• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1174-1183
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• 2016

Hydrogen release during severe accidents poses a serious threat to containment integrity. Mitigating procedures are necessary to prevent global or local explosions, especially in large steel shell containments. The management of hydrogen safety and prevention of over-pressurization could be implemented through a hydrogen reduction system and spray system. During the course of the hypothetical large break loss-of-coolant accident in a nuclear power plant, hydrogen is generated by a reaction between steam and the fuel-cladding inside the reactor pressure vessel and also core concrete interaction after ejection of melt into the cavity. The MELCOR 1.8.6 was used to assess core degradation and containment behavior during the large break loss-of-coolant accident without the actuation of the safety injection system except for accumulators in Beznau nuclear power plant. Also, hydrogen distribution in containment and performance of hydrogen reduction system were investigated.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.3
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• pp.278-286
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• 2019

The Port of Pyeong Taek is located on the west coast, meaning that the difference between the rise and fall of tide is great (flood tide 1.8 to 2.9 knots, ebb tide 1.6 to 2.9 knots). Due to mainly N~NW'ly strong winds & high waves during winter, navigating as well as loading & discharging vessels must focus on cargo handling. The strong tidal and wind forces in the Port of Pyeong Taek can push an LNG carrier away from its berth, which will end up causing forced disconnection between the vessel's cargo line and shore-side loading arm. The primary consequence of this disconnection will be LNG leakage, which will lead to tremendous physical damage to the hull and shore-side equipment. In this study, the 125K LNG Moss Type ship docked at No. 1 Pier of the Pyeong Taek is observed, and the tension of the mooring line during cargo handling is calculated using a combination of wind and waves to determine effective mooring line and mooring line priority management. As a result if the wind direction is $90^{\circ}$ to the left and right of the bow, it was found that line monitoring should be performed bearing special attention to the Fore Spring Line, Fore Breast Line, and Aft Spring Line.

• Journal of Navigation and Port Research
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• v.33 no.6
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• pp.423-428
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• 2009

Recently, the marine traffics have been increased along with enlargement of overseas commerce. Increasing the marine traffic may make higher the risk of marine accidents. Especially, the rate of accidents on costal area are more frequently. As if the marine safety information can be afforded to vessel and shore, the accident rate would be down. AIS AtoN is the navigational safety support device which is subject to functional requirements of IALA and technical standards of ITU. In this paper, we extend and implement the user-defined specification of AIS AtoN with message 21 for AIS basic information, messsage 6 for status report and message 12/14 for safety management.

• Journal of the Korean Society of Safety
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• v.33 no.6
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• pp.15-21
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• 2018

Ships may collide with reefs or other objects during operation, when arriving or departing ports. The hull plate may be damaged due to the contact with other ships. The total number of domestic powered fishing vessels has decreased, but that of FRP fishing vessels has increased by 0.7% and the ratio of FRP fishing vessels to the total fishing vessels increased to 96%. Recently, fishing vessels has been used as fishing boats for income of non-fishermen as well as fishermen. Therefore, safety management for repair and maintenance is necessary. The penetration of moisture and moisture in the composite material such as FRP may deteriorate the mechanical properties and the salt (NaCl) component of the damaged portion may cause a relatively high deterioration in material strength. The gel coat painting is the final stage of repairs ans maintenance of FRP fishing vessels. The thickness criteria in the domestic and foreign gel coat is 0.3~0.762 mm. The joint specimens, which was immersed in seawater for 120 days, were compared with those without seawater immersion. As a result, the tensile strength was 83 ~ 121.8% and the flexural strength was 83 ~ 113% compared with the specimens without seawater immersion. According to the previous study the tensile strength decreased by more than 29% and the flexural strength decreased by more than 50% when the composite material was immersed in seawater for 1,083 hours without coating. As a result, it was found that the gel coat with 0.5 mm thickness is very effective in preventing the strength decrease of the composite material.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2002-2010
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• 2024

Korea Atomic Energy Research Institute (KAERI) has operated an integral effect test facility, the Advanced Thermal-Hydraulic Test Loop for Accident Simulation (ATLAS), with reference to the APR1400 (Advanced Power Reactor 1400) for tests for transient and design basis accidents simulation. A test for a loss of coolant accident (LOCA) at the top of the reactor pressure vessel (RPV) had been conducted at ATLAS to address the impact of the loss of safety injections (LSI) and to evaluate accident management (AM) actions during the postulated accident. The experimental data has been utilized to validate system analysis codes within a framework of the domestic standard problem program organized by KAERI in collaboration with Korea Institute of Nuclear Safety. In this study, the test has been analyzed by using thermal-hydraulic system analysis codes, MARS-KS 1.5 and TRACE 5.0 Patch 6, and a comparative analysis with experimental and calculation results has been performed. The main objective of this study is the investigation of the thermal-hydraulic phenomena during a small break LOCA at the RPV upper head with the LSI as well as the predictability of the system analysis codes after the AM actions during the test. The results from both codes reveal that overall physical behaviors during the accident are predicted by the codes, appropriately, including the excursion of the peak cladding temperature because of the LSI. It is also confirmed that the core integrity is maintained with the proposed AM action. Considering the break location, a sensitivity analysis for the nodalization of the upper head has been conducted. The sensitivity analysis indicates that the nodalization gave a significant impact on the analysis result. The result emphasizes the importance of the nodalization which should be performed with a consideration of the physical phenomena occurs during the transient.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.2
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• pp.153-159
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• 2016

Gwangyang traffic safety designated area is composed of 3 fairways (Deep water fairway, inbound fairway, and outbound fairway). However, inbound vessels can't use this passage because of Samyeo rock and artificial fishing banks in inbound route. The problem with the rocks and artificial fishing banks has been raised by ship navigators and authorities of the port. This research is about the safety evaluation and management plan of the passage, and we conducted maritime traffic simulation using a model based on a ship operator risks. As a result, assuming that future marine traffic volume is the same as the present, and if the ship operators use 3 fairways and not two, it showed risk reduction of 46.4 % (vessels over 50,000 DWT using DW route) and 57.1 % (vessels over 10,000 DWT using DW route). Also, in a traffic volume condition which is the same as the present, to induce vessels over 50,000 DWT to use DW route is effective in mitigating of risks. Meanwhile, in a condition which increased the traffic volume by 150 %, it is more effective to induce vessels to use DW route. This research is the result of analysis using the model based on ship operator risks, and not cost-effectiveness analysis on the removal of Samyeo rock and artifical fishing banks. This research is expected to be used on setting up the sea route and management plan (particularly, restriction on passing DW route).

• The Journal of Fisheries Business Administration
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• v.31 no.1
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• pp.73-93
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• 2000

This study analyzed and mutually compared the fishery manpower problems in Northeast Asia region including Korea, China, Japan by fishery industry structure, fishery education, fishery manpower and presented fishery cooperative schemes of Northeast Asia. In case of fishery manpower problems, China is still in a better situation whereas Korea and Japan have a hard time of a labor shortage. Korean companies have employed foreign crews to find a way out of the difficulties and the foreign crew rate is growing but the problem is that the reduction of Korean crew could deteriorate the safety of vessel-sailing, efficient operations, and fishery efficiency. Therefore crew management should be placed focus on improvement of working conditions and guarantee positions to foreign crew as assistants in fishery surroundings and systems. Fishery manpower problems are complementary to each nation in Northeast Asia. In consideration of this fact, fishery manpower management needs the mutual fishery manpower and information exchange and for the sake of it, the most urgent task is to build up the international fishery cooperative network through establishing fishery-related information systems of Northeast Asia.

• Journal of the Korean Institute of Navigation
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• v.22 no.1
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• pp.63-77
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• 1998

It is one of the most important factors Seafarers Ducation Quality Assurance and Management in Higher Maritime Educational Institution. The educational process and result of Higher Maritime Educational Institution should be evaluated according to the 1995 Amendments to the International Convention on Standards of Training, Certification and Watchkeeping for Seafarers(STCW), 1978. Actually above-mentioned evaluation is deemed to make foundation in order to enhance the efficiency of shipboard education by surveying the satisfaction of shipboard training for nautical part cadets by the group. In this paper, we carried out the questionnaire survey to study satisfactory value and the reason of dissatisfaction of 113 cadets being trained on board the Training Ship in Maritime College of Korea Maritime University(K. M. U.). The results were calculated by frequency and percentage ; the significance of difference among Department groups like Maritime Transportation Science, Maritime Police and Ship Operating Systems Engineering was analysed by $X^2$ inspection. The major results of above analysis were as follows : First training chance for dadets was very little for being overflowed on board the training ship of the K. M. U. Second, special type of Training Ship HANBADA and HANNARA made the adaptability to merchant vessel's handling restricted. Third, cadets could not manage ratings directly, therefore the education in regard to seafaring management was limited to the theoretical instruction which leads to the low level of satisfaction. And lastly, low value of satisfaction for Drydocking Education in Shipyard was caused by cadet's leaving the Training Ship on account of the safety problems including ship and cadets.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.60 no.2
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• pp.179-185
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• 2024

The model ship of this study, the Baek-Kyung fisheries training ship of Pukyong National University, has a length between perpendiculars of 85 meters, making it not subject to the IMO maneuverability standards. However, understanding the maneuvering characteristics of the vessel is essential for safe navigation. In this regard, this study was conducted to analyze the results from the sea trials of the model ship conducted in accordance with the IMO maneuverability standards. The results of the turning tests met the standards well while in the zig-zag tests, the first overshoot angle exceeded the standard in the 10°/10° test; however, such results met with a difference of 1.8° in the 20°/20° test. Additionally, using the course-stability discrimination formula, the calculated value was -0.0051, indicating unstable course-stability. The results of the stopping tests met the standards well. It is hoped that the analyzed maneuvering characteristics of the model ship from the study results will contribute to the safety of ship navigation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.2
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• pp.226-232
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• 2024

During scuba diving in Korea, accidents involving bodies being struck by the ship propeller when entering and exiting the water, repeatedly occur every year. In response to the need to reduce accidents and implement safety management measures, Korea has established regulations for the installation and management of propeller guards. However, owing to the absence of clear production regulations in domestic laws and regulations, the installation standards are ambiguous, and the inspection items are limited to the appearance and fixation status. As a result, the safety of divers in propeller accidents is not guaranteed. Therefore, this study was conducted to specify the current legal requirements for the installation and inspection of propeller guards. To achieve this goal, we conducted a thorough analysis of the current state of domestic and foreign propeller guards and the legal factors pertaining to safety standards. Based on this analysis, we identified specific areas for improvement and proposed a plan to enhance the system for installation and inspection. The installation standards for propeller guards were clearly outlined in terms of the lattice size and material. Additionally, inspection standards were proposed for appearance, fixation, and material condition, along with clear indicators for assessing them.