Calculation of Transport Properties of Polonium in Lead Bismuth Eutectic at High Temperature

ABSTRACT In this study, the protective gas Ar of lead bismuth eutectic (LBE) operating environment and the substances such as Po, Pb, Bi, Po 2 , Bi 2 , PbPo produced during LBE operation were divided into three‐atom group (Po 2 ‐Po, Po 2 ‐Pb, Po 2 ‐Bi, Bi 2 ‐Po, Bi 2 ‐Pb, Bi 2 ‐Bi, PbPo‐Po, PbPo‐Pb, PbPo‐Bi) and four‐atom group (Po 2 ‐Po 2 , Po 2 ‐Bi 2 , Po 2 ‐PbPo, Bi 2 ‐Bi 2 , Bi 2 ‐PbPo, PbPo‐PbPo). The intermolecular interaction potential of each component was calculated respectively, and the Lennard‐Jones (L‐J) parameters of each component were obtained according to the relevant formula. Based on these L‐J parameters, the transport properties such as binary diffusion coefficient, viscosity coefficient, and thermal conductivity at high temperature were calculated. The results show that the well depth of each component of the three‐atom group is much greater than that of the four‐atom group, which results in the binary diffusion coefficient of each component of the three‐atom group being much smaller than that of the four‐atom group. In addition, it was found that the viscosity coefficient and thermal conductivity of the same substance seemed to have a fixed ratio, so we calculated the Prandtl number of Po 2 and Bi 2 , and compared them with the Prandtl number of substances such as air, water, and argon, and found that the thermal conductivity of Po 2 and Bi 2 was better than that of water and argon, but slightly lower than that of air. Finally, we calculated the rate constant of reaction PbPo + Po → Po 2 + Pb in the temperature range of 400–2000 K at standard pressure (1.0 bar).