ON-LINE MONITORING AND DIAGNOSTICS FOR ROD CONTROL SYSTEMS IN NUCLEAR POWER PLANTS

摘要

Existing pressurized water reactors (PWRs) employ a rod control system to move the control and shutdown rods into and out of the reactor. Component aging, obsolescence, and environmental stresses have led to an increase in rod control system problems, including electronic card failures; logic errors; timing, latching and rod movement problems; and control rod drive mechanism (CRDM) coil and cable degradation. The existing plant equipment and maintenance activities provide only limited monitoring and diagnostic information on the condition and health of rod control system components. This paper describes research and development (R&D) performed to develop a Rod Control Diagnostic System (RCDS) for on-line condition monitoring of the rod control system to warn plant engineers of developing problems. The R&D also focuses on improving maintenance activities through the automation of plant surveillances such as CRDM timing and sequencing, coil and cable impedance calculations, and dc hold testing. The combination of optimized testing and online monitoring will improve rod control system performance and provide information that supports extended plant operating life and improved plant reliability for the nuclear power industry.