Vol.1 No.1 ← GA 5 - AP 6 - 7 - NT 7 - 7(1) - 7(2) - 8 - 9 → Vol.1No.3 | ||||
Vol.1, No.2, NT7(2)
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WATER JET PEENING AS RESIDUAL STRESS IMPROVEMENT METHOD FOR ALLOY 600 PWSCC MITIGATION |
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MITSUBISHI HEAVY INDUSTRIES, LTD. | ||||
KEYWORDS: |
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1. Technical summary | ||||
Classification (I: Inspection, II: Repair, III: Replacement, IV: Preventive Maintenance, V: Others) | ||||
The improvement of surface residual stress is effective in prevention of stress corrosion cracking (SCC) occurring by tensile residual stress. Water jet peening (WJP) generates the compressive residual stress on the surface of the material by the extremely high impulse pressure caused by the collapse of cavitation bubbles when high speed water jet is discharged in the water. | ||||
2. Scope | ||||
(1) Components:Reactor vessel (RV) of PWR
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Fig. 1 WJP objects in reactor vessel of PWR plant (example) | ||||
3. Features | ||||
(1) WJP improves stress on a material surface in a wide and deep area with only one or a few travel path.
Fig.2 WJP situations for PWR objects
(c) Residual stress of nozzle inner surface
Fig.3 Effect | ||||
4. Examples of Application | ||||
Several parts of PWR plants as below,
(1) Outlet/Inlet Nozzle safe-end of RV (more than 10 plants) (2) Safety Injection Nozzle safe-end of RV (3) RV Bottom Mounted Instrument (BMI) outer/inner surface and J-weld (more than 10 plants)
Fig. 4 Application of WJP equipments
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Fig. 5 Demonstration of WJP for BMI J-weld |
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5. Reference | ||||
RELIABILITY OF WATER JET PEENING AS RESIDUAL STRESS IMPROVEMENT METHOD FOR ALLOY 600 PWSCC MITIGATION ICONE16-48375 (2008) |
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6. Contact | ||||
Japan Society of Maintenology (ejam@jsm.or.jp) | ||||