Sherlock Project - Investigate to mitigate

To improve the understanding of ageing mechanisms and to support the asset management of steam generators (SGs), EDF in collaboration with the Materials Ageing Institute (MAI) is undertaking a major project to investigate two retired steam generators. The two selected SGs, one from Cruas unit 4 and the other from Paluel unit 2, are recirculating AREVA designs with thermally treated alloy 600 tube bundles and presenting about 30 years of operation. Topics of interest concern wear mechanisms, vibration fatigue, secondary side corrosion of tubes, denting, clogging, fouling, alloy 690 tube plugs, SG internals, tube ends, secondary side chemistry, zinc injection and NDT (non-destructive testing) probes developments by reliability studies. For each topic, the paper will describe the broad guidelines of the destructive examinations program. Most of these examinations will be performed in the new hot laboratory of EDF called LIDEC