CORE CONSTITUTING ELEMENT AND CORE CONSTRUCTION OF FAST BREEDER AND FAST BREEDER

摘要

PURPOSE:To improve the unloadability of the core constituting element by installing a buffer member which is smaller in the rigidity in the direction perpendicular to the axial direction of an entrance nozzle than a core supporting plate on the surface of the entrance nozzle. CONSTITUTION:The core constituting element (fuel assembly) 1 is supported in a cantilever state by inserting the entrance nozzle 15 in the hole of the core supporting plate 22 of a core vessel or a connecting pipe provided to the supporting plate 22. The buffer member 3 having the rigidity in the perpendicular direction of the nozzle 15 smaller than the rigidity in the perpendicular direction of the supporting plate 22 or the connecting pipe is provided on the surface of the nozzle 15. The curving quantity which ought to be absorbed intrinsically by the deformation of the adjacent core constituting element 2 or the used constituting element 1 to be unloaded is absorbed by the easy deformation of the member 3 having the small rigidity in such a manner. The loads acting on the used core constituting elements 1 to be unloaded to the used core constituting element holding space and the constituting elements are, therefore, decreased and the friction force is lessened. As a result, the unloadability is improved.