State of the art of the conceptual designs for ASTRID control and shutdown rods

I Guénot-Delahaie (1) , D Lorenzo (1) , B Valentin (1) , J.-M Escleine (1) , T Helfer (1)

1 CEA - Commissariat à l'énergie atomique et aux énergies alternatives

A critical look at the conceptual designs of control and shutdown rods and absorber elements, along with the lessons learnt from the operation of French fast reactors (Phénix and Super-Phénix especially) and the associated irradiation tests, has yielded improved and even innovative absorber assembly design concepts which are presented in this paper. To comply with the GEN IV objectives set for the 600 MWe Advanced Sodium Technological Reactor for Industrial Demonstration (ASTRID), these design concepts have been researched with a view to improved economy/sustainability and enhanced safety. The two main measures undertaken to achieve economy, among many others, have been to reduce the absorber subassembly dimensions and boron carbide enrichment, as well as to extend the residence time. To achieve enhanced safety, measures could include improved components and/or structural materials and guidance surface coatings/hard-facings in active shutdown systems. As part of these measures, a new kind of absorber assembly has also been designed – called SEPIA 1 – pertaining to safety devices for the passive insertion of negative reactivity in the core. Preliminary thermal-hydraulic and structural mechanical analyses have been carried out with the CADET and LICOS project codes to show their feasibility. Further detailed analyses need to be carried out to achieve optimum dimensions that comply with the RAMSES II design rules. The paper discusses the basis of the conceptual designs, giving due consideration to emerging design concepts, analysis backups and further R&D required for design qualification.

Domaines: Matériaux et structures en mécanique [physics.class-ph]; Matériaux et structures en mécanique [physics.class-ph]

I Guénot-Delahaie, D Lorenzo, B Valentin, J.-M Escleine, T Helfer. State of the art of the conceptual designs for ASTRID control and shutdown rods. International conference on Fast Reactors and related fuel cycles, FR13, 2013, Paris, France. ⟨hal-01860418⟩