Manufacturing method and device of control rods for nuclear reactors

A method for manufacturing a control rod of a nuclear reactor, the control rod comprising a blade including neutron absorbers and sheathes, a tie rod to be fixed to the blade at a first groove, a handle to be fixed to the blade at a second groove and a lower-blade to be fixed to the blade at a third groove, said method comprising:

• cutting weep holes for water to cool the neutron absorbers in the sheath and cutting a periphery of the sheath;
• bending the sheath cut in the cutting step to a C-shape;
• inserting the neutron absorbers in a bent portion of the sheath formed by bending in the bending step;
• welding the blade to the tie rod so that the first groove is welded reliably to secure a penetration bead on a rear surface of the sheath by irradiating a laser beam on a first portion deviated from the first groove within a range of 2 mm, the blade to the handle so that the second groove is welded reliably to secure a penetration bead on the rear surface of the sheath by irradiating a laser beam on a second portion deviated from the second groove within a range of 2 mm, and the blade to the lower-blade so that the third groove is welded reliably to secure a penetration bead on the rear surface of the sheath by irradiating a laser beam on a third portion deviated from the third groove within a range of 2 mm;
• and
• finishing portions welded in the welding step.