This paper investigates the response of the DynMo-CBC space nuclear reactor power system to simulated cybersecurity attacks during a startup transient and demonstrates the effectiveness of the mitigation measures. The system nominally generates 134 kW(electric) continuously for 12 years and does not have a single-point failure in reactor cooling and energy conversion. The reactor core is divided into three hydraulically independent sectors, each having a separate loop with a single shaft, closed Brayton cycle (CBC) turbomachinery unit. A He-Xe gas mixture with a molecular weight of 40 g/mol cools the reactor core sectors and is the CBC unit’s working fluid.

This paper examines the effects of simulated false data injection attacks (FDIAs) on the operation parameters of the power system. The simulated FDIAs decrease or increase the external reactivity insertion beyond nominal to cause spikes in the reactor’s power and temperatures. The results demonstrate the effectiveness of the programmable logic controller regulating the control drums’ drive motors. It mitigates the effects of the simulated FDIAs on the transient operation of the power system and shortens the recovery time after the termination of the simulated cyberattacks.