• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2018년도 추계학술대회
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• pp.241-247
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• 2018

Deep-sea fishing vessel No. 501 Oryong was fully flooded through its openings and sunk to the bottom of the sea due to the very rough sea weather on the way of evasion after a fishing operation in the Bearing Sea. As a result, many crew members died and/or were missing. In this study, a full-scale ship flooding and sinking simulation was conducted, and the sinking process was analyzed for the precise and scientific investigation of the sinking accident using a highly advanced Modeling & Simulation (M&S) system of the Fluid-Structure Interaction (FSI) analysis technique. To objectively secure the weather and sea states during the sinking accident in the Bering Sea, time-based wind and wave simulation at the region of the sinking accident was conducted and analyzed, and the weather and sea states were realized by simulating the irregular strong wave and wind spectrums. Simulation scenarios were developed and full-scale ship and fluid (air & seawater) modeling was performed for the flooding sinking simulation, by investigating the hull form, structural arrangement & weight distribution, and exterior inflow openings and interior flooding paths through its drawings, and by estimating the main tank capacities and their loading status. It was confirmed that the flooding and sinking accident was slightly different from a general capsize and sinking accident according to the simple loss of stability.

• Composites Research
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• 제35권3호
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• pp.161-174
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• 2022

SiC 섬유강화 복합체는 경수형 원자로의 안전성을 획기적으로 향상시킬 수 있는 사고저항성 핵연료 피복관 소재이다. 지르코늄 합금 피복관 및 금속기반 사고저항성 핵연료 피복관에 비해, 중대 사고 환경에서도 우수한 구조적 안정성을 가지고 부식 속도가 매우 낮아, 사고 시 원자로의 온도를 낮추고 사고 진행을 늦출 수 있다. 본 논문에서는 현재 개발되고 있는 사고저항성 SiC 복합체 핵연료 피복관의 개념 및 가동/사고환경에서의 다양한 특성, 상용화를 위해 해결해야 할 다양한 이슈에 대해서 소개하고자 한다.

• 한국산업보건학회지
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• 제33권3호
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• pp.346-354
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• 2023

Objectives: Chemical accidents cause extensive human and environmental damage. Therefore, it is important to prepare measures to prevent their recurrence and minimize future damage through accident investigation. To this end, it is necessary to identify the accident occurrence process and analyze the extent of damage. In this study, the development process and damage range of actual chemical leakage accidents were analyzed using CFD. Methods: For application to actual chemical leakage accidents using FLACS codes specialized for chemical dispersion simulation among CFD codes, release rate calculation and 3D geometry were created, and scenarios for simulation were derived. Results: The development process of the accident and the dispersion behavior of materials were analyzed considering the influencing factors at the time of the accident. In addition, to confirm the validity of the results, we compared the results of the actual damage impact investigation and the simulation analysis results. As a result, both showed similar damage impact ranges. Conclusions: The FLACS code allows the detailed analysis of the simulated dispersion process and concentration of substances similar to real ones. Therefore, it is judged that the analysis method using CFD simulation can be usefully applied as a chemical accident investigation technique.

• 해양환경안전학회지
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• 제20권6호
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• pp.677-684
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• 2014

해양사고 발생시 대응능력 향상을 위해 대응훈련 및 이를 위한 시나리오 개발이 필요하다. 본 연구에서는 위험유해물질 유출사고 대응체계 구축의 일환으로 가상 위험유해물질 유출사고에 대한 대응 시나리오를 개발하였다. 가상 시나리오는 부산 해역을 대상으로 개발하였으며, 대상해역에서 발생될 수 있는 가상 사고 시나리오와 이에 대한 대응 시나리오를 각각 개발하였다. 가상 사고 시나리오는 대상해역인 부산해역의 위험평가 및 취약성분석을 통해 발생될 수 있는 위험유해물질 유출사고를 선정하고, 가상 사고로 인해 발생될 수 있는 피해를 예측하여 구축되었다. 가상 사고에 대한 대응 시나리오는 가상 사고 시나리오의 피해예측에서 제시된 피해를 수습하기 위한 단계별 조치사항으로서 제시하였다. 부산해역의 위험유해물질 가상 유출사고는 부산 감천항 충돌사고로 인한 자일렌(xylene) 1,000톤 유출사고로 선정하였으며, 이로 인한 피해는 자일렌의 대기확산 및 해양확산 계산을 통해 예측하였다. 또한 가상 사고에 대한 대응 시나리오는 피해지역의 주민 대피, 자일렌 확산 방지 및 회수, 대응요원 보호조치, 사고지역 사후 관리 등에 대한 단계별 조치사항을 제시하였다.

• 한국대기환경학회지
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• 제15권2호
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• pp.151-158
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• 1999

Offsite consequences resulting form worst-case scenarios involving release of toxic substances in the Yochon area were estimated using the ALOHA(Areal Locations of Hazardous Atmospheres) model. Eight toxic substances, including NH3, were considered; five were toxic gases and three were toxic liquids at ambient temperature. For toxic gases, the entire quantity was assumed to be released at a constant rate during a 10-minute period. For toxic liquids, the entire quantity stored in the tank was assumed to be spilled and spread and spread instantaneously to form a pool with a depth of 1cm, and then evaporated over some period of time. Except for phosgene and toluene 2,4-diisocyanate, for which concentration levels corresponding to human health effects are very low, average distances of the area at risk of adverse health effects for a 1- tom release were predicted to be $2.3{\pm}1.1 km$ for the worst-case meteorological conditions and $0.93{\pm}0.69km$ under typical meteorological conditions of the Yochon are. Because a large number of people were predicted to be affected in the current analysis, refined analyses considering both realistic accident scenarios and topographic effects were warranted.

• Nuclear Engineering and Technology
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• 제33권5호
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• pp.468-482
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• 2001

As a process of Direct Containment Heating (DCH) issue resolution for Korean Standard Nuclear Power Plants (KSNPs), a containment load/strength assessment with two different approaches, the probabilistic and the deterministic, was performed with all plant-specific and phenomena-specific data. In case of the probabilistic approach, the framework developed to support the Zion DCH study, Two-Cell Equilibrium (TCE) coupled with Latin Hypercubic Sampling (LHS), provided a very efficient tool to resolve DCH issue. In case of the deterministic approach, the evaluation methodology using the sophisticated mechanistic computer code, CONTAIN 2.0 was developed, based on findings from DCH-related experiments or analyses. For three bounding scenarios designated as Scenarios V, Va, and VI, the calculation results of TCE/LHS and CONTAIN 2.0 with the conservatism or typical estimation for uncertain parameters, showed that the containment failure resulted from DCH loads was not likely to occur. To verify that these two approaches might be conservative , the containment loads resulting from typical high-pressure accident scenarios (SBO and SBLOCA) for KSNPs were also predicted. The CONTAIN 2.0 calculations with boundary and initial conditions from the MAAP4 predictions, including the sensitivity calculations for DCH phenomenological parameters, have confirmed that the predicted containment pressure and temperature were much below those from these two approaches, and, therefore, DCH issue for KSNPS might be not a problem.

• 한국안전학회지
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• 제31권3호
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• pp.156-161
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• 2016

An accident of an ammonia tank pipeline at a storage plant resulted in one death and three injuries in 2014. Many accidents including toxic gas releases and explosions occur in the freezing and refrigerating systems using ammonia. Especially, the consequence can be substantial due to that the large amount of ammonia is usually being used in the refrigeration systems. In this study, offsite consequence analysis has been investigated when ammonia leaks outdoors from large storages. Both flammable and toxic effects are under consideration to calculate the affected area using simulation programs for consequence analysis. ERPG-2 concentration (150 ppm) has been selected to calculate the evacuation distance out of various release scenarios for their dispersions in day or night. For offsite residential, the impact area by flammability is much smaller than that by toxicity. The methodology consists of two steps as followings; 1. Calculation for discharge rates of accidental release scenarios. 2. Dispersion simulation using the discharge rate for different conditions. This proactive prediction for accidental releases of ammonia would help emergency teams act as quick as they can.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.318-321
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• 2005

Crashworthy design of a train is a systematic approach to ensure the safety of passengers and crews in railway transportation for the prescribed accident scenarios. This approach needs new structural arrangements and designs to absorb higher levels of impact energy in a controlled manner and interior designs to minimize passenger injuries. In this paper, an evaluation method for crashworthiness of Korean tilting train express is introduced. Crush characteristics for each part of tilting train express are evaluated numerically through 3-dimensional shell element analysis with LS-DYNA. Based on a head-on collision and a level crossing collision scenarios, the crash behaviors of tilting train express are evaluated numerically using full-rake collision simulations.

• 한국산업안전학회:학술대회논문집
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• 한국안전학회 2000년도 춘계 학술논문발표회 논문집
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• pp.196-196
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• 2000

This paper presents an approach for modeling of the generation of a set of credible accident scenarios for a petrochemical plant, which will be used to perform quantitative hazard assessments such as the consequence assessment, FTA or ETA. This approach is carried out in ways of identifying, classifying a set of major components and elements for scenarios generation by analysis of the informations on various actual accidents, and thus setting priorities of both factors of likelihood and consequence on each component or element identified.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.646-651
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• 2004

Crashworthy design of a train is a systematic approach to ensure the safety of passengers and crews in railway transportation for the prescribed accident scenarios. This approach needs new structural arrangements and designs to absorb higher levels of impact energy in a controlled manner and interior designs to minimize passenger injuries. In this paper, crashworthy design approach is applied to the tilting train express (TIX) design which is newly being developed. Based on a head-on collision and a level crossing collision scenarios, the crash behaviors of a TTX design candidate arc evaluated numerically using the finite element method. Finally, design alternatives which show better crashworthy performances are proposed and verified through the full-rake collision simulations.