This paper briefly introduces the weld cladding structure, its common defects during the manufacture and operation stage and its application in pressurized water reactor nuclear power plants. Some ultrasonic testing codes or standards for nuclear power plant pressure vessel or piping, such as ASME BPVC volume V & III & XI, Germany KTA 3201.3 and 3201.4 code, France RCC-M and RSE-M code, and Russia code of light water nuclear power plants were discussed. The difference of those codes and some feed backs have been analyzed and discussed. Furthermore, these works really benefit the compiling of NB/T 20003.2-2010, Non-destructive Testing for Mechanical Components in Nuclear Island of Nuclear Power Plants-Part 2: Ultrasonic Testing, as China building more and more nuclear power plants. It was concluded that we shall pay more attention to the inspection of cladding, not only at manufacture stage but in operation outage stage. One of important work is periodically updating the inspection standard revision. It was believed that improving the cladding defects inspection reliability and effectiveness is very important to the safety of nuclear power plants operation in China and in the world.

This paper briefly introduces the history, development, aims and roles, state of the art of Inspection Qualification in nuclear power industry in developed countries, such as US and UK. Then, the author reviewed the related works in China in past years and the state of art, the challenges and reflections of building China inspection qualification system. Furthermore, based on the actual situation in China, combined with the advantages and disadvantages of European Inspection Qualification system and ASME Performance Demonstration method, the author put forward some suggestions on organization, system and related technical basis to promote the establishment and development of inspection qualification system in China. It was obvious that the inspection qualifications have to be taken before nuclear power plant pre-service inspection or in-service inspection. The inspection qualification system shall be developed as soon as possible and it will improve nuclear power plants safety operation in China.

Dissimilar Metal Welds have been widely used at safe-related pressure vessels and piping in Nuclear Power Plants. Some industry codes have been developed for nuclear power plants, such as ASME BPVC volume III & XI, Germany KTA 3201.3 and 3201.4 code and Russia code of light water nuclear power plants. The difference of those codes and some industry feed backs and some experiment results have been briefly introduced and discussed. Furthermore, the inspection qualification or performance demonstration, one of new requirements of some codes, especially for pre-service and inservice inspection of nuclear power plants, really promote continual improvements of DMWs UT both on detection rate and sizing accuracy. Additional, these works really benefit the revision of EJ/T 1039-1996, Non-destructive testing for mechanical components in nuclear island of nuclear power plants, as china building more and more nuclear power plants.