• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.11 no.3
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• pp.207-212
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• 2013

Since the Fukushima nuclear power plant accident in March 2011, critical views on the increase in operation of nuclear power plants including the safety and the economic feasibility thereof have been expanding across the world. In these circumstances, we are to find out solutions to the controversial questions on whether nuclear power plants are economically more feasible than other energy sources, while the safety thereof is fully maintained. Thereby, nuclear power plants will play a key role as a sustainable energy source in the future as well as at present. To measure the social safety level that Korean people are actually feeling after the Fukushima accident, a method of cost-benefit analysis called the Contingent Valuation Method(CVM) was used, whereby we wanted to estimate the amount of expenses the general public would be willing to pay for the safety based on their acceptance rather than the social safety. As a result of calculating the trade-off value of the economic feasibility versus the safety in nuclear power plants through the survey thereon, it caused the nuclear power generation cost to be increased by 4.75 won/kWh. Reflecting this on the current power generation cost of 39.11 won/kWh would increase the cost to 43.86 won/kWh. It is thought that this potential cost is still more competitive than the coal-fired power generation cost of 67 won/kWh. This result will be available as a basic data for the 2nd Energy Basic Plan to be drawn up this year, presenting policy implications at the same time.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.981-988
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• 2023

A seismic event caused an accident at the Fukushima Nuclear Power Plant, which further resulted in simultaneous accidents at several units. Consequently, this incident has aroused great interest in the safety of nuclear power plants worldwide. A reasonable safety evaluation of such an external event should appropriately consider the correlation between SSCs (structures, systems, and components) and the probability of failure. However, a probabilistic safety assessment in current nuclear industries is performed conservatively, assuming that the failure correlation between SSCs is independent or completely dependent. This is an extreme assumption; a reasonable risk can be calculated, or risk-based decision-making can be conducted only when the appropriate failure correlation between SSCs is considered. Thus, this study analyzed the effect of the failure correlation of SSCs on the safety of the system to realize rational safety assessment and decision-making. Consequently, the impact on the system differs according to the size of the failure probability of the SSCs and the AND and OR conditions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.230-231
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• 2018

Recently, the danger for radioactive materials has become a hot topic. Beginning with the Chernobyl nuclear accident in 1996, in 2011, the Fukushima nuclear power plant in Japan suffered major damage such as large-scale casualties and radioactive dangerous area selection. Concerns about leakage of radioactive materials due to recent earthquakes have been deepening in Korea, such as Wolsong Nuclear Power Plant in Gyeongju, and there is a growing interest in the safety of radioactive materials through the media and the media. However, the route to exposure to radioactive materials is not limited to these large-scale nuclear accidents. Typical examples of this are radioactive substances exposed in daily life. In the case of radon gas, the danger is being revealed through current events programs and news, and natural radiation exposure is attracting attention.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.12 no.2
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• pp.66-70
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• 2016

Following the 2011 Fukushima Nuclear Power Plant accident, the IAEA has issued a revised version of the Nuclear Safety Standard for beyond design basis earthquake to consider the core meltdown accident. In Korea, relevant laws and regulations were also revised to consider beyond design basis earthquake to nuclear components. In this paper, CAV, an seismic damage factor that determines the restart of nuclear power plant after operating breakdown earthquake, is proposed for extension to the beyond design basis earthquake. For pipings not satisfying the beyond design basis earthquake condition, several evaluation methods are suggested, such as strain-based evaluation methods, simple nonlinear analysis method and cumulative damage evaluation method.

• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.967-973
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• 2021

In 2011, an earthquake and subsequent tsunami hit the Fukushima Daiichi Nuclear Power Plant, causing simultaneous accidents in several reactors. This accident shows us that if there are several reactors on site, the seismic risk to multiple units is important to consider, in addition to that to single units in isolation. When a seismic event occurs, a seismic-failure correlation exists between the nuclear power plant's structures, systems, and components (SSCs) due to their seismic-response and seismic-capacity correlations. Therefore, it is necessary to evaluate the multi-unit seismic risk by considering the SSCs' seismic-failure-correlation effect. In this study, a methodology is proposed to obtain the seismic-response-correlation coefficient between SSCs to calculate the risk to multi-unit facilities. This coefficient is calculated from a probabilistic multi-unit seismic-response analysis. The seismic-response and seismic-failure-correlation coefficients of the emergency diesel generators installed within the units are successfully derived via the proposed method. In addition, the distribution of the seismic-response-correlation coefficient was observed as a function of the distance between SSCs of various dynamic characteristics. It is demonstrated that the proposed methodology can reasonably derive the seismic-response-correlation coefficient between SSCs, which is the input data for multi-unit seismic probabilistic safety assessment.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.224-228
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• 2012

According to the results of Probabilistic Safety Assessment(PSA) for a Nuclear Power Plant(NPP), an Emergency Power Supply(EPS) system has been considered as one of the most important safety system. Especially, the interests in the reliability of the EPS system have been increased after the severe accidents of Fukushima Daiichi. Firstly, we performed the risk assessment and the importance analysis of the EPS system based on the PSA models of the reference plant, which is the Korean standard NPP type. Considering a portable Diesel Generator(DG) system as the reliability reinforcement of the EPS system, we modified the PSA models and performed the risk impact assessment and the importance analysis. Although the reliability of the potable DG could be about 20% of the reliability of the alternative AC DG, we identified that Core Damage Frequency(CDF) was decreased by at least 4.6%. In addition, the risk impacts due to the unavailability of the EPS system on CDF were decreased.

• Journal of Radiation Protection and Research
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• v.48 no.3
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• pp.107-116
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• 2023

This article reviews the experience of applying the Identification, Diagnosis, Prospective, and Action (IDPA) facilitating method as a means of promoting practices of dialogue between stakeholders in the radiological protection field. After presenting the characteristics of the IDPA method and its ability to promote active listening, participation, and dialogue among stakeholders facing complex situations, as well as the procedural aspects associated with its practical implementation, the article describes three examples of the application of the method in the field of radiological protection. The first one presents how the IDPA method supported a debate among decision-makers, authorities, experts, professionals, and representatives of non-governmental organizations about how to engage stakeholders in radiological protection. The second example presents how the IDPA method was used in a series of dialogue meetings to explore the challenges of the post-nuclear accident situation resulting from the Fukushima Daiichi Nuclear Power Plant accident. The third one presents the application of the method in the context of a training course organized by Nagasaki University in the affected area close to the damaged plant. Experience has shown that the IDPA method makes it possible to develop responses to problems posed in very different contexts and, in many cases, to find compromises regarding their solutions. The IDPA method has the merit of allowing each of the participants to better understand the situation they are faced with, even if such a positive result is not always achieved.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.4
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• pp.231-236
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• 2011

When the Fukushima nuclear power plant accident occurred in March of 2011, a hydrogen explosion in the reactor building at the 4th unit of Fukushima plants led to a big surprise because the full core of the unit 4 reactor had been moved and stored underwater at the spent nuclear fuel storage pool for periodic maintenance. It was because the possible criticality in the fuel storage pool by coolant loss may yield more severe situation than the similar accident happened inside the reactor vessel. Fortunately, it was assured to be evitable to an anxious situation by a look of water filled in the storage pool later. In the paper, the safety state of the spent fuel storage pool and rack structures of the domestic nuclear plants would be roughly reviewed and compared with the Fukushima plant case by engineering viewpoint of potential severe accidents.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.6
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• pp.415-421
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• 2013

In order to extend the service life of a nuclear power plant(NPP) ensuring the structural safety, effective and efficient management of NPP considering structural deteriorations and various natural hazard risks has been treated as a significant tool(IAEA 1998). The systemic efforts is required to prevent the potential loss of NPPs resulting from the natural hazard including earthquakes, hurricane and flooding since the Fukushima accident. Earthquake risk of building structures can be mitigated through appropriate seismic isolation system installation. It has been known that a seismic isolation system can lead to reduction of the deleterious effect on ground motion induced by earthquakes, and structural safety can be improved. In this paper, the NPP life-cycle management is reviewed. Furthermore, effect of seismic isolation on the NPP life-cycle cost analysis with earthquake, and cost-benefit analysis in terms of life-cycle cost when applying the seismic isolation systems to NPP are introduced.

• 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.