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How can a lithium blanket produce tritium for a fusion reactor?

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3D illustration of the interior reaction chamber of a tokamak fusion reactor, showing a large, cylindrical, metallic structure with curved walls and bright light panels. — fusion reactor A tokamak is a device used in nuclear-fusion research for magnetic confinement of plasma.

In a deuterium-tritium (D-T) fusion reactor, the lithium blanket serves as a critical component for fuel self-sufficiency by capturing neutrons produced during the fusion process.1

When deuterium and tritium nuclei fuse, they release high-energy neutrons (14.1 MeV) that are not affected by magnetic fields and escape the plasma. These neutrons are captured by the surrounding lithium blanket. Through nuclear reactions within this blanket, the lithium absorbs the neutrons to produce tritium (tritons), which can then be extracted and fed back into the plasma as fuel.1

This process is essential because tritium does not occur naturally in significant quantities. By utilizing these waste neutrons to generate more fuel, D-T fusion reactors effectively function as a closed-loop system, using deuterium and lithium as their primary fuel sources.1