The present report references a variety of other IAEA publications that have been developed in the IAEA project on Safety Aspects of NPP Ageing. Some of these deal exclusively with HWR components; others include HWR components in a report that also includes light water reactor (LWR) components. For background, the project and its main products, including the previously issued programmatic guidelines, are summarized in this section.

The IAEA initiated information exchange on safety aspects of NPP ageing in 1985 to increase awareness of the emerging safety issue relating to physical ageing of plant SSCs. In 1989 a systematic project was begun aimed at assisting Member States in understanding ageing of SSCs important to safety and in effective ageing management of these SSCs in order to ensure their integrity and functional capability throughout their service life. This project integrated information on the evaluation and management of safety aspects of NPP ageing generated by Member States into a common knowledge base, derives guidance, and assists Member States in the application of this guidance. Main publications of the project [1-14, 20, 21] fall into five groups. Figure 2 shows the stature of IAEA publications related with ageing management and PLiM.

Awareness

Following the first International Conference on Safety Aspects of Ageing and Maintenance of Nuclear Power Plants [1] which was organized by the IAEA in 1987, increased awareness of physical ageing of SSCs and its potential safety impact was achieved by the development and wide dissemination in 1990 of IAEA-TECDOC-540 on Safety Aspect of Nuclear Power Plant Ageing [2]. In the 1980s most people believed that classical maintenance programmes were adequate for dealing with the ageing of NPPs. However, in the 1990s the need for ageing and life management of NPPs became widely recognized.

Programmatic guidelines

The following programmatic guidance reports have been developed using experience of Member States.

• Data Collection and Record Keeping for the Management of Nuclear Power Plant Ageing [3] provides information on the baseline, operating and maintenance data needed and a system for data collection and record keeping.

• Methodology for the Management of Ageing of Nuclear Power Plant Components Important to Safety [4] gives guidance on screening SSCs to make effective use of limited resources and on performing ageing management studies to identify or develop effective ageing management actions for the selected components.

• Implementation and Review of Nuclear Power Plant Ageing Management Programmes [5] provides information on the systematic ageing management process and an organizational model for its implementation.

• Equipment Qualification in Operational Nuclear Power Plants [6] provides the current methods and practices relating to upgrading and preserving equipment qualification in operational NPPs and reviewing the effectiveness of plant equipment qualification programmes.

Component specific guidelines

Based on current experience, practices in Member States and methodology for the management of ageing of NPP components important to safety [4], guidelines to assess and manage ageing of major NPP components important to safety have been developed through technical meetings and coordinated research projects (CRPs). Main objectives for each specific component guideline are:

• To identify significant ageing mechanisms,

• To document the current practices for the assessment and management of ageing,

• To assist Member States in establishing a systematic ageing management programme.

The comprehensive technical guidelines have been issued with common contents as shown below [11-21].

• Component description

• Component design basis

• Potential ageing mechanisms

• Inspection, monitoring and maintenance requirements, techniques and practices

• Methods for the assessment of degradation

• Methods for the mitigation of degradation

• Systematic component specific ageing management programme (AMP)

Ageing Management Review Guidelines [15] is a reference report for Ageing Management Assessment Teams (AMAT) and for utility self-assessments; these reviews can be programmatic or problem oriented. The focus of the project work has progressively shifted from developing awareness, to preparing programmatic, and then component specific guidelines. In
future, the focus will be on providing services to assist Member States in the application of the guidelines. A reduced effort will be maintained to facilitate information exchange through the preparation of additional guidelines and updating of existing guidelines.

Safety Guide on Ageing Management is being developed for NPP and research reactor. This SG (DS-382) will provide guidelines for operators on how to improve the existing AMPs and implement the effective AMPs for new NPPs. Regulators will use it to set up requirements and verify NPP’s compliance with requirements.

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Fig. 2. Structure of IAEA publications related with PLiM and ageing management.