Thermal conductivity and electrical resistivity of liquid Ag–In alloy

Abstract

ABSTRACT To understand and predict the progression of core meltdown accidents in nuclear power plants, it is important to understand the behavior of molten core materials. We focused on the melting behavior of Ag–In–Cd alloys used in the control rods of pressurized water reactors that are known to melt first when a severe accident occurs. To obtain fundamental knowledge about these alloys, we studied the thermal conductivity of Ag–In binary alloys in this study. We evaluated thermal conductivity using two approaches: evaluating from thermal diffusivity up to 873 K measured by the laser-flash method, and calculating based on the Wiedemann–Franz law using the electrical resistivity up to 1273 K measured by the four-probe method. The values of thermal conductivity of liquid Ag–In alloys obtained by these two methods agreed well except for pure indium. Although Ag is known as a material that has one of the highest thermal conductivities, the thermal conductivity of liquid Ag–In alloys is much lower than that of pure liquid Ag (177 W/mK at 1273 K), but almost the same or less than that of liquid In (59.2 W/mK at 1273 K) in all Ag1− x In x (x = 0.2–0.8) alloys at all temperatures in this measurement.