Nuclear fuel assembly top nozzle with improved peripheral hold- down assembly

摘要

A fuel assembly has a top nozzle which includes a lower adapter plate and a plurality of guide structures thereon. The lower adapter plate has a peripheral edge. The guide structures are attached to and extend upwardly from the lower adapter plate at locations spaced inwardly from the peripheral edge of the lower adapter plate so as to separate the lower adapter plate into an interior portion extending between interior sides of the guide structures and mountable to the guide thimbles and a peripheral portion extending about exterior sides of the guide structures. The guide structures define a plurality of vertical guide slots. The top nozzle also includes a peripheral hold-down assembly disposed along the peripheral portion of the lower adapter plate about the exterior sides of the guide structures and having a plurality of guide tabs movably coupled to the guide slots of the guide structures for permitting vertical movement of the hold-down assembly relative to the lower adapter plate and guide structures in providing a downward biasing force against the peripheral portion of the lower adapter plate of the top nozzle. The peripheral hold-down assembly includes a peripheral arrangement of leaf springs and an annular upper retainer member overlying the peripheral portion of the lower adapter plate and engaging the peripheral arrangement of leaf springs.