Suggestion on Improving Small Branch BOSS Joints Welding Quality

Abstract

Due to the structural constraints, mandatory volumetric examination is not implemented on small branch BOSS joints of nuclear power plant, which leads to internal defects cannot be detected thoroughly, causing potential risk to the safe and stable operation. Key factors affecting the welding quality of small branch BOSS joints are systematically analyzed in this paper. Besides, practical suggestions are provided on the operating level to improve the welding quality, including groove design, welding process, welder qualification and nondestructive examination. On this basis, further improvement suggestions are proposed to revise the codes and regulatory guides.