Breeding Blanket Control
The blanket surrounding a D-T plasma captures neutrons to breed tritium and carry away heat, and its coolant and purge flows are actively controlled.
What the blanket does
A breeding blanket surrounds the plasma and does three jobs: it absorbs the energetic fusion neutrons and converts their energy to heat, it breeds tritium by reactions of neutrons with lithium, and it shields the magnets and structure. Control keeps its coolant flow and temperature within limits and manages the recovery of bred tritium.
Tritium breeding
Neutrons captured by lithium produce tritium and helium. A neutron multiplier such as beryllium or lead boosts the neutron count so that more than one tritium can be bred per fusion neutron, needed to replace the tritium burned plus losses. The tritium breeding ratio measures this; a value above one is required to sustain the fuel cycle.
Coolant and purge control
The blanket's coolant removes the deposited heat and feeds the power-conversion system, so its flow and temperature are regulated like any heat exchanger, with the added constraint of neutron-driven heating that follows the fusion power. A separate purge stream sweeps bred tritium out of the breeder material for recovery; its flow and pressure are controlled to maximize recovery while limiting tritium permeation into the coolant.
- Absorbs neutrons, breeds tritium, shields the magnets
- Neutron multiplier raises the breeding ratio above one
- Coolant flow tracks neutron-driven heat load
- Purge stream recovers bred tritium
Kronos context
The Hyperion breeder targets a modeled tritium breeding ratio of 1.8, comfortably above unity in the design study, to supply its own fuel and build inventory. Blanket control ties directly to fuel-cycle and tritium-accounting systems, since bred tritium must be measured and reconciled. The machine is a design and simulation case, and no hardware net-gain claim is made before first tritium, targeted around 2030.
The blanket is where fusion energy becomes usable heat and where the fuel cycle is closed.