Maintenance decision support by introducing decision modelling and using condition monitoring information

In the area of reliability centred maintenance (RCM), VTT Industrial Automation has focused in the development and application of an experience based reliability centred maintenance approach. As a part of the R&D programme at Barsebäck Kraft AB, reliability and maintenance optimisation studies were conducted by evaluating existing maintenance programmes at the plant using this approach. VTT Industrial Automation contributed to the development of the methodology for systematic maintenance analysis and steering and review of its application by plant personnel in the evaluation of the maintenance action programme of the hydraulic scram system. In order to limit analysis resources in this study, a decision analysis approach was used to rank some 1400 items in this standby safety system, and the most significant component places of them were selected as analysis significant items. The experince based RCM study resulted in proposals for shortening some preventive maintenance intervals, the introduction of additional preventive maintenance actions and the suggestion of additional condition monitoring, to reduce the number of recurrent faults. The modern condition monitoring and signal processing can be useful in prevention of failures, and in timing and improving the cost-effectiveness of maintenance. Condition monitoring can enter the Maintenance Management in existing plants in two-ways: 1) long-term maintenance strategy planning, where the important equipment places for condition monitoring are identified, and 2) short-term maintenance planning and decision-making based on condition monitoring information. The paper will, as a background for the co-operation between VTT Automation and HRP in the field of maintenance decision support, outline: 1) A description of application of the decision analysis approach to rank the 1400 items of the above mentioned hydraulic scram system for selection of the most significant component places for further detailed analysis. A similar decision analytic approach is planned to be defined for assessment of the importance of different equipment places for implementation of condition monitoring as a part of the maintenance strategy evaluation of existing plants. 2) A plan of a survey of the collection and management of condition monitoring information for short-term maintenance planning at several Nordic nuclear power plants.