Liquid Lithium Applications in Fusion Technology

Liquid lithium is emerging as a versatile plasma-facing material in magnetic confinement fusion devices. Its low atomic number minimises plasma dilution, while its high heat capacity and latent heat of vapourisation enable passive protection of structural surfaces. Liquid lithium layers can absorb steady-state heat fluxes in excess of 10 MW m⁻² and withstand transient loads such as edge-localised modes by self-regulating surface temperature through vapour shielding. Capillary porous systems ensure uniform lithium film formation and continuous replenishment, whereas lithium vapour divertor concepts employ volumetric radiation to cool and detach exhaust plasmas. These approaches collectively aim to enhance heat-handling capability, reduce material erosion and control tritium retention, advancing the viability of next-generation fusion reactors.

Research from Nature Portfolio

Recent studies have demonstrated that liquid metal walls can self-stabilise under extreme plasma heat fluxes via oscillatory vapour shielding. Experiments with molten tin revealed cyclical formation and collapse of vapour clouds in response to steady and pulsed plasma loads, effectively buffering the substrate from peak thermal stresses. The observed dynamic equilibrium between plasma heat exhaust and vapour-mediated recombination processes establishes a robust mechanism for surface temperature control. These insights provide a foundational basis for extending oscillatory vapour-shielding concepts to liquid lithium applications, promising enhanced resilience of plasma-facing systems in fusion environments.

Liquid Lithium Applications in Fusion Technology publication trend

The graph below shows the total number of articles in liquid lithium applications in fusion technology across all publications each year (not limited to Nature Index journals).

Technical terms

Plasma-facing component: The interface between the high-temperature plasma and reactor vessel, designed to withstand intense heat and particle bombardment.

Divertor: A specialised chamber region that extracts heat and impurities from the plasma, protecting main chamber walls and enabling controlled exhaust.

Vapour shielding: A passive protection mechanism in which vapourised material forms a radiating cloud that absorbs plasma heat, reducing thermal load on the surface.

Capillary porous system (CPS): A porous matrix that retains and distributes liquid metal by capillary action, ensuring uniform film formation under operational conditions.

Magnetohydrodynamic flow: The behaviour of electrically conducting fluids under the influence of magnetic fields and electric currents, governing liquid metal movement.

Edge-localised mode: A transient plasma instability characterised by rapid bursts of energy and particles from the edge region, imposing short-lived high heat loads.

References

1. Oscillatory vapour shielding of liquid metal walls in nuclear fusion devices. Nature Communications (2017).
2. Thermoelectric magnetohydrodynamic flow in a liquid metal-infused trench. Journal of Fluid Mechanics (2025).
3. The effect of gas injection location on a lithium vapor box divertor in NSTX-U. Nuclear Fusion (2023).
4. Performance of liquid-lithium-filled 3D-printed tungsten divertor targets under deuterium loading with ELM-like pulses in Magnum-PSI. Nuclear Fusion (2021).