Cyberattack Scenario Development Targeting Nuclear Power Plants Using I&C Focused System Dynamics

The increasing digitalization of nuclear power plant instrumentation and control (I&C) systems has introduced new cyber-induced risk pathways that are not adequately captured by traditional, network-centric cybersecurity analyses. In particular, the malicious manipulation of digital control logic or sensor signals can propagate through plant feedback structures and manifest as delayed or indirect physical consequences.This work proposes a consequence-oriented framework for cyberattack scenario development using an I&C-focused system dynamics (SD) modeling approach. Rather than emphasizing intrusion mechanisms or network architectures, the framework concentrates on the physical and digital I&C layers, where cyber actions translate into measurable system behavior. The methodology systematically transforms legacy reactor documentation into an executable SD model, while the Molten Salt Reactor Experiment (MSRE) is used as a representative case study due to the availability of publicly accessible design and operational documentation.A set of representative scenarios is evaluated for validation and verification purposes by comparing them with an existing MSRE MELCOR input deck. These scenarios include steady-state operation, drain tank valve opening to represent both cyber-physical manipulations and coolant pump speed perturbations covering reduced, zero, and increased flow conditions to depict both cyber-physical manipulations and cyber-specific attacks.The results demonstrate that the SD model captures the dominant causal relationships, response timing, and trend behavior observed in MELCOR simulations, despite differences in the transient resolution, numerical smoothness, and value differences. The difference is caused by the confidential regions not publicly available for the MSRE documents, resulting in an incomplete MSRE I&C SD model. Nevertheless, the proposed framework provides a practical and extensible foundation for consequence-driven nuclear cybersecurity assessments and supports future integration with automated model generation techniques.