Breeder Blanket Safety
The lithium-bearing blanket breeds tritium and is reactive with water; it is handled in inert, contained, and monitored systems.
The breeder (Hyperion) surrounds its plasma with a lithium-bearing blanket that captures 14 MeV neutrons to breed tritium and helium-3 and to carry heat. Lithium is chemically reactive — particularly with water and air — so blanket safety centers on keeping it in inert, contained conditions and on managing the tritium it produces.
Blanket hazards and controls
- Lithium reactivity: inert cover gas, dry systems, and separation from water.
- Tritium generation: bred tritium extracted and returned to the fuel cycle under permeation control.
- Neutron multiplication: a multiplier raises neutron yield toward the target breeding ratio — a fixed material effect, not a chain reaction.
- Heat and activation: the blanket carries heat and becomes activated — handled remotely.
The tritium breeding ratio is treated as a design lever across 1.1 / 1.5 / 1.8, balancing tritium self-sufficiency against inventory and engineering. A key safety point: blanket neutron multiplication increases neutron yield by a bounded material factor and is not a chain reaction — it cannot run away. Lithium-water reactions are prevented by design separation and inerting, and any blanket tritium is contained by permeation barriers.
End of life
Activated blanket modules are replaceable and are handled by remote maintenance, then stored to decay. With low-activation materials, they become recyclable or near-surface waste on human timescales, not long-lived spent fuel.
The burner (Aegis / MetroVolt) has no breeding blanket and so carries none of these hazards.