A future deuterium–tritium power plant needs more than a hot plasma.
Follow the blanket system through fuel production, heat collection and shielding. These functions interact across an assembly and its supporting equipment.
A functional map / not to scale
Follow a neutron outward.
D–T plasma Neutrons leave the plasma
First wall
Breeding region Lithium-containing breeder+ coolant circuit
Shield
Protected equipment
Select a job below. The diagram highlights the relevant function; the notes explain the external systems and evidence needed too. Material choices and geometry change the interactions.
Fuel / a complete loop
Make tritium available to the fuel cycle.
In a breeding blanket, fusion neutrons interact with lithium-containing material to produce tritium. Recovery and return to the fuel cycle are separate system requirements. Producing tritium locally is one step toward sustained fuel supply.
Evidence to ask for: Does the reported result cover just a material sample, or the recovery and return systems under relevant conditions? A component result alone cannot establish plant self-sufficiency.
Neutrons transfer energy to the blanket. A coolant removes heat. A future plant would connect useful heat to a power-conversion system; heat removal itself does not demonstrate net electrical output.
Evidence to ask for: At what operating conditions was heat removal demonstrated? Does the stated result include conversion and the plant’s own power demand?
Limit radiation and nuclear heating beyond the blanket.
The system also protects structures and magnets. In ITER’s test blanket systems, a shield sits behind the test module. Breeder, coolant, shielding and supporting structures are related parts of an assembly.
Evidence to ask for: What exposure and operating duration does the result cover? How does that compare with the service life being claimed?
A future power plant must integrate the three functions and supporting systems. This map explains that requirement; it does not certify a particular design.
Design milestone
Four preliminary reviews
On 14 September 2026, ITER reported that four breeding concepts had passed preliminary design reviews that summer. It described fusion testing as planned work in its first D–T phase.
Next evidence
From review to operation
Engineering review, component measurements and an integrated operating system answer different questions. Our question is which conditions and interfaces each result actually covers.
Its standard blanket collects heat and provides shielding. Specialised test modules will investigate breeding. ITER’s main heat is sent to heat rejection; future power plants would need a power-conversion cycle. This diagram does not label the whole ITER blanket as a breeding blanket.
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