• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1336-1342
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• 2022

Risk-informed safety classification of structures, systems and components (SSCs) is very important for ensuring the safety and economic efficiency of nuclear power plants (NPPs). However, previous methods for safety classification of SSCs do not take the plant operating modes or the operational process of SSCs into consideration, thus cannot concentrate on the safety and economic efficiency accurately. In this contribution, a new method for safety classification of SSCs based on the categorization of plant operating modes is proposed, which considers the NPPs operating history to improve the economic efficiencies while maintaining the safety. According to the time duration of plant configurations in plant operating modes, average importances of SSCs are accessed for an NPP considering the operational process, and then safety classification of SSCs is performed for plant operating modes. The correctness and effectiveness of the proposed method is demonstrated by application in an NPP's safety classification of SSCs.

• Journal of Navigation and Port Research
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• v.34 no.4
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• pp.287-292
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• 2010

The purpose of this study was to create a cyber-training & education program in response to the needs of skippers and crews operating tug-barges within Korean coastal waters and the rapid changers in this industry. Skippers and crews are inclined to operate tug-barges on the basis of experience rather than information. It is not easy to provide useful information whenever they want or to drill them in safety management skills, because of their passive attitude toward education and the few opportunities that exist. In order to increase educational opportunities, efficiency and motivation, the authors have developed this program which consists of a 'tug bridge resource management module, risk perception training module, accident case module, operating module and navigation module', and are hoping that this program will enhance and strengthen all tug-barge operations. We are also putting all our energies into designing up to date animation programs and developing new scenarios concerning the method of evaluation and certification distribution.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.1
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• pp.40-50
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• 2013

This study is aimed to find a control factor for the marine casualty of fishing vessel by using the risk quantitative method of marine casualty, and sequentially timed event analysis for the reason finding. The result is that collision, sinking, and capsizing took high risk need to be strongly controlled. And the accident reason and control factors distinguished are as follows. The 82.2% of collided fishing vessels have negligence of look out as a immediate cause, while it was judged that underlying causes were the characteristics of vessels and fishing method, lack of suitable complement, fatigue, the prejudice or ignorance on steering and sailing rules. So the control factors are; firstly needs educational control measures and in terms of systemic control approach expand the range of the certificate of competency more smaller tonnage.

• Journal of the Korean Society of Safety
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• v.26 no.5
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• pp.46-53
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• 2011

The risk assessment of thermal behavior and runaway reaction cased by an exothermic batch process in manufacture of the vinyl acetate resin are described in the present paper. The aim of the study was to evaluate the risk of runaway reaction with operating parameters such as a reaction inhibitor, reaction temperature and a mount of methanol charged in the vinyl acetate polymerization process. The experiments were performed by a sort of calorimetry with the Multimax reactor system as a screening tool to investigate runaway reaction. From the experimental results, it was found that we could occur the auto acceleration for reaction of raw materials with operating parameters over $65^{\circ}C$ of reaction temperature in the vinyl acetate polymerization process.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.2
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• pp.437-441
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• 2012

Objective: Health risk appraisal is often utilized to modify individual's health behavior, especially concerning disease prevention, and web-based health risk appraisal services are being provided to the general public in Korea. However, little is known about the psychological effect of the health risk appraisal even though poorly communicated information by the web-based service may result in unintended adverse health outcomes. This study was conducted to explore the psychological effect of health risk appraisal using epidemiological risk factor profile. Methods: We conducted a randomized trial comparing risk factor list type health risk appraisal and risk score type health risk appraisal. We studied 60 women aged 30 years and older who had no cancer. Anxiety level was assessed using the Spielberger State-Trait Anxiety Inventory YZ. Results: The results of multivariate analysis showed that risk status was the independent predictors of increase of state anxiety after health risk appraisal intervention when age, education, health risk appraisal type, numeracy, state anxiety, trait anxiety, and health risk appraisal type by risk status interaction was adjusted. Women who had higher risk status had an odd of having increased anxiety that was about 5 times greater than women who had lower risk status. Conclusions: Our findings indicate that communicating the risk status by individual health risk appraisal service can induce psychological sequelae, especially in women having higher risk status. Hospitals, institutes, or medical schools that are operating or planning to operate the online health risk appraisal service should take side effects such as psychological sequelae into consideration.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.598-603
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• 2003

During the last ten years, the need has been increased for reducing maintenance cost for aged equipments and ensuring safety, efficiency and profitability of petrochemical and refinery plants. RBI (Risk Based Inspection) methodology is one of the most promising technologies satisfying the need in the field of integrity management. In this study, a user-friendly software, realRBI for RBI based on the API 581 code was developed and a quantitative analysis was performed for over 500 equipments in a domestic plant whose operating time reaches about 13 years. Current risks for each equipment parts were evaluated and risk based prioritization were determined as a conclusion.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.44-51
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• 2001

To account for uncertainties involved in an economic analysis of project, sensitivity analysis are usually being done in Korea. Though useful for policy analysis, but it larks explicit consideration of probability of occurring certain events considered in the sensitivity analysis. Risk analysis otherwise can explicitly account for the probability of certain event which has dire impact on project viability, such as cost, discount rate, and size of benefit. This paper reports experience of applying risk analysis method for economic evaluation of railroad investment. Probability distribution of event has paramount impact on the risk analysis results, while not many prior researches dealt with these issues. Probability distribution of rolling stock cost and operating cost, in addition to those cost variables, are developed considering railway demand in this study. Case study results are reported. Issues in applying risk analysis are reported in addition to further research direction.

• Journal of the Korean Society of Safety
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• v.35 no.3
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• pp.72-78
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• 2020

The accident fatality rate has decreased by more than 90% compared to 2006, due to the safety management and safety investment based on the Rail Safety Act. Most railway safety indicators, including fatality rates, have improved significantly from 60% to 80%, reaching the level of developed countries in terms of most railway safety indicators. However, the only staff fatality rate at work is not improved, and it is 3 to 5 times higher than that of developed countries. Most of the fatality occurred during employee's work recently occurred due to accidents hit by train while track work. In principle, when operating track need to check or maintenance, the operation of the train should be stopped and the work carried out. However, in Korea, due to the highest passenger density and train operating density in the world, it is caused by a structural problem that requires workers to enter the track while the train is running and perform various tasks such as maintenance and inspection. In this study, we analyzed the risk of accidents caused by hit by trains on the track, which is the biggest cause of staff fatality, using the main statistics of the last 10 years. In detail, the scenarios of the main causes of hit by trains and workers were formed to suggest the effectiveness of the current preventive measures and supplementary.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.1
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• pp.347-352
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• 2016

Background: This study used receiver operating characteristic curve to analyze Surveillance, Epidemiology and End Results (SEER) adenosquamous carcinoma data to identify predictive models and potential disparities in outcome. Materials and Methods: This study analyzed socio-economic, staging and treatment factors available in the SEER database for adenosquamous carcinoma. For the risk modeling, each factor was fitted by a generalized linear model to predict the cause specific survival. An area under the receiver operating characteristic curve (ROC) was computed. Similar strata were combined to construct the most parsimonious models. Results: A total of 20,712 patients diagnosed from 1973 to 2009 were included in this study. The mean follow up time (S.D.) was 54.2 (78.4) months. Some 2/3 of the patients were female. The mean (S.D.) age was 63 (13.8) years. SEER stage was the most predictive factor of outcome (ROC area of 0.71). 13.9% of the patients were un-staged and had risk of cause specific death of 61.3% that was higher than the 45.3% risk for the regional disease and lower than the 70.3% for metastatic disease. Sex, site, radiotherapy, and surgery had ROC areas of about 0.55-0.65. Rural residence and race contributed to socioeconomic disparity for treatment outcome. Radiotherapy was underused even with localized and regional stages when the intent was curative. This under use was most pronounced in older patients. Conclusions: Anatomic stage was predictive and useful in treatment selection. Under-staging may have contributed to poor outcome.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1307-1313
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• 2019

Recent analysis results with realistic assumptions provide the variability of operator allowable time for the initiation of aggressive cooldown under small break loss of coolant accident or steam generator tube rupture with total failure of high pressure safety injection. We investigated how plant risk may vary depending on the variability of operators' failure probability of timely initiation of aggressive cooldown. Using a probabilistic safety assessment model of a nuclear power plant, we showed that plant risks had a linear relation with the failure probability of aggressive cooldown and could be reduced by up to 10% as aggressive cooldown is more reliably performed. For individual accident management, we found that core damage potential could be gradually reduced by up to 40.49% and 63.84% after a small break loss of coolant accident or a steam generator tube rupture, respectively. Based on the importance of timely initiation of aggressive cooldown by main control room operators within the success criteria, implications for improvement of emergency operating procedures are discussed. We recommend conducting further detailed analyses of aggressive cooldown, commensurate with its importance in reducing risks in nuclear power plants.