The heat transfer characteristics of steam condensation in a passive residual heat removal system heat exchanger (PRHR HX) are among the most important factors affecting the operational capability of marine nuclear power platform PRHR systems. This study aims to analyze the heat transfer characteristics of steam condensation in a PRHR HX and obtain the accurate heat transfer coefficient relationship.

The heat transfer characteristics of steam condensation in a PRHR HX are analyzed by building an experimental device with a power ratio of 1∶50.

The experimental results show that the heat transfer coefficient increases with the increase in steam pressure. The internal flow pattern of the PRHR HX is a stratified flow or wave flow-annular flow-wave flow. The maximum flow rate of HX vapor is 6.72 m/s when the system pressure is 0.52 MPa, and when the pressure exceeds 0.52 MPa, the steam velocity decreases with the increase in heating power. The proposed new correlation shows good agreement, with an error of ±8% between the calculated and experimental results.

This study can provide useful references for the design of reactor safety systems for marine nuclear power platforms.