Abstract: The colletive dose distribution of general service personnel in different positions during the first overhaul of Unit1 in some NPP is presented. The sources and causes of dose are analyzed. Some improvement measures for optimization are proposed correspondingly, which's then been applied to the first overhaul of Unit 2. The implementation of these measures has been verified by overhaul personnel dose comparison of both units. And thegoal of reducing personnel dose is ultimately achieved.

Key words: Overhaul, Radiation dose, General service