Evaluation of thermal conductivity for liquid lead lithium alloys at various Li concentrations based on measurement and evaluation of density, thermal diffusivity and specific heat of alloys

Abstract

The thermophysical properties of lead lithium alloy (Pb–Li) are essential for the design of liquid Pb–Li blanket system. The purpose of the present study is to make clear the density, the thermal diffusivity and the heat conductivity of the alloys as functions of temperature and Li concentration. The densities of the solid alloys were measured by means of the Archimedean method. The densities of the alloys at 300K as a function of Li concentration (0at%<χLi<28at%) were obtained in the equation as ρ(300K)[g/cm3]=−6.02×10−2×χLi+11.3. The density of the liquid alloys was formulated as functions of temperature and Li concentration (0at%<χLi<30at%), and expressed in the equation as ρ[g/cm3]=(9.00×10−6×T−7.01×10−2)×χLi+11.4−1.19×10−3T. The thermal diffusivity of Pb, Pb–5Li, Pb–11Li and Pb–17Li were measured by means of laser flash method. The thermal diffusivity of Pb–17Li was obtained in the equation as αPb–17Li[cm2/s]=3.46×10−4T+1.05×10−1 for the temperature range between 573K and 773K. The thermal conductivity of the Pb–17Li at the temperature of 773K was newly obtained and expressed in the equation as λ[W/mK]=4.47×10−2χLi2−0.08χLi+14.9. The dependence of Li concentration on the thermal diffusivities of the alloys was larger at higher temperature. The temperature dependence of the thermal conductivities of the alloys was larger when the Li concentration in the alloys was higher.