• Nuclear Engineering and Technology
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• v.50 no.7
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• pp.997-1005
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• 2018

The regulatory periodic safety inspection system is one of the most important methods for confirming the safety of nuclear power plants and the defense in depth in nuclear safety is the most important basic means for accident prevention and mitigation. Recently, a new regulatory technology based on risk-informed and safety performance has been developed and used in advanced countries. However, since the domestic periodic inspection system is being used in the same way over 30 years, it is necessary to know how the inspection contributes to the safety confirmation of the nuclear power plants. In this study, the domestic periodic inspection system currently in use was analyzed from the perspective of defense in depth in nuclear safety. In addition, the analysis results were compared to the U.S. NRC's safety inspection system to obtain consistency and lessons in this study. As a result of analysis, the NRC's safety inspections were distributed almost evenly at the all levels of defense in depth, while in the case of domestic inspection, they were heavily focused on the level 1 of defense in depth. Therefore, it appeared urgent to improve the inspection system to strengthen the other levels of defense in depth in nuclear safety.

• Korean Journal of Legislative Studies
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• v.25 no.3
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• pp.69-96
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• 2019

This paper is written to suggest several recommendations for South Korea to deter and defend North Korean nuclear threat, when North Korea does not seem to give up its nuclear weapons and the US's extended deterrence including the nuclear umbrella could remain uncertain. For this purpose, it explains key options regarding nuclear deterrence and defense by non-nuclear weapon state. It evaluates the current status of South Korean non-nuclear preparedness against North Korean nuclear threat and provides some recommendations to improve the preparedness. As a result, this paper concluded that South Korean non-nuclear preparedness against North Korean nuclear threat was not that reliable. The preparedness has weakened since the South Korean effort to denuclearize North Korea through negotiations in 2018. In this sense, South Korea could have serious problems in protecting its people from North Korean nuclear threat if the US promise of extended deterrence is not implemented. South Korea should focus on its decapitation operation to North Korean highest leaders in case of North Korean nuclear attack based on a minimal deterrence concept. It should be prepared to conduct preventive strikes instead of preemptive strikes due to North Korea's development of solid fuel ballistic missiles. It should integrate its Ballistic Missile Defense with that of the US forces in Korea. South Korea should make a sincere effort for nuclear civil defense including construction of nuclear shelters.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.209-217
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• 2020

North Korea has steadily implemented defense reforms to strengthen its national defense capabilities, and in particular, has made military technology development and military industrial capability strengthening as the focus of national defense reform. North Korea's defense reform ultimately aimed at securing nuclear posture, and as technical achievements accumulated in the Kim Jung-Un era, it led to the development of military strength such as hydrogen bombs and ICBM/SLBM. Having secured nuclear capability, North Korea is also pursuing a symmetricality in the conventional military strength by securing a strategic advantage by pursuing the modernization of the conventional weapon systems through defense reform again. Up to now, North Korea's defense reform has succeeded in establishing a new ruling system for Kim Jung-Un and creating a driving force for negotiations with the United States.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.10a
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• pp.135-136
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• 2017

• Nuclear Engineering and Technology
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• v.46 no.6
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• pp.803-816
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• 2014

Defense-in-depth is a fundamental safety principle for the design and operation of nuclear power plants. Despite its general appeal, defense-in-depth is not without its drawbacks, which include its potential for concealing the occurrence of hazardous states in a system, and more generally rendering the latter more opaque for its operators and managers, thus resulting in safety blind spots. This in turn translates into a shrinking of the time window available for operators to identify an unfolding hazardous condition or situation and intervene to abate it. To prevent this drawback from materializing, we propose in this work a novel safety principle termed "observability-in-depth". We characterize it as the set of provisions technical, operational, and organizational designed to enable the monitoring and identification of emerging hazardous conditions and accident pathogens in real-time and over different time-scales. Observability-in-depth also requires the monitoring of conditions of all safety barriers that implement defense-in-depth; and in so doing it supports sensemaking of identified hazardous conditions, and the understanding of potential accident sequences that might follow (how they can propagate). Observability-in-depth is thus an information-centric principle, and its importance in accident prevention is in the value of the information it provides and actions or safety interventions it spurs. We examine several "event reports" from the U.S. Nuclear Regulatory Commission database, which illustrate specific instances of violation of the observability-in-depth safety principle and the consequences that followed (e.g., unmonitored releases and loss of containments). We also revisit the Three Mile Island accident in light of the proposed principle, and identify causes and consequences of the lack of observability-in-depth related to this accident sequence. We illustrate both the benefits of adopting the observability-in-depth safety principle and the adverse consequences when this principle is violated or not implemented. This work constitutes a first step in the development of the observability-in-depth safety principle, and we hope this effort invites other researchers and safety professionals to further explore and develop this principle and its implementation.

• Convergence Security Journal
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• v.16 no.3_2
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• pp.13-23
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• 2016

North Korea had recently conducted the fourth nuclear test and ICBM tests, dared nuclear provocation targeting the Korea and the international community. It is determined based on experiments of nuclear and missile in progress in North Korea that the technical level of nuclear force reached the completion stage of standardization, lightweight, and variation. It is expected to become reality that North Korea executes the nuclear provocation targeting the Korea and the international community in the near future. Nuclear bomb is an absolute weapon that the logic of counterattack after allowing the first strike of the other party cannot be applied due to its tremendous destructive power. Therefore, as the opponent to North Korea that it decided to hold the nuclear, the exercise of anticipatory self-defense in order to guarantee a minimum of right to life is not a choice, but the only essential correspondence concept. At the moment that the North Korean nuclear provocation is expected in the near future, it shall be provided with competence to strike the origin region of provocation by forming a national consensus of preemptive strike enforcement. Also, in preparation for the fifth nuclear test of North Korea, which is anticipated, the national competence must be mobilize to be able to ensure the 'Nuclear Option' from the international community.

• Nuclear Engineering and Technology
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• v.52 no.3
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• pp.626-632
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• 2020

Radiation Portal Monitors (RPMs) are our primary border defense against nuclear smuggling, but are they still the best way to spend limited funds? The purpose of this research is to strategically compare RPM defense at the border with state-side mobile detectors. Limiting the problem to a comparison of two technologies, a decision-maker can prioritize how to best allocate resources, by reinforcing the border with stationary overt RPMs, or by investing in Mobile Radiation Detection Systems (MRDs) which are harder for an adversary to detect but may have other weaknesses. An abstract, symmetric network was studied to understand the impact of initial conditions on a network. An asymmetric network, loosely modeled on a state transportation system, is then examined for the technology that will maximally suppress the adversary's success rate. We conclude that MRDs, which have the advantage of discrete operation, outperform RPMs deployed to a border. We also conclude that MRDs maintain this strategic advantage if they operate with one-tenth the relative efficiency of their stationary counter-parts or better.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.2
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• pp.235-245
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• 2018

This study first analyzes the necessity and the validity of procuring nuclear-powered submarines, and presents an optimization model as an integer program to determine a minimum required level of them. For an optimization model, we characterize a submarine's mission, ability and availability, and apply these to the model by constraints. Then, we assign the submarines available currently and the nuclear-powered submarines, that will be newly introduced, to the predefined missions over the planning time periods in a way that the number of nuclear-powered submarines be minimized. Randomly generated missions are employed to solve a mission assignment problem, and the results show that our integer programming model provides an optimal solution as designed, and this can provide a guideline for other weapon system procurement processes.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.135-138
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• 2012

Purpose : This research the isotope of handling was to an actual act of the radiological defense which it follows in career of the clinical pathological companies in order to inquire the interrelation for a radiological defense. Materials and Methods : The tool of this research with question from 2010 October until November did electrification Chwung Cheng and the Seoul isotope thread clinical pathological company with the object person and it investigated in direct question or mail method, the data which is collected used SPSS19.0 programs and frequency and percentage and t-test, ANOVA, it used it analyzed a multiple regression analysis method. Results : The interrelationship of the radiological defense which it follows in career was visible the interrelation which considers statistically (p<0.01). But the correlation coefficient appeared lowly with 0.196. With the variable who affects in radiological defense act it appeared with worker providing by law educations and RI license acquisitions. Conclusion : There is to business progress and the radiological defense act respects a worker safety stands the unit only is the fact which is important. Consequently a possibility of saying that the radiation worker education is necessary, it executes the education which is continuous, RI license acquisitions, there is.

• 대한핵의학회:학술대회논문집
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• 1981.05a
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• pp.109-109
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• 1981