TOP NOZZLE ASSEMBLY WITH IMPROVED PRESSURE DROP PERFORMANCE

摘要

The present invention relates to an upper fixation body for a nuclear fuel assembly capable of securing lots of flow path holes to improve pressure drop of cooling water while including an elastic support unit for elastically supporting the upper fixation body by the multi-phase stiffness. The upper fixation body (100) which includes a plurality of flow paths (101) formed therein to fix the upper end of the nuclear fuel assembly comprises an upper nozzle part (110) which has a plurality of first assembly holes formed to be penetrated therein; a lower nozzle part (120) which has a plurality of second assembly holes formed to be penetrated therein and are arranged to be aligned with the upper nozzle part (110); an upper tube (130) and a lower tube (140) which have the hollow shape, are respectively inserted into the first and second assembly holes and are assembled to be slidably fitted to each other; and an elastic support part (151, 152, 153) which is inserted into the upper tube (130) and the lower tube (140) to elastically support the upper nozzle part (110) and the lower nozzle part (120), thereby easily securing the flow path hole to minimize the pressure drop of the upper fixation body and improving the structural safety of the nuclear fuel assembly by elastically supporting the upper fixation body by the multi-phase stiffness according to the pressure section.