Reliability failure methodology

Redesign, detection, and analysis of failure sources serve as verification of redesign effort. Some of the benefits of reliability growth methodology are ... 

The second term in the sum above represents two consequent hinnan failures 1) primary failure of process control 2) secondary failure of taking adequate measure to eliminate the consequences of primary failure. As it has been pointed out in many human reliability analysis methodologies and studies, there is no discussion regarding independency - such actions are dependent to some extent by substance. 

Human error probabilities can also be estimated using methodologies and techniques originally developed in the nuclear industry. A number of different models are available (Swain, Comparative Evaluation of Methods for Human Reliability Analysis, GRS Project RS 688, 1988). This estimation process should be done with great care, as many factors can affect the reliability of the estimates. Methodologies using expert opinion to obtain failure rate and probability estimates have also been used where there is sparse or inappropriate data. 

The failure description is the third part of the taxonomy structure and involves the modes, severities, and types of failures. These are based on models in the In-Plant Reliability Data Base for Nuclear Power Plant Components Data Collection and Methodology Report (IPRDS) and IEEE Std. 500-1984,2 which are discussed in Chapter 2. 

The Reactor Safety Study (WASH-1400) was published by the USNRC in 1975 to set down a methodology for assessing nuclear plant reliability and risk. Of particular Interest to the data analyst are Appendix III, "Failure Data," and Appendix IV, "Common Mode Failures."... 

Similar to reliability work, bad actors are also identified through knowledge of the machinery MTBF by type, unit and service. Resources are likely to be limited, which means we will not be able to investigate all resources that deviate from an acceptable or expected time to failure (TTF). Therefore, the next step is to carefully choose an acceptable TTF for machine breakdown, keeping these limitations in mind. We don t want to start at the top, but it is imperative that we remember to use this process to cover all failures, even if we feel we know all of the bad actors. Later, the importance of this step will become obvious because it will not be as easy for us to tell the bad actors from acceptable actors. Figure 62.3 shows the methodology of this process. 

This section describes a methodical procedure that allows reliability issues to be approached efficiently. MEMS reveal specific reliability aspects, which differ considerably from the reliability issues of integrated circuits and macroscopic devices. A classification of typical MEMS-failure modes is given, as well as an overview of lifetime distribution models. The extraction of reliability parameters is a Tack of failures situation using accelerated aging and suitable models. In a case study, the implementation of the methodology is illustrated with a real-fife example of dynamic mechanical stress on a thin membrane in a hot-film mass-airflow sensor. 

D. Maintainability review This three pronged approach to improving equipment reliability is based on failure analysis to identify root causes, testing of equipment immediately after repair to ensure quality work was performed, and performance analysis of equipment to determine equipment efficiency rates and replacement intervals. This methodology uses predictive technologies. 

Analytical methodology was developed for accurate quantitative analysis of trichothecenes at low part-per-billion levels in blood. Although this methodology was arduous and lacked the ruggedness normally demanded of an analytical procedure which must nave a low failure rates it proved to be both qualitatively reliable and quantitatively accurate when it was combined with a well planned quality assurance program. An indispensable part of developing the quality assurance plan was a formal risk assessment which specifically took into account the possibility of human error. 

The conceptual system selected in step 3 is designed. Reliability and maintainability of this design are assessed. Various methodologies, such as design review, failure mode and effect analysis, fault tree analysis, and probabilistic design approach, can be applied at this step. Reliability is a design parameter and must be incorporated in the system at the design step. 

Costa, E., Sousa, R., Bragan a, S. and Alves, A. C. (2013). An industrial application of the SMED methodology and other Lean production tools. Proceedings of Integrity, Reliability and Failure (1RF2013), INEGI Editions, Funchal/Portugal, 23-27 June 2013. http //hdl.handle. net/1822/25314... 

Optimized preventive maintenance programmes can contribute to ensuring both safe and competitive NPPs. Reliability centered maintenance provides an optimization of preventive maintenance. The principles underlying reliability centred maintenance include preventing failures where the repercussions for the plant could be serious in terms of safety or economics. The methodology involves evaluation of the functional consequences of failure, analyses of experience feedback, and optimization of preventive maintenance tasks. Electricite de France (EdF) has implemented preventive maintenance programmes based on a reliability centred maintenance methodology at EdF nuclear plants, and results have shown benefits in safety, performance and cost. 

Further, it has heen shown that the use of preferential tines (instead of random points) to probe the failure domain of interest makes the effectiveness of the LS methodology almost independent of the failure probability to be estimated this renders LS the most suitable method for an extremely wide range of real-world reliability problems. 

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