Underwater laser welding repair method and laser welding equipment for jet pump measuring pipe

摘要

PPROBLEM TO BE SOLVED: To carry out repair work of a jet pump measuring piping in a nuclear reactor at a low cost, in a short period and at many plants. PSOLUTION: The underwater welding repair method for the jet pump measuring piping 3 attached to the jet pump arranged in the reactor water inside the nuclear reactor comprises the following processes. The process to remove a part of the piping including a damaged portion, cutting by electrical discharge machining at the both sides in the axial direction of a fractured portion and damaged portion such as cracking in the jet pump measuring piping 3. The process to have the both cut edge portions of the jet pump measuring piping 3 insert respectively into a welding sleeve 8. The process to laser-weld the welding sleeve 8 circumferentially with the inserted part of the jet pump measuring piping by irradiating laser beam circumferentially, while supplying shield gas sg to the outer periphery of the welding sleeve 8 corresponding to the inserted position and displacing the reactor water. PCOPYRIGHT: (C)2004,JPO&NCIPI