Reactivity safety analysis of an air-cooled nuclear thermal propulsion reactor

As the most promising alternative to chemical propulsion, nuclear thermal propulsion technology has been extensively studied in recent years. However, most existing research lacks comprehensive safety assessments of reactor designs. This study replicates an air-cooled nuclear thermal propulsion reactor. And using a cross-dimensional coupled solution approach, the reactor design is evaluated from both normal operation and transient responses. For the normal operation, the diversity and redundancy of the reactor’s shutdown means are examined, leading to the conclusion that the reactor possesses an adequate shutdown margin and a negative fuel coefficient. For transient conditions, by simulating the reactor response under Proportion-Integration-Differentiation (PID) control, it is demonstrated that the reactor is capable of withstanding multiple types of reactivity insertion accidents (RIAs). This paper can provide a methodological foundation for subsequent safety evaluation in the design of nuclear thermal propulsion reactors.