The methodology to estimate residual parametric common cause failure (CCF) probabilities consists of the selection of the data source, source plants, source systems and component type, failure mode, assessment of the impact vectors, determination of equivalent observations, calculation of CCF rates of different multiplicities with uncertainties using an empirical Bayes estimation method and fin...

A safety instrumented system (SIS) may fail to operate as desired when one or more of its devices fail due to random, systematic, and common cause events. IEC 61511 (ANSI/ISA 84.00.01-2004) stresses the importance of minimizing the propagation of device failure into system failure through design, operating, inspection, and maintenance practices. To fully understand the lifecycle requirements, i...

ABSTRACT This paper Study the reliability and availability characteristics of the system with PM and CCF. The failure times , replacement times, PM times and CCF times of a components are assumed to be exponentially distributed. We derive the mean time to failure( MTTF) and the steady state availability( ) in this system. Some Special cases have been studies theoretically and graphically to obs...

Abstract: This paper presents a mathematical model for a multi-state complex repairable manufacturing system with four types of failures such as common cause, partial, human and catastrophic incorporating waiting time to repair. As regards to repairing of the system, it has to be wait for repair due to unavailability of repair facility after common cause failure. The system may also fail due to...

In this paper we analyze the dynamic behavior of a two unit parallel system with warm standby and common-cause failure. By the semigroup theory of linear operators on the Banach space, we give the wellposedness of the system and then prove the existence of the nonnegative dynamic solution and the steady solution of system. By spectral analysis of the system operator, we show that all the spectr...

In a standard Bayesian approach to the alpha-factor model for common-cause failure, a precise Dirichlet prior distribution models epistemic uncertainty in the alpha-factors. This Dirichlet prior is then updated with observed data to obtain a posterior distribution, which forms the basis for further inferences. In this paper, we adapt the imprecise Dirichlet model of Walley to represent epistemi...

The modeling of dependent failures, specifically Common Cause Failures (CCFs), is one of the most important topics in Probabilistic Risk Analysis (PRA). Currently, CCFs are treated using parametric modeling, which is based on historical failure events. Instead of utilizing the existing data-driven approach, this paper proposes the concept of physics-based CCF modeling, which refers to the incor...

The traditional α-factor model has focused on the occurrence frequencies of common cause failure (CCF) events. Global α-factors in the α-factor model are defined as fractions of failure probability for particular groups of components. However, there are unknown uncertainties in the CCF parameters estimation for the scarcity of available failure data. Joint distributions of CCF parameters are ac...

BACKGROUND It is recognized that FMR1 premutation expansions are associated with premature ovarian failure (POF), but the role of smaller repeats at the boundary of premutation and normal is less clear. METHODS We have therefore investigated the incidence of these intermediate sized FMR1 CGG repeats (35-58 repeats) in a series of 366 women ascertained because of menopause before the age of 40...

In order to develop a Failure Analysis Expert System (FAES), with application for onshore pipeline transporting oil and gas products, the work was split in two parts. Previously failure database and knowledge acquisition method were described in the first part whereas the present, part II, the End-User interface and Algorithm are explained in detail. The proposed Failure Analysis Expert System ...