headpiece with ineinanderschiebbarer style building for kernbrennelement

摘要

The invention concerns an expandable top nozzle subassembly (12) for a nuclear fuel assembly, including a lower or adapter plate (26), a top or hold-down plate (30), and hold-down springs (60) disposed between the top and adapter plates to transmit to the adapter plate hold-down forces applied to the top plate. The top plate (30) is part of an upper structure (24) including a sidewall enclosure (32) which is integrally connected to and depends from the outer peripheral edge (30A) of the top plate (30), the adapter plate (26) being captively disposed within the sidewall enclosure in a manner permitting relative movement between it and the upper structure (24). This arrangement permits the adapter plate (30) to be mounted higher on the control-rod guide thimbles (16), thereby allowing for more fuel-rod growth, and still leaves enough room between the top and adapter plates for handling equipment to be engaged.