German nuclear power plants utility ageing management (AM) - current AM activities

Ageing Management (AM) comprises the technological and administrative measures which safeguard the safety requirements of relevant systems and components during the lifetime of a Nuclear Power Plant (NPP). The German utilities understand that the subject AM is covered comprehensively by the entirety of the numerous precaution and maintenance measures and regulations which have been established since the commissioning of the NPP. The long term integrity of safety relevant NPP systems and components is determined by the requirements stated in laws, guidelines and other safety criteria. The implementation of these integrity requirements is based on the existing regulations and standards and the requirements by the responsible authority considering the current 'state of the art' beginning with the plant building and commissioning. Demands for redundant safety and for surveillance measures are also included. Thus, a continuous adjustment is provided by the utilities and submitted to the corresponding safety authority in order to demonstrate an appropriate integrity status of the safety relevant systems. The assignment of such safety requirements to corresponding measures for relevant components is arranged in three groups of high, medium and low safety relevance. The corresponding regulations within these groups are documented in instruction manuals, authority approvals or other plant specific documents governing technical as well as administrative aspects. With respect to the plant specific AM activities, an integrated documentation is provided in a 'Basic Report' which is a comprehensive summarized compilation of all relevant information concerning long term integrity aspects including basic AM-criteria, applied AM-measures and approach procedures. The future AM documentation is performed in periodical 'Recurrent Reports' describing just the 'Delta'-information compared to the 'Basic Report' content. (authors)