• Title/Summary/Keyword: Criticality analysis

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Design Study of A Spent Fuel Shipping Cask for Korea Nuclear Unit-1 (고리 1호기의 기사용 핵연료 집합체 수송용기 설계에 관한 연구)

  • Moo Han Kim;Chang Sun Kang
    • Nuclear Engineering and Technology
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    • v.14 no.4
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    • pp.196-203
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    • 1982
  • To transport the spent fuel assemblies of Korea Nuclear Unit 1, which is a Westinghouse type two loop pressurized water reactor, it has been found that steel is the most appropriate material for the design of a shipping cask in comparison with lead and depleted uranium. The proposed shipping cask will transport nine fuel assemblies at the same time and is well within the weight limit of transportation by unrestricted rail car. The cask requires 33cm thick steel shield and 27cm thick water region to satisfy the 3 feet apart dose rate limit set forth in 10 CFR 71, and 1.27cm thick steel boron fuel basket to hold the fuel elements inside the cask and control the effective multiplication factor. As a safety analysis, the fuel cladding and centerline temperatures were calculated under the accident condition of complete loss of water coolant, and it was found that the temperature was much lower than the limit of the melting point. k$_{eff}$ was calculated with fresh fuel assemblies, which was found to be well lower than 0.95. For shielding computation, the multipurpose Monte Carlo code MORSE-CG and one dimensional discrete ordinates transport code ANISN were used, and the Monte Carlo codes KENO and MORSE-CG were used for criticality calculation. The radiation source terms were calculated using ORIGEN-79.9.

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Atom Number Densities for Uranyl Nitrate Solution (질산우라늄용액의 구성원소별 원자수밀도)

  • Seung Gy Ro;Duck Kee Min;Jung-Kyoon Chon
    • Nuclear Engineering and Technology
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    • v.14 no.3
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    • pp.103-109
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    • 1982
  • An empirical formula for determining water content as functions of uranium concentration and nitric acid normalities in uranyl nitrate solutions has been derived from a least-squares analysis of experimental data, i.e., uranium concentration, nitric acid normalities and solution densities for a large number of UO$_2$(NO$_3$)$_2$ solutions. The formula derived is Q=1-0.3628C-0.0327H$^{+}$ where Q, C, and H$^{+}$ stand for water content (g/cc), uranium concentration (g/cc), ana nitric acid normality, respectively. Atom number densities and nuclear criticality for hypothetical uranyl nitrate solutions have been calculated by using the empirical formula, ana compared with the results obtained on the basis of uranium concentration, nitric acid normality, and solution density. The empirical formula derived in this study seems to be useful in uranium concentrations ranging from 0.295g/cc down to 0.004g/cc and nitric acid normality from 5.06 to 1.00..00.

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Research to define facility type, project consideration and restriction when conceiving civil-military sharing facilities, by applying the Delphi technique (델파이기법을 활용한 민군간 공용 시설유형 및 고려요소 판단 연구)

  • Gong, Keum Rok;Kang, Han-Seung;Ahn, Jin-Ho;Park, Young Jun
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.34 no.2
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    • pp.57-66
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    • 2018
  • When developing projects to build facilities to be shared by both military bases and surrounding communities, strategies are needed to achieve two objectives: 1) minimize missteps and opposition from local communities in the process of developing and implementing such projects, and 2) promote cost-benefit optimization and user-satisfaction. With aim of promoting co-operation and co-existence between military bases and adjust communities, this research proposes esthetical factors to be considered in conceiving civil-military sharing facilities. It seeks experts' opinions on the development of civil-military sharing facilities, and examines critical factors (economic feasibility, security, and satisfaction, etc.) for project development as well as building types suitable for shared-use between military bases and local residents. It then establishes a method to prioritize facility-type and narrow down design factors (considerations and restrictions) in project development by applying quantitative analysis. The methodological approach of the research employs the Delphi survey method to quantitatively analyze qualitative information drawn from experts' opinions. At the first round of the survey, facility types, items for consideration and restrictions are drawn, and then at the second round of the survey, criticality of each item is analyzed. Finally, it reaches a conclusion on suitability of facility types for civil-military sharing facilities, and selects project considerations and restrictions when developing this kind of project.

Cyber Risk Management of SMEs to Prevent Personal Information Leakage Accidents (개인정보유출 사고 방지를 위한 중소기업의 사이버 위험관리)

  • So, Byoung-Ki;Cheung, Chong-Soo
    • Journal of the Society of Disaster Information
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    • v.17 no.2
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    • pp.375-390
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    • 2021
  • Purpose: Most of cybersecurity breaches occur in SMEs. As the existing cybersecurity framework and certification system are mainly focused on financial and large companies, it is difficult for SMEs to utilize it due to lack of cybersecurity budget and manpower. So it is necessary to come up with measures to allow SMEs to voluntarily manage cyber risks. Method: After reviewing Cybersecurity market, cybersecurity items of financial institutions, cybersecurity framework comparison and cybersecurity incidents reported in the media, the criticality of cybersecurity items was analyzed through AHP analysis. And cybersecurity items of non-life insurers were also investigated and made a comparison between them. Result: Cyber risk management methods for SMEs were proposed for 20 major causes of cyber accidents. Conclusion: We hope that the cybersecurity risk assessment measures of SMEs in Korea will help them assess their risks when they sign up for cyber insurance, and that cyber risk assessment also needs to be linked to ERM standardization.

Development of a Risk Assessment Tool for Emerging Infectious Diseases (신종감염병의 양적 및 질적 혼합 위험 평가 모델 개발)

  • Woo, Darae;Choi, Eunmi;Choe, Young June;Yeh, Jungyong;Park, Sangshin
    • Health Policy and Management
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    • v.32 no.4
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    • pp.356-367
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    • 2022
  • Background: The emergence of new infectious diseases threatens public health, increasing socioeconomic damage, and national risks. This study aimed to develop an evidence-based risk assessment tool to quickly respond to new infectious diseases. Methods: The risk elements were extracted by reviewing the risk assessment methods of the World Health Organization, United States, Europe, United Kingdom, and Germany, and the validity and priority of elements were determined through expert meetings and Delphi surveys. Then, the scale and level for each risk element were defined and a final score calculation method according to the risk evaluation result was derived. The developed risk assessment tool was verified using data at the time of domestic transmission of an emerging infectious disease. Results: In case of spread of actual infectious diseases, priority is determined based on the criticality of the elements in each area of transmissibility and severity, from which the weighted score of the risk assessment is derived. Then, the risk score for each element was calculated by multiplying the average value of the risk evaluation by its weight and the evaluation risk assessment score for the two areas was calculated. At last, the final score is plotted in a matrix where the x-axis indicates the transmissibility and the y-axis the severity and plotted on the coordinate plane for time series use. Conclusion: With respect to transmissibility and severity, this risk assessment method to respond to new and re-emerging infectious diseases enables rapid and evidence-based evaluation by quantitatively and qualitatively assessing various risk elements.

South-South Collaborations: A Policy Recommendation Model for Sustainable Win-Win Infrastructure Partnerships Based on Sino - Ghana and Nigeria Case.

  • Eshun, Bridget Tawiah Badu;Chan, Albert P.C.;Oteng, Daniel;Antwi-Afari, Maxwell Fordjour
    • International conference on construction engineering and project management
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    • 2022.06a
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    • pp.33-41
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    • 2022
  • Infrastructure procurement has been a major engagement route between China and Africa. This contributes immensely to the gradual infrastructure development seen on the continent. However, maturing discourse purports that these infrastructure collaborations lack intentionality in the continuous development of strategic guidelines and policies for effective implementation despite their uniqueness and criticality. This study proposes that an efficient approach to policy recommendations is through the political and economic analysis (PEA) of these partnerships using public-private partnership (PPP) optics. Unquestionably, these partnerships are representative of the concept of diplomatic transnational public-private partnership (DT-PPP) where infrastructure is procured through the collaboration of public (African governments) and private sector (Chinese state-owned corporations) who provide the managerial, financial, and technical resources for the project implementation. Given the quest for sustainable win-win, this study identifies strategies towards the realization of win-win in the implementation (i.e enablers of win-win) such that fairness and co-benefit, as well as interests, will be achieved. Thus, based on the PEA framework, case scenarios from Ghana and Nigeria using expert interviews identify the criticalities and best practices for the realization of these enablers at the development phase. Findings indicate more effort is required of the public sector (African host countries) in terms of people, structure/institutions, and the implementation processes. Recommendations include improvement of environmental management structures, contract administration procedures, external stakeholders/local community engagement mechanisms, knowledge and technology transfer procedures, and sector-based project operation and maintenance culture and systems. Additionally, actors must have emotional intelligence, good problem-solving abilities, and overall ensure cordial relationships for continued bilateral cooperation.

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Safety Improvements of Guardrail Coating Vehicle Using FMECA and HAZOP (FMECA와 HAZOP을 활용한 가드레일 코팅차량의 안전성 향상)

  • U.P. Chong;H.C. Park;B.C. Ahn;Y.S. Park;D.S. Han;H.J. Chon
    • Journal of the Korea Safety Management & Science
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    • v.25 no.3
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    • pp.73-81
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    • 2023
  • This study uses FMECA (Failure Modes, Effects, and Criticality Analysis) and HAZOP (Hazard and Operability), which are widely applied in industrial areas, among risk assessment methods, and applies them to the same system. While FMECA evaluates system failure conditions and analyzes risks, HAZOP evaluates the system comprehensively by evaluating operational risks that may occur based on system parameters. According to data released by the Ministry of Land, Infrastructure and Transport, as of December 2021, the length of roads in Korea is 113,405 km, and the repair of guardrails that have expired must be fixed urgently in terms of traffic safety. Replacing all of these guardrails with new ones requires a very large cost, but if the guardrails are repaired with a vehicle equipped with the G-Save method, carbon emissions are reduced, the repair period is shortened, and great economic benefits can be obtained. However, risk assessment for guardrail coating vehicles has not been done so far. Focusing on this point, this study aims to evaluate the risk of these coating vehicles and describe the results. Finally, we found that the Risk Priority Numbers(RPN) in the FMECA risk assessment were greatly reduced, and 6 risk factors from HAZOP risk assessment and actions were taken.

Estimation of Economic Impact on the Air Transport Industry based on the Volcanic Ash Dispersion Scenario of Mt. Baekdu (백두산 화산재 확산 시나리오에 따른 항공산업의 경제적 피해 예측)

  • Kim, Su-Do;Lee, Yeonjeong;Yoon, Seong-Min
    • Journal of International Area Studies (JIAS)
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    • v.18 no.3
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    • pp.109-144
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    • 2014
  • In 2010, large areas of European airspace were closed by the volcanic ash generated by the eruption of Icelandic volcano and it disrupted global trade, business and travel which caused a huge economic damage on the air transport industry. This brought concerned about the economic impact by the eruption of Mt. Baekdu volcano. In this paper, we analyze the affected areas of the air transport industry were decided by calculating the PM10 density of volcanic ash changed over time and by determining the safe upper limit of ash density in their airspace. We separate the sales in the air transport industry according to each airline, airport, and month to estimate the direct losses when all flights inside a restricted zone were canceled. Also, we estimate the indirect losses in regional output, income, and value-added of the different major industries using interindustry (input-output) analysis. There is no direct damage from VEI 1 to VEI 5. But when VEI is 6, all flights to and from Yangyang airport will be canceled due to the No Fly Zone. And some flights to and from the airports Gimhae, Ulsan and Pohang will be restricted due to the Time Limited Zone. When VEI is 7, Yangyang, Gimhae, Ulsan, Pohang and Daegu airports will be closed and all flights will be canceled and delayed. During this time, the total economic losses on the air transport industry are estimated at 8.1 billion won(direct losses of about 3.55 billion won, indirect losses of about 4.57 billion won). Gimhae international airport accounted for 92% of the total loss and is the most affected area according to the volcanic ash scenario of Mt. Baekdu.

Building TRMS S/W based on Reliability Centered Maintenance (신뢰성 기반의 유지보수를 위한 TRMS S/W개발)

  • Ahn, E.J.;Lee, K.S.;Lee, K.S.;Kim, S.O.;Yoo, D.Y.;Kim, C.H.;Yoon, H.S.;Lee, I.H.;Oh, S.H.
    • Journal of the Korean Society for Railway
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    • v.13 no.2
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    • pp.159-165
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    • 2010
  • In this paper the TRMS (Tilting Rolling-stock Maintenance System) that applies the concept of RAM (Reliability, Availability, and Maintainability) and RCM (Reliability Centered Maintenance) to Preventive and Corrective Maintenance Policy for TTX (Tilting Train Express) will be discussed. We will briefly introduce the RCM concepts and discus show these concepts and procedures are implemented in the TRMS S/W. In the TRMS S/W there are four modules, System and Operations Information Module, FMECA(Failure Modes, Effects, and Criticality Analysis)module, RAM Information Module, and RCM Analysis Module. The System and Operations Information Module provides the user interface for collection of systems and operations related data and the FMECA module provides a groundwork for the RCM analysis. The algorithms to calculate the reliability and failure rate for Weibull distribution and formulae to calculate the task intervals and task costs are proposed in the RAM and RCM Analysis Module respectively. There is a good possibility of applying RCM to other rolling stock maintenance systems if the benefit that RCM can brings to the maintenance world is fully recognized.

A Study on the Methods of Fault Analysis to Improve Safety in U-Healthcare System for Managing Emergency Rescue for Seniors (시니어들의 응급구난 관리를 위한 U-Healthcare시스템에서 안전성 개선을 위한 결함 분석 방법에 관한 연구)

  • Kim, Gyu-A;Park, Man-Gon
    • Journal of Korea Multimedia Society
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    • v.17 no.2
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    • pp.170-179
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    • 2014
  • Recently the U-Healthcare system has been rapidly advanced to manage emergence rescue for seniors. We can access emergency rescue systems with high quality services anytime, anywhere under ubiquitous healthcare systems. The more the various systems develop, the more software security systems become important. Therefore, the safety-critical system has been widely spread to the world by advancement of the information and communication technologies. There are a lot kind of fault analysis methods to evaluate software security systems. However due to characteristics of software that is not applied by human error, it can be prevented the enormous damages and losses from improving the safety of safety-critical system. So this paper proposes an integration method of FTA and Forward and Backward FMECA. This method has each strength of FTA and FMECA which is visual and numeric in normalization. First, by use of FTA, we can redraw FTA with Forward FMECA and Backward FMECA in consideration of occurrence, severity, detection, correctness, robustness, and security. Also according to value of NRVP at each event, we can modify FTA diagrams as shown critical paths given by severity and occurrence. Also, we propose the improved emergency rescue service platform of ubiquitous healthcare systems through identifying priorities of the criticality according to normalized risk priority values (NRPV).