• Environmental Engineering Research
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• v.13 no.2
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• pp.73-78
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• 2008

For a given soil-contaminated site, a level of soil contamination is characterized and decisions on risk may be made from the risk assessment. The study evaluated critical design factors for the determination of sample size in the sampling design plan and the assessment of soil contaminant- leaching to groundwater. Two variables, the minimum relative detectable difference (T) and coefficient of variation (CV) were evaluated for the sample size determination. The minimum number of samples can be appropriately determined by CV under a T value greater than or equal to 0.2. Soil-contaminant leaching to groundwater was evaluated by using the Soil Screening Level equation of U.S. Environmental Protection Agency and the Risk Based Screening Level equation of American Society for Testing and Materials, with the same input parameters. The groundwater concentrations estimated from soil contaminant concentrations were significantly affected by the Darcy velocity of groundwater and the organic content of soil.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1234-1245
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• 2018

The risk of multi-unit nuclear power plants (NPPs) at a site has received considerable critical attention recently. However, current probabilistic safety assessment (PSA) procedures and computer code do not support multi-unit PSA because the traditional PSA structure is mostly used for the quantification of single-unit NPP risk. In this study, the main purpose is to develop a multi-unit Level 2 PSA method and apply it to full-power operating six-unit OPR1000. Multi-unit Level 2 PSA method consists of three steps: (1) development of single-unit Level 2 PSA; (2) extracting the mapping data from plant damage state to source term category; and (3) combining multi-unit Level 1 PSA results and mapping fractions. By applying developed multi-unit Level 2 PSA method into six-unit OPR1000, site containment failure probabilities in case of loss of ultimate heat sink, loss of off-site power, tsunami, and seismic event were quantified.

• Nuclear Engineering and Technology
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• v.44 no.5
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• pp.459-470
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• 2012

From the PSA point of view, the Fukushima accident of Japan in 2011 reveals some issues to be re-considered and/or improved in the PSA such as the limited scope of the PSA, site risk, etc. KAERI (Korea Atomic Energy Research Institute) has performed researches on the development of an integrated risk assessment framework related to some issues arisen after the Fukushima accident. This framework can cover the internal PSA model and external PSA models (fire, flooding, and seismic PSA models) in the full power and the low power-shutdown modes. This framework also integrates level 1, 2 and 3 PSA to quantify the risk of nuclear facilities more efficiently and consistently. We expect that this framework will be helpful to resolve the issue regarding the limited scope of PSA and to reduce some inconsistencies that might exist between (1) the internal and external PSA, and (2) full power mode PSA and low power-shutdown PSA models. In addition, KAERI is starting researches related to the extreme external events, the risk assessment of spent fuel pool, and the site risk. These emerging issues will be incorporated into the integrated risk assessment framework. In this paper the integrated risk assessment framework and the research activities on the emerging issues are outlined.

• Safety and Health at Work
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• v.2 no.3
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• pp.260-272
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• 2011

Objectives: The promotion of health and safety (H&S) awareness among hospital staff can be applied through various methods. The aim of this study was to assess the risk level of physical hazards in the hospital sector by combining workers' perception, experts' evaluation and objective measurements. Methods: A cross-sectional study was designed using multiple triangulation. Hospital staff (n = 447) filled in an H&S questionnaire in a general hospital in Athens and an oncology one in Thessaloniki. Experts observed and filled in a checklist on H&S in the various departments of the two hospitals. Lighting, noise and microclimate measurements were performed. Results: The staff's perception of risk was higher than that of the experts in many cases. The measured risk levels were low to medium. In cases of high-risk noise and lighting, staff and experts agreed. Staff's perception of risk was influenced by hospital's department, hospital's service, years of working experience and level of education. Therefore, these factors should be taken into account in future studies aimed at increasing the participation of hospital workers. Conclusion: This study confirmed the usefulness of staff participation in the risk assessment process, despite the tendency for staff to overestimate the risk level of physical hazards. The combination of combining staff perception, experts' evaluation and objective measures in the risk assessment process increases the efficiency of risk management in the hospital environment and the enforcement of relevant legislation.

• International Journal of Safety
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• v.6 no.2
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• pp.8-12
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• 2007

This study includes a case study among plastic process manufacturing companies, based on which, the currently used 4M method is applied in terms of machine, media, man, and management, to conduct quantitative risk evaluation, and thus to contribute to reducing human and material loss as well as preventing accidents in industrial fields. The result of this study is analyzed based on the 4M-risk assessment to find out the hazardous risk elements, and the quantitative evaluation made it predictable the value of risk(frequency $\times$ intensity) in such classified levels as serious risk, critical risk, and intolerable risk. Further, Among the businesses with hazardous risk elements and high frequency of industrial disaster, risk analysis was conducted for each process, and as a result, 38 cases among 76, including those of serious risk, critical risk, and intolerable risk, were improved, and the risk was reduced. Besides, it is thought that with the engineering approach with 4M-Risk Assessment, the attempt to improve safety level contributes to prevention of accidents.

• Environmental Analysis Health and Toxicology
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• v.31
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• pp.11.1-11.6
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• 2016

Objectives A hazard assessment of di(2-ethylhexyl) phthalate (DEHP), a commonly used workplace chemical, was conducted in order to protect the occupational health of workers. A literature review, consisting of both domestic and international references, examined the chemical management system, working environment, level of exposure, and possible associated risks. This information may be utilized in the future to determine appropriate exposure levels in working environments. Methods Hazard assessment was performed using chemical hazard information obtained from international agencies, such as Organization for Economic Cooperation and Development-generated Screening Information Data Set and International Program on Chemical Safety. Information was obtained from surveys conducted by the Minister of Employment and Labor ("Survey on the work environment") and by the Ministry of Environment ("Survey on the circulation amount of chemicals"). Risk was determined according to exposure in workplaces and chemical hazard. Results In 229 workplaces over the country, 831 tons of DEHP have been used as plasticizers, insecticides, and ink solvent. Calculated 50% lethal dose values ranged from 14.2 to 50 g/kg, as determined via acute toxicity testing in rodents. Chronic carcinogenicity tests revealed cases of lung and liver degeneration, shrinkage of the testes, and liver cancer. The no-observed-adverse-effect level and the lowest-observed-adverse-effect level were determined to be 28.9 g/kg and 146.6 g/kg, respectively. The working environment assessment revealed the maximum exposure level to be $0.990mg/m^3$, as compared to the threshold exposure level of $5mg/m^3$. The relative risk of chronic toxicity and reproductive toxicity were 0.264 and 0.330, respectively, while the risk of carcinogenicity was 1.3, which is higher than the accepted safety value of one. Conclusions DEHP was identified as a carcinogen, and may be dangerous even at concentrations lower than the occupational exposure limit. Therefore, we suggest management of working environments, with exposure levels below $5mg/m^3$ and all workers utilizing local exhaust ventilation and respiratory protection when handling DEHP.

• Journal of Korean Society on Water Environment
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• v.25 no.4
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• pp.494-501
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• 2009

Probabilistic Ecological risk assessment (PERA) is extensive approach to qualify and quantify risk on the multi species based on species sensitivity distribution (SSD). As a while, deterministic ecological risk assessment (DERA) considers the comparison of predicted no-effect concentration (PNEC) and predicted exposure concentration (PEC). DERA is used to determine if there is potential risk or no risk, and it doesn't consider the nature variability and the species sensitivity. But PERA can be more realistic and reasonable approach to estimate likelihood or risk. In this study, we compared PERA used in developed countries, and proposed PERA applicable for the Korean water environment. Taxonomic groups were classified as "class" level including Actinopterygill, Branchiopoda, Chlorophyceae, Maxillapoda, Insects, Bivalvia, Gastropoda, Secernentea, Polychaeta, Monocotyldoneae, and Chanophyceae in this study. Statistical extrapolation method (SEM), statistical extrapolation method $_{acutechronicratio}$ ($SEM_{ACR}$) and assessment factor method (AFM) were used to calculate the ecological protective concentration based on qualitative and quantitative levels of taxonomic toxicity data. This study would be useful to establish the PERA for the protection of aquatic ecosystem in Korea.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.275-280
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• 2008

Recently the railway safety is very important issue in Korea because there are lots of changes like the separation of operation and facility of national rail network, the inauguration of high speed train and Daegu subway fire accident. Railway safety management system is based on risk assessment of rolling stocks, electrical system, signaling, operation & maintenance and human element. With this process, railway risk will be reduced as low as reasonably acceptable level. Through risk assessment on accident data, this study predicted the current risk level of railway electrical system and presented the proper safety ensuring measures.

• Journal of the Korea Safety Management & Science
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• v.16 no.2
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• pp.63-70
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• 2014

As preventive measures have received tremendous attention to prevent any possible accident in advance, many work places have introduced safety and health management systems. However despite of this government's effort, the industrial accident rate of small-scale businesses with less than 50 employees does not decline, which is mainly because the projects are not differentiated according to the risk level of individual business. To evaluate the risk level of small-scale businesses with less than 50 employees and then establish effective safety and health management systems according to the risk level, this study has conducted the following processes. The small-scale businesses with less than 50 employees were evaluated through accident type, and potential accident risk factor was evaluated through location, business type, and business size. The results of this analysis are expected to make contribution to improving the effectiveness of the safety and health management supports to small-scale businesses with less than 50 employees.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.3
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• pp.263-274
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• 2024

The digitization of ship environments has increased the risk of cyberattacks on ships. The smartization and automation of ships are also likely to result in cyber threats. The International Maritime Organization (IMO) has discussed the establishment of regulations at the autonomous level and has revised existing agreements by dividing autonomous ships into four stages, where stages 1 and 2 are for sailors who are boarding ships while stages 3 and 4 are for those not boarding ships. In this study, the level of a smart ship was classified into LEVELs (LVs) 1 to 3 based on the autonomous levels specified by the IMO. Furthermore, a risk assessment for smart ships at various LVs in different risk scenarios was conducted The cyber threats and vulnerabilities of smart ships were analyzed by dividing them into administrative, physical, and technical security; and mitigation measures for each security area were derived. A total of 22 cyber threats were identified for the cyber asset (target system). We inferred that the higher the level of a smart ship, the greater the hyper connectivity and the remote access to operational technology systems; consequently, the greater the attack surface. Therefore, it is necessary to apply mitigation measures using technical security controls in environments with high-level smart ships.