Laser welding of a sleeve within a tube

A method for welding a sleeve within a tube of a nuclear stem generator, the sleeve having been first expanded into close contact with the tube at a predetermined weld site, the method comprising:

• positioning a high-power laser adjacent a manway of the steam generator;
• inserting a laser beam transmitting means into the steam generator through the manway;
• positioning a weld head apparatus comprising a remote beam receiving means and a welding head having a focusing lens means and a welding mirror means beneath the tube to be welded and axially inserting the welding head to the predetermined weld site;
• aligning the remote beam receiving means with the beam transmitting means for optimum transmission by the transmitting means and optimum reception by the receiving means;
• actuating the high-power laser and directing a high-power laser beam through the beam transmitting means to the beam receiving means and upwardly within the tube to the welding head;
• focusing the laser beam with the focusing lens means;
• reflecting the focused laser beam into contact with the sleeve with the welding mirror means;
• and
• rotating the welding head at a predetermined speed to fuse the interface between the sleeve and tube about the peripherery of the sleeve.

A method for welding a sleeve within a tube of a steam generator, the sleeve having been expanded into close contact with the tube at each end of the sleeve, the method comprising:

• transmitting a high-power laser beam from a high-power laser to a weld head apparatus having a welding head positioned within the sleeve and tube near one end of the sleeve;
• focusing the laser beam with a focusing lens means within the weld head and directing the focused laser beam out of the welding head and into contact with the sleeve with a welding mirror means;
• fusing the sleeve to the tube by rotating the welding head to circumscribe a complete weld path about the inner periphery of the sleeve with the laser beam;
• discontinuing transmission of the laser beam to the weld head apparatus;
• axially indexing the welding head to a position within the sleeve and tube near the other end of the sleeve;
• transmitting a high-power laser beam to the weld head apparatus;
• focusing the laser beam with a focusing lens means within the weld head and directing the focused laser beam out of the welding head and into contact with the sleeve with a welding mirror means;
• fusing the sleeve to the tube by rotating the welding head to circumscribe a complete second weld path about the periphery of the sleeve with the laser beam;
• and
• discontinuing transmission of the laser beam to the weld head apparatus.