This publication provides an overview of the various PLiM methodologies, technologies and

processes for HWRs. Implementation of a systematic and comprehensive PLiM programme,

such as that outlined in this report, goes a long way towards meeting the overall goal of HWR

owners/operator to successfully achieve design life and LTO.

• PLiM programmes should integrate and improve current plant maintenance, surveillance and inspection programmes as these programmes are the primary means for managing ageing processes.

• PLiM programmes serve to aid in the development of sound technical and economic bases for the attainment of design life and preserve the option for LTO. PLiM will facilitate conditions where LTO becomes a realistic option in terms of safety and economics.

• PLiM programmes may be generally planned using experience from NPPs worldwide, but plant-specific PLiM programmes are required. While there are elements of HWR PLiM that are generic, it should be recognized that each NPP is unique and hence, this uniqueness of plant history and its ageing-related programmes need to be considered in detail.

• Effective PLiM programme is aided by complete and accurate documentation on important SSCs. This includes information on SSC design, materials, treatments, manufacturers and modifications. Comprehensive documentation allows operators and regulators to follow the progress of ageing and the effectiveness of any mitigating actions in NPPs.

• Data keeping of a complete set of baseline inspection/testing data for critical SSC’s is an essential prerequisite to allow trend analysis and prediction of critical SCC’s remaining service life for an effective PLiM programme.

• PLiM programmes are dependent on the availability of qualified, well-trained NPP personnel with a questioning and interactive attitude.

• Operating experience is an important element of effective NPP’s PLiM strategy.

• Historical inspection, testing and operating data related to critical SSC’s shall be available for a long period of time because such data are used as input for life assessment, condition assessment and LTO studies. HWR owner/operators must monitor and respond to rapid changes of software and hardware technology in order to maintain availability of essential data for PLiM and LTO Programmes.

• Knowledge management is essential for safe and economical operation of NPPs, especially so for LTO.

• R&D is essential in such an evolving sector as NPP ageing research. It is necessary to continuously investigate the ageing phenomena and mitigating measures by enhancing the evaluation technology and inspection techniques, as well as collecting actual plant data and knowledge obtained from R&D results. Regulators and operators must be aware of R&D results concerning ageing of SSCs, and their impact on safety and economic issues.

• For new designs, PLiM technology should be considered during the design phase, and carried on through construction, commissioning and operation.

• Management systems envelops all elements of plant performance, safety culture and PLiM programme. Degradation in the management infrastructure will thus impact the total business plan.

• Proactive and continually improving trend in safety performance of the plant, upgrading and maintenance of human resources is essential for PLiM and LTO.

• PLiM programmes hould be linked to the station business plan.

• Each HWR owner/operators should implement a systematic and comprehensive PLiM programme at the earliest possible time in the life of the plant, to provide on-going assurance that ageing effects are adequately addressed and traceable. Tighter exchange of information on PLiM methodology, OPEX and practices is beneficial to LWR and HWR owners/operators

• Periodically, review the programme in light of the progress achieved or assessment made and experience gained. As and when necessary, refine/revise the plan.

• PSR should be used as an efficient tool for PLiM programme for LTO.

• All necessary documentation should be validated to confirm the current plant configuration. Documentation management is an important task within PLiM. Some utilities have a configuration management service dedicated to this activity in their organization.

• It is important to also recognize that the reliability of secondary side SSCs will become important as NPPs operate for PLiM. Although such SSCs may be adequately managed for ageing effects (e. g. replacement), their contribution to overall costs have to be considered in the business case for LTO. Extensive replacement and refurbishment tasks may become common place in the future.

• Operators should obtain regulatory feedback on their PLiM programmes in order to ensure safety issues have been duly considered.

• A good practice for transferring technical excellence is to involve NPP employees during major replacement projects within PLiM under the leadership of experienced personnel. Young employees will thus be motivated to acquire essential knowledge through participation.

• The HWR owners/operators of the new plants should consider the scope of commissioning and inaugural inspection programmes and extend it as required to meet the PLiM programme prerequisites.