Thermal Characteristics of Vertical Straight Wickless-Heat Pipe with Low Temperature Source

The Fukushima Dai-ichi nuclear power plant severe accident provided a lesson to involve the passive cooling system (PCS) in order to enhance the safety aspect in small modular reactor (SMR) being studied in Indonesia. This investigation is dealing with the research on the application of the vertical straight wickless-heat pipe (VSWHP) as PCS in water cooling tank (WCT). This research objective is to know the heat transfer characteristics and thermal resistance of VSWHP applied at low temperature source. The experiment was carried out by varying the temperature of pool water as an evaporator heat load source, and working fluid filling ratio in VSWHP. The coolant volumetric flow rate in the water jacket as heat absorber was kept constant. The investigation results showed that the lowest thermal resistance of 0.0154 °C/W was obtained when VSWHP operated at higher water temperature source, filling ratio of 80%, and initial pressure of 2666.4 Pa. It is concluded that the VSWHP could be applied at the relatively low temperature load source with good thermal characteristic. This investigation results can be considered to propose VSWHP as an emergency PCS and to improve the safety aspect in SMR.