Development and Application of Control Rod Drive Mechanism Latch Assembly Inspection Equipment

The function of control rod drive mechanism is to lift and lower control rods to control the nuclear plant power and shutdown quickly and safely in emergency. To meet an EPR nuclear power plant’s structural integrity verification requirement of latch pin washers in situ, which is covered by other components in control rod drive mechanism latch assemblies, a radiographic inspection equipment based on a foldable 5-joint robotic arm is proposed in this paper, making it possible to inspect safely, efficiently, and accurately in the limited, staff inaccessible and radioactive environment. The equipment has been proved by field application, and target inspection structures were visible clearly in obtained γ-ray films.