This document is Part 8 of T/CNEA103 "Non-destructive testing of pressurized water reactor pressure components". This document consists of 7 chapters in total, of which Chapters 1-3 are normative provisions, and Chapters 4-7 are Part 8 of non-destructive testing of pressurized water reactor pressure components: main contents of leak detection. The main contents include: general requirements, equipment and equipment, testing methods and techniques, and testing reports.