Automation levels for nuclear reactor operations: A revised perspective

Abstract

This work serves to propose updated levels of automation for nuclear reactor operations, as a result of considering long-term economic and commercial ambitions of the advanced reactor developer community. As in other fields such as road-going vehicles and aviation, reactor technologies can benefit from modern automation through the resulting reduction in operations and maintenance costs, while still maintaining the current industry standards regarding safety, resilience, reliability, overall performance, and the capacity for root-cause analysis. The current guidelines on automation levels, as published by the U.S. Nuclear Regulatory Commission in Section 9 of NUREG-0700, reflect outdated design principles that implicitly limit the potential of automation innovation for reactor operations, particularly in regard to advanced reactors intended to operate in remote locations or be used for off-grid applications. Motivated by the operational paradigms anticipated for future reactor designs, we propose a six-level approach that aligns with contemporary automation concepts as well as automation level definitions from other non-nuclear safety–critical industries. These levels build upon the current guidelines in order to enable next-generation nuclear reactor technologies to become increasingly economically competitive and commercially viable relative to competing power generation sources. Using a hypothetical heat removal reactor transient, we provide examples of how the human–machine interactions change at each level of automation, ranging from traditional operator control (Level 0) to operator-free unattended operations (Level 5)—the latter being one of the key attributes proposed at the Fission Battery Initiative led by Idaho National Laboratory. Finally, we critically examine the identified challenges, knowledge gaps, and enabling technologies to achieve advanced levels of automation.