• Safety and Health at Work
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• v.10 no.1
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• pp.54-60
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• 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 Journal of Internal Korean Medicine
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• v.40 no.3
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• pp.551-556
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• 2019

Objectives: This study aimed to introduce a clinical case of asymptomatic microhematuria due to suspicion of kidney trauma following a motor vehicle accident. Methods: A 19-year-old male was hospitalized with the chief complaint of back pain after a motor vehicle accident. He showed an elevated urine red blood cell (RBC) level in the laboratory test, although no specific traumatic lesions were present on the body. He was assessed to have asymptomatic microhematuria, and Zhu Ling Tang (polyporus decoction) was given to him to be taken three times daily. Results: After the treatment, the level of urine red blood cells returned to normal range. Adverse events were not observed. Conclusions: Zhu Ling Tang caused a short-term improvement in the urinalysis levels of a patient with asymptomatic hematuria. However, further studies are needed, as this study is only a single-case report.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4560-4570
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• 2022

Dynamic fault tree (DFT) and its related research methods have received extensive attention in safety analysis and reliability engineering. DFT can perform reliability modelling for systems with sequential correlation, resource sharing, and cold and hot spare parts. A technical modelling method of DFT is proposed for modelling ship collision accidents and loss-of-coolant accidents (LOCAs). Qualitative and quantitative analyses of DFT were carried out using the cutting sequence (CS)/extended cutting sequence (ECS) method. The results show nine types of dynamic fault failure modes in ship collision accidents, describing the fault propagation process of a dynamic system and reflect the dynamic changes of the entire accident system. The probability of a ship collision accident is 2.378 × 10^-9 by using CS. This failure mode cannot be expressed by a combination of basic events within the same event frame after an LOCA occurs in a marine nuclear reactor because the system contains warm spare parts. Therefore, the probability of losing reactor control was calculated as 8.125 × 10^-6 using the ECS. Compared with CS, ECS is more efficient considering expression and processing capabilities, and has a significant advantage considering cost.

• Anxiety and mood
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• v.12 no.1
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• pp.21-27
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• 2016

Objective : The aim of this study was to investigate the relationship between subjective sleep problems and various types of traumatic events of patients with depressive disorder. Methods : A total of 411 patients diagnosed with depressive disorders were recruited in this study. The participants filled out Life Time Events Checklist (LEC), Pittsburgh Sleep Quality Index (PSQI), Beck Depression Inventory (BDI), and State-Trait Anxiety Inventory (STAI). We used the independent t-test and analysis of covariance to compare each component of PSQI between depressive patients with and without traumatic experiences. Results : The groups of patients who experienced a serious accident at work, home or during recreational activity, sexual assault, other unwanted or uncomfortable sexual experience, life-threatening illness or injury, and sudden, unexpected death of a near and dear one showed lower scores in a few components of PSQI. Sleep disturbance was a common problem in all five groups. Lower subjective sleep quality and longer sleep latency was observed in three groups. There were no differences in the other components of PSQI among groups. Conclusion : This study showed that various types of traumatic events may have different effects on subjective sleep quality as a consequence of the traumatic event which they had experienced.

• Journal of the Korean Society of Safety
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• v.34 no.3
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• pp.102-110
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• 2019

This paper describes the work and results of the preliminary Probabilistic Safety Assessment (PSA) for a research reactor in the design phase. This preliminary PSA was undertaken to assess the level of safety for the design of a research reactor and to evaluate whether it is probabilistically safe to operate and reliable to use. The scope of the PSA described here is a Level 1 PSA which addresses the risks associated with core damage. After reviewing the documents and its conceptual design, eight typical initiating events are selected regarding internal events during the normal operation of the reactor. Simple fault tree models for the PSA are developed instead of the detailed model at this conceptual design stage. A total of 32 core damage accident sequences for an internal event analysis were identified and quantified using the AIMS-PSA. LOCA-I has a dominant contribution to the total CDF by a single initiating event. The CDF from the internal events of a research reactor is estimated to be 7.38E-07/year. The CDF for the representative initiating events is less than 1.0E-6/year even though conservative assumptions are used in reliability data. The conceptual design of the research reactor is designed to be sufficiently safe from the viewpoint of safety.

• Nuclear Engineering and Technology
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• v.43 no.1
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• pp.63-74
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• 2011

The 600 MWe, pool-type, sodium-cooled, metallic fuel loaded KALIMER-600 (Korea Advanced LiquId MEtal Reactor, 600 MWe) has been conceptually designed with an emphasis on safety by self-regulating (inherent/intrinsic) negative reactivity feedback in the core. Its inherent safety under the ATWS (Anticipated Transient Without Scram) events was demonstrated in an earlier study. Initiating events of an HCDA (Hypothetical Core Disruptive Accident), however, also need to be analyzed for assessment of the margins in the current design. In this study, a hypothetical triple-fault accident, ULOF (Unprotected Loss Of Flow) with a reduced pump halving time, is investigated as an initiator of a core disruptive accident. A ULOF with insufficient primary pump inertia may cause core sodium boiling due to a power-to-flow mismatch. If the positive sodium reactivity resulting from this boiling is not compensated for by other intrinsic negative reactivity feedbacks, the resulting core power burst would challenge the fuel integrity. The present study focuses on determination of the limit of the pump inertia for assuring inherent reactivity feedback and behavior of the core after sodium boiling as well. Transient analyses are performed with the safety analysis code SSC-K, which now incorporates a new sodium boiling model. The results show that a halving time of more than 6.0 s does not allow sodium boiling even with very conservative assumptions. Boiling takes place for a halving time of 1.8 s, and its behavior can be predicted reasonably by the SSC-K.

• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.710-720
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• 2017

In Korea, many nuclear power plants operate at a single site based on geographical characteristics, but the population density near the sites is higher than that in other countries. Thus, multiunit accidents are a more important consideration than in other countries and should be addressed appropriately. Currently, there are many issues related to a multiunit probabilistic safety assessment (PSA). One of them is the quantification of a multiunit PSA model. A traditional PSA uses a Boolean manipulation of the fault tree in terms of the minimal cut set. However, such methods have some limitations when rare event approximations cannot be used effectively or a very small truncation limit should be applied to identify accident sequence combinations for a multiunit site. In particular, it is well known that seismic risk in terms of core damage frequency can be overestimated because there are many events that have a high failure probability. In this study, we propose a quantification method based on a Monte Carlo approach for a multiunit PSA model. This method can consider all possible accident sequence combinations in a multiunit site and calculate a more exact value for events that have a high failure probability. An example model for six identical units at a site was also developed and quantified to confirm the applicability of the proposed method.

• The Journal of Korean Obstetrics and Gynecology
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• v.32 no.4
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• pp.39-54
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• 2019

Objectives: The purpose of this study is to analyze both treatment and adverse events of Korean medicine treatment for whiplash associated disorder patients during pregnancy. Methods: We investigated the medical records of 44 pregnant patients who had got into car accidents from April 1, 2018 to May 31, 2019. Results: 100 percent of the inpatients and 88 precent of the outpatients were treated by acupuncture. 79 percent of the inpatients and 72 precent of the outpatients were treated by chuna, and 86 percent of the inpatients and 64 precent of the outpatients were treated by pharmacopuncture. Out of 32 patients with low back pain, 94 percent were treated by acupuncture, 47 percent by phramacopuncture and 38 precent by chuna. 90 percent of 31 patients with cervical pain were treated by acupuncture, 71 percent were treated by pharmacopuncture and 77 percent were treated by chuna. There were adverse events like cough, rhinorrhea, dilatation of cervix and worsen low back pain during or after the treatment. Conclusions: Korean medicine treatment including chuna and pharmacopuncture can be applied to pregnant women injured by traffic accident.

• Journal of the Ergonomics Society of Korea
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• v.36 no.3
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• pp.231-244
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• 2017

Objective: This study aims to understand the occupational injury characteristics of the workers in the motor vehicle parts (automobile parts) manufacturing industry and to present basic guidelines on accident prevention through accident analysis. Background: There occur many occupational injuries in the motor vehicle parts manufacturing industry. But there were few researches for the occupational injuries of the workers in the motor vehicle parts manufacturing industry. Method: This study analyzed the data of occupational injuries of 1,609 workers in the motor vehicle parts manufacturing industry in 2015. The accident characteristics were analyzed by dividing them into worker related factors and accident related factors. Results: Among the occupational injuries of the workers in the motor vehicle parts manufacturing industry, 80.6% of the victims were males, 64.0% were older than 40. 57.8% of the victims were employed by the companies with less than 50 workers. In addition, there was a difference in accident characteristics according to age, work experience, employment type, events or exposures, accident time of the day, agents, natures of injuries and illnesses, injured organs and injured body part. Conclusion: It is important to prevent equipment/machinery accidents. For this purpose, more efforts should be made to establish safety measures faithful to the basics of safety devices and safety work procedures. It is also suggested that prevention of disasters should be intensively carried out for workplaces with less than 50 employees and middle-aged and elderly people. Application: The result can be used to present guidelines for preventative measures for the workers in the motor vehicle parts manufacturing industry including safety education/training.

• Nuclear Engineering and Technology
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• v.47 no.1
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• pp.26-32
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• 2015

During the course of a severe accident in a light water nuclear reactor, large amounts of hydrogen can be generated and released into the containment during reactor core degradation. Additional burnable gases [hydrogen ($H_2$) and carbon monoxide (CO)] may be released into the containment in the corium/concrete interaction. This could subsequently raise a combustion hazard. As the Fukushima accidents revealed, hydrogen combustion can cause high pressure spikes that could challenge the reactor buildings and lead to failure of the surrounding buildings. To prevent the gas explosion hazard, most mitigation strategies adopted by European countries are based on the implementation of passive autocatalytic recombiners (PARs). Studies of representative accident sequences indicate that, despite the installation of PARs, it is difficult to prevent at all times and locations, the formation of a combustible mixture that potentially leads to local flame acceleration. Complementary research and development (R&D) projects were recently launched to understand better the phenomena associated with the combustion hazard and to address the issues highlighted after the Fukushima Daiichi events such as explosion hazard in the venting system and the potential flammable mixture migration into spaces beyond the primary containment. The expected results will be used to improve the modeling tools and methodology for hydrogen risk assessment and severe accident management guidelines. The present paper aims to present the methodology adopted by Institut de Radioprotection et de $S{\hat{u}}ret{\acute{e}}$ $Nucl{\acute{e}}aire$ to assess hydrogen risk in nuclear power plants, in particular French nuclear power plants, the open issues, and the ongoing R&D programs related to hydrogen distribution, mitigation, and combustion.