Abstract: BOSS weld is the joint weld between pipeline and branch pipe base.The branching and diameter change at BOSS weld position in radioactive system pipeline of nuclear power plant will likely result in the deposition of high radioactive particles.In addition,due to the limited maintenance space,its related operations have a high radiation risk.Based on the main steps of BOSS weld maintenance,this paper analyzed the external radiation and radioactive contamination risks during the operation process,introduced practical and feasible measures for radiation protection,as well as maintenance experience feedback and good practice during the process,which will provide reference for radiation protection control of BOSS weld maintenance of M310 nuclear unit.

Key words: BOSS weld, radiation risk, radiation protection control