A METHOD AND APPARATUS FOR REMOTE WELDING INSIDE A TUBE,IN PARTICULAR IN A STEAM GENERATOR IN A NUCLEAR POWER STATION

摘要

A bush (M) is initially fixed inside a tube (T) which is fixed in a perforated plate (P) of a steam generator in a pressurized water nuclear power station, lining a damaged portion of the tube. A welding light beam is provided by a YAG laser and is conveyed by an optical fiber (F) to an optical cell (30, 37) which focuses the beam on the bush in order to weld it, the cell rotating about the fiber in order to form a circular weld fillet. The fiber is free to slide axially in order to improve focusing which is done to slide axially in order to improve focusing which is done by means of an adjustment beam provided by a hellium-neon laser, the beam running along the fiber in both directions.