Development of dynamic fault tree model for reactor protection system

2020 ◽  
Author(s):  
Rania A. Fahmy
Keyword(s):  
Fault Tree ◽  
Protection System ◽  
Tree Model ◽  
Dynamic Fault Tree ◽  
Reactor Protection System

scholarly journals Modelling and Resolution of Dynamic Reliability Problems by the Coupling of Simulink and the Stochastic Hybrid Fault Tree Object Oriented (SHyFTOO) Library

Information ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 283 ◽  
Author(s):  
Chiacchio ◽  
Aizpurua ◽  
Compagno ◽  
Khodayee ◽  
D’Urso
Keyword(s):  
Deterministic Model ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Object Oriented ◽  
Software Library ◽  
Tree Model ◽  
Dynamic Reliability ◽  
Simulink Model ◽  
Dynamic Fault Tree ◽  
Dependability Analysis

Dependability assessment is one of the most important activities for the analysis of complex systems. Classical analysis techniques of safety, risk, and dependability, like Fault Tree Analysis or Reliability Block Diagrams, are easy to implement, but they estimate inaccurate dependability results due to their simplified hypotheses that assume the components’ malfunctions to be independent from each other and from the system working conditions. Recent contributions within the umbrella of Dynamic Probabilistic Risk Assessment have shown the potential to improve the accuracy of classical dependability analysis methods. Among them, Stochastic Hybrid Fault Tree Automaton (SHyFTA) is a promising methodology because it can combine a Dynamic Fault Tree model with the physics-based deterministic model of a system process, and it can generate dependability metrics along with performance indicators of the physical variables. This paper presents the Stochastic Hybrid Fault Tree Object Oriented (SHyFTOO), a Matlab® software library for the modelling and the resolution of a SHyFTA model. One of the novel features discussed in this contribution is the ease of coupling with a Matlab® Simulink model that facilitates the design of complex system dynamics. To demonstrate the utilization of this software library and the augmented capability of generating further dependability indicators, three different case studies are discussed and solved with a thorough description for the implementation of the corresponding SHyFTA models.

A Novel Weakest t-Norm based Fuzzy Importance Measure for Fuzzy Fault Tree Analysis of Combustion Engineering Reactor Protection System

2019 ◽  
Vol 27 (06) ◽  
pp. 949-967 ◽  
Author(s):  
Mohit Kumar
Keyword(s):  
Fault Tree ◽  
Fault Tree Analysis ◽  
Protection System ◽  
Importance Measure ◽  
Fuzzy Arithmetic ◽  
Tree Analysis ◽  
Uncertainty Range ◽  
Expert Opinions ◽  
Fuzzy Fault Tree Analysis ◽  
Reactor Protection System

Recently, a new fuzzy fault tree analysis (FFTA) has been developed to propagate and quantify the epistemic uncertainties occurring in qualitative data such as expert opinions or judgments. It is well known that the weakest triangular norm (Tw) based fuzzy arithmetic operations preserve the shape of the fuzzy numbers, provide more exact fuzzy results and effectively reduce uncertainty range. The objective of this paper is to develop a novel Tw-based fuzzy importance measure to identify the critical basic events in FFTA. The proposed approach has been demonstrated by applying it to a case study to identify the critical components of the Group 1 of the U.S. Combustion Engineering Reactor Protection System (CERPS). The obtained results are then compared to the results computed by the existing well-known importance measures of conventional as well as FFTA. The computed results confirm that the proposed Tw -based importance measure is feasible to identify the critical basic events in FFTA in more exact way.

Reliability Analysis of Plug Door System Based on Dynamic Fault Tree

2014 ◽  
Vol 627 ◽  
pp. 207-211
Author(s):  
Yan Hui Wang ◽  
Li Feng Bi ◽  
Li Jie Li
Keyword(s):  
Reliability Analysis ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Deep Understanding ◽  
Structural Redundancy ◽  
Tree Model ◽  
Dynamic Fault Tree ◽  
Working Principle ◽  
Ontology Module ◽  
Markov Method

The plug door system is an important guarantee of the safe operation of the emu, since it has structural redundancy, correlation function and fault dynamic characteristics, this paper uses the dynamic fault tree analysis method for reliability analysis. In deep understanding of the basis of the structure and working principle of the plug door, dynamic fault tree model is established by the way of structure ontology, Module iteration is introduced , and the Markov method is adopted to solve the reliability. At the last, we obtained the equipment failure rate and the reliability of the whole system.

Research on the Reliability of Digital Instrumentation and Control System of Nuclear Power Plant Based on Dynamic Flowgraph Methodology

2017 ◽  
Author(s):  
Chen Zhuo ◽  
Zhao Bo ◽  
Yang Jian ◽  
Sun Jin-long
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Failure Modes ◽  
Fault Tree ◽  
Protection System ◽  
Digital Instrumentation ◽  
And Control ◽  
Reactor Protection System ◽  
Tree Approach

With the development of information and computer technology, the Digital Instrumentation and Control (I&C) System has been widely used in nuclear power plants, which leads the tendency of NPPS’ construction and rebuilding on digital I&C system. As an approximate approach, conventional fault tree approach has been used quite often in the analysis of nuclear power plants’ Probability Safety Assessment (PSA), which combine with system components’ failure modes in order to modeling the digital system’s failure. However, for the reason that conventional fault tree approach has a great disadvantage on analyzing the reliability of digital I&C system, which may not be able to fully describe the dynamic behavior of digital I&C system with significant hardware/software/human action process interaction, multi-failure modes and logic loops, it cannot carry on effective modeling and evaluation of digital I&C system. Therefore it is necessary to establish some dynamic approaches to modeling digital I&C system. As a new probability safety analysis method, Dynamic Flowgraph Methodology (DFM) can model the relationship between time sequence and system variables because of its dynamic property. Therefore, DFM can be used to analyze the impact of software failure, hardware failure and external environment, which are closely related to the reliability of the whole system. In the first place, this paper introduces the theoretical basis, model elements and the modeling procedures of DFM and demonstrates how Dynamic Flowgraph Methodology (DFM) can be applied to Reactor Protection System with interactions between hardware/software and physical properties of a controlled process. Meanwhile, in this case, DFM and fault tree methodologies are both used to conduct the PSA for the same top event by calculating the probability of it and finding out the prime implicants of DFM and minimal cutsets of conventional fault tree. During the process of analysis, we mainly evaluate the reliability of reactor trip function of Reactor Protection System (RPS) by using DFM and conventional fault tree approach and mainly focus on modeling the four-way-redundant voting logic and the reactor trip breaker logic. Finally, through the comparison of this two methods and model results, it is concluded that there is a distinct advantage of DFM over conventional fault tree approach by using multi-logic to fully display the fault mode and utilizing decision table to describe the interaction between software and hardware. In general, conclusion can be drawn that, as a dynamic approach, Dynamic Flowgraph Methodology could be more accuracy and effective than conventional fault tree approach in analysis, ensuring the reliability and safety of the whole digital I&C system.

Assessing the Risk of Noncompliance in Wastewater Treatment

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1411-1420 ◽  
Author(s):  
S. H. Choudhury ◽  
S. L. Yu ◽  
Y. Y. Haimes
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Fault Tree ◽  
Treatment Plant ◽  
Risk Identification ◽  
System Component ◽  
System Failure ◽  
Tree Model ◽  
Risk Quantification ◽  
Failure Probabilities

This paper presents an integrated methodology that allows determining the probability of noncompliance for a given wastewater treatment plant. The methodology applies fault-tree analysis, which uses failure probabilities of individual components, to predict the overall system failure probability. The methodology can be divided into two parts : risk identification and risk quantification. In risk identification, the key components in the system are determined by analyzing the contribution of individual component failures toward system failure (i.e., noncompliance). In risk quantification, a fault-tree model is constructed for the particular system, component failure probabilities are estimated, and the fault-tree model is evaluated to determine the probability of occurrence of the top event (i.e., noncompliance). A list can be developed that ranks critical events on the basis of their contributions to the probability of noncompliance. Such a ranking should assist managers to determine which components require most attention for a better performance of the entire system. A wastewater treatment plant for treating metal-bearing rinse water from an electroplating industry is used as an example to demonstrate the application of this methodology.

The Failure Analysis and Processing of Digital Reactor Protection System

2013 ◽  
Author(s):  
Jun Zhao ◽  
Xing Zhou ◽  
Jin Hu ◽  
Yanling Yu
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Phase 1 ◽  
Protection System ◽  
Pressurized Water Reactor ◽  
Communication Failure ◽  
Pressurized Water ◽  
Power Failure ◽  
Self Test ◽  
Reactor Protection System

The Qinshan Nuclear Power Plant phase 1 unit (QNPP-1) has a power rating of 320 MWe generated by a pressurized water reactor that was designed and constructed by China National Nuclear Corporation (CNNC). The TELEPERM XS I&C system (TXS) is to be implemented to transform analog reactor protection system (RPS) in QNPP-1. The paper mainly describes the function, structure and characteristic of RPS in QNPP-1. It focuses on the outstanding features of digital I&C, such as strong online self-test capability, the degradation of the voting logic processing, interface improvements and CPU security. There are some typical failures during the operation of reactor protection system in QNPP-1. The way to analyze and process the failures is different from analog I&C. The paper summarizes typical failures of the digital RPS in the following types: CPU failure, communication failure, power failure, Input and output (IO) failure. It discusses the cause, risk and mainly processing points of typical failure, especially CPU and communication failures of the digital RPS. It is helpful for the maintenance of the system. The paper covers measures to improve the reliability of related components which has been put forward effective in Digital reactor protection system in QNPP-1. It will be valuable in nuclear community to improve the reliability of important components of nuclear power plants.

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