The guidelines, which support effective implementation of field programmable gate arrays in both safety and non-safety applications, can provide protection against obsolescence.

Field programmable gate arrays (FPGAs) are increasingly being implemented as an alternative or complement to microprocessor-based systems in certain nuclear plant instrumentation and control (I&C) applications, including safety systems. FPGAs can provide better protection against obsolescence than conventional microprocessor-based systems because FPGA technology does not change as rapidly as microprocessor technology. FPGAs also have the potential to simplify regulatory approval.

To support effective implementation, EPRI has developed guidelines and design criteria for utilities, contractors and suppliers involved in specifying or designing both safety and non-safety FPGA-based I&C solutions for nuclear power plants. The report, Recommended Approaches and Design Criteria for Application of Field Programmable Gate Arrays in Nuclear Power Plant I&C Systems (1022983), discusses how FPGA-based solutions can support diversity and defense-in-depth strategies, and can help provide protection against cyber security threats. The report shares guidance on achieving the benefits of FPGA technology in nuclear plant I&C systems, including the ability to:

• Reduce hardware and logic complexity
• Segregate functions to provide functional independence
• Improve potential for long-term support
• Provide internal design diversity when needed
• Protect system interfaces from adverse interactions.

A key element of the new product is a comprehensive set of guidelines and design criteria applicable to any FPGA-based project. These cover projects of varying size and scope, from component or circuit board level changes up to complete system replacements and designs for new plants. Although an FPGA can provide a final product that is hardware-only, the process used to develop the product involves complex software tools to design and verify the application. Therefore, guidelines are provided on managing the development project, applying a well-defined life cycle and configuration management processes similar to those used for software development.

Criteria and guidelines are included for defining requirements to achieve the needed functionality, dependability and capability for long-term support. The report provides design criteria that address designing for simplicity, fault tolerance and self-monitoring, testability, use of synchronous design principles, use of language and coding rules and other defensive design measures needed depending on the criticality of the application. Guidelines and criteria also are provided for verification and validation, including use of formal verification methods where appropriate, and for evaluation and selection of software tools needed for design and verification.

Finally, to support regulatory approval of FPGA applications, the report reviews U.S. and global standards and provides guidance on important topics that should be addressed in developing a safety justification.

For more information, contact Joe Naser at 650.855.2107 or jnaser@epri.com.