Recent media coverage in Interesting Engineering, Phys.org, and PPPL news reports new results on lithium walls and lithium plasma-facing components in fusion reactors, based on experiments on the DIII-D tokamak.

The underlying study by Morbey, Effenberg et al. provides the first direct comparison between pre-deposited lithium films and lithium introduced during plasma operation via powder injection. The central result is that fuel retention in lithium plasma-facing components is independent of the thickness of pre-deposited lithium coatings. Instead, hydrogen isotope retention is dominated by lithium–deuterium co-deposition formed during plasma exposure.

This identifies a clear physics distinction between static and dynamic surface regimes in tokamak plasma–surface interactions. Pre-deposited lithium films exhibit surface-limited trapping, while co-deposited Li–D layers formed during operation enable enhanced retention without a diffusion barrier. As a result, fuel inventory in lithium walls is governed primarily by in-situ plasma-driven deposition processes, not by initial coating properties. These findings are directly relevant for tritium management in fusion reactors. Lithium walls and lithium plasma-facing components enable low-recycling boundary conditions, improved edge stability, and high-performance operation in tokamaks. At the same time, the strong affinity of lithium for hydrogen isotopes requires predictive control of co-deposition, especially in cold or poorly accessible regions where fuel can accumulate.

This work is part of a broader research project led by Florian Effenberg and collaborators on lithium wall conditioning and real-time coating in tokamaks like DIII-D and KSTAR. Current efforts focus on predictive modeling of lithium transport, co-deposition, and surface evolution, as well as integration of impurity injection into plasma control strategies. The goal is to establish lithium wall conditioning as a controllable actuator for impurity suppression, edge stability, and fuel management in future reactor scenarios.

The results have been published here: M. Morbey, F. Effenberg et al, 'Deuterium retention in pre-lithiated samples and Li–D co-deposits in the DIII-D tokamak', Nuclear Materials and Energy 43, 101915, 2025, https://doi.org/10.1016/j.nme.2025.101915