AP1000 Digital Rod Position Indication Detector Malfunction Issues and Analytical Processing Available to Purchase

AP1000 Digital Rod Position Indication (DRPI) detector is used to locate the control rods’ position in the core to within 6 steps. Without rod position information, the plant is not allowed to remain at power. Constant and accurate rod position is necessary due to the importance of control rods and their effect on reactor power control. This paper briefly introduced the function of the AP1000 DRPI detectors and its significance to the plant, and then described the malfunction issues of DRPI detectors discovered at Sanmen Unit 1 during inspection and installation, and potential risks/effect detailed as well as the RCA (Root Cause Analysis) and Remediation /Corrective Actions. Finally, summed up experiences and feedback, provide a reference for the follow-up units and other nuclear power plants.