A very high level of availab ility is crucial to the economic operation of modern power plants, in view of the huge expenditure associated with their failures. Th is paper deals with the availab ility analysis of a Lube oil system used in a combined cycle power plant. The system is modeled as a Generalized Stochastic Petri Net (GSPN) taking into consideration of partial failures of their subsys...

Abstract: The rapid advancements in science and technology aggravate the need for the optimal design of modern systems, aiming to achieve the maximum system reliability while meeting some resource constraints (e.g., cost, weight, etc). In this paper, we consider the system reliability optimization for series-parallel systems subject to commoncause failures (CCF). Unlike traditional approaches t...

This paper deals with cost – effective optimum design of parallel redundant system. The components in the redundant system are assumed to be identical and failure time follows exponential distribution. This paper suggests optimal spares (S*) required for redundant configuration in parallel redundant system. The results are presented for common cause failures with fault coverage.

Traditionally, fault tree analysis has been the leading method for reliability analysis of complex systems. However, dynamic properties of systems cannot always be described with adequate accuracy using fault trees. Dynamic reliability analysis has been studied widely since the 1990s. Some dynamic calculation tools have been developed but they cannot compete with fault tree analysis tools yet i...

Fault-tolerant systems designed with redundancy techniques are typically subject to common-cause failures, which are multiple dependent component failures caused by a shared root cause or a common cause (also known as a shock). There are two types of shocks: fatal and non-fatal. A fatal shock (FS) will fail all components of a system. A non-fatal shock (NFS) will affect only a subset of system ...

Résumé L’objet de cette étude est la représentation des Défaillances de Cause Commune (DCC) dans les systèmes programmés de grande taille. Le système considéré est représentatif du contrôle-commande d’une centrale nucléaire. Le modèle retenu de DCC est le modèle d’Atwood. En effet, il permet de représenter les défaillances indépendantes, les défaillances communes non létales pour certains compo...

Abstract: This paper presents reliability and availability analyses of a model representing a system having one robot and n-redundant safety units with common-cause failures. At least k safety units must function successfully for the robot system success. The robot and other failure rates and the partially failed system repair rates are assumed constant and the failed robot-safety system repair...

Imperfect coverage (IPC) occurs when a malicious component failure causes extensive damage due to inadequate fault detection, fault location or fault recovery. Common-cause failures (CCF) are multiple dependent component failures within a system due to a shared root cause. Both imperfect coverage and common-cause failures can exist in distributed computer systems and can contribute significantl...

Standby redundant systems are often adopted in critical applications such as the Emergency Shutdown Systems (ESDS) in Nuclear Power Plants (NPPs). One failure mode of the standby redundant systems is that they are not available when there is a demand. This is a serious safety issue. Another failure mode of the standby safety critical systems is that they function spuriously when there is actual...