Study of various Brayton cycle designs for small modular sodium-cooled fast reactor

• Application of closed Brayton cycle for small and medium sized SFRs is reviewed.
• S-CO2, helium and nitrogen cycle designs for small modular SFR applications are analyzed and compared in terms of cycle efficiency, component performance and physical size.
• Several new layouts for each Brayton cycle are suggested to simplify the turbomachinery designs.
• S-CO2 cycle design shows the best efficiency and compact size compared to other Brayton cycles.

Many previous sodium cooled fast reactors (SFRs) adopted steam Rankine cycle as the power conversion system. However, the concern of sodium water reaction has been one of the major design issues of a SFR system. As an alternative to the steam Rankine cycle, several closed Brayton cycles including supercritical CO2 cycle, helium cycle and nitrogen cycle have been suggested recently. In this paper, these alternative gas Brayton cycles will be compared to each other in terms of cycle performance and physical size for small modular SFR application. Several new layouts are suggested for each fluid while considering the turbomachinery design and the total system volume.