• Title/Summary/Keyword: reliability and safety

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A Study on the Design of Metaevaluation Model for the Maritime Traffic Safety Assessment Scheme (해상교통안전진단제도의 메타평가 모형설계에 관한 연구)

  • Cho, Kyung-Min;Kong, Gil-Young;Cho, Ik-Soon
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.19 no.4
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    • pp.382-390
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    • 2013
  • The efforts for improving 'Maritime Traffic Safety Assessment Scheme(MTSA scheme)' have continued to the present. At this point, it needs to establish sound MTSA scheme to proceed acceleration step through the comprehensive review and systematic approach. In this study, it aimed to design of Metaevaluation Model for the comprehensive analysis of MTSA scheme with applying theory of the Metaevaluation, that is the evaluation of evaluation. To put it concretely, This research draw a basic model by using Metaevaluation methods like as literature studies, expert reviews, surveys and etc. and proposed a available 'PIP'OU' Metaevaluation Model through verified validity and reliability. This PIP'OU Model is the first proposed Metaevaluation Model in maritime field and it is expected to be used as framework to draw up improvement measure with deriving problem for the MTSA scheme.

Evaluation of Thermal Stability in Neutralization Process of Pigment Plant (안료제조시 중화공정의 열안정성 평가)

  • Lee, Keun-Won;Han, In-Soo;Park, Sang-Hyun
    • Journal of the Korean Society of Safety
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    • v.22 no.4
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    • pp.43-50
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    • 2007
  • Lack of understanding of the process chemistry and thermodynamics are the major reasons that can is lead to thermal runaway reaction in the chemical reaction process. The evaluation of reaction factors and thermal behavior in neutralization process of pigment plant are described in this paper. The experiments were performed in the C 80 calorimeter, and Thermal Screening Unit($TS^{u}$). The aim of the study was to evaluate the results of thermal stability in terms of safety reliability to be practical applications. It suggested that we be proposed safe operating conditions and securities for accident prevention through this study.

A Study on Maintenance Rule for the Maintenance Effectiveness Monitoring (정비 효율성 감시를 위한 정비규정에 관한 연구)

  • 황미정;김길유
    • Journal of the Korean Society of Safety
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    • v.16 no.2
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    • pp.110-116
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    • 2001
  • The objective of the Maintenance Rule (MR) is to require monitoring of the overall continuing effectiveness of licensee maintenance programs to ensure that the safety related and certain nonsafety-related SSCs are capable of performing their intended functions. In Korea, as risk informed applications and regulation become active, the necessity of Performance Based Regulation (PBR) has increased. The objective of this article is to study the effectiveness of MR based on performance and feasibility of MR adoption at Korean Nuclear Power Plants (NPPs) for effective maintenance and regulation.

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On the Study of System Reliability Analysis of Tension Leg Platforms (TLP 해양구조물의 시스템 신뢰성 해석에 관한 연구)

  • Joo-Sung,Lee
    • Bulletin of the Society of Naval Architects of Korea
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    • v.27 no.2
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    • pp.55-62
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    • 1990
  • In this paper, another method for system reliability analysis, called the extended incremental load method, is introduced. The method is an extension of the conventional incremental load method and has been developed aiming at evaluating the probability of system failure(or system reliability) of continuous structures such as floating offshore structures under the multiple loading condition, more realistically considering the post-ultimate behaviour of failed components and directly using the strength formulae of principle components in a structure with employing the modified safety margin equation proposed herein in the system analysis. The method has been applied to the Hutton TLP operated in the Hutton field in the North Sea and a certain variant of the design using the TLP Rule Case Committee type improved strength models. System failure probability and corresponding system reliability indices are derived for a more economical and efficient design. The redundancy characteristics are also addressed. The TLP forms are shown to possess high reserve strength and system safety.

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Determination of the coefficient of variation of parameters for the reliability design of shield tunnel segment lining (쉴드 터널 세그먼트 라이닝의 신뢰성 설계를 위한 변수의 변동계수 결정)

  • Byun, Yoseph;Kim, Do;Lee, Seongwon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.6
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    • pp.875-885
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    • 2019
  • This paper is aimed to suggest the coefficient of variation of the total load on the segment lining and the coefficient of variation of earth pressure in reliability based design of shield tunnel. For this purpose, the statistical characteristics of weathered soil and weathered rock were calculated by analyzing the site survey data of the domestic urban section. The coefficient of variation could be estimated by applying these values to Terzaghi's theory using MCS technique. As a result, the coefficient of variation of rock load for weathered soil and weathered rock was 0.08~0.14. The coefficient of variation for the total load acting on the tunnel was LC1 = 0.38, LC2 = 0.33, and LC3 = 0.37. The proposed coefficients of variation can be used in the reliability-based design of shield tunnel segments.

Development and Validation of an Instrument to Measure High School Students' Disaster Safety Awareness

  • Lee, Soon-Beom;Kong, Ha-Sung
    • International Journal of Internet, Broadcasting and Communication
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    • v.13 no.4
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    • pp.154-168
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    • 2021
  • The purpose of this study is to develop and validate the disaster safety awareness scale for high school students. For this purpose, the previously developed disaster safety awareness scale and related prior research was analyzed. Questionnaire data was collected from March 22 to May 25, 2021 from 1054 students (male: 569, female: 485) in the first, second, and third grades of 5 high schools in 3 cities. Through the process of revising, supplementing, and reviewing the items extracted through preliminary research and preliminary test together with experts and students, a final disaster safety awareness scale consisting of 24 items was developed. This scale consists of four sub-factors: 'disaster prevention', 'disaster response A', 'disaster response B', and 'disaster recovery'. Good reliability and validity were secured through exploratory and confirmatory analyses. The significance of this study is that it laid a basic and objective foundation for high school students' disaster safety awareness research by developing a validated scale in a situation where the development of disaster safety awareness scales for high school students was still insufficient. It can be used as useful data for fire safety education as well as a psychological measurement tool for fostering fire safety awareness.

Risk-informed approach to the safety improvement of the reactor protection system of the AGN-201K research reactor

  • Ahmed, Ibrahim;Zio, Enrico;Heo, Gyunyoung
    • Nuclear Engineering and Technology
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    • v.52 no.4
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    • pp.764-775
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    • 2020
  • Periodic safety reviews (PSRs) are conducted on operating nuclear power plants (NPPs) and have been mandated also for research reactors in Korea, in response to the Fukushima accident. One safety review tool, the probabilistic safety assessment (PSA), aims to identify weaknesses in the design and operation of the research reactor, and to evaluate and compare possible safety improvements. However, the PSA for research reactors is difficult due to scarce data availability. An important element in the analysis of research reactors is the reactor protection system (RPS), with its functionality and importance. In this view, we consider that of the AGN-201K, a zero-power reactor without forced decay heat removal systems, to demonstrate a risk-informed safety improvement study. By incorporating risk- and safety-significance importance measures, and sensitivity and uncertainty analyses, the proposed method identifies critical components in the RPS reliability model, systematically proposes potential safety improvements and ranks them to assist in the decision-making process.

Dynamic Analysis and Structural Safety Evaluation of the Cabinet of a Reactor Safety System (원자로 보호계통 캐비닛의 동해석과 구조 안전성 평가)

  • Lee, Boo-Youn;Cho, Chung-Rae;Kim, Won-Jin;Jeong, Dong-Gwan;Shon, Jae-Youl
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.12 s.177
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    • pp.131-140
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    • 2005
  • Responses of the cabinet of the reactor safety system under seismic leadings are analyzed, its dynamic characteristics and structural reliability being evaluated. Analyzed natural frequencies are compared with those measured from a resonance test. Structural safety of the cabinet is evaluated in consideration of the required response spectrums of the operation-base and safe-shutdown earthquakes. Transient responses of the cabinet are analyzed with input ground acceleration measured during the seismic test, accelerations being extracted at the locations of the main internal parts. The transient responses are compared with those from the seismic test, favorable results being shown.

Performance evaluation of safety-critical systems of nuclear power plant systems

  • Kumar, Pramod;Singh, Lalit Kumar;Kumar, Chiranjeev
    • Nuclear Engineering and Technology
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    • v.52 no.3
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    • pp.560-567
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    • 2020
  • The complexity of safety critical systems of Nuclear Power Plant continues to increase rapidly due its transition from analog to digital systems. It has thus become progressively more imperative to model these systems prior to their implementation in order to meet the high performance, safety and reliability requirements. Timed Petri Nets (TPNs) have been widely used to model such systems for non-functional analysis. The paper presents a novel methodology for the analysis of the performance metrics using PN modeling. The paper uses the isomorphism property of the TPNs and the Markov chains for the performance analysis of the safety critical systems. The presented methodology has been validated on a Shutdown System of a Nuclear Power Plant.

Common safety H/W platform and Establishing safety S/W development environment for Ground railway signal systems (철도용 지상신호설비를 위한 공통 안전 H/W 플랫폼 및 안전 S/W 개발 환경 구축(사례))

  • Kim, Do-Young;Kim, Hyun-Min;Kim, Yun-Bae
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.172-180
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    • 2011
  • When it essentially designs and develops the Railway Signal System H/W and S/W, It requires base to build an environment which the safety of the complete system can be certified objectively. It is not rational choice to progress the safety certification of each of the subsystems to ensure reliability from an economic point of view. Furthermore, Even though H/W and S/W already certificated the safety, In case of changing subsystem to comprise relevant system, The safety certification of its parts newly must proceed. This study to solve these problems covers safety H/W platform which is commonly applicable to composition plan at Ground railway signaling systems such as CBTC, ETCS, CBI and safety-based modeling approach with S/W development tools (SCADE) and certificated O/S (Pike) to build the development environment. In addition, When it designs and develops safety S/W, This study explains structure to separate the data section which for logical operations and logical operations itself and provides guideline to support the certification through minimizing changes to the software.

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