• 시스템엔지니어링학술지
• /
• 제18권2호
• /
• pp.58-74
• /
• 2022

Deterministic accident analysis plays a central role in the nuclear power plant (NPP) safety evaluation and licensing process. Traditionally the conservative approach opted for the point kinetics model, expressing the reactor core parameters in the form of reactivity and power tables. However, with the current advances in computational power, high fidelity multi-physics simulations using real-time code coupling, can provide more detailed core behavior and hence more realistic plant's response. This is particularly relevant for transients where the core is undergoing reactivity anomalies and uneven power distributions with strong feedback mechanisms, such as reactivity initiated accidents (RIAs). This work addresses a RIA, specifically a control element assembly (CEA) withdrawal at power, using the multi-physics analysis tool RELAP5/MOD 3.4/3DKIN. The thermal-hydraulics (TH) code, RELAP5, is internally coupled with the nodal kinetics (NK) code, 3DKIN, and both codes exchange relevant data to model the nuclear power plant (NPP) response as the CEA is withdrawn from the core. The coupled model is more representative of the complex interactions between the thermal-hydraulics and neutronics; therefore the results obtained using a multi-physics simulation provide a larger safety margin and hence more operational flexibility compared to those of the point kinetics model reported in the safety analysis report for APR1400. The systems engineering approach is used to guide the development of the work ensuring a systematic and more efficient execution.

• 대한안전경영과학회지
• /
• 제16권3호
• /
• pp.399-409
• /
• 2014

The purpose of this study includes: Firstly, to examine the effects of procedural justice and job significance on value of work, psychological ownership, and job satisfaction. Secondly, to examine the mediating effect of the value of work, psychological ownership on the relationship between procedural justice, job significance and job satisfaction. For the study, the data was collected from convenient sample of 273 nurses at university hospital in a city to test theoretical model and its hypotheses. All data collected from the survey were analyzed using with SPSS 18.0 and AMOS 18.0. This study reports findings as followed: first, the relationship between the procedural justice and the value of work is positively related. Second, there was also a positive correlation between the procedural justice and the psychological ownership. Third, there was also a positive correlation between the job significance and the value of work. Fourth, the relationship between the job significance and the psychological ownership is positively related. Fifth, there was also a positive correlation between the value of work and the psychological ownership. Sixth, there was also a positive correlation between the procedural justice and the job satisfaction. Seventh, the relationship between the job significance and the job satisfaction is positively related. Eighth, there was also a positive correlation between the value of work and the job satisfaction. Ninth, there was also a positive correlation between the psychological ownership and the job satisfaction. Finally, the value of work and psychological ownership played as a partial mediator on the relationship between procedural justice and job satisfaction. Also, the value of work and psychological ownership played as a partial mediator on the relationship between job significance and job satisfaction. Based on these findings, the limitations of the study and some directions for future studies were presented.

• 대한안전경영과학회지
• /
• 제17권3호
• /
• pp.247-263
• /
• 2015

This study seeks to identify effects derived from emotional labor in the distribution industry, and draw ways to systematically manage the employees by exploring effects of the emotion work on performance. For the purpose, literature reviews and empirical experiments were conducted to find out effects of emotional labor and false face acting on emotion work and organizational performance and effects of social support and job autonomy on the relationship between emotion work and organizational performance. To verify the hypothesis, we conducted a hierarchical regression analysis and structural equation model analysis using SPSS 20 and AMOS19. The result of the verification in this study is as follows: First, effects of emotional labor on burnout was found to be statistically significant, second, as for the path-coefficient for "emotional labor ${\rightarrow}$ emotion work" and "emotional labor ${\rightarrow}$ job satisfaction" was not statistically significant, while the path-coefficient for "emotional labor ${\rightarrow}$ service level" was found to be statistically significant. Third, effects of emotion work on job satisfaction was found statistically significant, fourth, emotion work on the service level was found statistically significant, fifth, effects of false face acting on emotion work was found statistically significant, sixth, effects of false face acting on burnout was statistically significant, seventh, moderating were found statistically significant and lastly, moderating effects of the relationship between emotion work from job autonomy and organization performance was not verified in job satisfaction, while emotion work, job autonomy, and interaction variable in service level were statistically significant.

• 대한토목학회논문집
• /
• 제31권5D호
• /
• pp.705-717
• /
• 2011

타워크레인은 건설현장의 전체 자재인양 중 약 50%의 물량을 인양하는 양중 장비로 그 수는 빠른 속도로 증가하고 있으나, 건설현장에서의 소홀한 안전관리로 타워크레인 관련 안전사고는 매년 지속적으로 발생되고 있는 실정이다. 특히, 텔레스코핑 작업은 타워크레인 설치단계에서 텔레스코핑 케이지를 유압으로 상승시킨 후 생긴 빈 공간에 새로운 마스트를 삽입하여 요구 높이까지 상승시키는 작업으로 고소에서 다수의 작업자가 동시에 작업을 실시하여 추락 및 낙하의 위험성이 존재하는 등 타 작업에 비해 재해사례 비중이 가장 높은 것으로 분석되었다. 본 연구의 목적은 타워크레인 작업 중 특히 위험성이 높은 것으로 조사 및 분석된 텔레스코핑 작업의 안전성 및 생산성을 향상시킬 수 있는 타워크레인 텔레스코핑 자동화기술의 개념모델을 제안하고 이에 대한 안전성 측면에서의 잠재적 성능을 분석함으로써 향후 타워크레인 텔레스코핑 자동화기술 실물 제작을 위한 원천자료를 제공하는 것이다.

• 한국안전학회지
• /
• 제10권3호
• /
• pp.81-95
• /
• 1995

Now, safety assurance in construction sites should be accomplished by its own organization rather than control of the code or government. It is believed that the safety assurance can be considerably improved by a lecture or an education using the existing theories or literatures up to now, but it is thought that fundamental safety assurance we not able to be accomplished without developing safety devices '||'&'||' equipment or taking fundamental measures, based on the result analyzed from workers behaviors. There are various behaviors of the workers showed in construction site, but only tests for hammerusing works such as form, re-bar, stone workers directly related to the grip strength are mainly performed, investigated and measured here for the study. The above works are similar to power grip, 7th picture on seven items which are categorized for hand grip types(Ammermin 1956 ; Jones ; Kobrick 1958). Measurements of grip strength are commonly taken in anthropometric surveys. They are easy to administer but unfortunately it is rather dubious whether they yield any data that are of interest to the engineer. Very fewer controls of tools are grasped and squeesed studies showed very little overall correlation between grip strength and other measures of bodily strength (Laubach, Kromer, and Thordsen 1972), but hammer-using work which is practically progressed in construction site are mainly influenced with grip strength. According to the investigation on work measurement, it is shown that 77% of form worker are using hammer to be related to grip strength. In this study, it is particularly noticed that wearing safety gloves in construction site is required for workers safety but 20% difference between grip strength with safety gloves and without ones are commonly neglected in the site(Fig. 1). Nevertheless, safety operation with consideration of the above 20% difference is not considered in the construction site. Factors of age, kinds of work, working time, with or without safety gloves are in vestigated '||'&'||' collected at the sites for this study. Test, not at each working hour but at 14 : 00 when the almost all of the workers think the most tired, resulting from the questionaires, also when it is shown on the research report has been performed and compared for main kinds of works : form '||'&'||' re-bar work. Tests were performed with both left SE rightand of the workers simultaneously in construction site using Rand Dynamometer(Model 78010, Lafayette Instrument Co., Indiana, U.S.A) by reading grip strength on the gauge while they are pulling, and then by interviewing on their ages, works, experiences and etc., directly. The above tests have been performed for the dates of 15th march-26th May '95 with consideration of site condition. And even if various factors of ambient temperature on the testing date, working condition, individual worker's habit and worker's condition of the previous ate are concerned with the study. Those are considered as constants in this study. Samples are formwork 53, rebar 62, electrician 5, plumber 4, welding 1 from D construction Co., Ltd, ; formwork 12, re-bar 5, electrician 2, from S construction Co., Ltd, , formwork 78, re-bar 18, plumber 31, electrician 13, labor 48, plumber 31, plasterer 15, concrete placer 6, water proof worker 3, maisony 5 from B construction Co., Ltd. As In the previously mentioned, main aspect to be investigated in this study will be from '||'&'||' re-bar work because grip strength will be directly applied to these two kinds of works ; form '||'&'||' re-bar work, eventhough there are total 405 samples taken. It is thought that a frequency of accident occurrence will be mainly two work postures "looking up '||'&'||' looking down" to be mainly sorted, but this factor is not clarified in this study because It will be needed a lot of work more. Tests has been done at possible large scale of horizontally work-extended sites within one hour in order to prevent or decrease errors '||'&'||' discrepancies from time lag of the test. Additionally, the statistical package computer program SPSS PC＋has been used for the study.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
• /
• pp.31-33
• /
• 2012

Movable scaffolding has been used to work in high places. The scaffolding is economical and convenient to move to other places, but it has the risk of falling down. This paper proposes a fixed bracing system to prevent the falling down of a movable scaffolding, and evaluates its usability by making a small-sized model. Further studies of structural stability, safety, and economical efficiency is necessary to use the system practically.

• Safety and Health at Work
• /
• 제8권2호
• /
• pp.189-197
• /
• 2017

Background: Despite the recent efforts to prevent industrial accidents in the Republic of Korea, the industrial accident rate has not improved much. Industrial safety policies and safety management are also known to be inefficient. This study focused on dynamic characteristics of industrial safety systems and their effects on safety performance in the Republic of Korea. Such dynamic characteristics are particularly important for restructuring of the industrial safety system. Methods: The effects of damping and elastic characteristics of the industrial safety system model on safety performance were examined and feedback control performance was explained in view of cost and benefit. The implications on safety policies of restructuring the industrial safety system were also explored. Results: A strong correlation between the safety budget and the industrial accident rate enabled modeling of an industrial safety system with these variables as the input and the output, respectively. A more effective and efficient industrial safety system could be realized by having weaker elastic characteristics and stronger damping characteristics in it. A substantial decrease in total social cost is expected as the industrial safety system is restructured accordingly. Conclusion: A simple feedback control with proportional-integral action is effective in prevention of industrial accidents. Securing a lower level of elastic industrial accident-driving energy appears to have dominant effects on the control performance compared with the damping effort to dissipate such energy. More attention needs to be directed towards physical and social feedbacks that have prolonged cumulative effects. Suggestions for further improvement of the safety system including physical and social feedbacks are also made.

• 한국안전학회지
• /
• 제36권5호
• /
• pp.86-91
• /
• 2021

Calculating the scrutable core damage frequency (CDF) of nuclear power plants is an important component of the seismic probabilistic safety assessment (SPSA). In this work, a simple approach is developed to calculate CDF from minimal cut sets (MCSs) with non-rare events. When conventional calculation methods based on rare event approximations are employed, the CDF of industry SPSA models is significantly overestimated by non-rare events in the MCSs. Recently, quantification algorithms using binary decision diagrams (BDDs) have been introduced to prevent CDF overestimation in the SPSA. However, BDD structures are generated from a small part of whole MCSs due to limited computational memory, and they cannot be reviewed due to their complicated logic structure. This study suggests a simple approach for scrutinizing the CDF calculation based on whole MCSs in the SPSA system analysis model. The proposed approach compares the new results to outputs from existing algorithms, which helps in avoiding CDF overestimation.

• Nuclear Engineering and Technology
• /
• 제50권8호
• /
• pp.1277-1288
• /
• 2018

In this work, the reactor kinetics capability is used to compute the design safety parameters in a PWR due to complete loss of coolant flow during protected and unprotected accidents. A thermal-hydraulic code coupled with a point reactor kinetic model are used for these calculations; where kinetics parameters have been developed from the neutronic SRAC code to provide inputs to RELAP5-3D code to calculate parameters related to safety and guarantee that they meet the regulatory requirements. In RELAP5-3D the reactivity feedback is computed by both separable and tabular models. The results show the importance of the reactivity feedback on calculating the power which is the key parameter that controls the clad and fuel temperatures to maintain them below their melting point and therefore prevent core melt. In addition, extending modeling capability from separable to tabular model has nonremarkable influence on calculated safety parameters.

• Safety and Health at Work
• /
• 제11권4호
• /
• pp.431-442
• /
• 2020

Background: Psychosocial risks are increasingly a type of risk analyzed in organizations beyond chemical, physical, and biological risks. To this type of risk, a greater attention has been given following the update of ISO 9001: 2015, more precisely the requirement 7.1.4 for the process operation environment. The update of this normative reference was intended to approximate OHSAS 18001: 2007 reference updated in 2018 with the publication of ISO 45001. Thus, the organizations are increasingly committed to achieving and demonstrating good occupational health and safety performance. Methods: The aim of this study was to characterize the psychosocial risks in a cryopreservation laboratory and to develop a predictive model for psychosocial risk management. The methodology followed to collect the information was the inquiry by questionnaire that was applied to a sample comprising 200 employees. Results: The results show that most of the respondents are aware of the psychosocial risks, identifying interpersonal relationships and emotional feelings as the main factors that lead to this type of risks. Furthermore, terms such as lack of resources, working hours, lab equipment, stress, and precariousness show strong correlation with psychosocial risks. The model presented in this study, based on artificial neural networks, exhibited good performance in the prediction of the psychosocial risks. Conclusion: This work presents the development of an intelligent system that allows identifying the weaknesses of the organization and contributing to the enhancement of the psychosocial risks management.