Heat transfer performance tests using a half scale horizontal storage module

Spent nuclear fuel generated at nuclear power plants must be safely stored during interim storage periods. A horizontal storage module to safely store the spent nuclear fuel should be able to adequately emit the decay heat from the spent nuclear fuel. The horizontal storage module must ensure that the temperatures of the spent nuclear fuel assemblies are maintained within the allowable values for normal, off-normal, and accident conditions. Therefore, the horizontal storage module must be designed including heat removal capabilities with an appropriate reliability. However, the thermal conductivity of concrete is not good and the allowable temperature of concrete is lower than that of steel. Therefore, heat transfer performance tests were performed to evaluate the heat transfer performance in accordance with the ratio of the outlet to inlet of the air as well as the direction of the inlet and outlet of the air in the horizontal storage module. The influence that the direction of the inlet and outlet of the air reaches to the heat transfer performance was estimated to be minimal. The overall heat removal efficiencies were reduced as the mass flow rate at the outlet was reduced.