Study on energy saving robot used for screw hole cleaning of reactor vessel in nuclear power plant

Abstract Reactor holes can become stuck due to high temperature, high pressure, prolonged bonding, and load changes due to pressure changes in the reactor. To seal pressure in the reactor vessel, the threaded surfaces of the bolt holes shall be cleaned to remove any foreign matter that may be present in the bolt holes. The worker may manually enter the stud hole for the stud hole cleaning, but the worker’s radiation exposure is increased. Robots are an effective way to work in dangerous areas. Therefore, we introduced robots to clean the stud holes. The positioning of mobile robot is generally based on the mileage, but with the increase of the mileage, the position error will accumulate continuously. In order to eliminate the accumulated error and ensure the stability of the drive, a laser sensor and a new control algorithm are adopted. The distance between the robot and the wall is measured by the laser sensor, and the control algorithm is implemented. The value measured by the sensor moves along the desired trajectory. The actuation performance and hole sensing performance of the robot are verified by field application.