Dissolution of deuterium into Pb-Li and determination of the Sieverts’ constant

The development of liquid breeding blanket technologies for ITER and DEMO, based on eutectic Pb-Li, faces significant challenges due to the unknown solubility of hydrogen isotopes in Pb-Li. Reported values in the literature span several orders of magnitude, creating substantial uncertainty in experimental design and data interpretation of Tritium Extraction and Removal System (TERS) technologies. In this work, deuterium is dissolved into eutectic Pb-Li using a stationary method and quantified via a mass balance analysis performed at the point of steady-state. The average atomic deuterium concentrations dissolved in Pb-Li are 1.5 ± 0.3 and 0.7 ± 0.2mol m$^{−3}$, at dissolving pressures of 947 and 472 hPa, respectively, and 673 K. The obtained Sieverts’ constant, (4.3 ± 1.1) × 10$^{−3}$ mol m$^{−3}$ Pa$^{−1/2}$ at 673 K, is determined considering deuterium permeation through the chamber walls and with a known Pb-Li composition of 15.2 ± 0.2 at.% Li. This value is presented with a rigorous uncertainty analysis and widely discussed with regard to previously reported data in the literature.