• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.417-428
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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 III, the local damage of the rigid components of aircraft, e.g., engine and landing gear, impacting the steel concrete (SC) structures of NPP containment is mainly discussed. Two typical SC target panels with the thicknesses of 40 mm and 100 mm, as well as the steel cylindrical projectile with a mass of 2.15 kg and a diameter of 80 mm are fabricated. By using a large-caliber air gas gun, both the projectile penetration and perforation test are conducted, in which the striking velocities were ranged from 96 m/s to 157 m/s. The bulging velocity and the maximal deflection of rear steel plate, as well as penetration depth of projectile are derived, and the local deformation and failure modes of SC panels are assessed experimentally. Then, the commercial finite element program LS-DYNA is utilized to perform the numerical simulations, by comparisons with the experimental and simulated projectile impact process and SC panel damage, the numerical algorithm, constitutive models and the corresponding parameters are verified. The present work can provide helpful references for the evaluation of the local impact resistance of NPP buildings against the aircraft engine.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.381-396
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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 I, finite element (FE) models establishment and validations for both the aircrafts and NPP buildings are performed. (i) Airbus A320 and A380 aircrafts are selected as the representative medium and large commercial aircrafts, and the corresponding fine FE models including the skin, beam, fuel and etc. are established. By comparing the numerically derived impact force time-histories with the existing published literatures, the rationality of aircrafts models is verified. (ii) Fine FE model of the Chinese Zhejiang Sanao NPP buildings is established, including the detailed structures and reinforcing arrangement of both the containment and auxiliary buildings. (iii) By numerically reproducing the existing 1/7.5 scaled aircraft model impact tests on steel plate reinforced concrete (SC) panels and assessing the impact process and velocity time-history of aircraft model, as well as the damage and the maximum deflection of SC panels, the applicability of the existing three concrete constitutive models (i.e., K&C, Winfrith and CSC) are evaluated and the superiority of Winfrith model for SC panels under deformable missile impact is verified. The present work can provide beneficial reference for the integral aircraft crash analyses and structural damage assessment in the following two parts of this paper.

• 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.

• Journal of the Society of Disaster Information
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• v.10 no.2
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• pp.294-303
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• 2014

The state has the constitutional duty to secure the safety of its citizens and provide protection against any physical dangers. The Republic of Korea has a high threat of nuclear, biological and or chemical(hereafter referred to as NBC) attack from the Democratic People's Republic of Korea. Thus, the state has a responsibility to form a legislation to provide the protection for its citizens and implement duty to guarantee the human rights. Under the current legislation, the 'United Defense Act', 'Framework Act on Civil Defense' that are applied under wartime conditions are insufficient in providing the protection of the citizens of the state in the occurrence of NBC attack. Therefore, it is necessary that the 'Act for the Protection of Citizens in the occurrence of NBC Attack' is legislated to provide a system that protects the nation's citizens under the wartime conditions mentioned above. This paper incorporates a theoretical analysis of the need for the constitutional responsibility of the state to provide protection for its citizens under wartime conditions, the necessity of a specific measure to protect citizens during NBC attack, the relationship between 'Act for the Protection of Citizens in the occurrence of Nuclear, Chemical and or Biological Attack' and current legislations that are applied under wartime conditions, and the particulars of the proposed act.

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.3085-3099
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• 2021

Investigations of large commercial aircraft impact effect on nuclear power plant (NPP) buildings have been drawing extensive attentions, particularly after the 9/11 event, and this paper aims to numerically assess the damage and vibrations of NPP buildings subjected to aircrafts crash. In Part I of present paper, two shots of reduce-scaled model test of aircraft impact on NPP were conducted based on the large rocket sled loading test platform. In the present part, the numerical simulations of both scaled and prototype aircraft impact on NPP buildings are further performed by adopting the commercial program LS-DYNA. Firstly, the refined finite element (FE) models of both scaled aircraft and NPP models in Part I are established, and the model impact test is numerically simulated. The validities of the adopted numerical algorithm, constitutive model and the corresponding parameters are verified based on the experimental NPP model damages and accelerations. Then, the refined simulations of prototype A380 aircraft impact on a hypothetical NPP building are further carried out. It indicates that the NPP building can totally withstand the impact of A380 at a velocity of 150 m/s, while the accompanied intensive vibrations may still lead to different levels of damage on the nuclear related equipment. Referring to the guideline NEI07-13, a maximum acceleration contour is plotted and the shock damage propagation distances under aircraft impact are assessed, which indicates that the nuclear equipment located within 11.5 m from the impact point may endure malfunction. Finally, by respectively considering the rigid and deformable impacts mainly induced by aircraft engine and fuselage, an improved Riera function is proposed to predict the impact force of aircraft A380.

• Nuclear Engineering and Technology
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• v.51 no.6
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• pp.1540-1553
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• 2019

A nuclear power plant (NPP) is a highly complex system-of-systems as manifested through its internal systems interdependence. The negative impact of such interdependence was demonstrated through the 2011 Fukushima Daiichi nuclear disaster. As such, there is a critical need for new strategies to overcome the limitations of current risk assessment techniques (e.g. the use of static event and fault tree schemes), particularly through simulation of the nonlinear dynamic feedback mechanisms between the different NPP systems/components. As the first and key step towards developing an integrated NPP dynamic probabilistic risk assessment platform that can account for such feedback mechanisms, the current study adopts a system dynamics simulation approach to model the thermal dynamic processes in: the reactor core; the secondary coolant system; and the pressurized water reactor. The reactor core and secondary coolant system parameters used to develop system dynamics models are based on those of the Palo Verde Nuclear Generating Station. These three system dynamics models are subsequently validated, using results from published work, under different system perturbations including the change in reactivity, the steam valve coefficient, the primary coolant flow, and others. Moving forward, the developed system dynamics models can be integrated with other interacting processes within a NPP to form the basis of a dynamic system-level (systemic) risk assessment tool.

• Journal of the Korean Society of Systems Engineering
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• v.10 no.1
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• pp.17-32
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• 2014

The trade-off studies in the concept development stage to assess the relative goodness of alternative systems concepts for AE (architect engineering) design for the Barge Mounted SMR (BMSMR) is introduced. With respect to design margin, system performance, schedule and risk, the design selection is cond ucted using the following characteristics; barge mobility, system safety under the natural disaster (seismic), power output, interfacing with the other system, and the additional supporting functions as desalination. There are three findings that should be remedied; deficiencies in the assumed characteristics of the system being modeled, deficiencies in the test model, and excessively stringent system requirements. This study is performed using systems engineering approach with trade off matrix method. In order to execute this work, concept development stage is divided into three (3) phases as NA (needs analysis), CE (concept exploration), and CD (concept definition).

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.185-187
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• 2005

The reactor protection system is the most important function for the safe operation of nuclear powerplants (NPPs) in that such system protects a nuclear reactor tore whose damage can cause an enormous disaster to the nuclear facility and the public. A digital reactor protection system (DRPS) is being developed in KAERI for use in the newly-constructed NPPs and also for replacing the existing analog-type reactor Protection systems. In this paper, an software verification and validation (V&V) activities for DRPS, which are independent of the DRPS development processes, are described according to the software development life cycle. The main activities of DRPS V&V processes are the software planning documentations, the verification of software requirements specification (SRS) and software design specification (SDS), the verification of codes, the tests of the integrated software and system. Moreover, the software safety analysis and the software configuration management are involved in the DRPS V&V processes. All of the V&V activities are described, in detail, in this paper.

• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2151-2161
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• 2020

The study presents a review of research advancements in the field of gamma radiation detection systems for emergency radiation monitoring, particularly two major sub-systems namely (i) the radiation detector and (ii) the detection platform - air-borne and ground-based. The dynamics and functional characteristics of modern radiation detector active materials are summarized and discussed. The capabilities of both ground-based and aerial vehicle platforms employed in gamma radiation monitoring are deliberated in depth.

• Journal of the Society of Disaster Information
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• v.3 no.1
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• pp.55-68
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• 2007

Recently, people in cities of developed countries are exposed to unfortified damages of crime and disaster due to urbanization, industrialization and information-oriented era caused by congestion of population in terms of hardware and various social pathology phenomena and frequent and large scale of disaster caused by crime and disorder, which occur in the course of going through nuclear family, a gap between rich and poor and aging society in terms of software. In this regard, demand for security upon individual life and property has been increased but the police that are responsible for the public security does not effectively reduce damage in life and property because their activities are mainly oriented in coping with security accidents more than prevention. Shortage of manpower and budget, retarded equipment, and heavy overwork are the reasons. In order to confront with this kind of situation, we should utilize CCTV system with the purpose of declining possible chances of crime, not for eliminating cause of crime as crime prevention activities to predict danger in advance as a way of prevention and we may expect a role of damage prevention by installing CCTV in places where security accident may possibly happen. In conclusion, there are invasion of privacy, misuse of the system, insufficiency of overall monitoring office management, lack of citizens' understanding and economical allotment of the system installation costs in installation of CCTV system. However. it is necessary to install the CCTV system for effective prevention of crime and prevention activities of security accidents and accurate PR of purposes of installing CCTV to local residents, establishing relevant laws about system misuse, allotment of equipment costs and fees by R&D of the system machinery, cost reduction method of storage, management and replacement, saving costs from co-operative attitude of government, and local autonomous entities and local residents should be involved.