• Earthquakes and Structures
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• v.24 no.4
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• pp.259-274
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• 2023

In this paper, mechanical properties of periodic foundation made of concrete and rubber are investigated by a parametric study using the finite element method (FEM). Periodic foundation is a special type of seismic isolation foundation used in civil engineering, which is inspired by the meso-scale structure of phononic crystals in solid-state physics. This type of foundation is capable of reducing the seismic wave propagating though the foundation, therefore providing additional protection for the structures. In the FEM analysis, layered periodic foundation is frequently modelled due to its simplicity in numerical modeling. However, the isolation effect of periodic foundation on nuclear power plant has not been fully discussed to the best knowledge of authors. In this work, we construct four numerical models of nuclear power plant with different foundations to investigate the seismic isolation effects of periodic foundations. The results show that the layered periodic foundation can increase the natural period of the nuclear power plant like traditional base isolation systems, which is beneficial to the structures. In addition, the seismic response of the nuclear power plant can also be effectively reduced in both vertical and horizontal directions when the frequencies of the incident waves fall into some specific frequency bandgaps of the periodic foundation. Furthermore, it is demonstrated that the layered periodic foundation can reduce the amplitude of the floor response spectrum, which plays an important role in the protection of the equipment.

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.1858-1868
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• 2021

Resisting an accidental impact of large commercial aircrafts is an important aspect of advanced nuclear power plant (NPP) design. Especially after the 9·11 event, some regulations were enacted, which required the design of NPPs should consider the accidental impact of large commercial aircrafts. Normal working of equipment is important for stopping reactor under an impact when an NPP is in operation. However, there is a lack of reliable analysis and research on the impact test of nuclear prototype equipment. Therefore, in order to study the response of the equipment under high acceleration impact, a centrifugal pump is selected as the research object to perform the impact test. A horizontal half-sinusoidal pulse wave was applied to the working pump. The test results show that the horizontal response of the motor and flange is greater compared to other parts, as well as the vertical response of the coupling. The stress response of the pump body support and motor support is high, hence these parts should be considered in the design of the pump. Finally, combined with the damage and stress evaluation results of the pump under different amplitudes, the ultimate impact acceleration that the pump can withstand is given.

• Fire Protection Technology
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• s.10
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• pp.27-33
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• 1991

The chernobyl disaster, the most serious and recent incident at an atomic plant, focussed worldwide attention on the danger of nuclear power. In this article, We discuss the fire hazards in nucleer power stations and some of the precautions necessary. Also this deals with each of the reactor components in turn, and the examples of incidents in the nuclear power stations are briefty discribed.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2519-2528
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• 2022

The child pick-up behavior of parents during an emergency can cause heavy traffic congestion and failing to evacuate an affected area successfully. In this study, we analyzed the effect of child pick-up behavior using, as an example, a nuclear power plant accident caused by an earthquake, which is a typical no-notice emergency. A quake was assumed to occur near the Shin-Kori nuclear power plant in Ulsan, Korea, resulting in a nuclear power plant accident. An agent-based dynamic simulation model using VISSIM was employed to conduct sensitivity analyses with different child pick-up rates. The results confirmed that parents are a major cause of congestion and a vulnerable class in an emergency evacuation. The child pick-up behavior caused significant traffic congestion, and parents who pick up their children showed a higher evacuation failure rate.

• Journal of the Society of Disaster Information
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• v.17 no.3
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• pp.500-511
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• 2021

Purpose: This study seeks to draw out implications that must be considered in the process of establishing measures to evacuate residents in preparation for domestic nuclear disasters by conducting an investigation about the disaster situation at the time of the Fukushima nuclear power plant explosion, emergency warning situation for residents protection, evacuation situation and In addition to investigating problems and measures raised in the resident protection system at that time. Method: A literature survey was conducted focusing on reports published by Japan's national, parliament, local governments and related agencies from right after the Great East Japan Earthquake to the present. Result: Found out what needs to be considered in the process of establishing domestic radiation disaster measures through the results of the survey on the problems and countermeasures derived from the process of evacuation of residents at the time of the Fukushima nuclear power plant explosion. Conclusion: The reviews were classified into four categories and detailed reviews were presented.

• Asian Journal for Public Opinion Research
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• v.5 no.1
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• pp.1-14
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• 2017

The Fukushima nuclear accident caused by an earthquake and a subsequent tsunami on March 11, 2011 has seriously impacted the environment surrounding the Fukushima Daiichi nuclear power plant. While all the residents near the plant were evacuated from the area deemed uninhabitable after the accident, residents of the neighboring area outside of the evacuation zone still seem to live in fear of invisible radiation. To understand Fukushima residents' thinking about the environmental risks that accompany a nuclear disaster, we utilize a poll of the residents of Fukushima conducted in 2013. Based on the survey data, we reveal factors that seem to strongly affect their knowledge and concerns about nuclear power plants. The results of the multivariate analysis show the importance of the following two factors: (1) confidence in mass media, and (2) trust in institutions in charge of administering the accident, especially the central government, the Nuclear and Industrial Safety Agency, and Tokyo Electric Power Company. We conclude that the more people trust mass media and particular institutions, the more likely it is that they are have an elevated sense of anxiety and fear of the presence of nuclear plants.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.397-416
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• 2020

Investigations of the commercial aircraft impact effect on nuclear island infrastructures have been drawing extensive attention, and this paper aims to perform the safety assessment of Generation III nuclear power plant (NPP) buildings subjected to typical commercial aircrafts crash. At present Part II, based on the verified finite element (FE) models of aircrafts Airbus A320 and A380, as well as the NPP containment and auxiliary buildings in Part I of this paper, the whole collision process is reproduced numerically by adopting the coupled missile-target interaction approach with the finite element code LS-DYNA. The impact induced damage of NPP plant under four impact locations of containment (cylinder, air intake, conical roof and PCS water tank) and two impact locations of auxiliary buildings (exterior wall and roof of spent fuel pool room) are evaluated. Furthermore, by considering the inner structures in the containment and raft foundation of NPP, the structural vibration analyses are conducted under two impact locations (middle height of cylinder, main control room in the auxiliary buildings). It indicates that, within the discussed scenarios, NPP structures can withstand the impact of both two aircrafts, while the functionality of internal equipment on higher floors will be affected to some extent under impact induced vibrations, and A380 aircraft will cause more serious structural damage and vibrations than A320 aircraft. The present work can provide helpful references to assess the safety of the structures and inner equipment of NPP plant under commercial aircraft impact.

• Asian Journal for Public Opinion Research
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• v.2 no.3
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• pp.172-195
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• 2015

Multiple nationwide opinion surveys, carried out by the government (cabinet office), major media (national newspapers and NHK), the National Institute for Environmental Studies, and the Atomic Energy Society of Japan, have revealed that the Fukushima nuclear accident has heightened people's perception of disaster risks, fear of nuclear accidents, and increased recognition of pollution issues, and has changed public opinion on nuclear energy policy. The opinion gap on nuclear energy policy between specialists and lay people has widened since the disaster. The results of the Japanese General Social Survey data show that objections to the promotion of nuclear energy are strong among females, and weaker among young males and the supporters of the LDP. These findings are similar to the data collected after the Chernobyl accident. People who live in a 70km radius of nuclear plants tend to evaluate nuclear disaster risks higher. Distance from nuclear plants and the perception of earthquake risk interactively correlate with opinions on nuclear issues. Among people whose evaluation of earthquake risk is low, those who live nearer to the plants are more likely to object to the abolishment of nuclear plants. It was also found that the nuclear disaster has changed people's behavior; they now try to save electricity. The level of commitment to energy saving is found to relate to opinions on nuclear issues.

• 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.

• Journal of Internet of Things and Convergence
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• v.6 no.1
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• pp.73-81
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• 2020

The internet of things (IoT) using cloud computing is applied to nuclear industry in which the nuclear power plant (NPP) accident is analyzed for the safety assessment. The Fukushima NPP accident is modeled for the accident simulations where the earthquake induced plant failure accident is used for analyzing the cloud computing technology. The fast and reasonable treatment in the natural disaster was needed in the case of the Fukushima. The real time safety assessment (RTSA) and the Monte-Carlo real time assessment (MCRTA) are constructed. This cloud computing could give the practicable method to prepare for the future similar accident.