Experimental study on the influence of inclination on operating characteristics of secondary side passive residual heat removal system

•A scaled experimental facility of the secondary side PRHRS was designed and built.•The variation of outlet temperature of the heat exchanger is affected by thermal stratification.•The steady-state pressure decreases with the increase of the inclination angle under right-side inclination conditions.•The inclined conditions weaken the thermal stratification in the cooling water tank. The present work discusses the operating characteristics of the secondary side passive residual heat removal system (PRHRS) of an offshore floating nuclear plant (OFNP). A scaled experimental facility was built on a platform that can be inclined to a certain angle. Experiments were conducted in horizontal and various inclined conditions, and the transient response characteristics and steady-state operating characteristics of the PRHRS were obtained. The experimental results reveal that different inclined directions will change the potential height difference between the cold and heat sources and affect the natural circulation capacity of the system. In general, due to the small inclination of the floating platform in the ocean, the residual heat can be effectively exported by PRHRS. Thermal stratification in the cooling water tank has significant effect on the evolution process of outlet temperature of the passive residual heat removal heat exchanger, and the influence of thermal stratification on the outlet temperature of the heat exchanger decreases under inclined conditions. The research results in this paper can provide some guidance for the design of operating rules of the secondary side PRHRS.