WATERJET PEENING APPARATUS AND WATERJET PEENING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a waterjet peening method and a waterjet peening apparatus capable of making a bubble jet device simpler, obtaining a residual stress improvement effect substantially equivalent to that of a conventional technique, and mitigating the damage risk of structures that are arranged around a jet nozzle from which a water jet flow is jetted out and that are not subjected to water jet peening.;SOLUTION: A WJP apparatus 5 comprising a nozzle moving device 3 to which a jet nozzle 1 and a bubble jet pipe 4 are attached, is disposed in a downcomer filled with coolant 18 between a nuclear reactor vessel and a reactor core shroud 15. The bubble jet pipe 4 is disposed below the jet nozzle 1, and a length between central axes of the jet nozzle 1 and the bubble jet pipe 4 is set in a range from Lmax/3 to Lmax/2 in a horizontal direction. Lmax denotes a jet length at which an exciting force F due to a shock wave is equal to a maximum force.;COPYRIGHT: (C)2015,JPO&INPIT