TOOL FOR REMOVING AND REPLACING A TOP NOZZLE LOCKING TUBE OF NUCLEAR FUEL ASSEMBLY

摘要

A hand held tool (48) for removing a hollow locking tube (56) from a locking position in the upper end portion of a guide thimble includes an elongated hollow tubular assembly (72) having a lower end portion (72B) insertable in the locking tube (56) and an actuator assembly (74) mounted through the tubular assembly (72) for axial movement therealong and having a lower end portion (74B) for actuating a set of lifting members (90) of the lower end portion of the tubular assembly to extend and retract their catch elements (90C) through and from apertures (100) in the tubular assembly for engaging with and disengaging from a lower edge (56B) of the locking tube (56). The lower end portion (72B) of the tubular assembly (72) includes a guide member composed of a hollow tubular element (94) and a guide element (96) interfitted with an open end (94A) of the tubular element (94) and having a body portion (96) projecting therefrom. The tubular element (94) has the apertures (100) through which the catch elements (90C) on the lifting members (90) can be extended to engage the lower edge (56B) of the locking tube (56). The end of the tubular element (94) and the body portion (96) of the guide element (96) have substantially the same outside diameter so as to provide a continuous smooth transition from the tubular element end to the guide element body portion for facilitating insertion of the guide and tubular elements of the guide member into the hollow locking tube without catching on an upper edge thereof at the transition of the guide member.