• Journal of the Korean Society of Safety
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• v.34 no.5
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• pp.167-174
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• 2019

Compared to a single nuclear power plant (NPP) risk, the commonalities existing in the multiple NPPs attribute the characteristics of the multi-unit risk. If there is no commonality among the multiple NPPs, there will be no dependency among the risks of multiple NPPs. Therefore, understanding the commonality causing multi-unit events is essential to assessing the multi-unit risk, and identifying the characteristics of the multi-unit risk is necessary not only to select the scope and method for the multi-unit risk assessment, but also to analyze the data of the multi-unit events. In order to develop Korea-specific multi-unit risk assessment technology, we analyze the multi-unit commonalities included in the operational experiences of domestic NPPs. We identified 58 cases of multi-unit events through detailed review of domestic nuclear power plant event reports over the past 10 years, and the multi-unit events were classified into six commonalities to identify Korea-specific characteristics of multi-unit events. The identified characteristics can be used to understand and manage domestic multi-unit risks. It can also be used as a basis for modeling multi-unit events for multi-unit risk assessment.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.541-551
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• 2020

Based on the trend, there have been numerous researches analysing the ship collision risk. However, in this scope, the navigational conditions and external environment are ignored or incompletely considered in training or/and real situation. It has been identified as a significant limitation in the navigational collision risk assessment. Therefore, a novel algorithm of the ship navigational collision risk solving system has been proposed based on basic collision risk and vulnerabilities of marine accidents. The vulnerability can increase the possibility of marine collision accidents. The factors of vulnerabilities including bad weather, tidal currents, accidents prone area, traffic congestion, operator fatigue and fishing boat operating area are involved in the fuzzy reasoning engines to evaluate the navigational conditions and environment. Fuzzy logic is employed to reason basic collision risk using Distance to Closest Point of Approach (DCPA) and Time of Closest Point of Approach (TCPA) and the degree of vulnerability in the specific coastal waterways. Analytical Hierarchy Process (AHP) method is used to obtain the integration of vulnerabilities. In this paper, vulnerability factors have been proposed to improve the collision risk assessment especially for non-SOLAS ships such as coastal operating ships and fishing vessels in practice. Simulation is implemented to validate the practicability of the designed navigational collision risk solving system.

• Journal of Environmental Policy
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• v.14 no.1
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• pp.53-83
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• 2015

Recently, climate change risk assessment has been discussed as a medium process for making climate change adaptation policies in the research field of climate change adaptation. Climate change risk assessment has been understood to have an intermediary role among impact assessment, vulnerable assessment and policy, and is used in the process of devising adaptation policies in the United Kingdom (UK). This paper quantitatively assessed the risks of climate change in Korea, applied the methods used in the UK, underwent the classification process and suggested implications of Korean adaptation policies. A survey of experts, based on Delphi's method and the classification criterion developed by Klinke and Renn(2002), was also carried out. A list of climate risks was created from the climate change impact and vulnerability assessment report of Korea, first national adaptation policy of Korea, and general climate risks of the UK. From the results, 42 risks out of total 125 risks were selected based on their importance. The assessed risks with factors, such as high impact and urgency, are related to repeated and large scale damage from storms and floods caused by abnormal or extreme weather events. Ecological changes and social infrastructure risks were engaged as required as a policy response for medium to longer term. As for making the classification, types of climate risks were suggested to manage the basic capacity in relation to social trust, triggering mechanism and responsibility. Following suggestions are put forward as the base of autonomous adaptation: increasing the capacity of civil society, mutual trust and civil participation in adaptation policy process.

• Korean Journal of Construction Engineering and Management
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• v.19 no.5
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• pp.81-89
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• 2018

The purpose of this study is to assess the risk and predict the contingency for modular plant construction projects. Considering the work characteristics of the modular plant, The adapted research method is that suggest models for assessment impact of risk and predict the contingency considering risk. Based on the proposed models, It is selected one modular plant construction project and assessment impact of risk factors and predicted the contingency. The results of this study are as follows: Assessment the probability of occurrence of risk factors and intensity of impact, and extract 15 important risk factors. These are classified as Engineering, Procurement, Fabrication, Transportation, Construction phases to consider the work characteristics of the modular plant. The predicted contingency is that 6.739%(Engineering 2.850%, Procurement 6.225%, Fabrication 6.211%, Transportation 4.165%, Construction 8.168%) to prepare the basic business expense. The model is used as a way to derive quantitative results in the decision-making process for risk management in construction projects.

• Journal of the Korean Society of Safety
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• v.38 no.3
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• pp.102-109
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• 2023

Following the accident at Fukushima, the true impact of multi-unit accidents came to light. Accordingly, research related to multi-unit accident effect analysis, risk evaluation, and accident prevention/prevention technology has been conducted. Specific examples are mobile/fixed equipment such as multi-barrier accident coping strategy (MACST) and diverse and flexible coping strategies (FLEX), which have been introduced and installed in multi-units for preventing and mitigating multi-unit accidents. These strategies are useful for enhancing the safety of nuclear power plants (NPPs); however, a more efficient strategy is required in terms of the costs of physical and human resources. To effectively and efficiently mitigate an increase in multi-unit accidents, it is necessary to not only to utilize mobile/fixed equipment but to also use crosstie options with resources that already exist at NPPs. Therefore, we analyzed the current international and domestic status of crosstie systems technology and propose a method to evaluate feasibility alongside risk based on a multi-unit probabilistic safety assessment (PSA). To analyze the international and domestic status of crosstie systems technology, actual cases and related research were studied, and a list of potential crosstie safety resources was derived. Additionally, a case study was performed on crosstie cases of two systems within the assumed six units on-site under a multi-unit accident, and a multi-unit PSA-based risk evaluation method is proposed.

• Journal of Korean Society of Disaster and Security
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• v.15 no.4
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• pp.57-69
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• 2022

During the 10 years from 2011 to 2021, a whopping 2,800 people were killed or injured during port work. Among them, the frequency of occurrence at the port loading and unloading business is high. Container terminal operators must conduct risk assessments and establish reasonable safety measures in accordance with laws and regulations. As a research method, the contents of risk assessment presented in the Industrial Safety and Health Act, the Serious Accident Punishment Act, and the Special Act on Port Safety are presented through literature analysis. In this study, previous studies were analyzed to examine the risk assessment method and risk factors of container terminals. The purpose is to present 'industrial safety AI chatbot technology' that can improve the risk of safety accidents.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.4
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• pp.307-319
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• 2010

As we learned in Daegu subway fire accident, fire in the railway tunnel is prone to develop to large disaster due to the limitation of smoke control and smoke exhaust. In railway tunnel, in order to ensure fire safety, fire prevention and fighting systems are installed by quantitative risk assessment results. Therefore, in this research, developed the program to establish quantitative risk assessment and suggested quantitative safety assessment method including fire scenarios in railway tunnel, fire and evacuation analysis model, fatality estimate model and societal risk criteria. Moreover, this method applys to plan preventing disaster for Honam high speed railway tunnel. As results, we presented the proper distance of escape route and societal risk criteria.

• Transactions of the Korean hydrogen and new energy society
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• v.35 no.1
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• pp.66-74
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• 2024

This study addresses the escalating issue of worldwide hydrogen gas accidents, which has seen a significant increase in occurrences. To comprehensively evaluate the risks associated with hydrogen, a two approach was employed in this study. Firstly, a qualitative risk assessment was conducted using the bow-tie method. Secondly, a quantitative consequence analysis was carried out utilizing the areal locations of hazardous atmospheres (ALOHA) model. The study applied this method to two incidents, the hydrogen explosion accident occurred at the Muskingum River power plant in Ohio, USA, 2007 and the hydrogen storage tank explosion accident occurred at the K Technopark water electrolysis system in Korea, 2019. The results of the risk assessments revealed critical issues such as deterioration of gas pipe, human errors in incident response and the omission of important gas cleaning facility. By analyzing the cause of accidents and assessing risks quantitatively, the effective accident response plans are proposed and the effectiveness is evaluated by comparing the effective distance obtained by ALOHA simulation. Notably, the implementation of these measures led to a significant 54.5% reduction in the risk degree of potential explosions compared to the existing risk levels.

• Environmental Analysis Health and Toxicology
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• v.17 no.2
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• pp.147-160
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• 2002

Volatile organic compounds (VOCs) are an important public health issue in Korea and many important questions remain to be addressed with respect to assessing exposure to these compounds. Because they are ubiquitous and highly volatile, special techniques must be applied in their analytic determination Valid Personal exposure assessment methods are needed to evaluate exposure frequency, duration and intensity, as well as their relationship to personal exposure characteristics. Biological monitoring is also important since it may contribute significantly in risk assessment by allowing the estimation of effective absorbed doses. This study was on ducted to establish the environmental measurement, personal dosimetry and biological monitoring methods for VOCs. These methods are needed to compare blood, urinary and exhalation breath VOC levels and to provide tools for risk assessment of VOC exposure. Passive monitors (badge type) and a active samplers (trap) for the VOCs collection were used for air sampling. Methods development included determining the minimum detectable amounts of VOCs in each media, as well as evaluating collection methods and developing analytical procedures. Method reliability was assessed by determining breakthrough volumes and comparing results between laboratories and with other methods. A total capacity of trap used in this study was 60ι. Although variable by compound, the average breakthrough was 20％. Also, there was no loss of compounds in trap even if keep for 45 day in -7$0^{\circ}C$. The recovery of active and passive methods was 69％ ~ 126％ and method detection limit was 0.24 $\mu\textrm{g}$/trap and 0.07 $\mu\textrm{g}$/badge. There was no statistical difference (P > 0.05) between active and passive methods.

• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.629-636
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• 2010

According to the spatial movements of the Nak-dong river watershed, the changes in heavy metal concentrations were simulated by WASP7.3. The risk assessment was performed using the predicted data of WASP7.3. The target heavy metal was manganese (Mn). In the simulated manganese data of WASP7.3, the average concentration by regions was from 0.03 mg/L to 0.07 mg/L. It is lower than drinking water standard in korea. The risk assessment was presented that it was high at the junction of Nak-dong river and Kumho river. It was influenced by the discharge of industrial complexes and large cities which were located in the junction. In comparison of drinking water standard and predicted data of WASP7.3 risk assessment, whole watershed was also low level at predicted data. However, to keep the similar risk value ($10^{-7}$) in adults and children anywhere, it requires the additional treatment of the point source discharges. It was also reflected by regions. Through this study, it was possible to evaluate heavy metal influence in unattainable monitoring regions and to estimate heavy metal addition and reduction by locations. Therefore, the outcomes of WASP7.3 can connect with the risk assessment and it can evaluate the safety of human by regions.