Fault Tree Analysis Based on Dynamic Uncertain Causality Graph

2017 ◽  
Author(s):  
Zhenxu Zhou ◽  
Qin Zhang
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Tree Analysis ◽  
Industrial Systems ◽  
Weapon Systems ◽  
Chemical Systems ◽  
Binary State ◽  
Dynamic Uncertain Causality Graph

Fault Tree Analysis (FTA) has been widely applied to large, complex industrial systems like nuclear power plants, chemical systems, and weapon systems. Events in classical FTA are assumed binary-state and s-independent but multi-state, dependencies and logic cycles may exist within FTs. Moreover, causalities in FTA are assumed deterministic, while sometimes they may be uncertain. This paper applies Dynamic Uncertain Causality Graph (DUCG) in FTA to overcome aforementioned issues. This paper shows that any FT can be mapped into a DUCG graph. And with DUCG representation model and algorithm, additional modeling and analytical power are obtained. Multi-value, dependencies, logic cycles, and non-deterministic causalities in FTA are solved. This paper also depicts how to calculate the importance measurement, predict failure, and diagnose fault. The results reveal the effectiveness and feasibility of this methodology.

Review of Application on Dynamic Fault Tree Method in Nuclear Power Plants

2020 ◽  
Author(s):  
Wu Guohua ◽  
Yuan Diping ◽  
Xiao Yiqing ◽  
Wang Jiaxin
Keyword(s):  
Markov Chain ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Fault Trees ◽  
Tree Analysis ◽  
Dynamic Fault Tree ◽  
Fault State

Abstract Fault tree analysis (FTA) is one of the most important methods of probabilistic risk assessment (PRA). The fault state of the system is taken. While traditional FTA is based on static failure model. FTA is not applicable for systems that include redundant, sequence-related systems. At the same time, nuclear power plants (NPPs) contains a large number of redundant equipment, and FTA is difficult to solve these dynamic problems. Therefore, it is necessary to use dynamic fault tree analysis (DFTA) for PRA. In DFTA research, the modular analysis method was first proposed. The modular method divides the dynamic fault tree into a dynamic fault tree and a static fault tree. Among them, the dynamic fault tree is analyzed using a Markov chain, and the static fault tree is studied using a binary decision diagrams method. However, the shortcomings are that when the system is complicated, the information explosion in the Markov chain is appeared. To solve this problem, a dynamic fault tree is transformed into a Bayesian network. At the same time, to verify the feasibility of the method, Monte Carlo random sampling was used to evaluate the method. Other methods are relatively infrequently studied. In this paper, firstly, status of dynamic fault trees has been investigated. Secondly, each method is analyzed and the problems of dynamic fault tree are described. Finally, a survey and analysis on the dynamic fault tree is finished, and the main problems of the dynamic fault tree are: information explosion; the lack of commercial software to apply to engineering. Through this review, we hope to play a certain guiding role in the subsequent research on dynamic fault trees.

Dynamic Fault Tree Analysis Based on Dynamic Uncertain Causality Graph

2018 ◽  
Author(s):  
Zhenxu Zhou ◽  
Chunling Dong ◽  
Qin Zhang
Keyword(s):  
Fault Tree ◽  
Fault Tree Analysis ◽  
Logic Gates ◽  
Industrial Systems ◽  
Dynamic Fault Tree ◽  
Sequential Logic ◽  
Dynamic Uncertain Causality Graph ◽  
Disjoint Product ◽  
Logical Mapping ◽  
Analytical Approaches

Dynamic Fault Tree (DFT) has drawn attention from comprehensive industrial systems in recent years. Many analytical approaches are developed to analyze DFT, such as Markov Chain based method, Inclusion-Exclusion Rule based method, and Sum-of-Disjoint-Product theory based method. Novel methods such as Bayesian Network and Petri Net are also used to solve DFT. However, Basic events are usually assumed unrepairable and are restricted to specific probabilistic distributions. And some methods may suffer from combination explosion. This paper applies Dynamic Uncertain Causality Graph (DUCG) to analyze DFT to overcome the aforementioned issues. DUCG is a newly proposed Probabilistic Graphic Model for large complex industrial systems which allows for dynamics, uncertainties and logic cycles. The DUCG based methodology can be summarized as event mapping, logical mapping, and numerical mapping. This paper studies how to map the PAND, FDEP, SEQ AND SPARE sequential logic gates into equivalent representations in DUCG. With the DUCG representation mode, one can analyze DFT with algorithms in DUCG. Future work will be done on benchmark tests and on software development.

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.

The reliability of general vague fault-tree analysis on weapon systems fault diagnosis

2005 ◽  
Vol 10 (7) ◽  
pp. 531-542 ◽  
Author(s):  
J.-R. Chang ◽  
K.-H. Chang ◽  
S.-H. Liao ◽  
C.-H. Cheng
Keyword(s):  
Fault Diagnosis ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Tree Analysis ◽  
Weapon Systems

scholarly journals Reliability of sequential systems using the cause—consequence diagram method

2001 ◽  
Vol 215 (3) ◽  
pp. 207-220
Author(s):  
J D Andrews ◽  
L M Ridley
Keyword(s):  
Fault Tree ◽  
Fault Tree Analysis ◽  
Alternative Methods ◽  
Design Stage ◽  
Diagram Method ◽  
Tree Analysis ◽  
Industrial Systems ◽  
Analysis Methodology ◽  
Complete Set ◽  
Large Systems

In many industrial systems, where safety is of the utmost importance, it is necessary that expedient tools for accident analysis are available and employed at the design stage. Such tools must be able to handle large systems in a systematic way and display the factors that are of vital importance for the functionality of the system. The technique of fault tree analysis (FTA) is commonly used to assess the failure probability of such systems. The fault tree represents the failure logic of the system in an inverted tree structure and has the advantage that it provides very good documentation of the way the failure logic was developed. Conventional fault tree quantification requires a number of assumptions regarding the system. One of these is that the basic events in the tree occur independently. This condition is not satisfied when sequential failures are encountered. Employing alternative methods, such as Markov methods, can result in the loss of the documentation that represents the failure logic of the system. The cause-consequence diagram method is a tool that, like fault tree analysis, documents the failure logic but has the extra capability enabling the analysis of systems subject to sequential failures. In addition, the cause-consequence diagram identifies the complete set of system responses to any given initiating event. This paper is concerned with the cause-consequence diagram method and its application to sequentially operating systems. It extends previous work by providing more rigorous guidelines to enable the construction of the diagram and an analysis methodology that can be used when dependencies exist between the events featured in the decision boxes. A new symbol distinguishing between events that exist at a specified point in time and those that occur at that time is introduced to facilitate the analysis.

Dynamic fault tree analysis of auxiliary feedwater system in a pressurized water reactor

Kerntechnik ◽  
2021 ◽  
Vol 86 (2) ◽  
pp. 164-172
Author(s):  
R. A. Fahmy ◽  
R. I. Gomaa
Keyword(s):  
Power Plant ◽  
System Reliability ◽  
Nuclear Power ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Cost Effective ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Tree Analysis ◽  
Dynamic Fault Tree

Abstract The safe and secure designs of any nuclear power plant together with its cost-effective operation without accidents are leading the future of nuclear energy. As a result, the Reliability, Availability, Maintainability, and Safety analysis of NPP systems is the main concern for the nuclear industry. But the ability to assure that the safety-related system, structure, and components could meet the safety functions in different events to prevent the reactor core damage requires new reliability analysis methods and techniques. The Fault Tree Analysis (FTA) is one of the most widely used logic and probabilistic techniques in system reliability assessment nowadays. The Dynamic fault tree technique extends the conventional static fault tree (SFT) by considering the time requirements to model and evaluate the nuclear power plant safety systems. Thus this paper focuses on developing a new Dynamic Fault Tree for the Auxiliary Feed-water System (AFWS) in a pressurized water reactor. The proposed dynamic model achieves a more realistic and accurate representation of the AFWS safety analysis by illustrating the complex failure mechanisms including interrelated dependencies and Common Cause Failure (CCF). A Simulation tool is used to simulate the proposed dynamic fault tree model of the AFWS for the quantitative analysis. The more realistic results are useful to establish reliability cantered maintenance program in which the maintenance requirements are determined based on the achievement of system reliability goals in the most cost-effective manner.

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