Structural Integrity Analysis of Nuclear Power Plant Pressure Vessel Penetration Nozzle Repaired
Abstract: Many NPP pressure vessel head nozzles were manufactured of Alloy 600. Since Alloy 600 is sus-ceptible to PWSCC, the degradation mechanism has been observed in these nozzles. The industry has used several methods to mitigate PWSCC, including replacement of nozzles fabricated of Alloy 690. After the replacement of the nozzle, the structural integrity analysis of new nozzle and welds should be performed to ensure the pressure boundary compliance with the original design re-quirement. The PWR pressurizer top head instrument nozzle is evaluated. Thermal stress of the transients was obtained from 3D FEM analysis and residual stress of J-groove weld was obtained from 2D FEM analysis. Stress intensities and residual stress were conservatively determined and used for the ASME Code, stress intensity analysis, fatigue crack growth analysis and fracture me-chanics analysis. All of the analysis showed that the repaired nozzle satisfies the ASME Code design requirement.
文章引用: 马琳伟 , 何家胜 , 舒安庆 , 郑小涛 , 徐建民 (2017) 核电厂稳压器贯穿接管的修复和结构完整性评估。 核科学与技术， 5， 36-48. doi: 10.12677/NST.2017.51005
 US.NRC. (2005) U.S. Plant Experience with Alloy 600 Cracking and Boric Acid Corrosion of Light-Water Reactor Pressure Vessel Materials. USNRC Report, NUREG 1823. US:USNRC.
 Sun, H.T., Shen, C.Y., Gao, C., Wang, C., Ling, L.G. and Jia, P.P. (2015) The Application of Weld Overlay in the Maintenance of Nuclear Equipment. Welding & Joining, 94, 53-56.
 US.NRC. (1989) Residual Life Assessment of Major Light Water Reactor Components. US.NRC Report, NUREG/CR 4731. US:USNRC.