- Top nozzle hold-down spring unit having improved on-off characteristics and a top nozzle assembly of a nuclear fuel assembly having the same

摘要

The present invention relates to a hold-down spring unit for a top fixture having improved on-off characteristics, which generates hold-down force required at accurate on-off points, and a top fixture for a nuclear fuel assembly having the same. The hold-down spring unit according to an embodiment of the present invention comprises: a first leaf spring (110) having one end fixed to a spring clamp (21) and the other end provided with a first rod portion (111) downwardly bent; at least one second leaf spring (120) having one end overlapping the first leaf spring (110) to be fixed to the spring clamp (21), and the other end provided with a rod insertion hole (121) into which the first rod portion (111) is inserted; and a third leaf spring (130) having one end overlapping the second leaf spring (120) to be fixed to the spring clamp (21), the other end provided with a second rod portion insertion hole (131) into which the first rod portion (111) is inserted, and with a second rod portion (132) which is downwardly bent and is shorter than the first rod portion (111). The second and third leaf springs (120, 130) have a long through hole or recess formed in any one of plate-shaped surfaces facing each other and the other surface can be inserted into the through hole or recess.