Rod Control System On-Line Condition Monitoring and Advanced Diagnostics for Existing and Next Generation Nuclear Power Plants

A Light Water Reactor (LWR) is equipped with control and shutdown rods that are inserted into and withdrawn from the core to control the power level in the reactor. The positioning of the control and shutdown rods is performed via the plants rod control system, which in a typical Pressurized Water Reactor (PWR) includes a number of subsystems and components such as the Control Rod Drive Mechanism (CRDM), power regulation circuitry, and control logic electronics. These rod control systems have provided safe and reliable service in nuclear power stations worldwide for over 30 years; however, aging and obsolescence issues have led to problems with the systems including regulation card, firing card, and power supply failures as well as cable connection problems that have resulted in unplanned outages. These issues, along with plans for plant life extension, have prompted the industry to actively seek viable options to monitor the health of these rod control systems in order to ensure reliable plant operation for decades to come. In addition to obsolescence concerns, the lack of diagnostic capabilities in the rod control system is a significant problem. Moreover, reactor operators typically clear alarms before engineering personnel can be informed, which eliminate the diagnostic information from the system. This leaves the systems engineer with little direction to begin troubleshooting activities. As such, CRDM and rod control component failures can occur without warning, which can lead to increased costs for the plant, especially if the cause of the failure is not readily apparent and/or replacement parts cannot be requisitioned in a timely manner. As such, the objective of this project is to conduct a research and development effort to design, implement and demonstrate an on-line rod control condition monitoring and diagnostic system for existing and new nuclear power reactors.