Method for assessment of ageing based on PSA results

Volkanovski, Andrija

doi:10.1016/j.nucengdes.2011.06.037

Cited by 12 publications

(9 citation statements)

References 20 publications

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“…Nowadays, different approaches to Ageing PSA are being proposed to account for equipment ageing [12][13][14]. In this respect, lessons learnt on ageing assessment, modelling and management of SSC of NPP in the framework of international programs and initiatives (NPAR, GALL, IGALL, etc.)…”

Section: Probabilistic Safety Assessment and Its Applicationmentioning

confidence: 99%

Ageing PSA incorporating effectiveness of maintenance and testing

Martón¹,

Sánchez²,

Martorell³

2015

Reliability Engineering & System Safety

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This paper proposes a new approach to Ageing Probabilistic Safety Assessment (APSA) modelling, which is intended to be used to support risk-informed decisions on the effectiveness of maintenance management programs and technical specification requirements of critical equipment of Nuclear Power Plants (NPP) within the framework of the Risk Informed Decision Making according to R.G. 1.174 principles. This approach focuses on the incorporation of not only equipment ageing but also effectiveness of maintenance and efficiency of surveillance testing explicitly into APSA models and data. An example of application is presented, which centers on a critical safety-related equipment of a NPP in order to evaluate the risk impact of considering different approaches to APSA and the combined effect of equipment ageing and maintenance and testing alternatives along NPP design life. The risk impact of the several alternatives is quantified and the results shows that such risk depends largely on the model parameters, such as ageing factor, maintenance effectiveness, test efficiency.

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Section: Probabilistic Safety Assessment and Its Applicationmentioning

confidence: 99%

Ageing PSA incorporating effectiveness of maintenance and testing

Martón¹,

Sánchez²,

Martorell³

2015

Reliability Engineering & System Safety

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“…Martón et al [9] propose an approach to modelling the unavailability of safety-related components associated with standby-related failures that explicitly addresses all aspects of the effect of ageing, maintenance effectiveness, and test efficiency. Other authors have proposed alternative approaches to modelling the effect of ageing and test and maintenance activities [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Parameter Estimation of a Reliability Model of Demand‐Caused and Standby‐Related Failures of Safety Components Exposed to Degradation by Demand Stress and Ageing That Undergo Imperfect Maintenance

Martorell

Sánchez

et al. 2017

Mathematical Problems in Engineering

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One can find many reliability, availability, and maintainability (RAM) models proposed in the literature. However, such models become more complex day after day, as there is an attempt to capture equipment performance in a more realistic way, such as, explicitly addressing the effect of component ageing and degradation, surveillance activities, and corrective and preventive maintenance policies. Then, there is a need to fit the best model to real data by estimating the model parameters using an appropriate tool. This problem is not easy to solve in some cases since the number of parameters is large and the available data is scarce. This paper considers two main failure models commonly adopted to represent the probability of failure on demand (PFD) of safety equipment: (1) by demand-caused and (2) standby-related failures. It proposes a maximum likelihood estimation (MLE) approach for parameter estimation of a reliability model of demand-caused and standby-related failures of safety components exposed to degradation by demand stress and ageing that undergo imperfect maintenance. The case study considers real failure, test, and maintenance data for a typical motor-operated valve in a nuclear power plant. The results of the parameters estimation and the adoption of the best model are discussed.

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“…For example, analytical age-dependent unavailability models have been developed adopting linear ageing rates [1], which considers the impact of testing and maintenance activities at least implicitly [2][3][4][5]. Nowadays, one can find several proposals in the literature to integrate such a kind of RAM modelling into the so called Ageing PSA (APSA) [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Optimization of test and maintenance of ageing components consisting of multiple items and addressing effectiveness

Martón

Martorell

Mullor

et al. 2016

Reliability Engineering & System Safety

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There are many models in the literature that have been proposed in the last decades aimed at assessing the reliability, availability and maintainability (RAM) of safety equipment, many of them with a focus on their use to assess the risk level of a technological system or to search for appropriate design and/or surveillance and maintenance policies in order to assure that an optimum level of RAM of safety systems is kept during all the plant operational life. This paper proposes a new approach for RAM modelling that accounts for equipment ageing and maintenance and testing effectiveness of equipment consisting of multiple items in an integrated manner. This model is then used to perform the simultaneous optimization of testing and maintenance for ageing equipment consisting of multiple items. An example of application is provided, which considers a simplified High Pressure Injection System (HPIS) of a typical Power Water Reactor (PWR). Basically, this system consists of motor driven pumps (MDP) and motor operated valves (MOV), where both types of components consists of two items each. These components present different failure and cause modes and behaviours, and they also undertake complex test and maintenance activities depending on the item involved. The results of the example of application demonstrate that the optimization algorithm provide the best solutions when the optimization problem is formulated and solved considering full flexibility in the implementation of testing and maintenance activities taking part of such an integrated RAM model.

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Method for assessment of ageing based on PSA results

Cited by 12 publications

References 20 publications

Ageing PSA incorporating effectiveness of maintenance and testing

Ageing PSA incorporating effectiveness of maintenance and testing

Parameter Estimation of a Reliability Model of Demand‐Caused and Standby‐Related Failures of Safety Components Exposed to Degradation by Demand Stress and Ageing That Undergo Imperfect Maintenance

Optimization of test and maintenance of ageing components consisting of multiple items and addressing effectiveness

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