Henry's constant of helium in liquid lead-lithium alloys

Abstract

Information about the solubility of helium in liquid metals is of fundamental relevance in the design of the future nuclear fusion reactors, since the formation of helium bubbles inside the breeding blankets of the reactors constitutes a threat to the durability of the devices and, more importantly, to the efficiency of tritium recovery. In the present work, we report molecular dynamics simulations results of the solubility of helium in a variety of lead-lithium alloys. Simulation experiments have been combined with a classical perturbative procedure able to compute the free energy of insertion of a helium atom inside a liquid metal bath, directly related to the solubility of helium. As the most important case, the eutectic state (16%Li-84%Pb at 508 K) has been explored in full details, predicting a solubility value of $(6.1\pm 1.4)\times {10}^{-16}{\mathrm{Pa}}^{-1}$. In addition, several temperatures and atomic fractions of the solvent have been explored. For any temperature, we have found that the solubility of helium in pure lithium is lower than in pure lead. We have also studied the 1000 K isotherm and observed that there is a minimum solubility value for ∼ 80%Li-20%Pb. The observed trends indicate that solubilities rise with increasing temperatures.