• Title/Summary/Keyword: Safety case

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Prediction of Radionuclide Inventory for Low- and Intermediate-Level Radioactive Waste by Considering Concentration Limit of Waste Package (처분방사능량제한치를 고려한 중저준위 방사성폐기물 처분시설의 핵종재고량 산정(안))

  • Jung, Kang Il;Kim, Min Seong;Jeong, Noh Gyeom;Park, Jin Beak
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.15 no.1
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    • pp.65-82
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    • 2017
  • The result of a preliminary safety assessment that was completed by applying the radionuclide inventory calculated on the basis of available data from radioactive waste generation agencies suggested that many difficulties are to be expected with regard to disposal safety and operation. Based on the results of the preliminary safety assessment of the entire disposal system, in this paper, a unit package exceeding the safety goal is selected that occupies a large proportion of radionuclides in intermediate-level radioactive waste. We introduce restrictions on the amount of radioactivity in a way that excludes the high surface dose rate of the package. The radioactivity limit for disposal will be used as the baseline data for establishing the acceptance criteria and the disposal criteria for each disposal facility to meet the safety standards. It is necessary to draw up a comprehensive safety development plan for the Gyeongju waste disposal facility that will contribute to the construction of a Safety Case for the safety optimization of radioactive waste disposal facilities.

Application and Analysis of the Paradigm of Software Safety Assurance for a Digital Reactor Protection System in Nuclear Power Plants (원전 디지털 원자로보호계통 소프트웨어 안전보증 패러다임 적용 및 분석)

  • Kwon, Kee-Choon;Lee, Jang-Soo;Jee, Eunkyoung
    • KIISE Transactions on Computing Practices
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    • v.23 no.6
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    • pp.335-342
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    • 2017
  • In the verification and validation procedures regarding the safety-critical software of nuclear power plants for the attainment of the requisite license from the regulatory body, it is difficult to judge the safety and dependability of the development, implementation, and validation activities through a simple reading and review of the documentation. Therefore, these activities, especially safety assurance activities, require systematic evaluation techniques to determine that software faults are acceptable level. In this study, a safety case methodology is applied in an assessment of the level and depth of the results of the development and validation of a manufacturer in its targeting of the bistable processor of a digital reactor protection system, and the evaluation results are analyzed. This study confirms the possibility of an effective supplementation of the existing safety demonstration method through the application of the employed safety case methodology.

A Study on Risk Frequency Estimation of Runway End Safety Area (활주로종단안전구역의 위험빈도 추정 연구)

  • Kim, Do-Hyeon;Sheen, Dong-Jin
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.18 no.3
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    • pp.34-41
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    • 2010
  • 'Aviation Safety' is the state in which the risk of harm to persons or of property damage is reduced to, and maintained at or below, an acceptable level through a continuing process of hazard identification and risk management in the aviation field. 'Risk' is the assessed potential for adverse consequences resulting from a hazard and 'Risk assessment' involves consideration of both the frequency and the severity of any adverse consequence. This study focused on the risk frequency about a case airport which does not meet the 'Runway end safety area' requirement of ICAO SARPs and Korea standards and used 'RSA risk model' for estimating the risk frequency. As results of this study, risk frequency of the runway end safety areas in the case airport is higher than that of 'Runway end safety area' requirement of ICAO SARPs and Korea standards, which means that alternatives for risk frequency mitigation to a level as low as reasonably practicable is required in the case airport. The optimum solution analysed from this study is to impose restriction of aircraft operation when the runway condition is poor(icing condition) and also it snows in the case airport.

A Study on the Analysis of Simulation for Improvement Evacuation Safety Assessment of Building in Fire (건축물의 화재 시 피난안전성 평가 개선을 위한 시뮬레이션 분석 연구)

  • Kim, Hye-won;Kim, Yoon-Seong;Lee, Byeong-Heun;Jin, Seung-Hyeon;Koo, In-Hyuk;Kwon, Young-Jin
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.11a
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    • pp.107-108
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    • 2020
  • There is a need to analyze various factors in evacuation safety assessment of building in fire. In the current performance based design, evacuation safety assessment in case of fire is being conducted through the simulation as FDS and Pathfinder. However, the location and size of the door, the location of evacuation in the event of a fire are not considered when design. Accordingly, it is difficult to determine the worst case scenario considering the actual fire. Therefore in this study, in this study, we will propose an appropriate evaluation plan through simulation considering the worst-case scenario that may occur in case of fire.

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Progressively gangrenous limbs in Korean indigenous calves

  • Kim Bum-Seok;Camer Gerry Amor;Berzina Dace;Chekarova Irina;Zeeshan Muhammad;Borisova Irina;Blank Ivar;Ejaz Sohail;Park Hee-Jin;Kwon Jung-Kee;Lim Chae-Woong
    • Korean Journal of Veterinary Service
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    • v.29 no.4
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    • pp.493-496
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    • 2006
  • This study investigated cases of progressively necrotizing limbs in Korean indigenous calves. The recent case (Case 1) involved a 3-month old, male calf in Jeonbuk province that presented a visibly dry form of gangrene affecting joints of the forelimbs and the hind limbs. Radiograph revealed osteoarthritis possibly resulting from pressure of disrupted joint skin, fasciae, deeper underlying musculatures and tendon. Histopathology of affected tissue showed necrotizing; severely thrombosed dilated blood vessels with rechanneling microvasculatures. The lack of substantial infectious inflammatory exudates in the vital organs and the inability to respond to antimicrobial treatment bolstered the notion that the observed thromboembolic and vascular lesion was attributed to possible vasoconstrictive effects of ergot alkaloids. Case 2: A previously encountered similar case in a 4-month old, male calf showing gangrene of hind limbs and posterior ataxia was likewise presented. These two cases were impressed as probable ergotism. Ergotism may be uncommon or underreported in Korea. Future isolation of ergot alkaloids in feeds or in pasture is highly suggested.

Carbon monoxide poisoning-induced encephalopathy in a carbon dioxide arc welder: a case report

  • Seongwon Ma;Hoekyeong Seo;Dong Joon Park;Byeongju Choi;Shinhee Ye
    • Annals of Occupational and Environmental Medicine
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    • v.34
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    • pp.19.1-19.9
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    • 2022
  • Background: It is widely known that carbon dioxide (CO2) arc welding generates carbon monoxide (CO). However, to the best of our knowledge, no case reports have been published regarding CO poisoning in CO2 arc welders. Therefore, we aimed to report a case of CO poisoning-induced encephalopathy in a CO2 arc welder in the Republic of Korea to inform about the dangers of CO exposure among CO2arc welders. Case presentation: A 40-year-old man working as a CO2 arc welder for 15 years visited a local hospital with a tremor, involuntary urination, and speaking gibberish, on April 9, 2019. He stated that he had intermittent headache and forgetting symptoms for the last 5 years, and had been lost on the way to work several times. On April 9, 2019, he was diagnosed with CO poisoning-induced encephalopathy through brain magnetic resonance imaging. He received hyperbaric oxygen therapy, and some of his symptoms improved. According to the exposure assessment of his work environment, he was continuously exposed to high concentrations of CO for 15 years while operating CO2 arc welding machines. Conclusions: After evaluating the patient's work environment and evaluating his medical history, we concluded that his encephalopathy was caused by CO exposure during CO2 arc welding. Thus CO2 arc welders must be aware of the risk of CO poisoning and strive to avoid CO exposure.

An Improved Method of Developing Safety-Related Application Conditions for Safety Design of Railway Signalling Systems (철도신호시스템의 안전 설계를 위한 개선된 안전성 적용 조건 도출 방법)

  • Baek, Young-Goo;Lee, Jae-Chon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.11
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    • pp.31-45
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    • 2017
  • According to the railway accident statistics in recent years, the frequency of accidents has been significantly reduced, due to the advance of related technologies and the establishment of safety information management systems. Nonetheless, accidents due to errors in the operation and maintenance phase and faults in safety design continue to occur. Therefore, to prevent accidents, guidelines for the safety design and manufacture of railway vehicles were established, and a request for the independent safety evaluation of safety designs was made. To respond to this, rail system developers must prepare safety cases as a safety activity product. One of the main items of these safety cases is the safety-related application conditions (SRAC) and, thus, the question of how to develop these SRAC is an important one. The SRAC studies reported so far focused only on the simplicity of the derivation procedure and the specific safety activities in the design phase. This method seems to have the advantage of quickly deriving SRAC items. However, there is a risk that some important safety-related items may be missing. As such, this paper proposes an improved method of developing the SRAC based on the idea of performing both the safety design and safety evaluation activities throughout the whole system lifecycle. In this way, it is possible to develop and manage the SRAC more systematically. Especially, considering the SRAC from the initial stage of the design can allow the safety requirements to be reflected to a greater extent. Also, an application case study on railway signaling systems shows that the method presented herein can prevent the omission of important safety-related items, due to the consideration of the SRAC throughout the system lifecycle.