Abstract: This paper briefly introduces the welding joint structures, ageing mechanism and factors of affecting the aging and structure failure, service-induced flaws distribution and characteristics, the challenges and requirements for small branch pipes aging management in PWR nuclear power plants. Then, the following advanced monitoring and inspection technique and its applications were discussed in detail, such as the ultrasonic phased array inspection of small bore pipes butt welds and sockets welds, the high power micro-focus-point CT imaging techniques application in flaw 3D reconstruction and finger-print of qualification testing blocks, pipe vibration measurement with no-contact laser doppler vibrometer, pipe strain and temperature cycle monitoring with optical time domain and frequency reflectometry technique based on Rayleigh scattering principle. Furthermore, the advantages and disadvantages of the above-mentioned techniques and developments were discussed.