Development of maintenance strategies for a nuclear power plant

The development of maintenance strategies for a nuclear power plant originates from the fundamental objectives of the power company and societal acceptance. They are production and asset risk management objectives. In our approach, the fundamental objectives are transferred into strategic plant and maintenance objectives. They are implemented into the maintenance programme by determination of the risk importance of the equipment through an equipment classification, each class associated with a functional requirement. The selection of the maintenance tasks and strategies at the Loviisa plant should be such that the requirement specification is met. The selection is based on systematic use of a logic tree, experience feedback data and engineering judgement. Feedback of operating and maintenance experience is crucial for the continuous improvement of the cost-effectiveness of maintenance and plant performance and updating the maintenance programme. Definition of structured maintenance strategies and data for the plant information system is required to facilitate such performance monitoring by appropriate indicators. Thus also human errors were systematically analysed using plant maintenance history data. This improved the knowledge of errors for reduction of them and their effects such as common cause failures and rework in relation to maintenance activities.