• 한국안전학회지
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• 제32권5호
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• pp.1-7
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• 2017

Forensic Engineering is the art and science of professionals qualified to serve as engineering experts in courts of law or in arbitration proceedings. Buses using compressed natural gas (CNG) trend to be extended in use internationally as optimal counterplan for reducing discharge gas of light oil due to high concern about environment. However, CNG buses is equipped with composite pressure vessels (CPVs); since the CPVs contain compressed natural gas, the risks in the case of accident is very high. In this study, the bursting test for the pressure vessel depending on the heat treatment conditions of the vessel in which the actual ruptured accident occurred, after the bursting test, the fracture pattern analysis had performed. The mechanical materials properties test using Instrumented Indentation Test had performed to confirm the mechanical properties for each heat treatment cases. Also, the fractography analysis and metallographic analysis had performed to find out the difference of each heat treatment case. By comparing normal vessel with abnormal vessel which have defect of heat treatment conditions in term of the bursting patterns and characteristics of containers using various forensic engineering methods, especially, it is possible to understand how important the heat treatment process is in the high pressure vessel unlike any product.

• 한국안전학회지
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• 제23권5호
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• pp.15-21
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• 2008

The bus using compressed natural gas(CNG) trend to be extended in use internationally as optimal counter-plan for reducing discharge gas of light oil due to high concern about environment. But, Composit pressure vessels(CPV) to be equipped with CNG bus is always involved in the point that safety accidents happen due to having compressed natural gas. In this report, we analysis the cause of CPV bursting accident by reviewing design and manufacture factor and suggest preventive measure through this case.

• Journal of Korean Neurosurgical Society
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• 제37권5호
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• pp.389-391
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• 2005

We report a case of T4 bursting fracture with paraparesis that recovered by posterior approach. A 47-year-old man presented with paraparesis (grade III) which had progressed rapidly after motor cycle accident. After sacrificing the T4 nerve root (right), posterior interbody fusion using cage following T4 corpectomy and T3-4, T4-5 discectomy was performed. After operation, lower extremities motor power improved and he could walk after one month. And this is the first report of posterior approach using cage by corpectomy and two level discectomy in case of upper thoracic burst fracture in Korea.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.474-483
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• 2021

To establish the exclusive role of hydrogen on burst behaviour of Zircaloy-4 during loss-of-coolant accident transients, an extensive single-rod burst tests were conducted on both unirradiated as-received and hydrogenated Zircaloy-4 cladding tubes at different heating rates and internal overpressures. The visual observations of cladding tubes during bursting as well as post-burst are presented in detail to understand the effect of hydrogen concentration, heating rate, and internal pressure. Impact of hydrogen on burst parameters-burst stress, burst strain, burst temperature-during loss-of-coolant accident transients are compared and discussed. Rupture at multiple locations for hydrogenated cladding at lower internal pressure and higher heating rate is reported for the very first time. A novel burst criterion accounting hydrogen concentration in nuclear fuel cladding is proposed.

• 한국안전학회지
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• 제22권5호
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• pp.65-70
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• 2007

This paper is estimation of structure damage caused by VCE(Vapor Cloud Explosion) in enclosure. As we estimate the influence of damage which occur at gas facility in factory. We can utilize the elementary data of safety distance. In this study, the influence of over-pressure caused by VCE in enclosure was calculated by using the Hopkinson's scaling law and the accident damage was estimated by applying the influence on the adjacent structure into the probit model. As a result of the damage estimation conducted by using the probit model, both the damage possibility of explosion overpressure to structures of 20 meters away and to glass bursting of 80 meters away was nearly zero in open space explosion.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2007년도 춘계학술발표논문집
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• pp.42-45
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• 2007

This paper is estimation of structure damage caused by VCE(Vapor Cloud Explosion) in enclosure. As we estimate the influence of damage which occur at gas facility in factory. We can utilize it the elementary data of safety distance. In this study, the influence of explosion over-pressure caused by VCE in enclosure was calculated by using the Hopkinson's scaling law and the accident damage was estimated by applying the influence on the adjacent structure into the probit model. As a result of the damage estimation conducted by using the probit model, both the damage possibility of explosion overpressure to structures 20 meters away and that of overpressure to glass bursting 80m meters away showed nothing.

• 한국안전학회지
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• 제25권1호
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• pp.44-49
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• 2010

This paper is estimation of structure damage caused by Explosion in LPG(Liquefied Petroleum Gas) filling station. As we estimate the influence of damage which occur at gas storage tank in filling station. We can utilize the elementary data of safety distance. In this study, the influence of over-pressure caused by VCE(Vapor Cloud Explosion) in filling station was calculated by using the Hopkinson's scaling law and the accident damage was estimated by applying the influence on the adjacent structure into the probit model. As a result of the damage estimation conducted by using the probit model, both the damage possibility of explosion overpressure to structures of max 265 meters away and to glass bursting of 1150 meters away was nearly zero in open space explosion.

• 한국가스학회지
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• 제27권3호
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• pp.35-40
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• 2023

과충전, 이상 온도 상승 등 이상 상황이 발생하는 조건에서 암모니아 용기의 파열 사고의 예방을 위해서는 용기에 부착된 가용전식 안전밸브의 작동 메카니즘 분석을 통한 사고 예방대책 마련이 필요하다. 본 연구에서는 가압 조건에서 암모니아 용기에 작용하는 응력 분석, 온도 변화에 따른 밀도 변화 분석, 그리고 용기 충전량과 온도 및 압력 변화에 대한 상관관계를 제시하였다. 또한, 암모니아 용기의 최대 충전량을 계산하고, 상평형 선도를 통해 해당 충전량에서의 온도·압력을 산출했다. 이를 바탕으로 가용전식 안전밸브의 적정 용융점을 도출하고 용융 온도 실험을 통해 이를 검증하였다. 이와 같은 연구 결과를 바탕으로 암모니아 용기 파열 사고의 예방을 위한 조건을 제시하였다.

• Nuclear Engineering and Technology
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• 제48권1호
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• pp.236-245
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• 2016

In a reactor coolant system of a nuclear power plant (NPP), an overpressure protection system keeps pressure in the loop within 110% of design pressure. However if the system does not work properly, pressure in the loop could elevate hugely in a short time. It would be seriously disastrous if a weak point in the pressure boundary component bursts and releases radioactive material within the containment; and it may lead to a leak outside the containment. In this study, a gross deformation that leads to a burst of pressure boundary components was investigated. Major components in the primary pressure boundary that is structurally important were selected based on structural mechanics, then, they were used to study the burst pressure of components by finite element method (FEM) analysis and by number of closed forms of theoretical relations. The burst pressure was also used as a metric of design optimization. It revealed which component was the weakest and which component had the highest margin to bursting failure. This information is valuable in severe accident progression prediction. The burst pressures of APR-1400, AP1000 and VVER-1000 reactor coolant systems were evaluated and compared to give relative margins of safety.

• 한국자기학회지
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• 제15권5호
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• pp.292-297
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• 2005

원자력 발전소 증기발생기의 전열관은 전열면으로서의 역할과 방사능 차단벽의 역할로서 중요하며, 증기발생기 튜브의 폭발은 원자력 발전소 사고에 관계된다. 증기발생기 전열관 재료로는 Incone1600이 사용되고 있으며, 이 재료가 금속이면서 비자성이기 때문에 와전류 탐상법으로 전열관의 결함을 탐지하고 있다. 본 연구에서는 탐상 감도를 향상시키기 위하여 차등형 와전류 탐촉자를 개발하였으며, 개발된 차등형 와전류 탐촉자의 성능검사를 위해 Inconel600과 자기적 성질이 비슷하고 구하기 쉬운 SUS304로 가로 100mm, 세로 100mm, 그리고 두께 10mm인 평판에 선형결함과 원형결함을 가공하여 기준시편으로 제작하였다. 제작된 차등형 와전류 탐촉자를 사용하여, 자화주파수 50kHz, lift-off 0.4mm에서 직경이 0.25mm이고, 깊이가 0.2mm 크기의 결함까지 측정이 가능하였다.