Manufacturing method and device of control rods for nuclear reactors

An apparatus for manufacturing a control rod of a nuclear reactor, the control rod comprising a blade including neutron absorbers inserted in a recess portion of a sheath formed by bending, a tie rod for fixing the blade, a handle fixed to the tie rod and an upper end of the blade, and a lower blade fixed to the tie rod and a lower end of the blade,

• said apparatus comprising a welding apparatus for welding the blade to the tie rod, the blade to the handle and the blade to the lower blade,
• said welding apparatus comprising:
• a work head on which an image pickup apparatus is mounted;
• a moving apparatus for moving the work head to a bevel position as designed in each of welding portions;
• an image processing apparatus for processing an image signal picked up by the image pickup means;
• a detecting apparatus for detecting an actual bevel position based on image data processed by the image processing apparatus;
• arithmetic processing apparatuses for comparing the actual bevel position detected by the detecting apparatus with a bevel position as designed, and calculating deviation of the work head from the bevel position;
• a control apparatus for providing the moving apparatus with a control command to move the work head by a distance corresponding to an amount of the deviation of the work head calculated by the arithmetic processing apparatus plus an amount of an offset of the work head and the image pickup apparatus;
• and
• an apparatus for starting welding after completion of movement of the work head.

An apparatus for manufacturing a control rod of a nuclear reactor, the control rod comprising a blade including neutron absorbers and a sheath, a tie rod for fixing the blade, a handle and a lower blade fixed to the tie rod and the blade, said apparatus comprising:

• a work table on which objects to be welded constituting the control rod are set and welding is carried out;
• a laser oscillator for outputting one of a YAG laser beam and a CO2 laser beam;
• a work head comprising an optical system for transmitting the laser beam oscillated by the laser oscillator and converging it to the objects to be welded by a condenser lens;
• an image pickup apparatus, mounted on the work head, for picking up images of a portion near a bevel of the objects to be welded;
• an image processing apparatus for detecting a bevel position from the image picked up by the image pickup apparatus;
• an arithmetic processing apparatus for comparing the bevel position obtained by the image processing apparatus with a bevel position as designed, and calculating deviation therebetween;
• a servo motor for moving one of the work head and the work table by a distance corresponding to an amount of the deviation of the bevel position calculated by the arithmetic processing apparatus plus an amount of an offset of the work head and the image pickup apparatus;
• and
• a control apparatus for driving and controlling the servo motor, said apparatus comprising at least two work heads and two work tables and a movable mirror between the laser oscillator and the work heads.

An apparatus for manufacturing a control rod of a nuclear reactor, the control rod comprising a blade including neutron absorbers and a sheath, a tie rod for fixing the blade, a handle and a lower blade fixed to the tie rod and the blade, said apparatus comprising:

• a work table on which objects to be welded constituting the control rod are set and welding is carried out;
• a TIG welding torch;
• an image pickup apparatus, mounted on the work head, for picking up images of a portion near a bevel of the objects to be welded;
• an image processing apparatus for detecting a bevel position from the image picked up by the image pickup apparatus;
• an arithmetic processing apparatus for comparing the bevel position obtained by the image processing apparatus with a bevel position as designed, and calculating deviation therebetween;
• a servo motor for moving one of the TIG welding torch and the work table by a distance corresponding to an amount of the deviation of the bevel position calculated by the arithmetic processing apparatus plus an amount of an offset of the welding torch and the image pickup apparatus;
• and
• a control apparatus for driving and controlling the servo motor,
• said apparatus comprising at least two TIG welding torches and two work tables, which simultaneously or alternately perform welding.