Equilibrium evaporation test of lead-bismuth eutectic and of tellurium in lead-bismuth

Ohno, Shuji  ; Nishimura, Masahiro ; Hamada, Hirotsugu  ; Miyahara, Shinya  ; Sasa, Toshinobu*   ; Kurata, Yuji*

A series of equilibrium evaporation experiment was performed to acquire the essential and the fundamental knowledge about the transfer behavior of lead-bismuth eutectic(LBE) and impurity tellurium in LBE from liquid to gas phase. The experiments were conducted using the transpiration method in which saturated vapor in an isothermal evaporation pot was transported by inert carrier gas and collected outside of the pot. The size of the used evaporation pot is 8cm inner diameter and 15cm length. The weight of the LBE pool in the pot is about 500g. The investigated temperature range was 450deg-C to 750deg-C. From this experiment and discussion using the data in literature, we have obtained several instructive and useful data on the LBE evaporation behavior such as saturated vapor pressure of LBE, vapor concentration of Pb, Bi and Bi2 in LBE saturated gas phase, and activity coefficient of Pb in the LBE. The LBE vapor pressure equation is represented as the sum of Pb, Bi and Bi2 vapor in the temperature range between 550deg-C and 750deg-C as logP[Pa]=10.2-10100/T[K]. The gas-liquid equilibrium partition coefficient of tellurium in LBE is in the range of 10 to 100, with no remarkable temperature dependency between 450deg-C and 750deg-C.