Over the past ten to fifteen years, all of the Canadian CANDU owner/operators and AECL have been involved in Plant Life Management (PLiM) programmes and activities. The PLiM programmes have used various terminology (such as Life Cycle Management and Integrated Age Management) and there have been some variations in detailed activities, as reflected by various ageing issues and utility practices. Overall the effort has been primarily focused to ensure that CANDU plants will operate successfully and reliably through their design life and to preserve the option to extend plant life. Comprehensive CANDU Plant Life Management (PLIM) programmes have been developed from the operations knowledge gained from the Pickering A, and Bruce A stations, and from the four original CANDU 6 plants. In addition relevant information from the CANDU industry research and development programmes, and other national and international sources have been used.

Processes to systematically identify and evaluate the critical systems, structures, and components (CSSC’s) in Canadian HWRs have been implemented. Ageing assessments involving evaluation of degradation mechanisms that could affect fitness for service for their planned life, have been performed for many CSSCs. Plans have been developed to ensure that plant surveillance, inspection and maintenance programmes monitor and mitigate component degradation important for plant life attainment. There is also effort to incorporate ongoing improvement in equipment reliability programmes such suggested in the INPO AP-913 guideline on Equipment Reliability.

As CANDU plants in Canada continue to age, new challenges are being identified and fed — back into improvements in both the Ageing Assessments themselves and to the important link between PLiM programmes and business planning. PLiM is giving new capability and insight into O&M challenges, that is being used to help improve current plant performance. For instance, some CANDU owner/operators are considering extending duration between outages and PLiM considerations have been a significant element in evaluating the changes. The extension of PLiM techniques to facilitate planning of major plant modifications is becoming more important particularly now that several utilities are embarking on major life extension projects, via refurbishment programmes.

The following is a brief summary of recent PLiM activities in Canada.