Safety analysis of autonomous systems by extended fault tree analysis

2007 ◽  
Vol 21 (2-3) ◽  
pp. 287-298 ◽  
Author(s):  
Jan Åslund ◽  
Jonas Biteus ◽  
Erik Frisk ◽  
Mattias Krysander ◽  
Lars Nielsen
Keyword(s):  
Autonomous Systems ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Safety Analysis ◽  
Tree Analysis

Quantitative safety analysis of a laboratory-scale bioreactor for hydrogen sulfide biotreatment using fault tree analysis

2013 ◽  
Vol 32 (4) ◽  
pp. 376-386 ◽  
Author(s):  
Mohamed A. Zytoon ◽  
Ahmed H. El-Shazly ◽  
Madbuli H. Noweir ◽  
Abdulrahim A. Al-Zahrani
Keyword(s):  
Hydrogen Sulfide ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Safety Analysis ◽  
Laboratory Scale ◽  
Tree Analysis

scholarly journals Safety Analysis Technique for System with Limited Data: Case Study of the Multipurpose Research Reactor in Indonesia

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1975
Author(s):  
Heri Hermansyah ◽  
Anggraini Ratih Kumaraningrum ◽  
Julwan Hendry Purba ◽  
Edison ◽  
Masafumi Yohda
Keyword(s):  
Research Reactor ◽  
Cooling System ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Safety Analysis ◽  
Energy Agency ◽  
Actual Performance ◽  
Tree Analysis ◽  
Event Probability ◽  
Generic Data

Fault tree analysis (FTA) is frequently applied to deductively evaluate the safety systems of complex engineering systems such as chemical industries or nuclear facilities. To perform this analysis, generic data are commonly used due to the limitation of historical failure data of the system being evaluated. However, generic data have a degree of uncertainty and hence cannot represent the system’s actual performance. In addition, generic data are not applicable to older components due to the aging process, which obviously degrades the reliability of those components. To deal with this limitation, another safety analysis method, called fuzzy fault tree analysis (FFTA), has been proposed. The purpose of this study is to apply FFTA to evaluate the performance of the primary cooling systems of G.A. Siwabessy Multipurpose Reactor (RSG-GAS). RSG-GAS is a research reactor, which belongs to the National Nuclear Energy Agency of Indonesia (BATAN). Expert justifications were used to evaluate the failure occurrences of basic events in the primary cooling system of the RSG–GAS through questionnaires. The assessment by experts is in the form of qualitative data, which are then converted into quantitative data by applying FFTA. Then, the top event probability generated from FFTA was applied to calculate the event probability using event tree analysis (ETA). It was obtained that the highest event probability was 4.304 × 10−8/year. Since it complies with The International Atomic Energy Agency (IAEA) specified core damage frequency (CDF) limit, i.e., not greater than 10−5/year of reactor operation, the reactor is safe to operate.

A fault tree analysis-based method of railway traffic control systems safety assessment (Metoda oceny bezpieczeństwa systemów sterowania ruchem kolejowym z wykorzystaniem FTA)

2020 ◽  
Vol 128 ◽  
pp. 49-57
Author(s):  
Tomasz Ciszewski ◽  
Waldemar Nowakowski ◽  
Zbigniew Łukasik
Keyword(s):  
Risk Assessment ◽  
Traffic Control ◽  
Safety Assessment ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Safety Analysis ◽  
Level Crossing ◽  
Tree Analysis ◽  
Signaling Systems ◽  
Railway Traffic

Railway traffic control and signaling systems are safety-related, and thus it is crucial to provide them with an appropriate level of safety. Technological development has led to an increase in the functionality and reliability of these systems, taking into account the high safety requirements. Therefore, the operations involving the design, construction, and maintenance of railway traffic control and signaling systems should include a safety analysis. The safety analysis of railway traffic and signaling systems assumes that a primary event may cause a series of intermediate events, which then may lead to a disaster causing significant material losses and fatalities. Due to the random nature of the occurrences of the adverse events (failures, human errors), the probabilistic methods are often used to estimate risk. One of the risk assessment methods is Fault Tree Analysis (FTA). The authors of the paper conducted a qualitative safety analysis of level crossing protection systems using the FTA method. The requirements for the level crossing protection system were described, which we then used to write out FTA diagrams. The specific technical and quality requirements for railway traffic control and signaling systems result from the need to ensure a high safety level. Risk assessment is a required step in the evaluation of the safety and reliability of these systems. The authors of the paper applied the FTA method to the safety assessment of the level crossing protection system. The obtained results should be helpful in the process of design new railway traffic control and signaling systems. Systemy sterowania ruchem kolejowym są systemami związanymi z bezpieczeństwem, a tym samym bardzo ważnym aspektem jest dążenie do zapewnienia przez nie odpowiednie-go poziomu bezpieczeństwa. Wraz z rozwojem technologicznym następował wzrost funkcjonalności i niezawodności tych systemów, przy uwzględnieniu wysokich wymagań w odniesieniu do bezpieczeństwa. Dlatego też, działania polegające na projektowaniu, konstruowaniu i utrzymaniu systemów sterowania ruchem kolejowym powinny uwzględniać analizę bezpieczeństwa. W takiej analizie zakłada się, że zdarzenie pierwotne może wywołać ciąg zdarzeń wtórnych, które następnie mogą doprowadzić do katastrofy, niosącej ze sobą duże straty materialne i śmierć ludzi. Ze względu na losowy charakter występowania zdarzeń niepożądanych (uszkodzenie, błąd ludzki), często przy szacowaniu ryzyka wykorzystuje się w opis probabilistyczny. Jedną z metod szacowania ryzyka jest metoda FTA (Fault Tree Analysis). Autorzy artykuły przy wykorzystaniu metody FTA przeprowadzili analizę jakościową bezpieczeństwa przejazdów kolejowych wyposażonych w systemy zabezpieczenia. Opisano wymagania dla systemu zabezpieczenia przejazdu, które następnie posłużyły do zbudowania drzew FTA. Specyficzne wymagania techniczne i jakościowe dla systemów sterowania ruchem kolejowym wynikają z konieczności zapewnienia wysokiego poziomu bezpieczeństwa. W celu oceny bezpieczeństwa i niezawodności tych systemów, musimy podejmować działania w zakresie oceny ryzyka. Autorzy publikacji zastosowali metodę FTA do oceny bezpieczeństwa systemu zabezpieczenia przejazdu. Uzyskane wyniki mogą być pomocne w procesie konstruowania nowych systemów sterowania ruchem kolejowym. null

Application of Fault Tree Analysis for Signaling Systems

2015 ◽  
Author(s):  
Sofia K. Georgiadis
Keyword(s):  
Failure Analysis ◽  
Failure Modes ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Safety Analysis ◽  
Valuable Insight ◽  
Analysis Tool ◽  
Tree Analysis ◽  
Signaling Systems ◽  
Analysis Techniques

Fault Tree Analysis (FTA) is one of the key safety evaluation techniques used by New York City Transit (NYCT). First developed over 50 years ago, this technique continues to provide valuable insight for failure analysis of systems. Its use is widespread in safety-critical systems analysis across industry boundaries, including defense, nuclear, aerospace, chemical [1], and transportation industries. FTAs provide a systematic, top-down methodology to safety analysis. As such, it complements other safety analysis techniques, such as Failure Modes Effect Analysis (FMEA), which is a bottom-up failure analysis [2]. Formal Methods analyses, including Theorem Proving and Model Checking, are powerful development and analysis methodologies, both used by NYCT, that provide assurance of product’s correctness and safety. With these other safety analysis techniques, the FTA continues to play a key role in the NYCT Safety Program. This paper will examine how NYCT uses FTAs for the safety analysis of microprocessor-based signaling systems. FTAs are used by NYCT throughout the system lifecycle. Initially, during the system development phase, NYCT requires system suppliers to develop Fault Tree Analyses of their systems, as a requirement for NYCT safety certification and deployment. For the system maintenance phase, NYCT uses the outputs of suppliers’ analyses to develop and enforce maintenance and operational procedures. In this manner, NYCT’s use of FTA provides full lifecycle value by providing design, maintenance, and operational insight into the causes of hazardous events. Through the examination of example fault trees and an overview of the FTA process, this paper will present the NYCT’s implementation of this powerful analysis tool, and will describe the benefits gained from using this methodology.

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