Periodic safety reviews of nuclear power plants

Operational nuclear power plants (NPPs) are generally subject to routine reviews of plant operation and special safety reviews following operational events. In addition, many Member States of the International Atomic Energy Agency (IAEA) have initiated systematic safety reassessment, termed periodic safety review (PSR), to assess the cumulative effects of plant ageing and plant modifications, operating experience, technical developments, site specific, organizational and human aspects. These reviews include assessments of plant design and operation against current safety standards and practices. PSRs are considered an effective way of obtaining an overall view of actual plant safety, to determine reasonable and practical modifications that should be made in order to maintain a high level of safety throughout the plant's operating lifetime. PSRs can be used as a means to identify time limiting features of the plant. The trend is to use PSR as a condition for deciding whether to continue operation of the plant beyond the originally established design lifetime and for assessing the status of the plant for long term operation. To assist Member States in the implementation of PSR, the IAEA develops safety standards, technical documents and provides different services: training courses, workshops, technical meetings and safety review missions for the independent assessment of the PSR at NPPs, including the requirements for PSR, the review process and the PSR final reports. This paper describes the PSR's objectives, scopes, methods and the relationship of PSR with other plant safety related activities and recent experiences of Member States in implementation of PSRs at NPPs. (author)