Journal of Nuclear Fuel Cycle and Waste Technology

In a high-level waste (HLW) repository, heat is generated by the radioactive decay of the waste. This can affect the safety of the repository because the surrounding environment can be changed by the heat transfer through the rock. Thus, it is important to determine the heat transfer coefficient of the atmosphere in the underground repository. In this study, the heat transfer coefficient was estimated by measuring the indoor environmental factors in the Korea Atomic Energy Research Institute Underground Research Tunnel (KURT) under forced convection. For the experiment, a heater of 5 kw capacity, 2 meters long, was inserted through the tunnel wall in the heating section of KURT in order to heat up the inside of the rock to 90 ℃, and fresh air was provided by an air supply fan connected to the outside of the tunnel. The results showed that the average air velocity in the heating section after the provision of the air from outside of the tunnel was 0.81 m/s with the Reynolds number of 310,000 ～ 340,000. The seasonal heat transfer coefficient in the heating section under forced convection was 7.68 W/m2․K in the summer and 7.24 W/m2․K in the winter

Keywords

High-level Radioactive Waste,Heat Transfer Coefficient,KURT,Reynold';s Number,Forced Convection