Analysis and assessment of the risk of accidents of a structure as a system by the method of "Fault Tree Analysis" on the example of a nuclear power facility under seismic impact

2021 ◽  
pp. 78-93
Author(s):  
Diana V. Zenchenkova ◽  
Sergei M. Travin
Keyword(s):  
Nuclear Fuel ◽  
Nuclear Power ◽  
Spent Nuclear Fuel ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Building Structures ◽  
Nuclear Power Facility ◽  
Tree Analysis ◽  
Power Facility ◽  
Seismic Impact

The article discusses a method for analyzing the risk assessment of failures of the structure as a system by developing a "Fault Tree Analysis". Formulas were proposed for the numerical estimation of the probability of system failure, taking into account the stochastic dependence of the failures of its elements. On the example of a nuclear power facility, a "wet" stand-alone storage facility for spent nuclear fuel, an analysis of possible scenarios of a facility failure was carried out, a "Fault Tree Analysis" was developed and calculated under seismic impact. It has been determined that the risk of structure as a system under seismic impact is determined by the risk of falling process equipment and building structures on the overlap of storage compartments or stored nuclear fuel. To increase the safety of building structures under seismic impact, it is necessary to pay special attention to the design features of the frame part and the interface between the monolithic storage compartment and the frame part, as the most vulnerable link.

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.

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.

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 AN INTELLIGENT SYSTEM BY FUZZY RELIABILITY ALGORITHM IN FAULT TREE ANALYSIS FOR NUCLEAR POWER PLANT PROBABILISTIC SAFETY ASSESSMENT

2014 ◽  
Vol 13 (03) ◽  
pp. 1450017 ◽  
Author(s):  
JULWAN HENDRY PURBA ◽  
JIE LU ◽  
GUANGQUAN ZHANG
Keyword(s):  
Quantitative Data ◽  
Nuclear Power ◽  
Safety Assessment ◽  
Intelligent System ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Software Systems ◽  
Analysis Software ◽  
Fuzzy Reliability ◽  
Tree Analysis

Fault tree analysis for nuclear power plant probabilistic safety assessment is an intricate process. Personal computer-based software systems have therefore been developed to conduct this analysis. However, all existing fault tree analysis software systems only accept quantitative data to characterized basic event reliabilities. In real-world applications, basic event reliabilities may not be represented by quantitative data but by qualitative justifications. The motivation of this work is to develop an intelligent system by fuzzy reliability algorithm in fault tree analysis, which can accept not only quantitative data but also qualitative information to characterized reliabilities of basic events. In this paper, a newly-developed system called InFaTAS-NuSA is presented and its main features and capabilities are discussed. To benchmark the applicability of the intelligent concept implemented in InFaTAS-NuSA, a case study is performed and the analysis results are compared to the results obtained from a well-known fault tree analysis software package. The results confirm that the intelligent concept implemented in InFaTAS-NuSA can be very useful to complement conventional fault tree analysis software systems.

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. 

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