• 방사성폐기물학회지
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• 제21권4호
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• pp.439-450
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• 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.

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

• 한국항만경제학회:학술대회논문집
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• 한국항만경제학회 2007년도 국제학술대회 및 정기총회
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• pp.161-173
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• 2007

This paper considers the problem of determining the cargo flow and the transportation mode in each trade route while satisfying the demand. Especially, the problem incorporates short sea shipping in Korea, which is becoming more important in order to improve efficiency of Logistics. The objective is to minimize the sum of shipping and inland transportation costs. To solve optimally the problem, this paper employs a linear programming model, which is an operations research technique for optimization. The problem is formulated by extending the well-known network design problem by considering capacity at seaport and limitation of total number of vehicles. The model is solved using CPLEX, a commercial linear program software. The test results using a real cargo flow data in Korea show that the model represents closely the real situation.

• 한국해양공학회지
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• 제27권6호
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• pp.112-118
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• 2013

This paper reports the results of a comparative study on rudder performance between the steel rudders that have been used in coastal angling fishing boats in the 20-GT class and the newly developed FRP composite material rudders. In order to compare the rudder performances of these two types, a sea trial test was carried out to investigate the speed performance, fuel consumption, and ship's turning ability. The results showed that the sea trial performance of the FRP composite rudder was better than that of the steel rudder type in terms of the sea speed, fuel consumption rate, and turning ability.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2003년도 추계학술발표회
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• pp.45-51
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• 2003

선박 신호음은 공기, 장애물, 외란 둥에 의해서 흡수, 반사, 방해되어 확산된다. 이 현상은 기적음원의 방향을 오판하여 발생되는 해양사고의 한 가지 원인이 된다. 이 연구의 최종목적은 선박 신호음 간섭을 분석 평가하는 기법을 이용하여 근본적인 해양사고를 예방하는데 있다. 이 논문에서는 해상환경에 따른 다양한 음향 전달특성을 시뮬레이션하기 위한 3차원 음장제어 모델을 제안했다. 그리고, 가상현실 기반 선박 시뮬레이터를 이용하여 모델의 유효성을 평가했다.

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

• 한국항해학회지
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• 제5권1호
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• pp.25-35
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• 1981

Since 1960 tankers and bulk carriers have rapidly increased in size up to 500, 000 dwt. in operating as main system of transportation for the international trade at sea, and studies are doing carried out by various groups with a view to increasing the size still further. However, the service speed of these ships has remained almost constant, and steering devices of them have nearly not changed, comparing with regular size of a dry cargo ship. This creats the dituation where stopping distance and advance are proportionally longer for larger ships. In case of collision at sea, these vessels have been arised some serious casualties, such as sinking, fire and oil pollution. This paper analyzers a study for the handling of super huge vessels to avoid collision at sea, basing on the results of the crash astern test and turning test of them.

• 대한조선학회논문집
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• 제48권1호
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• pp.8-14
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• 2011

RIB(Rigid Inflatable Boat) is widely used for coastal transportation in the commercial use and for ISR(Intelligence, Surveillance, Reconnaissance) in the military use. Since RIB is around 10 meters in length and over 30 knots in speed, its motion characteristics in waves is quite different from a large scale ship. When it turns, large roll occurs and heeling direction is opposite to the large ship's case. Currently, many countries are developing USV(Unmanned Surface Vehicle) of which type is RIB. In order to develop high performance autopilot and way point controller, it is very important to identify RIB's motion characteristics. In this paper, sea trial test results of a 7-meter RIB such as speed, turning, zig-zag, and way point control tests were represented and its resistance and propulsion model was identified by using sea trial data and Savitsky's formula. In addition, the state space model which will be used in the identification of the four-degree-of-freedom dynamics in the next step was formulated and the identification procedure was proposed.

• 대한조선학회논문집
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• 제45권4호
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• pp.396-402
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• 2008

As demands for high speed sea transportations have recently been increased, various high speed ships appear. Among them the WIG is believed to be one of the next generation of the sea transportation system. Test flight of the 20 seaters WIG craft, Haenarae-X1, developed by MOERI was a success in August, 2007. Development of the large WIG is now ongoing, and it is expected to be commercialized in the near future. In this study we designed a remote controled WIG Craft and carried out its performance test in order to establish engineering design procedures of an Unmanned WIG (U-WIG) craft.

• 대한조선학회논문집
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• 제42권2호
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• pp.105-112
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• 2005

IMO standards for ship manoeuvrability were applied from January 1, 2004. Though model test or sea trial in full load condition is needed, it is not always possible to get such data for every ships. Therefore it is required to study the effect of loading conditions on ship manoeuvrability. Approximate formulae to estimate the hydrodynamic forces acting on a ship and the 2nd overshoot angle of $10^{\circ}$/$10^{\circ}$ zig-zag test in certain loading condition are proposed in this study These were derived from the results of model test and sea trial data. Captive model tests for 7 ships with 15 different loading conditions and sea trial data including free running test of 6 cases were used. Compared with experiment data and prediction formulae already proposed by others, the approximate formulae in this study show good agreement with model test results.