scholarly journals The Implementation of Importance Measure Approaches for Criticality Analysis in Fault Tree Analysis: A Review

2018 ◽  
Vol 20 (1) ◽  
pp. 1 ◽  
Author(s):  
Julwan Hendry Purba ◽  
Deswandri Deswandri
Keyword(s):  
Nuclear Power ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Importance Measure ◽  
Clear Understanding ◽  
Tree Analysis ◽  
Risk Reduction Measure ◽  
Safety Systems ◽  
Risk Managers ◽  
Criticality Analysis

THE IMPLEMENTATION OF IMPORTANCE MEASURE APPROACHES FOR CRITICALITY ANALYSIS IN FAULT TREE ANALYSIS: A REVIEW.Fault tree analysis (FTA) has been widely applied in nuclear power plant (NPP) probabilistic safety assessment to evaluate the reliability of a safety system. In FTA, criticality analysis is performed to identify the weakest paths in the system designs and components. For this purpose, an importance measure approach can be applied. Risk managers can apply information obtained from this analysis to improve safety by implementing risk reduction measure into the new design or build a more innovative design. Various importance measure approaches have been developed and proposed for criticality analysis in FTA. Each important measure approach offers specific purposes and advantages but has limitations. Therefore, it is necessary to understand characteristics of each approach in order to select the most appropriate approach to reach the purpose of the study. The objective of this study is to review the current implementations of importance measure approaches to rank individual basic events and/or minimal cut sets regarding their contributions to the unreliability or unavailability of NPP safety systems. This study classified importance measure approaches into two groups, i.e. probability–based importance measure approaches and fuzzy–based importance measure approaches. This study concluded that clear understanding of the purpose of the study, the type of reliability data at hands, and the uncertainty in the calculation need to be considered prior to the selection of the appropriate importance measure approach to the study of interest. 

Application of Fuzzy Fault-Tree Analysis to Assess the Reliability of a Protection System for a Switchyard

2008 ◽  
Vol 9 (4) ◽  
Author(s):  
Ying-Yi Hong ◽  
Lun-Hui Lee ◽  
Heng-Hsing Cheng
Keyword(s):  
Power Plant ◽  
Fuzzy Set ◽  
Nuclear Power ◽  
Fault Tree ◽  
Reliability Assessment ◽  
Fault Tree Analysis ◽  
Protection System ◽  
Importance Measure ◽  
Tree Analysis ◽  
Fuzzy Fault Tree Analysis

This paper proposed a method for reliability assessment of the protection system for a switchyard by fault-tree analysis considering uncertainty of unavailability for an element. Unavailability of an element with uncertainty is expressed with the fuzzy set. The fault-tree analysis incorporated with the fuzzy set is employed to conduct the reliability assessment. The importance of elements influencing reliability can be achieved by the Fuzzy Importance Measure. Compared with traditional methods, the fault-tree analysis requires less computation. In this paper, a 345 kV switchyard in the 3rd nuclear power plant in Taiwan serves as an example for illustrating the results of the proposed method.

scholarly journals Evaluations on adequacy and utility of Failure Modes and Effects and Criticality Analysis and Fault Tree Analysis methodologies applied to civil RPAS systems

2018 ◽  
Vol 233 ◽  
pp. 00002 ◽  
Author(s):  
Federica Bonfante ◽  
Matteo D. L. Dalla Vedova ◽  
Paolo Maggiore
Keyword(s):  
Information Science ◽  
Failure Modes ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Economic Benefits ◽  
Tree Analysis ◽  
Research Activities ◽  
Remotely Piloted Aircraft ◽  
Critical Issues ◽  
Criticality Analysis

This paper is on the Failure Modes and Effects and Criticality Analysis and Fault Tree Analysis methodologies applied to the equipment and functional subsystems of Remotely Piloted Aircraft Systems (RPAS). Such aerial vehicles have been used almost exclusively for military purposes until the first decade of the 2000s. The debate then was focused both on technical and regulatory issues and research activities. Thanks to this renewed interest on unmanned systems and thanks to relatively recent improvements in information science, telecommunication, electronics and material science a strong awareness on the potential extension of unmanned technologies to civil applications arose up. A variety of economic benefits has been recognized by the aviation community from the civil use of RPAS, but, due to the absence of the pilot on board both military and civilian RPAS have always been relegated to fly into segregated airspaces. Technical potentialities of RPAS will be fully exploited integrating them into controlled airspaces in a reliable and safe way. This paper shows an example of application of FMECA and FTA to RPAS and discuss the most critical issues related to the performed analyses as well as possible future developments of this work.

The Fault Tree Analysis on Auxiliary Feedwater Pump Room Ventilation System in Pressurized Water Reactor Power

2013 ◽  
Author(s):  
Yang Li ◽  
Chen Hang
Keyword(s):  
Nuclear Power ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Easy Access ◽  
Main Function ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Tree Analysis ◽  
Water Reactor ◽  
Mandatory Requirement

Main function of HVAC is to remove heat from equipment and pipeline, hold the inner condition, maintain an ambient temperature and humidity that keep the equipments function properly and easy access. Although regulation is no mandatory requirement of redundant equipment design and preservation function in case of specified disaster or man-made accident. In fact, It does be influenced by the incident whether partial failure or full. The hazard factor determination and qualitative analysis are based on fault tree analysis through simulated mode from selected the typical system. The identification of accident cause, hazard cause and fault mode is essential for improving system reliability. According the analysis result, It will be optimization factor such as installation and design process, maintenance ability, material plan, corrosion preventing. It’s helpful to control hazard under accepted level. This method given in the article is a new way to treat HVAC system in pressurized water reactor nuclear power. It hopes that this method will lead to reduce accident loss, save maintenance fee, bring economic benefits and improve the risk of nuclear power.

scholarly journals Operational failure assessment of Remotely Operated Vehicle (ROV) in harsh offshore environments

Pomorstvo ◽  
2021 ◽  
Vol 35 (2) ◽  
pp. 275-286
Author(s):  
Samson Nitonye ◽  
Sidum Adumene ◽  
Charles Ugochukwu Orji ◽  
Anietie Effiong Udo
Keyword(s):  
Failure Modes ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Importance Measure ◽  
Remotely Operated Vehicle ◽  
Arctic Water ◽  
Tree Analysis ◽  
Integrity Assessment ◽  
Failure Assessment ◽  
Operational Failure

For an effective integrity assessment of marine robotic in offshore environments, the elements’ failure characteristics need to be understood. A structured probabilistic methodology is proposed for the operational failure assessment (OFA) characteristics of ROV. The first step is to assess the likely failure mode of the ROV system and its support systems. This captures the interaction and failure induced events during operation. The identified potential failure modes are further developed into logical connectivity based on the cause-effect relationship. The logical framework is modeled using the fault tree analysis technique to predict the ROV operational failure probability in an uncertain harsh environment. The fault tree analysis captured the logical relationship between the primary, intermediate, and top events probability. The importance measure criteria were adopted to identify the most probable events, links, and their importance on the failure propagation. The model was demonstrated with an ROV for deep arctic water subsea operations. The result identified the control system, communication linkages, human factor, among others, as most critical in the ROV operational failure. The methodology’s application provides core information on the Mean time between failure (MTBF) of the ROV system that could aid integrity management and provides a guide on early remedial action against total failure.

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