Maintenance Optimization – Predictive vs. Preventive Maintenance

Abstract

The Long Term Operation Policy for nuclear plants poses new technical challenges on the power industry, since the plants need to be operated reliably for 50 and more years. It is therefore necessary to deal with the degradation behavior of equipment and its predictability in order to reduce maintenance costs and ensure high safety and high availability at the same time.For this reason an effective maintenance strategy needs to be applied for the surveillance of possible aging effects and preventive measures need to be implemented to ensure the necessary technical basis for maintaining safety margins throughout the plant.In case of passive mechanical components maintenance and surveillance programs shall be based on a reliable condition based degradation assessment. The AREVA concept based on a condition based degradation assessment methodology by applying dedicated corrosion and degradation codes in combination with inspection feedback trending.Maintenance needs for active components (e.g. valves, pumps, etc.) can be assessed based on industry experience regarding symptoms and root causes of system malfunctions. The active components concepts and solutions provide the technological basis for predictive/prognostics capabilities by providing a range of reliability performance indicators for key power plant components.The methodology applied for the assessment of active components which are not online monitored is based on the Reliability Centered Maintenance (RCM) approach, with the objective to optimize the resources available for maintenance in a power plant. It provides the technological basis for predictive/prognostics capabilities by providing a range of reliability performance indicators for huge range of power plant components.This respective software platform with integrated monitoring tools is designed to manage aging issues and life cycle management activities with the objective to optimize maintenance programs. The data are securely stored in a single source database. This computerized monitoring and lifetime surveillance system makes it possible to efficiently keep a lifetime consumption record as a basis for maintenance and repair strategies.