Lithium-6 Enrichment and Breeding

Tritium is bred on lithium-6; enriching the lithium in ⁶Li raises capture and is one of the strongest levers on TBR.

The reaction that makes tritium

Tritium breeding in the blanket runs on two reactions with lithium. The dominant one at low energy is ⁶Li(n,α)³H, which captures a neutron on lithium-6 to produce tritium and helium-4, releasing 4.8 MeV of useful heat. A second channel, ⁷Li(n,n'α)³H, breeds on lithium-7 but only for fast neutrons and consumes energy.

Natural lithium is only about 7.6% lithium-6, the rest being lithium-7. Because ⁶Li is the workhorse breeder, enriching the lithium in lithium-6 raises the breeding cross-section available and is one of the most direct ways to increase TBR. Reference blanket studies assume enrichment well above natural abundance.

Enrichment trades

• Higher ⁶Li fraction → higher breeding, higher TBR
• Enrichment is a supply-chain and process undertaking
• Over-enrichment past a point yields diminishing returns as the blanket becomes optically thick
• ⁷Li still contributes fast breeding and neutron economy

A supply consideration

Lithium-6 is itself a controlled, limited material, and enriched-lithium supply is part of the breeder's feedstock planning. It is a real engineering and sourcing constraint, treated here as a physics-and-process design factor. It carries no economics on this page by policy — only its role as a TBR lever.

This page describes a design-and-simulation study, not a built machine. Construction begins Q2 2027; first-of-a-kind (FOAK) first tritium is targeted near 2030. No net-gain claim is made before FOAK.