REVIEW OF THE BELGIAN EXPERIENCE OF REACTOR CORE INTERNAL COMPONENTS

In Belgium, some typical reactor core internal components have experienced various types of damage, which are attributed to either intergranular stress corrosion cracking (IGSCC) or to flow-induced vibrations. This paper reviews the degradation processes affecting: - control rod guide tube support pins, - rod cluster control assembly rodlets - in-core instrumentation thimbles. The investigations performed are summarized, as well as the corrective actions taken. Finally, potential safety concerns are identified.