January-February 2019 NPJ

Path to Digital Rod Control By Christopher Meier, Westinghouse Electric Company LLC. Christopher Meier Chris Meier is a principal engineer, Rod Control & Position Indication Systems, at Westinghouse where he leads and supports design, documentation and installation of rod control systems, including the Westinghouse Advanced Rod Control Hybrid and Digital Rod Control System. For the latter, he oversaw system installation, startup and testing in Asia. Mr. Meier started working at Westinghouse 12 years ago as a senior engineer in which position he oversaw manufacturing at sub-suppliers and factory acceptance testing, among other duties. Prior to this, Mr. Meier worked at Northrop Grumman Newport News (now Huntington Ingalls Industries). He has received the George Westinghouse Signature Award for Excellence and shares a patent for the Digital Nuclear Control Rod Control System. Mr. Meier earned his Bachelors of Science in Electrical Engineering degree from Pennsylvania State University. Drop-in Replacement for Digitizing Rod Control To help plants simplify the path forward from analog to digital rod control, Westinghouse is introducing a third generation digital rod control system called the Westinghouse Advanced Rod Control Hybrid – or ARCH. Plant owners have expressed that replacing a critical, complex and large system such as rod control presents many challenges if it is to be accomplished within one typical outage. Additionally, performing a full cabinet-for-cabinet replacement is not the most feasible approach due to size constraints and other logistics concerns, and some cabinets have no need of a full replacement of all components. The lack of availability of experienced personnel who can maintain the original analog systems is also an important issue in the industry.` Addressing each of these concerns, W e s t i n g h o u s e designed ARCH to be a drop-in replacement solution for existing W e s t i n g h o u s e Solid State Rod Control Systems and Combustion Engineering Control Element Drive Systems (CEDS), Coil Power Programmer [CPP] and Control Element Drive Mechanism Control Systems [CEDMCS] that offers, among many benefits, lower risk to the outage schedule than implementing a full Digital Rod Control System replacement. This is achieved by using existing architecture, cabinets and system components that do not require replacement where possible, and focusing on replacing the control electronics and other critical components as necessary. The system is modular and allows for a scalable path forward for future system upgrades as financial, lifecycle and upgrade strategies allow. ARCH incorporates more than 20 years of digital rod control experience from the Microprocessor Rod Control System installed in plants during the early 1990s to the new generation systems installed in the AP1000® and APR1400 nuclear power plants. ARCH:  Removes single point vulnerabilities.  Eases Surveillance.  Eases troubleshooting.  Reduces hardware requirements.  Reduces maintenance.  Minimizes outage impact for installation.  Reduces spare parts inventory requirements.  Offers one basic design with common components for Westinghouse and Combustion Engineering systems.  Integrates well with other Ovation™ upgrades, such as the Turbine Control System and Nuclear Steam Supply System. Westinghouse Plant Application While the Westinghouse Solid State Rod Control System has operated reliably for more than 30 years, it lacks certain built-in redundancies and diagnostics capabilities, and obsolescence concerns are increasing, especially for the control electronics. ARCH solves these challenges by leveraging the features and functions of the full Westinghouse Digital Rod Control System while allowing the existing Westinghouse Solid State Rod Control System cabinets, system architecture and power electronics to be retained. At its base installation for Westinghouse plants,ARCHconsists of an electronics control assembly that replaces the existing analog control cards and the phase transformer network, reducing the total card count from 20 cards of seven different types per power cabinet to nine active control cards of three types and one built in backplane extender card, installed 38 NuclearPlantJournal.com Nuclear Plant Journal, January-February 2019