Advances on Fault Tree and Event Tree Techniques

Author(s):  
S. Contini ◽  
A. Poucet
Keyword(s):  
1997 ◽  
Vol 21 ◽  
pp. S923-S928 ◽  
Author(s):  
D.H. Kuo ◽  
D.S. Hsu ◽  
C.T. Chang
Keyword(s):  

Author(s):  
Yuko O. Mizuno ◽  
Katsunori Ogura ◽  
Hisashi Ninokata ◽  
Lawrence E. Conway

A preliminary level-1 probabilistic safety assessment of the IRIS plant has been performed. The first focus is on five internal initiating events, such as primary system break (loss-of-coolant accident and steam generator tube rupture) and transients (secondary system line break and loss-of-off-site power). In this study, the event tree for each initiating event was developed and the fault tree analysis of the event tree headings was carried out. In particular, since one of the IRIS safety systems, the passive emergency heat removal system, is unique to the IRIS plant and its reliability is key to the core damage frequency evaluation, it received more extensive fault-tree development. Finally the dominant sequences that lead to severe accidents and the failures in the main and support systems are identified.


2021 ◽  
Author(s):  
Zlatko Zafirovski ◽  
Vasko Gacevski ◽  
Zoran Krakutovski ◽  
Slobodan Ognjenovic ◽  
Ivona Nedevska

The intense demand and construction of tunnels is accompanied by uncertainties. The reason for appearance of uncertainties are the complex solutions and conditions for these structures. Location and dimensions are becoming more challenging, and the construction is predicted in complexed geological conditions, leading to application of new approaches, methodologies and technologies by the engineers. Most of the uncertainties and unwanted events in tunnelling occur in the construction phase, which generally leads to economic consequences and time losses. For easier handling of the uncertainties, they should be anticipated and studied within a separate part of each project. One of the newer approaches to dealing with uncertainties is hazard and risk assessment and defining ways to deal with them i.e. management. Hazards and risks can be analysed qualitatively and quantitatively. The quantitative analysis, examines the causes and consequences in more detail way and gives explanation of the dependencies. With the quantitative approach, a more valuable information for decision-making can be provided. There are various models and methods used for the quantification of hazards and risks. This paper presents a methodology in which the fault tree analysis and event tree analysis are used in combination to obtain quantitative results. The fault tree analysis is used for assessment of various hazards and the different ways and reasons that cause them. The event tree analysis is a method for assessing the possible scenarios, which follow after a certain hazard i.e. the consequences that may occur in the project. These trees represent graphic models combined with a mathematical (probabilistic) model, which give the probability of occurrence of the risks.


Author(s):  
Ernie Kee ◽  
Fatma Yilmaz ◽  
Don Wakefield ◽  
Steve Epstein

The South Texas Project (STP) balance of plant (BOP) model for production losses has been converted from an Excel-based software application that uses minimal cutsets from a single large fault tree, to a set of small fault trees used within a risk analysis tool, Riskman® [8]. The Riskman® application provides estimates of interest to plant investors and owners such as potential production losses and plant profitability, as well as production reliability and quality (loss frequency, type of loss, loss duration and standard economic risk metrics). The BOP models and methodologies developed are applicable to both fault-tree linking and event-tree linking styles of risk analysis. The STP BOP model is developed to support configuration risk management in two categories: 1) trip risk and concomitant core damage frequency; and 2) non-trip production risk. The primary purpose for the conversion work is to make the STP BOP model framework and application platform consistent with the STP probabilistic risk assessment model. In the course of the conversion, improvements to the Riskman® software have been implemented and techniques to more efficiently produce BOP modeling (fault tree) improvements were developed. Better methods to accurately calculate initiating event frequencies are studied. New data types added to support BOP modeling are described.


Sign in / Sign up

Export Citation Format

Share Document