Fault trees - problems and the modern state of investigations

Journal Article · Sun Jan 01 04:00:00 EST 1995 · Cybernetics and Systems Analysis

OSTI ID:441172

Kuznetsov, N Yu

The main aim of this article is to describe the modern state of fault tree technique and to show the pricipal difficulties arising by the analysis of large and complex fault trees containing many so-called replicated (or repeated) gates and events. It is also shown that usual bottom-up algorithms based on the standard modularization technique with truncation of low-probability cut sets can lead to great computer time expenditures with a large upper bound for the probability of system failure due to truncated cut sets ({open_quotes}truncation error{close_quotes}). We present also a new method of multilevel representation of fault trees with replicated gates. This method enables us to find and simplify cut sets on the level of gates subsequently descending from the higher to the lower level of fault tree representation. The program FAMOCUTN CUT sets for large fault trees with Negated and/or replicated gates is shortly described. This program is based both on the idea of the multi-level fault tree representation and on the most advanced ideas which were proposed in recent years. The further analytical reliability evaluation is made by the program CUTQN (analytical calculation of system unavailability by Quantification of module CUT sets) using the module cut sets as the input dates. In the last section we consider four examples, the first of which illustrates the general idea of the fault tree multilevel representation; computer codes are illustrated by three examples of real systems taken from Deutsche Risikostudie Kernkraftwerke, Phase B.

• OSTI ID: 441172
• Journal Information: Cybernetics and Systems Analysis, Journal Name: Cybernetics and Systems Analysis Journal Issue: 3 Vol. 30; ISSN CYASEC; ISSN 1060-0396
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
EVALUATION
FAULT TREE ANALYSIS
PROBABILITY
RELIABILITY
SYSTEM FAILURE ANALYSIS