Advanced Techniques for On-Line Condition Monitoring and Diagnostics of Digital Rod Position Indication Systems for Existing and Next Generation Nuclear Power Plants

The designs of many existing nuclear power reactors incorporate a digital rod position indication system to monitor the positions of the control and shutdown rods within the reactor. These digital rod position indication systems have been in service for over 30 years in nuclear power stations worldwide. In recent years, however, aging and obsolescence issues have led to an increase in problems with the digital rod position indication systems including analog card failures and coil cable connection problems that, in some cases, may result in unplanned reactor trips. These problems, along with plans for plant life extension, have prompted the nuclear industry to actively seek viable options to monitor the health and accuracy of these digital rod position indication systems in order to ensure reliable plant operations for decades to come. The existing plants will be facing the end of qualified life for several components of the existing digital rod position indication systems during the next decade and are actively seeking replacement options at this time. As such, the objective of this project is to conduct a research and development effort to design, implement and demonstrate an advanced digital rod position indication diagnostic system for existing and new nuclear power reactors. In the Phase I project, the proposing firm demonstrated the feasibility of developing a digital rod position indication monitoring system from commercial parts that not only monitors for system diagnostics, but also provides additional capabilities such as higher resolution rod position indication than is currently available as well as automatic rod drop times. The approach in Phase II is to build on the success of Phase I to construct a prototype digital rod position indication diagnostic system and implement it in an existing nuclear power reactor. The prototype digital rod position indication diagnostic system constructed in the Phase II project will be used as the basis for the design of a digital rod position indication diagnostic system for next generation reactors. Commercial applications and benefits: As plants focus on replacing obsolete digital rod position indication system components, this proposal offers a commercial system that will also provide enhanced diagnostic capabilities if carried into Phase II and commercialized in Phase III.