Engineers at the U.S. Department of Energy’s Argonne National Laboratory are investigating how insider actions could potentially compromise the passive safety systems in next-generation nuclear reactors. This research is crucial as these advanced reactors, including small modular designs, heavily depend on these safety systems, which are already employed in many operational reactors around the world.
The project aims to understand vulnerabilities within these systems before new reactor designs are constructed and licensed. As Darius Lisowski, group manager of reactor safety testing and analysis at Argonne, stated, “We want to know what would cause these systems to not work. In this project, we’re focusing on bad guys who might have authorized access and knowledge of inside workings. What could they do to make things break?”
Real-World Testing of Safety Systems
Rather than treating insider sabotage as a mere theoretical risk, Argonne researchers are conducting real-world tests using large-scale experimental facilities. The focus is on the Natural Convection Shutdown Heat Removal Test Facility, which enables engineers to simulate heat transfer in reactor systems when pumps and power are unavailable. The team is assessing various insider actions that could disrupt cooling, such as leaving access hatches open or intentionally blocking cooling pathways.
This project commenced over two years ago and has involved collaboration with Sandia National Laboratories, Oak Ridge National Laboratory, and Idaho National Laboratory. Initially, the team identified plausible sabotage scenarios and evaluated the potential severity and likelihood of such actions. Their findings are compiled in a report titled “Identifying Sabotage Risks and Adversarial Threats to Passive Decay Heat Removal Systems in Advanced Nuclear Reactors,” prepared for the International Atomic Energy Agency.
Researchers discovered that while nuclear plants are designed with multiple layers of protection, including controlled access, alarms, and redundancy, some vulnerabilities remain. Addressing these issues early, while reactor designs are still adaptable, is vital.
Strengthening Reactor Safety
To examine these vulnerabilities, Argonne researchers intentionally recreated credible sabotage scenarios within the test facility. They simulated conditions by blocking cooling paths and leaving components unsecured, allowing them to measure how systems would respond under stress.
“Our research is relevant and applicable to every U.S. nuclear vendor out there,” commented Matthew Bucknor, Argonne’s international nuclear security lead. The experiments do not target any specific reactor design but focus on common features shared across advanced reactor concepts.
Identifying risks at this stage can prevent minor oversights from escalating into significant issues later. As Lisowski noted, “By using redundancy, focusing on the most severe threats, and meeting strict design tests, we can ensure passive safety features are robust.” He emphasized the need for design improvements to occur early in the development of the next generation of reactors.
The project is backed by funding from the Department of Energy’s National Nuclear Security Administration, which has provided ongoing support for continued research. As countries increasingly turn to nuclear energy to satisfy rising electricity demands from sectors like artificial intelligence, data centers, and electrification, the researchers contend that safety and security measures must evolve alongside reactor technology.
