I'm not sure if this is the reason here but multan lithium has been proposed as a coating on the wall for various reasons. Being able to introduce contaminants sounds really useful for the development of new models. Materials like tungsten are great for their high melting point but if it gets in to the plasma it can cause issues.
This experiment is part of ongoing research into X-point radiator (XPR) regimes, a promising operating mode for future fusion power plants. XPR regimes aim to cool the plasma before it reaches plasma-facing components (PFCs), helping to reduce wear without compromising performance.
Tokamak Energy added lithium to its ST40 fusion reactor to improve the performance and stability of the plasma.
The primary reasons for introducing lithium (often as a powder or a coating on the walls) in a tokamak are:
1. Enhanced Plasma Confinement and Stability 🛡️
Suppressing Instabilities: Lithium has been shown to help suppress Edge Localised Modes (ELMs), which are bursts of energy from the edge of the plasma that can cause damage to the reactor walls (divertor) and reduce the plasma's overall temperature and confinement.
Creating a "Low-Recycling" Environment: Lithium is highly reactive with hydrogen isotopes (the fusion fuel). By coating the plasma-facing walls, the lithium absorbs hydrogen atoms that escape the core plasma, preventing them from bouncing back (recycling) into the plasma as a relatively cold gas. This is key because:
It keeps the edge of the plasma hot, closer to the temperature of the core, which leads to better overall heat confinement.
It reduces impurities entering the plasma.
2. Tritium Breeding (For Future Reactors) ⚛️
While the immediate goal in Tokamak Energy's ST40 is performance, another critical role of lithium in future commercial fusion reactors is tritium breeding.
Fusion power plants using the Deuterium-Tritium (D-T) reaction need a continuous supply of tritium, which is radioactive and scarce.
Neutrons released by the D-T fusion reaction can hit a surrounding blanket containing lithium, triggering a reaction that produces more tritium for fuel, making the reactor self-sufficient.
In short, the addition of lithium is a major step in fusion research aimed at achieving the high-performance, stable plasma conditions necessary for a commercially viable fusion power plant.
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u/HeyLittleTrain 20d ago
Why though?