Exciting advancements in nuclear fusion technology are on the horizon, driven by the unexpected discovery of a new process for producing lithium-6, a critical isotope necessary for sustainable fusion reactors. This breakthrough could bring us closer to harnessing limitless power from fusion energy.
The simplest fusion process combines two hydrogen isotopes, deuterium and tritium, generating helium, a neutron, and significant energy. However, sourcing tritium, a rare and radioactive hydrogen isotope, presents challenges due to its high cost and scarcity. Currently, breeder reactors attempt to synthesize tritium by bombarding lithium with neutrons.
Lithium naturally exists in two stable isotopes: lithium-7, which constitutes 92.5% of the element, and the rarer lithium-6. This less common isotope is far more efficient in reacting with neutrons to produce tritium in fusion reactions. However, the separation of these isotopes has historically been a challenge, traditionally relying on a toxic mercury-based process that has not been utilized in Western nations since the 1960s, forcing reliance on dwindling pre-ban stockpiles of lithium-6.
Researchers at ETH Zurich have serendipitously discovered a safer and more effective method to isolate lithium-6 while investigating ways to purify water contaminated by oil drilling. They observed that cement membranes embedded with a custom compound, zeta vanadium oxide, effectively captured lithium, particularly favoring the isolation of lithium-6.
According to the researchers, zeta vanadium oxide features tunnels lined with oxygen atoms through which lithium ions move. They found that these tunnels are precisely sized to bind lithium-6 more strongly than its counterpart. While the exact reason for this preference remains unclear, simulations suggest that interactions at the tunnel edges play a crucial role.
Currently, the team has managed to isolate less than a gram of lithium-6, but they are optimistic about scaling this process to produce tens of kilograms of the isotope, which is vital for the daily operations of commercial fusion reactors that may require tons of lithium-6. Despite these advances, the researchers acknowledge that significant challenges still lie ahead in addressing issues related to plasma reactors and laser ignition for fusion.
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