High temperature ultra-small modular reactor: Pre-conceptual design

This paper describes the pre-conceptual design for a high temperature (>1300 °C), ultra-small (1–10 MWe) modular reactor with a high efficiency (>50%) thermophotovoltaic (TPV) power-block. The integration of the TPV is attractive for increased efficiency over the heat cycles of traditional nuclear power plants (NPP) and increased inherent safety from the elimination of a working fluid. Allowing for heat removal through radiative and passive convective cooling, the design must operate at low power densities. A preliminary sampling of the design space was performed using coupled thermal and neutronic analysis on a simplified model. This study shows the viability of the design and reveals the favorability of using uranium nitride fuel that allow the core to operate safely at approximately 1–2 W/cm³ within the desired temperature limits. Although preliminary, the depletion and economic analyses reveal an operational time on the order of ten thousand days and approximately 43% savings in NPP capital costs.