• Title/Summary/Keyword: Severe accidents

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PREDICTION OF SEVERE ACCIDENT OCCURRENCE TIME USING SUPPORT VECTOR MACHINES

  • KIM, SEUNG GEUN;NO, YOUNG GYU;SEONG, POONG HYUN
    • Nuclear Engineering and Technology
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    • v.47 no.1
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    • pp.74-84
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    • 2015
  • If a transient occurs in a nuclear power plant (NPP), operators will try to protect the NPP by estimating the kind of abnormality and mitigating it based on recommended procedures. Similarly, operators take actions based on severe accident management guidelines when there is the possibility of a severe accident occurrence in an NPP. In any such situation, information about the occurrence time of severe accident-related events can be very important to operators to set up severe accident management strategies. Therefore, support systems that can quickly provide this kind of information will be very useful when operators try to manage severe accidents. In this research, the occurrence times of several events that could happen during a severe accident were predicted using support vector machines with short time variations of plant status variables inputs. For the preliminary step, the break location and size of a loss of coolant accident (LOCA) were identified. Training and testing data sets were obtained using the MAAP5 code. The results show that the proposed algorithm can correctly classify the break location of the LOCA and can estimate the break size of the LOCA very accurately. In addition, the occurrence times of severe accident major events were predicted under various severe accident paths, with reasonable error. With these results, it is expected that it will be possible to apply the proposed algorithm to real NPPs because the algorithm uses only the early phase data after the reactor SCRAM, which can be obtained accurately for accident simulations.

The Relationship between Psychiatric Consequences and Injury Severity Following Traffic Accidents (교통사고후 외상심각도와 정신과적 증상의 관계)

  • Lee, Moon-In;Park, Sang-Hag;Kim, Sang-Hoon;Kim, Jae-Min;Kim, Hack-Ryul
    • Korean Journal of Psychosomatic Medicine
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    • v.12 no.1
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    • pp.66-75
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    • 2004
  • Objectives: This study was intended to see the relationship between psychiatric consequences and injury severity following traffic accidents. Methods: We surveyed the 134 patients who were hospitalized from 1994 to 2003 at Chosun University Hospital for psychiatic disability evaluation following traffic accident. We reevaluate demographic factors from admission note. Psychiatric symptoms from mental status exam in medical records. Psychological tests(MMPI, BAI, BDI, K-WAIS) were done. Then we calculate the injury severity score and McBride's rate of disability due to diagnosis from emergency care hospital records. Their relationships were evaluated by statistical methods which were t-test and Pearson correlation analysis using SPSS-10. Results: When physical injury was not severe, suicidal attempt was more frequent and depression, hysteria, psychasthenia, psychopathic deviation subscales were high in MMPI. But when physical injury was severe, they have diffficulty in concentration, impaired orientation, and changed in IQ score. There was no relationship between physical injury severity and faking bad scales(F, Ds-r). Conclusion: We must not assume when physical injury was not severe, the severe sympomts are just faking for their benefit.

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Comparative analysis of Traffic Accidents Characteristics using Various Types of Industrial Complexes (산업단지 유형에 따른 교통사고 특성 비교 분석)

  • Lee, Yuhwa;Jung, Byoung-Cheol
    • International Journal of Highway Engineering
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    • v.19 no.6
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    • pp.201-212
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    • 2017
  • PURPOSES : The objective of this study is to identify the characteristics affecting traffic accidents that have occurred in 564 industrial complexes nationwide from 2011 to 2015. METHODS : The traffic accidents were specified using various factors such as industrial complex type (national VS. general), industrial complex degradation (old VS. non-old), location of complex (capital VS. non-capital), and traffic law violation (speeding, signal violation, and median invasion). The average number of crashes and accident ratio (fatal, severe, and both) in terms of characteristics of industrial complexes were calculated. With a sample of crashes of the industrial complexes for 5 years, statistical significances were tested to analyze and compare the differences based on industrial complex and traffic law characteristics using parametric and non-parametric methods. RESULTS : From statistical results, it is observed that the crash frequency occurring in old industrial complexes is three times higher than that in non-old industrial complexes. Old industrial complexes located in a capital area, old national industrial complexes, and old general industrial complexes are considerably related to higher crash frequency, but the fatal accident ratio appeared to have no statistical difference across industrial complex characteristics. Severe crashes are more likely to occur in non-old industrial complexes on an average. CONCLUSIONS : It is necessary to eliminate potential threats to roads and traffic in the same manner as illegal parking in industrial complexes through the restoration of old industrial complexes. To improve the efficiency of road infrastructure, efforts should be made to improve traffic safety in accordance with industrial characteristics such as planning and operation of relevant local government programs.

Characteristics and Outcomes of Patients with Bicycle-Related Injuries at a Regional Trauma Center in Korea

  • Lee, Yoonhyun;Lee, Min Ho;Lee, Dae Sang;Kim, Maru;Jo, Dae Hyun;Park, Hyosun;Cho, Hangjoo
    • Journal of Trauma and Injury
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    • v.34 no.3
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    • pp.147-154
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    • 2021
  • Purpose: We analyzed the characteristics and outcomes of patients with bicycle-related injuries at a regional trauma center in northern Gyeonggi Province as a first step toward the development of improved prevention measures and treatments. Methods: The records of 239 patients who were injured in different types of bicycle-related accidents and transported to a single regional trauma center between January 2017 and December 2018 were examined. This retrospective single-center study used data from the Korea Trauma Database. Results: In total, 239 patients experienced bicycle-related accidents, most of whom were males (204, 85.4%), and 46.9% of the accidents were on roads for automobiles. Forty patients (16.7%) had an Injury Severity Score (ISS) of 16 or more. There were 125 patients (52.3%) with head/neck/face injuries, 97 patients (40.6%) with injuries to the extremities, 59 patients (24.7%) with chest injuries, and 21 patients (8.8%) with abdominal injuries. Patients who had head/neck/face injuries and an Abbreviated Injury Score (AIS) ≥3 were more likely to experience severe trauma (ISS ≥16). In addition, only 13 of 125 patients (10.4%) with head/neck/face injuries were wearing helmets, and patients with injuries in this region who were not wearing helmets had a 3.9-fold increased odds ratio of severe injury (AIS ≥2). Conclusions: We suggest that comprehensive accident prevention measures, including safety training and expansion of safety facilities, should be implemented at the governmental level, and that helmet wearing should be more strictly enforced to prevent injuries to the head, neck, and face.

The Relationship between Hospital Selection by Employer and Disabilities in Occupational Accidents in Korea

  • Ahn, Joonho;Jang, Min;Yoo, Hyoungseob;Kim, Hyoung-Ryoul
    • Safety and Health at Work
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    • v.13 no.3
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    • pp.279-285
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    • 2022
  • Background; In the event of an industrial accident, the appropriate choice of hospital is important for worker health and prognosis. This study investigates whether the choice of hospital by the employer in the case of industrial accidents affects the prognosis of injured employees. Methods; Data from the 2018 Panel Study of Workers' Compensation Insurance in Korea were used in an unmatched case-controlled study. The exposure variable is "hospital selection by an employer," and the outcome variable is 'worker's disability." Odds ratios (ORs) were estimated by modified Poisson regression and adjusted for age, gender, underlying disease, injury severity, and workplace size and stratified by industrial classification. The group at increased risk was analyzed and stratified by age, gender, and area. Results; In the construction industry, hospital selection by the employer was significantly associated with increased risk of disability (adjusted OR 1.26; 95% confidence interval [CI]; 1.20-1.32) and severe disability (adjusted OR 1.38; 95% CI; 1.08-1.76) among the injured. Female and younger workers not living in the Seoul capital area were more at risk of disability and severe disability than those living in the Seoul capital area. Conclusions; Hospital selection by employers affects the prognosis of workers injured in an industrial accident. For protecting workers' health and safety, workplace emergency medical systems should be improved, and the selection of appropriate hospitals to supply treatment should be reviewed.

A Study on Improvement Plans for Safety and Health Technical Support Project on Small Business by Field (소규모 사업장 안전보건 기술지원사업의 분야별개선방안에 대한 연구)

  • Yongro Ahn;Taekeun Oh
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.3
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    • pp.625-632
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    • 2023
  • Due to the recent occupational accidents, the government made efforts such the Severe Accident Punishment Act and roadmap for reducing severe accidents. In particular, more than 80% accidents occur in small businesses, such as those with less than 50 employees and construction sites with a construction cost of less than 100 million, and practical efforts are needed to reduce them. In small businesses, the appointment of a safety managers and safety and health management regulations have been excluded in whole or in part, and technical guidance from an institution specializing in accident prevention is compulsory to supplement them. In this study, the problems of the safety and health technology support project for small workplaces has been identified through a survey and improvement plans were proposed.

Risk assessment of gillnet fishing vessels in South Korea: a statistical analysis of occupational accidents 2016-2020

  • Yoo-Won Lee;Kyung-Jin Ryu;Su-Hyung Kim;Hyungju Kim;Kwi Yeon Koo;Chaegil Lee;Seonghun Kim
    • Fisheries and Aquatic Sciences
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    • v.27 no.1
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    • pp.7-16
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    • 2024
  • Fishing is considered one of the most dangerous industries alongside mining that needs further efforts to improve safety. In this study, we have investigated safety management of the gillnet fishing industry in South Korea through identifying safety level and classifying common accident types from the statements of accident com-pensation insurance payments for the last 5 years (2016-2020). There were in total 3,895 accidents and 159 fatalities with an average accident frequency of 5.34 × 10-2 per year per fisher and an average fatality of 2.18 × 10-3 fishers per year. We have also identified that 62.4% of the accidents occurred during Fishing (FS), and the most common and the most severe accident type is Slips and Trips (ST) and Other (OT) marine accidents such as collision and capsizing, respectively. The hand was most frequently injured. Finally, the risk assessment indicated that most of the accident types of gillnet fishing in South Korea have unacceptable levels of risks, and it is urgent to implement improved safety measures to reduce accidents during gillnet fishing operation. The findings of this study are expected to provide valuable data to create a safer working environment for fishers working on gillnet fishing vessels.

Psychosocial Outcome after Head Injury (두부외상후 심리사회적 예후)

  • Park, Ki-Chang;Kim, Hun-Joo
    • Journal of Korean Neurosurgical Society
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    • v.29 no.2
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    • pp.196-202
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    • 2000
  • Objective : This study was designed to evaluate the relationship between the initial neurosurgical or psychosocial factors and the psychosocial outcome. Patients and Methods : We analyzed 123 head-injured patients who were referred to the department of psychiatry for the evaluation of psychosocial function. We analyzed initial neurosurgical variables such as Glasgow Coma scale(GCS) score, skull fracture, CT finding, and psychosocial outcomes with regards to psychosis, personality change, depression, anxiety and IQ on Intelligence Scale. Results : Patients with mild head injury(GCS score 13-15, N=94, 76.4%) had better recovery rate on Glasgow Outcome Scale(GOS), less personality change than those with moderate or severe head injury. However, depression, anxiety and intelligence were not significantly different between two groups. The skull fracture(N=37, 30.1%) did not influence on the psychosocial outcome with reference to personality change, depression, anxiety and intelligence. The patients with abnormal CT findings(N=64, 52%) had lower recovery rate on GOS, more frequent tendency in psychosis, personality change and severe depression, less frequent in anxiety and mild depression, than patients with normal CT finding. However, levels of intelligence were not different between two groups. The patients with industrial accidents(IA) had lower educational level, milder head injury, more delay for the psychiatric evaluation (longer treatment period) than those with motor vehicular accidents(MVA). The psychosocial outcome with reference to personality change, depression, anxiety, intelligence were not different between two groups. Conclusion : These findings indicate that the more severe initial trauma, the poorer psychosocial outcome. However, it was frequently observed that patients with mild head injury suffered from mild anxiety and depression. Therefore mild head injury appeared to be more complicated by psychosocial stressors. The patients with IA, despite the fact that initial head injury was mild, required longer treatment period than MVA.

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Characteristics of Radioactive Aerosol Particles in Nuclear Power Plant Containments (원자로건물 내부 방사성 에어로졸 입자의 특성)

  • Kim, Min Young;Park, Sung Hoon
    • Particle and aerosol research
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    • v.10 no.4
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    • pp.137-154
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    • 2014
  • Prediction of the behavior of radioactive aerosol particles in a containment is of importance for the assessment of the consequences of nuclear power plant severe accidents because most radioactive air pollutants are emitted as aerosol particles upon severe accident. The performance of engineering safety features (ESFs) is also influenced by the characteristics of the aerosol particles. In this article, the characteristics of aerosol particles in reactor containments reported by previous studies were reviewed. The results of the experiments for postulated accidents in test reactors, for aerosol behavior analysis using artificial test aerosols, and for ESF performance evaluation were summarized. The summary of this article will be of use in designing and performance-evaluating ESFs.

Improving Accident Tolerance of Nuclear Fuel with Coated Mo-alloy Cladding

  • Cheng, Bo;Kim, Young-Jin;Chou, Peter
    • Nuclear Engineering and Technology
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    • v.48 no.1
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    • pp.16-25
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    • 2016
  • In severe loss of coolant accidents (LOCA), similar to those experienced at Fukushima Daiichi and Three Mile Island Unit 1, the zirconiumalloy fuel claddingmaterials are rapidlyheateddue to nuclear decay heating and rapid exothermic oxidation of zirconium with steam. This heating causes the cladding to rapidly react with steam, lose strength, burst or collapse, and generate large quantities of hydrogen gas. Although maintaining core cooling remains the highest priority in accident management, an accident tolerant fuel (ATF) design may extend coping and recovery time for operators to restore emergency power, and cooling, and achieve safe shutdown. An ATF is required to possess high resistance to steam oxidation to reduce hydrogen generation and sufficient mechanical strength to maintain fuel rod integrity and core coolability. The initiative undertaken by Electric Power Research Institute (EPRI) is to demonstrate the feasibility of developing an ATF cladding with capability to maintain its integrity in $1,200-1,500^{\circ}C$ steam for at least 24 hours. This ATF cladding utilizes thin-walled Mo-alloys coated with oxidation-resistant surface layers. The basic design consists of a thin-walled Mo alloy structural tube with a metallurgically bonded, oxidation-resistant outer layer. Two options are being investigated: a commercially available iron, chromium, and aluminum alloy with excellent high temperature oxidation resistance, and a Zr alloy with demonstratedcorrosionresistance.Asthese composite claddings will incorporate either no Zr, or thin Zr outer layers, hydrogen generation under severe LOCA conditions will be greatly reduced. Key technical challenges and uncertainties specific to Moalloy fuel cladding include: economic core design, industrial scale fabricability, radiation embrittlement, and corrosion and oxidation resistance during normal operation, transients, and severe accidents. Progress in each aspect has been made and key results are discussed in this document. In addition to assisting plants in meeting Light Water Reactor (LWR) challenges, accident-tolerant Mo-based cladding technologies are expected to be applicable for use in high-temperature helium and molten salt reactor designs, as well as nonnuclear high temperature applications.