• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.3102-3113
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• 2023

Following the Fukushima nuclear disaster, the simulation of accidents in the spent fuel pool has become more noticeable. Despite the low amount of decay heat power, the consequences of the accidents in a spent fuel pool (SFP) can be severe due to the high content of long-lived radionuclides and lack of protection by the pressure vessel. In this study, the loss-of-cooling accident (LOFA) for the VVER-1000/V446 spent fuel pool is simulated by employing RELAP5 and MELCOR 1.8.6 as the best estimate and severe accident analysis codes, respectively. For two cases with different total power levels, decay heat of spent fuels is calculated by ORIGEN-II code. For modeling SFP of a VVER-1000, a qualified nodalizations are considered in both codes. During LOFA in SFP, the key sequences such as heating up of the pool water, boiling and reducing the water level, uncovering the spent fuels, increasing the temperature of the spent fuels, starting oxidation process (generating Hydrogen and extra power), the onset of fuel melting, and finally releasing radionuclides are studied for both cases. The obtained results show a reasonable consistency between the RELAP5 and MELCOR codes, especially before starting the oxidation process.

• KNOM Review
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• v.22 no.3
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• pp.31-39
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• 2019

This paper introduces our research results of SDN/SON-based emergeny communications system for nuclear power plant under extreme natural diaster like Fukusima nuclear power plant incident. In such a extreme situation, nuclear power plant operational staffs which do not have technical knowledge of network provisioning and operations have to deploy the emergency network. Thus our proposed system provides capabilities to provision an emergency network autonomically and enable voice and data services. It also describes our PoC system developed based on the proposed core technology and architecture with the results of system verification testing.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.644-654
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• 2024

After the Tohoku earthquake and tsunami (Japan, 2011), regulatory efforts to mitigate external hazards have increased both the safety requirements and the total capital cost of nuclear power plants (NPPs). In these circumstances, identifying not only disaster robustness but also cost-effective capacity setting of NPPs has become one of the most important tasks for the nuclear power industry. A few studies have been performed to relocate the seismic capacity of NPPs, yet the effects of multiple hazards have not been accounted for in NPP capacity optimization. The major challenges in extending this problem to the multihazard dimension are (1) the high computational costs for both multihazard risk quantification and system-level optimization and (2) the lack of capital cost databases of NPPs. To resolve these issues, this paper proposes an effective method that identifies the optimal multihazard capacity of NPPs using a multi-objective genetic algorithm and the two-stage direct quantification of fault trees using Monte Carlo simulation method, called the two-stage DQFM. Also, a capacity-based indirect capital cost measure is proposed. Such a proposed method enables NPP to achieve safety and cost-effectiveness against multi-hazard simultaneously within the computationally efficient platform. The proposed multihazard capacity optimization framework is demonstrated and tested with an earthquake-tsunami example.

• Journal of the Society of Disaster Information
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• v.9 no.1
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• pp.78-86
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• 2013

Caused by the Cheonanham attack and the Yeonpyeongdo bombardment occurred a few years ago, and the recent North Korea's nuclear test, the war crisis between South and North Korea has been increasing. Accordingly, an interest in obtaining a temporary residential space, for the case of the outbreak of war, where people can reside safely over a period of time has been escalating. However, in the disaster relief planning guidelines of the National Emergency Management Agency, the standards on the temporary residential spaces in preparation for storm and flood or earthquake are included, but the standards on the ones in responding to war are not yet equipped. In particular, the standards on the underground temporary residential spaces that can accommodate massive victims should be developed in preparation. In this study, through a requirements analysis based on the survey of war victims and a comparative analysis between disaster-related laws and regulations, the direction of relevant system improvement for the utilization of temporary residential spaces in responding to war is established.

• Fire Science and Engineering
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• v.32 no.3
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• pp.116-122
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• 2018

In Chemical, Biological, Radiological and Nuclear (CBRN) disaster, integrated and optimized equipment package including stretcher, isolation unit, patient monitoring and treatment equipment is essential to achieve proper treatment and prevent secondary contamination. The purpose of this study was to evaluate the efficiency and ease of use of integrated CBRN disaster equipment package for disaster medical response. This study was a randomized crossover study using a manikin simulation for emergency medical technitian (EMT). All participants used the existing devices and prototype of integrated CBRN disaster equipment package alternately. Efficiency was measured by time from vital sign change to detection or treatment application. Ease was use was measured by questionnaires for each patient monitor, stretcher care and isolation unit. 12 EMTs were enrolled. hypoxia-detection time of integrated equipment group was significantly shorter than existing equipment group (4.9 s (3.8-3.9) vs 3.5 s (2.5-3.9), p < 0.05). There was decreasing tendency of ECG change detection and facial mask oxygen supply but no statistical significance was observed. Overall satisfaction of patient monitoring device in integrated equipment group was significantly higher than existing devices (4(3.5-5) vs 3(3-3), p < 0.05). The use of integrated CBRN disaster equipment package shortened the hypoxia detection time and improved usability of vital sign monitor compared to existing devices.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.647-653
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• 2017

The purpose of this study is to provide basic data for policy making by understanding preparation plans and awareness of nuclear accidents and radiation terrorism among police officers in the vicinity of nuclear power plants. 221 police officers working in Busan metropolitan city were surveyed and their perception of disaster response was analyzed by organizational structure, command ability, and opinion management. As a result, there was no significant difference in disaster response perception by gender and command class (p>.05). There was statistically significant difference in the ability of command in age and ability according to work experience. As a result of the correlation analysis, there were statistically significant correlations among the three items of organizational structure perception, command ability, and opinion management (+0.5) (p<.01). Overall, it was positive for the police system, and it was well aware of the police work in case of radiation accidents and terrorist attacks. The purpose of this study is to provide basic data for policy making by understanding the coping and awareness of nuclear accidents and radiation terrorism among police officers in the vicinity of nuclear power plants.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.463-470
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• 2016

This experimental research as media effect study explores the effect of the current documentary that deals with radioactive contamination widely spread by fukushima nuclear accident on political and social recognition of domestic audience. Proceeding studies about media effect dealt mainly with news contents of TV, newspaper and internet. However studies on the effect of current documentary as non news contents on audience that provide us with profound information by various subjects are very few. Especially it is difficult to find studies about disaster documentary dealing with radioactive contamination having much effect on global environment. Accordingly this research implemented experimental study to find out the effect of current documentary that deals with radioactive contamination by fukushima nuclear accident on political and social recognition of audience. This research found that subjects exposed to the current documentary considered outdated nuclear power plant more seriously, supporting the opposition party more positively, claiming shutdown of outdated nuclear power plant, and opposing additive construction of nuclear power plant than subjects not exposed to the current documentary.

• Journal of the Society of Disaster Information
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• v.18 no.2
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• pp.252-260
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• 2022

Purpose: As the intensity and frequency of natural hazards are increasing due to climate change, external events that affecting nuclear power plants(NPPs) may increase. NPPs must be protected from external events such as natural hazards and human-induced hazards. External events that may occur in NPPs should be identified, and external events that may affect NPPs should be identified. This study introduces the methodology of identification and screening methods for external events by literature review. Method: The literature survey was conducted on the identification and screening methods of external events for probabilistic safety assessment of NPPs. In addition, the regulations on the identification and screening of external events were investigated. Result: In order to minimize the cost of external event impact analysis of nuclear power plants, research on identifying and screening external events is being conducted. In general, in the identification process, all events that can occur at the NPPs are identified. In the screening process, external events are selected based on qualitative and quantitative criteria in most studies. Conclusions: The process of identifying and screening external events affecting NPPs is becoming important. This paper, summarize on how to identify and screen external events for a probabilistic safety assessment of NPPs. It is judged that research on bounding analysis and conservative analysis methods performed in the quantitative screening process of external events is necessary.

• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.222-235
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• 2019

Since Fukushima nuclear disaster occurred in 2011, the nuclear energy policy of the international society has been in recession. However, In Korea, the nuclear-friendly policy had remained and even expanded over the last 60 years until the Park Geun-hye government. In other words, there was the path dependence of nuclear energy policy. Since the Moon Jae-in government that pledged to perform nuclear phase-out policy in 2017 was inaugurated, the nuclear-friendly policy began to swerve from the course of path dependence. Based on the mai logic of historical institutionalism, this study looked into the change of Korean nuclear policy by before and after the Fukushima nuclear accident. As the result of this research, the external situation of Fukushima Nuclear Accident became a critical turning point and led to a change in the government's policy on nuclear power. From an institutional perspective, it influenced the paradigm of nuclear power policy, policy decision structure, and laws of nuclear power. From a doer's perspective, it influenced political idea and social acceptability. Since Moon Jae-in government was inaugurated in 2017, nuclear phase-out policy has secured its institutional foundation and nuclear power policy has basically changed from nuclear-friendly policy to nuclear phase-out policy. Therefore, the energy policy of Moon Jae-in government gets out of the nuclear power based path dependency that previous governments pursued, keeps punctuated equilibrium, and changes to renewable energy oriented policy.

• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1237-1251
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• 2016

Although the horizontal component of an earthquake response can be significantly reduced through the use of conventional seismic isolators, the vertical component of excitation is still transmitted directly into the structure. Records from instrumented structures, and some recent tests and analyses have actually seen increases in vertical responses in base isolated structures under the combined effects of horizontal and vertical ground motions. This issue becomes a great concern to facilities such as a Nuclear Power Plants (NPP), with specialized equipment and machinery that is not only expensive, but critical to safe operation. As such, there is considerable interest worldwide in vertical and three-dimensional (3D) isolation systems. This paper examines several vertical and 3D isolation systems that have been proposed and their potential application to modern nuclear facilities. In particular, a series of case study analyses of a modern NPP model are performed to examine the benefits and challenges associated with 3D isolation compared with horizontal isolation. It was found that compared with the general horizontal isolators, isolators that have vertical frequencies of no more than 3 Hz can effectively reduce the vertical in-structure responses for the studied NPP model. Among the studied cases, the case that has a vertical isolation frequency of 3 Hz is the one that can keep the horizontal period of the isolators as the first period while having the most flexible vertical isolator properties. When the vertical frequency of isolators reduces to 1 Hz, the rocking effect is obvious and rocking restraining devices are necessary.