• Nuclear Engineering and Technology
• /
• 제55권11호
• /
• pp.4125-4133
• /
• 2023

The transportation of spent nuclear fuel is an important process that involves road and sea transport from an interim storage facility to storage and final disposal sites. As spent nuclear fuel poses a significant risk, carefully evaluating its vibration and shock characteristics under normal transport conditions is essential. In this regard, full-scale multi-modal transport tests (MMTT) have been conducted domestically and internationally. In this paper, we discuss the process of developing a multi-body dynamics (MBD) model to analytically simulate conditions that cannot be considered in tests. The MBD model is based on the KORAD-21 transportation system was validated using the Korean MMTT results from 2020 to 2021. This paper summarizes the details of the development and verification of the MBD model for the KORAD-21 transportation system under normal transport test conditions. This approach can be applicable to various transportation scenarios and systems, and the results of this study will help to ensure that nuclear fuel transportation is conducted safely and effectively.

• 방사성폐기물학회지
• /
• 제21권4호
• /
• pp.439-450
• /
• 2023

In this study, the impact load resulting from collision with the fuel rods of surrogate spent nuclear fuel (SNF) assemblies was measured during a rolling test based on an analysis of the data from surrogate SNF-loaded sea transportation tests. Unfortunately, during the sea transportation tests, excessive rolling motion occurred on the ship during the test, causing the assemblies to slip and collide with the canister. Hence, we designed and conducted a separate test to simulate rolling in sea transportation to determine whether such impact loads can occur under normal conditions of SNF transport, with the test conditions for the fuel assembly to slide within the basket experimentally determined. Rolling tests were conducted while varying the rolling angle and frequency to determine the angles and frequencies at which the assemblies experienced slippage. The test results show that slippage of SNF assemblies can occur at angles of approximately 14° or greater because of rolling motion, which can generate impact loads. However, this result exceeds the conditions under which a vessel can depart for coastal navigation, thus deviating from the normal conditions required for SNF transport. Consequently, it is not necessary to consider such loads when evaluating the integrity of SNFs under normal transportation conditions.

• 대한교통학회지
• /
• 제30권2호
• /
• pp.117-126
• /
• 2012

교통부문에서 발생되는 $CO_2$ 배출량이 전체 $CO_2$ 배출 총량의 33%를 차지하고 있는 상황에서 지구 온난화를 방지할 수 있도록 교통부문 온실가스 저감 대책을 마련하는 것은 매우 중요하다. 효과적인 교통부문 온실가스 저감대책을 수립하기 위하여 자동차의 오염물질 배출량을 객관적이고 정확하게 산출할 수 있는 방법론 개발이 선행되어야 하지만, 현재까지 표준화된 교통부문 오염물질 배출량 산출 방법론이 정립되어 있지 못한 실정이다. 세계적으로 가장 널리 사용되고 있는 평균 차속 모형은 빠르고 간편하게 대기오염 영향을 산출할 수 있다는 장점을 갖지만, 다양한 도로조건과 교통조건을 반영하지 못하는 한계가 있다. 본 논문에서는 현행 평균 차속 모형을 통하여 산출된 배출량이 주행 여건에 따라 현실에서 발생하는 배출량과 많은 차이가 있음을 실제 데이터 분석을 통하여 확인하였으며, 향후에는 평균 차속 모형의 배출계수가 도로 유형과 교통 상황에 따라 구분될 필요가 있음을 제기하였다.

• Nuclear Engineering and Technology
• /
• 제56권2호
• /
• pp.375-388
• /
• 2024

In this study, to evaluate the shock and vibration load characteristics of used fuel, a sea transportation test was conducted using simulated fuel assemblies under normal transport conditions. An overall test data analysis was performed based on the measured strain and acceleration data obtained from cruise, rotation, acceleration, braking, depth of water, and rolling tests. In addition, shock response spectrum and power spectral densities were obtained for each test case. Amplification and attenuation characteristics were investigated based on the load path. The load was amplified as it passed from the overpack to the simulated used fuel-assembly. As a result of the RMS trend analysis, the fuel-loading position of the transportation package affected the measured strain in the fuel rod, and the maximum strains were obtained at the spans with large spacing. However, even these maximum strains were very small compared to the fatigue strength and the cladding yield strength. Moreover, the fuel rods located on the side exhibited a larger strain value than those at the center.

• 교통기술과정책
• /
• 제13권1호
• /
• pp.23-30
• /
• 2016

• 대한교통학회지
• /
• 제3권1호
• /
• pp.76-85
• /
• 1985

The significant role of transportation system for economic development process has been recognized, but the argument that transportation improvements stimulate economic development has brought sometimes no resonance in lacking of a plausible theory on the conditions and process of economic development by transportation investment. This paper reviews the theory on regional differentiation of transportation system and shows why and how the installation of a new transportation system or the improvements of the old transportation quality differentiate the spatial order of economic activities. It presents the interaction between the change of transportation quality with introducing of definition "transportation value" as tool of its determination and economic activities following the regional differentiation process, which result means regional defferentiation of niveau of economic development.

• 한국자동차공학회논문집
• /
• 제22권1호
• /
• pp.148-156
• /
• 2014

The objective of this study is to compare NOx emissions from light duty diesel vehicles measured from on-road tests that conducted under various driving routes and seasonal conditions. We measured real-driving NOx emissions using PEMS, portable emissions measurement system, under the urban, rural and motorway road traffic conditions. On-road tests were repeated at summer, fall and winter season. The accumulated driving distance is more than 1,200 km per each vehicle. Route average NOx emission factors were compared among nine route-season combinations. The emission characteristics of each combinations were investigated using time series mass emission rates and vehicle operation-based emission rates and activities, which is based on U.S. EPA's MOVES model. Most concerned route-season combination is "urban road condition at summer", which shows two to eleven times higher NOx emissions than other combinations. The emission rates and activities under low speed operating conditions should be managed in order to reduce urban-summer NOx. From a NOx control strategy perspective, the exhaust gas recirculation, EGR, is observed to be properly operated under wide range of vehicle driving conditions in Euro-5 vehicles, even if the air conditioner turns on. In high power demanding conditions, the effect of overspeeding could be more critical than that of air conditioner activation.

• 대한토목학회논문집
• /
• 제32권1D호
• /
• pp.23-31
• /
• 2012

부산광역시는 2007년부터 시내버스 준공영제를 시행하고 있으며 급격히 증가하고 있는 재정지원금이 큰 문제로 대두되었다. 현재 부산시의 재정 상태를 감안한 경우 시내버스 준공영제의 성공 여부는 매년 투입되어야 하는 재정지원금을 연차적으로 감소시켜 나가야 하는 부분이다. 부산시 재정부담을 완화하기 위해서는 시내버스 이용을 보다 편리하게 하여 버스 이용객의 수요를 지속적으로 증가시켜야 할 것이다. 교통수요에 영향을 미치는 기상조건을 살펴보면 눈, 안개, 비 등이 있으며 이러한 기상조건은 통행자들의 수단선택에 영향을 미쳐 결과적으로 버스 이용의 감소를 가져온다. 그리하여 기상 악화시 이용률 저하는 수익금 감소로 이어지게 되어 부산시의 막대한 공공재정 부담으로 돌아오게 된다. 본 연구에서는 기상 상태에 따른 교통수단간 수송 분담률을 파악하여 기상 악화시 버스 승객이 타 교통수단으로 전환하는 패턴을 분석하고 설문조사를 통해 타 수단으로 전환하는 이유를 분석함으로써 향후 대중교통시설 및 환승체계 구축 등 버스정책 수립에 필요한 정책적 시사점을 도출하는데 목적이 있다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제26권6호
• /
• pp.874-878
• /
• 2013

Unlike Europe (particularly, Italy and Spain), where a number of studies have been conducted on the stressful effects of transport on rabbit welfare, few studies have been conducted on transportation of rabbits under hot, humid tropical conditions experienced in countries like Malaysia. We studied the effects of transportation in hot humid tropical conditions of Malaysia on physiometabolic changes in New Zealand white rabbits. Eighty experimental animals were divided into two groups of 40 bucks each and transported for either 3 or 1 h. Transportation caused a significant upsurge of aspartate aminotransferase, alanine aminotransferase and creatine kinase activities (p<0.001) though did not significantly affect lactate dehydrogenase (LDH) activity (p = 0.0706). Both transportation periods caused elevation in plasma glucose levels, lactic acidosis and dehydration as evidenced through elevated packed cell volume and plasma protein concentration. It was concluded that regardless of the duration, transport of rabbits under hot humid tropical conditions, resulted in heat distress since the rabbits showed hyperglycemia, hypercalcemia, lactacidemia, lymphocytopenia, dehydration and increase in blood enzyme activities.

• 한국대기환경학회지
• /
• 제29권6호
• /
• pp.745-756
• /
• 2013

The purpose of this study is to evaluate representativeness of fuel-based emission factors. Twelve light-duty diesel vehicles which meet Euro-3 to 5 legislative emission limits were selected for emission tests. Second-by-second modal emission rates of vehicles were measured on a standard laboratory chassis dynamometer system. An off-cycle driving cycle was developed as a representative Korean real-world on-road driving cycle. Fuel-based emission factors were developed for short trip segments that involved in the selected driving cycle. Each segment was defined to have unit travel distance, which is 1 km, and characterized by its average speed and Relative Positive Acceleration (RPA). Fuel-based $NO_x$ emission factors demonstrate relatively good representativeness in terms of vehicle operation conditions. $NO_x$ emission factors are estimated to be within ${\pm}20%$ of area-wide emission factor under more than 40% of total driving situations. This result implies that the fuel-based $NO_x$ emission factor could be practically implemented into the on-road emission management strategies, such as a remote sensing device (RSD). High emitting vehicles as well as high emitting operating conditions heavily affect on the mean values and distributions of CO and THC emission factors. Few high emitting conditions are pulling up the mean value and biasing the distributions, which weaken representativeness of fuel-based CO and THC emission factors.