Repair welding method and apparatus in reactor pressure vessel

摘要

PURPOSE:To reduce the exposure by forming a repair welding machine by a water-proof structure, performing an installation and carrying-in and carrying-out of a welding machine in a state that water is put into the vessel, placing the upper cover on the vessel and shielding it after installing the welding machine, bringing it to draining and executing the welding by a remote control. CONSTITUTION:At the time of installing, and carrying in and out a welding machine, a torch 11 and a welding wire 12, etc., are stored in the lower watertight case 8 in a dry state, and transferred in the water. During this time, a worker transfers and installs the device by a remote control from the upper part of the vessel. After the welding machine is installed in an appropriate position, the upper cover is placed on the vessel, and draining of the vessel is executed. Subsequently, the torch 11 contained in the case 8 is allowed to descend to a prescribed position by a torch ascending/descending motor 14. Thereafter, an opening/closing shutter 16 of the case 8 is opened by interlocking with the motor 14. Also, the torch 11 is inclined so as to become a condition being suitable for welding in accordance with an inclination angle of the lower mirror by a torch inclining motor and welding is performed. After builtup welding is ended, the torch 11 is contained into the case 8 again, the shutter 16 is closed, and in a state that a dry state is held, water is put into the vessel, and the welding machine is carried out to the upper part of the vessel.