PURPOSES : This study analyzes the accident damage scale of hazardous material transportation vehicles not monitored in real time by the Hazardous Material Transportation Safety (HMTS) management center. METHODS : To simulate hazardous-material transportation vehicle accidents, a preliminary analysis of transportation vehicle registration status was conducted. Simulation analyses were conducted for hazardous substance and flammable gas transportation vehicles with a high proportion of small- and medium-sized vehicles. To perform a spill accident damage-scale simulation of hazardous-substance transportation vehicles, the fluid analysis software ANSYS Fluent was used. Additionally, to analyze explosion accidents in combustible gas transportation vehicles, the risk assessment software Phast and Aloha were utilized. RESULT : Simulation analysis of hazardous material transportation vehicles revealed varying damage scales based on vehicle capacity. Simulation analysis of spillage accidents showed that the first arrival time at the side gutter was similar for various vehicle capacities. However, the results of the cumulative pollution analysis based on vehicle capacity exhibited some differences. In addition, the simulation analysis of the explosion overpressure and radiant heat intensity of the combustible gas transportation vehicle showed that the difference in the danger radius owing to the difference in vehicle capacity was insignificant. CONCLUSIONS : The simulation analysis of hazardous-material transportation vehicles indicated that accidents involving small- and medium-sized transportation vehicles could result in substantial damage to humans and ecosystems. For safety management of these small and medium-sized hazardous material transportation vehicles, it is expected that damage can be minimized with the help of rapid accident response through real-time vehicle control operated by the existing HMTS management center.

The delivery truck is traveled around the delivery area for a long time. Truck drivers cause traffic accidents because of long hours of driving, fatigue, and speeding, etc. In this study, we will test the factors for preventing accidents of drivers. We would like to find factors that affect accidents and improve that can prevent accidents. As in the results of the study, accidents occur when traffic increases and profits increase among driver age, career, and profit factors. In addition, if the volume of traffic increases during the season, the number of accidents increases further. Therefore, in order to prevent truck accidents, a stable cargo quantity must be allocated to truck and cargo must be delivered.

유류를 포함한 위험 유해물질(Hazardous and Noxious Substances : HNS, 이하 HNS)의 물동량이 증가하는 추세에 있음에도 불구하고 우리나라에서는 HNS 해상운송 중에 일어난 사고의 분석과 위험에 관한 연구가 미진하다. HNS는 형태와 종류가 다양하고, 사고발생 시 피해가 심각하게 나타나기 때문에 사고에 대한 위험도 분석과 저감방안 모색이 필요하다. 본 연구는 ETA를 통해 국내에서 발생하고 있는 HNS 해상운송사고의 전개과정을 분석하여 사고유형과 특징을 고찰하고, 시나리오별 확률과 인명피해를 산출하여 F-N curve로 표현함으로써 위험도를 평가한다. 또한 Risk Matrix를 이용하여 고위험군 시나리오를 선정하여 국내에 적용 가능한 현실적인 사고 저감방안을 모색한다. 연구의 결과는 충돌사고의 발생확률이 가장 높은 반면 인명위험도는 발생확률이 낮은 질식, 침몰, 폭발의 사고유형이 높은 것으로 나타났다. 이러한 인명피해를 줄이기 위해서는 기본적으로 선내에서 안전수칙 및 작업절차를 준수하는 것으로도 효과를 얻을 수 있다.

유류를 포함한 HNS의 물동량이 증가 추세에 있음에도 불구하고, 우리나라에서는 HNS 해상운송 중에 발생한 사고의 분석과 위험에 관한 연구가 미진하다. HNS는 형태와 종류가 다양하고 사고발생시 피해가 심각하게 나타난다. 액체화물운반선(유조선, 케미컬탱커선, 액화가스탱커선 등)의 사고에 대한 원인을 분석하고 위험성에 대한 연구가 필요하다.

Integrity evaluation scheme for Spent Fuel (SF) dry storage has been developed under transportation failure modes. This method especially considered the degradation characteristics of Spent Fuel (SF) during dry storage such as radial and circumferential hydride content, hydride volume fraction, oxide thickness, etc. Hydride and zircaloy cladding are considered as material composite system, using correlation models related to material properties. Critical Strain Energy Density (CSED) is compared with Strain Energy Density (SED), to evaluate cladding integrity. CSED serves as material characteristics, while SED can be considered as boundary condition. To calculate the CSED of cladding in the lateral failure mode, circumferential hydride concentration is used. SED is calculated considering both the bending moment and axial load. On the other hand, in the longitudinal failure case, fuel rod temperature, internal pressure, hoop stress, radial hydride concentration is used to calculate CSED. And pinch force (contact) was considered to evaluate SED. Model validations were conducted by comparing hot cell SF test and existing validated evaluation results. To separately handle normal transportation conditions from hypothetical accident conditions, SED according to stress-strain analysis results was separated into elastic and plastic regions. As a result of applying this scheme for 14×14 SF, failure probability of normal condition was zero, which is the similar result with DOE and same with EPRI. Regarding accident condition, lateral case showed similar result, but longitudinal case showed different but reasonable result, which was due to the different analysis conditions. The proposed methodology which was indigenously developed through this study is named as K-method.

Currently, low and intermediate-level radioactive wastes and spent nuclear fuels are continuously generated in Korea. For the disposal of the radioactive wastes, the transport demand is expected to increase. Prior to transportation, it is necessary to evaluate the radiation risk of transportation to confirm that is not high. In Korea, there is no transportation risk assessment code that reflects domestic characteristics. Therefore, foreign assessment codes are used. In this study, before developing the overland transportation risk assessment code that reflects domestic characteristics, we analyzed the radiation risk assessment methodology in transportation accident codes developed in other countries. RADTRAN and RISKIND codes were selected as representative overland transportation risk assessment codes. For the two codes we analyzed accident scenarios, exposure pathways, and atmospheric diffusion. In RADTRAN, the user classifies accident severity for possible accident scenarios, and the user inputs the probability for each accident severity. On the other hand, in the case of RISKIND, the accident scenarios are classified and the probabilities are determined according to the NRC modal study (LLNL, 1987) in consideration of the cask impact velocity, cask impact angle, and fire temperature. In the case of RISKIND, the accident scenarios are applied only to transportation of spent nuclear fuel, and cannot be defined for low and intermediate-level radioactive waste. However, in the case of RADTRAN, since the severity and probability of accidents are defined by user, it can be applied to low and intermediate-level radioactive wastes. As the exposure pathways considered in transportation accident, both RADTRAN and RISKIND consider external exposure (cloudshine and groundshine), and internal exposure (inhalation, resuspension inhalation and ingestion). In the case of RADTRAN, additionally, external exposure due to loss of shielding (LOS) is considered. Atmospheric diffusion calculation is essential to determine the extent to which radioactive materials are diffused. In both RADTRAN and RISKIND, atmospheric diffusion calculations are based on Gaussian diffusion model. Users must input Pasquill stability class, release height, heat release, wind speed, temperature and mixing height, etc. Additionally, RADTRAN can input weather information relatively simply by inputting only the Pasquill stability class fraction and selecting the US average weather option. This study results will be used as a basis for developing radioactive waste overland transportation risk assessment code that reflects domestic characteristics.

본 논문에서는 상선의 운항 사고에 관한 양적 위기평가에 관한 실험적인 접근방법들을 기술했다. 이 연구의 목적은 국제해사기구의 공식 안전성 평가(FSA)를 기반으로 운항 사고에 크게 기여하는 요소들을 분석하고, 양적 위기평가기법에 기반을 둔 운항 사고의 확률적인 위기수준을 평가한 후, 선박 안전을 저해할 수 있는 운항 사고 위기를 예측하는 것이다. 확률지수(PI)와 심각성지수(SI) 구성된 위기지수(RI)에 대한 운항 사고의 확률적인 위기수준은 베이지안 이론을 적용한 베이지안 네트워크를 기반으로 본 연구에서 제안한 운항사고 위기 모델을 이용해서 예측했다. 그리고 355건의 핵심 손상 사고기록으로 구성된 시나리오 그룹을 이용하여 제안한 모델의 적용 가능성을 평가하였다. 평가결과, 예측한 PI의 정답률 rAcc은 82.8%로 나타났고, Sp》1.0과 Sp《1.0에 포함되는 PI 변수들의 민감도 초과비율은 10% 이내로 나타났으며, 예측한 SI의 평균 오차 dSI는 0.0195로 나타났고, 예측한 RI의 정답률은 91.8%로 나타났다. 이러한 결과는 제안한 모델과 방법이 실제 해상운송 현장에 적용 가능함을 나타낸다.