Effective thermal conductivity of U-shaped heat pipe

Abstract

The nuclear power station severe accident in Fukushima Daiichi became an important lesson learn to involve the passive cooling system in order to enhance the safety in a nuclear power station when prolonged station blackout occur. A U-shaped heat pipe is proposed as one of alternative passive cooling technology to absorb the decay heat generation in the cooling tank that connected to the reactor cavity cooling system. This research objective is to know the effective thermal conductivity of the U-shaped heat pipe. The effective thermal conductivity is an important factor to know the effect of the U-shaped heat pipe to remove the decay heat generation to the heat sink. An experiment was conducted to know the effective thermal conductivity of U-shaped heat pipe. The air cooling velocities on a bonded-fin heat sink in the condenser section were used as a parameter to obtain the effective thermal conductivity of U-shaped heat pipe. The air cooling velocities were varied at 0.65, 0.74, 1.02, and 1.21 m/s. The experiment results showed that the effective thermal conductivity of 35.37 was obtained at the highest variation of air cooling velocity on a bonded-fin heat sink in the condenser section. The result obtained shows that U-shaped heat pipe as a heat transfer device has thermal conductivity 35.37 times greater than the solid U-shaped Copper with the same geometry and dimension. This investigation results can be used to justify the use of heat pipes as a good passive cooling system in cooling tanks connected to Reaktor Daya Eksperimen reactor cavity cooling system.