A condition-based maintenance policy for multi-component systems with a high maintenance setup cost

NARCIS (Netherlands)

Zhu, Q.; Peng, H.; Houtum, van G.J.J.A.N.

2015-01-01

Condition-based maintenance (CBM) is becoming increasingly important due to the development of advanced sensor and information technology, which facilitates the remote collection of condition data. We propose a new CBM policy for multi-component systems with continuous stochastic deteriorations. To

A condition-based maintenance policy for multi-component systems with a high maintenance setup cost

NARCIS (Netherlands)

Zhu, Q.; Peng, H.; Houtum, van G.J.J.A.N.

2012-01-01

Condition-based maintenance (CBM) is becoming increasingly important due to the development of advanced sensor and ICT technology, so that the condition data can be collected remotely. We propose a new CBM policy for multi-component systems with continuous stochastic deteriorations. To reduce the

A novel integrated condition-based maintenance and stochastic flexible job shop scheduling problem

DEFF Research Database (Denmark)

Rahmati, Seyed Habib A.; Ahmadi, Abbas; Govindan, Kannan

2018-01-01

the level of the system optimization. By means of this equipment, managers can benefit from a condition-based maintenance (CBM) for monitoring and managing their system. The chief aim of the paper is to develop a stochastic maintenance problem based on CBM activities engaged with a complex applied......Integrated consideration of production planning and maintenance processes is a real world assumption. Specifically, by improving the monitoring equipment such as various sensors or product-embedded information devices in recent years, joint assessment of these processes is inevitable for enhancing...... production problem called flexible job shop scheduling problem (FJSP). This integrated problem considers two maintenance scenarios in terms of corrective maintenance (CM) and preventive maintenance (PM). The activation of scenario is done by monitoring the degradation condition of the system and comparing...

Cognitive Artificial Intelligence Method for Interpreting Transformer Condition Based on Maintenance Data

Directory of Open Access Journals (Sweden)

Karel Octavianus Bachri

2017-07-01

Full Text Available A3S(Arwin-Adang-Aciek-Sembiring is a method of information fusion at a single observation and OMA3S(Observation Multi-time A3S is a method of information fusion for time-series data. This paper proposes OMA3S-based Cognitive Artificial-Intelligence method for interpreting Transformer Condition, which is calculated based on maintenance data from Indonesia National Electric Company (PLN. First, the proposed method is tested using the previously published data, and then followed by implementation on maintenance data. Maintenance data are fused to obtain part condition, and part conditions are fused to obtain transformer condition. Result shows proposed method is valid for DGA fault identification with the average accuracy of 91.1%. The proposed method not only can interpret the major fault, it can also identify the minor fault occurring along with the major fault, allowing early warning feature. Result also shows part conditions can be interpreted using information fusion on maintenance data, and the transformer condition can be interpreted using information fusion on part conditions. The future works on this research is to gather more data, to elaborate more factors to be fused, and to design a cognitive processor that can be used to implement this concept of intelligent instrumentation.

Analysis of the possibility of applying a condition-based maintenance model on an example of tank weapons

Directory of Open Access Journals (Sweden)

Igor J. Epler

2013-12-01

Full Text Available For any modern army it is very important to continuously maintain a high degree of operational (combat readiness (availability in order to maximize the effectiveness of the use of technical systems. Since determination and prediction of technical states and failures of technical systems in engineering, especially in armament, are difficult due to the impossibility of continuous condition monitoring with appropriate measuring equipment there is a need for a maintenance model that would be most helpful in taking timely action maintenance. In this paper, the subject of research is a model of maintenance of the M-84 tank  weapoons systems.   IntroductionThe M-84 tank is one of the most promising technical systems in the Serbian Army. Its use and modifications are foreseen in the next ten years. The  M-84 is characterized by good tactical and technical characteristics. It has a powerful 125 mm cannon, coupled 7.62 mm machine gun and 12.7 mm anti-aircraft machine gun. The M-84 tank has an automatic battery charger and a fire control system. The fire control system enables fast target tracking and stabilization of the cannon barrel, which is a prerequisite for timely and favorable effect on the target. There are certain ambiguities in the existing model of maintenance of tank weapons.   Technical diagnostics Technical diagnostics, as a part of the process of condition-based maintenance, should determine technical conditions of components or technical systems with certain accuracy at a point in time.   Maintenance strategy A maintenance strategy can be defined as a variant of a maintenance system determined by a concept, organization and character of maintenance procedures, as well as the relationship between the various levels at which maintenance is performed. It is defined for technical system parts, individual technical systems and for system maintenance as a whole. The basic maintenance strategies implemented today are: -      corrective

Heuristic hybrid game approach for fleet condition-based maintenance planning

International Nuclear Information System (INIS)

Feng, Qiang; Bi, Xiong; Zhao, Xiujie; Chen, Yiran; Sun, Bo

2017-01-01

The condition-based maintenance (CBM) method is commonly used to select appropriate maintenance opportunities according to equipment status over a period of time. The CBM of aircraft fleets is a fleet maintenance planning problem. In this problem, mission requirements, resource constraints, and aircraft statuses are considered to find an optimal strategy set. Given that the maintenance strategies for each aircraft are finite, fleet CBM can be treated as a combinatorial optimization problem. In this study, the process of making a decision on the CBM of military fleets is analyzed. The fleet CBM problem is treated as a two-stage dynamic decision-making problem. Aircraft are divided into dispatch and standby sets; thus, the problem scale is significantly reduced. A heuristic hybrid game (HHG) approach comprising a competition game and a cooperative game is proposed on the basis of heuristic rule. In the dispatch set, a competition game approach is proposed to search for a local optimal strategy matrix. A cooperative game method for the two sets is also proposed to ensure global optimization. Finally, a case study regarding a fleet comprising 20 aircraft is conducted, with the results proving that the approach efficiently generates outcomes that meet the mission risk-oriented schedule requirement. - Highlights: • A new heuristic hybrid game method for fleet condition-based maintenance is proposed. • The problem is simplified by hierarchical solving based on dispatch and standby set. • The local optimal solution is got by competition game algorithm for dispatch set. • The global optimal solution is got by cooperative game algorithm between two sets.

Corrosion Sensor Development for Condition-Based Maintenance of Aircraft

Directory of Open Access Journals (Sweden)

Gino Rinaldi

2012-01-01

Full Text Available Aircraft routinely operate in atmospheric environments that, over time, will impact their structural integrity. Material protection and selection schemes notwithstanding, recurrent exposure to chlorides, pollution, temperature gradients, and moisture provide the necessary electrochemical conditions for the development and profusion of corrosion in aircraft structures. For aircraft operators, this becomes an important safety matter as corrosion found in a given aircraft must be assumed to be present in all of that type of aircraft. This safety protocol and its associated unscheduled maintenance requirement drive up the operational costs of the fleet and limit the availability of the aircraft. Hence, there is an opportunity at present for developing novel sensing technologies and schemes to aid in shifting time-based maintenance schedules towards condition-based maintenance procedures. In this work, part of the ongoing development of a multiparameter integrated corrosion sensor is presented. It consists of carbon nanotube/polyaniline polymer sensors and commercial-off-the-shelf sensors. It is being developed primarily for monitoring environmental and material factors for the purpose of providing a means to more accurately assess the structural integrity of aerospace aluminium alloys through fusion of multiparameter sensor data. Preliminary experimental test results are presented for chloride ion concentration, hydrogen gas evolution, humidity variations, and material degradation.

Bayesian based Diagnostic Model for Condition based Maintenance of Offshore Wind Farms

DEFF Research Database (Denmark)

Asgarpour, Masoud; Sørensen, John Dalsgaard

2018-01-01

Operation and maintenance costs are a major contributor to the Levelized Cost of Energy for electricity produced by offshore wind and can be significantly reduced if existing corrective actions are performed as efficiently as possible and if future corrective actions are avoided by performing...... sufficient preventive actions. This paper presents an applied and generic diagnostic model for fault detection and condition based maintenance of offshore wind components. The diagnostic model is based on two probabilistic matrices; first, a confidence matrix, representing the probability of detection using...... for a wind turbine component based on vibration, temperature, and oil particle fault detection methods. The last part of the paper will have a discussion of the case study results and present conclusions....

Knowledge based maintenance

Energy Technology Data Exchange (ETDEWEB)

Sturm, A [Hamburgische Electacitaets-Werke AG Hamburg (Germany)

1998-12-31

The establishment of maintenance strategies is of crucial significance for the reliability of a plant and the economic efficiency of maintenance measures. Knowledge about the condition of components and plants from the technical and business management point of view therefore becomes one of the fundamental questions and the key to efficient management and maintenance. A new way to determine the maintenance strategy can be called: Knowledge Based Maintenance. A simple method for determining strategies while taking the technical condition of the components of the production process into account to the greatest possible degree which can be shown. A software with an algorithm for Knowledge Based Maintenance leads the user during complex work to the determination of maintenance strategies for this complex plant components. (orig.)

Knowledge based maintenance

Energy Technology Data Exchange (ETDEWEB)

Sturm, A. [Hamburgische Electacitaets-Werke AG Hamburg (Germany)

1997-12-31

The establishment of maintenance strategies is of crucial significance for the reliability of a plant and the economic efficiency of maintenance measures. Knowledge about the condition of components and plants from the technical and business management point of view therefore becomes one of the fundamental questions and the key to efficient management and maintenance. A new way to determine the maintenance strategy can be called: Knowledge Based Maintenance. A simple method for determining strategies while taking the technical condition of the components of the production process into account to the greatest possible degree which can be shown. A software with an algorithm for Knowledge Based Maintenance leads the user during complex work to the determination of maintenance strategies for this complex plant components. (orig.)

A Condition Based Maintenance Approach to Forecasting B-1 Aircraft Parts

Science.gov (United States)

2017-03-23

Air Force Institute of Technology AFIT Scholar Theses and Dissertations 3-23-2017 A Condition Based Maintenance Approach to Forecasting B-1 Aircraft...component’s life history where reliability forecasts could be stipulated based on a component’s current condition . One of the major issues their report noted...Engine Condition Monitoring System Specification. Contract Number DOT-CG-80513-A. Grand Prairie, TX. Air Force Materiel Command. (2011) Requirements For

The role of knowledge sharing and transactive memory system on condition based maintenance policy

NARCIS (Netherlands)

Koochaki, J.; Bouwhuis, I. M.

2008-01-01

Today, Condition Based Maintenance (CBM) has reached a sophisticated level in industry and the advantages of predictive maintenance are accepted globally. However, although lots of effort has been put into improving methods and techniques in CBM, most of predictive maintenance programs fail to

Earnings with Condition Based Maintenance; Ganhos com manutencao preditiva baseada em dados de processo em tempo real

Energy Technology Data Exchange (ETDEWEB)

Barabas, Elizabeth [Softbrasil Automacao, Sao Paulo, SP (Brazil)

2008-07-01

Keeping active in perfect functioning is essential for any company. Today, the maintenance has been performed in most of the stops for maintenance. In a modern industrial environment, where the systems provide data and process information in real time, it is possible bring the performance of the plant to a optimized level, through the maintenance based on condition of equipment. This work described the earnings with CBM (Condition Based Maintenance)

An open-source automated continuous condition-based maintenance platform for commercial buildings

Energy Technology Data Exchange (ETDEWEB)

Katipamula, Srinivas; Gowri, Krishnan; Hernandez, George

2016-09-09

This paper describes one such reference process that can be deployed to provide continuous automated conditioned-based maintenance management for buildings that have BIM, a building automation system (BAS) and a computerized maintenance management software (CMMS) systems. The process can be deployed using an open source transactional network platform, VOLTTRON™, designed for distributed sensing and controls and supports both energy efficiency and grid services.

Single-stage Kanban system with deterioration failures and condition-based preventive maintenance

International Nuclear Information System (INIS)

Xanthopoulos, A.S.; Koulouriotis, D.E.; Botsaris, P.N.

2015-01-01

Despite the fact that the fields of pull type production control policies and condition-based preventive maintenance have much in common contextually, they have evolved independently up to now. In this investigation, an attempt is made to bridge the gap between these two branches of knowledge by introducing the single-stage Kanban system with deterioration failures and condition-based preventive maintenance. The formalism of continuous time Markov chains is used to model the system and expressions for eight performance metrics are derived. Two important, from a managerial perspective, constrained optimization problems for the proposed model are defined where the objective is the simultaneous optimization of the Kanban policy, the preventive maintenance policy and the inspection schedule under conflicting performance criteria. Multiple instances of each optimization problem are solved by means of the augmented Lagrangian genetic algorithm. The results from the optimization trials coupled by the results from extensive numerical examples facilitate the thorough investigation of the system’s behaviour. - Highlights: • Kanban system with deterioration failures and preventive maintenance is introduced. • The system is modeled as a continuous time Markov chain. • Expressions for eight performance metrics are derived. • The behavior of the system is studied through numerical examples. • Optimization results for selected performance metrics are presented

Availability analysis of mechanical systems with condition-based maintenance using semi-Markov and evaluation of optimal condition monitoring interval

Science.gov (United States)

Kumar, Girish; Jain, Vipul; Gandhi, O. P.

2018-03-01

Maintenance helps to extend equipment life by improving its condition and avoiding catastrophic failures. Appropriate model or mechanism is, thus, needed to quantify system availability vis-a-vis a given maintenance strategy, which will assist in decision-making for optimal utilization of maintenance resources. This paper deals with semi-Markov process (SMP) modeling for steady state availability analysis of mechanical systems that follow condition-based maintenance (CBM) and evaluation of optimal condition monitoring interval. The developed SMP model is solved using two-stage analytical approach for steady-state availability analysis of the system. Also, CBM interval is decided for maximizing system availability using Genetic Algorithm approach. The main contribution of the paper is in the form of a predictive tool for system availability that will help in deciding the optimum CBM policy. The proposed methodology is demonstrated for a centrifugal pump.

Structural health monitoring methodology for aircraft condition-based maintenance

Science.gov (United States)

Saniger, Jordi; Reithler, Livier; Guedra-Degeorges, Didier; Takeda, Nobuo; Dupuis, Jean Pierre

2001-06-01

Reducing maintenance costs while keeping a constant level of safety is a major issue for Air Forces and airlines. The long term perspective is to implement condition based maintenance to guarantee a constant safety level while decreasing maintenance costs. On this purpose, the development of a generalized Structural Health Monitoring System (SHMS) is needed. The objective of such a system is to localize the damages and to assess their severity, with enough accuracy to allow low cost corrective actions. The present paper describes a SHMS based on acoustic emission technology. This choice was driven by its reliability and wide use in the aerospace industry. The described SHMS uses a new learning methodology which relies on the generation of artificial acoustic emission events on the structure and an acoustic emission sensor network. The calibrated acoustic emission events picked up by the sensors constitute the knowledge set that the system relies on. With this methodology, the anisotropy of composite structures is taken into account, thus avoiding the major cause of errors of classical localization methods. Moreover, it is adaptive to different structures as it does not rely on any particular model but on measured data. The acquired data is processed and the event's location and corrected amplitude are computed. The methodology has been demonstrated and experimental tests on elementary samples presented a degree of accuracy of 1cm.

Prognostics and Condition-Based Maintenance: A New Approach to Precursive Metrics

International Nuclear Information System (INIS)

Jarrell, Donald B.; Sisk, Daniel R.; Bond, Leonard J.

2004-01-01

The assumptions used in the design basis of process equipment have always been as much art as science. The usually imprecise boundaries of the equipments' operational envelope provide opportunities for two major improvements in the operations and maintenance (O and M) of process machinery: (a) the actual versus intended machine environment can be understood and brought into much better alignment and (b) the end goal can define O and M strategies in terms of life cycle and economic management of plant assets.Scientists at the Pacific Northwest National Laboratory (PNNL) have performed experiments aimed at understanding and controlling aging of both safety-specific nuclear plant components and the infrastructure that supports essential plant processes. In this paper we examine the development of aging precursor metrics and their correlation with degradation rate and projected machinery failure.Degradation-specific correlations have been developed at PNNL that will allow accurate physics-based diagnostic and prognostic determinations to be derived from a new view of condition-based maintenance. This view, founded in root cause analysis, is focused on quantifying the primary stressor(s) responsible for degradation in the component of interest and formulating a deterministic relationship between the stressor intensity and the resulting degradation rate. This precursive relationship between the performance, degradation, and underlying stressor set is used to gain a first-principles approach to prognostic determinations. A holistic infrastructure approach, as applied through a conditions-based maintenance framework, will allow intelligent, automated diagnostic and prognostic programming to provide O and M practitioners with an understanding of the condition of their machinery today and an assurance of its operational state tomorrow

Condition Based Maintenance of Space Exploration Vehicles Using Structural Health Monitoring, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Acellent Technologies proposes to develop an autonomous and automated diagnostic system for condition based maintenance (CBM) of safety critical structures for space...

Present state of condition based maintenance (CBM) and its future problem

International Nuclear Information System (INIS)

Hashimoto, Satoshi; Nogami, Takeki; Sugiyama, Naoki

2008-01-01

New inspection system of the nuclear power plant will be introduced from 2008. In this feature, eleven experts from electric utilities, venders and academia described their views or activities about Condition Based Maintenance (CBM) with a new inspection system attracting attention. These are titled as 'Electric utilities view on CBM and its technology', Deployment results of developed CBM technologies', 'Valve diagnostic analysis support system with wireless technology applied', 'Portable vibration checker', 'Tribology diagnosis with no overhaul', 'Infrared thermograph diagnosis', 'Pipewall thinning inspection and management' and, in addition, the US trend and also the development trend of the CBM advancement technology in the vender and university. CBM technology will be introduced step-by-step and contribute to establish reliability based maintenance. (T. Tanaka)

A model for determining condition-based maintenance policies for deteriorating multi-component systems

NARCIS (Netherlands)

Hontelez, J.A.M.; Wijnmalen, D.J.D.

1993-01-01

We discuss a method to determine strategies for preventive maintenance of systems consisting of gradually deteriorating components. A model has been developed to compute not only the range of conditions inducing a repair action, but also inspection moments based on the last known condition value so

The business case for condition-based maintenance: a hybrid (non-) financial approach

NARCIS (Netherlands)

Tiddens, W.W.; Tinga, T.; Braaksma, A.J.J.; Brouwer, O.; Cepin, Marko; Bris, Radim

2017-01-01

Although developing business cases is key for evaluating project success, the costs and benefits of condition-based maintenance (CBM) implementations are often not explicitly defined and evaluated. Using the design science methodology, we developed a hybrid business case approach to help managers

A condition-based maintenance policy for multi-component systems with Lévy copulas dependence

International Nuclear Information System (INIS)

Li, Heping; Deloux, Estelle; Dieulle, Laurence

2016-01-01

In this paper, we propose a new condition-based maintenance policy for multi-component systems taking into account stochastic and economic dependences. The stochastic dependence between components due to common environment is modelled by Lévy copulas. Its influence on the maintenance optimization is investigated with different dependence degrees. On the issue of economic dependence providing opportunities to group maintenance activities, a new maintenance decision rule is proposed which permits maintenance grouping. In order to evaluate the performance of the proposed maintenance policy, we compare it to the classical maintenance policies. - Highlights: • A new adaptive maintenance policy for grouping maintenance actions is proposed. • The impacts of both economic and stochastic dependences are investigated. • The performance of the proposed maintenance policy is evaluated under different system configurations. • The stochastic dependence is modelled by Lévy copulas. • The proposed maintenance decision rule can take full advantage of economic and stochastic dependences.

Bayesian Based Diagnostic Model for Condition Based Maintenance of Offshore Wind Farms

Directory of Open Access Journals (Sweden)

Masoud Asgarpour

2018-01-01

Full Text Available Operation and maintenance costs are a major contributor to the Levelized Cost of Energy for electricity produced by offshore wind and can be significantly reduced if existing corrective actions are performed as efficiently as possible and if future corrective actions are avoided by performing sufficient preventive actions. This paper presents an applied and generic diagnostic model for fault detection and condition based maintenance of offshore wind components. The diagnostic model is based on two probabilistic matrices; first, a confidence matrix, representing the probability of detection using each fault detection method, and second, a diagnosis matrix, representing the individual outcome of each fault detection method. Once the confidence and diagnosis matrices of a component are defined, the individual diagnoses of each fault detection method are combined into a final verdict on the fault state of that component. Furthermore, this paper introduces a Bayesian updating model based on observations collected by inspections to decrease the uncertainty of initial confidence matrix. The framework and implementation of the presented diagnostic model are further explained within a case study for a wind turbine component based on vibration, temperature, and oil particle fault detection methods. The last part of the paper will have a discussion of the case study results and present conclusions.

Basic Concept and Theoretical Study of Condition-based Maintenance for Power Transmission System

Institute of Scientific and Technical Information of China (English)

LIMing; HAN Xueshan; YANG Ming; GUO Zhihong

2011-01-01

The appropriate maintenance time for the single equipment can be found easily and efficiently under the background of condition-based maintenance. However, from the perspective of the whole power system, discrepancy between equipment individual and the whole power system would appear. Once this discrepancy can not be coordinated, it will certainly cause contradiction and conflict between individual equipment and the whole system, and lose the integral efficiency. To solve this contradiction and conflicts is of significant meaning.

An Optimization Method for Condition Based Maintenance of Aircraft Fleet Considering Prognostics Uncertainty

Directory of Open Access Journals (Sweden)

Qiang Feng

2014-01-01

Full Text Available An optimization method for condition based maintenance (CBM of aircraft fleet considering prognostics uncertainty is proposed. The CBM and dispatch process of aircraft fleet is analyzed first, and the alternative strategy sets for single aircraft are given. Then, the optimization problem of fleet CBM with lower maintenance cost and dispatch risk is translated to the combinatorial optimization problem of single aircraft strategy. Remain useful life (RUL distribution of the key line replaceable Module (LRM has been transformed into the failure probability of the aircraft and the fleet health status matrix is established. And the calculation method of the costs and risks for mission based on health status matrix and maintenance matrix is given. Further, an optimization method for fleet dispatch and CBM under acceptable risk is proposed based on an improved genetic algorithm. Finally, a fleet of 10 aircrafts is studied to verify the proposed method. The results shows that it could realize optimization and control of the aircraft fleet oriented to mission success.

Improvement of condition-based maintenance technology by utilization of thermography

International Nuclear Information System (INIS)

Shimada, Hiroki

2004-01-01

In the United States, condition-based maintenance technology comprising IR thermography (hereafter ''thermography'' for short) has been regarded in recent years as the established means for effectively improvement the performance of accident-preventive measures for nuclear power stations. As very few nuclear power plants in Japan have been utilizing the technology, measures for allowing power station personnel to use the technology with ease have been studied on an empirical basis. First, in view of improving the measuring efficiency to determine temperatures more accurately with a single measurement, principal factors affecting the measured temperature values have been analyzed. As a result, it has been found effective for accurate temperature measurement to make use of the table to radiation rates that have been determined for each facility coating specification by using a black body tape and to determine the measuring spot by avoiding rear heat sources (influence of reflection ratio) and background noise (influence of scattered light). Concurrently, as a result of determining the IR attenuation in the atmosphere, thermographic measurement has been found feasible without any significant attenuation as long as the distance is below 10 meters. Further, every power station facility (mainly electrical facilities) that is immune to thermography has been identified. These study results have been documented in the form of the ''Thermography Measurement Manual'' by also including in it the descriptions on abnormal thermal images and the judgment criteria at elevated temperatures that have been used in the United States. Based on these accomplishments, condition-based maintenance technology employing thermography has been applied to on-site investigation of nuclear power stations, and the effectiveness of thermography-aided accident-prevention has been demonstrated by detecting locally temperature rising spots of power cable joints. Moreover, with respect to maintenance

Development and Implementation of a Condition Based Maintenance Program for Geothermal Power Plants; FINAL

International Nuclear Information System (INIS)

Steve Miller; Jim Eddy; Murray Grande; Shawn Bratt; Manuchehr Shirmohamadi

2002-01-01

This report describes the development of the RCM team, identifying plant assets and developing an asset hierarchy, the development of sample Failure Mode Effects Analysis (FMEAs), identifying and prioritizing plant systems and components for RCM analysis, and identifying RCM/CBM software/hardware vendors. It also includes the Failure Mode Effects Analysis (FMEA) for all Class I Systems, Maintenance Task Assignments, use of Conditioned Based Maintenance (CBM) Tools and Displays of the RCM software System Development to date

Condition based monitoring, diagnosis and maintenance on operating equipments of a hydraulic generator unit

International Nuclear Information System (INIS)

Liu, X T; Feng, F Z; Si, A W

2012-01-01

According to performance characteristics of operating equipments in a hydraulic generator unit (HGU), the relative techniques on condition monitoring and fault diagnosis (CMFD) are introduced in this paper, especially the key technologies are emphasized, such as equipment monitoring, expert system (ES), intelligent diagnosis and condition based maintenance (CBM). Meanwhile, according to the instructor on CBM proposed by State electric power corporation, based on integrated mode, the main steps on implementation of CBM are discussed in this paper.

Ageing Management Based Maintenance at ETRR-II

Energy Technology Data Exchange (ETDEWEB)

Kamoon, A.; Ali, A., E-mail: akamoun2004@yahoo.com [Inshas Nuclear Research Centre, Egyptian Atomic Energy Authority (EAEA), Cairo (Egypt)

2014-08-15

The second research reactor of Egypt, ETRR-II, is an open pool type multi-purpose reactor of 22 MW that has been in operation since 1998. The main purposes of ETRR-II are the production of radioisotopes, personnel training, research and development. Ageing management of ETRR-II is based on the maintenance programme. This programme was planned to have a proactive maintenance strategy that mainly depends on adequate preventive and predictive maintenance. Screening of SSCs is based on safety classes, needs and quality levels. The operation condition and maintenance history are the basis to assess the level of degradation. The ultimate aim of the maintenance team is to perform adequate maintenance work only when it is really necessary. The objectives of the ageing management based maintenance are to maintain and improve equipment availability, confirm compliance with operational limits and conditions, and detect and correct any abnormal condition that might affect reactor safety. The programme also helps to detect trends in ageing so that a plan for mitigating ageing effects can be prepared and implemented. Reactor service conditions are monitored through many parameters and conditions such as conductivity and pH of coolant water, water radiochemical analysis, thermal and hydraulic parameters, a leak detection system, corrosion rate of piping, vibration level of rotating equipment and control rod drop time.

Knowledge lost in data : Organizational impediments to condition-based maintenance in the process industry

NARCIS (Netherlands)

van de Kerkhof, Roland; Akkermans, Henk; Noorderhaven, Niels; Zijm, H.; Klumpp, M.; Clausen, U.; Ten Hompel, M.

2016-01-01

In this chapter we report on a pilot study of Condition-Based Maintenance (CBM) in the process industries, such as the steelmaking- and chemical industries, and propose a diagnostic instrument for systematically analysing the challenges to the successful implementation and execution of a CBM

Data mining and statistical process control for condition-based maintenance; Datamining und statistische Prozesskontrolle zur zustandsorientierten Instandhaltung

Energy Technology Data Exchange (ETDEWEB)

Deeskow, Peter; Steinmetz, Urs; Hay, Martin [Evonik Energy Services, Essen (Germany)

2008-07-01

Optimum, condition-based maintenance should balance the commercial consequences of an efficiency loss or a component failure and the cost of maintenance. This requires an early and highly reliable detection of abnormalities of the component/unit behaviour. For this purpose key performance indicators (KPIs) can be used which are online calculated from operational measurements and which solely depend on the component condition and do not depend on other influencing factors such as operation mode, load or ambient conditions. Software tools using data mining methods can facilitate the definition and calculation of such KPIs. (orig.)

Advanced maintenance strategies for power plant operators - introducing inter-plant life cycle management. ZES research focus 'condition-based maintenance in power engineering'

International Nuclear Information System (INIS)

Graeber, U.

2003-01-01

The optimisation of maintenance activities observed in recent years can be attributed above all to the use and continuing development of testing and diagnostic techniques, to the increased level of system and component automation and to more efficient work organisation. Despite the considerable success of these efforts, the potential for further cost reductions is still far from exhausted. The risks connected to reliability, availability and safety need to be analysed in greater detail in order to ensure the sustainability of the savings already achieved as well as those yet to be realised. The systematic application of condition-based maintenance and the introduction of structured life cycle management are essential prerequisites. Within the framework of its ''Condition-Based Maintenance in Power Engineering'' research focus, the Energy Research Centre (ZES) has set up a specialist network in which experts from various institutes belonging to the Faculty of Mechanical Engineering and the Faculty of Informatic, Electrical Engineering and Information Technology can develop interdisciplinary solutions for advanced maintenance strategies. The ZES offers the industry a platform for cooperating on current issues relating to the supply of energy and supports the movement towards sustainable improvements to competitiveness through research and consulting activities. It applies professional project and quality management procedures to ensure that contracts covering interdisciplinary topics and projects are handled in a coherent manner. (orig.)

Case Based Asset Maintenance for the Electric Equipment

International Nuclear Information System (INIS)

Kim, Ji-Hyeon; Jung, Jae-Cheon; Chang, Young-Woo; Chang, Hoon-Seon; Kim, Jae-Cheol; Kim, Hang-Bae; Kim, Kyu-Ho; Hur, Yong; Lee, Dong-Chul

2006-01-01

The electric equipment maintenance strategies are changing from PM(Preventive Maintenance) or CM(Corrective Maintenance) to CBM(Condition Based Maintenance). The main benefits of CBM are reduced possibility of service failures of critical equipment and reduced costs or maintenance work. In CBM, the equipment status need to be monitored continuously and a decision should be made whether an equipment need to be repaired or replaced. For the maintenance decision making, the CBR(Case Base Reasoning) system is introduced. The CBR system receives the current equipment status and retrieves the case based historic database to determine any possible equipment failure under current conditions. In retrieving the case based historic data, the suggested DSS(Decision Support System) uses a reasoning engine with an equipment/asset ontology that describes the equipment subsumption relationships

The use of condition monitoring information for maintenance planning and decision-making

Energy Technology Data Exchange (ETDEWEB)

Laakso, K.; Rosqvist, T. [VTT Industrial Systems (Finland); Paulsen, J.L. [Risoe National Lab., Roskilde (Denmark)

2002-12-01

A survey is presented outlining the use of condition monitoring information in three Nordic nuclear power plants. The questions of the survey relate to the role of condition monitoring in strategic, as well as operative, maintenance planning and decision-making. The survey indicates that condition monitoring is increasingly implemented at nuclear power plants, but very selectively and in a rather slow pace for predictive maintenance. A combined strategy of condition based maintenance and predetermined preventive maintenance is applied for important equipment such as main circulation pumps and steam turbines. A realistic aim is to reduce the number of costly or error prone maintenance and disassembling inspection activities by condition monitoring given that the approach enables a good diagnosis and prediction. Systematic follow-up and analysis of such condition monitoring information followed by a case-specific planning and decision making of timely and rightly directed maintenance actions can justify an extension of the intervals of a number of predetermined inspection, maintenance or periodic testing tasks. (au)

Machine and lubricant condition monitoring for extended equipment lifetimes and predictive maintenance

Energy Technology Data Exchange (ETDEWEB)

Lukas, M; Anderson, D P [Spectro Incorporated, Littleton, Massachusetts (United States)

1998-12-31

Predictive maintenance has gained wide acceptance as a cost cutting strategy in modern industry. Condition monitoring by lubricant analysis is one of the basic tools of a predictive maintenance program along with vibration monitoring, performance monitoring and thermography. In today`s modern power generation, manufacturing, refinery, transportation, mining, and military operations, the cost of equipment maintenance, service, and lubricants are ever increasing. Parts, labor, equipment downtime and lubricant prices and disposal costs are a primary concern in a well run maintenance management program. Machine condition monitoring based on oil analysis has become a prerequisite in most maintenance programs. Few operations can afford not to implement a program if they wish to remain competitive, and in some cases, profitable. This presentation describes a comprehensive Machine Condition Monitoring Program based on oil analysis. Actual operational condition monitoring programs will be used to review basic components and analytical requirements. Case histories will be cited as examples of cost savings, reduced equipment downtime and increased efficiencies of maintenance programs through a well managed oil analysis program. (orig.)

Machine and lubricant condition monitoring for extended equipment lifetimes and predictive maintenance

Energy Technology Data Exchange (ETDEWEB)

Lukas, M.; Anderson, D.P. [Spectro Incorporated, Littleton, Massachusetts (United States)

1997-12-31

Predictive maintenance has gained wide acceptance as a cost cutting strategy in modern industry. Condition monitoring by lubricant analysis is one of the basic tools of a predictive maintenance program along with vibration monitoring, performance monitoring and thermography. In today`s modern power generation, manufacturing, refinery, transportation, mining, and military operations, the cost of equipment maintenance, service, and lubricants are ever increasing. Parts, labor, equipment downtime and lubricant prices and disposal costs are a primary concern in a well run maintenance management program. Machine condition monitoring based on oil analysis has become a prerequisite in most maintenance programs. Few operations can afford not to implement a program if they wish to remain competitive, and in some cases, profitable. This presentation describes a comprehensive Machine Condition Monitoring Program based on oil analysis. Actual operational condition monitoring programs will be used to review basic components and analytical requirements. Case histories will be cited as examples of cost savings, reduced equipment downtime and increased efficiencies of maintenance programs through a well managed oil analysis program. (orig.)

Quantified Risk Ranking Model for Condition-Based Risk and Reliability Centered Maintenance

Science.gov (United States)

Chattopadhyaya, Pradip Kumar; Basu, Sushil Kumar; Majumdar, Manik Chandra

2017-06-01

In the recent past, risk and reliability centered maintenance (RRCM) framework is introduced with a shift in the methodological focus from reliability and probabilities (expected values) to reliability, uncertainty and risk. In this paper authors explain a novel methodology for risk quantification and ranking the critical items for prioritizing the maintenance actions on the basis of condition-based risk and reliability centered maintenance (CBRRCM). The critical items are identified through criticality analysis of RPN values of items of a system and the maintenance significant precipitating factors (MSPF) of items are evaluated. The criticality of risk is assessed using three risk coefficients. The likelihood risk coefficient treats the probability as a fuzzy number. The abstract risk coefficient deduces risk influenced by uncertainty, sensitivity besides other factors. The third risk coefficient is called hazardous risk coefficient, which is due to anticipated hazards which may occur in the future and the risk is deduced from criteria of consequences on safety, environment, maintenance and economic risks with corresponding cost for consequences. The characteristic values of all the three risk coefficients are obtained with a particular test. With few more tests on the system, the values may change significantly within controlling range of each coefficient, hence `random number simulation' is resorted to obtain one distinctive value for each coefficient. The risk coefficients are statistically added to obtain final risk coefficient of each critical item and then the final rankings of critical items are estimated. The prioritization in ranking of critical items using the developed mathematical model for risk assessment shall be useful in optimization of financial losses and timing of maintenance actions.

The dynamic pressure measurements of the nuclear reactor coolant for condition-based maintenance of the reactor

International Nuclear Information System (INIS)

Es-Saheb, M.H.H.

1990-01-01

The condition-based maintenance of the nuclear reactor, by monitoring and measuring the instantaneous dynamic pressure distribution of the coolant (water) impact on the solid surfaces of the reactor during operation is presented. The behaviour of water domes (jets) produced by underwater explosions of small changes of P.E.T.N. at various depths in two different size cylindrical containers, which simulate the nuclear reactor, is investigated. Water surface domes (jets) from the underwater explosions are photographed. Depending on the depth of the charge, curved and flat top jets of up to 455 mm diameter and impact speeds of up to 70 m/sec. are observed. The instabilities in the dome surfaces are observed and the instantaneous profiles are analysed. It is found that, in all cases tested, the maximum pressure takes place at the center of the jet and could reach up to 3.0 times the on-dimensional impact pressure value. The use of their measurements, as online monitoring for condition-based maintenance and design-out maintenance is discussed. 18 refs

Condition-based maintenance. With application on a heat exchanger and a pump; Tillstaandsbaserat underhaall. Med applikation paa en vaermevaexlare och en pump

Energy Technology Data Exchange (ETDEWEB)

Raaberg, Martin; Slaetteke, Ola

2012-02-15

Regular maintenance is required to extend the life of a plant's components and maintain optimum operation. Unnecessary outages from maintenance may inflict large monetary losses. Therefore, a cost-effective maintenance system should be condition-based rather than time-based. The optimal maintenance scheme requires a process model and a forecast of the operation conditions of this model. At least one of the model parameters should be affected by the maintenance. To determine the actual status of the plant, the model parameters should be estimated. This requires an analysis of available data to detect degradation of the critical components performance. Base load plants usually operate at maximum production or as close to maximum as possible at stabile conditions during long periods. Since the operating time is long and usually at high load in base load plants, advanced control systems and maintenance planning is most profitable in such plants. Advanced control and process optimization requires dynamic process models. Due to the long operating time of a base load plant, it is natural that its process characteristics change, such as wear and fouling. This means that models must be adapted continuously in order to generate a good approximation and thus a good basis for control and optimization. The problem is that the stable operation condition of a base load plant prevents a good estimate of model parameters through the lack of excitation of the process

Condition-based maintenance effectiveness for series–parallel power generation system—A combined Markovian simulation model

International Nuclear Information System (INIS)

Azadeh, A.; Asadzadeh, S.M.; Salehi, N.; Firoozi, M.

2015-01-01

Condition-based maintenance (CBM) is an increasingly applicable policy in the competitive marketplace as a means of improving equipment reliability and efficiency. Not only has maintenance a close relationship with safety but its costs also make it even more attractive issue for researchers. This study proposes a model to evaluate the effectiveness of CBM policy compared to two other maintenance policies: Corrective Maintenance (CM) and Preventive Maintenance (PM). Maintenance policies are compared through two system performance indicators: reliability and cost. To estimate the reliability and costs of the system, the proposed Markovian discrete-event simulation model is developed under each of these policies. The applicability and usefulness of the proposed Markovian simulation model is illustrated for a series–parallel power generation system. The simulated characteristics of CBM system include its prognostics efficiency to estimate remaining useful life of the equipment. Results show that with an efficient prognostics, CBM policy is an effective strategy compared to other maintenance strategies. - Highlights: • A model is developed to evaluate the effectiveness of CBM policy. • Maintenance policies are compared through reliability and cost. • A Markovian simulation model is developed. • A series–parallel power generation system is considered. • CBM is an effective strategy compared to others

A condition-based maintenance policy with non-periodic inspections for a two-unit series system

International Nuclear Information System (INIS)

Castanier, B.; Grall, A.; Berenguer, C.

2005-01-01

This paper considers a condition-based maintenance policy for a two-unit deteriorating system. Each unit is subject to gradual deterioration and is monitored by sequential non-periodic inspections. It can be maintained by good as new preventive or corrective replacements. Every inspection or replacement entails a set-up cost and a component-specific unit cost but if actions on the two components are combined, the set-up cost is charged only once. A parametric maintenance decision framework is proposed to coordinate inspection/replacement of the two components and minimize the long-run maintenance cost of the system. A stochastic model is developed on the basis of the semi-regenerative properties of the maintained system state and the associated cost model is used to assess and optimize the performance of the maintenance model. Numerical experiments emphasize the interest of a control of the operation groupings

Application of T2 Control Charts and Hidden Markov Models in Condition-Based Maintenance at Thermoelectric Power Plants

Directory of Open Access Journals (Sweden)

Emilija Kisić

2015-01-01

Full Text Available An innovative approach to condition-based maintenance of coal grinding subsystems at thermoelectric power plants is proposed in the paper. Coal mill grinding tables become worn over time and need to be replaced through time-based maintenance, after a certain number of service hours. At times such replacement is necessary earlier or later than prescribed, depending on the quality of the coal and of the grinding table itself. Considerable financial losses are incurred when the entire coal grinding subsystem is shut down and the grinding table found to not actually require replacement. The only way to determine whether replacement is necessary is to shut down and open the entire subsystem for visual inspection. The proposed algorithm supports condition-based maintenance and involves the application of T2 control charts to distinct acoustic signal parameters in the frequency domain and the construction of Hidden Markov Models whose observations are coded samples from the control charts. In the present research, the acoustic signals were collected by coal mill monitoring at the thermoelectric power plant “Kostolac” in Serbia. The proposed approach provides information about the current condition of the grinding table.

Improvement of railway ballast maintenance approach, incorporating ballast geometry and fouling conditions

Science.gov (United States)

Sadeghi, J.; Motieyan-Najar, M. E.; Zakeri, J. A.; Yousefi, B.; Mollazadeh, M.

2018-04-01

Ballast plays an important role in the stability of railway track systems. The effectiveness of the ballast in maintaining the track stability is very much dependent on its mechanical conditions. The available ballast maintenance approaches are mainly based on only track geometry conditions (such as track profile) which do not sufficiently reflect the ballast mechanical behaviors. That is, the ballast potential of degradation (i.e., ballast long term behaviors) has been omitted. This makes the effectiveness of the current ballast maintenance approach questionable, indicating a need for a more comprehensive and effective ballast conditions assessment technique. In response to this need, two ballast condition indices based on ballast geometry degradation (BGI) and the level of ballast fouling (BFI) as the main indicators of ballast mechanical behavior were developed. The BGI is a function of the standard deviations of track alignment, unevenness and twist. The BFI was developed based on the data obtained from the ground penetration radar (GPR). Making use of the new indices, a more reliable maintenance algorithm was developed. Through illustrations of the applicability of the new maintenance algorithm in a railway line, it was shown that the new algorithm causes a considerable improvement in the maintenance effectiveness and an increase in the life cycle of railway tracks by making more effective allocation of resources and more accurate maintenance planning.

An improved segmentation-based HMM learning method for Condition-based Maintenance

International Nuclear Information System (INIS)

Liu, T; Lemeire, J; Cartella, F; Meganck, S

2012-01-01

In the domain of condition-based maintenance (CBM), persistence of machine states is a valid assumption. Based on this assumption, we present an improved Hidden Markov Model (HMM) learning algorithm for the assessment of equipment states. By a good estimation of initial parameters, more accurate learning can be achieved than by regular HMM learning methods which start with randomly chosen initial parameters. It is also better in avoiding getting trapped in local maxima. The data is segmented with a change-point analysis method which uses a combination of cumulative sum charts (CUSUM) and bootstrapping techniques. The method determines a confidence level that a state change happens. After the data is segmented, in order to label and combine the segments corresponding to the same states, a clustering technique is used based on a low-pass filter or root mean square (RMS) values of the features. The segments with their labelled hidden state are taken as 'evidence' to estimate the parameters of an HMM. Then, the estimated parameters are served as initial parameters for the traditional Baum-Welch (BW) learning algorithms, which are used to improve the parameters and train the model. Experiments on simulated and real data demonstrate that both performance and convergence speed is improved.

Advanced maintenance strategies for power plant operators - introducing inter-plant life cycle management. ZES research focus 'condition-based maintenance in power engineering'

Energy Technology Data Exchange (ETDEWEB)

Graeber, U.

2003-07-01

The optimisation of maintenance activities observed in recent years can be attributed above all to the use and continuing development of testing and diagnostic techniques, to the increased level of system and component automation and to more efficient work organisation. Despite the considerable success of these efforts, the potential for further cost reductions is still far from exhausted. The risks connected to reliability, availability and safety need to be analysed in greater detail in order to ensure the sustainability of the savings already achieved as well as those yet to be realised. The systematic application of condition-based maintenance and the introduction of structured life cycle management are essential prerequisites. Within the framework of its ''Condition-Based Maintenance in Power Engineering'' research focus, the Energy Research Centre (ZES) has set up a specialist network in which experts from various institutes belonging to the Faculty of Mechanical Engineering and the Faculty of Informatic, Electrical Engineering and Information Technology can develop interdisciplinary solutions for advanced maintenance strategies. The ZES offers the industry a platform for cooperating on current issues relating to the supply of energy and supports the movement towards sustainable improvements to competitiveness through research and consulting activities. It applies professional project and quality management procedures to ensure that contracts covering interdisciplinary topics and projects are handled in a coherent manner. (orig.)

A condition-based maintenance of a dependent degradation-threshold-shock model in a system with multiple degradation processes

International Nuclear Information System (INIS)

Caballé, N.C.; Castro, I.T.; Pérez, C.J.; Lanza-Gutiérrez, J.M.

2015-01-01

This paper proposes a condition-based maintenance strategy for a system subject to two dependent causes of failure: degradation and sudden shocks. The internal degradation is reflected by the presence of multiple degradation processes in the system. Degradation processes start at random times following a Non-homogeneous Poisson process and their growths are modelled by using a gamma process. When the deterioration level of a degradation process exceeds a predetermined value, we assume that a degradation failure occurs. Furthermore, the system is subject to sudden shocks that arrive at the system following a Doubly Stochastic Poisson Process. A sudden shock provokes the total breakdown of the system. Thus, the state of the system is evaluated at inspection times and different maintenance tasks can be carried out. If the system is still working at an inspection time, a preventive maintenance task is performed if the deterioration level of a degradation process exceeds a certain threshold. A corrective maintenance task is performed if the system is down at an inspection time. A preventive (corrective) maintenance task implies the replacement of the system by a new one. Under this maintenance strategy, the expected cost rate function is obtained. A numerical example illustrates the analytical results. - Highlights: • A condition-based maintenance model is proposed. • Two dependent causes of failure are considered: deterioration and external shocks. • Deterioration is given by multiple degradation processes growing by a gamma process. • The initiation of degradation processes follows a Non-homogeneous Poisson process. • External shocks arrive at the system by using a Doubly Stochastic Poisson Process

Prognostics and Condition Based Maintenance: A New Approach to Precursive Metrics

International Nuclear Information System (INIS)

Jarrell, Donald B.; Sisk, Daniel R.; Bond, Leonard J.

2002-01-01

Scientists at the Pacific Northwest National Laboratory (PNNL) have examined the necessity for understanding and controlling the aging process of both safety-specific plant components and the infrastructure that supports these processes. In this paper we examine the preliminary development of aging precursor metrics and their correlation with degradation rate and projected machine failure. Degradation specific correlations are currently being developed at PNNL that will allow accurate physics-based diagnostic and prognostic determinations to be derived from a new view of condition based maintenance. This view, founded in root cause analysis, is focused on quantifying the primary stressor(s) responsible for degradation in the component of interest. The derivative relationship between the performance, degradation and the underlying stressor set is used to gain a first principles approach to prognostic determinations. The assumptions used for the design basis of process equipment have always been as much art as science and for this reason have been misused or relegated into obscurity in all but the nuclear industry. The ability to successfully link degradation and expected equipment life to stressor intensity level is valuable in that it quantifies the degree of machine stress for a given production level. This allows two major improvements in the O and M of process machinery: (1) the actual versus intended machine environment can be understood and brought into much better alignment, and (2) the end goal can define operations and maintenance strategies in terms of life cycle and economic management of plant assets. A holistic infrastructure approach, as applied through a CBM framework, will allow intelligent, automated diagnostic and prognostic programs to provide O and M practitioners with an understanding of the condition of their machinery today and an assurance of its operational state tomorrow

Context-Dependent Prognostics and Health Assessment: A Condition-Based Maintenance Approach That Supports Mission Compliance

Energy Technology Data Exchange (ETDEWEB)

Allgood, G.O.; Kercel, S.W.

1999-04-19

In today's manufacturing environment, plants, systems, and equipment are being asked to perform at levels not thought possible a decade ago. The intent is to improve process operations and equipment reliability, availability, and maintainability without costly upgrades. Of course these gains must be achieved without impacting operational performance. Downsizing is also taking its toll on operations. Loss of personnel, particularly those who represent the corporate history, is depleting US industries of their valuable experiential base which has been relied on so heavily in the past. These realizations are causing companies to rethink their condition-based maintenance policies by moving away from reacting to equipment problems to taking a proactive approach by anticipating needs based on market and customer requirements. This paper describes a different approach to condition-based maintenance-context-dependent prognostics and health assessment. This diagnostic capability is developed around a context-dependent model that provides a capability to anticipate impending failures and determine machine performance over a protracted period of time. This prognostic capability links operational requirements to an economic performance model. In this context, a system may provide 100% operability with less than 100% functionality. This paradigm is used to facilitate optimal logistic supply and support.

Maintenance Decision Making based on different types of data fusion

OpenAIRE

Galar, D.; Gustafson, A.; Tormos Martínez, Bernardo Vicente; Berges, Luis

2012-01-01

[EN] Over the last decade, system integration is applied more as it allows organizations to streamline business processes. A recent development in the asset engineering management is to leverage the investment already made in process control systems. This allows the operations, maintenance, and process control teams to monitor and determine new alarm level based on the physical condition data of the critical machines. Condition-based maintenance (CBM) is a maintenance philosophy base...

Operation and maintenance requirements of system design bases

International Nuclear Information System (INIS)

Banerjee, A.K.; Hanley, N.E.

1989-01-01

All system designs make assumptions about system operation testing, inspection, and maintenance. Existing industry codes and standards explicitly address design requirements of new systems, while issues related to system and plant reliability, life, design margins, effects of service conditions, operation, maintenance, etc., usually are implicit. However, system/component design documents of existing power plants often address the code requirements without considering the operation, maintenance, inspection, and testing (OMIT) requirements. The nuclear industry is expending major efforts at most nuclear power plants to reassemble and/or reconstitute system design bases. Stone ampersand Webster Engineering Corporation (SWEC) recently addressed the OMIT requirements of system/component design as an integral part of a utility's preventive maintenance program. For each component, SWEC reviewed vendor recommendations, NPRDS data/industry experience, the existing maintenance program, component service conditions, and actual plant experience. A maintenance program that considers component service conditions and plant experience ensures a connection between maintenance and design basis. Root cause analysis of failure and engineering evaluation of service condition are part of the program. System/component OMIT requirements also are compared against system design, service condition, degradation mechanism, etc., through system/component life-cycle evaluation

Safety constraints applied to an adaptive Bayesian condition-based maintenance optimization model

International Nuclear Information System (INIS)

Flage, Roger; Coit, David W.; Luxhøj, James T.; Aven, Terje

2012-01-01

A model is described that determines an optimal inspection and maintenance scheme for a deteriorating unit with a stochastic degradation process with independent and stationary increments and for which the parameters are uncertain. This model and resulting maintenance plans offers some distinct benefits compared to prior research because the uncertainty of the degradation process is accommodated by a Bayesian approach and two new safety constraints have been applied to the problem: (1) with a given subjective probability (degree of belief), the limiting relative frequency of one or more failures during a fixed time interval is bounded; or (2) the subjective probability of one or more failures during a fixed time interval is bounded. In the model, the parameter(s) of a condition-based inspection scheduling function and a preventive replacement threshold are jointly optimized upon each replacement and inspection such as to minimize the expected long run cost per unit of time, but also considering one of the specified safety constraints. A numerical example is included to illustrate the effect of imposing each of the two different safety constraints.

Computational framework for risk-based planning of inspections, maintenance, and condition monitoring using discrete Bayesian networks

DEFF Research Database (Denmark)

Nielsen, Jannie Sønderkær; Sørensen, John Dalsgaard

2018-01-01

This paper presents a computational framework for risk-based planning of inspections and repairs for deteriorating components. Two distinct types of decision rules are used to model decisions: simple decision rules that depend on constants or observed variables (e.g. inspection outcome...... expecte d life-cycle costs. For advanced decision rules, simulations are performed to estimate the expected costs, and dBNs are used within the simulations for decision-making. Information from inspections and condition monitoring are included if available. An example in the paper demonstrates...... the framework and the implemented strategies and decision rules, including various types of condition-based maintenance. The strategies using advanced decision rules lead to reduced costs compared to the simple decision rules when condition monitoring is applied, and the value of condition monitoring...

Polyspectral signal analysis techniques for condition based maintenance of helicopter drive-train system

Science.gov (United States)

Hassan Mohammed, Mohammed Ahmed

For an efficient maintenance of a diverse fleet of air- and rotorcraft, effective condition based maintenance (CBM) must be established based on rotating components monitored vibration signals. In this dissertation, we present theory and applications of polyspectral signal processing techniques for condition monitoring of critical components in the AH-64D helicopter tail rotor drive train system. Currently available vibration-monitoring tools are mostly built around auto- and cross-power spectral analysis which have limited performance in detecting frequency correlations higher than second order. Studying higher order correlations and their Fourier transforms, higher order spectra, provides more information about the vibration signals which helps in building more accurate diagnostic models of the mechanical system. Based on higher order spectral analysis, different signal processing techniques are developed to assess health conditions of different critical rotating-components in the AH-64D helicopter drive-train. Based on cross-bispectrum, quadratic nonlinear transfer function is presented to model second order nonlinearity in a drive-shaft running between the two hanger bearings. Then, quadratic-nonlinearity coupling coefficient between frequency harmonics of the rotating shaft is used as condition metric to study different seeded shaft faults compared to baseline case, namely: shaft misalignment, shaft imbalance, and combination of shaft misalignment and imbalance. The proposed quadratic-nonlinearity metric shows better capabilities in distinguishing the four studied shaft settings than the conventional linear coupling based on cross-power spectrum. We also develop a new concept of Quadratic-Nonlinearity Power-Index spectrum, QNLPI(f), that can be used in signal detection and classification, based on bicoherence spectrum. The proposed QNLPI(f) is derived as a projection of the three-dimensional bicoherence spectrum into two-dimensional spectrum that

Optimal condition-based maintenance decisions for systems with dependent stochastic degradation of components

International Nuclear Information System (INIS)

Hong, H.P.; Zhou, W.; Zhang, S.; Ye, W.

2014-01-01

Components in engineered systems are subjected to stochastic deterioration due to the operating environmental conditions, and the uncertainty in material properties. The components need to be inspected and possibly replaced based on preventive or failure replacement criteria to provide the intended and safe operation of the system. In the present study, we investigate the influence of dependent stochastic degradation of multiple components on the optimal maintenance decisions. We use copula to model the dependent stochastic degradation of components, and formulate the optimal decision problem based on the minimum expected cost rule and the stochastic dominance rules. The latter is used to cope with decision maker's risk attitude. We illustrate the developed probabilistic analysis approach and the influence of the dependency of the stochastic degradation on the preferred decisions through numerical examples

Maintenance cost avoidance through comprehensive condition monitoring

International Nuclear Information System (INIS)

Miller, G.P.; McClymonds, S.L.

1990-01-01

Condition monitoring, the measurement and trending of a critical parameter for predictive maintenance, has reached new levels of acceptance and application within the utility and manufacturing industry. Commercially available systems extend well beyond traditional vibration-monitoring systems to include such areas as online wear, crack and leak detection, and stress monitoring. The challenge facing industry is to integrate the information generated from condition monitoring. Current studies indicate that the effectiveness of predictive maintenance depends much more on the program that is established to apply the monitoring techniques than on the monitoring equipment itself. This paper presents a five-phase approach to developing a condition monitoring program

Risk-Based Operation and Maintenance of Offshore Wind Turbines

DEFF Research Database (Denmark)

Nielsen, Jannie Sønderkær

to oil and gas structures. In addition, condition monitoring systems are often available, and the information should be taken into account when making decisions. In this thesis, methods for risk-based maintenance planning using Bayesian methods are investigated, with the aim of making optimal decisions......, but presently maintenance is not planned using advanced methods taking all available information into account in a consistent manner. Maintenance decisions can be made based on risk-based methods, where the total expected life cycle costs are minimized. Methods have been developed for assessing the corrective...... considering all available information. First, a theoretical damage model is formulated, the model is then updated using condition monitoring data, and the updated model is used as basis for risk-based decision making. Several approaches for solving the decision problems have been considered: various types...

Performance-based inspection and maintenance strategies

International Nuclear Information System (INIS)

Vesely, W.E.

1995-01-01

Performance-based inspection and maintenance strategies utilize measures of equipment performance to help guide inspection and maintenance activities. A relevant measure of performance for safety system components is component unavailability. The component unavailability can also be input into a plant risk model such as a Probabilistic Risk Assessment (PRA) to determine the associated plant risk performance. Based on the present and projected unavailability performance, or the present and projected risk performance, the effectiveness of current maintenance activities can be evaluated and this information can be used to plan future maintenance activities. A significant amount of information other than downtimes or failure times is collected or can be collected when an inspection or maintenance is conducted which can be used to estimate the component unavailability. This information generally involves observations on the condition or state of the component or component piecepart. The information can be detailed such as the amount of corrosion buildup or can be general such as the general state of the component described as ' high degradation', ' moderate degradation', or ' low degradation'. Much of the information collected in maintenance logs is qualitative and fuzzy. As part of an NRC Research program on performance-based engineering modeling, approaches have been developed to apply Fuzzy Set Theory to information collected on the state of the component to determine the implied component or component piecepart unavailability. Demonstrations of the applications of Fuzzy Set Theory are presented utilizing information from plant maintenance logs. The demonstrations show the power of Fuzzy Set Theory in translating engineering information to reliability and risk implications

Condition-based maintenance for complex systems : Coordinating maintenance and logistics planning for the process industries

NARCIS (Netherlands)

Olde Keizer, Minou Catharina Anselma

2016-01-01

Maintenance planning in the process industries is extremely complex for various reasons. Plants often run nonstop, allowing little time for performing preventive maintenance. Failures should be prevented, however, as they can lead to system downtime and high losses of revenue. Corrective maintenance

Condition-based maintenance at both scheduled and unscheduled opportunities

NARCIS (Netherlands)

Kalosi, S.; Kapodistria, S.; Resing, J.A.C.

2016-01-01

Motivated by original equipment manufacturer (OEM) service and maintenance practices we consider a single component subject to replacements at failure instances and two types of preventive maintenance opportunities: scheduled, which occur due to periodic system reviews of the equipment, and

Maintenance Decision Based on Data Fusion of Aero Engines

Directory of Open Access Journals (Sweden)

Huawei Wang

2013-01-01

Full Text Available Maintenance has gained a great importance as a support function for ensuring aero engine reliability and availability. Cost-effectiveness and risk control are two basic criteria for accurate maintenance. Given that aero engines have much condition monitoring data, this paper presents a new condition-based maintenance decision system that employs data fusion for improving accuracy of reliability evaluation. Bayesian linear model has been applied, so that the performance degradation evaluation of aero engines could be realized. A reliability evaluation model has been presented based on gamma process, which achieves the accurate evaluation by information fusion. In reliability evaluation model, the shape parameter is estimated by the performance degradation evaluation result, and the scale parameter is estimated by failure, inspection, and repair information. What is more, with such reliability evaluation as input variables and by using particle swarm optimization (PSO, a stochastic optimization of maintenance decision for aircraft engines has been presented, in which the effectiveness and the accuracy are demonstrated by a numerical example.

Maintenance cost optimization in condition based maintenance: a case study for critical facilities

OpenAIRE

Filippo De Carlo; Maria Antonietta Arleo

2013-01-01

The increasing availability required to industrial plants and the limited budget often existing to assure it, require a careful formulation of maintenance optimization models. This need is primary for process plants, for which minimization of stops and maximization of their availability, are essential for ensuring targeted production and, therefore, profitability. In this context, the choice of the maintenance strategy is hence fundamental, depending on the system features and then on the eff...

Experimental study on the plant state estimation for the condition-based maintenance

International Nuclear Information System (INIS)

Harada, J. I.; Takahashi, M.; Kitamura, M.; Wakabayashi, T.

2006-01-01

A framework of maintenance support system based on the plant state estimation using diverse methods has been proposed and the validity of the plant state estimation methods has been experimentally evaluated. The focus has been set on the construction of the BN for the objective system with the scale and complexity as same as real world systems. Another focus has been set on the other functions for maintenance support system such as signal processing tool and similarity matching. The validity of the proposed inference method has been confirmed through numerical experiments. (authors)

Risk-based Operation and Maintenance for Offshore Wind Turbines

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard; Nielsen, Jannie Jessen

2011-01-01

For offshore wind turbines, costs to Operation and Maintenance (OM) are substantial, and can be expected to increase when wind farms are placed at deeper water depths and in more harsh environments. Traditional strategies for OM include corrective and preventive (scheduled and condition...... statistics and costs of the different operations. The different OM strategies are described and compared in an illustrative example with focus on which types of information that are needed. Special focus is on comparison between risk-based maintenance strategies and the conventional maintenance planning...... and are often the driving mechanisms for failures / faults that need maintenance. Observations of the degree of damage can increase the reliability of predictions and decrease the costs of OM if integrated in a risk-based framework theoretically based on pre-posterior Bayesian decision theory. The mathematical...

Age-dependent reliability model considering effects of maintenance and working conditions

International Nuclear Information System (INIS)

Martorell, Sebastian; Sanchez, Ana; Serradell, Vicente

1999-01-01

Nowadays, there is some doubt about building new nuclear power plants (NPPs). Instead, there is a growing interest in analyzing the possibility to extend current NPP operation, where life management programs play an important role. The evolution of the NPP safety depends on the evolution of the reliability of its safety components, which, in turn, is a function of their age along the NPP operational life. In this paper, a new age-dependent reliability model is presented, which includes parameters related to surveillance and maintenance effectiveness and working conditions of the equipment, both environmental and operational. This model may be used to support NPP life management and life extension programs, by improving or optimizing surveillance and maintenance tasks using risk and cost models based on such an age-dependent reliability model. The results of the sensitivity study in the example application show that the selection of the most appropriate maintenance strategy would directly depend on the previous parameters. Then, very important differences are expected to appear under certain circumstances, particularly, in comparison with other models that do not consider maintenance effectiveness and working conditions simultaneously

A Novel Idea for Optimizing Condition-Based Maintenance Using Genetic Algorithms and Continuous Event Simulation Techniques

Directory of Open Access Journals (Sweden)

Mansoor Ahmed Siddiqui

2017-01-01

Full Text Available Effective maintenance strategies are of utmost significance for system engineering due to their direct linkage with financial aspects and safety of the plants’ operation. At a point where the state of a system, for instance, level of its deterioration, can be constantly observed, a strategy based on condition-based maintenance (CBM may be affected; wherein upkeep of the system is done progressively on the premise of monitored state of the system. In this article, a multicomponent framework is considered that is continuously kept under observation. In order to decide an optimal deterioration stage for the said system, Genetic Algorithm (GA technique has been utilized that figures out when its preventive maintenance should be carried out. The system is configured into a multiobjective problem that is aimed at optimizing the two desired objectives, namely, profitability and accessibility. For the sake of reality, a prognostic model portraying the advancements of deteriorating system has been employed that will be based on utilization of continuous event simulation techniques. In this regard, Monte Carlo (MC simulation has been shortlisted as it can take into account a wide range of probable options that can help in reducing uncertainty. The inherent benefits proffered by the said simulation technique are fully utilized to display various elements of a deteriorating system working under stressed environment. The proposed synergic model (GA and MC is considered to be more effective due to the employment of “drop-by-drop approach” that permits successful drive of the related search process with regard to the best optimal solutions.

Integrated reliability condition monitoring and maintenance of equipment

CERN Document Server

Osarenren, John

2015-01-01

Consider a Viable and Cost-Effective Platform for the Industries of the Future (IOF) Benefit from improved safety, performance, and product deliveries to your customers. Achieve a higher rate of equipment availability, performance, product quality, and reliability. Integrated Reliability: Condition Monitoring and Maintenance of Equipment incorporates reliable engineering and mathematical modeling to help you move toward sustainable development in reliability condition monitoring and maintenance. This text introduces a cost-effective integrated reliability growth monitor, integrated reliability degradation monitor, technological inheritance coefficient sensors, and a maintenance tool that supplies real-time information for predicting and preventing potential failures of manufacturing processes and equipment. The author highlights five key elements that are essential to any improvement program: improving overall equipment and part effectiveness, quality, and reliability; improving process performance with maint...

Sensitivity of Risk-Based Maintenance Planning of Offshore Wind Turbine Farms

DEFF Research Database (Denmark)

Ambühl, Simon; Sørensen, John Dalsgaard

2017-01-01

Inspection and maintenance expenses cover a considerable part of the cost of energy from offshore wind turbines. Risk-based maintenance planning approaches are a powerful tool to optimize maintenance and inspection actions and decrease the total maintenance expenses. Risk-based planning is based...... on many input parameters, which are in reality often not completely known. This paper will assess the cost impact of this incomplete knowledge based on a case study following risk-based maintenance planning. The sensitivity study focuses on weather forecast uncertainties, incomplete knowledge about...... the needed repair time on the site as well as uncertainties about the operational range of the boat and helicopter used to access the broken wind turbine. The cost saving potential is estimated by running Crude Monte Carlo simulations. Furthermore, corrective and preventive (scheduled and condition...

Assessment of diagnostic and prognostic condition indices for efficient and robust maintenance decision-making of systems subject to stress corrosion cracking

International Nuclear Information System (INIS)

Huynh, K.T.; Grall, A.; Bérenguer, C.

2017-01-01

Seeking condition indices characterizing the health state of a system is a key problem in condition-based maintenance. For this purpose, diagnostic and prognostic models have been unceasingly developed and improved over the past few decades; nevertheless none of them explains thoroughly the impacts of such indices on the effectiveness of maintenance operations. As a complement to these efforts, this paper analyzes the effectiveness of some well-known diagnostic and prognostic indices for maintenance decision-making. The study is based on a system subject to competing risks due to multiple crack paths. A periodic inspection scheme is used to monitor the system health state. Each inspection returns the perfect diagnostic information: the number of cracks, corresponding crack sizes, and the system failure/working state. Based on this information, two kinds of prognostic condition indices are predicted: the average value and probability law of the system residual useful life. The associated condition-based maintenance strategies and cost models are then developed and compared with the ones whose maintenance decisions are based on diagnostic condition indices. The comparison results allow us to conclude on the performance and on the robustness of these strategies, hence giving some suggestions on the choice of reliable condition indices for maintenance decision-making. - Highlights: • Developing a new and generic degradation and failure model. • Synthesizing diagnostic and prognostic condition indices on the basis of the developed degradation and failure model. • Building diagnosis and prognosis-based maintenance strategies, and developing the associated cost models. • Assessing the performance and robustness of the considered strategies to find out reliable indices.

The Road Pavement Condition Index (PCI Evaluation and Maintenance: A Case Study of Yemen

Directory of Open Access Journals (Sweden)

Karim Fareed M. A.

2016-12-01

Full Text Available The pavement condition index (PCI is a simple, convenient and inexpensive way to monitor the condition of the surface of roads, identify maintenance and rehabilitation (M-and-R needs as well as ensure that road maintenance budgets are spent wisely. In this research, the pavement condition was evaluated in terms of the surface distresses existing at the time of the field evaluation. The PCI procedure was used in this research because it deals with the subject of pavement distress identification most comprehensively and is based on a sound statistical technique of pavement sampling.

Prioritization of pavement maintenance sections using objective based Analytic Hierarchy Process

Directory of Open Access Journals (Sweden)

Sarfaraz Ahmed

2017-03-01

Full Text Available The application of Analytic Hierarchy Process (AHP method for the prioritization of pavement maintenance sections is widespread now-a-days. Although the evaluation of pavement maintenance section through AHP method is simple, where the relative importance (on Saaty’s scale assigned to each parameter in the hierarchy varies between the experts (transportation professionals consulted, which leads to discrepancies in the final rankings of the sections’, due to the subjectivity in the process. Further, experts base their decisions solely on their experience while consideration is not given to the actual quantitative physical condition of the roads. To overcome these difficulties an objective based AHP method is proposed in this study, where pairwise comparison values are assigned based on the collected field data from a road network in Mumbai city, consisting of 28 road sections. The final ranking list of candidate sections takes into consideration the priority weight of alternatives, which reflect the road conditions. The solution of priority ratings of AHP method is compared with the corresponding solution of road condition index method, a traditional pavement maintenance procedure. The findings of the present study suggest that objective based AHP method is more suitable for the prioritization of pavement maintenance of roads. Keywords: Prioritization, Analytic Hierarchy Process, Road condition index, Objective method, Rating and ranking

Risk-Based Operation and Maintenance Planning for Offshore Wind Turbines

DEFF Research Database (Denmark)

Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

2010-01-01

Operation and maintenance (O&M) are large contributors to the cost of energy for offshore wind turbines. Optimal planning of O&M should include use of inspections and monitoring results to make decisions that minimize the expected costs through the lifetime of the structures. For offshore...... structures it is especially important because of the dependence on weather windows for inspections and repairs to be possible. A model has been developed to estimate the expected costs to corrective and condition based maintenance for a wind turbine with a single component. The deterioration of the component...... is simulated, and the expected costs are found for different strategies. An application example shows that condition based maintenance has the potential of reducing the costs, and a risk based approach can be used to find the optimal strategy for O&M. Further the influence of failure rate and damage parameters...

Gym-based exercise and home-based exercise with telephone support have similar outcomes when used as maintenance programs in adults with chronic health conditions: a randomised trial

Directory of Open Access Journals (Sweden)

Paul Jansons

2017-07-01

Trial registration: ACTRN12610001035011. [Jansons P, Robins L, O’Brien L, Haines T (2017 Gym-based exercise and home-based exercise with telephone support have similar outcomes when used as maintenance programs in adults with chronic health conditions: a randomised trial. Journal of Physiotherapy 63: 154–160

Implementation strategies and tools for condition based monitoring at nuclear power plants

International Nuclear Information System (INIS)

2007-05-01

There is now an acute need to optimize maintenance to improve both reliability and competitiveness of nuclear power plant operation. There is an increasing tendency to move from the preventive (time based) maintenance concept to one dependent on plant and component conditions. In this context, various on-line and off-line condition monitoring and diagnostics, nondestructive inspection techniques and surveillance are used. Component selection for condition based maintenance, parameter selection for monitoring condition, evaluation of condition monitoring results are issues influencing the effectiveness of condition based maintenance. All these selections of components and parameters to be monitored, monitoring and diagnostics techniques to be used, acceptance criteria and trending for condition evaluation, and the economic aspect of predictive maintenance and condition monitoring should be incorporated into an integrated, effective condition based maintenance programme, which is part of the plant's overall maintenance optimization programme. This publication collects and analyses proven condition based maintenance strategies and techniques (engineering and organizational) in Member States. It includes selected papers on maintenance optimization presented during its preparation. This report was prepared under IAEA project on integrated NPP life cycle management including decommissioning. The main objective of an integrated life cycle management programme is to enable NPP's to compete, without compromising safety, successfully in the changing energy markets throughout their service life and to facilitate life extension and eventual decommissioning through improved engineering, technological, economic and managerial actions. The technical working group on NPP life management and other advisory groups nominated by the Member States provide recommendations on high priority needs of Member States in this area

Ageing model considering effects of maintenance and working conditions

International Nuclear Information System (INIS)

Martorell, S.; Sanchez, A.; Serradell, V.

1998-01-01

Nowadays, there is some doubt about building new Nuclear Power Plants (NPPs). Instead, there is a growing interest in analyzing the possibility to extend current NPP operation where life management programs play an important role. The evolution of the NPP safety depends on the evolution of the reliability of its safety components as a function of their age along the NPP operational life. In this paper, a new age-dependent reliability model is presented, which includes parameters related to surveillance and maintenance effectiveness and working conditions, both environmental and operational, of the equipment. This model may be used to support NPP life management and life extension programs by improving or optimizing surveillance and maintenance tasks using risk and cost models based on such an age-dependent reliability model. The results of the sensitivity study in the application show that the selection of the most appropriate maintenance strategy would directly depend on the previous parameters and very important differences are expected to appear under certain circumstance. (Author) 7 refs

Maintenance Planning of Offshore Wind Turbine using Condition Monitoring Information

DEFF Research Database (Denmark)

Ramírez, José G. Rangel; Sørensen, John Dalsgaard

2009-01-01

Deterioration processes such as fatigue and corrosion are typically affecting offshore structures. To "control" this deterioration, inspection and maintenance activities are developed. Probabilistic methodologies represent an important tool to identify the suitable strategy to inspect and control...... the deterioration in structures such as offshore wind turbines (OWT). Besides these methods, the integration of condition monitoring information (CMI) can optimize the mitigation activities as an updating tool. In this paper, a framework for risk-based inspection and maintenance planning (RBI) is applied for OWT....... With the integration of CMI by means Bayesian inference, a slightly change of first inspection times are coming up, influenced by the reduction of the uncertainty and harsher or milder external agents....

Condition monitoring a key component in the preventive maintenance

International Nuclear Information System (INIS)

Isar, C.

2006-01-01

The preventive maintenance programs are necessary to ensure that nuclear safety significant equipment will function when it is supposed to. Diesel generator, pumps, motor operated valves and air operated control valves are typically operated every three months. When you drive a car, you depend on lot of sounds, the feel of the steering wheel and gauges to determine if the car is running correctly. Similarly with operating equipment for a power plant - sounds or vibration of the equipment or the gauges and test equipment indicate a problem or degradation, actions are taken to correct the deficiency. Due to safety and economical reason diagnostic and monitoring systems are of growing interest in all complex industrial production. Diagnostic systems are requested to detect, diagnose and localize faulty operating conditions at an early stage in order to prevent severe failures and to enable predictive and condition oriented maintenance. In this context it is a need for using various on-line and off-line condition monitoring and diagnostics, non-destructive inspection techniques and surveillance. The condition monitoring technique used in nuclear power plant Cernavoda are presented in this paper. The selection of components and parameters to be monitored, monitoring and diagnostics techniques used are incorporated into a preventive maintenance program. Modern measurement technique in combination with advanced computerized data processing and acquisition show new ways in the field of machine surveillance. The diagnostic capabilities of predictive maintenance technologies have increased recently year with advances made in sensor technologies. The paper will focus on the following condition monitoring technique: - oil analysis - acoustic leakage monitoring - thermography - valve diagnostics: motor operated valve, air operated valve and check valve - motor current signature - vibration monitoring and rotating machine monitoring and diagnostics For each condition monitoring

Risk based maintenance: Resource requirements and organizational challenges

International Nuclear Information System (INIS)

Weerakkody, S.D.

2000-01-01

10CFR50.65 'Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants' required licensees to monitor the performance or condition of structures, systems, or components (SSCs) against licensee established goals, in a manner sufficient to provide reasonable assurance that such SSCs are capable of fulfilling their intended functions. The goals were required to be commensurate with safety significance and operating experience. Northeast Utilities relied upon PRAs to implement 10CFR50.65, which is also referred to as the 'Maintenance Rule'. The Maintenance Rule changed some aspects of maintenance of structures, systems, and components (SSC) at nuclear power plants. One objective of the rule was to focus the maintenance resources based on risk significance of components. This paper will discuss the organizational challenges and resource requirements associated with implementation of the Maintenance Rule at nuclear facilities that are supported by the Northeast Utilities Services Company (NUSCo). The paper will discuss (a) how these challenges were addressed, (b) the resources required for ongoing efforts to support the Maintenance Rule, and (c) several key safety benefits derived from the implementation of the Maintenance Rule. (author)

Preventive maintenance: optimization of time - based discard decisions at the bruce nuclear generating station

International Nuclear Information System (INIS)

Doyle, E.K.; Jardine, A.K.S.

2001-01-01

The use of various maintenance optimization techniques at Bruce has lead to cost effective preventive maintenance applications for complex systems. As previously reported at ICONE 6 in New Orleans, 1996, several innovative practices reduced Reliability Centered Maintenance costs while maintaining the accuracy of the analysis. The optimization strategy has undergone further evolution and at the present an Integrated Maintenance Program (IMP) is in place where an Expert Panel consisting of all players/experts proceed through each system in a disciplined fashion and reach agreement on all items under a rigorous time frame. It is well known that there are essentially 3 maintenance based actions that can flow from a Maintenance Optimization Analysis: condition based maintenance, time based maintenance and time based discard. The present effort deals with time based discard decisions. Maintenance data from the Remote On-Power Fuel Changing System was used. (author)

Condition-Based Maintenance Strategy for Production Systems Generating Environmental Damage

Directory of Open Access Journals (Sweden)

L. Tlili

2015-01-01

Full Text Available We consider production systems which generate damage to environment as they get older and degrade. The system is submitted to inspections to assess the generated environmental damage. The inspections can be periodic or nonperiodic. In case an inspection reveals that the environmental degradation level has exceeded the critical level U, the system is considered in an advanced deterioration state and will have generated significant environmental damage. A corrective maintenance action is then performed to renew the system and clean the environment and a penalty has to be paid. In order to prevent such an undesirable situation, a lower threshold level L is considered to trigger a preventive maintenance action to bring back the system to a state as good as new at a lower cost and without paying the penalty. Two inspection policies are considered (periodic and nonperiodic. For each one of them, a mathematical model and a numerical procedure are developed to determine simultaneously the preventive maintenance (PM threshold L∗ and the inspection sequence which minimize the average long-run cost per time unit. Numerical calculations are performed to illustrate the proposed maintenance policies and highlight their main characteristics with respect to relevant input parameters.

Risk-based maintenance-Techniques and applications

International Nuclear Information System (INIS)

Arunraj, N.S.; Maiti, J.

2007-01-01

Plant and equipment, however well designed, will not remain safe or reliable if it is not maintained. The general objective of the maintenance process is to make use of the knowledge of failures and accidents to achieve the possible safety with the lowest possible cost. The concept of risk-based maintenance was developed to inspect the high-risk components usually with greater frequency and thoroughness and to maintain in a greater manner, to achieve tolerable risk criteria. Risk-based maintenance methodology provides a tool for maintenance planning and decision making to reduce the probability of failure of equipment and the consequences of failure. In this paper, the risk analysis and risk-based maintenance methodologies were identified and classified into suitable classes. The factors affecting the quality of risk analysis were identified and analyzed. The applications, input data and output data were studied to understand their functioning and efficiency. The review showed that there is no unique way to perform risk analysis and risk-based maintenance. The use of suitable techniques and methodologies, careful investigation during the risk analysis phase, and its detailed and structured results are necessary to make proper risk-based maintenance decisions

Sustainable resilience in property maintenance: encountering changing weather conditions

DEFF Research Database (Denmark)

Cox, Rimante Andrasiunaite; Nielsen, Susanne Balslev

2014-01-01

Purpose: The purpose of the study is to develop a methodological approach for project management to integrate sustainability and resilience planning in property maintenance as an incremental strategy for upgrading existing properties to meet new standards for sustainable and climate resilient...... buildings. Background: Current maintenance practice is focused on the technical standard of buildings, with little consideration of sustainability and resilience. There is a need to develop tools for incorporating sustainable resilience into maintenance planning. Approach: The study is primarily theoretical......, developing the concept of sustainable resilience for changing weather conditions Results: The paper suggests a decision support methodology that quantifies sustainable resilience for the analytical stages of property maintenance planning. Practical Implications: The methodology is generic and expected users...

Integrated Instrumentation and Sensor Systems Enabling Condition-Based Maintenance of Aerospace Equipment

Directory of Open Access Journals (Sweden)

Richard C. Millar

2012-01-01

Full Text Available The objective of the work reported herein was to use a systems engineering approach to guide development of integrated instrumentation/sensor systems (IISS incorporating communications, interconnections, and signal acquisition. These require enhanced suitability and effectiveness for diagnostics and health management of aerospace equipment governed by the principles of Condition-based maintenance (CBM. It is concluded that the systems engineering approach to IISS definition provided clear benefits in identifying overall system requirements and an architectural framework for categorizing and evaluating alternative architectures, relative to a bottom up focus on sensor technology blind to system level user needs. CBM IISS imperatives identified include factors such as tolerance of the bulk of aerospace equipment operational environments, low intrusiveness, rapid reconfiguration, and affordable life cycle costs. The functional features identified include interrogation of the variety of sensor types and interfaces common in aerospace equipment applications over multiplexed communication media with flexibility to allow rapid system reconfiguration to adapt to evolving sensor needs. This implies standardized interfaces at the sensor location (preferably to open standards, reduced wire/connector pin count in harnesses (or their elimination through use of wireless communications.

Tools to support maintenance strategies under soft soil conditions

Directory of Open Access Journals (Sweden)

J. W. M. Lambert

2015-11-01

Full Text Available Costs for maintenance of infrastructure in municipalities with soft soil underground conditions, are estimated to be almost 40 % higher than in others. As a result, these municipalities meet financial problems that cause overdue maintenance. In some cases municipalities are even afraid to be unable to offer a minimum service level in future. In common, traditional practice, roads and sewerage systems have been constructed in trenches that consist of sandy material that replaces the upper meters of the soft soil. Under influence of its weight, this causes accelerated settlements of the construction. A number of alternative constructions have been developed, e.g. using light-weight materials to limit settlement velocity. In order to limit future maintenance costs, improvement of maintenance strategies is desired. Tools have been and will be developed to support municipalities in improving their maintenance strategies and save money by doing that. A model (BALANS that weighs the attractiveness of alternative solutions under different soil, environmental and economic circumstances, will be presented.

Maintenance of electromechanical equipment in quality organization under operating conditions

International Nuclear Information System (INIS)

Mercier, J.P.

1984-01-01

The paper outlines the principles adopted by the Thermal Production Service of Electricite de France on the basis of the experience of the first years of operation of its 900 MW(e)PWR units for the purpose of improving quality organization in operating conditions in respect of the maintenance of electromechanical safety equipment. This organization is based on application of the usual principles for quality assurance, adapted in accordance with current French regulations. The paper first recalls the now traditional methods of applying the principles of quality organization in the area of equipment maintenance. It then defines particular so-called ''delicate'' activities which, in accordance with the above regulations, are subjected to additional quality organizational procedures; this applies in particular to the area of pre-maintenance preparation and studies and to the control exercised by the French safety authorities over the execution of those activities. The paper explains how the application of the regulations improves maintenance practices compared with standard quality organization. It describes how the attempt to establish a frontier between these two types of activity (current and ''delicate'') has led to the definition of a classification criterion which is technically correct and simple to use and is based on the professional skills of those performing each activity. The paper then describes in greater detail the principal rules for the performance of those tasks which come under the standard organization and those to which more stringent criteria apply. Lastly, it explains the thinking behind equipment surveillance programmes and the analysis of anomalies discovered through surveillance measures or brought to light by operating incidents, the aim of these being to benefit from the experience gained

Optimizing preventive maintenance with maintenance templates

International Nuclear Information System (INIS)

Dozier, I.J.

1996-01-01

Rising operating costs has caused maintenance professionals to rethink their strategy for preventive maintenance (PM) programs. Maintenance Templates are pre-engineered PM task recommendations for a component type based on application of the component. Development of the maintenance template considers the dominant failure cause of the component and the type of preventive maintenance that can predict or prevent the failure from occurring. Maintenance template development also attempts to replace fixed frequency tasks with condition monitoring tasks such as vibration analysis or thermography. For those components that have fixed frequency PM intervals, consideration is given to the maintenance drivers such as criticality, environment and usage. This helps to maximize the PM frequency intervals and maximize the component availability. Maintenance Templates have been used at PECO Energy's Limerick Generating Station during the Reliability Centered Maintenance (RCM) Process to optimize their PM program. This paper describes the development and uses of the maintenance templates

A Novel Short-Term Maintenance Strategy for Power Transmission and Transformation Equipment Based on Risk-Cost-Analysis

Directory of Open Access Journals (Sweden)

Hang Yang

2017-11-01

Full Text Available Current studies on preventive condition-based maintenance of power transmission and transformation equipment mainly focus on mid-term or long-term maintenance, and cannot meet the requirements of short-term especially temporary maintenance. In order to solve the defects of the present preventive maintenance strategies, according to the engineering application and based on risk-cost analysis, a short-term maintenance strategy is proposed in this manuscript. For the equipment working in bad health condition, its active maintenance costs and operation risk costs are evaluated, respectively. Then the latest maintenance time is calculated in accordance with the principle that its operation risk costs are no higher than active maintenance costs. Utilizing the latest maintenance time, the best maintenance time is calculated by setting the maximum relative earnings of postponing maintenance as the target, which provides the operation staffs with comprehensive maintenance-decision support. In the end, different cases on the IEEE 24-bus system are simulated. The effectiveness and advantages of the proposed strategy are demonstrated by the simulation results.

Maintenance management for nuclear power plant 'Integrated valve maintenance'

International Nuclear Information System (INIS)

Gerner, P.; Zanner, G.

2001-01-01

The deregulation of Europe's power market does force many utilities, and especially nuclear power plant operators, to introduce extensive cost-cutting measures in order to be able to compete within this new environment. The optimization of plant outages provides considerable potential for raising plant availability but can also lower operating costs by reducing e.g. expenditure on maintenance. Siemens Nuclear Power GmbH, in cooperation with plant operators, is currently implementing new and improved service concepts which can have a major effect on the way in which maintenance will be performed in the future. Innovative service packages for maintenance in nuclear power plants are available which can be used to perform a time- and cost-effective maintenance. The concepts encompass optimization of the overall sequence from planning in advance to the individual measures including reduction of the scope of maintenance activities, identification of cost cutting potential and bundling of maintenance activities. The main features of these maintenance activities are illustrated here using the examples of outage planning and integrated valve maintenance. In nuclear power plants approx. 5000 valves are periodically preventively, condition-based or breakdown-based maintained. Because of this large number of valves to be maintained a high potential of improvements and cost reductions can be achieved by performing an optimized, cost-effective maintenance based on innovative methods and tools. Siemens Nuclear Power GmbH has developed and qualified such tools which allow to reduce service costs while maintaining high standards of safety and availability. By changing from preventive to predictive (condition-based) maintenance - the number of valves to be maintained may be reduced considerably. The predictive maintenance is based on the Siemens Nuclear Power GmbH diagnostic and evaluation method (ADAM). ADAM is used to monitor the operability of valves by analytical verification of

Predictive maintenance: A new approach in maintenance of nuclear power plants

International Nuclear Information System (INIS)

Benvenuto, F.; Ferrari, L.

2005-01-01

The maintenance services for a Nuclear Power Plant are in general aimed at reaching the following goals: - Increase component availability and consequently decrease intervention frequency; - Reduce unexpected costs from unexpected repairs; - Progressively decrease the time of each intervention; - Improve the spare parts supply efficiency; - Improve spare parts and consumable warehouse managing; - Decrease maintenance costs. Most of the currently used maintenance activities refer to run-to-failure or preventive approaches: - Run-to-failure or Corrective Maintenance means that work is only carried out when a component or system is faulty and unable to perform its critical function. Non critical components such as filters or components with spare may be maintained in this way; - Preventive or Scheduled Maintenance involves a regular pre-set schedule programme of maintenance work. Programme outlined by the manufacturer of the component in question based on the design life of the component and based on past experience by operation. One step further than Preventive Maintenance is represented by Predictive Maintenance. Whereas Preventive Maintenance bases its schedules on past performance data, a predictive system acquires condition data from the machine to be maintained whilst the machine is in operation. The information obtained from this analysis indicates the condition in real time, provides a diagnosis of wear and shows any trend towards critical conditions. Predictive maintenance mainly consists of the following interventions: - Lubricant analysis; - Collection / analysis of functional parameters, such as motor absorption, flow rate, pressure, temperature, noise, vibration of rotating equipment, thermal efficiency, etc; - Periodical test of lifting systems; - Other operations to acquire sensitive equipment parameters. Predictive Maintenance can reduce the accidental intervention and extend the components life, and, in the end, is increasing the global availability

Condition-based dynamic maintenance operations planning and grouping. Application to commercial heavy vehicles

Energy Technology Data Exchange (ETDEWEB)

Bouvard, K., E-mail: keomany.bouvard@volvo.co [Volvo Technology, 99 route de Lyon, 69806 Saint Priest cedex (France); Laboratoire d' Automatique de Genie Informatique et Signal - FRE3303 - Polytech' Lille, 59655 Villeneuve d' Ascq (France); Artus, S., E-mail: samuel.artus@volvo.co [Volvo Technology, 99 route de Lyon, 69806 Saint Priest cedex (France); Berenguer, C., E-mail: christophe.berenguer@utt.f [Universite de technologie de Troyes - Institut Charles Delaunay and UMR CNRS 6279 - 12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Cocquempot, V., E-mail: vincent.cocquempot@univ-lille1.f [Laboratoire d' Automatique de Genie Informatique et Signal - FRE3303 - Polytech' Lille, 59655 Villeneuve d' Ascq (France)

2011-06-15

This paper aims at presenting a method to optimize the maintenance planning for a commercial heavy vehicle. Such a vehicle may be considered as a multi-components system. Grouping maintenance operations related to each component reduces the global maintenance cost of the system. Classically, the optimization problem is solved using a priori reliability characteristics of components. Two types of methods may be used, i.e. static or dynamic methods. Static methods provide a fixed maintenance planning, whereas dynamic methods redefine the groups of maintenance operations at each decision time. Dynamic procedures can incorporate component information such as component states or detected failures. For deteriorating systems, reliability characteristics of each component may be estimated thanks to deterioration models and may be updated when a degradation measure is available. This additional information on degradation features allows to better follow the real state of each component and to improve the maintenance planning.

Control-limit preventive maintenance policies for components subject to imperfect preventive maintenance and variable operational conditions

International Nuclear Information System (INIS)

You Mingyi; Li Hongguang; Meng Guang

2011-01-01

This paper develops two component-level control-limit preventive maintenance (PM) policies for systems subject to the joint effect of partial recovery PM acts (imperfect PM acts) and variable operational conditions, and investigates the properties of the proposed policies. The extended proportional hazards model (EPHM) is used to model the system failure likelihood influenced by both factors. Several numerical experiments are conducted for policy property analysis, using real lifetime and operational condition data and typical characterization of imperfect PM acts and maintenance durations. The experimental results demonstrate the necessity of considering both factors when they do exist, characterize the joint effect of the two factors on the performance of an optimized PM policy, and explore the influence of the loading sequence of time-varying operational conditions on the performance of an optimized PM policy. The proposed policies extend the applicability of PM optimization techniques.

Simulation based comparison of predictive maintenance policies

NARCIS (Netherlands)

Tinga, Tiedo; Janssen, R.H.P.; Steenbergen, R.; van Gelder, P.

2013-01-01

When an asset is operated in variable conditions, its operational efficiency can be improved significantly when the maintenance is performed in a dynamic manner. This means that variations in usage and operating environment are taken into account when deciding on the length of the maintenance

Remediation of Gremikha Coastal maintenance base - status of the project

International Nuclear Information System (INIS)

Pillette-Cousin, L.; Stepennov, B.S.; Gorbatchev, A.

2008-01-01

The former coastal maintenance base in Gremikha is located in the Kola Peninsula, along the Barents Sea, about 300 km east from Murmansk. There is no road or railway to get there, therefore the only possible connection is either by sea or by helicopter. Remediation of the Gremikha coastal maintenance base (CMB) is now one of the main priorities for Rosatom (the Agency for Atomic Energy of the Russian Federation) because nuclear and radioactive waste are currently stored in conditions which do not meet the up-to-date safety and regulatory requirements and it might represent an environmental hazard and a risk of misappropriation of the nuclear material stored there. (authors)

A STEPPING STONE TOWARDS KNOWLEDGE BASED MAINTENANCE

OpenAIRE

G. Waeyenbergh; L. Pintelon; L. Gelders

2012-01-01

Maintenance decision making becomes more and more a management concern. Some decades ago, maintenance was still often considered as an unavoidable side effect of production. The perception of maintenance has evolved considerably. One of the current issues is the maintenance concept, being the mix of maintenance interventions and the general framework for determining this mix. In this paper we describe a modular framework, called Knowledge Based Maintenance, for developing a customised mainten...

Equipment Maintenance management support system based on statistical analysis of maintenance history data

International Nuclear Information System (INIS)

Shimizu, S.; Ando, Y.; Morioka, T.

1990-01-01

Plant maintenance is recently becoming important with the increase in the number of nuclear power stations and in plant operating time. Various kinds of requirements for plant maintenance, such as countermeasures for equipment degradation and saving maintenance costs while keeping up plant reliability and productivity, are proposed. For this purpose, plant maintenance programs should be improved based on equipment reliability estimated by field data. In order to meet these requirements, it is planned to develop an equipment maintenance management support system for nuclear power plants based on statistical analysis of equipment maintenance history data. The large difference between this proposed new method and current similar methods is to evaluate not only failure data but maintenance data, which includes normal termination data and some degree of degradation or functional disorder data for equipment and parts. So, it is possible to utilize these field data for improving maintenance schedules and to evaluate actual equipment and parts reliability under the current maintenance schedule. In the present paper, the authors show the objectives of this system, an outline of this system and its functions, and the basic technique for collecting and managing of maintenance history data on statistical analysis. It is shown, from the results of feasibility tests using simulation data of maintenance history, that this system has the ability to provide useful information for maintenance and the design enhancement

Comparative study of heuristics algorithms in solving flexible job shop scheduling problem with condition based maintenance

Directory of Open Access Journals (Sweden)

Yahong Zheng

2014-05-01

Full Text Available Purpose: This paper focuses on a classic optimization problem in operations research, the flexible job shop scheduling problem (FJSP, to discuss the method to deal with uncertainty in a manufacturing system.Design/methodology/approach: In this paper, condition based maintenance (CBM, a kind of preventive maintenance, is suggested to reduce unavailability of machines. Different to the simultaneous scheduling algorithm (SSA used in the previous article (Neale & Cameron,1979, an inserting algorithm (IA is applied, in which firstly a pre-schedule is obtained through heuristic algorithm and then maintenance tasks are inserted into the pre-schedule scheme.Findings: It is encouraging that a new better solution for an instance in benchmark of FJSP is obtained in this research. Moreover, factually SSA used in literature for solving normal FJSPPM (FJSP with PM is not suitable for the dynamic FJSPPM. Through application in the benchmark of normal FJSPPM, it is found that although IA obtains inferior results compared to SSA used in literature, it performs much better in executing speed.Originality/value: Different to traditional scheduling of FJSP, uncertainty of machines is taken into account, which increases the complexity of the problem. An inserting algorithm (IA is proposed to solve the dynamic scheduling problem. It is stated that the quality of the final result depends much on the quality of the pre-schedule obtained during the procedure of solving a normal FJSP. In order to find the best solution of FJSP, a comparative study of three heuristics is carried out, the integrated GA, ACO and ABC. In the comparative study, we find that GA performs best in the three heuristic algorithms. Meanwhile, a new better solution for an instance in benchmark of FJSP is obtained in this research.

Information-Based Maintenance Optimization with Focus on Predictive Maintenance (Informatiegebaseerde onderhoudsoptimalisatie met focus op predictief onderhoud)

OpenAIRE

Van Horenbeek, Adriaan

2013-01-01

This dissertation presents an information-based maintenance optimization methodology for physical assets; with focus on, but not limited to, predictive maintenance (PdM). The overall concept of information-based maintenance is that of updating maintenance decisions based on evolving knowledge of operation history and anticipated usage of the machinery, as well as the physics and dynamics of material degradation in critical machinery components. Within this concept, predictive maintenance is a...

Maintenance Staffing Standards for Zero-Based Budgeting.

Science.gov (United States)

Adams, Matthew C.; And Others

1998-01-01

Discusses school preventive maintenance and the variables associated with maintenance staffing standards that address a zero-based budgeting environment. Explores preventive-maintenance measurement for staffing requirements, defines staffing levels and job descriptions, and outlines the factors to consider when creating a maintenance program and…

Gym-based exercise was more costly compared with home-based exercise with telephone support when used as maintenance programs for adults with chronic health conditions: cost-effectiveness analysis of a randomised trial

Directory of Open Access Journals (Sweden)

Paul Jansons

2018-01-01

Registration: ACTRN12610001035011. [Jansons P, Robins L, O’Brien L, Haines T (2018 Gym-based exercise was more costly compared with home-based exercise with telephone support when used as maintenance programs for adults with chronic health conditions: cost-effectiveness analysis of a randomised trial. Journal of Physiotherapy 64: 48–54

Performance-based maintenance of gas turbines for reliable control of degraded power systems

Science.gov (United States)

Mo, Huadong; Sansavini, Giovanni; Xie, Min

2018-03-01

Maintenance actions are necessary for ensuring proper operations of control systems under component degradation. However, current condition-based maintenance (CBM) models based on component health indices are not suitable for degraded control systems. Indeed, failures of control systems are only determined by the controller outputs, and the feedback mechanism compensates the control performance loss caused by the component deterioration. Thus, control systems may still operate normally even if the component health indices exceed failure thresholds. This work investigates the CBM model of control systems and employs the reduced control performance as a direct degradation measure for deciding maintenance activities. The reduced control performance depends on the underlying component degradation modelled as a Wiener process and the feedback mechanism. To this aim, the controller features are quantified by developing a dynamic and stochastic control block diagram-based simulation model, consisting of the degraded components and the control mechanism. At each inspection, the system receives a maintenance action if the control performance deterioration exceeds its preventive-maintenance or failure thresholds. Inspired by realistic cases, the component degradation model considers random start time and unit-to-unit variability. The cost analysis of maintenance model is conducted via Monte Carlo simulation. Optimal maintenance strategies are investigated to minimize the expected maintenance costs, which is a direct consequence of the control performance. The proposed framework is able to design preventive maintenance actions on a gas power plant, to ensuring required load frequency control performance against a sudden load increase. The optimization results identify the trade-off between system downtime and maintenance costs as a function of preventive maintenance thresholds and inspection frequency. Finally, the control performance-based maintenance model can reduce

The machines maintenance conditions assessment in the plastic industry

Directory of Open Access Journals (Sweden)

Stanisław Borkowski

2015-12-01

Full Text Available The purpose, methodology, main findings, the originality of the subject area (research, way of using. The main research analysis purpose is a presentation, an assessment and an interpretation of the research findings on the machines maintenance conditions in the plastic industry. The research analysis was carried out with applying Technology ABC method and TPM coefficients calculations connected with Techno pak machine components maintenance. The research was carried out in the chosen manufacturing enterprise of the plastic industry. Research findings interpretation results have been introduced in the analyzed enterprise in the form of the manufacturing processes improvement.

Component-Based Data-Driven Predictive Maintenance to Reduce Unscheduled Maintenance Events

NARCIS (Netherlands)

Verhagen, W.J.C.; Curran, R.; de Boer, L.W.M.; Chen, C.H.; Trappey, A.C.; Peruzzini, M.; Stjepandić, J.; Wognum, N.

2017-01-01

Costs associated with unscheduled and preventive maintenance can contribute significantly to an airline's expenditure. Reliability analysis can help to identify and plan for maintenance events. Reliability analysis in industry is often limited to statistically based

Condition monitoring and maintenance of nuclear power plant concrete structures

International Nuclear Information System (INIS)

Orr, R.; Prasad, N.

1988-01-01

Nuclear power plant concrete structures are potentially subject to deterioration due to several environmental conditions, including weather exposure, ground water exposure, and sustained high temperature and radiation levels. The nuclear power plant are generally licensed for a term of 40 years. In order to maximize the return from the existing plants, feasibility studies are in progress for continued operation of many of these plants beyond the original licensed life span. This paper describes a study that was performed with an objective to define appropriate condition monitoring and maintenance procedures. A timely implementation of a condition monitoring and maintenance program would provide a valuable database and would provide justification for extension of the plant's design life. The study included concrete structures such as the containment buildings, interior structures, basemats, intake structures and cooling towers. Age-related deterioration at several operating power plants was surveyed and the potential degradation mechanisms have been identified

A comprehensive approach to RCM-based preventive maintenance program development

International Nuclear Information System (INIS)

Hall, B.E.; Davis, T.; Pennington, A.J.

1988-01-01

In late 1986, Public Service Electric and Gas Company (PSE ampersand G) concluded that to support its vision and strategic planning it would be necessary to develop a consistent approach to maintenance for all nuclear units at the artificial island. General Physics Corporation was selected to lead a consultant team to support full-scale development of a preventive maintenance (PM) program for Salem and Hope Creek generating stations based on a reliability-centered maintenance (RCM) approach. RCM was selected because it represents a systematic approach to developing a PM program that provides a logical, consistent, and traceable methodology and produces a well-documented engineering basis for the program. Early in 1987, primary objectives for the PM program were defined. The Phase I tasks addressed key programmatic areas such as maintenance philosophy, procedures, condition monitoring, performance trending, equipment failure data base, ogranization, PM program effectiveness evaluation, RCM process, reliability/availability modeling, information management, training, spare parts, software/hardware, and commitments. Phase I of the PM program development project was completed in January 1988. Highlights of the Phase I work and the PM program manual are described

Cost savings from performance-based maintenance contracting

NARCIS (Netherlands)

Straub, A.

2009-01-01

New procurement approaches combined with performance-based building approaches should reduce costs, but empirical qualitative and quantitative studies are lacking. Performance-based maintenance contracts give maintenance suppliers incentives to improve their way of working. Innovative,

A STEPPING STONE TOWARDS KNOWLEDGE BASED MAINTENANCE

Directory of Open Access Journals (Sweden)

G. Waeyenbergh

2012-01-01

Full Text Available Maintenance decision making becomes more and more a management concern. Some decades ago, maintenance was still often considered as an unavoidable side effect of production. The perception of maintenance has evolved considerably. One of the current issues is the maintenance concept, being the mix of maintenance interventions and the general framework for determining this mix. In this paper we describe a modular framework, called Knowledge Based Maintenance, for developing a customised maintenance concept. After describing the general framework and its decision support use, some case experiences are given. This experience covers some elements of the proposed framework.

Development the conceptual design of Knowledge Based System for Integrated Maintenance Strategy and Operation

Science.gov (United States)

Milana; Khan, M. K.; Munive, J. E.

2014-07-01

The importance of maintenance has escalated significantly by the increasing of automation in manufacturing process. This condition switches traditional maintenance perspective of inevitable cost into the business competitive driver. Consequently, maintenance strategy and operation decision needs to be synchronized to business and manufacturing concerns. This paper shows the development of conceptual design of Knowledge Based System for Integrated Maintenance Strategy and Operation (KBIMSO). The framework of KBIMSO is elaborated to show the process of how the KBIMSO works to reach the maintenance decision. By considering the multi-criteria of maintenance decision making, the KB system embedded with GAP and AHP to support integrated maintenance strategy and operation which is novel in this area. The KBIMSO is useful to review the existing maintenance system and give reasonable recommendation of maintenance decisions in respect to business and manufacturing perspective.

Development the conceptual design of Knowledge Based System for Integrated Maintenance Strategy and Operation

International Nuclear Information System (INIS)

Milana; Khan, M K; Munive, J E

2014-01-01

The importance of maintenance has escalated significantly by the increasing of automation in manufacturing process. This condition switches traditional maintenance perspective of inevitable cost into the business competitive driver. Consequently, maintenance strategy and operation decision needs to be synchronized to business and manufacturing concerns. This paper shows the development of conceptual design of Knowledge Based System for Integrated Maintenance Strategy and Operation (KBIMSO). The framework of KBIMSO is elaborated to show the process of how the KBIMSO works to reach the maintenance decision. By considering the multi-criteria of maintenance decision making, the KB system embedded with GAP and AHP to support integrated maintenance strategy and operation which is novel in this area. The KBIMSO is useful to review the existing maintenance system and give reasonable recommendation of maintenance decisions in respect to business and manufacturing perspective

Maintenance evaluation using risk based criteria

International Nuclear Information System (INIS)

Torres Valle, A.

1996-01-01

The maintenance evaluation is currently performed by using economic and, in some case, technical equipment failure criteria, however this is done to a specific equipment level. In general, when statistics are used the analysis for maintenance optimization are made isolated and whit a post mortem character; The integration provided by mean of Probabilistic Safety assessment (PSA) together with the possibilities of its applications, allow for evaluation of maintenance on the basis of broader scope criteria in regard to those traditionally used. The evaluate maintenance using risk based criteria, is necessary to follow a dynamic and systematic approach, in studying the maintenance strategy, to allow for updating the initial probabilistic models, for including operational changes that often take place during operation of complex facilities. This paper proposes a dynamic evaluation system of maintenance task. The system is illustrated by means of a practical example

Pavement condition assessment to forecast maintenance program on JKR state roads in Petaling district

Science.gov (United States)

Hamsan, R.; Hafiz, H.; Azlan, A.; Keprawi, M. F.; Malik, A. K. A.; Adamuddin, A.; Abdullah, A. H.; Shafie, A. M.

2018-02-01

This research allows local authorities to project road maintenance in term of activities and financial expenditure through pavement condition assessment and then Highway Development and Management (HDM-4) analysis. Current form of road maintenance carried out by local authority is on reactive manner where corrective actions were taken based on reports recorded. Some went unrecorded hence causing prolonged damages. This causes the local authority unable to project the required cost to maintain the roads. This affects the socio-economy of the surrounding routes. Hence, it is seen, as preventive maintenance of the roads will provide more feasible option in term of work force and finance to the local authority. To overcome this issue, a preventive model was introduced. This was done through pavement condition assessment (PCA) where analysis was done through HDM-4. Nondestructive test and destructive test were conducted in order to provide an indicator to the road's health. This were then analyzed in HDM-4 where the result was benchmarked with maintenance standard. The scope of this research is set to PCA where DT and NDT were performed on the routes of Petaling and the output is analyzed in HDM-4. The result of this research provides a 10 years forecast maintenance budget in maintaining the roads in Petaling. This allows the local authority to perform good practice in term of maintaining the roads while at the same time helps them in forecasting their budget for the upcoming years. This research will have a strong impact on the local socio-economy as well as local road user confidence towards the authority over good practices. This research can be further expanded to other type of roads as well as highway bridges.

Using the system maintenance datastore to characterize lifetime maintenance for PLiM

International Nuclear Information System (INIS)

Watson, P.; Dam, R.; Nickerson, J.

2004-01-01

A comprehensive Plant Life Management (PLiM) program involves evaluating a large amount of information. For any plant, there are numerous maintenance, surveillance and inspection programs for the important systems, structures and components. There is extensive industry experience on component failure modes, degradation mechanisms and recommended maintenance practices. This information forms the basis of the aging assessment work, through which improvements to these plant programs are identified. AECL has developed several tools to manage the quantities of information required in aging assessment studies, such as the SYSTMS (SYtematic approach for the development of STrategy for Maintenance and Surveillance) tool and the System Maintenance Datastore (SMD). The SMD has been developed to serve as a hub to a Systematic based Adaptive Maintenance Program (SAMP), by storing maintenance resource requirements for recommended maintenance tasks for use by the other processes in a SAMP. The SMD can be used to (a) quantify the savings or cost of optimising a maintenance program, (b) characterize and understand long term trends in condition-based maintenance due to component aging, (c) quantify the resource savings due to optimum timing of component replacement or general plant refurbishment, and (d) provide aging assessment cost information for input to plant asset evaluation. The SMD contains data for regular maintenance program tasks, plant condition assessment recommendations, and equipment refurbishment costs. A prototype SMD has been developed with data tables populated with information from operating CANDU stations. The SMD is now available to be used either with a SYSTMS evaluation or with a plant's database of maintenance tasks. (author)

A Real-Time Quantitative Condition Alerting and Analysis Support System for Aircraft Maintenance, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Financial constraints and the need for improved operational efficiency are requiring airlines to emphasize "on-condition" maintenance over scheduled maintenance...

A knowledge-based assistant for valve maintenance planning

International Nuclear Information System (INIS)

Winter, M.J.; Danofsky, R.A.; Spinrad, B.I.; Howard, K.

1987-01-01

A knowledge-based program is being developed to assist engineers in maintenance planning for safety related, motor-operated valves at a boiling water reactor. The purpose of this project is to develop the general framework for a prototype system that demonstrates the capabilities for diagnosing valve symptoms and prescribing corrective maintenance, completing a portion of the Corrective Maintenance Action Request (CMAR) form which must be prepared for each job, and managing an interactive valve data base. Minimizing user input and providing output in a form that is familiar to the maintenance planning engineer are important goals for the program. This paper describes the present features of the valve maintenance advisory system which is currently being tested

A cost effective degradation-based maintenance strategy under imperfect repair

International Nuclear Information System (INIS)

Wu, Fan; Niknam, Seyed A.; Kobza, John E.

2015-01-01

An optimization model is developed to minimize the total cost of imperfect degradation-based maintenance by determining an optimal interval of condition monitoring and the degradation level after imperfect preventive repairs. The decision model is based on a novel cost model that considers functional relationship between the expected degradation reduction and the cost of preventive repairs. The decision model is applied to simulated vibration signals with a variety of specifications of cost values and degradation model parameters. This study has initiated a new area for the research of cost effective maintenance strategies. The results clearly indicate the significance of the proposed model and the decision variables under the objective of minimal cost. For instance, the results indicate direct relationship between the optimal length of monitoring interval and the monitoring cost. However, longer monitoring interval increases the risk of failure, and therefore, more degradation reduction is needed. By increasing the slope of cumulative degradation, the cost effective strategy advocates taking more frequent monitoring. The optimal degradation level after each preventive repair is not so sensitive to the change in the degradation slope due to the uncertainty associated with degradation patterns. - Highlights: • Discuss the relationship of degradation reduction and maintenance cost. • Determine the optimal interval of condition monitoring with minimal cost. • Identify the optimal degradation level after imperfect preventive repairs. • Discuss the effects of change in the slope of cumulative degradation.

Failure and Maintenance Analysis Using Web-Based Reliability Database System

International Nuclear Information System (INIS)

Hwang, Seok Won; Kim, Myoung Su; Seong, Ki Yeoul; Na, Jang Hwan; Jerng, Dong Wook

2007-01-01

Korea Hydro and Nuclear Power Company has lunched the development of a database system for PSA and Maintenance Rule implementation. It focuses on the easy processing of raw data into a credible and useful database for the risk-informed environment of nuclear power plant operation and maintenance. Even though KHNP had recently completed the PSA for all domestic NPPs as a requirement of the severe accident mitigation strategy, the component failure data were only gathered as a means of quantification purposes for the relevant project. So, the data were not efficient enough for the Living PSA or other generic purposes. Another reason to build a real time database is for the newly adopted Maintenance Rule, which requests the utility to continuously monitor the plant risk based on its operation and maintenance performance. Furthermore, as one of the pre-condition for the Risk Informed Regulation and Application, the nuclear regulatory agency of Korea requests the development and management of domestic database system. KHNP is stacking up data of operation and maintenance on the Enterprise Resource Planning (ERP) system since its first opening on July, 2003. But, so far a systematic review has not been performed to apply the component failure and maintenance history for PSA and other reliability analysis. The data stored in PUMAS before the ERP system is introduced also need to be converted and managed into the new database structure and methodology. This reliability database system is a web-based interface on a UNIX server with Oracle relational database. It is designed to be applicable for all domestic NPPs with a common database structure and the web interfaces, therefore additional program development would not be necessary for data acquisition and processing in the near future. Categorization standards for systems and components have been implemented to analyze all domestic NPPs. For example, SysCode (for a system code) and CpCode (for a component code) were newly

Imperfect Preventive Maintenance Model Study Based On Reliability Limitation

Directory of Open Access Journals (Sweden)

Zhou Qian

2016-01-01

Full Text Available Effective maintenance is crucial for equipment performance in industry. Imperfect maintenance conform to actual failure process. Taking the dynamic preventive maintenance cost into account, the preventive maintenance model was constructed by using age reduction factor. The model regards the minimization of repair cost rate as final target. It use allowed smallest reliability as the replacement condition. Equipment life was assumed to follow two parameters Weibull distribution since it was one of the most commonly adopted distributions to fit cumulative failure problems. Eventually the example verifies the rationality and benefits of the model.

Reliability-based performance simulation for optimized pavement maintenance

International Nuclear Information System (INIS)

Chou, Jui-Sheng; Le, Thanh-Son

2011-01-01

Roadway pavement maintenance is essential for driver safety and highway infrastructure efficiency. However, regular preventive maintenance and rehabilitation (M and R) activities are extremely costly. Unfortunately, the funds available for the M and R of highway pavement are often given lower priority compared to other national development policies, therefore, available funds must be allocated wisely. Maintenance strategies are typically implemented by optimizing only the cost whilst the reliability of facility performance is neglected. This study proposes a novel algorithm using multi-objective particle swarm optimization (MOPSO) technique to evaluate the cost-reliability tradeoff in a flexible maintenance strategy based on non-dominant solutions. Moreover, a probabilistic model for regression parameters is employed to assess reliability-based performance. A numerical example of a highway pavement project is illustrated to demonstrate the efficacy of the proposed MOPSO algorithms. The analytical results show that the proposed approach can help decision makers to optimize roadway maintenance plans. - Highlights: →A novel algorithm using multi-objective particle swarm optimization technique. → Evaluation of the cost-reliability tradeoff in a flexible maintenance strategy. → A probabilistic model for regression parameters is employed to assess reliability-based performance. → The proposed approach can help decision makers to optimize roadway maintenance plans.

Reliability-based performance simulation for optimized pavement maintenance

Energy Technology Data Exchange (ETDEWEB)

Chou, Jui-Sheng, E-mail: jschou@mail.ntust.edu.tw [Department of Construction Engineering, National Taiwan University of Science and Technology (Taiwan Tech), 43 Sec. 4, Keelung Rd., Taipei 106, Taiwan (China); Le, Thanh-Son [Department of Construction Engineering, National Taiwan University of Science and Technology (Taiwan Tech), 43 Sec. 4, Keelung Rd., Taipei 106, Taiwan (China)

2011-10-15

Roadway pavement maintenance is essential for driver safety and highway infrastructure efficiency. However, regular preventive maintenance and rehabilitation (M and R) activities are extremely costly. Unfortunately, the funds available for the M and R of highway pavement are often given lower priority compared to other national development policies, therefore, available funds must be allocated wisely. Maintenance strategies are typically implemented by optimizing only the cost whilst the reliability of facility performance is neglected. This study proposes a novel algorithm using multi-objective particle swarm optimization (MOPSO) technique to evaluate the cost-reliability tradeoff in a flexible maintenance strategy based on non-dominant solutions. Moreover, a probabilistic model for regression parameters is employed to assess reliability-based performance. A numerical example of a highway pavement project is illustrated to demonstrate the efficacy of the proposed MOPSO algorithms. The analytical results show that the proposed approach can help decision makers to optimize roadway maintenance plans. - Highlights: > A novel algorithm using multi-objective particle swarm optimization technique. > Evaluation of the cost-reliability tradeoff in a flexible maintenance strategy. > A probabilistic model for regression parameters is employed to assess reliability-based performance. > The proposed approach can help decision makers to optimize roadway maintenance plans.

Conditions of job performance quality during nuclear reactor maintenance

International Nuclear Information System (INIS)

Babos, K.; Takacs, J.

1991-01-01

The education and training programs of the maintenance personnel at the Paks Nuclear Power Plant, Hungary are described. In addition to well trained personnel, the conditions of job quality involves the preparation of job by proper check lists and availability of documentation, and the inspection and checking of the accomplishment of job tasks. Such an inspection procedure is proposed. (R.P.) 2 figs

Regulatory oversight of maintenance activities at nuclear power plants

International Nuclear Information System (INIS)

Pape, M.

1997-01-01

Regulation of nuclear safety in the UK is based on monitoring of compliance with licence conditions. This paper discusses legislation aspects, license conditions, license requirements for maintenance and maintenance activities in the UK. It also addresses the regulator utility interaction, the regulatory inspection of maintenance and the trends in maintenance. (author)

The Issues of Track Maintenance Management in Indonesia (Based on Study of the British Railways

Directory of Open Access Journals (Sweden)

Tetria Yunik Dewi Pamungkas

2017-01-01

Full Text Available It is believed that there is merit in researching how the management of track maintenance is organized in the United Kingdom, in particular by Network Rail, and then evaluating how this can be applied to the benefit of Indonesian Railways. The purpose of this research was expected to provide recommendations for management improvement of track maintenance by researching the track maintenance management system in Network Rail. This research study is based on secondary data. The analysis was conducted by using comparison method which compares the British Railways management and Indonesia railway management related to track maintenance management. The track maintenance management system was studied by using Network Rail. The results were compared with track maintenance management system in Indonesia. The comparison will provide the data differences that evaluated so the problem can be identified. The final result of this analysis was the identification of problems and improvisation that can be done for the development of track maintenance management in Indonesia. Several management issues have been mapped to several groups: finance management, structure organization, and asset management. From the problems that have been mapped, some improvements are recommended as monopolist authority restriction, maintenance system contract extension, re-structuring organization hierarchy, business plan consideration, track monitoring strategy arrangement, and condition based maintenance strategy adoption.

Risk-based and maintenance systems for steam turbines

International Nuclear Information System (INIS)

Fujiyama, K.; Nagai, S.; Akikuni, Y.; Fujiwara, T.; Furuya, K.; Matsumoto, S.; Takagi, K.; Kawabata, T.

2003-01-01

The risk-based maintenance (RBM) system has been developed for steam turbine plants coupled with the quick inspection systems. The RBM system utilizes the field failure and inspection database accumulated over 30 years. The failure modes are determined for each component of steam turbines and the failure scenarios are described as event trees. The probability of failure is expressed in the form of unreliability functions of operation hours or start-up cycles through the cumulative hazard function method. The posterior unreliability is derived from the field data analysis according to the inspection information. Quick inspection can be conducted using air-cooled borescope and heat resistant ultrasonic sensors even if the turbine is not cooled down sufficiently. Another inspection information comes from degradation and damage measurement. The probabilistic life assessment using structural analysis and statistical material properties, the latter is estimated from hardness measurement, replica observation and embrittlement measurement. The risk function is calculated as the sum product of unreliability functions and expected monetary loss as the consequence of failure along event trees. The optimum maintenance plan is determined among simulated scenarios described through component breakdown trees, life cycle event trees and risk functions. Those methods are effective for total condition assessment and economical maintenance for operating plants. (orig.)

A dynamic predictive maintenance policy for complex multi-component systems

International Nuclear Information System (INIS)

Van Horenbeek, Adriaan; Pintelon, Liliane

2013-01-01

The use of prognostic methods in maintenance in order to predict remaining useful life is receiving more attention over the past years. The use of these techniques in maintenance decision making and optimization in multi-component systems is however a still underexplored area. The objective of this paper is to optimally plan maintenance for a multi-component system based on prognostic/predictive information while considering different component dependencies (i.e. economic, structural and stochastic dependence). Consequently, this paper presents a dynamic predictive maintenance policy for multi-component systems that minimizes the long-term mean maintenance cost per unit time. The proposed maintenance policy is a dynamic method as the maintenance schedule is updated when new information on the degradation and remaining useful life of components becomes available. The performance, regarding the objective of minimal long-term mean cost per unit time, of the developed dynamic predictive maintenance policy is compared to five other conventional maintenance policies, these are: block-based maintenance, age-based maintenance, age-based maintenance with grouping, inspection condition-based maintenance and continuous condition-based maintenance. The ability of the predictive maintenance policy to react to changing component deterioration and dependencies within a multi-component system is quantified and the results show significant cost savings

Using systematic aging assessments to improve effectiveness of plant maintenance programs

International Nuclear Information System (INIS)

Watson, P.; Yang, J.X.; Dam, R.F.; Nickerson, J.H.

2003-01-01

Nuclear plant equipment aging assessment studies provided by AECL include life assessments, condition assessments or systematic assessments of maintenance. AECL has developed several tools to apply the results of aging assessment studies to improve the effectiveness of actual plant maintenance programs. The Systematic Assessment of Maintenance and the SYSTMS tool generate maintenance tasks for a system. The System Maintenance Datastore tool assesses the maintenance resources on a system basis, and can thus quantify the savings realized by optimizing the maintenance program. Long term trends in condition-based maintenance due to component aging can be predicted, and resource savings due to optimum timing of component replacement or general plant refurbishment can be quantified. The System based Adaptive Maintenance Process ensures the maintenance program is continually updated to reflect the latest plant equipment condition and maintenance strategy information. (author)

Reliability analysis and risk-based methods for planning of operation & maintenance of offshore wind turbines

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard

2017-01-01

for extreme and fatigue limit states are presented. Operation & Maintenance planning often follows corrective and preventive strategies based on information from condition monitoring and structural health monitoring systems. A reliability- and risk-based approach is presented where a life-cycle approach...

A decision-making framework to integrate maintenance contract conditions with critical spares management

International Nuclear Information System (INIS)

Godoy, David R.; Pascual, Rodrigo; Knights, Peter

2014-01-01

Maintenance outsourcing is a strategic driver for asset intensive industries pursuing to enhance supply chain performance. Spare parts management plays a relevant role in this premise since its significant impact on equipment availability, and hence on business success. Designing critical spares policies might therefore seriously affect maintenance contracts profitability, yet service receivers and external providers traditionally attempt to benefit separately. To coordinate both chain parties, we investigated whether the spare components pool should be managed in-house or contracted out. This paper provides a decision-making framework to efficiently integrate contractual conditions with critical spares stockholding. Using an imperfect maintenance strategy over a finite horizon, the scheme maximizes chain returns whilst evaluating the impact of an additional part to stock. As result, an original joint value – preventive interval and stock level – sets the optimal agreement to profitably allocate the components pool within the service contract. Subsidization bonuses on preventive interventions and pooling costs are also estimated to induce the service provider to adjust its policy when needed. The proposed contractual conditions motivate stakeholders to continuously improve maintenance performance and supply practices, thus obtaining higher joint benefits

Reliability and risk-based planning of operation and maintenance of offshore wind turbines

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard; Florian, Mihai; Berzonskis, Arvydas

2016-01-01

costly (and safe), and it is important to include in the reliability assessment the information obtained during operation (from condition monitoring and inspections) and the maintenance performed (incl. repairs and replacements). The paper presents a risk-based approach for optimal planning of Operation...

Virtual maintenance technology for reactor system based on PPR technology

International Nuclear Information System (INIS)

Wu Yaxiang; Ma Baiyong

2009-01-01

Based on the Product, Process and Resources (PPR) technology, the establishing technology of virtual maintenance environment for the reactor system and the process structure tree for virtual maintenance is studied, and the flow for the maintainability design and simulation for reactor system is put forward. Based on the subsection simulation of maintenance process and layered design of maintenance actions, the leveled structure of the reactor system virtual maintenance task is studied. The relation for the data of product, process and resource is described by Plan Evaluation and Review Technology (PERT) diagram to define the maintenance operation. (authors)

Maintenance for the Millennium: Another Approach

International Nuclear Information System (INIS)

Sculthorpe, Barruy R.

2002-01-01

Nuclear units nationwide are struggling to increase plant reliability and availability while at the same time reduce their operating and maintenance costs. Some very costly investments have been made in programs such as Reliability Centered Maintenance [RCM]. Florida Power and Light's approach at the St. Lucie Nuclear Plant has taken a slightly different approach. Building on our knowledge of the RCM process and an already existing 'World Class' Predictive Maintenance Program, a 'Condition-Based' Maintenance Program that takes advantage of the RCM philosophy and our toolbox full of advanced and highly successful predictive maintenance technologies. These tools currently consist of vibration analysis, lubricant analysis (both physical property and wear metals analysis, thermographic analysis, motor current signature analysis, tribology and process parameter trending. All employed with the intent to evaluate a machines health. This machine health check allows the forecasting of future preventative maintenance [PM's] tasks and the revision of existing PM's to maximize machine performance and eliminate 'no-value-added' maintenance activities/costs. Within the last year, the Condition-Based Maintenance Program has produced a cost saving of approximately $1.5 million dollars. As the program matures, these cost savings will accumulate well into the millennium. (authors)

A Wavelet Bicoherence-Based Quadratic Nonlinearity Feature for Translational Axis Condition Monitoring

Directory of Open Access Journals (Sweden)

Yong Li

2014-01-01

Full Text Available The translational axis is one of the most important subsystems in modern machine tools, as its degradation may result in the loss of the product qualification and lower the control precision. Condition-based maintenance (CBM has been considered as one of the advanced maintenance schemes to achieve effective, reliable and cost-effective operation of machine systems, however, current vibration-based maintenance schemes cannot be employed directly in the translational axis system, due to its complex structure and the inefficiency of commonly used condition monitoring features. In this paper, a wavelet bicoherence-based quadratic nonlinearity feature is proposed for translational axis condition monitoring by using the torque signature of the drive servomotor. Firstly, the quadratic nonlinearity of the servomotor torque signature is discussed, and then, a biphase randomization wavelet bicoherence is introduced for its quadratic nonlinear detection. On this basis, a quadratic nonlinearity feature is proposed for condition monitoring of the translational axis. The properties of the proposed quadratic nonlinearity feature are investigated by simulations. Subsequently, this feature is applied to the real-world servomotor torque data collected from the X-axis on a high precision vertical machining centre. All the results show that the performance of the proposed feature is much better than that of original condition monitoring features.

Optimization of maintenance programme at Daya Bay Nuclear Power Station based on RCM analysis results

International Nuclear Information System (INIS)

Liu Min

2003-01-01

This paper begins with an introduction to Guangdong Daya Bay Nuclear Power Station (GNPS) and gives a simple introduction to the operations and maintenance documentation system at GNPS. It then will review the maintenance program guidelines base and the associated problems prior to the application of reliability centered maintenance (RCM). How RCM was implemented at GNPS, how the results of RCM analysis were used to optimize the maintenance program and test program, and what is the interface between RCM and the existing maintenance program will be shown. Next, it will show the successful implementation of RCM at GNPS resulted in the following changes: A new understanding of equipment failure challenges operations and maintenance beliefs, maintenance concepts undergo a large change, maintenance program and periodic testing program are continuously modified and optimized, new on-condition maintenance technologies are introduced, non-productive scheduled overhauls are discarded, maintenance costs are effectively controlled, maintenance appropriateness has improved, management of hidden failures is more effective and timely. It will show the benefit of greater equipment reliability brought about by all of these changes, which in turn increases the reliability and safety of the entire power station. (author)

Risk-Based Operation and Maintenance of Offshore Wind Turbines

DEFF Research Database (Denmark)

Nielsen, Jannie Sønderkær

For offshore wind turbines, maintenance costs are substantial due to a large number of component failures. In addition to the repair costs, equipment costs and lost production costs are large due to limited accessibility to the turbines. In order to reduce the costs, preventive methods can be used......, but presently maintenance is not planned using advanced methods taking all available information into account in a consistent manner. Maintenance decisions can be made based on risk-based methods, where the total expected life cycle costs are minimized. Methods have been developed for assessing the corrective...... maintenance costs, and many studies have also been published for preventive maintenance. However, an important part is the modeling of the relationship between maintenance and reliability, which is typically not modeled in a consistent way. Therefore, the methods cannot be used directly for optimal...

Design and evaluation of augmented reality for nuclear power plant maintenance based on Cognitive activity analysis

International Nuclear Information System (INIS)

Koo, Jwa Jin

2008-02-01

The goals of maintenance in nuclear power plants (NPPs) are to reduce the number of plant shutdowns, to decrease the shutdown time, to minimize the maintenance costs, and to improve nuclear safety. Furthermore, it is difficult for maintenance personnel to conduct work in NPPs due to the complexity of NPPs, safety issues and time constraints. Human errors should be prevented to achieve maintenance goals in NPPs. Therefore, it is necessary to improve working conditions by introducing support systems. Augmented Reality (AR) has the potential to assist with maintenance tasks and make maintenance personnel concentrate on the tasks, which will then the reduced human error and improve human performance. The working procedure for AR systems was designed based on the characteristics of cognitive activity, and an experiment was conducted to estimate the effectiveness of AR. The results indicated that a well-designed working procedure for AR systems was more effective than a conventional paper-based working procedure. In addition, participants made fewer errors using the designed working procedure. AR systems as maintenance support systems are beneficial technology that can improve maintenance performance by reducing cognitive loads and unnecessary movements. An AR application can be attractive and effective at supporting maintenance task

Review on the Pavement-repairing Measures as a Condition for the Choice of Road-Maintenance Strategy

Directory of Open Access Journals (Sweden)

Nedevska Ivana

2017-01-01

Full Text Available The road-maintenance strategies vary from one country to another, and even between the road management authorities within a one single country. It is not surprising, as there is not best maintenance method, nor a universal set of strategies that can be applied equally everywhere. Generally, there are strategies acceptable in certain conditions, but the factors influencing the selection process are diverse and very complex. This paper will present a review of the various measures that can be applied on the roads, which is certainly the basic condition of selection of an appropriate maintenance strategy.

Geometric Process-Based Maintenance and Optimization Strategy for the Energy Storage Batteries

Directory of Open Access Journals (Sweden)

Yan Li

2016-01-01

Full Text Available Renewable energy is critical for improving energy structure and reducing environment pollution. But its strong fluctuation and randomness have a serious effect on the stability of the microgrid without the coordination of the energy storage batteries. The main factors that influence the development of the energy storage system are the lack of valid operation and maintenance management as well as the cost control. By analyzing the typical characteristics of the energy storage batteries in their life cycle, the geometric process-based model including the deteriorating system and the improving system is firstly built for describing the operation process, the preventive maintenance process, and the corrective maintenance process. In addition, this paper proposes an optimized management strategy, which aims to minimize the long-run average cost of the energy storage batteries by defining the time interval of the detection and preventive maintenance process as well as the optimal corrective maintenance times, subjected to the state of health and the reliability conditions. The simulation is taken under the built model by applying the proposed energy storage batteries’ optimized management strategy, which verifies the effectiveness and applicability of the management strategy, denoting its obvious practicality on the current application.

CANDU plant maintenance: Recent developments

International Nuclear Information System (INIS)

Charlebois, P.

2000-01-01

CANDU units have long been recognized for their exceptional safety and reliability. Continuing development in the maintenance area has played a key role in achieving this performance level. For over two decades, safety system availability has been monitored closely and system maintenance programs adjusted accordingly to maintain high levels of performance. But as the plants approach mid life in a more competitive environment and component aging becomes a concern, new methods and techniques are necessary. As a result, recent developments are moving the maintenance program largely from a corrective and preventive approach to predictive and condition based maintenance. The application of these techniques is also being extended to safety related systems. These recent developments include use of reliability centred methods to define system maintenance requirements and strategies. This approach has been implemented on a number of systems at Canadian CANDU plants with positive results. The pilot projects demonstrated that the overall maintenance effort remained relatively constant while the system performance improved. It was also possible to schedule some of the redundant component maintenance during plant operation without adverse impact on system availability. The probabilistic safety assessment was found to be useful in determining the safety implications of component outages. These new maintenance strategies are now making use of predictive and condition based maintenance techniques to anticipate equipment breakdown and schedule preventive maintenance as the need arises rather than time based. Some of these techniques include valve diagnostics, vibration monitoring, oil analysis, thermography. Of course, these tools and techniques must form part of an overall maintenance management system to ensure that maintenance becomes a living program. To facilitate this process and contain costs, new information technology tools are being introduced to provide system engineers

Framework for Risk-based Planning of Operation and Maintenance for Offshore Wind Turbines

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard

2009-01-01

, and to sequential optimal decision making on planning of OM taking into account new information. Deterioration mechanisms such as fatigue, corrosion, wear and erosion are associated with significant uncertainty. Observations of the degree of damage can increase the reliability of predictions, especially......For offshore wind turbines, costs to operation and maintenance (OM) are substantial. This paper describes a risk-based life cycle approach for optimal planning of OM. The approach is based on pre-posterior Bayesian decision theory, and can be used both to overall, initial planning of OM...... in connection with condition-based maintenance. The approach can be used for gearboxes, generators, fatigue cracks, corrosion, etc. This paper also describes how probabilistic indicators can be used to quantify indirect information about the damage state for critical components, e.g. gearboxes....

A Bayesian network based approach for integration of condition-based maintenance in strategic offshore wind farm O&M simulation models

DEFF Research Database (Denmark)

Nielsen, Jannie Sønderkær; Sørensen, John Dalsgaard; Sperstad, Iver Bakken

2018-01-01

In the overall decision problem regarding optimization of operation and maintenance (O&M) for offshore wind farms, there are many approaches for solving parts of the overall decision problem. Simulation-based strategy models accurately capture system effects related to logistics, but model...... to generate failures and CBM tasks. An example considering CBM for wind turbine blades demonstrates the feasibility of the approach....

Risk-Based Operation and Maintenance of Offshore Wind Turbines

DEFF Research Database (Denmark)

Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

2009-01-01

For offshore wind turbines costs to operation and maintenance are substantial. This paper describes a risk-based lifecycle approach for optimal planning of operation and maintenance. The approach is based on pre-posterior Bayesian decision theory. Deterioration mechanisms such as fatigue, corrosion...

Improving the TRIGA facility maintenance by predictive maintenance techniques

International Nuclear Information System (INIS)

Preda, M.; Sabau, C.; Barbalata, E.

1997-01-01

This work deals with the specific operation of equipment in radioactive environment or in conditions allowing radioactive contamination. The requirements of remote operation ensuring the operators' protection are presented. Also, the requirements of international standards issued by IAEA-Vienna are reviewed. The organizational withdraws of the maintenance activities, based on the standards and maintenance and repair directives still in force, are shown. It is emphasized the fact that this type of maintenance was adequate to a given level of technical development, characteristic for pre-computerized industry, but, at present, it is obsolete and uneconomic both in utilization and maintenance. Such a system constitutes already a burden hindering the efforts of maximizing the availability, maintenance, prolongation the service life of equipment and utilities, finally, of increasing the efficiency of complex installations. Moreover, the predictive maintenance techniques are strongly requested by the character of radioactive installations precluding the direct access in given zones (a potential risk of irradiation or radioactive contamination) of installations during operation. The results obtained by applying the predictive maintenance techniques in the operation of the double circuit irradiation loop, used in the TRIGA reactors, are presented

Upgrade of maintenance technologies of Nuclear Power Plants

International Nuclear Information System (INIS)

Kamada, Kazuaki

2005-01-01

In order to enhance long-term safe and stable operation of Ikata Nuclear Power Plants (NPPs) in more efficient way, maintenance technology upgrade project was started aiming at establishment of simplified and efficient self-maintenance system with affiliated companies. Maintenance technique and supervisor qualification system was introduced after improvement and reinforcement of personnel education and training. Reflecting investigation of maintenance activities of US NPPs and productivity improvement in other industries, preventive maintenance optimization project had been performed such as introduction of key performance indicator (KPI), new system incorporating reliability-centered maintenance (RCM) and condition-based maintenance (CBM), and on-line monitoring and maintenance (OLM) based on risk assessment. Enterprise asset management (EAM) to establish information data base and total productive maintenance (TPM) action for every personnel to participate in self-maintenance was also introduced. (T. Tanaka)

Value maximizing maintenance policies under general repair

International Nuclear Information System (INIS)

Marais, Karen B.

2013-01-01

One class of maintenance optimization problems considers the notion of general repair maintenance policies where systems are repaired or replaced on failure. In each case the optimality is based on minimizing the total maintenance cost of the system. These cost-centric optimizations ignore the value dimension of maintenance and can lead to maintenance strategies that do not maximize system value. This paper applies these ideas to the general repair optimization problem using a semi-Markov decision process, discounted cash flow techniques, and dynamic programming to identify the value-optimal actions for any given time and system condition. The impact of several parameters on maintenance strategy, such as operating cost and revenue, system failure characteristics, repair and replacement costs, and the planning time horizon, is explored. This approach provides a quantitative basis on which to base maintenance strategy decisions that contribute to system value. These decisions are different from those suggested by traditional cost-based approaches. The results show (1) how the optimal action for a given time and condition changes as replacement and repair costs change, and identifies the point at which these costs become too high for profitable system operation; (2) that for shorter planning horizons it is better to repair, since there is no time to reap the benefits of increased operating profit and reliability; (3) how the value-optimal maintenance policy is affected by the system's failure characteristics, and hence whether it is worthwhile to invest in higher reliability; and (4) the impact of the repair level on the optimal maintenance policy. -- Highlights: •Provides a quantitative basis for maintenance strategy decisions that contribute to system value. •Shows how the optimal action for a given condition changes as replacement and repair costs change. •Shows how the optimal policy is affected by the system's failure characteristics. •Shows when it is

Risk-based inspection and maintenance systems for steam turbines

International Nuclear Information System (INIS)

Fujiyama, Kazunari; Nagai, Satoshi; Akikuni, Yasunari; Fujiwara, Toshihiro; Furuya, Kenichiro; Matsumoto, Shigeru; Takagi, Kentaro; Kawabata, Taro

2004-01-01

The risk-based maintenance (RBM) system has been developed for steam turbine plants coupled with the quick inspection systems. The RBM system utilizes the field failure and inspection database accumulated over 30 years. The failure modes are determined for each component of steam turbines and the failure scenarios are described as event trees. The probability of failure is expressed in the form of unreliability functions of operation hours or start-up cycles through the cumulative hazard function method. The posterior unreliability is derived from the field data analysis according to the inspection information. Quick inspection can be conducted using air-cooled borescope and heat resistant ultrasonic sensors even if the turbine is not cooled down sufficiently. Another inspection information comes from degradation and damage measurement. The probabilistic life assessment using structural analysis and statistical material properties, the latter is estimated from hardness measurement, replica observation and embrittlement measurement. The risk function is calculated as the sum product of unreliability functions and expected monetary loss as the consequence of failure along event trees. The optimum maintenance plan is determined among simulated scenarios described through component breakdown trees, life cycle event trees and risk functions. Those methods are effective for total condition assessment and economical maintenance for operating plants

Optimizing block-based maintenance under random machine usage

NARCIS (Netherlands)

de Jonge, Bram; Jakobsons, Edgars

Existing studies on maintenance optimization generally assume that machines are either used continuously, or that times until failure do not depend on the actual usage. In practice, however, these assumptions are often not realistic. In this paper, we consider block-based maintenance optimization

The-Abstraction-Hierarchy-based Mobile PC Display Design for NPP Maintenance

International Nuclear Information System (INIS)

Kim, In; Kim, Bo Gyung; Seong, Poong Hyun; Ha, Jun Su

2010-01-01

Recently, the importance of effective maintenance in nuclear power plants (NPPs) has been emphasized and research into effective maintenance by adopting mobile maintenance aids (MMAs) have been attempted. For improved and effective use of an MMA display design method based on abstraction hierarchy (AH) is proposed and its design considerations are discussed in this study. Six levels of abstraction hierarchy are proposed in this paper to classify the maintenance information. By classifying and organizing maintenance information using AH, maintenance information can be used effectively by users with either high or low levels of expertise. When information classification has been finished, the information for MMA design is selected and designed. With the considerations of MMA design analysis and guidelines, AH-based MMA is designed for the maintenance tasks. An experiment is conducted using the AH-based MMA in order to estimate the effectiveness of the proposed method for the maintenance tasks and to identify design considerations to enhance the proposed MMAs. The result indicated that an AH-based manual was more effective than a conventional manual in terms of task completion time and number of errors. The workload for the AH-based manual was estimated less than the conventional manual for subjects with low level of expertise. As the level of expertise increases, subjects tended to follow more abstract information while the number of navigations decreased. It is believed that when mobile devices become pervasive in NPP maintenance fields, AH-model applied MMAs can be used as an effective maintenance supporting tool

A maintenance optimization model for mission-oriented systems based on Wiener degradation

International Nuclear Information System (INIS)

Guo, Chiming; Wang, Wenbin; Guo, Bo; Si, Xiaosheng

2013-01-01

Over the past few decades, condition-based maintenance (CBM) has attracted many researchers because of its effectiveness and practical significance. This paper deals with mission-oriented systems subject to gradual degradation modeled by a Wiener stochastic process within the context of CBM. For a mission-oriented system, the mission usually has constraints on availability/reliability, the opportunity for maintenance actions, and the monitoring type (continuous or discrete). Furthermore, in practice, a mission-oriented system may undertake some preventive maintenance (PM) and after such PM, the system may return to an intermediate state between an as-good-as new state and an as-bad-as old state, i.e., the PM is not perfect and only partially restores the system. However, very few CBM models integrated these mission constraints together with an imperfect nature of the PM into the course of optimizing the PM policy. This paper develops a model to optimize the PM policy in terms of the maintenance related cost jointly considering the mission constraints and the imperfect PM nature. A numerical example is presented to demonstrate the proposed model. The comparison with the simulated results and the sensitivity analysis show the usefulness of the optimization model for mission-oriented system maintenance presented in this paper.

On the Use of Time-Limited Information for Maintenance Decision Support: A Predictive Approach under Maintenance Constraints

Directory of Open Access Journals (Sweden)

E. Khoury

2013-01-01

Full Text Available This paper deals with a gradually deteriorating system operating under an uncertain environment whose state is only known on a finite rolling horizon. As such, the system is subject to constraints. Maintenance actions can only be planned at imposed times called maintenance opportunities that are available on a limited visibility horizon. This system can, for example, be a commercial vehicle with a monitored critical component that can be maintained only in some specific workshops. Based on the considered system, we aim to use the monitoring data and the time-limited information for maintenance decision support in order to reduce its costs. We propose two predictive maintenance policies based, respectively, on cost and reliability criteria. Classical age-based and condition-based policies are considered as benchmarks. The performance assessment shows the value of the different types of information and the best way to use them in maintenance decision making.

Development of a knowledge-based information management system for plant maintenance

International Nuclear Information System (INIS)

Yim, Hyung Sang; Park, Young Jae; Lee, Sang Min; Choi, Jae Boong; Kim, Young Jin; Roh, Eun Chul; Lee, Byung Ine

2003-01-01

Recently, the importance of Plant Maintenance(PM) was highly raised to provide efficient plant operation which highly affects the productivity. For this reason, a number of engineering methodologies, such as Risk-Based Inspection(RBI), Fitness For Service guidelines(FFS), Plant Lifecycle Management(PLM), have been applied to improve the plant operation efficiency. Also, a network-based business operation system, which is called ERP(Enterprise Resource Planning), has been introduced in the field of plant maintenance. However, there was no attempt to connect engineering methodologies to the ERP PM system. In this paper, a knowledge-based information system for the plant operation of steel making company has been proposed. This system, which is named as K-VRS(Knowledge-based Virtual Reality System), provides a connection between ERP plant maintenance module and knowledge-based engineering methodologies, and thus, enables network-based highly effective plant maintenance process. The developed system is expected to play a great role for more efficient and safer plant maintenance

Development of a knowledge-based information management system for plant maintenance

Energy Technology Data Exchange (ETDEWEB)

Yim, Hyung Sang; Park, Young Jae; Lee, Sang Min; Choi, Jae Boong; Kim, Young Jin [Sungkyunkwan Univ., Seoul (Korea, Republic of); Roh, Eun Chul; Lee, Byung Ine [Pohang Iron and Steel Company, Pohang (Korea, Republic of)

2003-07-01

Recently, the importance of Plant Maintenance(PM) was highly raised to provide efficient plant operation which highly affects the productivity. For this reason, a number of engineering methodologies, such as Risk-Based Inspection(RBI), Fitness For Service guidelines(FFS), Plant Lifecycle Management(PLM), have been applied to improve the plant operation efficiency. Also, a network-based business operation system, which is called ERP(Enterprise Resource Planning), has been introduced in the field of plant maintenance. However, there was no attempt to connect engineering methodologies to the ERP PM system. In this paper, a knowledge-based information system for the plant operation of steel making company has been proposed. This system, which is named as K-VRS(Knowledge-based Virtual Reality System), provides a connection between ERP plant maintenance module and knowledge-based engineering methodologies, and thus, enables network-based highly effective plant maintenance process. The developed system is expected to play a great role for more efficient and safer plant maintenance.

Energy-autonomous wireless vibration sensor for condition-based maintenance of machinery

NARCIS (Netherlands)

Wang, Z.; Bouwens, F.; Vullers, R.; Petré, F.; Devos, S.

2011-01-01

This paper addresses the development of an energy-autonomous wireless vibration sensor for condition-based monitoring of machinery. Such technology plays an increasingly important role in modern manufacturing industry. In this work, energy harvesting is realized by resorting to a custom designed

The International Coal Statistics Data Base program maintenance guide

International Nuclear Information System (INIS)

1991-06-01

The International Coal Statistics Data Base (ICSD) is a microcomputer-based system which contains information related to international coal trade. This includes coal production, consumption, imports and exports information. The ICSD is a secondary data base, meaning that information contained therein is derived entirely from other primary sources. It uses dBase III+ and Lotus 1-2-3 to locate, report and display data. The system is used for analysis in preparing the Annual Prospects for World Coal Trade (DOE/EIA-0363) publication. The ICSD system is menu driven and also permits the user who is familiar with dBase and Lotus operations to leave the menu structure to perform independent queries. Documentation for the ICSD consists of three manuals -- the User's Guide, the Operations Manual, and the Program Maintenance Manual. This Program Maintenance Manual provides the information necessary to maintain and update the ICSD system. Two major types of program maintenance documentation are presented in this manual. The first is the source code for the dBase III+ routines and related non-dBase programs used in operating the ICSD. The second is listings of the major component database field structures. A third important consideration for dBase programming, the structure of index files, is presented in the listing of source code for the index maintenance program. 1 fig

Condition-based inspection/replacement policies for non-monotone deteriorating systems with environmental covariates

Energy Technology Data Exchange (ETDEWEB)

Zhao Xuejing [Universite de Technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279, 12 rue Marie Curie, 10010 Troyes (France); School of mathematics and statistics, Lanzhou University, Lanzhou 730000 (China); Fouladirad, Mitra, E-mail: mitra.fouladirad@utt.f [Universite de Technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279, 12 rue Marie Curie, 10010 Troyes (France); Berenguer, Christophe [Universite de Technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279, 12 rue Marie Curie, 10010 Troyes (France); Bordes, Laurent [Universite de Pau et des Pays de l' Adour, LMA UMR CNRS 5142, 64013 PAU Cedex (France)

2010-08-15

The aim of this paper is to discuss the problem of modelling and optimising condition-based maintenance policies for a deteriorating system in presence of covariates. The deterioration is modelled by a non-monotone stochastic process. The covariates process is assumed to be a time-homogenous Markov chain with finite state space. A model similar to the proportional hazards model is used to show the influence of covariates on the deterioration. In the framework of the system under consideration, an appropriate inspection/replacement policy which minimises the expected average maintenance cost is derived. The average cost under different conditions of covariates and different maintenance policies is analysed through simulation experiments to compare the policies performances.

Condition-based inspection/replacement policies for non-monotone deteriorating systems with environmental covariates

International Nuclear Information System (INIS)

Zhao Xuejing; Fouladirad, Mitra; Berenguer, Christophe; Bordes, Laurent

2010-01-01

The aim of this paper is to discuss the problem of modelling and optimising condition-based maintenance policies for a deteriorating system in presence of covariates. The deterioration is modelled by a non-monotone stochastic process. The covariates process is assumed to be a time-homogenous Markov chain with finite state space. A model similar to the proportional hazards model is used to show the influence of covariates on the deterioration. In the framework of the system under consideration, an appropriate inspection/replacement policy which minimises the expected average maintenance cost is derived. The average cost under different conditions of covariates and different maintenance policies is analysed through simulation experiments to compare the policies performances.

Program integration of predictive maintenance with reliability centered maintenance

International Nuclear Information System (INIS)

Strong, D.K. Jr; Wray, D.M.

1990-01-01

This paper addresses improving the safety and reliability of power plants in a cost-effective manner by integrating the recently developed reliability centered maintenance techniques with the traditional predictive maintenance techniques of nuclear power plants. The topics of the paper include a description of reliability centered maintenance (RCM), enhancing RCM with predictive maintenance, predictive maintenance programs, condition monitoring techniques, performance test techniques, the mid-Atlantic Reliability Centered Maintenance Users Group, test guides and the benefits of shared guide development

Machinery prognostics and prognosis oriented maintenance management

CERN Document Server

Yan, Jihong

2014-01-01

This book gives a complete presentatin of the basic essentials of machinery prognostics and prognosis oriented maintenance management, and takes a look at the cutting-edge discipline of intelligent failure prognosis technologies for condition-based maintenance.  Latest research results and application methods are introduced for signal processing, reliability moelling, deterioration evaluation, residual life prediction and maintenance-optimization as well as applications of these methods.

Integrated maintenance program (IMP)

International Nuclear Information System (INIS)

Zemdegs, R.T.; Chout, Q.B.

1998-01-01

Approaches to the maintenance of nuclear power plants have undergone significant change in the past several decades. The traditional breakdown approach has been displaced by preventive (calendar-based) maintenance and more recently, by condition-based maintenance (CBM). This is largely driven by the fact that traditional maintenance programs, derived primarily from equipment vendor recommendations, are generally unsuccessful in controlling maintenance costs or equipment failures. Many advances in the maintenance field have taken place since the maintenance plans for Ontario Hydro's nuclear plants were initially established. Ontario Hydro nuclear plant operating costs can be substantially reduced and Incapability Factor improved with the application of modern maintenance processes and tools. Pickering is designated as the lead station for IMP. Of immediate concern is the fact that Pickering Nuclear Division has been experiencing a significant backlog of Operating Preventive Maintenance Callups. This backlog, over 2000, is unacceptable to both station management and the nuclear regulator, the Atomic Energy Control Board. In addition there are over 500 callups in various stages of revision (in hyperspace) without an adequate control nor reporting system to manage their completion. There is also considerable confusion about the classification of l icensing c allups, e.g. callups which are mandatory as a result of legal requirements. Furthermore the ineffectiveness of the Preventive Maintenance (PM) has been the subject of peer audits and Atomic Energy Control Board (AECB) findings over the past several years. The current preventive maintenance ratio PM2 /(PM+CM3) at Pickering ND is less than 20%, due to the current high load of equipment breakdown. This past summer, an Independent Integrated Performance Assessment (IIPA) review at Ontario Hydro confirmed these concerns. Over the past several years, Ontario Hydro nuclear staff have evaluated several programs to improve

Model-based fault diagnosis framework for effective predictive maintenance / B.B. Akindele

OpenAIRE

Akindele, Babatunde Babajide

2010-01-01

Predictive maintenance is a proactive maintenance strategy that is aimed at preventing the unexpected failure of equipment through condition monitoring of the health and performance of the equipment. Incessant equipment outage resulting in low availability of production facilities is a major issue in the Nigerian manufacturing environment. Improving equipment availability in Nigeria industry through institution of a full featured predictive maintenance has been suggested by many authors. T...

Health risk air-conditioning system; Insufficient maintenance increases the risk of illness. Gesundheitsrisiko Klimaanlagen; Unzureichende Wartung erhoeht das Erkrankungsrisiko

Energy Technology Data Exchange (ETDEWEB)

Anon.

1994-01-01

In Germany every fifth employee who works in air-conditioned rooms complains about headache, an increased proneness to colds and influenza infections as well as allergic reactions. These troubles are often caused by the insufficient maintenance of air-conditioning systems. At present only 15% of the estimated annual demand for maintenance of space hvac-systems is actually carried out. Problematic in case of air-conditioning systems are the so-called air washers used for air humidification which can become an ideal cultur medium for microorganisms. A second problematic area are the often very dirty filters. But health risks can be avoided with regular expert maintenance alone. As first step an analysis of the causes of faults is proposed. (BWI)

Optimal policies for cumulative damage models with maintenance last and first

International Nuclear Information System (INIS)

Zhao, Xufeng; Qian, Cunhua; Nakagawa, Toshio

2013-01-01

From the economical viewpoint of several combined PM policies in reliability theory, this paper takes up a standard cumulative damage model in which the notion of maintenance last is applied, i.e., the unit undergoes preventive maintenances before failure at a planned time T, at a damage level Z, or at a shock number N, whichever occurs last. Expected cost rates are detailedly formulated, and optimal problems of two alternative policies which combine time-based with condition-based preventive maintenances are discussed, i.e., optimal T L ⁎ for N, Z L ⁎ for T, and N L ⁎ for T are rigorously obtained. Comparison methods between such maintenance last and conventional maintenance first are explored. It is determined theoretically and numerically which policy should be adopted, according to the different methods in different cases when the time-based or the condition-based PM policy is optimized.

A Real-Time Quantitative Condition Alerting and Analysis Support System for Aircraft Maintenance, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Financial constraints, government recommendations, and the need for improved operational efficiency are requiring airlines to review their "on-condition" maintenance...

Model based decision support for planning of road maintenance

NARCIS (Netherlands)

van Harten, Aart; Worm, J.M.; Worm, J.M.

1996-01-01

In this article we describe a Decision Support Model, based on Operational Research methods, for the multi-period planning of maintenance of bituminous pavements. This model is a tool for the road manager to assist in generating an optimal maintenance plan for a road. Optimal means: minimising the

Maintenance management sourcing strategies and the condition of ...

African Journals Online (AJOL)

In the face of the deplorable state of buildings across the various tertiary institutions in Nigeria, the need to deploy appropriate maintenance management strategy cannot be overemphasized. However, sourcing decision for maintenance services remains a tough one for decision makers as different sourcing option suit ...

Psychological Conditions of Engagement among Community College Maintenance Employees: A Cross-Sectional Study

Science.gov (United States)

Franks, Tammy T.

2017-01-01

This dissertation examined the relationship between employee engagement and the factors that may influence the three psychological conditions of engagement: meaningfulness, safety, and availability for the sector of employees classified as maintenance, grounds, and custodial employees in a community college setting. The factors for each of the…

Optimal, Risk-based Operation and Maintenance Planning for Offshore Wind Turbines

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard

2008-01-01

For offshore wind turbines costs to operation and maintenance are substantial. This paper describes a risk-based life-cycle approach for optimal planning of operation and maintenance. The approach is based on pre-posterior Bayesian decision theory. Deterioration mechanisms such as fatigue...

Knowledge engineering thinking of maintenance

International Nuclear Information System (INIS)

2007-01-01

Maintenance optimization problem could not always settled mathematically and was obliged to use quasi-optimum solution with omitting non-formulated limiting condition or neglecting part of optimization object. In such a case knowledge engineering thinking was encouraged. Maintenance of complicated plant and artificial system should be considered from artificial object (equipment/facility hardware and system), technical information and knowledge base, and organizational and human aspect or society and institution. Comprehensive management system in organization and society was necessary not only for assuring integrity of equipment but also for attaining higher performance, reliability and economics of system. For better judgment it was important to share mechanism to make use of more information with organization or whole society. It was required to create database and data mining for knowledge base management system of maintenance. Maintenance was called 'last fortress' to assure quality such as reliability and safety of required function of equipment. Strategic approach to develop maintenance technology under cooperation was considered. Life extension R and D road map was launched in 2005. (T. Tanaka)

Reliability-centered maintenance for ground-based large optical telescopes and radio antenna arrays

Science.gov (United States)

Marchiori, G.; Formentin, F.; Rampini, F.

2014-07-01

In the last years, EIE GROUP has been more and more involved in large optical telescopes and radio antennas array projects. In this frame, the paper describes a fundamental aspect of the Logistic Support Analysis (LSA) process, that is the application of the Reliability-Centered Maintenance (RCM) methodology for the generation of maintenance plans for ground-based large optical telescopes and radio antennas arrays. This helps maintenance engineers to make sure that the telescopes continue to work properly, doing what their users require them to do in their present operating conditions. The main objective of the RCM process is to establish the complete maintenance regime, with the safe minimum required maintenance, carried out without any risk to personnel, telescope and subsystems. At the same time, a correct application of the RCM allows to increase the cost effectiveness, telescope uptime and items availability, and to provide greater understanding of the level of risk that the organization is managing. At the same time, engineers shall make a great effort since the initial phase of the project to obtain a telescope requiring easy maintenance activities and simple replacement of the major assemblies, taking special care on the accesses design and items location, implementation and design of special lifting equipment and handling devices for the heavy items. This maintenance engineering framework is based on seven points, which lead to the main steps of the RCM program. The initial steps of the RCM process consist of: system selection and data collection (MTBF, MTTR, etc.), definition of system boundaries and operating context, telescope description with the use of functional block diagrams, and the running of a FMECA to address the dominant causes of equipment failure and to lay down the Critical Items List. In the second part of the process the RCM logic is applied, which helps to determine the appropriate maintenance tasks for each identified failure mode. Once

Risk-Based Predictive Maintenance for Safety-Critical Systems by Using Probabilistic Inference

Directory of Open Access Journals (Sweden)

Tianhua Xu

2013-01-01

Full Text Available Risk-based maintenance (RBM aims to improve maintenance planning and decision making by reducing the probability and consequences of failure of equipment. A new predictive maintenance strategy that integrates dynamic evolution model and risk assessment is proposed which can be used to calculate the optimal maintenance time with minimal cost and safety constraints. The dynamic evolution model provides qualified risks by using probabilistic inference with bucket elimination and gives the prospective degradation trend of a complex system. Based on the degradation trend, an optimal maintenance time can be determined by minimizing the expected maintenance cost per time unit. The effectiveness of the proposed method is validated and demonstrated by a collision accident of high-speed trains with obstacles in the presence of safety and cost constrains.

Condition based maintenance of a 20 kV-PE/XLPE-insulated cable network using the IRC-Analysis; Zustandsorientierte Instandhaltung eines polymerisolierten 20-kV-Kabelnetzes mit der IRC-Analyse. Moderne Diagnostik reduziert Stoerungsrate

Energy Technology Data Exchange (ETDEWEB)

Hoff, G.; Kranz, H.G. [BUGH Wuppertal (Germany). Labs. fuer Hochspannungstechnik; Beigert, M.; Petzold, F. [Seba Dynatronic Mess- und Ortungstechnik GmbH, Baunach (Germany); Kneissl, C. [Bereich Konzeption und Messtechnik, Lech Elektrizitaetswerke AG, Augsburg (Germany)

2001-10-22

For a preventive maintenance of a polymer insulated cable network a destruction free estimation of the status of the buried PE/XLPE-cables is needed. This contribution presents a condition based maintenance concept which is based on the IRC-Analysis. With this concept a major German utility was able to reduce the amount of failures in a part of the 20kV-cable network. The general tendency of increasing faults was broken. (orig.) [German] Die praeventive Instandhaltung in polymerisolierten Kabelnetzen setzt eine zerstoerungsfreie Zustandbestimmung von gelegten PE/VPE-isolierten Kabeln voraus. Die-Verfasser beschreiben ein zustandsorientiertes Wartungskonzept auf Basis der IRC-Analyse, mit dem es gelungen ist, in einem Teil des 20-kV-Kabelnetzes eines Energieversorgers die in der Vergangenheit stetig steigende Stoerungsrate drastisch zu reduzieren. (orig.)

A multi-agent based intelligent configuration method for aircraft fleet maintenance personnel

OpenAIRE

Feng, Qiang; Li, Songjie; Sun, Bo

2014-01-01

A multi-agent based fleet maintenance personnel configuration method is proposed to solve the mission oriented aircraft fleet maintenance personnel configuration problem. The maintenance process of an aircraft fleet is analyzed first. In the process each aircraft contains multiple parts, and different parts are repaired by personnel with different majors and levels. The factors and their relationship involved in the process of maintenance are analyzed and discussed. Then the whole maintenance...

Consistency maintenance for constraint in role-based access control model

Institute of Scientific and Technical Information of China (English)

韩伟力; 陈刚; 尹建伟; 董金祥

2002-01-01

Constraint is an important aspect of role-based access control and is sometimes argued to be the principal motivation for role-based access control (RBAC). But so far few authors have discussed consistency maintenance for constraint in RBAC model. Based on researches of constraints among roles and types of inconsistency among constraints, this paper introduces corresponding formal rules, rule-based reasoning and corresponding methods to detect, avoid and resolve these inconsistencies. Finally, the paper introduces briefly the application of consistency maintenance in ZD-PDM, an enterprise-oriented product data management (PDM) system.

A multi-agent based intelligent configuration method for aircraft fleet maintenance personnel

Directory of Open Access Journals (Sweden)

Feng Qiang

2014-04-01

Full Text Available A multi-agent based fleet maintenance personnel configuration method is proposed to solve the mission oriented aircraft fleet maintenance personnel configuration problem. The maintenance process of an aircraft fleet is analyzed first. In the process each aircraft contains multiple parts, and different parts are repaired by personnel with different majors and levels. The factors and their relationship involved in the process of maintenance are analyzed and discussed. Then the whole maintenance process is described as a 3-layer multi-agent system (MAS model. A communication and reasoning strategy among the agents is put forward. A fleet maintenance personnel configuration algorithm is proposed based on contract net protocol (CNP. Finally, a fleet of 10 aircraft is studied for verification purposes. A mission type with 3 waves of continuous dispatch is imaged. Compared with the traditional methods that can just provide configuration results, the proposed method can provide optimal maintenance strategies as well.

Pacific Northwest Laboratory Maintenance Implementation plan

International Nuclear Information System (INIS)

Bright, J.D.

1992-06-01

This Maintenance Implementation plan has been developed for Pacific Northwest Laboratory's (PNL) Nuclear Facilities: 306W, 324, 325, 327 and 329NMF. It is based on a graded approach, self-assessment of the existing maintenance program(s) per the requirements specified by US Department of Energy (DOE) Order 4330.4A, Chapter II, Change number-sign 3. The results of this assessment were evaluated to determine needed improvements in PNL Craft Services' current maintenance program. The objective of this implementation plan is to provide baseline information for compliance to the DOE 4330.4A, and for needed improvements. The prime consideration in applying a graded approach to the Order has been to maintain safe and reliable operations, environmental compliance, safeguards and security, programmatic mission, facility preservation, and/or other facility-specific requirements. Using the results of the self-assessment, PNL has selected nine of the 18 elements of the Maintenance Program defined by DOE Order 4330.4A for improvement. The elements selected for improvement are Training and Qualification of Maintenance Personnel; Maintenance Procedures; Planning, Scheduling, and Coordination of Maintenance; Control of Maintenance Activities; Post-Maintenance Testing; Facility Condition Inspection; Management Involvement; Maintenance History; and Additional Maintenance Requirements. Based upon graded approach and current funding, those elements considered most important have been selected as goals for earliest compliance. Commitment dates for these elements have been established for compliance. The remaining elements of noncompliance will be targeted for implementation during later budget periods

Costs of performance based maintenance for local roads: Case study Albania

Science.gov (United States)

Jokanović, Igor; Grujić, Bojana; Zeljić, Dragana; Grujić, Žarko; Svilar, Mila

2017-12-01

The provision and maintenance of road infrastructure is a major global business, consequently it is essential that road maintenance services are provided in the most cost effective manner. Without regular maintenance, roads can rapidly fall into disrepair, preventing realization of the longer term impacts of road improvements on development, such as increased agricultural production and growth in school enrollment, which is of particular importance for a network of local (access) roads. Inadequate local roads maintenance in Albania is proposed to be solved by implementing performance based maintenance approach for which the costing exercise is presented within the paper.

Preventive maintenance plan of the air-conditioning duct using the ACM-sensor

International Nuclear Information System (INIS)

Fukuba, Kazushi; Ito, Takanobu; Kojima, Akiko; Tanji, Kazuhiro; Sato, Yuki

2013-01-01

Air-conditioning duct is difficult to predict the date to occur of corrosion such as affect the function. Therefore, the current conservation method is mostly corrective maintenance. Therefore, we used the test pieces of six types and ACM-sensor in order to solve the corrosion speed from corrosion environment and relationship of corrosion quantity of test pieces. In addition, was used the duct molded articles various in order to check the corrosion degree of when processed the duct. As a result, we were selected crust body constituting a duct and optimal combination of the flange by solve the corrosion speed of the test pieces various. Thus, it performs preventive disposal before to occur of corrosion such as affect the function by predicting the duct life from corrosion speed, and lead to stability and safe operating by appropriate maintenance of equipment. (author)

Methods and tools in development in the field of maintenance; Methodes et outils pour la maintenance en cours de developpement

Energy Technology Data Exchange (ETDEWEB)

Le Reverend, D.; Tortolano, M. [Electricite de France (EDF/RD), 78 - Chatou (France); Leniaud, F. [Electricite de France (EDF), Div. Production Nuleaire, 93 - Saint-Denis (France)

2004-07-01

This article is dedicated to the maintenance strategy followed by EDF for its nuclear power plants. This strategy is based on the American method RCM (reliability centered method) that has been extended to passive components such as structures and relies on 4 axis. The first axis can be defined as the optimization of maintenance with regard to safety, outage and costs. The aim is to set the border between preventive maintenance and remedial maintenance. The second axis is the condition based maintenance that is the maintenance action that is triggered by the real state of the equipment. This type of maintenance implies the search for reliable and accurate diagnostics. The third axis is the design of simulation and planning tools required for the management of the moving of tools, machinery and spare-parts on a maintenance work site. The fourth axis is the design of tools able to repair some important equipment, this way may be a valid alternative to the replacement of equipment in terms of cost and outage time. (A.C.)

Risk Based Maintenance in Electricity Network Organisations

NARCIS (Netherlands)

Mehairjan, R.P.Y.

2016-01-01

Presently, maintenance management of assets in infrastructure utilities such as electricity, gas and water are widely undergoing changes towards new working environments. These are mainly driven against the background of stringent regulatory regimes, an ageing asset base, increased customer demands

Pedagogical conditions of maintenance of integrity of process of socialization-individualization of children-orphans

OpenAIRE

Pronina A. N.

2011-01-01

Formation of the high-grade person of children of preschool age, without parental support should be carried out in complete process of socialization-individualization that assumes working out of the pedagogical conditions directed on maintenance of interrelation of processes of socialization and an individualization.

Advanced Maintenance Simulation by Means of Hand-Based Haptic Interfaces

Science.gov (United States)

Nappi, Michele; Paolino, Luca; Ricciardi, Stefano; Sebillo, Monica; Vitiello, Giuliana

Aerospace industry has been involved in virtual simulation for design and testing since the birth of virtual reality. Today this industry is showing a growing interest in the development of haptic-based maintenance training applications, which represent the most advanced way to simulate maintenance and repair tasks within a virtual environment by means of a visual-haptic approach. The goal is to allow the trainee to experiment the service procedures not only as a workflow reproduced at a visual level but also in terms of the kinaesthetic feedback involved with the manipulation of tools and components. This study, conducted in collaboration with aerospace industry specialists, is aimed to the development of an immersive virtual capable of immerging the trainees into a virtual environment where mechanics and technicians can perform maintenance simulation or training tasks by directly manipulating 3D virtual models of aircraft parts while perceiving force feedback through the haptic interface. The proposed system is based on ViRstperson, a virtual reality engine under development at the Italian Center for Aerospace Research (CIRA) to support engineering and technical activities such as design-time maintenance procedure validation, and maintenance training. This engine has been extended to support haptic-based interaction, enabling a more complete level of interaction, also in terms of impedance control, and thus fostering the development of haptic knowledge in the user. The user’s “sense of touch” within the immersive virtual environment is simulated through an Immersion CyberForce® hand-based force-feedback device. Preliminary testing of the proposed system seems encouraging.

A randomized controlled trial of interim methadone maintenance.

Science.gov (United States)

Schwartz, Robert P; Highfield, David A; Jaffe, Jerome H; Brady, Joseph V; Butler, Carol B; Rouse, Charles O; Callaman, Jason M; O'Grady, Kevin E; Battjes, Robert J

2006-01-01

Effective alternatives to long waiting lists for entry into methadone hydrochloride maintenance treatment are needed to reduce the complications of continuing heroin dependence and to increase methadone treatment entry. To compare the effectiveness of interim methadone maintenance with that of the usual waiting list condition in facilitating methadone treatment entry and reducing heroin and cocaine use and criminal behavior. Randomized, controlled, clinical trial using 2 conditions, with treatment assignment on a 3:2 basis to interim maintenance-waiting list control. A methadone treatment program in Baltimore. A total of 319 individuals meeting the criteria for current heroin dependence and methadone maintenance treatment. Participants were randomly assigned to either interim methadone maintenance, consisting of an individually determined methadone dose and emergency counseling only for up to 120 days, or referral to community-based methadone treatment programs. Entry into comprehensive methadone maintenance therapy at 4 months from baseline; self-reported days of heroin use, cocaine use, and criminal behavior; and number of urine drug test results positive for heroin and cocaine at the follow-up interview conducted at time of entry into comprehensive methadone treatment (or at 4 months from baseline for participants who did not enter regular treatment). Significantly more participants assigned to the interim methadone maintenance condition entered comprehensive methadone maintenance treatment by the 120th day from baseline (75.9%) than those assigned to the waiting list control condition (20.8%) (Pmethadone maintenance results in a substantial increase in the likelihood of entry into comprehensive treatment, and is an effective means of reducing heroin use and criminal behavior among opioid-dependent individuals awaiting entry into a comprehensive methadone treatment program.

Condition-based maintenance for a system subject to a non-homogeneous wear process with a wear rate transition

Energy Technology Data Exchange (ETDEWEB)

Fouladirad, Mitra, E-mail: mitra.fouladirad@utt.f [Universite de Technologie de Troyes, Institut Charles Delaunay, FRE CNRS 2848, 12 rue Marie Curie, 10010 Troyes (France); Grall, Antoine [Universite de Technologie de Troyes, Institut Charles Delaunay, FRE CNRS 2848, 12 rue Marie Curie, 10010 Troyes (France)

2011-06-15

The aim of this paper is to propose an adaptive maintenance model for a gradually deteriorating system. The system considered initially deteriorates with a nominal deterioration rate and at an unknown time the system's deterioration rate changes and the new deterioration rate is a time-dependent function. To deal with the transition of mode of deterioration in the framework of the maintenance decision rule an adequate online change detection algorithm is used. The maintenance decision rule is chosen in order to minimise the total maintenance cost including the cost of unavailability. The main result of this paper is to point out the interest of using a detection algorithm and hence the appreciation of a decision rule which takes into account transitions in the deterioration rate.

Condition-based maintenance for a system subject to a non-homogeneous wear process with a wear rate transition

International Nuclear Information System (INIS)

Fouladirad, Mitra; Grall, Antoine

2011-01-01

The aim of this paper is to propose an adaptive maintenance model for a gradually deteriorating system. The system considered initially deteriorates with a nominal deterioration rate and at an unknown time the system's deterioration rate changes and the new deterioration rate is a time-dependent function. To deal with the transition of mode of deterioration in the framework of the maintenance decision rule an adequate online change detection algorithm is used. The maintenance decision rule is chosen in order to minimise the total maintenance cost including the cost of unavailability. The main result of this paper is to point out the interest of using a detection algorithm and hence the appreciation of a decision rule which takes into account transitions in the deterioration rate.

Preventive maintenance technology for nuclear power stations

International Nuclear Information System (INIS)

Miyazawa, Tatsuo

1992-01-01

With the increase of the number of nuclear power plants in operation and the number of years of operation, the improvement of reliability and the continuation of safe operation have become more important, and the expectation for preventive maintenance technology has also heightened. The maintenance of Japanese nuclear power plants is based on the time schedule maintenance mainly by the regular inspection carried out every year, but the monitoring of the conditions of various machinery and equipment in operation has been performed widely. In this report, the present state of checkup and inspection technologies and the monitoring and diagnostic technologies for operational condition, which are the key technologies of preventive maintenance, are described. As the checkup and inspection technologies, ultrasonic flow detection technology, phased array technology, Amplituden und Laufzeit Orts Kurven method and X-ray CT, and as the monitoring and diagnostic technologies for operational condition, the diagnosis support system for BWR plants 'PLADIS', those for rotary machines, those for turbogenerators, those for solenoid valves, the mechanization of patrol works and the systematizing technology are reported. (K.I.)

Consistency maintenance for constraint in role-based access control model

Institute of Scientific and Technical Information of China (English)

韩伟力; 陈刚; 尹建伟; 董金祥

2002-01-01

Constraint is an important aspect of role-based access control and is sometimes argued to be the principal motivation for role-based access control (RBAC). But so far'few authors have discussed consistency maintenance for constraint in RBAC model. Based on researches of constraints among roles and types of inconsistency among constraints, this paper introduces correaponding formal rules, rulebased reasoning and corresponding methods to detect, avoid and resolve these inconsistencies. Finally,the paper introduces briefly the application of consistency maintenance in ZD-PDM, an enterprise-ori-ented product data management (PDM) system.

Reliability centred maintenance of nuclear power plant facilities

International Nuclear Information System (INIS)

Kovacs, Zoltan; Novakova, Helena; Hlavac, Pavol; Janicek, Frantisek

2011-01-01

A method for the optimization of preventive maintenance nuclear power plant equipment, i.e. reliability centred maintenance, is described. The method enables procedures and procedure schedules to be defined such as allow the maintenance cost to be minimized without compromising operational safety or reliability. Also, combinations of facilities which remain available and ensure reliable operation of the reactor unit during the maintenance of other pieces of equipment are identified. The condition-based maintenance concept is used in this process, thereby preventing unnecessary operator interventions into the equipment, which are often associated with human errors. Where probabilistic safety assessment is available, the most important structures, systems and components with the highest maintenance priority can be identified. (orig.)

Identification of National Road Maintenance Needs Based on Strategic Plan of Directorate General of Bina Marga (2015-2019

Directory of Open Access Journals (Sweden)

Rizky Ardhiarini

2016-05-01

Full Text Available The enhancement of connectivity between the main corridors of the economy in South Sumatera, as a purpose of the Strategic Plan of Directorate General Bina Marga and also an objective of MP3EI, Master Plan for Acceleration and expansion of Indonesia's Economic Development which is an ambitious plan by the Indonesian government to accelerate the realization of becoming a developed country would be able to achieve on the requirement of good condition on performance and pavement. In order to support the optimal condition of the road, the identification of road management was conducted to determine the necessity of road maintenance based on technical conditions and importance level of development of the road traversed. The management program proposed is expected to be used as a baseline in determining the maintenance of the road network in South Sumatera from 2015 until 2019. This research used Multi-criteria Analysis (MCA method, which consists of: (1 road network performance, covering width of roadways, traffic flow, V/C ratio, travel speed and travel time of the vehicle, and (2 pavement condition, with IRI, SDI, and the proportion of good pavement condition as a parameter. Multi-criteria analysis used combined road condition assessment score and importance level of development of the area traversed by. This analysis was conducted from 2015 until 2019. The research concluded that maintenance necessity in 2015 were dominated by routine maintenance (95.86% of the total length, then in 2016 until 2019 the needs were dominated by routine maintenance (near 100% of the total length. As the maintenance applied, a vast amount of total road length fulfilled as an achievement target. The results are follows: (a 100% with width of roadways ≥ 7 meter, (b 97.83% with V/C ratio  60km/hour, (d 17.32% with travel time (TT 95%, (f 90.37% with IRI < 4 m/Km, and (g 91.59 with SDI < 50. Yet with the achievement of 100% of total road length with a

Aging based maintenance and reinvestment scheduling of electric distribution

Energy Technology Data Exchange (ETDEWEB)

Korpijarvi, J.

2012-07-01

The maintenance of electric distribution network is a topical question for distribution system operators because of increasing significance of failure costs. In this dissertation the maintenance practices of the distribution system operators are analyzed and a theory for scheduling maintenance activities and reinvestment of distribution components is created. The scheduling is based on the deterioration of components and the increasing failure rates due to aging. The dynamic programming algorithm is used as a solving method to maintenance problem which is caused by the increasing failure rates of the network. The other impacts of network maintenance like environmental and regulation reasons are not included to the scope of this thesis. Further the tree trimming of the corridors and the major disturbance of the network are not included to the problem optimized in this thesis. For optimizing, four dynamic programming models are presented and the models are tested. Programming is made in VBA-language to the computer. For testing two different kinds of test networks are used. Because electric distribution system operators want to operate with bigger component groups, optimal timing for component groups is also analyzed. A maintenance software package is created to apply the presented theories in practice. An overview of the program is presented (orig.)

Structuring AHP-based maintenance policy selection

NARCIS (Netherlands)

Goossens, Adriaan; Basten, Robertus Johannes Ida; Hummel, J. Marjan; van der Wegen, Leonardus L.M.

2015-01-01

We aim to structure the maintenance policy selection process for ships, using the Analytic Hierarchy Process (AHP). Maintenance is an important contributor to reach the intended life-time of capital technical assets, and it is gaining increasing interest and relevance. A maintenance policy is a

PERFORMANCE-BASED CONTRACTING IN CONSTRUCTION PHASE AND MAINTENANCE PHASE OF PAVEMENT

Science.gov (United States)

Yoshida, Takeshi

Performance-based contracting for pavement in Japan started as performance warranties in construction phase, in 1999. Recently, road agencies have recognized the applicability of this type of contracting in outsourcing of maintenance activities. The objectives of this study are to clarify the issues of performance specifying in construction phase and maintenance phase of pavement, and to propose measures to be taken. This paper, with the recognition that the life of each pavement depends on performance standards for various attributes, reviews domestic and foreign examples of performance-based contracting. A performance standard based on the average of current practices can enhance product quality and service life with a warranty contract. Repair thresholds and response time for each deficiency should be considered as performance standards in maintenance phase.

Design of Mobile Operation and Maintenance System Based on Power GIS and GPS

Directory of Open Access Journals (Sweden)

Jing TAO

2017-01-01

Full Text Available In order to solve the low efficiency of operation and maintenance and the problems of management coordination caused by the coexistence of off-line operation and maintenance and multi system coexistence in current power telecommunication operation and maintenance, this paper proposes a mobile operation and maintenance system based on power GIS and GPS location technology. The system is based on the C/S architecture, and the mobile operation and maintenance terminal is connected with the operation and maintenance management terminal through wireless and wired network. In addition to meeting basic business requirements, the system integrates power GIS functions to visually demonstrate communication resources, personnel, and failures. The staff can use the wireless mobile terminal which integrated GPS module for to operate and maintain, and can locate accurately in real time.

A COMPUTER BASED MAINTENANCE MANAGEMENT SYSTEM ...

African Journals Online (AJOL)

... programs to schedule for maintenance or replacement of machines has been designed such that it enables the maintenance department control all jobs associated with plant maintenance and breakdown. It predicts the time to failure of designated plants and caters for the replacement analysis of some capital equipment.

A maintenance policy for two-unit parallel systems based on imperfect monitoring information

Energy Technology Data Exchange (ETDEWEB)

Barros, Anne [Department Genie des Systems Industiels (GSI), Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes, Cedex (France)]. E-mail: anne.barros@utt.fr; Berenguer, Christophe [Department Genie des Systems Industiels (GSI), Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes, Cedex (France); Grall, Antoine [Department Genie des Systems Industiels (GSI), Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes, Cedex (France)

2006-02-01

In this paper a maintenance policy is optimised for a two-unit system with a parallel structure and stochastic dependences. Monitoring problems are taken into account in the optimisation scheme: the failure time of each unit can be not detected with a given probability. Conditions on the system parameters (unit failure rates) and on the non-detection probabilities must be verified to make the optimisation scheme valid. These conditions are clearly identified. Numerical experiments allow to show the relevance of taking into account monitoring problems in the maintenance model.

A maintenance policy for two-unit parallel systems based on imperfect monitoring information

International Nuclear Information System (INIS)

Barros, Anne; Berenguer, Christophe; Grall, Antoine

2006-01-01

In this paper a maintenance policy is optimised for a two-unit system with a parallel structure and stochastic dependences. Monitoring problems are taken into account in the optimisation scheme: the failure time of each unit can be not detected with a given probability. Conditions on the system parameters (unit failure rates) and on the non-detection probabilities must be verified to make the optimisation scheme valid. These conditions are clearly identified. Numerical experiments allow to show the relevance of taking into account monitoring problems in the maintenance model

Paper number: ID 576... Monitoring and maintenance of pumps in LWR

International Nuclear Information System (INIS)

Heller, M.; Einzmann, K.

2001-01-01

Due to the liberalization of the European Market for electrical power nuclear power plants are progressively subjected to high pressure in respect of reducing the overall costs including for maintenance actions. This concerns also the maintenance of active components as pumps or valves. Siemens Nuclear Power (SNP) has developed a concept for the transition to an integrated condition based maintenance especially for pumps which shall be presented below. It is proposed to make up future decisions on maintenance of pumps only depending on condition data of the component. The concept must be supported by modern monitoring systems, which shall be installed at pumps which are relevant for the safety and availability of the plants. The main technical features of the SNP monitoring system DIROM are presented in detail as an example. First results of acquiring condition related data of a nuclear feed water pump are reported too. The new maintenance concept promises attractive cost benefits in comparison to a former preventive maintenance concept. (author)

Analytical method for optimization of maintenance policy based on available system failure data

International Nuclear Information System (INIS)

Coria, V.H.; Maximov, S.; Rivas-Dávalos, F.; Melchor, C.L.; Guardado, J.L.

2015-01-01

An analytical optimization method for preventive maintenance (PM) policy with minimal repair at failure, periodic maintenance, and replacement is proposed for systems with historical failure time data influenced by a current PM policy. The method includes a new imperfect PM model based on Weibull distribution and incorporates the current maintenance interval T 0 and the optimal maintenance interval T to be found. The Weibull parameters are analytically estimated using maximum likelihood estimation. Based on this model, the optimal number of PM and the optimal maintenance interval for minimizing the expected cost over an infinite time horizon are also analytically determined. A number of examples are presented involving different failure time data and current maintenance intervals to analyze how the proposed analytical optimization method for periodic PM policy performances in response to changes in the distribution of the failure data and the current maintenance interval. - Highlights: • An analytical optimization method for preventive maintenance (PM) policy is proposed. • A new imperfect PM model is developed. • The Weibull parameters are analytically estimated using maximum likelihood. • The optimal maintenance interval and number of PM are also analytically determined. • The model is validated by several numerical examples

Predictive maintenance technology development at G.A. Siwabessy multipurpose reactor

Energy Technology Data Exchange (ETDEWEB)

Jupiter Sitorus Pane; Imron, M.; Sapto Hartoko; Sentot Alibasya Harahap [Multipurpose Research Reactor G.A. Siwabessy, National Nuclear Energy Agency (Indonesia)

1999-10-01

Safe operation of reactor is certainly influenced by condition of system and component equipped to the reactor's system. In order to maintain the condition of that systems and components, RSG-GAS has arranged maintenance program with time-basis. All 6 (six) groups of reactor systems are maintained within interval of weekly, monthly, three monthly, six-monthly, yearly, five-yearly appropriately. The experience showed that event though the maintenance was performed persistently, the condition of system and component are still not able to determine exactly. The possibility of accidental failure is open since the failure factor are varied and complicated. In order to limit an uncertainty of the component condition a based maintenance shall be introduced. An infrared investigation and manual vibration analysis had been used to diagnose the condition of some RSG-GAS' components. In addition, other alternative technology for predictive maintenance was developed. It is started by computerizing the database maintenance and doing historical review for its aging management, and developing data acquisition and processing equipment using Lab View computer program for collecting and processing signal data from dynamics system. This paper describes briefly the status of those development results. (author)

Predictive maintenance technology development at G.A. Siwabessy multipurpose reactor

International Nuclear Information System (INIS)

Jupiter Sitorus Pane; Imron, M.; Sapto Hartoko; Sentot Alibasya Harahap

1999-01-01

Safe operation of reactor is certainly influenced by condition of system and component equipped to the reactor's system. In order to maintain the condition of that systems and components, RSG-GAS has arranged maintenance program with time-basis. All 6 (six) groups of reactor systems are maintained within interval of weekly, monthly, three monthly, six-monthly, yearly, five-yearly appropriately. The experience showed that event though the maintenance was performed persistently, the condition of system and component are still not able to determine exactly. The possibility of accidental failure is open since the failure factor are varied and complicated. In order to limit an uncertainty of the component condition a based maintenance shall be introduced. An infrared investigation and manual vibration analysis had been used to diagnose the condition of some RSG-GAS' components. In addition, other alternative technology for predictive maintenance was developed. It is started by computerizing the database maintenance and doing historical review for its aging management, and developing data acquisition and processing equipment using Lab View computer program for collecting and processing signal data from dynamics system. This paper describes briefly the status of those development results. (author)

Residual life management. Maintenance improvement

International Nuclear Information System (INIS)

Sainero Garcia, J.; Hevia Ruperez, F.

1995-01-01

The terms Residual Life Management, Life Cycle Management and Long-Term Management are synonymous with a concept which aims to establish efficient maintenance for the profitable and safe operation of a power plant for as long as possible. A Residual Life Management programme comprises a number of stages, of which Maintenance Evaluation focuses on how power plant maintenance practices allow the mitigation and control of component ageing. with this objective in mind, a methodology has been developed for the analysis of potential degradative phenomena acting on critical components in terms of normal power plant maintenance practices. This methodology applied to maintenance evaluation enables the setting out of a maintenance programme based on the Life Management concept, and the programme's subsequent up-dating to allow for new techniques and methods. Initial applications have shown that although, in general terms, power plant maintenance is efficient, the way in which Residual Life Management is approached requires changes in maintenance practices. These changes range from modifications to existing inspection and surveillance methods or the establishment of new ones, to the monitoring of trends or the performance of additional studies, the purpose of which is to provide an accurate evaluation of the condition of the installations and the possibility of life extension. (Author)

Risk-based equipment removal guide for on-line maintenance at PSE ampersand G

International Nuclear Information System (INIS)

Knoll, A.; Smith, C.; Pollock, J.

1995-01-01

On-line maintenance plays an important role in achieving safe and reliable power generation in a nuclear power plant. However, maintenance, if not properly planned and performed, may also be an important contributor to plant risk. Therefore, plant-specific procedures are needed for equipment removal from service to enhance the benefits of on-line maintenance and minimize the risks involved. The problem is to identify and implement the most effective on-line maintenance policy in the form of a proceduralized guide to assure plant safety under various operation and maintenance constraints. This paper presents a methodology to develop plant-specific on-line maintenance strategies and acceptance criteria using a multivariate safety approach based on risk assessment. Based on plant-specific data as modeled in the individual plant evaluation (IPE) and the updated probabilistic safety assessment (PSA), the risk-based methodology is currently being applied to the development of proceduralized equipment removal guides at Hope Creek and Salem units 1 and 2 of Public Service Electric and Gas Company (PSE ampersand G)

Assessment and improvement of urban streets maintenance: Case study Kragujevac

Directory of Open Access Journals (Sweden)

Jokanović Igor

2017-01-01

Full Text Available City of Kragujevac struggles with providing road maintenance services due to limited funds and low capacity within the existing Public Utility Companies. As a solution to problems with traditional methods of contracting, many road authorities have moved to contracting road maintenance works to the private sector based on performance measures. The paper presents the outcomes of the study conducted for the purpose of improving current practice and condition of urban network within the City of Kragujevac through the application of performance-based maintenance contracting.

Research of nuclear power plant in-service maintenance based on virtual reality

International Nuclear Information System (INIS)

Wang Yong; Kuang Weijun

2015-01-01

This paper presents a method of constructing nuclear power plant in-service maintenance virtual simulation scene and virtual maintenance process. Taking air baffles dismantling process of CAP1400(China Advanced Passive 1400) nuclear power plant as an instance, this paper discusses ergonomics, space analysis, time assessment based on virtual reality in the process of in-service maintenance. It demonstrates the advantage of using VR technology to design and verify in-service maintenance process of nuclear power plant compared to the conventional way. (author)

Experience based reliability centered maintenance

International Nuclear Information System (INIS)

Haenninen, S.; Laakso, K.

1993-03-01

The systematic analysis and documentation of operating experiences should be included in a living NPP life management program. Failure mode and effects and maintenance effects analyses are suitable methods for analysis of the failure and corrective maintenance experiences of equipment. Combined use of the information on occurred functional failures and the decision tree logic of the reliability centered maintenance identifies applicable and effective preventive maintenance tasks of equipment in an old plant. In this study the electrical motor drives of closing and isolation valves (MOV) of TVO and Loviisa nuclear power plants were selected to serve as pilot study objects. The study was limited to valve drives having actuators manufactured by AUMA in Germany. The fault and maintenance history of MOVs from 1981 up to and including October 1991 in different safety and process systems at TVO 1 and 2 nuclear power units was at first analyzed in a systematic way. The scope of the components studied was 81 MOVs in safety-related systems and 127 other MOVs per each TVO unit. In the case of the Loviisa plant, the observation period was limited to three years, i.e. from February 1989 up to February 1992. The scope of the Loviisa 1 and 2 components studied was 44 respectively 95 MOVs. (25 refs., 22 figs., 8 tabs.)

Developing Mobile- and BIM-Based Integrated Visual Facility Maintenance Management System

Directory of Open Access Journals (Sweden)

Yu-Cheng Lin

2013-01-01

Full Text Available Facility maintenance management (FMM has become an important topic for research on the operation phase of the construction life cycle. Managing FMM effectively is extremely difficult owing to various factors and environments. One of the difficulties is the performance of 2D graphics when depicting maintenance service. Building information modeling (BIM uses precise geometry and relevant data to support the maintenance service of facilities depicted in 3D object-oriented CAD. This paper proposes a new and practical methodology with application to FMM using BIM technology. Using BIM technology, this study proposes a BIM-based facility maintenance management (BIMFMM system for maintenance staff in the operation and maintenance phase. The BIMFMM system is then applied in selected case study of a commercial building project in Taiwan to verify the proposed methodology and demonstrate its effectiveness in FMM practice. Using the BIMFMM system, maintenance staff can access and review 3D BIM models for updating related maintenance records in a digital format. Moreover, this study presents a generic system architecture and its implementation. The combined results demonstrate that a BIMFMM-like system can be an effective visual FMM tool.

45 CFR 310.20 - What are the conditions for funding the installation, operation, maintenance and enhancement of...

Science.gov (United States)

2010-10-01

... Tribal IV-D Systems and Office Automation § 310.20 What are the conditions for funding the installation... 45 Public Welfare 2 2010-10-01 2010-10-01 false What are the conditions for funding the installation, operation, maintenance and enhancement of Computerized Tribal IV-D Systems and Office Automation...

Game-Theoretic Models for Usage-based Maintenance Contract

Science.gov (United States)

Husniah, H.; Wangsaputra, R.; Cakravastia, A.; Iskandar, B. P.

2018-03-01

A usage-based maintenance contracts with coordination and non coordination between two parties is studied in this paper. The contract is applied to a dump truck operated in a mining industry. The situation under study is that an agent offers service contract to the owner of the truck after warranty ends. This contract has only a time limit but no usage limit. If the total usage per period exceeds the maximum usage allowed in the contract, then the owner will be charged an additional cost. In general, the agent (Original Equipment Manufacturer/OEM) provides a full coverage of maintenance, which includes PM and CM under the lease contract. The decision problem for the owner is to select the best option offered that fits to its requirement, and the decision problem for the agent is to find the optimal maintenance efforts for a given price of the service option offered. We first find the optimal decisions using coordination scheme and then with non coordination scheme for both parties.

A Costing Analysis for Decision Making Grid Model in Failure-Based Maintenance

Directory of Open Access Journals (Sweden)

Burhanuddin M. A.

2011-01-01

Full Text Available Background. In current economic downturn, industries have to set good control on production cost, to maintain their profit margin. Maintenance department as an imperative unit in industries should attain all maintenance data, process information instantaneously, and subsequently transform it into a useful decision. Then act on the alternative to reduce production cost. Decision Making Grid model is used to identify strategies for maintenance decision. However, the model has limitation as it consider two factors only, that is, downtime and frequency of failures. We consider third factor, cost, in this study for failure-based maintenance. The objective of this paper is to introduce the formulae to estimate maintenance cost. Methods. Fish bone analysis conducted with Ishikawa model and Decision Making Grid methods are used in this study to reveal some underlying risk factors that delay failure-based maintenance. The goal of the study is to estimate the risk factor that is, repair cost to fit in the Decision Making Grid model. Decision Making grid model consider two variables, frequency of failure and downtime in the analysis. This paper introduces third variable, repair cost for Decision Making Grid model. This approaches give better result to categorize the machines, reduce cost, and boost the earning for the manufacturing plant. Results. We collected data from one of the food processing factories in Malaysia. From our empirical result, Machine C, Machine D, Machine F, and Machine I must be in the Decision Making Grid model even though their frequency of failures and downtime are less than Machine B and Machine N, based on the costing analysis. The case study and experimental results show that the cost analysis in Decision Making Grid model gives more promising strategies in failure-based maintenance. Conclusions. The improvement of Decision Making Grid model for decision analysis with costing analysis is our contribution in this paper for

Performance-based maintenance procurement by Dutch housing associations

NARCIS (Netherlands)

Straub, A.

2004-01-01

OTB Research institute has established a long-term research program to performance-based maintenance procurement in the technical management of housing stock. Stakeholders: housing associations, contractors and the Dutch Building Research Foundation are directly involved in this research program.

JRR-3 maintenance program utilizing accumulated maintenance data

International Nuclear Information System (INIS)

Izumo, Hironobu; Kato, Tomoaki; Kinase, Masami; Torii, Yoshiya; Murayama, Yoji

2007-07-01

JRR-3(Japan Research Reactor No.3) has been operated for more than 15 years after the modification, without significant troubles by carrying out maintenance such as the preventive maintenance (mainly time-based maintenance) for the safety-grade equipments and the breakdown maintenance for the non-safety-grade equipments. Unscheduled shutdowns causes by aged non-safety-grade equipments have been increasing, and the resources such as budgets have been decreasing year by year. In this situation, JRR-3 maintenance program was reviewed about safety, reliability and economic efficiency. This report offers the policy of the maintenance review and the future direction of maintenance programs. (author)

Development of maintenance tools based on tribology for nuclear power plant

International Nuclear Information System (INIS)

Iwai, Yoshiro; Honda, Tomomi; Yoshinaga, Shigeki

2007-01-01

Many tribological problems occur in the maintenance of nuclear power plants. In this paper, we introduced our developed maintenance tools based on tribology such as a particle counter and wear sensors. Their principals were shown briefly and their usefulness was clarified by the experiments on monitoring of wear. (author)

Wireless sensors for predictive maintenance of rotating equipment in research reactors

International Nuclear Information System (INIS)

Hashemian, H.M.

2011-01-01

In 2008-2009, the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL) tested the potential of predictive or condition-based maintenance techniques to reduce maintenance costs, minimize the risk of catastrophic failures, and maximize system availability by attaching wireless-based sensors to selected rotating equipment at HFIR. Rotating equipment is an ideal 'test case' for the viability of integrated, online predictive maintenance strategies because motors, bearings, and shafts are ubiquitous in nuclear power plants and because the maintenance methods typically performed on rotating equipment today (such as portable or handheld vibration data collection equipment) are highly labor-intensive. The HFIR project achieved all five of its objectives: (1) to identify rotating machinery of the types used in research reactors and determine their operational characteristics, degradation mechanisms, and failure modes, (2) to establish a predictive maintenance program for rotating equipment in research reactors, (3) to identify wireless sensors that are suitable for predictive maintenance of rotating machinery and test them in a laboratory setting, (4) to establish the requirements and procedures to be followed when implementing wireless sensors for predictive maintenance in research reactors, and (5) to develop a conceptual design for a predictive maintenance system for research reactors based on wireless sensors. The project demonstrated that wireless sensors offer an effective method for monitoring key process conditions continuously and remotely, thereby enhancing the safety, reliability, and efficiency of the aging research reactor fleet.

Addressing imperfect maintenance modelling uncertainty in unavailability and cost based optimization

International Nuclear Information System (INIS)

Sanchez, Ana; Carlos, Sofia; Martorell, Sebastian; Villanueva, Jose F.

2009-01-01

Optimization of testing and maintenance activities performed in the different systems of a complex industrial plant is of great interest as the plant availability and economy strongly depend on the maintenance activities planned. Traditionally, two types of models, i.e. deterministic and probabilistic, have been considered to simulate the impact of testing and maintenance activities on equipment unavailability and the cost involved. Both models present uncertainties that are often categorized as either aleatory or epistemic uncertainties. The second group applies when there is limited knowledge on the proper model to represent a problem, and/or the values associated to the model parameters, so the results of the calculation performed with them incorporate uncertainty. This paper addresses the problem of testing and maintenance optimization based on unavailability and cost criteria and considering epistemic uncertainty in the imperfect maintenance modelling. It is framed as a multiple criteria decision making problem where unavailability and cost act as uncertain and conflicting decision criteria. A tolerance interval based approach is used to address uncertainty with regard to effectiveness parameter and imperfect maintenance model embedded within a multiple-objective genetic algorithm. A case of application for a stand-by safety related system of a nuclear power plant is presented. The results obtained in this application show the importance of considering uncertainties in the modelling of imperfect maintenance, as the optimal solutions found are associated with a large uncertainty that influences the final decision making depending on, for example, if the decision maker is risk averse or risk neutral

Addressing imperfect maintenance modelling uncertainty in unavailability and cost based optimization

Energy Technology Data Exchange (ETDEWEB)

Sanchez, Ana [Department of Statistics and Operational Research, Polytechnic University of Valencia, Camino de Vera, s/n, 46071 Valencia (Spain); Carlos, Sofia [Department of Chemical and Nuclear Engineering, Polytechnic University of Valencia, Camino de Vera, s/n, 46071 Valencia (Spain); Martorell, Sebastian [Department of Chemical and Nuclear Engineering, Polytechnic University of Valencia, Camino de Vera, s/n, 46071 Valencia (Spain)], E-mail: smartore@iqn.upv.es; Villanueva, Jose F. [Department of Chemical and Nuclear Engineering, Polytechnic University of Valencia, Camino de Vera, s/n, 46071 Valencia (Spain)

2009-01-15

Optimization of testing and maintenance activities performed in the different systems of a complex industrial plant is of great interest as the plant availability and economy strongly depend on the maintenance activities planned. Traditionally, two types of models, i.e. deterministic and probabilistic, have been considered to simulate the impact of testing and maintenance activities on equipment unavailability and the cost involved. Both models present uncertainties that are often categorized as either aleatory or epistemic uncertainties. The second group applies when there is limited knowledge on the proper model to represent a problem, and/or the values associated to the model parameters, so the results of the calculation performed with them incorporate uncertainty. This paper addresses the problem of testing and maintenance optimization based on unavailability and cost criteria and considering epistemic uncertainty in the imperfect maintenance modelling. It is framed as a multiple criteria decision making problem where unavailability and cost act as uncertain and conflicting decision criteria. A tolerance interval based approach is used to address uncertainty with regard to effectiveness parameter and imperfect maintenance model embedded within a multiple-objective genetic algorithm. A case of application for a stand-by safety related system of a nuclear power plant is presented. The results obtained in this application show the importance of considering uncertainties in the modelling of imperfect maintenance, as the optimal solutions found are associated with a large uncertainty that influences the final decision making depending on, for example, if the decision maker is risk averse or risk neutral.

Maintenance strategy for tilting table of rolling mill based on reliability considerations

International Nuclear Information System (INIS)

Deshpande, V.S.; Modak, J.P.

2003-01-01

tilting tables are 14 scheduled on-condition tasks, 10 scheduled on-restoration tasks, seven scheduled discard task. Whereas for 14 failure modes no scheduled maintenance has been proposed. Existing maintenance schedule for tilting tables indicates the maintenance action as and when required. Hence RCM based schedule specifies that additional preventive maintenance tasks need to be executed as compared to none initially. Cost incurred for this can be offset from the savings accrued from reduction in loss of production due to repetitive breakdowns. The methodology of RCM adopted in western industries cannot be applied as it is to Indian industries because of labour oriented nature, partially computerised information systems, non-availability of the information about cost of loss of production due to breakdown and age-reliability pattern of equipment, insufficient maintenance database. These problems can be overcome by development of sound MMIS, formulation of RCM review group and imparting suitable training to acquire the relevant skills in RCM. Thus RCM methodology can be applied to Indian industry for reduction of breakdowns as well as optimisation of preventive maintenance cost. This can further boost up the prospects of Indian industry to offer the products at globally competitive prices

An Abstraction Hierarchy based mobile PC display design in NPP maintenance considering the level of expertise

International Nuclear Information System (INIS)

Yim, Ho Bin; Kim, In; Seong, Poong Hyun

2011-01-01

Research highlights: → Six levels of Abstraction Hierarchy based information for maintenance were proposed. → Errors and workload with AH based information display were reduced for LL subjects. → Design concerns discovered can be applied to practical use of mobile maintenance aids. - Abstract: Recently, the importance of effective maintenance in nuclear power plants (NPPs) has been emphasized and research into effective maintenance by adopting mobile maintenance aids (MMAs) have been attempted. For improved and effective use of an MMA display design method based on the hierarchy is proposed and its design considerations are discussed in this study. Six levels of hierarchy are proposed in this paper to classify the maintenance information. By classifying and organizing maintenance information using the hierarchy, maintenance information can be used effectively by users with either high or low levels of expertise. When information classification has been finished, the information for MMA design is selected and designed. With the considerations of MMA design analysis and guidelines, a hierarchy-based MMA is designed for the maintenance tasks. An experiment is conducted using the hierarchy-based MMA in order to estimate the effectiveness of the proposed method for the maintenance tasks and to identify design considerations to enhance the proposed MMAs. The result indicated that a hierarchy-based manual was more effective than a conventional manual in terms of task completion time and number of errors. The workload for the hierarchy-based manual was estimated less than the conventional manual for subjects with low level of expertise. As the level of expertise increases, subjects tended to follow more abstract information while the number of navigations decreased. It is believed that when mobile devices become pervasive in NPP maintenance fields, the hierarchy model applied MMAs can be used as an effective maintenance supporting tool.

Methadone maintenance therapy as evidence based drug abuse ...

African Journals Online (AJOL)

Methadone maintenance therapy as evidence based drug abuse planning in ... drugs are being used as artificial problem-solvers such as frustrations, stress or ... Drug use is a problem to users when it begins to cause some damage to their ...

Expert system for maintenance of nuclear power plants

International Nuclear Information System (INIS)

Ito, Tetsuo; Kasahara, Takayasu; Watanabe, Takao; Matsuki, Tsutomu.

1989-01-01

The basic function of the expert system which supports the maintenance works such as the diagnosis of nuclear power plants and the planning of maintenance works was developed. For the maintenance of large scale plants like nuclear power plants, much manpower is required. Consequently, it has been desired to develop the system for improving the maintainability by utilizing the expertise and empirical knowledge of skilled engineers. This system comprises the subsystems for aiding plant diagnosis and maintenance work planning. The former diagnoses the contents of out of order based on the knowledge base, and thereafter, guides the method of taking measures using simulator. The latter establishes the plan by using the method of limiting branching together so that the maintenance works do not interfere mutually or do not affect the operation. Hereafter, it is intended to improve the man-machine condition and expand knowledge aiming at the practical use. The outline of the system, the constitution of subsystems, the example of plant diagnosis, the support of plant maintenance work planning and so on are reported. (K.I.)

Reliability-based maintenance evaluations and standard preventive maintenance programs

International Nuclear Information System (INIS)

Varno, M.; McKinley, M.

1993-01-01

Due to recent issuance of 10CFR50.65, the U.S. Nuclear Regulatory Commission maintenance rule (Rule), and the open-quotes Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plantsclose quotes prepared by the Nuclear Management and Resources Council, many utilities are undertaking review or evaluation of current preventive maintenance (PM) programs. Although PM optimization and documentation are not specifically required by the Rule, an appropriate and effective PM program (PMP) will be the cornerstone of the successful and cost-effective implementation of the Rule. Currently, a project is being conducted at the Vermont Yankee Nuclear Power Station (VYNPS) in conjunction with Quadrex Energy Services to evaluate, optimize, and document the PMP. The project began in March 1993 and is scheduled for completion in mid-1995. The initial scope for the project is the evaluation of those structures, systems, and components that are within the scope of the Rule. Because of the number of systems to be evaluated (∼50), the desired completion schedule, and cost considerations, a streamlined approach to PM optimization and documentation is being utilized

Predictive maintenance policy for a gradually deteriorating system subject to stress

Energy Technology Data Exchange (ETDEWEB)

Deloux, E. [IRCCyN/Ecole des Mines de Nantes, Nantes (France); Castanier, B. [IRCCyN/Ecole des Mines de Nantes, Nantes (France)], E-mail: bruno.castanier@emn.fr; Berenguer, C. [Universite de Technologie de Troyes/CNRS, Troyes (France)

2009-02-15

This paper deals with a predictive maintenance policy for a continuously deteriorating system subject to stress. We consider a system with two failure mechanisms which are, respectively, due to an excessive deterioration level and a shock. To optimize the maintenance policy of the system, an approach combining statistical process control (SPC) and condition-based maintenance (CBM) is proposed. CBM policy is used to inspect and replace the system according to the observed deterioration level. SPC is used to monitor the stress covariate. In order to assess the performance of the proposed maintenance policy and to minimize the long-run expected maintenance cost per unit of time, a mathematical model for the maintained system cost is derived. Analysis based on numerical results are conducted to highlight the properties of the proposed maintenance policy in respect to the different maintenance parameters.

Predictive maintenance policy for a gradually deteriorating system subject to stress

International Nuclear Information System (INIS)

Deloux, E.; Castanier, B.; Berenguer, C.

2009-01-01

This paper deals with a predictive maintenance policy for a continuously deteriorating system subject to stress. We consider a system with two failure mechanisms which are, respectively, due to an excessive deterioration level and a shock. To optimize the maintenance policy of the system, an approach combining statistical process control (SPC) and condition-based maintenance (CBM) is proposed. CBM policy is used to inspect and replace the system according to the observed deterioration level. SPC is used to monitor the stress covariate. In order to assess the performance of the proposed maintenance policy and to minimize the long-run expected maintenance cost per unit of time, a mathematical model for the maintained system cost is derived. Analysis based on numerical results are conducted to highlight the properties of the proposed maintenance policy in respect to the different maintenance parameters

Risk-Based Maintenance Assessment in the Manufacturing Industry: Minimisation of Suboptimal Prioritisation

Directory of Open Access Journals (Sweden)

Ratnayake R.M. Chandima

2017-03-01

Full Text Available Manufacturing firms continuously strive to increase the efficiency and effectiveness in the maintenance management processes. Focus is placed on eliminating the unexpected failures which cause unnecessary costs and the production losses. Risk-based maintenance (RBM strategies enable to address the above through the identification of probability and consequences of potential failures whilst providing a way for prioritisation of maintenance actions based on the risk of possible failures. Such prioritisations enable to identify the optimal maintenance strategy, intervals of maintenance tasks, and optimal level of spare parts inventory. However, the risk assessment activities are performed with the support of a risk matrix. Suboptimal classifications and/or prioritisations arise due to the inherent nature of the risk matrix. This is caused by the fact that there are no means to incorporate actual circumstances at the boundary of the input ranges or at the levels of linguistic data and risk categories. In this paper, a risk matrix is first developed in collaboration with one of the manufacturing firms in Poland. Then, it illustrates the use of fuzzy logic for minimisation of suboptimal prioritisation and/or classifications using a fuzzy inference system (FIS together with illustrative membership functions and a rule base. Finally, an illustrative risk assessment is also demonstrated to illustrate the methodology.

Object and operation supported maintenance for mining equipment

Directory of Open Access Journals (Sweden)

Walter Bartelmus

2014-09-01

Full Text Available The paper aroused in answer to discussion in Mining Magazine (MM September 2011 and July/August 2013. The paper shows that discussion given in the MM issue July/August 2013 does not fulfill expectations expressed in MM issue 2011. The presented paper is the review on maintenance that is based on condition monitoring as tool for detection of faults and failure prevention. Fault and failure are regarded as inevitable during the machine operation as the process of wear and the process of degradation. The question is, if one can influence the wear and degradation process, using condition monitoring. The paper will present technology (in reference to cited papers which demonstrates that the use of the proper method can influence the wear and machine degradation process, using proper condition monitoring techniques and knowing scenarios of wear and degradation process, the maintenance can be rationalized. The presented paper shows possible improvements which are needed to fulfill expectations expressed in MM September 2011 and they are not taken into consideration in MM July/August 3013. These improvements can be fulfilling on the bases of object and operation supported maintenance.

Application and issues of online maintenance for equipment of nuclear power plants

International Nuclear Information System (INIS)

Higasa, Hisakazu

2011-01-01

The maintenance systems for long-term safety and repair costs reduction of equipment of nuclear power plants are stated. Planned maintenance contained the breakdown maintenance (BM) and the preventive maintenance, which consists of the time based maintenance (MBM) and the condition based maintenance (CBM). Explained are the characteristics of equipments, maintenance methods, maintenance solutions and the self-evaluation maintenance power, damage mechanism and solutions, and monitoring tools and application. Stated are the maintenance system and application of monitoring technology, periodical maintenance, application of diagnosis, vibration monitoring techniques, decision of vibration monitoring, and application of monitoring techniques for improvement of maintenance. Illustrated are realization of planned maintenance by reorganization of maintenance, a trend of maintenance of equipments, table of classified maintenance systems, change of maintenance program, maintenance data and investigation of damage mechanism, examples of self-evaluation maintenance power, examples of analysis of damage of parts of equipments, evaluation of rotating machines by vibration method, examples of results of diagnosis of bearing of rotating machines, online maintenance system of Asahi Kasei Engineering Corporation, degradation pattern of pomp, estimation of lifetime by total vibration and vibration on acceleration, and improvement of equipments. (S.Y.)

AIRCRAFT MAINTENANCE HANGAR

Directory of Open Access Journals (Sweden)

GEAMBASU Gabriel George

2017-05-01

Full Text Available The paper presents the maintenance process that is done on an airplane, at a certain period of time, or after a number of flight hours or cycles and describes the checks performed behind each inspection. The first part of research describes the aircraft maintenance process that has to be done after an updated maintenance manual according with aircraft type, followed by a short introduction about maintenance hangar. The second part of the paper presents a hangar design with a foldable roof and walls, which can be folded or extended, over an airplane when a maintenance process is done, or depending on weather condition.

Advanced maintenance research programs

International Nuclear Information System (INIS)

Marston, T.U.; Gelhaus, F.; Burke, R.

1985-01-01

The purpose of this paper is to provide the reader with an idea of the advanced maintenance research program at the Electric Power Research Institute (EPRI). A brief description of the maintenance-related activities is provided as a foundation for the advanced maintenance research projects. The projects can be divided into maintenance planning, preventive maintenance program development and implementation, predictive (or conditional) maintenance, and innovative maintenance techniques. The projects include hardware and software development, human factors considerations, and technology promotion and implementation. The advanced concepts include: the incorporation of artificial intelligence into outage planning; turbine and pump maintenance; rotating equipment monitoring and diagnostics with the aid of expert systems; and the development of mobile robots for nuclear power plant maintenance

Preserved intention maintenance and impaired execution of prospective memory responses in schizophrenia: evidence from an event-based prospective memory study

Directory of Open Access Journals (Sweden)

Gyula eDemeter

2016-04-01

Full Text Available Executive system dysfunction and impaired prospective memory (PM are widely documented in schizophrenia. However, it is not yet clarified which components of PM function are impaired in this disorder. Two plausible target components are the maintenance of delayed intentions and the execution of PM responses. Furthermore, it is debated whether the impaired performance on frequently used executive tasks is associated with deficit in PM functions. The aim of our study was twofold. First, we aimed to investigate the specific processes involved in event-based PM function, mainly focusing on difference between maintenance of intention and execution of PM responses. Second, we aimed to unfold the possible connections between executive functions, clinical symptoms, and PM performance. An event-based PM paradigm was applied with three main conditions: baseline (with no expectation of PM stimuli, and without PM stimuli, expectation condition (participants were told that PM stimuli might occur, though none actually did, and execution condition (participants were told that PM stimuli might occur, and PM stimuli did occur. This procedure allowed us to separately investigate performances associated with intention maintenance and execution of PM responses. We assessed working memory and set-shifting executive functions by memory span tasks and by the Wisconsin Card Sorting Test (WCST, respectively. Twenty patients diagnosed with schizophrenia and 20 healthy control subjects (matched according to age and education took part in the study. It was hypothesized that patients would manifest different levels of performance in the expectation and execution conditions of the PM task. Our results confirmed that the difference between baseline performance and performance in the execution condition (execution cost was significantly larger for participants diagnosed with schizophrenia in comparison with matched healthy control group. However, this difference was not

Managed maintenance, the next step in power plant maintenance

International Nuclear Information System (INIS)

Butterworth, G.; Anderson, T.M.

1984-01-01

The Westinghouse Nuclear Services Integration Division managed maintenance services are described. Essential to the management and control of a total plant maintenance programme is the development of a comprehensive maintenance specification. During recent years Westinghouse has jointly developed total plant engineering-based maintenance specifications with a number of utilities. The process employed and the experience to date are described. To efficiently implement the maintenance programme Westinghouse has developed a computer software program specifically designed for day to day use at the power plant by maintenance personnel. This program retains an equipment maintenance history, schedules maintenance activities, issues work orders and performs a number of sophisticated analyses of the maintenance backlog and forecast, equipment failure rates, etc. The functions of this software program are described and details of Westinghouse efforts to support the utilities in reducing outage times through development of predefined outage plans for critical report maintenance activities are given. Also described is the experience gained in the training of specialized maintenance personnel, employing competency-based training techniques and equipment mock-ups, and the benefits experienced, in terms of improved quality and productivity of maintenance performed. The success experienced with these methods has caused Westinghouse to expand the use of these training techniques to the more routine skill areas of power plant maintenance. A significant reduction in the operating costs of nuclear power plants will only be brought about by a significant improvement in the quality of maintenance. Westinghouse intends to effect this change by expanding its international service capabilities and to make major investments in order to promote technological developments in the area of power plant maintenance. (author)

Preventive Maintenance Interval Prediction: a Spare Parts Inventory Cost and Lost Earning Based Model

Directory of Open Access Journals (Sweden)

O. A. Adebimpe

2015-06-01

Full Text Available In this paper, some preventive maintenance parameters in manufacturing firms were identified and used to develop cost based functions in terms of machine preventive maintenance. The proposed cost based model considers system’s reliability, cost of keeping spare parts inventory and lost earnings in deriving optimal maintenance interval. A case of a manufacturing firm in Nigeria was observed and the data was used to evaluate the model.

Laser-Based Maintenance and Repair Technologies for Reactor Components

International Nuclear Information System (INIS)

Masaki Yoda; Naruhiko Mukai; Makoto Ochiai; Masataka Tamura; Satoshi Okada; Katsuhiko Sato; Motohiko Kimura; Yuji Sano; Noboru Saito; Seishi Shima; Tetsuo Yamamoto

2004-01-01

Toshiba has developed various laser-based maintenance and repair technologies and applied them to existing nuclear power plants. Laser-based technology is considered to be the best tool for remote processing in nuclear power plants, and particularly so for the maintenance and repair of reactor core components. Accessibility could be drastically improved by a simple handling system owing to the absence of reactive force against laser irradiation and the flexible optical fiber. For the preventive maintenance, laser peening (LP) technology was developed and applied to reactor components in operating BWR plants. LP is a novel process to improve residual stress from tensile to compressive on material surface layer by irradiating focused high-power laser pulses in water. We have developed a fiber-delivered LP system as a preventive maintenance measure against stress corrosion cracking (SCC). Laser ultrasonic testing (LUT) has a great potential to be applied to the remote inspection of reactor components. Laser-induced surface acoustic wave (SAW) inspection system was developed using a compact probe with a multi-mode optical fiber and an interferometer. The developed system successfully detected a micro slit of 0.5 mm depth on weld metal and heat-affected zone (HAZ). An artificial SCC was also detected by the system. We are developing a new LP system combined with LUT to treat the inner surface of bottom-mounted instruments (BMI) of PWR plants. Underwater laser seal welding (LSW) technology was also developed to apply surface crack. LSW is expected to isolate the crack tip from corrosive water environment and to stop the propagation of the crack. Rapid heating and cooling of the process minimize the heat effect, which extends the applicability to neutron-irradiated material. This paper describes recent advances in the development and application of such laser-based technologies. (authors)

Risk-Based Operation and Maintenance Using Bayesian Networks

DEFF Research Database (Denmark)

Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

2011-01-01

This paper describes how risk-based decision making can be used for maintenance planning of components exposed to degradation such as fatigue in offshore wind turbines. In fatigue models, large epistemic uncertainties are usually present. These can be reduced if monitoring results are used to upd...

Bayesian based Prognostic Model for Predictive Maintenance of Offshore Wind Farms

DEFF Research Database (Denmark)

Asgarpour, Masoud; Sørensen, John Dalsgaard

2018-01-01

The operation and maintenance costs of offshore wind farms can be significantly reduced if existing corrective actions are performed as efficient as possible and if future corrective actions are avoided by performing sufficient preventive actions. In this paper a prognostic model for degradation...... monitoring, fault prediction and predictive maintenance of offshore wind components is defined. The diagnostic model defined in this paper is based on degradation, remaining useful lifetime and hybrid inspection threshold models. The defined degradation model is based on an exponential distribution...

Bayesian based Prognostic Model for Predictive Maintenance of Offshore Wind Farms

DEFF Research Database (Denmark)

Asgarpour, Masoud; Sørensen, John Dalsgaard

2018-01-01

monitoring, fault prediction and predictive maintenance of offshore wind components is defined. The diagnostic model defined in this paper is based on degradation, remaining useful lifetime and hybrid inspection threshold models. The defined degradation model is based on an exponential distribution......The operation and maintenance costs of offshore wind farms can be significantly reduced if existing corrective actions are performed as efficient as possible and if future corrective actions are avoided by performing sufficient preventive actions. In this paper a prognostic model for degradation...

Bayesian based Prognostic Model for Predictive Maintenance of Offshore Wind Farms

DEFF Research Database (Denmark)

Asgarpour, Masoud

2017-01-01

monitoring, fault detection and predictive maintenance of offshore wind components is defined. The diagnostic model defined in this paper is based on degradation, remaining useful lifetime and hybrid inspection threshold models. The defined degradation model is based on an exponential distribution......The operation and maintenance costs of offshore wind farms can be significantly reduced if existing corrective actions are performed as efficient as possible and if future corrective actions are avoided by performing sufficient preventive actions. In this paper a prognostic model for degradation...

Developing optimized prioritizing road maintenance

Directory of Open Access Journals (Sweden)

Ewadh Hussein Ali

2018-01-01

Full Text Available Increased demand for efficient maintenance of the existing roadway system needs optimal usage of the allocated funds. The paper demonstrates optimized methods for prioritizing maintenance implementation projects. A selected zone of roadway system in Kerbala city represents the study area to demonstrate the application of the developed prioritization process. Paver system PAVER integrated with GIS is used to estimate and display the pavement condition index PCI, thereby to establish a priority of maintenance. In addition to simple ranking method by PCI produced by the output of PAVER, the paper introduces PCI measure for each section of roadway. The paper introduces ranking by multiple measures investigated through expert knowledge about measures that affect prioritization and their irrespective weights due to a predesigned questionnaire. The maintenance priority index (MPI is related to cost of suitable proposed maintenance, easiness of proposed maintenance, average daily traffic and functional classification of the roadway in addition to PCI. Further, incremental benefit-cost analysis ranking provide an optimized process due to benefit and cost of maintenance. The paper introduces efficient display of layout and ranking for the selected zone of roadway system based on MPI index and incremental BCR method. Although the two developed methods introduce different layout display for priority, statistical test shows that no significant difference between ranking of all methods of prioritization.

Lead particle size and its association with firing conditions and range maintenance: implications for treatment.

Science.gov (United States)

Dermatas, Dimitris; Chrysochoou, Maria

2007-08-01

Six firing range soils were analyzed, representing different environments, firing conditions, and maintenance practices. The particle size distribution and lead (Pb) concentration in each soil fraction were determined for samples obtained from the backstop berms. The main factors that were found to influence Pb fragment size were the type of soil used to construct the berms and the type of weapon fired. The firing of high velocity weapons, i.e., rifles, onto highly angular soils induced significant fragmentation of the bullets and/or pulverization of the soil itself. This resulted in the accumulation of Pb in the finer soil fractions and the spread of Pb contamination beyond the vicinity of the backstop berm. Conversely, the use of clay as backstop and the use of low velocity pistols proved to be favorable for soil clean-up and range maintenance, since Pb was mainly present as large metallic fragments that can be recovered by a simple screening process. Other factors that played important roles in Pb particle size distribution were soil chemistry, firing distance, and maintenance practices, such as the use of water spray for dust suppression and deflectors prior to impact. Overall, coarse Pb particles provide much easier and more cost-effective maintenance, soil clean-up, and remediation via physical separation. Fine Pb particles release Pb more easily, pose an airborne Pb hazard, and require the application of stabilization/solidification treatment methods. Thus, to ensure sustainable firing range operations by means of cost-effective design, maintenance, and clean-up, especially when high velocity weapons are used, the above mentioned factors should be carefully considered.

A preventive maintenance policy based on dependent two-stage deterioration and external shocks

International Nuclear Information System (INIS)

Yang, Li; Ma, Xiaobing; Peng, Rui; Zhai, Qingqing; Zhao, Yu

2017-01-01

This paper proposes a preventive maintenance policy for a single-unit system whose failure has two competing and dependent causes, i.e., internal deterioration and sudden shocks. The internal failure process is divided into two stages, i.e. normal and defective. Shocks arrive according to a non-homogeneous Poisson process (NHPP), leading to the failure of the system immediately. The occurrence rate of a shock is affected by the state of the system. Both an age-based replacement and finite number of periodic inspections are schemed simultaneously to deal with the competing failures. The objective of this study is to determine the optimal preventive replacement interval, inspection interval and number of inspections such that the expected cost per unit time is minimized. A case study on oil pipeline maintenance is presented to illustrate the maintenance policy. - Highlights: • A maintenance model based on two-stage deterioration and sudden shocks is developed. • The impact of internal system state on external shock process is studied. • A new preventive maintenance strategy combining age-based replacements and periodic inspections is proposed. • Postponed replacement of a defective system is provided by restricting the number of inspections.

Optimization of the preventive maintenance plan of a series components system

Energy Technology Data Exchange (ETDEWEB)

Duarte, Jose A. Caldeira [Mathematical Department, Instituto Politecnico de Setubal/Escola Superior de Tecnologia de Setubal, Campus do IPS, Estefanilha, 2914-508 Setubal (Portugal)]. E-mail: jduarte@est.ips.pt; Craveiro, Joao C. Taborda A. [MIIT, Manutencao Industrial Informatizada e Tecnologia, Lda, Av. Elias Garcia, 123, 5o, Lisbon (Portugal); Trigo, Tomas Pedro [MIIT, Manutencao Industrial Informatizada e Tecnologia, Lda, Av. Elias Garcia, 123, 5o, Lisbon (Portugal)

2006-04-15

One of the most critical problems in preventive maintenance is the determination of the optimum frequency to perform preventive maintenance in equipment, in order to ensure its availability. In this paper, we propose an algorithm to solve the previous problem for equipment that exhibit linearly increasing hazard rate and constant repair rate. Based on this algorithm, we have developed another one to solve the problem of maintenance management of a series system based on preventive maintenance over the different system components. We assume that all components of the system still exhibit linearly increasing hazard rate and constant repair rate and that preventive maintenance would bring the system to the as good as new condition. We define a cost function for maintenance tasks (preventive and corrective) for the system. The algorithm calculates the interval of time between preventive maintenance actions for each component, minimizing the costs, and in such a way that the total downtime, in a certain period of time, does not exceed a predetermined value.

Performance based regulation - The maintenance rule

Energy Technology Data Exchange (ETDEWEB)

Correia, Richard P. [NRR/DOTS/TQMP, U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, M/S OWFN 10A19, Washington, D.C. 20555 (United States)

1997-07-01

The U.S. Nuclear Regulatory Commission has begun a transition from 'process-oriented' to 'results-oriented' regulations. The maintenance rule is a results-oriented rule that mandates consideration of risk and plant performance. The Maintenance Rule allows licensees to devise the most effective and efficient means of achieving the results described in the rule including the use of Probabilistic Risk (or Safety) Assessments. The NRC staff conducted a series of site visits to evaluate implementation of the Rule. Conclusions from the site visits indicated that the results-oriented Maintenance Rule can be successfully implemented and enforced. (author)

Performance based regulation - The maintenance rule

International Nuclear Information System (INIS)

Correia, Richard P.

1997-01-01

The U.S. Nuclear Regulatory Commission has begun a transition from 'process-oriented' to 'results-oriented' regulations. The maintenance rule is a results-oriented rule that mandates consideration of risk and plant performance. The Maintenance Rule allows licensees to devise the most effective and efficient means of achieving the results described in the rule including the use of Probabilistic Risk (or Safety) Assessments. The NRC staff conducted a series of site visits to evaluate implementation of the Rule. Conclusions from the site visits indicated that the results-oriented Maintenance Rule can be successfully implemented and enforced. (author)

AN OPTIMAL MAINTENANCE MANAGEMENT MODEL FOR AIRPORT CONCRETE PAVEMENT

Science.gov (United States)

Shimomura, Taizo; Fujimori, Yuji; Kaito, Kiyoyuki; Obama, Kengo; Kobayashi, Kiyoshi

In this paper, an optimal management model is formulated for the performance-based rehabilitation/maintenance contract for airport concrete pavement, whereby two types of life cycle cost risks, i.e., ground consolidation risk and concrete depreciation risk, are explicitly considered. The non-homogenous Markov chain model is formulated to represent the deterioration processes of concrete pavement which are conditional upon the ground consolidation processes. The optimal non-homogenous Markov decision model with multiple types of risk is presented to design the optimal rehabilitation/maintenance plans. And the methodology to revise the optimal rehabilitation/maintenance plans based upon the monitoring data by the Bayesian up-to-dating rules. The validity of the methodology presented in this paper is examined based upon the case studies carried out for the H airport.

Artificial Intelligent Platform as Decision Tool for Asset Management, Operations and Maintenance.

Science.gov (United States)

2018-01-04

An Artificial Intelligence (AI) system has been developed and implemented for water, wastewater and reuse plants to improve management of sensors, short and long term maintenance plans, asset and investment management plans. It is based on an integrated approach to capture data from different computer systems and files. It adds a layer of intelligence to the data. It serves as a repository of key current and future operations and maintenance conditions that a plant needs have knowledge of. With this information, it is able to simulate the configuration of processes and assets for those conditions to improve or optimize operations, maintenance and asset management, using the IViewOps (Intelligent View of Operations) model. Based on the optimization through model runs, it is able to create output files that can feed data to other systems and inform the staff regarding optimal solutions to the conditions experienced or anticipated in the future.

Maintenance management of railway infrastructures based on reliability analysis

International Nuclear Information System (INIS)

Macchi, Marco; Garetti, Marco; Centrone, Domenico; Fumagalli, Luca; Piero Pavirani, Gian

2012-01-01

Railway infrastructure maintenance plays a crucial role for rail transport. It aims at guaranteeing safety of operations and availability of railway tracks and related equipment for traffic regulation. Moreover, it is one major cost for rail transport operations. Thus, the increased competition in traffic market is asking for maintenance improvement, aiming at the reduction of maintenance expenditures while keeping the safety of operations. This issue is addressed by the methodology presented in the paper. The first step of the methodology consists of a family-based approach for the equipment reliability analysis; its purpose is the identification of families of railway items which can be given the same reliability targets. The second step builds the reliability model of the railway system for identifying the most critical items, given a required service level for the transportation system. The two methods have been implemented and tested in practical case studies, in the context of Rete Ferroviaria Italiana, the Italian public limited company for railway transportation.

PREVENTIVE MAINTENANCE. HONEYWELL PLANNING GUIDE.

Science.gov (United States)

Honeywell, Inc., Minneapolis, Minn.

THIS HONEYWELL PAMPHLET DISCUSSES SOME ASPECTS OF PREVENTIVE MAINTENANCE OF AUTOMATIC CONTROLS, HEATING, VENTILATING, AND AIR CONDITIONING, AND COMPARES IN-PLANT WITH CONTRACT SERVICE, CONCLUDING THAT CONTRACT SERVICE IS PREFERABLE AND DESCRIBING A NUMBER OF MAINTENANCE PLANS WHICH THEY FURNISH. PREVENTIVE MAINTENANCE PROVIDES--(1) MORE EFFICIENT…

14 CFR 119.47 - Maintaining a principal base of operations, main operations base, and main maintenance base...

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Maintaining a principal base of operations, main operations base, and main maintenance base; change of address. 119.47 Section 119.47 Aeronautics... Under Part 121 or Part 135 of This Chapter § 119.47 Maintaining a principal base of operations, main...

Optimizing Maintenance of Constraint-Based Database Caches

Science.gov (United States)

Klein, Joachim; Braun, Susanne

Caching data reduces user-perceived latency and often enhances availability in case of server crashes or network failures. DB caching aims at local processing of declarative queries in a DBMS-managed cache close to the application. Query evaluation must produce the same results as if done at the remote database backend, which implies that all data records needed to process such a query must be present and controlled by the cache, i. e., to achieve “predicate-specific” loading and unloading of such record sets. Hence, cache maintenance must be based on cache constraints such that “predicate completeness” of the caching units currently present can be guaranteed at any point in time. We explore how cache groups can be maintained to provide the data currently needed. Moreover, we design and optimize loading and unloading algorithms for sets of records keeping the caching units complete, before we empirically identify the costs involved in cache maintenance.

PRM-based patterns for knowledge formalisation of industrial systems to support maintenance strategies assessment

International Nuclear Information System (INIS)

Medina-Oliva, G.; Weber, P.; Iung, B.

2013-01-01

The production system and its maintenance system must be now developed on “system thinking” paradigm in order to guarantee that Key Performance Indicators (KPI) will be optimized all along the production system (operation) life. In a recursive way, maintenance system engineering has to integrate also KPI considerations with regards to its own enabling systems. Thus this paper develops a system-based methodology wherein a set of KPIs is computed in order to verify if the objectives of the production and maintenance systems are satisfied. In order to help the decision-making process for maintenance managers, a “unified” generic model have been developed. This model integrates (a) the interactions of the maintenance system with its enabling systems, (b) the impact of the maintenance strategies through the computation of some key performance indicators, and (c) different kinds of knowledge regarding the maintenance system and the system of interest, including quantitative and qualitative knowledge. This methodology is based on an executable unified model built with Probabilistic Relational Model (PRM). PRM allows a modular representation and inferences computation of large size models. The methodology added-value is shown on a test-bench

Managing wind turbine reliability and maintenance via performance-based contract

DEFF Research Database (Denmark)

Jin, Tongdan; Ding, Yi; Guo, Huairui

2012-01-01

between system cost, reliability and spare parts stocking. This analytical insight into the system performance allows the turbine manufacturer to optimize design, production, and after-sales services. The study aims to create a theoretical basis to facilitate the transition of the maintenance paradigm......Performance-based contracting (PBC) is reshaping the acquisition, operation, and maintenance of capital equipment. Under the PBC scheme, we propose a holistic approach for lowering the cost of wind turbine ownership while meeting the availability requirement. Our effects are focused on integrated...... firms who design and market wind turbines, and also provide maintenance and repair service. PBC differs from conventional service contracts in that the wind farmers compensate the service provider for the system performance, not the spare parts and repair labor. We explore the analytical relationship...

Analyzing maintenance strategies by agent-based simulations: A feasibility study

International Nuclear Information System (INIS)

Kaegi, M.; Mock, R.; Kroeger, W.

2009-01-01

Thoroughly planned and implemented maintenance strategies save time and cost. However, the integration of maintenance work into reliability analysis is difficult as common modeling techniques are often not applicable due to state explosion which calls for restrictive model assumptions and oversimplification. From authors' point of view, agent-based modeling (ABM) of technical and organizational systems is a promising approach to overcome such problems. But since ABM is not well established in reliability analysis its feasibility in this area still has to be demonstrated. For this purpose ABM is compared with Markov chains, namely by analyzing the reliability of a maintained n-unit system with dependent repair events, applying both modeling approaches. Although ABM and Markov chains lead to the same numerical results, the former points out the potentiality of an improved system state handling. This is demonstrated by extending the ABM with operators as additional 'agents' featuring their location (x;y) availability (0;1) and different maintenance strategies. This extension highlights the capability of ABM to analyze complex emergent system behavior and allows a systematic refinement and optimization of the maintenance strategies.

Risk Based Maintenance of Offshore Wind Turbines Using Bayesian Networks

DEFF Research Database (Denmark)

Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

2010-01-01

This paper presents how Bayesian networks can be used to make optimal decisions for repairs of offshore wind turbines. The Bayesian network is an efficient tool for updating a deterioration model whenever new information becomes available from inspections/monitoring. The optimal decision is found...... such that the preventive maintenance effort is balanced against the costs to corrective maintenance including indirect costs to reduced production. The basis for the optimization is the risk based Bayesian decision theory. The method is demonstrated through an application example....

On the use of on-line detection for maintenance of gradually deteriorating systems

International Nuclear Information System (INIS)

Fouladirad, Mitra; Grall, Antoine; Dieulle, Laurence

2008-01-01

This paper deals with condition-based maintenance and non-stationary degradation process due to sudden changes. This is an attempt to propose an adaptive maintenance policy based on the on-line change detection procedure which can help to detect switches from a nominal mode to an accelerated mode in a non-informative context about the change mode time

On the use of on-line detection for maintenance of gradually deteriorating systems

Energy Technology Data Exchange (ETDEWEB)

Fouladirad, Mitra [Institut Charles Delaunay, Universite de Technologie de Troyes, FRE CNRS 2848, LM2S 12 rue Marie Curie, 10010 Troyes (France); Grall, Antoine [Institut Charles Delaunay, Universite de Technologie de Troyes, FRE CNRS 2848, LM2S 12 rue Marie Curie, 10010 Troyes (France)], E-mail: antoine.grall@utt.fr; Dieulle, Laurence [Institut Charles Delaunay, Universite de Technologie de Troyes, FRE CNRS 2848, LM2S 12 rue Marie Curie, 10010 Troyes (France)

2008-12-15

This paper deals with condition-based maintenance and non-stationary degradation process due to sudden changes. This is an attempt to propose an adaptive maintenance policy based on the on-line change detection procedure which can help to detect switches from a nominal mode to an accelerated mode in a non-informative context about the change mode time.

TECHNICAL MAINTENANCE EFFICIENCY OF THE AIRCRAFT MAINTENANCE-FREE ON-BOARD SYSTEM BETWEEN SCHEDULED MAINTENANCES

Directory of Open Access Journals (Sweden)

A. M. Bronnikov

2017-01-01

Full Text Available The avionics concept of the maintenance-free on-board equipment implies the absence of necessity to maintain onboard systems between scheduled maintenance, preserving the required operational and technical characteristics; it should be achieved by automatic diagnosis of the technical condition and the application of active means of ensuring a failsafe design, allowing to change the structure of the system to maintain its functions in case of failure. It is supposed that such equipment will reduce substantially and in the limit eliminate traditional maintenance of aircraft between scheduled maintenance, ensuring maximum readiness for use, along with improving safety. The paper proposes a methodology for evaluating the efficiency of maintenance-free between scheduled maintenance aircraft system with homogeneous redundancy. The excessive redundant elements allow the system to accumulate failures which are repaired during the routine maintenance. If the number of failures of any reserve is approaching a critical value, the recovery of the on-board system (elimination of all failures is carried out between scheduled maintenance by conducting rescue and recovery operations. It is believed that service work leads to the elimination of all failures and completely updates the on-board system. The process of system operational status changes is described with the discrete-continuous model in the flight time. The average losses in the sorties and the average cost of operation are used as integrated efficiency indicators of system operation. For example, the evaluation of the operation efficiency of formalized on-board system with homogeneous redundancy demonstrates the efficiency of the proposed methodology and the possibility of its use while analyzing the efficiency of the maintenance-free operation equipment between scheduled periods. As well as a comparative analysis of maintenance-free operation efficiency of the on-board system with excessive

State of technology, system and solution supporting on-line maintenance - company's activities and products

International Nuclear Information System (INIS)

Nishitani, Junichi; Shimizu, Shunichi; Higasa, Hisakazu

2010-01-01

The new inspection system based on operator's maintenance and monitoring program of nuclear power plants was introduced in Japan more than one year ago and recommended on-line maintenance (maintenance during operation) will be carried out to increase capacity factor with safe and reliable operation of the plant. In this feature article, nine experts described the state of technology, system and solution supporting on-line maintenance - company's activities and products. These were titled as 'MHI's technology supporting on-line maintenance'. 'Technology supporting on-line maintenance - Toshiba's activities to upgrade monitoring and diagnostic service and maintenance management', 'AsahiKASEI's activities of on-line maintenance', 'Importance of information sharing of on-line maintenance and its ideal method-function of impact plan of IBM Maximo Asset Management for Nuclear', 'US's on-line maintenance and information systems', 'SmartProcedures realizing safe operation of nuclear power plant - proposal of computerized procedures', 'Ultrasonic leak detection system SDT170', 'Application of infrared thermography for equipment maintenance in nuclear power plant' and 'On-line condition monitoring system - condition eye'. (T. Tanaka)

Using stationary image based data collection method for evaluation of traffic sign condition

Directory of Open Access Journals (Sweden)

Majid Khalilikhah

2016-12-01

Full Text Available Transportation asset management helps monitor the transportation systems and optimize the construction, operation, and maintenance of assets. Many state Department of Transportations (DOTs have already established asset management systems for high cost and low quantity assets, e.g., bridge and tunnel assets. However, due to the sheer number of traffic signs deployed by DOTs, statewide sign inventory and condition information are not well developed. Currently, using handheld devices is the most selected method by agencies to measure signs. To address safety challenge and high cost of data collection, an innovative stationary image based method has recently been proposed. This paper discusses the advantages and disadvantages of such image based method over using handheld devices in terms of the accuracy, possibility and consistency of data, speed, safety, maintenance, and cost. At its completion, this study provides suggestions to tackle the issues associated with image based method.

Laboratory equipment maintenance contracts.

Science.gov (United States)

Boudreau, D A; Scheer, W D; Catrou, P G

1985-12-01

The increasing level of technical sophistication and complexity found in clinical laboratory instrumentation today more than ever demands careful attention to maintenance service needs. The time-worn caution for careful definition of requirements for acquisition of a system should also carry over to acquisition of maintenance service. Guidelines are presented for specifications of terms and conditions for maintenance service from the perspective of the laboratorian in the automated clinical laboratory.

Excellence through maintenance mastering

International Nuclear Information System (INIS)

Lamarche, M.; Guillot, M.; Monier, M.

1987-01-01

To improve the overall availability factor of nuclear power plants you have to cut either the forced outage role and the planned outage time or you need to reduce simultaneously the failures and the efforts devoted to avoiding them. Among other results, this goal leads to a decrease in the number of real or anticipated problems. Electricite de France policy, in this matter, is to focus on decreasing the compoents' maintenance needs through a comprehensive modification program, targeted to eliminating the weak points as revealed by the operation. Thereby one may reach, for simple equipment, a nearly maintenance-free condition in which the only maintenance needed is surveillance, which provides assurance that everything is operating properly. A good example of this type of equipment is the family of static components, drums, and pipes whose corrective maintenance is almost nil when their initial condition is good

Condition Monitoring for DC-link Capacitors Based on Artificial Neural Network Algorithm

DEFF Research Database (Denmark)

Soliman, Hammam Abdelaal Hammam; Wang, Huai; Gadalla, Brwene Salah Abdelkarim

2015-01-01

hardware will reduce the cost, and therefore could be more promising for industry applications. A condition monitoring method based on Artificial Neural Network (ANN) algorithm is therefore proposed in this paper. The implementation of the ANN to the DC-link capacitor condition monitoring in a back......In power electronic systems, capacitor is one of the reliability critical components . Recently, the condition monitoring of capacitors to estimate their health status have been attracted by the academic research. Industry applications require more reliable power electronics products...... with preventive maintenance. However, the existing capacitor condition monitoring methods suffer from either increased hardware cost or low estimation accuracy, being the challenges to be adopted in industry applications. New development in condition monitoring technology with software solutions without extra...

A method for accounting for maintenance costs in flux balance analysis improves the prediction of plant cell metabolic phenotypes under stress conditions.

Science.gov (United States)

Cheung, C Y Maurice; Williams, Thomas C R; Poolman, Mark G; Fell, David A; Ratcliffe, R George; Sweetlove, Lee J

2013-09-01

Flux balance models of metabolism generally utilize synthesis of biomass as the main determinant of intracellular fluxes. However, the biomass constraint alone is not sufficient to predict realistic fluxes in central heterotrophic metabolism of plant cells because of the major demand on the energy budget due to transport costs and cell maintenance. This major limitation can be addressed by incorporating transport steps into the metabolic model and by implementing a procedure that uses Pareto optimality analysis to explore the trade-off between ATP and NADPH production for maintenance. This leads to a method for predicting cell maintenance costs on the basis of the measured flux ratio between the oxidative steps of the oxidative pentose phosphate pathway and glycolysis. We show that accounting for transport and maintenance costs substantially improves the accuracy of fluxes predicted from a flux balance model of heterotrophic Arabidopsis cells in culture, irrespective of the objective function used in the analysis. Moreover, when the new method was applied to cells under control, elevated temperature and hyper-osmotic conditions, only elevated temperature led to a substantial increase in cell maintenance costs. It is concluded that the hyper-osmotic conditions tested did not impose a metabolic stress, in as much as the metabolic network is not forced to devote more resources to cell maintenance. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Condition Monitoring for Roller Bearings of Wind Turbines Based on Health Evaluation under Variable Operating States

Directory of Open Access Journals (Sweden)

Lei Fu

2017-10-01

Full Text Available Condition monitoring (CM is used to assess the health status of wind turbines (WT by detecting turbine failure and predicting maintenance needs. However, fluctuating operating conditions cause variations in monitored features, therefore increasing the difficulty of CM, for example, the frequency-domain analysis may lead to an inaccurate or even incorrect prediction when evaluating the health of the WT components. In light of this challenge, this paper proposed a method for the health evaluation of WT components based on vibration signals. The proposed approach aimed to reduce the evaluation error caused by the impact of the variable operating condition. First, the vibration signal was decomposed into a set of sub-signals using variational mode decomposition (VMD. Next, the sub-signal energy and the probability distribution were obtained and normalized. Finally, the concept of entropy was introduced to evaluate the health condition of a monitored object to provide an effective guide for maintenance. In particular, the health evaluation for CM was based on a performance review over a range of operating conditions, rather than at a certain single operating condition. Experimental investigations were performed which verified the efficiency of the evaluation method, as well as a comparison with the previous method.

Maintenance of nuclear medicine instruments

Energy Technology Data Exchange (ETDEWEB)

Ambro, P

1993-12-31

Maintenance of instruments is generally of two kinds: (a) corrective maintenance, on a non-scheduled basis, to restore equipment to a functional status by repairs; (b) preventive maintenance, to keep equipment in a specified functional condition by providing systematic inspection, quality control, detection and correction of early malfunctions. Most of the instruments used in nuclear medicine are rather complex systems built from mechanical, electrical and electronic parts. Any one of these components is liable to fail at some time or other. Repair could be done only by a specialist who is able to evaluate the condition of the various parts ranging from cables to connectors, from scintillators to photomultipliers, from microprocessors to microswitches. The knowledge of the intricacies of the various electronic components required for their repairs is quite wide and varied. The electronics industry turns out more and more multi-purpose chips which can carry out the functions of many parts used in the instruments of the earlier generation. This provides protection against unauthorized copying of the circuits but it serves another purpose as well of inhibiting repairs by non-factory personnel. These trends of the instrument design should be taken into consideration when a policy has to be developed for the repairs of the hospital based equipment 1 fig., 1 tab

Maintenance of nuclear medicine instruments

International Nuclear Information System (INIS)

Ambro, P.

1992-01-01

Maintenance of instruments is generally of two kinds: (a) corrective maintenance, on a non-scheduled basis, to restore equipment to a functional status by repairs; (b) preventive maintenance, to keep equipment in a specified functional condition by providing systematic inspection, quality control, detection and correction of early malfunctions. Most of the instruments used in nuclear medicine are rather complex systems built from mechanical, electrical and electronic parts. Any one of these components is liable to fail at some time or other. Repair could be done only by a specialist who is able to evaluate the condition of the various parts ranging from cables to connectors, from scintillators to photomultipliers, from microprocessors to microswitches. The knowledge of the intricacies of the various electronic components required for their repairs is quite wide and varied. The electronics industry turns out more and more multi-purpose chips which can carry out the functions of many parts used in the instruments of the earlier generation. This provides protection against unauthorized copying of the circuits but it serves another purpose as well of inhibiting repairs by non-factory personnel. These trends of the instrument design should be taken into consideration when a policy has to be developed for the repairs of the hospital based equipment

Concept design of CFETR superconducting magnet system based on different maintenance ports

International Nuclear Information System (INIS)

Zheng, Jinxing; Liu, Xufeng; Song, Yuntao; Wan, Yuanxi; Li, Jiangang; Wu, Sontao; Wan, Baonian; Ye, Minyou; Wei, Jianghua; Xu, Weiwei; Liu, Sumei; Weng, Peide; Lu, Kun; Luo, Zhengping

2013-01-01

Highlights: • This article discussed the concept design of the magnet system of CFETR based on different maintenance port cases. • The major and minor radius of plasma is 5.7 m and 1.6 m, and the central magnetic field was designed as 4.5/5.0 T. • The different maintenance ports design have little impact on the design of TF and CS coils’ design, but have certain impact on the PF coils’ design. -- Abstract: CFETR which stands for “China Fusion Engineering Test Reactor” is a new tokamak device. Its magnet system includes the Toroidal Field (TF) winding, Center solenoid winding (CS) and Poloidal Field (PF) winding. The main goal of the project is to build a fusion engineering Tokamak reactor with its fusion power is 50–200 MW and should be self-sufficiency by blanket. In order to ensure the maintenance ports design and maintenance method, this article discussed the concept design of the magnet system based on different maintenance port cases. The paper detailed studied the magnet system of CFETR including the electromagnetic analysis and parameters for TF (CS)PF. Besides, the volt-seconds of ohmic field are presented as detailed as possible in this paper. In addition, the calculations and optimizations of equilibrium field which should guarantee the plasma discharge of single null shape is carried out. The design work reported here illustrates that the present maintenance ports will not have a great impact on the design of the magnet system. The concept design of the magnet system can meet the requirement of the physical target

An overview of the recent advances in delay-time-based maintenance modelling

International Nuclear Information System (INIS)

Wang, Wenbin

2012-01-01

Industrial plant maintenance is an area which has enormous potential to be improved. It is also an area attracted significant attention from mathematical modellers because of the random phenomenon of plant failures. This paper reviews the recent advances in delay-time-based maintenance modelling, which is one of the mathematical techniques for optimising inspection planning and related problems. The delay-time is a concept that divides a plant failure process into two stages: from new until the point of an identifiable defect, and then from this point to failure. The first stage is called the normal working stage and the second stage is called the failure delay-time stage. If the distributions of the two stages can be quantified, the relationship between the number of failures and the inspection interval can be readily established. This can then be used for optimizing the inspection interval and other related decision variables. In this review, we pay particular attention to new methodological developments and industrial applications of the delay-time-based models over the last few decades. The use of the delay-time concept and modeling techniques in other areas rather than in maintenance is also reviewed. Future research directions are also highlighted. - Highlights: ► Reviewed the recent advances in delay-time-based maintenance models and applications. ► Compared the delay-time-based models with other models. ► Focused on methodologies and applications. ► Pointed out future research directions.

Study on risk indicator for appropriate plant maintenance considering aging effect

International Nuclear Information System (INIS)

Mano, Akihiro; Yamaguchi, Akira; Takata, Takashi

2014-01-01

Since, nuclear power plants run for a long term and plant component may deteriorate due to aging, plant safety must be maintained through maintenance activities of components. The maintenance will become more important as the number of aged plant increases. In the planning of maintenance, one must select appropriate components and interval. In general, Fussell-Vesely importance (FV) and Risk Achievement Worth (RAW) are used as a risk indicator for the maintenance. A priority order of each component can be evaluated using those risk indicators at a certain condition. However, the influence of aging (time history) on the order cannot be estimated directly. In the paper, a change of conditional core damage probability (ΔCCDP) and a change of conditional containment failure probability (ΔCCFP) are proposed as additional indicators in which the aging effect is evaluated directly so as to determine the priority order. A simplified level one probabilistic risk assessment (PRA) has been carried out in order to investigate the change of the risk indicators by considering the change of a component failure probability due to aging. In the analyses, three conditions are assumed; base (original) state, aging state and further aging state without maintenance activities. It is demonstrated that the proposed indicator (ΔCCDP and ΔCCFP) reveals the aging effect of each component, while the change of the FV and RAW represent unrealistic behavior through the states. As a result, it is found that the ΔCCDP and ΔCCFP are superior to the others in terms of the ability to evaluate components appropriately in deteriorated (aging) states and take account of differences of deterioration behavior. It is also found that the priority order of the multiple-components maintenance at the same time can also be evaluated using the ΔCCDP and ΔCCFP. Additionally, a risk informed decision making based on the risk acceptance criteria can be discussed for the maintenance procedure using the

Manipulator techniques and problems of their application in primary circuit maintenance

International Nuclear Information System (INIS)

Kertscher, F.; Popp, P.

1985-01-01

The fundamental structure and specifications of manipulators (in particular of industrial robots) are presented in order to derive the application conditions and fields for manipulators in primary circuit maintenance. The necessity of applying process-specific manipulator technique in the primary circuit maintenance is based on nuclear safety requirements and on decreasing of the radiation exposure of maintenance personnel. Synchronous manipulators and industrial robots are the types of manipulators used in materials testing, repairing and scrapping. The technical requirements of manipulators are discussed

An evaluation of the Browns Ferry Nuclear Plant preventive maintenance program based on reliability centered maintenance analysis

International Nuclear Information System (INIS)

McCullough, C.L.; McCullough, C.A.

1989-01-01

Reliability centered maintenance (RCM) techniques were used to support a preventative maintenance (PM) upgrade program (PMUP) performed at TVA Browns Ferry Nuclear Plant (BFNP). The purpose of the RCM analysis was to identify critical equipment based on risk and economic importance and to evaluate the PM activities applicable to that equipment. The analysis may be conveniently divided into three steps, which will be outlined in the Approach section of this paper. The net benefit of the RCM approach was a prioritization of the focus of the PM upgrade program so that plant components receive attention proportional to their importance, and assurance that PM activities properly address the most likely component failure causes

Maintenance of algal endosymbionts in Paramecium bursaria: a simple model based on population dynamics.

Science.gov (United States)

Iwai, Sosuke; Fujiwara, Kenji; Tamura, Takuro

2016-09-01

Algal endosymbiosis is widely distributed in eukaryotes including many protists and metazoans, and plays important roles in aquatic ecosystems, combining phagotrophy and phototrophy. To maintain a stable symbiotic relationship, endosymbiont population size in the host must be properly regulated and maintained at a constant level; however, the mechanisms underlying the maintenance of algal endosymbionts are still largely unknown. Here we investigate the population dynamics of the unicellular ciliate Paramecium bursaria and its Chlorella-like algal endosymbiont under various experimental conditions in a simple culture system. Our results suggest that endosymbiont population size in P. bursaria was not regulated by active processes such as cell division coupling between the two organisms, or partitioning of the endosymbionts at host cell division. Regardless, endosymbiont population size was eventually adjusted to a nearly constant level once cells were grown with light and nutrients. To explain this apparent regulation of population size, we propose a simple mechanism based on the different growth properties (specifically the nutrient requirements) of the two organisms, and based from this develop a mathematical model to describe the population dynamics of host and endosymbiont. The proposed mechanism and model may provide a basis for understanding the maintenance of algal endosymbionts. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Maintenance and Outage Management Assessment (MOMA)

International Nuclear Information System (INIS)

2005-01-01

a small team of experienced nuclear experts/specialists in the world. It can be requested for a single area or multiple ones, such as a) In-Service Inspection program review and optimization, including inspection qualification and risk informed inspection, b) maintenance program optimization by means of equipment reliability, performance based approach, risk informed on-line maintenance, condition based maintenance, c) outage improvement be means of streamlined integration of technologies and process, work planning and scheduling, plant modifications and configuration control, indicators and operating experience feedback system, safety culture, outsourcing and contract management, and spare parts

Use of probabilistic risk assessment in maintenance activities at Palo Verde

International Nuclear Information System (INIS)

Lindquist, R.C.; Pobst, D.S.

1993-01-01

Probabilistic risk assessment (PRA) is an important tool in addressing various maintenance activities. At the Palo Verde nuclear generating station (PVNGS), the PRA has been used in a variety of ways to support a wide and diverse selection of maintenance-related activities. For on-line or at-power maintenance, the PRA was used to evaluate combinations of maintenance activities possible with the 12-week or floating maintenance schedule. The maintenance schedule was evaluated to identify any higher risk, undesirable combinations of equipment outages, such as the sole steam-driven auxiliary feedwater pump and the same train emergency diesel generator. Table I is a sampling of the results from the maintenance schedule evaluation in terms of increase in conditional core damage frequency (CDF) above the base- line value due to maintenance on some important key safety systems and combinations thereof. The baseline CDF is 7.4 x 10 -7 per 72 h

The present condition of forest roads as a result of their past maintenance

OpenAIRE

Hribernik, Boštjan; Potočnik, Igor

2006-01-01

Forest roads are built for forest management purposes, to which planning of their use and maintenance is adapted. The increasing importance of non-forestry use of forest roads leads to higher maintenance standard, which by formed maintenance system causes permanent shortage of funds. Higher maintenance costs occur due to the past forest roads construction characteristics, which gave priority to quick opening of villages and farms, on the account of building quality. Other funds expenditure re...

Improving nuclear power plant reliability through predictive maintenance

International Nuclear Information System (INIS)

Geilhausen, R.; Kunze, U.

1996-01-01

Maintenance strategies can be assigned to one of three categories: failure maintenance, periodic maintenance or condition-oriented maintenance. The optimum maintenance scheme can be selected on the basis of a cost-benefit analysis but the safety of life and limb or the political climate for NPP can hardly expressed in numbers. The implementation of preventive maintenance needs two preconditions: high-performance instrumentation in the form of stationary and mobile monitoring systems for the determination of the condition of the nuclear power plant components and provision of a tool that can handle both the organization of the work and the evaluation of the results obtained. (authors)

Risk based maintenance to increase safety and decrease costs

International Nuclear Information System (INIS)

Phillips, J.H.

2000-01-01

Risk-Based techniques have been developed for commercial nuclear power plants for the last eight years by a team working through the ASME Center for Research and Technology Development (CRTD). System boundaries and success criteria is defined using the Probabilistic Risk Analysis or Probabilistic Safety Analysis developed to meet the Individual Plant Evaluation. Final ranking of components is by a plant expert panel similar to the one developed for the Maintenance Rule. Components are identified as being high risk-significant or low risk-significant. Maintenance and resources are focused on those components that have the highest risk-significance. The techniques have been developed and applied at a number of plants. Results from the first risk-based inspection pilot plant indicates safety due to pipe failure can be doubled while the inspection reduced to about 80% when compared with current inspection programs. Pilot studies on risk-based testing indicate that about 60% of pumps and 25 to 30% of valves in plants are high safety-significant The reduction in inspection and testing reduces the person-rem exposure and resulting in further increases in safety. These techniques have been documented in publications by the ASME CRTD which are referenced. (author)

A Fuzzy analytical hierarchy process approach in irrigation networks maintenance

Science.gov (United States)

Riza Permana, Angga; Rintis Hadiani, Rr.; Syafi'i

2017-11-01

Ponorogo Regency has 440 Irrigation Area with a total area of 17,950 Ha. Due to the limited budget and lack of maintenance cause decreased function on the irrigation. The aim of this study is to make an appropriate system to determine the indices weighted of the rank prioritization criteria for irrigation network maintenance using a fuzzy-based methodology. The criteria that are used such as the physical condition of irrigation networks, area of service, estimated maintenance cost, and efficiency of irrigation water distribution. 26 experts in the field of water resources in the Dinas Pekerjaan Umum were asked to fill out the questionnaire, and the result will be used as a benchmark to determine the rank of irrigation network maintenance priority. The results demonstrate that the physical condition of irrigation networks criterion (W1) = 0,279 has the greatest impact on the assessment process. The area of service (W2) = 0,270, efficiency of irrigation water distribution (W4) = 0,249, and estimated maintenance cost (W3) = 0,202 criteria rank next in effectiveness, respectively. The proposed methodology deals with uncertainty and vague data using triangular fuzzy numbers, and, moreover, it provides a comprehensive decision-making technique to assess maintenance priority on irrigation network.

Improving regulatory oversight of maintenance programs

International Nuclear Information System (INIS)

Cook, S.

2008-01-01

Safe nuclear power plant operation requires that risks due to failure or unavailability of Structures, Systems and Components (SSCs) be minimized. Implementation of an effective maintenance program is a key means for achieving this goal. In its regulatory framework, the important relationship between maintenance and safety is acknowledged by the CNSC. A high level maintenance program requirement is included in the Class I Facilities Regulations. In addition, the operating licence contains a condition based on the principle that the design function and performance of SSCs needs to remain consistent with the plant's design and analysis documents. Nuclear power plant licensees have the primary responsibility for safe operation of their facilities and consequently for implementation of a successful maintenance program. The oversight role of the Canadian Nuclear Safety Commission (CNSC) is to ensure that the licensee carries out that responsibility. The challenge for the CNSC is how to do this consistently and efficiently. Three opportunities for improvement to regulatory maintenance oversight are being pursued. These are related to the regulatory framework, compliance verification inspection activities and monitoring of self-reporting. The regulatory framework has been improved by clarifying expectations through the issuance of S-210 'Maintenance Programs for Nuclear Power Plants'. Inspection activities have been improved by introducing new maintenance inspections into the baseline program. Monitoring is being improved by making better use of self-reported and industry produced maintenance related performance indicators. As with any type of program change, the challenge is to ensure the consistent and optimal application of regulatory activities and resources. This paper is a summary of the CNSC's approach to improving its maintenance oversight strategy. (author)

Automated System Checkout to Support Predictive Maintenance for the Reusable Launch Vehicle

Science.gov (United States)

Patterson-Hine, Ann; Deb, Somnath; Kulkarni, Deepak; Wang, Yao; Lau, Sonie (Technical Monitor)

1998-01-01

The Propulsion Checkout and Control System (PCCS) is a predictive maintenance software system. The real-time checkout procedures and diagnostics are designed to detect components that need maintenance based on their condition, rather than using more conventional approaches such as scheduled or reliability centered maintenance. Predictive maintenance can reduce turn-around time and cost and increase safety as compared to conventional maintenance approaches. Real-time sensor validation, limit checking, statistical anomaly detection, and failure prediction based on simulation models are employed. Multi-signal models, useful for testability analysis during system design, are used during the operational phase to detect and isolate degraded or failed components. The TEAMS-RT real-time diagnostic engine was developed to utilize the multi-signal models by Qualtech Systems, Inc. Capability of predicting the maintenance condition was successfully demonstrated with a variety of data, from simulation to actual operation on the Integrated Propulsion Technology Demonstrator (IPTD) at Marshall Space Flight Center (MSFC). Playback of IPTD valve actuations for feature recognition updates identified an otherwise undetectable Main Propulsion System 12 inch prevalve degradation. The algorithms were loaded into the Propulsion Checkout and Control System for further development and are the first known application of predictive Integrated Vehicle Health Management to an operational cryogenic testbed. The software performed successfully in real-time, meeting the required performance goal of 1 second cycle time.

The safety monitor and RCM workstation as complementary tools in risk based maintenance optimization

International Nuclear Information System (INIS)

Rawson, P.D.

2000-01-01

Reliability Centred Maintenance (RCM) represents a proven technique for rendering maintenance activities safer, more effective, and less expensive, in terms of systems unavailability and resource management. However, it is believed that RCM can be enhanced by the additional consideration of operational plant risk. This paper discusses how two computer-based tools, i.e., the RCM Workstation and the Safety Monitor, can complement each other in helping to create a living preventive maintenance strategy. (author)

Development of maintenance composite priority index for buildings in Palestine: A pilot case study

Science.gov (United States)

Issa, Amjad; Awad, Riyad

2017-11-01

The current building maintenance practices in Palestine are not based on scientific systematic methods. Most of the municipalities use one criterion to define the maintenance priorities, which is the "worst-first" criterion. Therefore, the current practices in defining buildings maintenance plans are not dealing with the known phases that are generally followed, including those in establishing building inventories, building condition survey, detailed visual inspection, identification of the proper maintenance and rehabilitation measures, and setting priorities. Accordingly, the recent preparation of the Operation and Maintenance (O&M) Manual for Palestinian municipalities is an important step to guide them towards preparing and implementing their O&M priority-based plans, considering scare resources. During the course of preparation of the Manual, the proposed procedures were applied at ten pilot municipalities. This study aims to explore the outcome of the implementation of the 2014/2015 O&M buildings maintenance priorities at these municipalities through the development of maintenance composite priority index (PI). The new proposed priority index is a scientific tool that will identify the priority of maintenance buildings through using a systematic procedure instead of first worst one. To achieve this, analyses of the outcome of a questionnaire designed to collect relevant information from these municipalities was conducted. The maintenance priority index for buildings is calculated considering different indicators among them building status (condition), classification and importance of the building, number of beneficiaries (users), safety aspects (severity level in the building), and people complaints. The main component of the PI is the building condition index (BCI) which forms about 40% of the total weight. The physical inspection, which is the main input for calculating the BCI, is conducted on two levels; the primary level, and the secondary level. The

Optimum analysis of pavement maintenance using multi-objective genetic algorithms

Directory of Open Access Journals (Sweden)

Amr A. Elhadidy

2015-04-01

Full Text Available Road network expansion in Egypt is considered as a vital issue for the development of the country. This is done while upgrading current road networks to increase the safety and efficiency. A pavement management system (PMS is a set of tools or methods that assist decision makers in finding optimum strategies for providing and maintaining pavements in a serviceable condition over a given period of time. A multi-objective optimization problem for pavement maintenance and rehabilitation strategies on network level is discussed in this paper. A two-objective optimization model considers minimum action costs and maximum condition for used road network. In the proposed approach, Markov-chain models are used for predicting the performance of road pavement and to calculate the expected decline at different periods of time. A genetic-algorithm-based procedure is developed for solving the multi-objective optimization problem. The model searched for the optimum maintenance actions at adequate time to be implemented on an appropriate pavement. Based on the computing results, the Pareto optimal solutions of the two-objective optimization functions are obtained. From the optimal solutions represented by cost and condition, a decision maker can easily obtain the information of the maintenance and rehabilitation planning with minimum action costs and maximum condition. The developed model has been implemented on a network of roads and showed its ability to derive the optimal solution.

The method for assurance to operational safety of cryogenics equipment through definite maintenance

International Nuclear Information System (INIS)

Anghel, Vasile

2004-01-01

The present paper reports about a method of ensuring operational safety of cryogenics equipment through specific maintenance measures which imply a definite concept of maintainability and operational reliability, methods of maintenance, necessary logistic and necessary personnel. The stages of the concept should succeed in a logical order and must be based on detailed analyses of the process of maintenance. The method starts from the operation conditions of cryogenic equipment in nuclear regime. Thus maintenance policy must be well defined within the boundaries of the nuclear plant through definition of coherent objectives and responsibility delegation for the personnel implied in maintenance activity. This method ensures performance in maintenance and an efficient feedback from equipment analysis. (author)

Maintenance Production Demand and Capacity Analysis of Third Maintenance Battalion

Science.gov (United States)

2017-12-01

Delivery T/E Table of Equipment TFSMS Total Force Structure Management System TFSP Total Force Structure Process TM Technical Manual T/O Table of...exercises each year, both on Okinawa and throughout the Pacific theater. When equipment requires maintenance beyond the organizational -level...demand was analyzed based on customer cycle time (i.e., time that equipment was in Third Maintenance Battalion custody), maintenance cycle time during

A Tailored Ontology Supporting Sensor Implementation for the Maintenance of Industrial Machines

Directory of Open Access Journals (Sweden)

Elaheh Maleki

2017-09-01

Full Text Available The longtime productivity of an industrial machine is improved by condition-based maintenance strategies. To do this, the integration of sensors and other cyber-physical devices is necessary in order to capture and analyze a machine’s condition through its lifespan. Thus, choosing the best sensor is a critical step to ensure the efficiency of the maintenance process. Indeed, considering the variety of sensors, and their features and performance, a formal classification of a sensor’s domain knowledge is crucial. This classification facilitates the search for and reuse of solutions during the design of a new maintenance service. Following a Knowledge Management methodology, the paper proposes and develops a new sensor ontology that structures the domain knowledge, covering both theoretical and experimental sensor attributes. An industrial case study is conducted to validate the proposed ontology and to demonstrate its utility as a guideline to ease the search of suitable sensors. Based on the ontology, the final solution will be implemented in a shared repository connected to legacy CAD (computer-aided design systems. The selection of the best sensor is, firstly, obtained by the matching of application requirements and sensor specifications (that are proposed by this sensor repository. Then, it is refined from the experimentation results. The achieved solution is recorded in the sensor repository for future reuse. As a result, the time and cost of the design process of new condition-based maintenance services is reduced.

A Tailored Ontology Supporting Sensor Implementation for the Maintenance of Industrial Machines.

Science.gov (United States)

Maleki, Elaheh; Belkadi, Farouk; Ritou, Mathieu; Bernard, Alain

2017-09-08

The longtime productivity of an industrial machine is improved by condition-based maintenance strategies. To do this, the integration of sensors and other cyber-physical devices is necessary in order to capture and analyze a machine's condition through its lifespan. Thus, choosing the best sensor is a critical step to ensure the efficiency of the maintenance process. Indeed, considering the variety of sensors, and their features and performance, a formal classification of a sensor's domain knowledge is crucial. This classification facilitates the search for and reuse of solutions during the design of a new maintenance service. Following a Knowledge Management methodology, the paper proposes and develops a new sensor ontology that structures the domain knowledge, covering both theoretical and experimental sensor attributes. An industrial case study is conducted to validate the proposed ontology and to demonstrate its utility as a guideline to ease the search of suitable sensors. Based on the ontology, the final solution will be implemented in a shared repository connected to legacy CAD (computer-aided design) systems. The selection of the best sensor is, firstly, obtained by the matching of application requirements and sensor specifications (that are proposed by this sensor repository). Then, it is refined from the experimentation results. The achieved solution is recorded in the sensor repository for future reuse. As a result, the time and cost of the design process of new condition-based maintenance services is reduced.

On maintenance management of wind and nuclear power plants

International Nuclear Information System (INIS)

Nilsson, Julia

2009-11-01

Electrical production in Sweden today is mainly from nuclear and hydro power. However, there is large increase in renewable energy like wind power and the installed new capacity goals are large. Several electrical production sources are important for the sustainability of the energy system. Maintenance is an approach for keeping a system sustainable. The importance of structured maintenance for reliable electrical production systems triggers the development of qualitative and quantitative maintenance management methods. Examples of these methods are Reliability-Centered Maintenance (RCM) which is a structured qualitative approach that focuses on reliability when planning maintenance, and Reliability Centered Asset Management (RCAM) which is a development of RCM into a quantitative approach with the aim to relate preventive maintenance to total maintenance cost and system reliability. This thesis presents models, as applications of RCAM, based on the methods of Life Cycle Cost (LCC) and mathematical optimization, applied to wind and nuclear power plants. Both deterministic and stochastic approaches have been used and the proposed models are based on the Total Cost model, which summarizes costs for maintenance and production loss, and the Aircraft model, which is an opportunistic maintenance optimization model. Opportunistic maintenance is preventive maintenance performed at opportunities. The wind power applications in this study show on different ways to cover costs of condition monitoring systems (CMS) and further on economic benefits of these when uncertainties of times to failure are included in the model. The nuclear power applications show on that the optimization model is dependent on the discount rate and that a high discount rate gives more motivation for opportunistic replacements. When put into a stochastic framework and compared to other maintenance strategies it is shown that an extended opportunistic maintenance optimization model has a good overall

On risk-based operation and maintenance of offshore wind turbine components

DEFF Research Database (Denmark)

Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

2011-01-01

Operation and maintenance are significant contributors to the cost of energy for offshore wind turbines. Optimal planning could rationally be based on Bayesian pre-posterior decision theory, and all costs through the lifetime of the structures should be included. This paper contains a study...... of a generic case where the costs are evaluated for a single wind turbine with a single component. Costs due to inspections, repairs, and lost production are included in the model. The costs are compared for two distinct maintenance strategies, namely with and without inclusion of periodic imperfect...

A reliability program for emergency diesel generators at nuclear power plants: Maintenance, surveillance, and condition monitoring

International Nuclear Information System (INIS)

Lofgren, E.V.; Henderson, W.; Burghardt, D.; Kripps, L.; Rothleder, B.

1988-12-01

This report is a companion report on NUREG/CR-5078, Volume 1, ''A Reliability Program for Emergency Diesel Generators at Nuclear Power Plants: Program Structure.'' The purpose of this report is to provide technical findings and insights related to: failure evaluation, troubleshooting, maintenance, surveillance, and condition monitoring. Examples and recommendations are provided for each of these areas based on actual emergency diesel generator (EDG) operating experience and the opinions of diesel generator experts. This report expands the more general guidance provided in Volume 1. In addition, a discussion of EDG interactions with other plant systems (e.g., instrument, air, service water, dc power) is provided since experience has shown that these support systems and their operation can adversely affect EDG reliability. Portions of this report have been designed for use by onsite personnel for evaluating operational characteristics of EDGs. 5 refs., 8 figs., 7 tabs

Pavement maintenance procedures with and without milling materials

Directory of Open Access Journals (Sweden)

Rafiqul A. Tarefder

2016-01-01

Full Text Available This study evaluates maintenance treatment followed by different Districts of New Mexico Department of Transportation (NMDOT. In addition, two case studies on the use of old pavement materials, called the “millings”, in maintenance projects are reported. Based on this study, it is observed that none of the Districts have a written procedure for maintenance work. Rather Districts rely on the experience of the maintenance crew for conducting maintenance projects. All Districts prefer to use chip seal for maintenance irrespective of distress conditions of the pavements. Patching and crack sealing are usually done before chip sealing to extend the life of the chip seals. Sand seal, scrub seal, and slurry seal projects are not done by District maintenance crews but by outside contractors. It is also observed that all Districts are interested in using millings in maintenance projects and most have already used millings in at least one maintenance project with some success and failure. Most of the Districts have used coarse fraction of millings in chip seal projects successfully. However, they failed to find a proper way to process the fine fractions of millings. Case Study I shows that fine millings can be used to construct thin overlay when mixed with emulsion in pug mill or hot drums. Case Study II concludes that fine millings can be used as fine/sand seal successfully following the same procedure and using the same equipment as chip seal. Keywords: Millings, Maintenance, Emulsion, Rutting, Pug-mill

GRAPHICAL MODELS OF THE AIRCRAFT MAINTENANCE PROCESS

Directory of Open Access Journals (Sweden)

Stanislav Vladimirovich Daletskiy

2017-01-01

Full Text Available The aircraft maintenance is realized by a rapid sequence of maintenance organizational and technical states, its re- search and analysis are carried out by statistical methods. The maintenance process concludes aircraft technical states con- nected with the objective patterns of technical qualities changes of the aircraft as a maintenance object and organizational states which determine the subjective organization and planning process of aircraft using. The objective maintenance pro- cess is realized in Maintenance and Repair System which does not include maintenance organization and planning and is a set of related elements: aircraft, Maintenance and Repair measures, executors and documentation that sets rules of their interaction for maintaining of the aircraft reliability and readiness for flight. The aircraft organizational and technical states are considered, their characteristics and heuristic estimates of connection in knots and arcs of graphs and of aircraft organi- zational states during regular maintenance and at technical state failure are given. It is shown that in real conditions of air- craft maintenance, planned aircraft technical state control and maintenance control through it, is only defined by Mainte- nance and Repair conditions at a given Maintenance and Repair type and form structures, and correspondingly by setting principles of Maintenance and Repair work types to the execution, due to maintenance, by aircraft and all its units mainte- nance and reconstruction strategies. The realization of planned Maintenance and Repair process determines the one of the constant maintenance component. The proposed graphical models allow to reveal quantitative correlations between graph knots to improve maintenance processes by statistical research methods, what reduces manning, timetable and expenses for providing safe civil aviation aircraft maintenance.

Knowledge-based machine indexing from natural language text: Knowledge base design, development, and maintenance

Science.gov (United States)

Genuardi, Michael T.

1993-01-01

One strategy for machine-aided indexing (MAI) is to provide a concept-level analysis of the textual elements of documents or document abstracts. In such systems, natural-language phrases are analyzed in order to identify and classify concepts related to a particular subject domain. The overall performance of these MAI systems is largely dependent on the quality and comprehensiveness of their knowledge bases. These knowledge bases function to (1) define the relations between a controlled indexing vocabulary and natural language expressions; (2) provide a simple mechanism for disambiguation and the determination of relevancy; and (3) allow the extension of concept-hierarchical structure to all elements of the knowledge file. After a brief description of the NASA Machine-Aided Indexing system, concerns related to the development and maintenance of MAI knowledge bases are discussed. Particular emphasis is given to statistically-based text analysis tools designed to aid the knowledge base developer. One such tool, the Knowledge Base Building (KBB) program, presents the domain expert with a well-filtered list of synonyms and conceptually-related phrases for each thesaurus concept. Another tool, the Knowledge Base Maintenance (KBM) program, functions to identify areas of the knowledge base affected by changes in the conceptual domain (for example, the addition of a new thesaurus term). An alternate use of the KBM as an aid in thesaurus construction is also discussed.

Interval of Routine Maintenance and Maintenance Performance: A Literature Review

Directory of Open Access Journals (Sweden)

Au-Yong Cheong Peng

2016-01-01

Full Text Available In high-rise residential buildings, the quality of facilities management services is significant to the normal operation of the facilities. Unfortunately, lack of concern towards building maintenance, especially preventive maintenance, happens in domestic housing industry in Malaysia. Majority of the maintenance operations of condominiums suffer from lack of planning, lack of proactive maintenance plan, and lack of proper implementation. Thus, this paper reviews the implementation of preventive maintenance strategy, routine maintenance in specific. An extensive review of literature published in 1987 to 2014 is performed for the purpose of this research. The publications are sourced from journal articles, conference proceedings and books. The literature analysis confirms that the routine maintenance of facilities and building services is vital and it can be influential towards the maintenance performance. Subsequently, a theoretical framework is developed, which shows the relationship between routine maintenance of building facilities & services and maintenance performance. The building facilities & services are divided into two categories. They are essential facilities & services that ensure the safety, health, habitability, and operability of buildings; while value-added facilities & services deal with property value, return on investment, and quality living of buildings. Based on the findings, a future research is proposed, which aims to identify the appropriate routine of maintenance for the facilities and services in high-rise residential buildings to improve the maintenance performance.

Some problems of maintenance regulation at Ukrainian nuclear power plants

International Nuclear Information System (INIS)

Koltakov, V.

1997-01-01

Among all the possible problems arising in a connection with provision of NPP power units safe operation, the maintenance and repair at the Ukrainian NPPs possess an important place. System of maintenance and repair at the Ukrainian NPPs is presently still traditional one, based on the former USSR' document ''Rules of the NPPs Equipment Maintenance and Repair Arrangement'' (RD.53.025.002-088). For to provide technical systems reliability and safety in an accordance with ''General Provisions on NPP Safety'' (OPB-82) (presently OPB-95 is in underway in Ukraine) nuclear operators are implementing their maintenance and repair. These procedures are obligatory conditions for NPP operation during all the life term. To implement an equipment maintenance and repair there are appropriate divisions in NPP structure envisaged such as departments, laboratories, sections, shops, etc. composing an NPP maintenance and repair service. There are also another specific enterprises engaged in such activities. (author). 2 tabs, 4 diagrams

Development of diagnosis and maintenance support system for nuclear power plants with flexible inference function and knowledge base edition support function

International Nuclear Information System (INIS)

Fujii, Makoto; Seki, Eiji; Tai, Ichiro; Morioka, Toshihiko

1988-01-01

For the reliable and efficient diagnosis and inspection work of the nuclear power plant equipments, 'Diagnosis and Maintenance Support System' has been developed. This system has functions to assist operators or engineers to observe and evaluate equipment conditions based on the experts' knowledge. These functions are carried out through dialogue between the system and users. This system has two subsystems: diagnosis subsystem and knowledge base edition support subsystem. To achieve the functions of diagnosis subsystem, a new method of knowledge processing for equipment diagnosis is adopted. This method is based on the concept of 'Cause Generation and Checking'. Knowledge for diagnosis is represented with modularized production rules. And each rule module consists of four different type rules with hierarchical structure. With this approach, the system is equipped with sufficient performance not only in diagnosis function but also in flexible man-machine interface. Knowledge base edition support subsystem (Graphical Rule Editor) is provided for this system. This editor has functions to display and edit the contents of knowledge base with tree structures through the graphic display. With these functions, the efficiency of constructing expert system is highly improved. By applying this system to the maintenance support of neutron monitoring system, it is proved that this system has satisfactory performance as a diagnosis and maintenance support system. (author)

Paranal maintenance and CMMS experience

Science.gov (United States)

Montano, Nelson

2004-10-01

During the last four years of operations, low technical downtime has been one of the relevant records of the Paranal Observatory. From the beginning of the Very Large Telescope (VLT) project, European Southern Observatory (ESO) has considered the implementation of a proper maintenance strategy a fundamental point in order to ensure low technical down time and preserve the Observatory's assets. The implementation of the maintenance strategy was based on the following aspects: - Strong maintenance sense during the design stage. Line Replacement Unit (LRU) concept, standardization and modularity of the Observatory equipment - Creation of a dedicated team for Maintenance - The implementation of a Computerized Maintenance Management System After four operational years, the result of these aspects has exceeded the expectations; the Observatory has been operating with high availability under a sustainable strategy. The strengths of the maintenance strategy have been based on modern maintenance concepts applied by regular production companies, where any minute of down time involves high cost. The operation of the actual Paranal Maintenance System is based mainly on proactive activities, such as regular inspections, preventive maintenance (PM) and predictive maintenance (PdM) plans. Nevertheless, it has been necessary to implement a strong plan for corrective maintenance (CM). The Spare Parts Strategy has also been an important point linked to the Maintenance Strategy and CMMS implementation. At present, almost 4,000 items related to the Observatory spare parts are loaded into the CMMS database. Currently, we are studying the implementation of a Reliability Centered Maintenance (RCM) project in one of our critical systems The following document presents the actual status of the Paranal Maintenance Strategy and which have been the motivations to implement the established strategy.

Reducing maintenance costs

International Nuclear Information System (INIS)

Zaiss, W.; Reuschle, K.; Baier, B.

2002-01-01

The increasingly more expensive maintenance measures, cuts in the cost budget, and the loss of know-how on the part of vendors all require a change of policy with respect to maintenance concepts of the part of operators. This also applies to the existing valve concepts, the drives included. Under these aspects, the current drive, which is self-actuated and actuated by outside media, for a parallel-plate valve of a nomial width of 700 was reconsidered. The effort served to reduce maintenance costs and, at the same time, simplify the drive concept as well as cut back on the number of in-service inspections. Moreover, the number of active components were to be minimized and installation conditions in the plant were to be improved. When the boundary conditions to be observed with respect to process technology had been laid down, the competent technical department developed a concept of modification of the drive. A major constituent part was the demonstration of the functioning capability of the new drive under accident conditions. It was achieved mainly by an analytical approach. In the resultant drive concept, the same control valves are employed to actuate a driving cylinder by means of self-actuation or by an outside medium as a function of pressure. (orig.) [de

Inspection, evaluation and maintenance guidelines for reactor vessel internals in JAPAN

International Nuclear Information System (INIS)

Sakashita, Akihiro; Goto, Tomoya; Hirano, Shinro; Dozaki, Koji

2010-01-01

Inspection and Evaluation Guidelines for reactor internals has been taken into the Rules on Fitness-for–Service for Nuclear Power Plants of The Japan Society of Mechanical Engineers. It is a base of the maintenance plan of each Nuclear Power Plant. A plant maintenance methodology will have more importance to maintain the plant safety and stable plant operation. This paper introduces the systematization of the maintenance such as repair, replacement, preventive maintenance in these guidelines. Maintenance methodologies are classified follows. Repair: methodology to reinforce degraded parts by some methods or prevent progress of degradation of without replacement of the existing structure when the degradation of structure is actualized. Replacement: methodology to replace the existing structure with new one when the degradation of structure is actualized. Preventive maintenance : methodology to mitigate the damaged condition. When the maintenance methodologies are implemented in the actual plant, we have to consider the feedback of the inspection program and plant life management. (author)

Feature-based and object-based attention orientation during short-term memory maintenance.

Science.gov (United States)

Ku, Yixuan

2015-12-01

Top-down attention biases the short-term memory (STM) processing at multiple stages. Orienting attention during the maintenance period of STM by a retrospective cue (retro-cue) strengthens the representation of the cued item and improves the subsequent STM performance. In a recent article, Backer et al. (Backer KC, Binns MA, Alain C. J Neurosci 35: 1307-1318, 2015) extended these findings from the visual to the auditory domain and combined electroencephalography to dissociate neural mechanisms underlying feature-based and object-based attention orientation. Both event-related potentials and neural oscillations explained the behavioral benefits of retro-cues and favored the theory that feature-based and object-based attention orientation were independent. Copyright © 2015 the American Physiological Society.

Development of system decision support tools for behavioral trends monitoring of machinery maintenance in a competitive environment

Science.gov (United States)

Adeyeri, Michael Kanisuru; Mpofu, Khumbulani

2017-06-01

The article is centred on software system development for manufacturing company that produces polyethylene bags using mostly conventional machines in a competitive world where each business enterprise desires to stand tall. This is meant to assist in gaining market shares, taking maintenance and production decisions by the dynamism and flexibilities embedded in the package as customers' demand varies under the duress of meeting the set goals. The production and machine condition monitoring software (PMCMS) is programmed in C# and designed in such a way to support hardware integration, real-time machine conditions monitoring, which is based on condition maintenance approach, maintenance decision suggestions and suitable production strategies as the demand for products keeps changing in a highly competitive environment. PMCMS works with an embedded device which feeds it with data from the various machines being monitored at the workstation, and the data are read at the base station through transmission via a wireless transceiver and stored in a database. A case study was used in the implementation of the developed system, and the results show that it can monitor the machine's health condition effectively by displaying machines' health status, gives repair suggestions to probable faults, decides strategy for both production methods and maintenance, and, thus, can enhance maintenance performance obviously.

Planning of operation & maintenance using risk and reliability based methods

DEFF Research Database (Denmark)

Florian, Mihai; Sørensen, John Dalsgaard

2015-01-01

Operation and maintenance (OM) of offshore wind turbines contributes with a substantial part of the total levelized cost of energy (LCOE). The objective of this paper is to present an application of risk- and reliability-based methods for planning of OM. The theoretical basis is presented...

Development of plant maintenance systems

International Nuclear Information System (INIS)

Tomita, Jinji; Ike, Masae; Nakayama, Kenji; Kato, Hisatomo

1989-01-01

Toshiba is making active efforts for the continuing improvement of reliability and maintainability of operating nuclear power plants. As a part of these efforts, the company has developed new maintenance administration systems, diagnostic monitoring facilities for plant equipments, computer-aided expert systems, and remote-controlled machines for maintenance work. The maintenance administration systems provide efficient work plans and data acquisition capabilities for the management of personnel and equipments involved in nuclear power plant maintenance. The plant diagnostic facilities monitor and diagnose plant conditions for preventive maintenance, as well as enabling rapid countermeasures to be carried out should they be required. Expert systems utilizing artificial intelligence (AI) technology are also employed. The newly developed remote-controlled machines are useful tools for the maintenance inspection of equipment which can not be easily accessed. (author)

Conversion of a mainframe simulation for maintenance performance to a PC environment

International Nuclear Information System (INIS)

Gertman, D.I.

1991-01-01

A computer-based simulation capable of generating human error probabilities (HEPs) for maintenance activities is presented. The HEPs are suitable for use in probabilistic risk assessments (PRAs) and are an important source of information for data management systems such as NUCLARR- the Nuclear Computerized Library for Assessing Reactor Reliability. (1) The basic computer model MAPPS--the maintenance personnel performance simulation has been developed and validated by the US NRC in order to improve maintenance practices and procedures at nuclear power plants. This model validated previously, has now been implemented and improved, in a PC environment, and renamed MicroMAPPS. The model is stochastically based, able to simulate the performance of 2 to 15 person crews for a variety of maintenance conditions. These conditions include aspects of crew actions as potentially influenced by the task, the environment, or characteristics of the personnel involved. The nature of the software code makes it particularly appropriate for determining changes in HEP rates due to fluctuations in important task, environment,. or personnel parameters. The presentation presents a brief review of the mainframe version of the code and presents a summarization of the enhancements which dramatically change the nature of the human computer interaction

Cernavoda NPP risk - Based test and maintenance planning - Methodology development

International Nuclear Information System (INIS)

Georgescu, G.; Popa, P.; Petrescu, A.; Naum, M.; Gutu, M.

1997-01-01

The Cernavoda Power Plant starts the commercial operation in November 1996. During operation of the nuclear power plant, several mandatory tests and maintenance are performed on stand-by safety system components to ensure their availability in case of accident. The basic purpose of such activities is the early detection of any failure and degradation, and timely correction of deteriorations. Because of the large number of such activities, emphasis on plant safety and allocation of resources becomes difficult. The probabilistic model and methodology can be effectively used to obtain the risk significance of these activities so that the resources are directed to the most important areas. The proposed Research Contract activity is strongly connected with other safety related areas under development. Since, the Cernavoda Probabilistic Safety Evaluation Level 1 PSA Study (CPSE) was performed and now the study is revised taking into account the as-built information, it is recommended to implement into the model the necessary modeling features to support further PSA application, especially related to Test and Maintenance optimization. Methods need to be developed in order to apply the PSA model including risk information together with other needed information for Test and Maintenance optimization. Also, in parallel with the CPSE study updating, the software interface for the PSA model is under development (Risk Monitor Software class), methods and models needing to be developed for the purpose of using it for qualified monitoring of Test and Maintenance Strategy efficiency. Similar, the Data Collection System need to be appropriate for the purpose of an ongoing implementation of a risk - based Test and Maintenance Strategy. (author). 4 refs, 1 fig

Knowledge maintenance in myCBR

OpenAIRE

Aul, Vani; Sauer, Christian; Roth-Berghofer, Thomas

2014-01-01

CBR systems, being knowledge based systems, process knowledge. Due to changes in the environment a CBR system’s knowledge model can become outdated, thus creating a need for constant maintenance of said knowledge model. In this paper, we describe an implementation of (semi-)automatic knowledge maintenance of two of the four knowledge containers of CBR systems, specifically case base maintenance and maintenance of similarity measures within the CBR system development SDK myCBR. We describe our...

An Aircraft Lifecycle Approach for the Cost-Benefit Analysis of Prognostics and Condition-Based Maintenance-Based on Discrete-Event Simulation

Science.gov (United States)

2014-10-02

MPD. This manufacturer documentation contains maintenance tasks with specification of intervals and required man-hours that are to be carried out...failures, without consideration of false alarms and missed failures (see also section 4.1.3). The task redundancy rate is the percentage of preventive...Prognostics and Health Management ROI return on investment RUL remaining useful life TCG task code group SB Service Bulletin XML Extensible Markup

Assessment of a maintenance model for a multi-deteriorating mode system

International Nuclear Information System (INIS)

Ponchet, Amelie; Fouladirad, Mitra; Grall, Antoine

2010-01-01

This paper deals with maintenance policies for stochastically deteriorating systems which are subject to sudden changes in their degradation processes. The main aim is to assess the interest of using change mode monitoring information from a maintenance decision making point of view. Two condition-based maintenance policies are considered and compared, each of them adapted to a specific level of available information, with or without change mode monitoring. Numerical examples show that the time distribution of the change of deterioration rate and the difference between the two possible deterioration rates strongly influence the choice of the best decision rule structure.

Assessment of a maintenance model for a multi-deteriorating mode system

Energy Technology Data Exchange (ETDEWEB)

Ponchet, Amelie, E-mail: amelie.ponchet@utt.f [Institut Charles Delaunay, Universite de technologie de Troyes, UMR CNRS 6279 STMR, 12 rue Marie Curie, 10010 Troyes (France); Fouladirad, Mitra [Institut Charles Delaunay, Universite de technologie de Troyes, UMR CNRS 6279 STMR, 12 rue Marie Curie, 10010 Troyes (France); Grall, Antoine, E-mail: antoine.grall@utt.f [Institut Charles Delaunay, Universite de technologie de Troyes, UMR CNRS 6279 STMR, 12 rue Marie Curie, 10010 Troyes (France)

2010-11-15

This paper deals with maintenance policies for stochastically deteriorating systems which are subject to sudden changes in their degradation processes. The main aim is to assess the interest of using change mode monitoring information from a maintenance decision making point of view. Two condition-based maintenance policies are considered and compared, each of them adapted to a specific level of available information, with or without change mode monitoring. Numerical examples show that the time distribution of the change of deterioration rate and the difference between the two possible deterioration rates strongly influence the choice of the best decision rule structure.

Computer-Based Simulations for Maintenance Training: Current ARI Research. Technical Report 544.

Science.gov (United States)

Knerr, Bruce W.; And Others

Three research efforts that used computer-based simulations for maintenance training were in progress when this report was written: Game-Based Learning, which investigated the use of computer-based games to train electronics diagnostic skills; Human Performance in Fault Diagnosis Tasks, which evaluated the use of context-free tasks to train…

Robustness evaluation of cutting tool maintenance planning for soft ground tunneling projects

Directory of Open Access Journals (Sweden)

Alena Conrads

2018-03-01

Full Text Available Tunnel boring machines require extensive maintenance and inspection effort to provide a high availability. The cutting tools of the cutting wheel must be changed timely upon reaching a critical condition. While one possible maintenance strategy is to change tools only when it is absolutely necessary, tools can also be changed preventively to avoid further damages. Such different maintenance strategies influence the maintenance duration and the overall project performance. However, determine downtime related to a particular maintenance strategy is still a challenging task. This paper shows an analysis of the robustness to achieve the planned project performance of a maintenance strategy considering uncertainties of wear behavior of the cutting tools. A simulation based analysis is presented, implementing an empirical wear prediction model. Different strategies of maintenance planning are compared by performing a parameter variation study including Monte-Carlo simulations. The maintenance costs are calculated and evaluated with respect to their robustness. Finally, an improved and robust maintenance strategy has been determined. Keywords: Mechanized tunneling, Maintenance, Wear of cutting tools, Process simulation, Robustness, Uncertainty modeling

Research on gesture recognition of augmented reality maintenance guiding system based on improved SVM

Science.gov (United States)

Zhao, Shouwei; Zhang, Yong; Zhou, Bin; Ma, Dongxi

2014-09-01

Interaction is one of the key techniques of augmented reality (AR) maintenance guiding system. Because of the complexity of the maintenance guiding system's image background and the high dimensionality of gesture characteristics, the whole process of gesture recognition can be divided into three stages which are gesture segmentation, gesture characteristic feature modeling and trick recognition. In segmentation stage, for solving the misrecognition of skin-like region, a segmentation algorithm combing background mode and skin color to preclude some skin-like regions is adopted. In gesture characteristic feature modeling of image attributes stage, plenty of characteristic features are analyzed and acquired, such as structure characteristics, Hu invariant moments features and Fourier descriptor. In trick recognition stage, a classifier based on Support Vector Machine (SVM) is introduced into the augmented reality maintenance guiding process. SVM is a novel learning method based on statistical learning theory, processing academic foundation and excellent learning ability, having a lot of issues in machine learning area and special advantages in dealing with small samples, non-linear pattern recognition at high dimension. The gesture recognition of augmented reality maintenance guiding system is realized by SVM after the granulation of all the characteristic features. The experimental results of the simulation of number gesture recognition and its application in augmented reality maintenance guiding system show that the real-time performance and robustness of gesture recognition of AR maintenance guiding system can be greatly enhanced by improved SVM.

Decreasing inventory of a cement factory roller mill parts using reliability centered maintenance method

Science.gov (United States)

Witantyo; Rindiyah, Anita

2018-03-01

According to data from maintenance planning and control, it was obtained that highest inventory value is non-routine components. Maintenance components are components which procured based on maintenance activities. The problem happens because there is no synchronization between maintenance activities and the components required. Reliability Centered Maintenance method is used to overcome the problem by reevaluating maintenance activities required components. The case chosen is roller mill system because it has the highest unscheduled downtime record. Components required for each maintenance activities will be determined by its failure distribution, so the number of components needed could be predicted. Moreover, those components will be reclassified from routine component to be non-routine component, so the procurement could be carried out regularly. Based on the conducted analysis, failure happens in almost every maintenance task are classified to become scheduled on condition task, scheduled discard task, schedule restoration task and no schedule maintenance. From 87 used components for maintenance activities are evaluated and there 19 components that experience reclassification from non-routine components to routine components. Then the reliability and need of those components were calculated for one-year operation period. Based on this invention, it is suggested to change all of the components in overhaul activity to increase the reliability of roller mill system. Besides, the inventory system should follow maintenance schedule and the number of required components in maintenance activity so the value of procurement will be decreased and the reliability system will increase.

Periodic imperfect preventive maintenance with two categories of competing failure modes

Energy Technology Data Exchange (ETDEWEB)

Zequeira, R.I. [ISTIT FRE CNRS 2732-Equipe LM2S, Universite de Technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes (France)]. E-mail: romulo.zequeira@utt.fr; Berenguer, C. [ISTIT FRE CNRS 2732-Equipe LM2S, Universite de Technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes (France)]. E-mail: christophe.berenguer@utt.fr

2006-04-15

A maintenance policy is studied for a system with two types of failure modes: maintainable and non-maintainable. The quality of maintenance actions is modelled by its effect on the system failure rate. Preventive maintenance actions restore the system to a condition between as good as new and as bad as immediately before the maintenance action. The model presented permits to study the equipment condition improvement (improvement factor) as a function of the time of the preventive maintenance action. The determination of the maintenance policy, which minimizes the cost rate for an infinite time span, is examined. Conditions are given under which a unique optimal policy exists.

Periodic imperfect preventive maintenance with two categories of competing failure modes

International Nuclear Information System (INIS)

Zequeira, R.I.; Berenguer, C.

2006-01-01

A maintenance policy is studied for a system with two types of failure modes: maintainable and non-maintainable. The quality of maintenance actions is modelled by its effect on the system failure rate. Preventive maintenance actions restore the system to a condition between as good as new and as bad as immediately before the maintenance action. The model presented permits to study the equipment condition improvement (improvement factor) as a function of the time of the preventive maintenance action. The determination of the maintenance policy, which minimizes the cost rate for an infinite time span, is examined. Conditions are given under which a unique optimal policy exists

Routine maintenance: safety term based work selection; Selecao de trabalho baseado no prazo seguro

Energy Technology Data Exchange (ETDEWEB)

Camargo, Albair de; Filho, Antnio S.; Brendler, Fabiano E.; Adamatti, Gilberto A.; Naruto, Itiro; Araujo, Luiz C.F.; Puerari, Roberto [PETROBRAS, Rio de Janeiro, RJ (Brazil)

2004-07-01

This work has objective to present the experience of improvement of routine maintenance system in some refineries of the PETROBRAS system, with the purpose to increase the efficiency in the Industrial Maintenance Management (cost), Utilization and HSE (Health, Safety and Environment), key of success of a petroleum company. The new system is based on the implantation of the culture of work selection in the safe period, through elaboration of new maintenance procedure, with emphasis in decisions shared between Operation and Maintenance Team, resulting in reduction of emergencies, making possible contract of services of maintenance for packages and improved allocation of resources. This work treat about improvement of the system in use, in view of that it has already taken in consideration the consequence of fail in the maintenance with participation of the operators. Besides of these challenge, this modification was made without causing riots in the process of implantation of SAP. As main result, financial profits had got better of resources with increase of safety, considering that they are analyzed in a way it that systematized potential risks. (author)

The radiation protection and its maintenance

International Nuclear Information System (INIS)

Brachet, Y.; Mauclert, J.L.

2003-01-01

This presentation exposes the different phases of the management of an operation taking into account the dosimetry; Each phase is important; the methodology and the analysis are important. The solutions have to be pragmatic and they depend on the context. Relative to the maintenance and dismantling operations for the oldest of nuclear facilities the existence of a data base is necessary to improve the working conditions of the operators. (N.C.)

Comparison of the effects of two anesthesia maintenance methods by remifentanil or halothane on endoscopic sinus surgery condition

Directory of Open Access Journals (Sweden)

Seyed mojtaba Karimi

2008-07-01

Full Text Available Introduction: Endoscopic surgery is a new standard method of treatment for chronic sinusitis. During this operation even small amount of bleeding may reduce the visual field of surgeon significantly and make the procedure troublesome. In this study we have compared the operative condition between patients who receive either remifentanil or halothane for general anesthesia. Materials and Methods: Endoscopic sinus surgery was performed in 60 patents. Pre- medication was done by fentanil and midazolam and induction was done by propofol and atracurium. Halothane or remifentanil was used in two groups of patients respectively for anesthesia maintenance. Monitoring was performed during anesthesia. Bleeding volume was measured and operation field condition was assessed by the surgeon. Results: Personal characteristics such as age and sex were the same in both groups. Intra- operative systolic blood pressures was significantly lower in remifentanil group but diastolic and mean blood pressure and heart rate didn’t change after induction and during maintenance in both groups. Recovery time in remifentanil group was also significantly shorter than halothane group. Finally bleeding volume was lower and operation field condition was better significantly in remifentanil group. Conclusion: Remifentanil is a good choice to maintain an ideal anesthesia for endoscopic sinus surgery.    

A reliability-based preventive maintenance methodology for the projection spot welding machine

Directory of Open Access Journals (Sweden)

Fayzimatov Ulugbek

2018-06-01

Full Text Available An effective operations of a projection spot welding (PSW machine is closely related to the effec-tiveness of the maintenance. Timely maintenance can prevent failures and improve reliability and maintainability of the machine. Therefore, establishing the maintenance frequency for the welding machine is one of the most important tasks for plant engineers. In this regard, reliability analysis of the welding machine can be used to establish preventive maintenance intervals (PMI and to identify the critical parts of the system. In this reliability and maintainability study, analysis of the PSW machine was carried out. The failure and repair data for analysis were obtained from automobile manufacturing company located in Uzbekistan. The machine was divided into three main sub-systems: electrical, pneumatic and hydraulic. Different distributions functions for all sub-systems was tested and their parameters tabulated. Based on estimated parameters of the analyzed distribu-tions, PMI for the PSW machines sub-systems at different reliability levels was calculated. Finally, preventive measures for enhancing the reliability of the PSW machine sub-systems are suggested.

Are air-conditioning maintenance personnel at increased risk of Legionellosis?

Science.gov (United States)

Goldman, W D; Marr, J S

1980-07-01

We surveyed by use of medical questionnaires and blood tests 21 maintenance workers involved with cleaning and servicing cooling towers and evaporative condensers at a large company to determine the frequency of pneumonia and antibody levels against Legionella pneumophila serogroup 1. The 21 high-risk workers were compared with 27 low-risk workers, persons who were not directly involved in service or maintenance for the company. The overall prevalence of titers greater than or equal to 128 for the 21 high-risk workers was 19.0% compared with 22.2% for the low-risk group. There were no significant differences in the history of pneumonia between these groups. Possible explanations for these findings are discussed.

Road Maintenance and Rehabilitation Program Using Functional and Structural Assessment

Science.gov (United States)

Setianingsih, A. I.; Sangaji, S.; Setyawan, A.

2017-02-01

Road sector development policy in Bangka Belitung emphasis on equitable development, which is opening up new areas for industrial development zones of potential marine and coastal tourism, so that having an impact on the budget priority to build a new road. This led to a minimal budget provided for the maintenance of the existing road. This study aimed to evaluate the condition of the pavement both functionally and structurally, the growth of traffic density and the availability of existing road maintenance costs. Then, to analyze the influence of existing road conditions, traffic density and road maintenance costs to the type of road maintenance management. The results are compared with the results of the existing maintenance conducted by the Public Works Department of Bangka Belitung province. Evaluation of pavement conditions consists of visual assessment of pavement condition using IRI, pavement condition assessment functionally with deflection method using test data tool Benkelman Beam (BB) and the actual traffic load. IRI value, deflections and traffic growth gained from years 2011-2015 subsequently created regression models to obtain the relationship and the correlation coefficient. The analysis showed that using the same relative magnitude of the budget from 2011 to 2015, giving priority to the maintenance of the road with good conditions capable of providing the road with a steady state of 100%. Recommendations can be given that maintain the road with good conditions reflecting that preservation provide maximum results with the more efficient maintenance cost.

Maintenance Planning for Historic Buildings

Directory of Open Access Journals (Sweden)

Diana Plian

2008-01-01

Full Text Available The key to good maintenance of historic buildings is a long-range maintenance plan. Long-range planning recognizes a responsibility to the future to prolong the useful life of a building by preserving it in its present condition and preventing or slowing deterioration and damage from natural or other causes.

Lean Maintenance Applied to Improve Maintenance Efficiency in Thermoelectric Power Plants

Directory of Open Access Journals (Sweden)

Orlando Duran

2017-10-01

Full Text Available Thermoelectric power plants consist of a set of critical equipment that require high levels of availability and reliability. Due to this, maintenance of these physical assets is gaining momentum in industry. Maintenance is considered as an activity that contributes to improving the availability, efficiency and productivity of each piece of equipment. Several techniques have been used to achieve greater efficiencies in maintenance, among which we can find the lean maintenance philosophy. Despite the wide diffusion of lean maintenance, there is no structured method that supports the prescription of lean tools applied to the maintenance function. This paper presents the experience gathered in two lean maintenance projects in thermoelectric power plants. The application of lean techniques was based on using a previously developed multicriterial decision making process that uses the Fuzzy Analytic Hierarchy Process (AHP methodology to carry out a diagnosis and prescription tasks. That methodology allowed the prescription of the appropriated lean techniques to resolve the main deficiencies in maintenance function. The results of applying such lean tools show that important results can be obtained, making the maintenance function in thermoelectric power plants more efficient and lean.

MOVES: A knowledge-based system for maintenance planning for motor-operated valves

International Nuclear Information System (INIS)

Winter, M.

1987-01-01

Over the past several years, knowledge-based expert systems have emerged as an important part of the general research area known as artificial intelligence. This paper describes a cooperative effort between faculty members at Iowa State University and engineers at the Duane Arnold Energy Center [a 545-MW(electric) boiling water reactor operated by Iowa Electric Light and Power Company] to explore the development of an advisory system for valve maintenance planning. This knowledge-based program, known as Motor-Operated Valves Expert System (MOVES), has a data base that currently includes safety-related motor-operated valves (∼117 valves). Valve maintenance was selected as the subject for the expert system because of the importance of valves in nuclear plant and their impact of plant availability. MOVES is being developed using the microcomputer-(IBM compatible) based expert system tool INSIGHT2+. The authors have found that the project benefits both the university and the utility

Condition-Based Conveyor Belt Replacement Strategy in Lignite Mines with Random Belt Deterioration

Science.gov (United States)

Blazej, Ryszard; Jurdziak, Leszek

2017-12-01

In Polish lignite surface mines, condition-based belt replacement strategies are applied in order to assure profitable refurbishment of worn out belts performed by external firms specializing in belt maintenance. In two of three lignite mines, staff asses belt condition subjectively during visual inspections. Only one mine applies specialized diagnostic device (HRDS) allowing objective magnetic evaluation of belt core condition in order to choose the most profitable moment for the dismantling of worn out belt segments from conveyors and sending them to the maintenance firm which provides their refurbishment. This article describes the advantages of a new diagnostic device called DiagBelt. It was developed at the Faculty of Geoengineering, Mining and Geology, Wroclaw University of Science and Technology. Economic gains from its application are calculated for the lignite mine and for the belt maintenance firm, taking into account random life (durability) of new and reconditioned belts (after the 1st and the 2nd refurbishment). Recursive calculations for following years allow the estimation of the length and costs of replaced, reconditioned and purchased belts on an annual basis, while the use of the Monte Carlo method allows the estimation of their variability caused by random deterioration of belts. Savings are obtained due to better selection of moments (times) for the replacement of belt segments and die to the possibility to qualify worn out belts for refurbishment without the need to remove their covers. In effect, increased belt durability and lowered share of waste belts (which were not qualified for reconditioning) create savings which can quickly cover expenditures on new diagnostic tools and regular belt inspections in the mine.

A probabilistic maintenance model for diesel engines

Science.gov (United States)

Pathirana, Shan; Abeygunawardane, Saranga Kumudu

2018-02-01

In this paper, a probabilistic maintenance model is developed for inspection based preventive maintenance of diesel engines based on the practical model concepts discussed in the literature. Developed model is solved using real data obtained from inspection and maintenance histories of diesel engines and experts' views. Reliability indices and costs were calculated for the present maintenance policy of diesel engines. A sensitivity analysis is conducted to observe the effect of inspection based preventive maintenance on the life cycle cost of diesel engines.

ECONOMIC EFFICIENCY OF VARIOUS QUEEN BEES MAINTENANCE SYSTEMS

Directory of Open Access Journals (Sweden)

A POPESCU

2003-10-01

Full Text Available The modern queens maintenance systems are based on the use of artificial insemination, queens’ maintenance in the so called „queens bank” , in this way assuring an increased economic efficiency in beekeeping. This study aimed to compare the economic efficiency of the implementation of A.I. to various queen bees maintenance systems. Three alternatives have been taken into account: V1-a queen bee in a cage together with her bees, V2- a queen bank system and V3 – a queen bee in a nucleus. For each queen bee maintenance alternative have been evaluated the most important indicators such as: expenses, incomes, profit, number of marketable inseminated and selected queen bees, honey production, cost/queen, revenue/queen, profit/queen, profit rate. The most effective alternative was the queen bank system assuring 2,400 marketable queen bees and 20 kg honey delivered yearly, USD 12,442 incomes, USD 3,400 expenses, USD 9,042 profit, that is USD 3.77/queen bee and 265.72 % profit rate under the condition as A.I. costs are just USD 1,058, representing 31.1 % of total queen bees maintenance costs.

On Different Maintenance Strategies for Casted Components of Offshore Wind Turbines

DEFF Research Database (Denmark)

Ambühl, Simon; Sørensen, John Dalsgaard

. This maintenance tool uses Crude Monte Carlo Simulations to estimate the expected maintenance costs. Corrective and preventive maintenance strategies with a constant inspection interval or a condition monitoring system are considered. Furthermore, transportation from shore to the wind turbines by boat...... and transportation strategy. The case study shows that the maintenance expenses of casted components correspond to roughly 5% of the overall expected maintenance costs when using a corrective maintenance strategy. This amount can be decreased to roughly 2% when using a condition monitoring system and following...

Rock mechanical conditions at the Aespoe HRL. A study of the correlation between geology, tunnel maintenance and tunnel shape

International Nuclear Information System (INIS)

Andersson, Christer; Soederhaell, Joergen

2001-12-01

Maintenance records including scaling, shotcreting and bolting have been kept since the excavation start of Aespoe HRL 1990 together with records of groundwater flow and all other activities taking place in the tunnels. When the facility was constructed one objective was to limit the rock support as much as possible. The reason for this was that it should be possible to go back and easily study the exposed rock surface. Support during the operational phase has only been carried out where and when necessary. This type of maintenance and its location is documented in the digital database each time. The maintenance records have been compiled and areas requiring more maintenance than average noted. An interview has also been held with one of the miners conducting scaling and bolting in the tunnel. His experiences together with the study of the database maintenance records led to the selection of certain areas in the tunnel to be studied by numerical modelling. The probable reason for the need of additional maintenance in all areas, not only these numerically modelled, has been investigated. Almost all maintenance in the main tunnel both during construction and the operational phase has been located in the widened curves of the access tunnel. The maintenance is also located in areas containing veins or intrusions of Smaaland granite or fine-grained granite. These areas are often located in fracture zones of different sizes or show an increasing fracture frequency. The areas numerically modelled indicate stress concentrations or unloaded stress conditions. The stress concentrations are created by the geometry of the niches and side-tunnels in relation to the in situ stress field. The angle between the tunnel and the major principal stress has an impact on the need for maintenance. The areas with the largest angles towards the principal stress direction need more maintenance than the areas almost parallel to the major principal stress direction. The maintenance work in

Integrated vibration-based maintenance: an approach for continuous reduction in LCC. A case study

Energy Technology Data Exchange (ETDEWEB)

Najjar, B [ER Konsult Utveckling AB, Vaexjoe (Sweden)

1999-12-31

The biggest thread in achieving and maintaining high equipment effectiveness can be stated as: whether the improved manufacturing processes capable of producing quality products at a competitive cost. The effect of a new vibration-based maintenance concept, called Total Quality Maintenance (TQMain), is introduced. It aims to make intensive use of the real-time data acquisition and analysis to detect causes behind product quality deviation and failures in machinery, and following defect development at an early stage to increase machine mean effective life and improve company`s economics. The effect of TQMain on LCC of machinery and company`s economics is discussed. A case study to reveal savings in maintenance cost when a vibration-based policy involved, is presented. Using TQMain, company`s economics can be improved effectively through continuous improvement of the technical and economic effectiveness of production processes. (orig.) 14 refs.

Integrated vibration-based maintenance: an approach for continuous reduction in LCC. A case study

Energy Technology Data Exchange (ETDEWEB)

Najjar, B. [ER Konsult Utveckling AB, Vaexjoe (Sweden)

1998-12-31

The biggest thread in achieving and maintaining high equipment effectiveness can be stated as: whether the improved manufacturing processes capable of producing quality products at a competitive cost. The effect of a new vibration-based maintenance concept, called Total Quality Maintenance (TQMain), is introduced. It aims to make intensive use of the real-time data acquisition and analysis to detect causes behind product quality deviation and failures in machinery, and following defect development at an early stage to increase machine mean effective life and improve company`s economics. The effect of TQMain on LCC of machinery and company`s economics is discussed. A case study to reveal savings in maintenance cost when a vibration-based policy involved, is presented. Using TQMain, company`s economics can be improved effectively through continuous improvement of the technical and economic effectiveness of production processes. (orig.) 14 refs.

Systematic maintenance analysis with decision support method and tool for optimizing maintenance programme

International Nuclear Information System (INIS)

Laakso, K.; Simola, K.; Dorrepaal, J.; Skogberg, P.

1999-01-01

This report describes an approach to evaluate the effectiveness of test and maintenance programs of technical systems used during several years. The method combines an analysis of the historical data on faults and repairs with an analysis of the history of periodic testing and preventive maintenance action programs. The application of the maintenance analysis from the methodological point of view in the reliability centered maintenance (RCM) project for Barsebaeck nuclear power plant is described. In order to limit the analysis resources, a method for ranking of objects for maintenance analysis is needed. Preliminary suggestions for changes in maintenance action programs are based on signals from simple maintenance indicators and qualitative analysis of underlying data on failures and maintenance. To facilitate generation of maintenance indicators, and make the maintenance analysis more efficient, a powerful and suitable data treatment tool is needed for analysis of the work order history. In the final maintenance decisions, additional decision criteria must be taken into account, and thus a more formal decision analysis is often needed for decision support. (au)

Predictive Maintenance: One key to improved power plant availability

International Nuclear Information System (INIS)

Mobley; Allen, J.W.

1986-01-01

Recent developments in microprocessor technology has provided the ability to routinely monitor the actual mechanical condition of all rotating and reciprocating machinery and process variables (i.e. pressure, temperature, flow, etc.) of other process equipment within an operating electric power generating plant. This direct correlation between frequency domain vibration and actual mechanical condition of machinery and trending process variables of non-rotating equipment can provide the ''key'' to improving the availability and reliability, thermal efficiency and provide the baseline information necessary for developing a realistic plan for extending the useful life of power plants. The premise of utilizing microprocessor-based Predictive Maintenance to improve power plant operation has been proven by a number of utilities. This paper provides a comprehensive discussion of the TEC approach to Predictive Maintenance and examples of successful programs

Maintenance-based prognostics of nuclear plant equipment for long-term operation

Energy Technology Data Exchange (ETDEWEB)

Welz, Zachary; Coble, Jamie; Upadhyaya, Belle; Hines, Wes [University of Tennessee, Knoxville (United States)

2017-08-15

While industry understands the importance of keeping equipment operational and well maintained, the importance of tracking maintenance information in reliability models is often overlooked. Prognostic models can be used to predict the failure times of critical equipment, but more often than not, these models assume that all maintenance actions are the same or do not consider maintenance at all. This study investigates the influence of integrating maintenance information on prognostic model prediction accuracy. By incorporating maintenance information to develop maintenance-dependent prognostic models, prediction accuracy was improved by more than 40% compared with traditional maintenance-independent models. This study acts as a proof of concept, showing the importance of utilizing maintenance information in modern prognostics for industrial equipment.

Automotive Maintenance Data Base for Model Years 1976-1979. Part I

Science.gov (United States)

1980-12-01

An update of the existing data base was developed to include life cycle maintenance costs of representative vehicles for the model years 1976-1979. Repair costs as a function of time are also developed for a passenger car in each of the compact, subc...

Good practices for cost effective maintenance of nuclear power plants

International Nuclear Information System (INIS)

1997-02-01

This publication is organized around five areas that were identified by the utilities and government organizations who contributed to this report as most important to them. They are: Increasing production through maintenance activities related to improved plant material condition, reduced duration of planned outages, use of on-line maintenance and reduced frequency of forced outages; reducing workload through avoiding unnecessary regulatory burden and using reliability centered maintenance and condition monitoring; improving maintenance processes through better planning and scheduling, use of information management systems, graduated work controls, and appropriate post-maintenance testing; improving productivity through better teamwork, greater sharing of resources, and better radiation management associated with maintenance; measuring performance of maintenance activities through such tools as performance measures and benchmarking. Figs, tabs

Status of online maintenance in the world

International Nuclear Information System (INIS)

Mizumachi, Wataru; Kobayashi, Masahide

2009-01-01

In many countries, online maintenance has been already introduced. Especially in US, online maintenance has been introduced to many nuclear plants which has (N+1) redundant safety systems as Japanese plants. There experience will contribute us to discuss how to introduce online maintenance in Japan. In IAEA's nuclear safety criteria and guidance, it is recognized that the outage of one safety system for maintenance is usual operation. This is normal sense in the world. In US, the risk when online maintenance is done is controlled mainly by PRA. We have to discuss how to introduce online maintenance in JAPAN under these conditions in the world. (author)

Reliability-Based Planning of Inspection, Operation and Maintenance for Offshore Oil & Gas Structures and Wind Turbines

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard

2011-01-01

Reliability-based cost-optimal planning of inspection, maintenance and operation has many applications. In this paper applications for planning of inspections for oil & gas jacket structures and of operation and maintenance of offshore wind turbines are described and illustrated by examples....

Optimizing preventive maintenance

International Nuclear Information System (INIS)

DiCola, F.E.

1988-01-01

The traditional approach to preventive maintenance (PM) is based on adherence to manufacturers's requirements and recommended frequencies. When equipment fails, either new procedures are established or the frequency is increased. This leads to an increase in the number of PM activities, overloading not only maintenance resources, but support as well. There is no correlation between more PM and an increase in equipment reliability. More PM may actually induce failures. Reliability-centered maintenance, a new concept in utility maintenance, is based on identifying system/subsystem functions, failures, and dominant failure modes to develop or revise PM tasks. The activities described in this paper are based on actual implementation of this concept on an ongoing project to upgrade the PM program at one of the largest electric utilities in the country. Optimum PM activities are those that, when implemented, will minimize factors that c cause equipment to fail. One technique described illustrates how equipment performance, failure modes, and causes can be related to minimize the occurrence of failures. Operating history and service life of a component are key factors in determining the most effective PM activities, provided that the factors are related to failure modes and causes

Utility based maintenance analysis using a Random Sign censoring model

International Nuclear Information System (INIS)

Andres Christen, J.; Ruggeri, Fabrizio; Villa, Enrique

2011-01-01

Industrial systems subject to failures are usually inspected when there are evident signs of an imminent failure. Maintenance is therefore performed at a random time, somehow dependent on the failure mechanism. A competing risk model, namely a Random Sign model, is considered to relate failure and maintenance times. We propose a novel Bayesian analysis of the model and apply it to actual data from a water pump in an oil refinery. The design of an optimal maintenance policy is then discussed under a formal decision theoretic approach, analyzing the goodness of the current maintenance policy and making decisions about the optimal maintenance time.

Optimization of surface maintenance

International Nuclear Information System (INIS)

Oeverland, E.

1990-01-01

The present conference paper deals with methods of optimizing the surface maintenance of steel-made offshore installations. The paper aims at identifying important approaches to the problems regarding the long-range planning of an economical and cost effective maintenance program. The methods of optimization are based on the obtained experiences from the maintenance of installations on the Norwegian continental shelf. 3 figs

BIM authoring for an image-based bridge maintenance system of existing cable-supported bridges

Science.gov (United States)

Dang, N. S.; Shim, C. S.

2018-04-01

Infrastructure nowadays is increasingly become the main backbone for the metropolitan development in general. Along with the rise of new facilities, the demand in term of maintenance for the existing bridges is indispensable. Recently, the terminology of “preventive maintenance” is not unfamiliar with the engineer, literally is the use of a bridge maintenance system (BMS) based on a BIM-oriented model. In this paper, the process of generating a BMS based on BIM model is introduced in detail. Data management for this BMS is separated into two modules: site inspection system and information management system. The noteworthy aspect of this model lays on the closed and automatic process of “capture image, generate the technical damage report, and upload/feedback to the BMS” in real-time. A pilot BMS system for a cable-supported bridge is presented which showed a good performance and potential to further development of preventive maintenance.

On risk-based operation and maintenance of offshore wind turbine components

International Nuclear Information System (INIS)

Jessen Nielsen, Jannie; Dalsgaard Sorensen, John

2011-01-01

Operation and maintenance are significant contributors to the cost of energy for offshore wind turbines. Optimal planning could rationally be based on Bayesian pre-posterior decision theory, and all costs through the lifetime of the structures should be included. This paper contains a study of a generic case where the costs are evaluated for a single wind turbine with a single component. Costs due to inspections, repairs, and lost production are included in the model. The costs are compared for two distinct maintenance strategies, namely with and without inclusion of periodic imperfect inspections. Finally the influence of different important parameters, e.g. failure rate, reliability of inspections, inspection interval, and decision rule for repairs, is evaluated.

Improvements in valve reliability due to implementation of effective condition monitoring programs

International Nuclear Information System (INIS)

Hale, Stan

2003-01-01

Modern diagnostic systems for motor-operated valves, pneumatic control valves and checkvalves have facilitated a shift in the maintenance philosophy for valves and actuators in nuclear power plants from schedule based to condition-based maintenance (CBM). This shift enables plant management to focus resources and schedule priority on the plant equipment that warrants attention thereby not wasting resources or increasing the human factors risk on equipment that has not degraded. The most recent initiatives combine condition monitoring with risk/safety insights to focus attention and resonances on the right equipment at the right time consistent with each component's safety-significance. The activities of the ASME working groups responsible for nuclear O and M codes have kept pace with the technology and process improvements necessary to maximize the technical and economic benefits of condition based and risk informed maintenance. This paper discusses adoption of valve condition monitoring in the nuclear power industry, changes to ASME codes and standards during the 90's to facilitate adoption of condition monitoring technology for in-service testing and recent efforts to combine risk insights with condition monitoring strategies to achieve the highest level of valve reliability and nuclear safety without over inflating maintenance cost. (author)

Reliability Centered Maintenance (RCM) Methodology and Application to the Shutdown Cooling System for APR-1400 Reactors

Energy Technology Data Exchange (ETDEWEB)

Faragalla, Mohamed M.; Emmanuel, Efenji; Alhammadi, Ibrahim; Awwal, Arigi M.; Lee, Yong Kwan [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

2016-10-15

Shutdown Cooling System (SCS) is a safety-related system that is used in conjunction with the Main Steam and Main or Auxiliary Feedwater Systems to reduce the temperature of the Reactor Coolant System (RCS) in post shutdown periods from the hot shutdown operating temperature to the refueling temperature. In this paper RCM methodology is applied to (SCS). RCM analysis is performed based on evaluation of Failure Modes Effects and Criticality Analysis (FME and CA) on the component, system and plant. The Logic Tree Analysis (LTA) is used to determine the optimum maintenance tasks. The main objectives of RCM is the safety, preserve the System function, the cost-effective maintenance of the plant components and increase the reliability and availability value. The RCM methodology is useful for improving the equipment reliability by strengthening the management of equipment condition, and leads to a significant decrease in the number of periodical maintenance, extended maintenance cycle, longer useful life of equipment, and decrease in overall maintenance cost. It also focuses on the safety of the system by assigning criticality index to the various components and further selecting maintenance activities based on the risk of failure involved. Therefore, it can be said that RCM introduces a maintenance plan designed for maximum safety in an economical manner and making the system more reliable. For the SCP, increasing the number of condition monitoring tasks will improve the availability of the SCP. It is recommended to reduce the number of periodic maintenance activities.

Instrumentation maintenance

International Nuclear Information System (INIS)

Mack, D.A.

1976-09-01

It is essential to any research activity that accurate and efficient measurements be made for the experimental parameters under consideration for each individual experiment or test. Satisfactory measurements in turn depend upon having the necessary instruments and the capability of ensuring that they are performing within their intended specifications. This latter requirement can only be achieved by providing an adequate maintenance facility, staffed with personnel competent to understand the problems associated with instrument adjustment and repair. The Instrument Repair Shop at the Lawrence Berkeley Laboratory is designed to achieve this end. The organization, staffing and operation of this system is discussed. Maintenance policy should be based on studies of (1) preventive vs. catastrophic maintenance, (2) records indicating when equipment should be replaced rather than repaired and (3) priorities established to indicate the order in which equipment should be repaired. Upon establishing a workable maintenance policy, the staff should be instructed so that they may provide appropriate scheduled preventive maintenance, calibration and corrective procedures, and emergency repairs. The education, training and experience of the maintenance staff is discussed along with the organization for an efficient operation. The layout of the various repair shops is described in the light of laboratory space and financial constraints

Structural maintenance planning based on historical data of corroded deck plates of tankers

International Nuclear Information System (INIS)

Garbatov, Y.; Guedes Soares, C.

2009-01-01

A probabilistic maintenance and repair analysis of tanker deck plates subjected to general corrosion is presented. The decisions about when to perform maintenance and repair on the structure are studied. Different practical scenarios are analyzed and optimum repair times are proposed. The optimum repair age and intervals are defined based on the statistical analysis of operational data using the Weibull model and some assumptions about the inspection and time needed for repair. The total cost is calculated in normalized form.

Rotating Machinery Predictive Maintenance Through Expert System

Directory of Open Access Journals (Sweden)

M. Sarath Kumar

2000-01-01

Full Text Available Modern rotating machines such as turbomachines, either produce or absorb huge amount of power. Some of the common applications are: steam turbine-generator and gas turbine-compressor-generator trains produce power and machines, such as pumps, centrifugal compressors, motors, generators, machine tool spindles, etc., are being used in industrial applications. Condition-based maintenance of rotating machinery is a common practice where the machine's condition is monitored constantly, so that timely maintenance can be done. Since modern machines are complex and the amount of data to be interpreted is huge, we need precise and fast methods in order to arrive at the best recommendations to prevent catastrophic failure and to prolong the life of the equipment. In the present work using vibration characteristics of a rotor-bearing system, the condition of a rotating machinery (electrical rotor is predicted using an off-line expert system. The analysis of the problem is carried out in an Object Oriented Programming (OOP framework using the finite element method. The expert system which is also developed in an OOP paradigm gives the type of the malfunctions, suggestions and recommendations. The system is implemented in C++.

Incorrect modeling of the failure process of minimally repaired systems under random conditions: The effect on the maintenance costs

International Nuclear Information System (INIS)

Pulcini, Gianpaolo

2015-01-01

This note investigates the effect of the incorrect modeling of the failure process of minimally repaired systems that operates under random environmental conditions on the costs of a periodic replacement maintenance. The motivation of this paper is given by a recently published paper, where a wrong formulation of the expected cost for unit time under a periodic replacement policy is obtained. This wrong formulation is due to the incorrect assumption that the intensity function of minimally repaired systems that operate under random conditions has the same functional form as the failure rate of the first failure time. This produced an incorrect optimization of the replacement maintenance. Thus, in this note the conceptual differences between the intensity function and the failure rate of the first failure time are first highlighted. Then, the correct expressions of the expected cost and of the optimal replacement period are provided. Finally, a real application is used to measure how severe can be the economical consequences caused by the incorrect modeling of the failure process.

Pavement maintenance scheduling using genetic algorithms

OpenAIRE

Yang, Chao; Remenyte-Prescott, Rasa; Andrews, John D.

2015-01-01

This paper presents a new pavement management system (PMS) to achieve the optimal pavement maintenance and rehabilitation (M&R) strategy for a highway network using genetic algorithms (GAs). Optimal M&R strategy is a set of pavement activities that both minimise the maintenance cost of a highway network and maximise the pavement condition of the road sections on the network during a certain planning period. NSGA-II, a multi-objective GA, is employed to perform pavement maintenance optimisatio...

Tribological diagnostics as a precondition for maintenance

International Nuclear Information System (INIS)

Jolevski, Tome

1999-01-01

The concept of maintenance in one industrial system usually represents a sum of constructions and rules that point out to several facts: 1) over which technical system the maintenance should be applied, 2) when it should be applied and 3) on which way it should be organized. In our real industrial systems the contemporary maintenance of the technical systems is not enough. Also, other contemporary measures whose basic task is to prevent unplanned stoppages as well as damages in the production process are insufficient. The equipment of the technical systems with devices for permanent monitoring of the condition, in other words with devices for technical diagnostic is unsatisfactorily, with a small exemption of the devices for vibration diagnostic monitoring of the condition in real time. The tribological diagnostics, using the procedures and methods without destroying as well as measuring and monitoring the condition of the lubrication devices, allows to find out the real status of the technical systems in operation. On that basic it is possible to undertake correct maintenance measures which would provide promising and safe operation of the technical systems. (Author)

Continuous improvement of operation and maintenance conditions of french PWR nuclear islands

International Nuclear Information System (INIS)

Bitsch, D.

1985-05-01

Improvement of the nuclear island design, to facilitate maintenance and working conditions during plant shutdown, has been a subject of particular attention within the French PWR program. Standardization and industrial concentration created an unusually favourable context for approaching this objective. Progress efforts supported by the feedback of actual operating experience were pursued in the areas of plant layout-equipment installation, and on the design and technology of the component themselves. The progress efforts on the design and technology of the components were pursued along several paths including: - the resistance increase of specific parts submitted to various forms of in-service damage, - the reduction of the extent and duration of work during plant outages and - the reduction of the Occupational Radiation Exposure (ORE), one of the most important axes of development, through the appropriate selection of less releasing materials, the implementation of more efficient decontamination systems and by the use of robots

In vitro maintenance, under slow-growth conditions, of oil palm germplasm obtained by embryo rescue

Directory of Open Access Journals (Sweden)

Julcéia Camillo

2015-05-01

Full Text Available The objective of this work was to evaluate the in vitro maintenance of oil palm (Elaeis guineensis and E. oleifera accessions under slow-growth conditions. Plants produced by embryo rescue were subject to 1/2MS culture medium supplemented with the carbohydrates sucrose, mannitol, and sorbitol at 1, 2, and 3% under 20 and 25±2ºC. After 12 months, the temperature of 20°C reduced plant growth. Sucrose is the most appropriate carbohydrate for maintaining the quality of the plants, whereas mannitol and sorbitol result in a reduced plant survival.

Dynamic decision-making for reliability and maintenance analysis of manufacturing systems based on failure effects

Science.gov (United States)

Zhang, Ding; Zhang, Yingjie

2017-09-01

A framework for reliability and maintenance analysis of job shop manufacturing systems is proposed in this paper. An efficient preventive maintenance (PM) policy in terms of failure effects analysis (FEA) is proposed. Subsequently, reliability evaluation and component importance measure based on FEA are performed under the PM policy. A job shop manufacturing system is applied to validate the reliability evaluation and dynamic maintenance policy. Obtained results are compared with existed methods and the effectiveness is validated. Some vague understandings for issues such as network modelling, vulnerabilities identification, the evaluation criteria of repairable systems, as well as PM policy during manufacturing system reliability analysis are elaborated. This framework can help for reliability optimisation and rational maintenance resources allocation of job shop manufacturing systems.

Using heuristic search for optimizing maintenance plans

International Nuclear Information System (INIS)

Mutanen, Teemu

2012-01-01

This work addresses the maintenance action selection process. Maintenance personnel need to evaluate maintenance actions and costs to keep the machines in working condition. Group of actions are evaluated together as maintenance plans. The maintenance plans as output provide information to the user about which actions to take if any and what future actions should be prepared for. The heuristic search method is implemented as part of general use toolbox for analysis of measurements from movable work machines. Impacts from machine's usage restrictions and maintenance activities are analysed. The results show that once put on a temporal perspective, the prioritized order of the actions is different and provide additional information to the user.

An Enhanced Preventive Maintenance Optimization Model Based on a Three-Stage Failure Process

Directory of Open Access Journals (Sweden)

Ruifeng Yang

2015-01-01

Full Text Available Nuclear power plants are highly complex systems and the issues related to their safety are of primary importance. Probabilistic safety assessment is regarded as the most widespread methodology for studying the safety of nuclear power plants. As maintenance is one of the most important factors for affecting the reliability and safety, an enhanced preventive maintenance optimization model based on a three-stage failure process is proposed. Preventive maintenance is still a dominant maintenance policy due to its easy implementation. In order to correspond to the three-color scheme commonly used in practice, the lifetime of system before failure is divided into three stages, namely, normal, minor defective, and severe defective stages. When the minor defective stage is identified, two measures are considered for comparison: one is that halving the inspection interval only when the minor defective stage is identified at the first time; the other one is that if only identifying the minor defective stage, the subsequent inspection interval is halved. Maintenance is implemented immediately once the severe defective stage is identified. Minimizing the expected cost per unit time is our objective function to optimize the inspection interval. Finally, a numerical example is presented to illustrate the effectiveness of the proposed models.

A risk-based model for maintenance decision support of civil structures using RAMS

NARCIS (Netherlands)

Viana Da Rocha, T. C.; Stipanovic, I.; Hartmann, A.; Bakker, J.

2017-01-01

As a cornerstone of transportation asset management, risk-based approaches have been used to support maintenance decisions of civil structures. However, ambiguous and subjective risk criteria and inconsistency on the use of risk-based approaches can lead to a fuzzy understanding of the risks

Framework for Maintenance Planning

DEFF Research Database (Denmark)

Soares, C. Guedes; Duarte, J. Caldeira; Garbatov, Y.

2010-01-01

the design and during the whole life span of operational use, within an integrated framework founded on risk and reliability based techniques. The document addresses designers, decision makers and professionals responsible for or involved in establishing maintenance plans. The purpose of this document......The present document presents a framework for maintenance planning. Maintenance plays a fundamental role in counteracting degradation effects, which are present in all infrastructure and industrial products. Therefore, maintenance planning is a very critical aspect to consider both during...... is to present maintenance as an integrated approach that needs to be planned, designed, engineered, and controlled by proper qualitative and quantitative techniques. This document outlines the basic premises for maintenance planning and provides the general philosophies that can be followed and points to a best...

Development of an intellectual maintenance management system. Development of trouble detection and troubleshooting evaluation system

International Nuclear Information System (INIS)

Suda, Kazunori; Yoshikawa, Shinji; Tani, Satoshi

1998-03-01

Many research activities are conducted to enhance cost performance and safety of nuclear power plants operation and maintenance. Concept of autonomous operating system to equal the role of operators and of maintenance personnel with artificial intelligence and autonomous robots has been developed. An intellectual maintenance management system has been developed to be equipped with decision making functions of maintenance personnel. The intellectual maintenance management system is in charge of maintenance function of an autonomous plant, which consists of plant-wide monitoring, evaluation of component integrity, and scheduling of maintenance activities. In other words, this system should be equipped with preventive maintenance and corrective maintenance functions those are currently loaded on personnel. In this report, we discussed condition monitoring maintenance in the preventive maintenance. We also reported a sensor validation system development for machinery condition monitoring and diagnosis. We adopted distributed and cooperative system construction technique, which is expected recently in applications to large-scale plants. This system has inter-agent communication function for signal transmission and reception among distributed physics models of machineries. The system has been constructed for water/steam system of the LMFBR power plant. The system has been validated to be capable of cooperative sensor validation by the distributed set of agents, with quantitative indication of sensor deviation based on a newly developed fuzzy algorithm with inter-agent cooperation. The derived reference parameter value from the inter-agent evaluations also stands for the alternative measurement to the malfunctioned sensor. (author)

An All-Recombinant Protein-Based Culture System Specifically Identifies Hematopoietic Stem Cell Maintenance Factors

Directory of Open Access Journals (Sweden)

Aki Ieyasu

2017-03-01

Full Text Available Hematopoietic stem cells (HSCs are considered one of the most promising therapeutic targets for the treatment of various blood disorders. However, due to difficulties in establishing stable maintenance and expansion of HSCs in vitro, their insufficient supply is a major constraint to transplantation studies. To solve these problems we have developed a fully defined, all-recombinant protein-based culture system. Through this system, we have identified hemopexin (HPX and interleukin-1α as responsible for HSC maintenance in vitro. Subsequent molecular analysis revealed that HPX reduces intracellular reactive oxygen species levels within cultured HSCs. Furthermore, bone marrow immunostaining and 3D immunohistochemistry revealed that HPX is expressed in non-myelinating Schwann cells, known HSC niche constituents. These results highlight the utility of this fully defined all-recombinant protein-based culture system for reproducible in vitro HSC culture and its potential to contribute to the identification of factors responsible for in vitro maintenance, expansion, and differentiation of stem cell populations.

Research and Development of a Network-Based Intelligent Maintenance Information System

Institute of Scientific and Technical Information of China (English)

ZANG Tie-gang; YANG Ming-zhong; GUO Shun-sheng

2003-01-01

A maintenance information system is an important part of equipment management. An intelli gent maintenance information system ( IMIS) is a synthesis of network technology, information technology and intelligent technology. The IMIS is used to finish flexible maintenance decision-making and fast maintenance planning, which helps enterprises to effectively reduce maintenance cost and increase working efficiency. Because the IMIS integrates advanced technologies, its performance is better than a traditional one.The difference between an IMIS and a traditional maintenance information system, and the functions, structure, important realizations, and application of an IMIS are discussed in this paper.

Research and development of remote maintenance equipment for ITER divertor maintenance

International Nuclear Information System (INIS)

Takeda, Nobukazu; Kakudate, Satoshi; Nakahira, Masataka

2005-02-01

To facilitate easy remote maintainability, the ITER divertor is divided into 60 cassettes, which are transported in the toroidal and radial directions for replacement through maintenance ports located every 90 degrees using the divertor remote maintenance equipment such as in- and ex-vessel transporters. The cassette of 25 tons has to be transported and installed in the vacuum vessel with a positioning accuracy less than 2 mm in the limited space of the vacuum vessel and maintenance port under the intense gamma radiation field. Based on these requirements, the following design and tests were performed. (1) Link mechanism was studied to apply to the transportation of the heavy cassette in the restricted space. A compact mechanism with links for transportation of heavy cassette is designed through the optimization of the link angle taking account of space requirement and force efficiency. As a test result, the lifting capacity of 30 tons (larger than the cassette weight of 25 tons) using two link mechanisms has been demonstrated in the limited space. (2) Compact link mechanism was also studied to apply for locking of the cassette through the optimization of the link angle taking account of space requirement and force efficiency. As a test result, the final positioning accuracy of 0.03 mm for the 25 tons-cassette installation on the vacuum vessel from the initial positioning error of 5 mm has been demonstrated, so that the test result satisfies the requirement less than 2 mm using the link mechanisms in the limited space. (3) Sensor-based control using simple sensors such as optical fiber for divertor maintenance was tested using the full-scale mock-up divertor cassette and remote maintenance equipment. As a result, it is found that the positioning accuracy of 0.16 mm has been achieved by the optical fiber sensor and this value is sufficient for sensor-based control. In addition, the maintenance operation has been carried out through the human-machine interface

e-Learning Application for Machine Maintenance Process using Iterative Method in XYZ Company

Science.gov (United States)

Nurunisa, Suaidah; Kurniawati, Amelia; Pramuditya Soesanto, Rayinda; Yunan Kurnia Septo Hediyanto, Umar

2016-02-01

XYZ Company is a company based on manufacturing part for airplane, one of the machine that is categorized as key facility in the company is Millac 5H6P. As a key facility, the machines should be assured to work well and in peak condition, therefore, maintenance process is needed periodically. From the data gathering, it is known that there are lack of competency from the maintenance staff to maintain different type of machine which is not assigned by the supervisor, this indicate that knowledge which possessed by maintenance staff are uneven. The purpose of this research is to create knowledge-based e-learning application as a realization from externalization process in knowledge transfer process to maintain the machine. The application feature are adjusted for maintenance purpose using e-learning framework for maintenance process, the content of the application support multimedia for learning purpose. QFD is used in this research to understand the needs from user. The application is built using moodle with iterative method for software development cycle and UML Diagram. The result from this research is e-learning application as sharing knowledge media for maintenance staff in the company. From the test, it is known that the application make maintenance staff easy to understand the competencies.

Estimating cost per lane mile for routine highway operations and maintenance

Science.gov (United States)

2011-01-01

The disparity between maintenance budgets and maintenance requirements causes agencies to make difficult choices : about maintenance priorities. There is a growing need to effectively link maintenance costs and condition to provide clear : evidence o...

Optimisation of maintenance concept choice using risk-decision factor - a case study

Science.gov (United States)

Popovic, Vladimir M.; Vasic, Branko M.; Rakicevic, Branislav B.; Vorotovic, Goran S.

2012-10-01

The design of maintenance system and the corresponding logistic support is a very complex process, during which the aim is to find the compromise solutions regarding the relations among different maintenance procedures and the ways of their implementation. As a result of this, various solutions can be adopted, since this is conditioned by a series of important factors and criteria, which can be contradictory sometimes. There are different perspectives on ways of solving practical maintenance problems, that is dilemmas when it comes to the choice of maintenance concept. The principal dilemma is how and when to decide on carrying out maintenance procedures. Should the decision be based on theoretical grounds or experience, how does one reconcile those two extremes, who is to decide upon this? In this article we have offered one, basically new solution as a possibility for maintenance concept choice, based on a significant modification of the widely used failure modes and effects analysis (FMEA) method. This solution is risk-decision factor (RDF). This is a result of seven parameters (of different importance and weight) that have the key impact on the process of production and logistic support. The application of this factor is illustrated by the example of planning, organisation and functioning of the maintenance system applied in The Institute for Manufacturing Banknotes and Coins (ZIN) in Belgrade.

Software evolution and maintenance

CERN Document Server

Tripathy, Priyadarshi

2014-01-01

Software Evolution and Maintenance: A Practitioner's Approach is an accessible textbook for students and professionals, which collates the advances in software development and provides the most current models and techniques in maintenance.Explains two maintenance standards: IEEE/EIA 1219 and ISO/IEC14764Discusses several commercial reverse and domain engineering toolkitsSlides for instructors are available onlineInformation is based on the IEEE SWEBOK (Software Engineering Body of Knowledge)

Decision Support System for Condition Monitoring Technologies

NARCIS (Netherlands)

Mouatamir, Abderrahim

2018-01-01

The technological feasibility of a condition-based maintenance (CBM) policy is intrinsically related to the suitable selection of condition monitoring (CM) technologies such as vibration- and oil analysis or other non-destructive testing (NDT) techniques such as radiographic- and magnetic particle

New conceptual method in maintenance with application in cryogenics pilot plant (CPP)

International Nuclear Information System (INIS)

Anghel, Vasile

2006-01-01

Full text: This study concluded with a series of suggestions concerning the methodology of maintaining a Cryogenics Nuclear Plant where the maintenance is either fundamental or only of importance. The implementation of this methodology can be achieved in two main steps. The first step concerns the conception of the scientific basis for maintenance, while the second step regards the implementation. The first step describes the management of maintenance in conditions of quality, risk and cost constraints. The conditions are established on the basis of a project of research in maintenance. The second step notifies the aspects of design and technology in maintenance of nuclear industrial units. The nuclear complex technical systems of the Cryogenics Pilot Plant at ICSI - Rm Valcea implies the development of some dedicated software, to ensure the designing, realization and operation of the plant, and prototypes of integrated software modules, to ensure the systems operation during of the life cycle. The implementation method is based on vibration analyses and mechanical studies while a flexible data acquisition system for monitoring, and control must be developed as a platform to ensure a more precise diagnosis and prediction of machinery malfunction. With a flexible data acquisition and analysis system in operation it is possible to easily increase the number of input channels. (author)

Human Error Probability Assessment During Maintenance Activities of Marine Systems

OpenAIRE

Rabiul Islam; Faisal Khan; Rouzbeh Abbassi; Vikram Garaniya

2018-01-01

Background: Maintenance operations on-board ships are highly demanding. Maintenance operations are intensive activities requiring high man–machine interactions in challenging and evolving conditions. The evolving conditions are weather conditions, workplace temperature, ship motion, noise and vibration, and workload and stress. For example, extreme weather condition affects seafarers' performance, increasing the chances of error, and, consequently, can cause injuries or fatalities to personne...

Improvement of testing and maintenance based on fault tree analysis

International Nuclear Information System (INIS)

Cepin, M.

2000-01-01

Testing and maintenance of safety equipment is an important issue, which significantly contributes to safe and efficient operation of a nuclear power plant. In this paper a method, which extends the classical fault tree with time, is presented. Its mathematical model is represented by a set of equations, which include time requirements defined in the house event matrix. House events matrix is a representation of house events switched on and off through the discrete points of time. It includes house events, which timely switch on and off parts of the fault tree in accordance with the status of the plant configuration. Time dependent top event probability is calculated by the fault tree evaluations. Arrangement of components outages is determined on base of minimization of mean system unavailability. The results show that application of the method may improve the time placement of testing and maintenance activities of safety equipment. (author)

METHODOLOGY OF DETERMINATION OF QUALITY INDEX OF MAINTENANCE SERVICE SYSTEM OF POWER EQUIPMENT OF TRACTION SUBSTATIONS

Directory of Open Access Journals (Sweden)

O.O. Matusevych

2016-03-01

Full Text Available Purpose. The purpose of this paper is development of methodology for definition of a quality system of maintenance and repair (M and P power equipment of traction substations (TS of electrified railways operating under conditions of uncertainty based on expert information. Methodology. The basic tenets of the theory of fuzzy sets and marks, linguistic and interval estimates of experts were applied to solve this problem. Results. Analysis of the existing diversity of approaches to development of modern methods of improvement of M and P allows us to conclude that the improvement in the quality of the system is achieved by solving individual problems increase the operational reliability of power equipment of traction substations in the following main interrelated areas. There are technical, economic and organizational. The basis of the quality evaluation system is initial data and expertise developed version of the document formalized quality evaluation of electrical equipment of traction substations by experts. The choice of determining the level of Quality service system based on the marks, linguistic and interval estimates of experts, which are reflected in quantitative and / or qualitative form was done. The possible options for expert data presentation and their corresponding quantitative methods of calculating the integral index of quality improvement system maintenance and P of traction substations were described. The methodology and the method of assessing the quality of system maintenance and P of TS allows quickly respond to changing operating conditions of power equipment of traction substations, and to determine the most effective strategies for maintenance of electrical and P TS under conditions of uncertainty functioning distance electricity. Originality. The method of a systematic approach to improve the quality of the system maintenance and P of power equipment of traction substation under conditions of uncertainty based on expert

Joint Optimization of Preventive Maintenance and Spare Parts Inventory with Appointment Policy

Directory of Open Access Journals (Sweden)

Jing Cai

2017-01-01

Full Text Available Under the background of the wide application of condition-based maintenance (CBM in maintenance practice, the joint optimization of maintenance and spare parts inventory is becoming a hot research to take full advantage of CBM and reduce the operational cost. In order to avoid both the high inventory level and the shortage of spare parts, an appointment policy of spare parts is first proposed based on the prediction of remaining useful lifetime, and then a corresponding joint optimization model of preventive maintenance and spare parts inventory is established. Due to the complexity of the model, the combination method of genetic algorithm and Monte Carlo is presented to get the optimal maximum inventory level, safety inventory level, potential failure threshold, and appointment threshold to minimize the cost rate. Finally, the proposed model is studied through a case study and compared with both the separate optimization and the joint optimization without appointment policy, and the results show that the proposed model is more effective. In addition, the sensitivity analysis shows that the proposed model is consistent with the actual situation of maintenance practices and inventory management.

Evaluation of artillery equipment maintenance support capability based on grey clustering

Science.gov (United States)

Zhai, Mei-jie; Gao, Peng

2017-12-01

This paper, the theory and method of evaluating the capability of equipment maintenance support in China and abroad are studied, from the point of view of the combat task of artillery troops and the strategic attachment in the future military struggle. This paper establishes the framework of the evaluation Index system of the equipment maintenance support capability of the artillery units, and applies the grey clustering method to the evaluation of the equipment maintenance support capability of the artillery units, and finally evaluates the equipment maintenance and support capability of the artillery brigade as an example, and analyzes the evaluation results. This paper finds out the outstanding problems existing in the maintenance and support of military equipment, and puts forward some constructive suggestions, in order to improve the status of military equipment maintenance and support and improve the level of future equipment maintenance.

The virtual maintenance system: a computer-based support tool for robust design, product monitoring, fault diagnosis and maintenance planning

NARCIS (Netherlands)

van Houten, Frederikus J.A.M.; Kimura, F.

2000-01-01

Digital (geometric) product models can be used for maintainability analysis and maintenance planning. It is not feasible to build digital product models for maintenance purposes only, but if a digital product model is available, it may be used to support many maintenance-related engineering tasks.

Partial maintenance of auditory-based cognitive training benefits in older adults

Science.gov (United States)

Anderson, Samira; White-Schwoch, Travis; Choi, Hee Jae; Kraus, Nina

2014-01-01

The potential for short-term training to improve cognitive and sensory function in older adults has captured the public’s interest. Initial results have been promising. For example, eight weeks of auditory-based cognitive training decreases peak latencies and peak variability in neural responses to speech presented in a background of noise and instills gains in speed of processing, speech-in-noise recognition, and short-term memory in older adults. But while previous studies have demonstrated short-term plasticity in older adults, we must consider the long-term maintenance of training gains. To evaluate training maintenance, we invited participants from an earlier training study to return for follow-up testing six months after the completion of training. We found that improvements in response peak timing to speech in noise and speed of processing were maintained, but the participants did not maintain speech-in-noise recognition or memory gains. Future studies should consider factors that are important for training maintenance, including the nature of the training, compliance with the training schedule, and the need for booster sessions after the completion of primary training. PMID:25111032

Autonomous and professional maintenance in metallurgical enterprise as activities within total productive maintenance

Directory of Open Access Journals (Sweden)

B. Gajdzik

2014-04-01

Full Text Available The content of this publication consists of notions connected with Total Productive Maintenance (TPM in metallurgical enterprise. The basic areas of devices condition management through Autonomous and Professional Maintenance are described here. Mentioned areas of activities are performed in metallurgical enterprise ArcelorMittal Poland within pillars of World Class Manufacturing (WCM. The aims of UR programs are to maintain the basic functionality of the devices and decrease the number of failures in order to reach improvement of production efficiency.

General Guidelines for Remote Operation and Maintenance of Pyroprocess Equipment

Energy Technology Data Exchange (ETDEWEB)

Kim, S. H.; Park, B. S.; Park, H. S.; Lee, H. J.; Choi, C. W.; Lee, J. K

2007-12-15

As the pyroprocess handle the high radioactive materials, a high radioactive material handling facility required high safety, radioactive shielding, strict quality control, and the remote handling equipment of high technology. This report describes the guidelines of for pyroprocess based the design guides for radioactive material handling facility and equipment from American Nuclear Society(ANS), design guidelines for remotely maintained equipment from Oak Ridge National Laboratory(ORNL), and the experience of design for ACP equipment installed at the ACPF(Advanced Conditioning Process Facility). The General guidelines in this report are as follows. The General guidelines for remote operation and maintenance of pyroprocess equipment: Pyroprocess, Remote handling equipment for pyroprocess, General guide for remote operation and maintenance, general guidelines for the design of remotely operated and maintained equipment, Estimation and analysis for remote maintenance.

Lean thinking for a maintenance process

Directory of Open Access Journals (Sweden)

Sherif Mostafa

2015-01-01

Full Text Available The maintenance process shares significant operating costs in an organisation. Lean thinking can be incorporated into maintenance activities through applying its principles and practices/tools. Lean maintenance (LM is a prerequisite for lean manufacturing systems. This research proposes a new structure for LM process based on a systematic literature review of a significant number of related articles that were published on LM. The process structure is designed based on the five lean principles to guide and support organisations to pursue maintenance excellence. This study establishes a scheme for LM tools that are structured into 2 level 4 bundles and 26 lean practices/tools and develops a House of Waste (HoW to demonstrate the association between maintenance wastes and the LM tools. With a successful accomplishment of the proposed scheme, the performance of a maintenance department can create more improvement opportunities over time to reach the maintenance excellence status.

Bridge Condition Assessment based on Vibration Responses of Passenger Vehicle

International Nuclear Information System (INIS)

Miyamoto, Ayaho; Yabe, Akito

2011-01-01

In this paper, we propose a new method of assessing the condition of existing short- and medium-span reinforced/prestressed concrete bridges based on vibration monitoring data obtained from a public bus. This paper not only describes details of a prototype monitoring system that uses information technology and sensors capable of providing more accurate knowledge of bridge performance than conventional ways but also shows a few specific examples of bridge condition assessment based on vehicle vibrations measured by using an in-service public bus equipped with vibration measurement instrumentation. This paper also describes a sensitivity analysis of deteriorating bridges based on simulation of the acceleration response of buses conducted by the 'substructure method' employing a finite element model to verify the above bridge performance results. The main conclusions obtained in this study can be summarized as follows: (1) Because the vibration responses of passenger vehicles, such as buses, have a good linear relationship with the vibration responses of the target bridges, the proposed system can be used as a practical monitoring system for bridge condition assessment. (2) The results of sensitivity analysis performed by the substructure method show that bus vibration responses are useful for evaluating target bridge performance. (3) The proposed method was applied to a network of real bridges in a local area to evaluate its effectiveness. The results indicate that the proposed method can be used to prioritize the repair/strengthening works of existing bridges based on various vibration information in order to help bridge administrators establish rational maintenance strategies.

Optimum Maintenance Strategies for Highway Bridges

DEFF Research Database (Denmark)

Frangopol, Dan M.; Thoft-Christensen, Palle; Das, Parag C.

As bridges become older and maintenance costs become higher, transportation agencies are facing challenges related to implementation of optimal bridge management programs based on life cycle cost considerations. A reliability-based approach is necessary to find optimal solutions based on minimum...... expected life-cycle costs or maximum life-cycle benefits. This is because many maintenance activities can be associated with significant costs, but their effects on bridge safety can be minor. In this paper, the program of an investigation on optimum maintenance strategies for different bridge types...... is described. The end result of this investigation will be a general reliability-based framework to be used by the UK Highways Agency in order to plan optimal strategies for the maintenance of its bridge network so as to optimize whole-life costs....

For whom does it work? moderators of outcome on the effect of a transdiagnostic internet-based maintenance treatment after inpatient psychotherapy: randomized controlled trial.

Science.gov (United States)

Ebert, David Daniel; Gollwitzer, Mario; Riper, Heleen; Cuijpers, Pim; Baumeister, Harald; Berking, Matthias

2013-10-10

Recent studies provide evidence for the effectiveness of Internet-based maintenance treatments for mental disorders. However, it is still unclear which participants might or might not profit from this particular kind of treatment delivery. The study aimed to identify moderators of treatment outcome in a transdiagnostic Internet-based maintenance treatment (TIMT) offered to patients after inpatient psychotherapy for mental disorders in routine care. Using data from a randomized controlled trial (N=400) designed to test the effectiveness of TIMT, we performed secondary analyses to identify factors moderating the effects of TIMT (intervention) when compared with those of a treatment-as-usual control condition. TIMT involved an online self-management module, asynchronous patient-therapist communication, a peer support group, and online-based progress monitoring. Participants in the control condition had unstructured access to outpatient psychotherapy, standardized outpatient face-to-face continuation treatment, and psychotropic management. Self-reports of psychopathological symptoms and potential moderators were assessed at the start of inpatient treatment (T1), at discharge from inpatient treatment/start of TIMT (T2), and at 3-month (T3) and 12-month follow-up (T4). Education level, positive outcome expectations, and diagnoses significantly moderated intervention versus control differences regarding changes in outcomes between T2 and T3. Only education level moderated change differences between T2 and T4. The effectiveness of the intervention (vs control) was more pronounced among participants with a low (vs high) education level (T2-T3: B=-0.32, SE 0.16, P=.049; T2-T4: B=-0.42, SE 0.21, P=.049), participants with high (vs low) positive outcome expectations (T2-T3: B=-0.12, SE 0.05, P=.02) and participants with anxiety disorder (vs mood disorder) (T2-T3: B=-0.43, SE 0.21, P=.04). Simple slope analyses revealed that despite some subgroups benefiting less from the

Maintenance-Ready Web Application Development

Directory of Open Access Journals (Sweden)

Ion IVAN

2016-01-01

Full Text Available The current paper tackles the subject of developing maintenance-ready web applications. Maintenance is presented as a core stage in a web application’s lifecycle. The concept of maintenance-ready is defined in the context of web application development. Web application maintenance tasks types are enunciated and suitable task types are identified for further analysis. The research hypothesis is formulated based on a direct link between tackling maintenance in the development stage and reducing overall maintenance costs. A live maintenance-ready web application is presented and maintenance related aspects are highlighted. The web application’s features, that render it maintenance-ready, are emphasize. The cost of designing and building the web-application to be maintenance-ready are disclosed. The savings in maintenance development effort facilitated by maintenance ready features are also disclosed. Maintenance data is collected from 40 projects implemented by a web development company. Homogeneity and diversity of collected data is evaluated. A data sample is presented and the size and comprehensive nature of the entire dataset is depicted. Research hypothesis are validated and conclusions are formulated on the topic of developing maintenance-ready web applications. The limits of the research process which represented the basis for the current paper are enunciated. Future research topics are submitted for debate.