Risk evaluations of aging phenomena: The linear aging reliability model and its extensions

Vesely, W.E.; Wolford, A.J.

doi:10.1016/0029-5493(88)90064-7

Cited by 27 publications

(25 citation statements)

References 8 publications

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“…Changes (i.e., degradation) in the failure rate of a component that might be expected to normally occur over the component life are not explicitly represented. However, experience has shown that aging of components generally results in time-dependent failure rates (Vesely and Wolford 1988). In reliability engineering, the failure probability is often defined to be a "bathtub" curve similar to that shown in Figure 3.1 (failure probability expressed as λ(t) in the figure).…”

Section: Erm Methodologymentioning

confidence: 99%

“…In general, PRA models use a static estimate for event probability and POF, typically based on historic observations and engineering judgment. More recently, time-based POF values have been used (Vesely and Wolford 1988;Arjas and Holmberg 1995); however, these are derived from operating experience and traditional reliability analysis and are usually not specific to the operating component.…”

Section: Pra Models and Techniquesmentioning

confidence: 99%

“…Data for component failure rates and failure probabilities comes from generic sources, plant-specific sources, or a combination of the two (as when generic data is adjusted using plant-specific data by performing a Bayesian update). Aging-related failure data, if included, typically utilizes reliability models (Vesely and Wolford 1988;Smith et al 2001). Human error probabilities are generally compiled using human reliability analysis (HRA) that is based on 2.5 research done in NPP control rooms and simulators.…”

Section: Probabilistic Risk Assessmentmentioning

confidence: 99%

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Technical Report on Preliminary Methodology for Enhancing Risk Monitors with Integrated Equipment Condition Assessment

Ramuhalli¹,

Coles²,

Coble³

et al. 2013

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Executive SummaryAdvanced small modular reactors (AdvSMRs) may provide a longer-term alternative to traditional light-water reactors and SMRs based on integral pressurized water reactor concepts currently being considered. AdvSMRs are designed to incorporate multiple modules (which may or may not have shared components and structures) at a single location, comprising a full "plant." AdvSMR operation differs fundamentally from full-size plants because the smaller plants may be used for load-following or peakdemand power generation, instead of baseload generation. AdvSMRs are also being considered for dualuse, where process heat would be used for both electricity generation and another purpose such as hydrogen production or water desalination, shown in Figure Enhancing affordability of AdvSMRs will be critical to ensuring wider deployment. Although some of the loss of economies of scale inherent to AdvSMRs can be recovered, controllable day-to-day costs of AdvSMRs will be dominated by operation and maintenance (O&M) costs.Technologies that help characterize real-time risk are important to controlling O&M costs and improving affordability of AdvSMRs. Given the possibility of frequently changing plant configurations in AdvSMRs, advanced plant configuration information, equipment condition information, and risk monitors are needed to support real-time decisions on O&M. For this purpose, approaches are needed to integrate these three elements in a manner that provides a measure of risk that is customized for each AdvSMR unit, and accounts for the specific operational history of the unit. By integrating technologies for condition assessment with risk monitors, asset optimization and improved economics of AdvSMRs may be enabled by:• Maximizing generation by assessing the potential impact of taking key components offline for testing or maintenance, iv• Supporting reduced O&M staff by aiding in optimization of O&M planning (specifically by assessing the contribution of individual components to changes in risk and using this information for scheduling maintenance activities),• Enabling real-time decisions on stress-relief for risk-significant equipment susceptible to degradation and damage, and• Supporting potential remote siting by providing early warning of potential increases in plant risk.This report describes research results from an initial methodology for such enhanced risk monitors (ERMs) that integrate real-time information about equipment condition and probability of failure (POF) into risk monitors to provide an assessment of dynamic risk as plant equipment ages. This integration occurs at the level of the POF within risk monitors.Risk monitors extend probabilistic risk assessment (PRA) frameworks by incorporating the actual and dynamic plant configuration (e.g., equipment availability, operating regimes, and environmental conditions) into the risk assessment. PRA is itself a systematic safety analysis methodology that follows four steps: identify undesirable consequences (e.g., reactor unavailability, core da...

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Section: Erm Methodologymentioning

confidence: 99%

Section: Pra Models and Techniquesmentioning

confidence: 99%

Section: Probabilistic Risk Assessmentmentioning

confidence: 99%

See 1 more Smart Citation

Technical Report on Preliminary Methodology for Enhancing Risk Monitors with Integrated Equipment Condition Assessment

Ramuhalli¹,

Coles²,

Coble³

et al. 2013

View full text Add to dashboard Cite

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“…Activities connected with the agedependent PSA of NPP include: collected and evaluated data for the age-related degradation of US NPP (Braverman, Hofmayer, Morante, Shteyngart, & Bezler, 2000), modelling ageing of passive systems, structures and components by incorporating a flow accelerated corrosion model into PSA (Smith, Shah, Kao, & Apostolakis, 2001), a procedure for transformation of PSA to age-dependent evaluation (Vesely, 1992), a quantification of the ageing induced risk using PSA and component ageing models (Vesely, Kurth, & Scalzo, 1990;Wolford, Atwood, & Roesener, 1992), a derivation of the linear ageing model and extension to nonlinear and dependent ageing phenomena (Vesely, 1987), ageing-related failure analysis of the nuclear power plant operational data (Levy et al, 1988;Meale & Satterwhite, 1987a) and the impact of the component ageing on the selected support systems reliability and NPP safety (Meale & Satterwhite, 1987b).…”

Section: State-of-the-artmentioning

confidence: 99%

Evaluation of risk and cost using an age-dependent unavailability modelling of test and maintenance for standby components

Kančev

Čepin

2011

Journal of Loss Prevention in the Process Industries

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“…The concept of effective age, also called virtual age, is not new; in fact, several studies in the literature resort to this idea to model the aging of repairable components (e.g. [23][24][25] ). In particular, two approaches, the accelerated life models (ALM) and the proportional hazard models (PHM), have proven to be able to effectively account for the ambient conditions of the component.…”

Section: Failure/degradation Modulementioning

confidence: 99%

A Modeling Framework for Maintenance Optimization of Electrical Components Based on Fuzzy Logic and Effective Age

Baraldi

Balestrero

Compare

et al. 2012

Quality & Reliability Eng

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International audienceIn this article, the problem of building a model in support of maintenance optimization when the only available information is that elicited from one expert is tackled. In particular, the degradation process affecting the component is modeled by resorting to the concept of effective age. Information is elicited from one expert by following a systematic literature approach, and the theoretical framework of fuzzy logic is used to deal with his or her qualitative statements. A hybrid approach based on Monte Carlo method and fuzzy logic is then applied to evaluate the performance of a given maintenance policy. Finally, the proposed methodology is applied to a real case study dealing with a medium-voltage test network

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Risk evaluations of aging phenomena: The linear aging reliability model and its extensions

Cited by 27 publications

References 8 publications

Technical Report on Preliminary Methodology for Enhancing Risk Monitors with Integrated Equipment Condition Assessment

Technical Report on Preliminary Methodology for Enhancing Risk Monitors with Integrated Equipment Condition Assessment

Evaluation of risk and cost using an age-dependent unavailability modelling of test and maintenance for standby components

A Modeling Framework for Maintenance Optimization of Electrical Components Based on Fuzzy Logic and Effective Age

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