EXPERIMENTAL STUDY OF HEAT TRANSFER CHARACTERISTICS BASED ON TEMPERATURE VARIATIONS IN WATER COOLING TANK USING MEDIUM-SCALE EXPERIMENTAL FACILITY

Abstract

The failure of the active cooling system during the Fukushima-Daiichi reactor accident caused the melting of the reactor core. It became a reference for developing a passive cooling system for future nuclear reactor safety systems. Research on passive cooling systems based on natural circulation on a medium scale still needs to be carried out. Therefore, it is crucial to investigate the performance of components that consist of heating and cooling sections, considering that the natural circulation flow rate will depend on the heat transfer process. This study aims to characterize the heat transfer in the WCT component at the FASSIP-03 NT loop as a medium-scale experimental facility with a pipe length total of 11.71 meters and a height difference between the heater and cooler 3.05 meters. The experiment used temperature variations on the WHT for steady-state conditions, with variations of 60^°C, 70^°C, and 80^°C, respectively, for the experimental time of 72000 seconds. The results of this study obtained the highest value of decreasing the temperature of the hot fluid, which was 4.65^°C. Also obtained the thermal efficiency of the heat sink from variations in WHT temperature and showed the relationship of overall heat transfer coefficient and heat transfer, obtained successively: 310.235 W.m^-2.K^-1; 367.57 W.m^-2.K^-1; 402.86 W.m^-2.K^-1.