• Nuclear Engineering and Technology
• /
• v.55 no.3
• /
• pp.999-1008
• /
• 2023

Deformed fuel rods can cause a partial blockage of the flow area in a subchannel. Such flow blockage will influence the core coolant flow and further the core heat transfer during the reflooding phase and subsequent severe accidents. Nevertheless, most of the system analysis codes simulate the accident process based on the assumed flow blockage ratio, resulting in inconsistencies between simulated results and actual conditions. This paper aims to study the influence of flow blockage in severe accident scenario of the CAP1400 reactor. First, the flow blockage model of ISAA code is improved based on the FRTMB module. Then, the ISAA-FRTMB coupling system is adopted to model and calculate the QUENCH-LOCA-0 experiment. The correctness and validity of the flow blockage model are verified by comparing the peak cladding temperature. Finally, the DVI Line-SBLOCA accident is induced to analyze the influence of flow blockage on subsequent CAP1400 reactor core heat transfer and core degradation. From the results of the DVI Line-SBLOCA accident analysis, it can be concluded that the blockage ratio is in the range of 40%-60%, and the position of severe blockage is the same as that of cladding rupture. The blockage reduces the circulation area of the core coolant, which in turn impacts the heat exchange between the core and the coolant, leading to the early failure and collapse of some core assemblies and accelerating the core degradation process.

• Child Health Nursing Research
• /
• v.25 no.4
• /
• pp.388-397
• /
• 2019

Purpose: This study aimed to identify the degree of accident prevention behavior, self-esteem, self-regulation ability, and social support among middle-school students, and investigate factors influencing their practice of accident prevention behaviors. Methods: The participants were 174 students from two middle schools located in J city. Data were collected from December 28, 2017 to February 9, 2018 using self-reported questionnaires. Results: The mean score were $3.08{\pm}0.37$ of 4 for practice of accident prevention behaviors, $3.07{\pm}0.57$ of 4 for self-esteem, $3.69{\pm}0.48$ of 5 for self-regulation ability, and $3.38{\m}0.75$ of 5 for social support. Positive correlations were found among self-regulation ability, self-esteem, social support, and practice of accident prevention behaviors. The factors influencing the practice of accident prevention behaviors were personality (being 'haste') (${\beta}=-.20$, p=.003), self-regulation ability (${\beta}=.48$, p<.001), and social support (${\beta}=.23$, p<.001). These factors explained 39.0% of the variance in practice of accident prevention behaviors. Conclusion: It was found that the middle-school students engaged in prevention behavior to an extent that was insufficient to prevent accidents. Therefore, it is necessary to develop intervention strategies to improve the practice of accident prevention behavior among middle-school students, considering self-regulation ability, social support, and personality, which affect the practice of accident prevention behaviors.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2023.05a
• /
• pp.142-143
• /
• 2023

A contact accident with gantry cranes involving the container ship MV Milano Bridge in Busan New Port took place on 6 April 2020. The report concluded that the pilot unreasonably piloted the ship with impaired maneuverability and without a proper pilotage plan. Analyzing the entire system by CAST model gives a holistic approach in linking all the key components and their roles as well as violations that led to the accident, stepping away from placing the blame on only one component in the system. Furthermore, analyzing the accident as an system theory gives a clear overview of the relationships between system components and how these interactions led to the accident.

• Korean Journal of Health Education and Promotion
• /
• v.19 no.1
• /
• pp.1-15
• /
• 2002

In this study, it is aimed to clarify the status of safety accident and safety health education and risk factors on safety accidents among the selected high school students. The study is accomplished by the survey which includes a total of 558 students sampled from the six high school. The survey took for 10 days from the date of 3th July 2000 to 13th July 2000 and the results were as follows; 1. The rate of experience of safety health education during last one year was 26.4% and the rate of accident during last one month was 20.6%. 2. The risk factors of safety accident during last one year were understanding degree of safety health education(R.R.=2.81), experience of smoking(R.R.=2.55), educational level of mother (R.R=l.63) From the results of this study, we are to propose as follow; Because the purpose of safety health education is the practice, it is important to induce changing the recognition and behavior. Therefore the government have to build up experience place, to bring up professional teacher of safety health education. It need to develope a reference of each subject and to utilize various media. Especially it need to take of education comprehensive health and environmental inducing safety health subject.

• Nuclear Engineering and Technology
• /
• v.54 no.1
• /
• pp.138-151
• /
• 2022

Cladding ballooning and rupture are the important phenomena at the early stage of a severe accident. Most severe accident analysis codes determine the cladding rupture based on simple parameter models. In this paper, a FRTMB module was developed using the thermal-mechanical model to analyze the fuel mechanical behavior. The purpose is to judge the cladding rupture with the severe accident analysis code. The FRTMB module was integrated into the self-developed severe accident analysis code ISAA to simulate the PHEBUS FPT3 experiment. The predicted rupture time and temperature of the cladding were basically consistent with the measured values, which verified the correctness and effectiveness of the FRTMB module. The results showed that the rising of gas pressure in the fuel rod and high temperature led to cladding ballooning. Consequently, the cladding hoop strain exceeded the strain limit, and the cladding burst. The developed FRTMB module can be applied not only to rod-type fuel, but also to plate-type fuel and other types of reactor fuel rods. Moreover, the FRTMB module can improve the channel blockage model of ISAA code and make contributions to analyzing the effect of clad ballooning on transient and subsequent parts of core degradation.

• Journal of Navigation and Port Research
• /
• v.46 no.5
• /
• pp.400-408
• /
• 2022

Maritime transportation is one of the most complicated and hazardous business fileds. Maritime accidents still occur despite several precautions since maritime is exposed to natural factors more than any other industries. In this harsh environment as a part of their job, marine pilots often embark/disembark to/ from vessels and confront life-endangering personal accidents. In the maritime field, several risk assessments are applied. However, all of them could not evaluate occupational accident risk for maritime pilot specifically. This paper performs specific risk analysis using the bow-tie method based on past accident records. This paper aims to qualify root causes and quantify root causes by importance level according to occurrence probability. As a result of analysis, occupational accident occurrence probability is found to be 14%, indicating that accident occurrence rate is significantly high. Hence, the probability of root causes triggering accidents and accident occurrence probability can be ascertained so that preventive measurements can be implemented. Besides theoretical achievement, this paper provides safety awareness to marine pilots, Marine Pilot Organizations, and ship crew who play a key role during marine pilots' transfer.

• Journal of the Korean Society of Safety
• /
• v.33 no.5
• /
• pp.28-34
• /
• 2018

Recently, various engineering approaches have been widely used in the accident investigation field to identify the cause of the accident and to predict damage by accident. Computational analysis is the most commonly used method of accident investigation technique. This technique is mainly used to identify the mechanism of the accident generation and to determine the cause when it is difficult to reproduce the situation at the time of the accident or when it is impossible to perform a reproduction experiment. In this study, The computational fluid dynamics analysis for nitrogen asphyxiation accident generated by defect of building structural between diffusion outlet and cooling tower was performed to determine the inflow path of the suffocation gas, death possibility by concentration of suffocation gas and predicted the time of death due to the accident using 3D modeling and FLACS program. We can quantify diffusion concentration of asphyxiation gas and predict mechanism of death occurrence by accident and evaluate the consequence Analysis through this study. In the future, This method can be widely used in the field of gas safety by improving the reliability and validity of the analysis.

• Nuclear Engineering and Technology
• /
• v.55 no.10
• /
• pp.3787-3800
• /
• 2023

Reactivity Initiated Accident (RIA) scenarios require special attention using advanced simulation techniques due to their complexity and importance for nuclear power plant (NPP) safety. While the conservative approach has traditionally been used for safety analysis, it may lead to unrealistic results which calls for the use of best estimate plus uncertainty (BEPU) approach, especially with the current advances in computational power which makes the BEPU analysis feasible. In this work an Uncontrolled Control Element Assembly (CEA) Withdrawal at Full Power accident scenario is analyzed using the BEPU approach by loosely coupling the thermal hydraulics best-estimate system code (RELAP5/SCDAPSIM/MOD3.4) to the statistical analysis software (DAKOTA) using a Python interface. Results from the BEPU analysis indicate that a realistic treatment of the accident scenario yields a larger safety margin and is therefore encouraged for accident analysis as it may enable more economic and flexible operation.

• Safety and Health at Work
• /
• v.10 no.1
• /
• pp.54-60
• /
• 2019

Background: Increasing the establishment of integrated management systems (IMSs) is done with the purpose of leaving traditional management methods and replacing them with modern management methods. Thus, the present study sought to analyze the events and investigate the impact of IMS on health and safety performance indices in an Iranian combined cycle power plants. Methods: This case study was conducted in 2012 in all units of the Yazd Combined Cycle Power Plant on accident victims before and after the implementation of IMS. For data analysis and prediction of indices after the implementation of IMS, descriptive statistics and Kolmogorov-Smirnov test, Chi-square, linear regression, and Cubic tests were conducted using SPSS software. Results: The number of people employed in the power plant in an 8-year period (2004-2011) was 1,189, and 287 cases of work-related accidents were recorded. The highest accident frequency rate and accident severity rate were in 2004 (32.65) and 2008 (209), respectively. Safe T-score reached to below -3 during 2010-2011. In addition, given the regression results, the relation between all predictor variables with outcomes was significant (p < 0.05), except for the variable $X^1$ belonging to the accident severity rate index. Conclusion: The implementation of safety programs especially that of IMS and its annual audits has had a significant impact on reducing accident indices and improving safety within the study period. Accordingly, health and safety management systems are appropriate tools for reducing accident rate, and the use of regression models and accident indices is also a suitable way for monitoring safety performance.

• The Korean Journal of Emergency Medical Services
• /
• v.9 no.2
• /
• pp.5-20
• /
• 2005

Purpose: This study is to examine the relationship between safety awareness and safety accident occurrence with elementary school students. Materials and methods: It selected 10 elementary schools under the supervision of Jeonnam Board of Education and sampled 700 students randomly from 2-3 classes in the 5th and the 6th grade. One preliminary survey was conducted to revise and complement the contents and forms of questionnaire with 70 students of a school from Apr. 1 to 6, 2004 and this study was conducted from Apr. 10 to 30, 2004. Total 700 questionnaires were distributed and 681 were collected (97%) and 602 were used for final analysis except 79 lacking responses. Data collected were analyzed with SPSS statistical program. Results: The average score of safety awareness of subjects by area was high as 2.72 points out of a possible 3. Area showing the highest safety awareness was safety from fire. Girl students had higher safety awareness than boy students. The fifth graders had higher safety awareness than the sixth graders. In safety awareness by the number of siblings, single son or single daughter showed the highest safety awareness. 53.2% of the subjects experienced accident for one year, the frequency of accident was mostly once and most of accidents were occurred at school. Accidents for the last year were higher in boy students, the sixth graders. According to relationship between safety awareness and safety accident, group with lower safety awareness in school safety(P < .022), traffic safety(P < .016), fire safety(P < .019), home safety(P < .007) and accident treatment and first aid(P < .003) had higher safety accidents than that with higher safety awareness. Conclusion: Development of safety education program by grade, that of parents safety education program, field experience and practice with students, teachers and parents and various safety education programs should be substantially and repeatedly accomplished for prevention education of safety accidents. In addition, to prevent and cope with safety accidents, safety education should be reflected on normal education, safety education textbook be developed, special safety education teachers be employed for safety education.