Effective ageing management requires a team approach in the application of a systematic ageing management process, Safety Reports Series No. 15, IAEA, Vienna (1999), which is an adaptation of Deming’s ‘PLAN-DO-CHECK-ACT’ cycle to ageing management of an SSC.

A comprehensive understanding of a component, its ageing degradation and the effects of this degradation on the component’s ability to perform its design functions are the BASIS and a prerequisite for a systematic ageing management process. This understanding is derived from: knowledge of the design basis; the design and fabrication data (including material properties and specified service conditions); the operation and maintenance history (including commissioning and surveillance); inspection results; and generic operating experience and research results.

The PLAN activity in the ageing management process is aimed at maximizing the effectiveness of ageing management through the coordination of all programmes and activities that relate to managing the ageing of a component. It includes the identification and documentation of applicable regulatory requirements, operating limits and design assumptions, relevant programmes and activities and their respective roles in the ageing management process, as well as a description of the mechanisms used for programme coordination and continuous improvement. The DO activity of the ageing management process is aimed at minimizing expected component degradation through the operation/use of the component in accordance with operating procedures and limits. The goal of the CHECK activity in the ageing management process is the timely detection and characterization of any significant degradation through component inspection and monitoring and the assessment of observed degradation to determine the type and timing of any corrective actions. The ACT activity in the process is aimed at the timely mitigation/correction of component degradation through appropriate maintenance and design modifications, including component repair and replacement.

The closed loop of the generic ageing management process indicates the need for continuous improvement of a component specific ageing management programme based on the current understanding of component ageing and on the results of self-assessment and peer reviews. Such an ageing management programme is a mixture of component specific ageing management actions designed to minimize, detect and mitigate ageing degradation before component safety margins are compromised.

This mixture reflects the level of understanding of component ageing, the available technology, the regulatory/licensing requirements, and considerations and objectives relating to plant life management. A low level of understanding of ageing of an important component requires careful monitoring because of high uncertainty in predicting the rate of degradation. The feedback of experience is essential in order to provide for ongoing improvement in the understanding of component ageing and in the effectiveness of the ageing management programme. The identification of unanticipated ageing phenomena and the development of appropriate ageing management actions for the benefit of all nuclear power plants depends, in particular, on the timely feedback of operating experience.