Passive decay heat removal in the PeBR concept for nuclear thermal propulsion Available to Purchase

Passive decay heat removal enhances the safety of a nuclear propelled spacecraft and could increase its I_sp by up to 4 percent. The large height‐to‐diameter ratio (≳1.5) of the PeBR provides an effective means for passive removal of decay heat from the reactor core after firing. A multi‐dimensional transient heat conduction/radiation model of the PeBR core and surrounding structures is developed to investigate the potential for passive decay heat removal. The effective conductance of the core region includes both conduction and radiation contributions and the thermophysical properties of the fuel and core structure materials are taken to be temperature dependent. Results indicate that passive decay heat removal, following a short period of active cooling (600–1000 seconds), would maintain the PeBR core safely coolable with the peak fuel temperature well below 3400 K.