Research on the passive residual heat removal capacity of supercritical carbon dioxide

To investigate the passive residual heat removal capacity of supercritical carbon dioxide (S-CO₂), this study takes a 12MWe lead–bismuth fast reactor as an example and analyzes two indirect S-CO₂ passive residual heat removal system (PRHRS) designs (design 1 based on steam generator (SG) and design 2 based on independent heat exchanger (IHEX)). One-dimensional modeling was conducted using the Modelica language, and detailed analysis was performed on important components. The passive residual heat removal capacity of S-CO₂ was evaluated through simulation calculations. The research results show that the maximum temperature of relevant design based on SG and IHEX does not exceed the pipeline design basis. Both design can reasonably and effectively remove the residual heat from the reactor core. The original equipment of the S-CO₂ Brayton recompression cycle can be directly used to remove residual heat without compromising the relatively simple arrangement. The reasons for the occurrence of peak flow rate are discussed. Meanwhile, an analysis of the outlet temperature of the loop under different pressures in the SG design concludes that the operating pressure of the scheme should exceed 8.5 MPa.