Implementation of remotely operated vehicle for direct inspection of reactor pressure vessel and other water-filled infrastructure

To reduce the irradiation exposure time of inspection personnel inspecting the reactor pressure vessel and other water-filled infrastructure during overhaul period, a remotely operated vehicle (ROV) is developed to help monitor the underwater environment and salvage small parts like bolts and nuts in the reactor pool and other water-filled infrastructure of the nuclear power plants. It is designed to be compact, light and radiation resistant. The depth control strategy based on fuzzy proportion integration differentiation is proposed for the ROV to suspend at any depth of the reactor pool. And the integrated navigation algorithm based on the Kalman filter fuses data from sensors, including sonar, depth gauge, three-axis accelerometer, three-axis gyroscope and three-axis magnetometer. Radiation testing has been conducted to verify ROV's ability to work in the reactor pool and other water-filled infrastructure under the environment of high irradiation. Eventually, field experiment was conducted in the reactor simulation pool of the Daya Bay Nuclear Power Plant, and the result verifies the effectiveness of the depth control algorithm, the integrated navigation algorithm and also the leak tightness of the ROV.