| 摘要 |
PROBLEM TO BE SOLVED: To provide a water jet peening method in which the resonance of structures in a reactor pressure vessel other than objects to be subjected to water jet peening are avoidable.SOLUTION: A jet 8 containing cavitation air bubbles is injected from an injection nozzle 4, and water jet peening is performed on the inner surface of a reactor pressure vessel 1. The pressure pulsation 20 resulted from the jet 8 reaches a reactor core internal structure 2. The pressure variation due to the pressure pulsation 20 is detected with a pressure sensor 15 near the reactor core internal structure 2 to be input into an arithmetic unit 17. The arithmetic unit 17 separates the oscillatory waveform of the natural frequency fcomponent of the reactor core internal structure 2 from the pressure variation. A control device 18 controls an electromagnetic valve 12 on the basis of the oscillatory waveform, and injects water stream with the pressure pulsation 22 having the amplitude and frequency comparable in opposite phase to the oscillatory waveform from a jet orifice of an enlarged part 24. The pressure pulsation 20 is canceled with the pressure pulsation 22, turning into the pressure pulsation 23 with small amplitude. |
