Abstract: The PRHRS operation characteristics have been experimentally studied under different initial IRWST temperature conditions. The experimental results are compared in this paper, such as core inlet/outlet temperature, system pressure, nature circulation flow rate of PRHRS, heat exchange power. The comparison of the experimental results showed that the lower initial IRWST temperature caused the core inlet/outlet temperature and system pressure drop faster, the PRHR HX outlet temperature is lower but the heat exchange power is higher, the trends of nature circulation flow rate of PRHRS is similar.