US study finds lithium in reactor vessel could boost nuclear fusion

A recent US-led study involving nine institutions has found that using lithium as a wall material in tokamak fusion reactors could significantly enhance fusion performance. Lithium coatings on reactor walls help stabilize plasma by creating an even temperature gradient from the plasma core to its edge, which is crucial for maintaining stable plasma conditions needed for commercial fusion. Unlike pre-applied lithium coatings, injecting lithium powder during fusion operation proves more effective, as it forms a self-repairing molten layer that protects the vessel walls from the extreme heat—temperatures hotter than the sun’s core—by creating a gas or vapor shield. This protective mechanism reduces wall erosion and limits unwanted material entering the plasma, thereby improving plasma-facing surface durability. The study also addressed concerns about fuel trapping in lithium, finding that the thickness of lithium coatings before plasma shots does not significantly affect fuel retention. Lithium’s ability to absorb fuel atoms rather than reflect them helps stabilize the plasma edge, enhance plasma confinement, and enable higher power densities—key factors for developing compact and efficient