The nuclear reactor pressure vessel（RPV）is the only non-replaceable core equipment in the nuclear power plant

which can withstand high temperature

high pressure and strong radiation. It has high design standards and specifications

difficult manufacturing process and strict quality control requirements.And the key welding technologies directly affect the quality and manufacturing schedule of the equipment

which is not only closely related to the economic benefits of nuclear power plant construction and operation

but also is the cornerstone of nuclear safety and even influences national security. In this article

by analyzing the characteristics of key welding technology and the typical quality problems of HPR1000 RPV

and by the research andoptimization and engineering practice of welding technology

the welding quality of HPR1000 RPV is significantly improved

meanwhile the time limit for a project is greatly shorten and the engineering cost is saved. This provides a valuable technical accumulation and engineering experience for subsequent manufacturing of HPR1000 RPV.