, which are special environments. In this study, a seasonal alternative scenario for each season and the worst scenario were assumed in the event of a leakage accident while a hydrogen fuel cell propulsion ship equipped with a hydrogen storage tank was navigating at JangSaengPo port in Ulsan. In order to consider environmental variables, the damage impact range was derived through ALOHA and probit analysis based on the annual average weather data for 2021 by the Korea Meteorological Administration and on geographic information data from the National Statistical Office. Radiation showed a wider damage range than that of Overpressure and Flame in both the alternative and worst-case scenarios, and as a result of probit analysis, a fatality rate of 99% was confirmed in all areas.

• Nuclear Engineering and Technology
• /
• v.55 no.3
• /
• pp.999-1008
• /
• 2023

Deformed fuel rods can cause a partial blockage of the flow area in a subchannel. Such flow blockage will influence the core coolant flow and further the core heat transfer during the reflooding phase and subsequent severe accidents. Nevertheless, most of the system analysis codes simulate the accident process based on the assumed flow blockage ratio, resulting in inconsistencies between simulated results and actual conditions. This paper aims to study the influence of flow blockage in severe accident scenario of the CAP1400 reactor. First, the flow blockage model of ISAA code is improved based on the FRTMB module. Then, the ISAA-FRTMB coupling system is adopted to model and calculate the QUENCH-LOCA-0 experiment. The correctness and validity of the flow blockage model are verified by comparing the peak cladding temperature. Finally, the DVI Line-SBLOCA accident is induced to analyze the influence of flow blockage on subsequent CAP1400 reactor core heat transfer and core degradation. From the results of the DVI Line-SBLOCA accident analysis, it can be concluded that the blockage ratio is in the range of 40%-60%, and the position of severe blockage is the same as that of cladding rupture. The blockage reduces the circulation area of the core coolant, which in turn impacts the heat exchange between the core and the coolant, leading to the early failure and collapse of some core assemblies and accelerating the core degradation process.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.19 no.2
• /
• pp.145-154
• /
• 2013

HNS, including crude oil and products, shipments have increased. The risk analysis of HNS has assumed the importance, especially in maritime transportation area. There are various forms and kinds of HNS and the consequences of an accident are serious. In order to provide practical measures for preventing accidents, this study analyses the potential risks of HNS on maritime transportation accidents at domestic sea by using Event Tree Analysis. This study carries out risk assessment with F-N curve and risk matrix focusing on liquid cargo carriers (Oil and Products Tanker, Chemical Tanker, LPG/LNG Tanker, etc.). Explosion and sinking, suffocation indicate high consequence when on collision represent high probability. Improving human errors should be the main factor to mitigate risk on human lives.