Chemical thermodynamics of fusion reactor breeding materials and their interaction with tritium

• Published in: Journal of nuclear materials 1985-01, Vol.130, p.454-464
• Main Authors: Ihle, H.R., Wu, C.H.
• Format: Article
• Language: English
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/0022-3115(85)90332-0

Liquid lithium, lithium alloys (solid and liquid) and ceramic lithium compounds are candidate breeding materials for (D,T) fusion reactors. Besides their tritium breeding capability, which results from neutron capture, their thermochemical properties and their interaction with tritium are of particular interest. A good knowledge of the physical and chemical properties of liquid lithium exists; and the systems Li-LiH, Li-LiD and Li-LiT have been studied in great detail. For dilute solutions of D 2 in liquid lithium, Sieverts' law was found to be valid down to an atom fraction of x D = 10 -6 ; in the vapor, lithium polymers up to Li 4 and lithium deuterides are found. In the system liquid Li-Pb, the solubility of D 2 was measured as a function of temperature and alloy composition, and correlated with the activities of the constituent metals. The solubility of D 2 was found to obey Sieverts' law at low concentrations, and is many orders of magnitude smaller than that in liquid lithium. This holds also for solid “Li 7 Pb 2”. Vaporization studies yielded data on the thermal stability of the oxides: Li 20, γ-LiAlO 2, β-Li sAlO 4, LiAl 5O 8, Li 2ZrO 3, Li 4ZrO 4, Li 8ZrO 6, Li 2SiO 3 and Li 4SiO 4. Tritium diffusivity was studied in Li 2O, γ-LiAlO 2, β-Li 5AlO 4 and Li 4SiO 4. A large number of gaseous lithides were detected during these studies.