Robot System and Fastening Force Control for Sealing Blocking Plates of Steam Generator

During the nuclear power plant maintenance period, the primary side manhole of the steam generator will be opened. In order to prevent water in the primary circuit of the reactor from flowing into the water chamber, it's necessary to block the steam generator primary side cold-hot end and primary circuit pipe connection. This maintenance operation has a high dose of radioactivity and is not suitable for human operation. The paper introduces a blocking plate manipulation robot for this environment. The mechanical structure was designed in detail, and a positioning method based on image recognition was proposed. The control strategy based on the position and current was proposed for the bolt fastening mechanism. Finally, based on the prototype, the absolute positioning accuracy experiment was conducted, and the results were processed and analyzed.