| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a reforming method for pipe inner surface capable of easily and surely reforming the pipe inner surface of especially a small diameter pipe so as to improve resistivity for stress corrosion cracking. SOLUTION: For example, on the inner surface of a core instrumentation tube 4 being a small diameter pipe formed with nickel base alloy (600 alloy) fixed by welding 3 to a reactor vessel, a ring shape recess 4a is formed from the opening end. A cylindrical sleeve 11 formed with other nickel base alloy (690 alloy) having larger resistivity to stress corrosion cracking than the material of the core instrumentation tube 4 is inserted from the open end of the core instrumentation tube 4 to fit in the part where residual stress due to welding is generated. Then, in the inner space of the sleeve 11, a laser welding tool 12 is inserted and rotated around the center axis of the core instrumentation tube 4 to cast laser light 13 from the inner surface side of the sleeve so that the sleeve 11 is clad on the inner surface of the core instrumentation tube 4.</p> |
