Study On Fault Diagnosis Of Rod Control And Position Measurement Device Of Nuclear Power Station

The control rods are used to implement quick regulation of the reactor power and emergent shutdown of the reactor in pressurized water nuclear power station. These rods work in the condition where the temperature and pressure is quite high,and the movement control and position measurement of the rods are one of the important techniques of the nuclear power station.The fault diagnosis of the rod control and rod position measurement system are important and this dissertation make research on this subject.The dissertation analyzes the fault of the rod control and rod position measurement system with the fault tree analysis theory, and the fault tree of rod control system and rod position system are established respectively with the fault alarm as the top event.The dissertation analyzes the fault model of CRDM, and the diagnosis strategy of CRDM fault is proposed based on the characteristics of the electric current waveform. Three new concepts, such as measurement segment of rod position, are proposed in this dissertation, and the origin and constitution of the measue error are analyzed. On this basis,a new method of fault diagnosis of rod position measurement device which have high sensitivity, less than 2 steps in the boundary dot.The software of fault diagnosis of rod control and rod position system is developed. The software consists of PLC software and monitoring software of rod control logic cabinet, PLC software and monitoring software of rod position processing cabinet, PLC software of electric power cabinet, and fault diagnosis data managing software.