Experience feedback on loose part monitoring in France's 54 PWRs Particular cases in the secondary of a SG and in the vessel

Monitoring of loose parts in the extended primary cooling system (extended to the secondary side of steam generators) in nuclear power plants is the central objective of the systems established by EDF. Acoustic monitoring of the extended primary cooling system forms a secondary objective, with a view to improve knowledge of the physical phenomena involved and develop monitoring system features. The general organization of loose part monitoring system in France is described, encompassing the sensors installed on the extended primary cooling system, the installed systems themselves, and the expertise station. This is followed by a summary of the experience feedback from all cases detected since initial commissioning in 1978. Finally, two particularly interesting cases are described: a loose part in the secondary side of a steam generator, and impacts on the vessel bottom head for the Bugey-5 reactor. (author)