| 摘要 |
<p>PROBLEM TO BE SOLVED: To simplify an installation and an equipment, to shorten a working period, to suppress the radiation exposure of a working people and to improve cutting precision, by approaching a cutting means to a material to be cut and transmitting laser beam through an optical fiber and assist gas through a gas supply tube thereby improving applicability to a narrow part. SOLUTION: At the state where water is charged in a nuclear reactor pressure container 1, a cutting means 4, to which an optical fiber 1 and a gas supply tube 21 are connected, is hung by a crane C and a wire rope R and then hung down into a stored water. At the state where an irradiation part and a gas injection port are approached to the inner face of an object to be cut, a laser beam generating means 10 and an assist gas supply means 20 are operated. By supplying the assist gas through the assist gas supply tube 21, the assist gas is injected from the gas injection port to form assist gas atmosphere around the irradiation part, by transmitting laser beam from the optical fiber 11, the material to be cut is irradiated with the laser beam to be heated/melted.</p> |
