• Title/Summary/Keyword: Naval Strategy

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Numerical study on CMT boron replenishment strategy for an AP1000 nuclear power unit

  • Wang, Hong;Zhang, Miao;Li, Jialong;Wang, Junpeng
    • Nuclear Engineering and Technology
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    • v.54 no.6
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    • pp.2321-2328
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    • 2022
  • The passive safety system is adopted in an AP1000 nuclear power unit to improve the operation safety of the whole unit. However, due to boron diffusion and periodic sampling, boron dilution occurs in the core makeup tank. The boron replenishment process in the core makeup tank is essential and becomes particularly important. Based on the validated models, this article numerically investigates the influence of the replenishment flow rate and the position on the boron distribution in the core makeup tank. The thermal fatigue phenomenon of the "T" connection caused by replenishment is analyzed. Finally, the replenishment strategy is proposed to benefit both boron mixing in the core makeup tank and eliminating the thermal fatigue of the "T" connection.

The Stances of Neighboring States to the Indo-Pacific Strategy and Its Implications for the South Korean Navy (인도·태평양 전략에 대한 주변국 입장, 한국 해군에 대한 함의)

  • Han, Jong-Hwan
    • Strategy21
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    • s.46
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    • pp.5-28
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    • 2020
  • In 2019, the U.S. Department of Defense and the U.S. Department of State issued two reports to announce their plan to fulfill "free and open Indo-Pacific". Two reports commonly insisted on the support and participation from allies and partners to maintain security and stability in the Indo-Pacific. In response to this, neighboring states in the Indo-Pacific, including Japan, Australia, India, ASEAN, and Taiwan have different perspectives and stances based on their national interests. South Korea, too, has not clearly announced its position because they need to consider the alliance between the U.S. and South Korea as well as relationships between South Korea and China. This report focuses on the stances of neighboring states to the Indo-Pacific strategy and expected pros and cons of the participation of the strategy. In addition, when considering the name of strategy, the Indo-Pacific, naval power will be a main instrument to implement the strategy. Thus, this study also investigates the role of naval power in the Indo-Pacific strategy.

Naval Arms Race in Northeast Asia (동북아 해군력 군비경쟁)

  • Kim, Duk-ki
    • Strategy21
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    • s.43
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    • pp.125-174
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    • 2018
  • The purpose of this paper is to analyze the status of naval arms race in Northeast Asia. To this end, the scope of the research was limited to national security strategies, maritime strategies and naval strengthening of the United States, China, Russia and Japan. The major powers' active maritime strategies and naval arms race give some strategic implications to the Republic of Korea Navy as follows. First, China and Japan, unlike the past, are actively using submarines in offshore waters including the Korean Peninsula. Therefore, the ROK Navy must successfully promote the Jangbogo-III-class submarine, which is currently constructed, and get a nuclear-powered submarine and P-8 MPA capable of long-range and long-time operations to enhance ASW capability. Second, North Korea's current building submarines capable of loading SLBMs and SLBMs are a new threat to the ROK Navy. The current building KAMD, which focuses on terminal phase defense, cannot effectively respond to North Korea's SLBMs and should be converted to a multi-layered defense system including SM-3 at a mid-course phase. Third, as China militarizes the South China Sea, the instability of the South China Sea is growing. Therefore, the ROK Navy should strengthen its maritime cooperation with the regional countries such as Japan and ASEAN navies to protect SLOC. In conclusion, the ROK Navy needs to build a strong naval power to keep in mind that the 21st century naval rivalry in Northeast Asia is accelerating. The navy must do one's best to protect national strategic and vital interests by strengthening cooperation with regional countries. South Korea is also accelerating its defense reforms in accordance with the pattern of future warfare and the ROK Navy do one's best to have a balanced naval capability capable of actively operating in the offshore waters.

Strategic and Tactical Use of Naval Ship for Maritime Defense during the reign of King Sejong (조선 세종시대 병선(兵船)의 해방(海防)전략·전술)

  • Min, Jang-won
    • Strategy21
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    • s.44
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    • pp.177-212
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    • 2018
  • The purpose of this article is to examine the 'Discussion of maritime defense' which began to be discussed from the late Goryeo dynasty to the early Joseon dynasty and the process of establishing a maritime defense system. Also it can identify changes in the aspects of the naval ship operation and their strategic tactics during the reign of King Sejong. Japanese raiders began a full-scale invasion from 1350 at the late Goryeo Dynasty, So the government realized the need to raise the 'Sea power' and to organize the maritime defense system for defending enemy invasion. for example, the reinforcement of naval forces, construction of warships, develoment of weapon systems and so on. which have achieved remarkable growth while continuing, have also been used to carry out a three-time 'Conquest of Daemado' in 1389, 1396, 1419. Until then, however, it is difficult to interpret that the naval forces had a systematic and organizational combat operation system. According to fighting patterns on combat reports before the early days of King Sejong's reign, Our naval forces had no advantage over the Japanese raiders in terms of their capabilities and tactics. Then, the period of King Sejong marked a watershed in maritime defense history. Based on accumulated experience of naval battles and force Projections, The paradigm shift of the naval strategic tactics for maritime defense has occurred. First, the capability of the naval vessels has improved. for example, ship speed, durability, and weather resistance. Through these efforts, navy forces were able to pursue and attack, destroy enemy's ships by taking advantage of the 'Ship speed superiority'. This has led to tactical shifts from defensive to offensive. Second, purpose to support offensive tactics, the government put a strategic plan into practice that is the forward depolyment of naval bases from the inland to the coast, considering the 'sea environment' and 'threat'. By doing so, Joseon dynasty was able to secure 'the command of the sea'. This may be a little different from the perception of the so-called 'peace period' that King Sejong's era. We need to remember that Joseon dynasty was working hard for its defense. When studying history of maritime defense, these strategic and tactical elements must be fully considered. Only then we can have a coherent understanding of the many naval battles in the past, including the Imjin War(1592-1598).

PRC Maritime Operational Capability and the Task for the ROK Military (중국군의 해양작전능력과 한국군의 과제)

  • Kim, Min-Seok
    • Strategy21
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    • s.33
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    • pp.65-112
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    • 2014
  • Recent trends show that the PRC has stepped aside its "army-centered approach" and placed greater emphasis on its Navy and Air Force for a wider range of operations, thereby reducing its ground force and harnessing its economic power and military technology into naval development. A quantitative growth of the PLA Navy itself is no surprise as this is not a recent phenomenon. Now is the time to pay closer attention to the level of PRC naval force's performance and the extent of its warfighting capacity in the maritime domain. It is also worth asking what China can do with its widening naval power foundation. In short, it is time to delve into several possible scenarios I which the PRC poses a real threat. With this in mind, in Section Two the paper seeks to observe the construction progress of PRC's naval power and its future prospects up to the year 2020, and categorize time frame according to its major force improvement trends. By analyzing qualitative improvements made over time, such as the scale of investment and the number of ships compared to increase in displacement (tonnage), this paper attempts to identify salient features in the construction of naval power. Chapter Three sets out performance evaluation on each type of PRC naval ships as well as capabilities of the Navy, Air Force, the Second Artillery (i.e., strategic missile forces) and satellites that could support maritime warfare. Finall, the concluding chapter estimates the PRC's maritime warfighting capability as anticipated in respective conflict scenarios, and considers its impact on the Korean Peninsula and proposes the directions ROK should steer in response. First of all, since the 1980s the PRC navy has undergone transitions as the focus of its military strategic outlook shifted from ground warfare to maritime warfare, and within 30 years of its effort to construct naval power while greatly reducing the size of its ground forces, the PRC has succeeded in building its naval power next to the U.S.'s in the world in terms of number, with acquisition of an aircraft carrier, Chinese-version of the Aegis, submarines and so on. The PRC also enjoys great potentials to qualitatively develop its forces such as indigenous aircraft carriers, next-generation strategic submarines, next-generation destroyers and so forth, which is possible because the PRC has accumulated its independent production capabilities in the process of its 30-year-long efforts. Secondly, one could argue that ROK still has its chances of coping with the PRC in naval power since, despite its continuous efforts, many estimate that the PRC naval force is roughly ten or more years behind that of superpowers such as the U.S., on areas including radar detection capability, EW capability, C4I and data-link systems, doctrines on force employment as well as tactics, and such gap cannot be easily overcome. The most probable scenarios involving the PRC in sea areas surrounding the Korean Peninsula are: first, upon the outbreak of war in the peninsula, the PRC may pursue military intervention through sea, thereby undermining efforts of the ROK-U.S. combined operations; second, ROK-PRC or PRC-Japan conflicts over maritime jurisdiction or ownership over the Senkaku/Diaoyu islands could inflict damage to ROK territorial sovereignty or economic gains. The PRC would likely attempt to resolve the conflict employing blitzkrieg tactics before U.S. forces arrive on the scene, while at the same time delaying and denying access of the incoming U.S. forces. If this proves unattainable, the PRC could take a course of action adopting "long-term attrition warfare," thus weakening its enemy's sustainability. All in all, thiss paper makes three proposals on how the ROK should respond. First, modern warfare as well as the emergent future warfare demonstrates that the center stage of battle is no longer the domestic territory, but rather further away into the sea and space. In this respect, the ROKN should take advantage of the distinct feature of battle space on the peninsula, which is surrounded by the seas, and obtain capabilities to intercept more than 50 percent of the enemy's ballistic missiles, including those of North Korea. In tandem with this capacity, employment of a large scale of UAV/F Carrier for Kill Chain operations should enhance effectiveness. This is because conditions are more favorable to defend from sea, on matters concerning accuracy rates against enemy targets, minimized threat of friendly damage, and cost effectiveness. Second, to maintain readiness for a North Korean crisis where timely deployment of US forces is not possible, the ROKN ought to obtain capabilities to hold the enemy attack at bay while deterring PRC naval intervention. It is also argued that ROKN should strengthen its power so as to protect national interests in the seas surrounding the peninsula without support from the USN, should ROK-PRC or ROK-Japan conflict arise concerning maritime jurisprudence. Third, the ROK should fortify infrastructures for independent construction of naval power and expand its R&D efforts, and for this purpose, the ROK should make the most of the advantages stemming from the ROK-U.S. alliance inducing active support from the United States. The rationale behind this argument is that while it is strategically effective to rely on alliance or jump on the bandwagon, the ultimate goal is always to acquire an independent response capability as much as possible.

Introduction of development case of Korea navy welfare portal system and proposal of development strategy that consider security issues (해군복지포탈체계 개발 사례 소개 및 보안성을 고려한 발전방안 제안)

  • Kim, Ildo;Kim, Junsang
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.10a
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    • pp.1097-1100
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    • 2009
  • Korean navy is developing an information system-based a computer - network for efficient business process and information exchange and management efficiency expansions. Naval welfare portal was developed to the part, and newly development at present to solve a problem. But inconvenient point in the army, most people do not has personal Internet PC. At this paper, we explain case study of naval welfare portal, and propose development strategy that consider of security issue.

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East Asian Maritime Security: Naval Power vs. Normative Power (동아시아 해양안보 : 해군력인가 해양법인가?)

  • Koo, Min-Gyo
    • Strategy21
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    • s.40
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    • pp.115-130
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    • 2016
  • The security environment surrounding the East Asian seas is rapidly changing due to the naval arms race among coastal states. The arms race is likely to worsen the security dilemma of the countries involved, thus increasing the chances for armed conflicts. It is too early to tell how the contemporary naval arms race in the region will evolve. But, for sure, the level of uncertainty is increasingly becoming high and intense. At the same time, there is emerging a legal warfare or lawfare among the rival countries. In particular, the United States and China have been involved in a serious debate about the nature and scope of the right of innocent passage and freedom of navigation in other countries' maritime zones. In collaboration with its regional allies, the United States has also put normative pressures on China with its excessive claims in the South China Sea. The latest arbitral tribunal case between the Philippines and China illustrates the point. With both arms race and normative competition in play, the future of East Asian maritime security will remain very complex and uncertain.

The effects of geometrical buoy shape with nonlinear Froude-Krylov force on a heaving buoy point absorber

  • Kim, Sung-Jae;Koo, Weoncheol;Kim, Moo-Hyun
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.13 no.1
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    • pp.86-101
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    • 2021
  • This study examined the effects of buoy shape and Nonlinear Froude-Krylov force (NFK) on a heaving-buoy-type Wave Energy Converter (WEC). Based on the Maclaurin expansion, the theoretical solutions of the NFK were derived for three different buoy shapes; hemispheric buoy, circular vertical cylinder, and truncated conical cylinder. A hydraulic power take-off system was adopted, and the latching control strategy was applied to maximize the extracted power from the WEC. The nonlinear effects of the Froude-Krylov force and restoring force on the heaving point absorber were investigated by comparing the heave Response Amplitude Operator (RAO) and time-averaged power extraction. The results showed that the conventional linear analyses were overestimated by up to 50% under the high amplitude wave condition. The latching control strategy was the most effective when peak wave period of regular or irregular wave was 0.4-0.45 times the heave natural period of the buoy.

Block Erection Simulation Using the Integrated System of Combined Discrete Event and Discrete Time Simulation Kernel (이산 사건 및 이산 시간 혼합형 시뮬레이션 커널의 통합 시스템을 이용한 블록 탑재 시뮬레이션)

  • Cha, Ju-Hwan;Roh, Myung-Il;Cho, Doo-Yeoun;Lee, Kyu-Yeul
    • Journal of the Society of Naval Architects of Korea
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    • v.46 no.3
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    • pp.303-312
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    • 2009
  • Recently, requests for the accurate process planning using modeling and simulation technique are increasing in many engineering fields including shipbuilding industry. In this study, Combined DEVS(Discrete EVent System specification) and DTSS(Discrete Time System Specification) simulation kernel is developed, and an integration strategy of dynamics simulation module and graphics module is also implemented. To evaluate the efficiency and applicability of the simulation kernel and integration strategy, these are applied to the block erection simulation of offshore structures.

A Study for Improving Quality Management System of Naval Ships to Enhance Safety (함정 안전성 향상을 위한 품질관리체계 개선 방안 연구)

  • Ki-chul, Hwang;Jong-ha, Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.59 no.6
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    • pp.432-438
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    • 2022
  • This study focuses on improving quality management system of naval ships to enhance safety. Recently, there were problems caused by the lack of quality management system when building Korea naval ships. Foreign naval ships are designed and built through certification by professional organizations in the commercial sector to reduce budget and enhance ship safety. Merchant ships are designed, built, operated and maintained by the organizations in accordance with the Ship Safety Act. When naval ships are exported, the ordering country requires the certification from the international classification to ensure the safety and reliability of ships. Through this study, as a method of improving the quality management system of naval ships, design verification, equipment certification and construction survey using expertise of the organizations are proposed when designing and building the naval ships.