Experimental study on a passive dome containment cooling system using heat pipe technology: Effect of heat pipe structure

Heat pipes integrated into the building envelope structures can absorb or dissipate excess heat, thereby reducing the energy consumption of heating or cooling systems and enhancing thermal comfort. Nuclear power plant containment structures also have the demand for the prompt heat removal during accident scenarios. This study proposes a passive containment cooling system utilizing heat pipe technology in the dome (HPTID-PCCS) to enhance nuclear safety. An experimental investigation was conducted to evaluate the impacts of the evaporator-to-condenser length ratio of the heat pipe and the fin structure of the evaporator on the thermal conductivity and cooling efficiency of the HPTID-PCCS. The results showed that the thermal conductivity and cooling efficiency increased when the evaporator-to-condenser length ratio decreased. When internal heat dissipation was 1200 W, geometric optimization of the evaporator-to-condenser length ratio from 7:10 to 5:12 resulted in a 17.41 % reduction in dome air temperature differential, an 11.88 % improvement in the heat transfer power of the heat pipe, and 4.31 % suppression of terminal entransy dissipation rate. Under natural convection conditions within the dome, finned evaporator configurations demonstrated enhanced thermal transport capacity under moderate heat dissipation regimes. When the internal heat dissipation was 400 W, the air temperature difference between inside and outside the dome decreased by 26.63 % (with a smooth surface on the evaporator) and 28.12 % (with fins on the evaporator), respectively. However, under high internal heat dissipation conditions, the irreversibility of the heat transfer process about the heat pipe increased and the improvement of cooling efficiency was limited.