Preliminary experiment of vertical straight wickless-heat pipe as passive cooling system in irradiator

The multipurpose Irradiator in Indonesia with capacity of 2 MCi Co-60 radioactive source was built to support food security. When not operated, the Co-60 is stored in the pool to keep the radiation not to exposure to environment. The decay heat generation of Co-60 could increase the pool water temperature. To improve safety especially during SBO conditions, the pool water should be passively cooled using a vertical straight wickless-heat pipe. The objective of this experimental study is to investigate the heat transfer phenomena and the thermal performance of the vertical straight wickless-heat pipe as passive cooling system in the irradiator pool. Vertical straight wickless-heat pipe with inner diameter of 57 mm and total length of 1000 mm was charged with demineralized water of working fluid with filling ratio of 55%. This experiment was conducted with varied pool temperature, and air coolant velocity in the condenser section. The experiment results obtained that the lowest thermal resistance of wickless-heat pipe is 0.03 °C/W when heat pipe is operated at pool temperature of 90°C and air coolant velocity of 1 m/s. It can be concluded that the vertical straight wickless-heat pipe has good thermal performance to absorb the heat generation in the irradiator pool. The results of this study are expected to provide a more complete management thermal knowledge to improve the safety of Irradiator.