Thermal conductivity measurement with silica-coated hot wire for LiSiO pebble bed

Tanigawa, Hisashi; Tanaka, Yuichiro*; Enoeda, Mikio; Akiba, Masato

Effective thermal conductivity of a LiSiO pebble bed was measured by the hot wire method. The bare and the silica-coated Nichrome heaters were used as the hot wire. At 975 K, the effective thermal conductivity was not measured correctly by the bare hot wire. This is caused by that the electrical signal of the bare thermocouple is distorted due to electrical conductivity of LiSiO. Using the silica-coated hot wire, the effective thermal conductivity can be measured at temperatures ranging from room temperature to 975 K. The effect of the coating layer on the measured effective thermal conductivity was estimated to be small and corresponded to the experimental data. The hot wire method with silica-coating can be applied to the other ceramic breeder materials.