The Deuterium-Tritium Fuel Cycle
The breeder (Hyperion) runs on deuterium and tritium, breeding its own tritium so the cycle closes with only water-derived and abundant inputs.
The reaction at the core
The breeder (Hyperion) fuses deuterium with tritium. This reaction releases a helium nucleus and an energetic 14 MeV neutron. The neutron carries most of the released energy and is also the agent that breeds new tritium in the surrounding lithium blanket, which is what makes the cycle self-sustaining.
Canonical design parameters
The breeder is a spherical tokamak. Its design-point figures include a scientific gain (Q) of 3.424, fusion power of 88.7 MW, plasma current of 9.86 MA, a peak field of 16.84 T (about 8 T on axis), and negative triangularity of -0.30. These are computed design targets, not measurements.
- Fuel in: deuterium (from water) and lithium (for breeding)
- Fuel bred: tritium, in a roughly 4 kg/yr class
- Byproduct isotope: helium-3, about 1.97 kg/yr class
- Energy carrier: 14 MeV neutrons, at a 5.44% neutron fraction context
Honest gate
Construction begins Q2 2027, with first-of-a-kind first tritium targeted near 2030; there is no hardware net-gain claim before that milestone. See the burner's deuterium-helium-3 cycle and the closed fuel cycle.
Neutrons that both power and breed
What makes the deuterium-tritium cycle self-sustaining is that its energetic neutron plays two roles at once: it carries most of the released energy and it is the agent that manufactures the next generation of fuel. Capturing that neutron well is therefore both an energy question and a fuel question, which is why blanket design sits at the center of the machine rather than at its periphery.