Testing Magnet Materials Under Neutrons
High-field superconducting magnets sit near the neutron source; their materials must be qualified against the radiation they will see.
Magnets in the neutron field
The breeder reaches a peak field of 16.84 T, with about 8 T on axis, using high-temperature superconducting magnets. Those magnets, and their insulation and structure, operate near a strong 14 MeV neutron source. Radiation can degrade superconductor performance and, more sensitively, the organic insulation, so these materials need qualification data.
What is tested
- Critical current of the superconductor vs fluence
- Insulation strength and integrity under irradiation
- Structural alloys and joints near the coils
A self-referential service
The breeder both needs this data and can generate it. Its own 14 MeV neutrons are exactly the environment magnet materials must survive, so magnet-material qualification is a natural neutron service, valuable to fusion programs and to any high-field magnet application in a radiation environment.
Reported figures are design-study values for a machine not yet built; construction begins Q2 2027.
Insulation is the sensitive part
In a high-field magnet, the organic insulation is usually more radiation-sensitive than the superconductor itself, so its behavior under neutron exposure often sets the magnet's allowable lifetime. Characterizing insulation, joints, and structure against a 14 MeV spectrum tells designers where to add shielding and how to schedule maintenance. Because the breeder both needs this data and can generate it, magnet-material qualification is a natural, self-consistent neutron service. Qualifying the insulation and structure alongside the conductor gives magnet designers a complete radiation-lifetime picture, which is as relevant to any high-field magnet in a radiation field as it is to the breeder itself.
This page describes a design and simulation study, not a built machine. The breeder (Hyperion) begins construction Q2 2027; first-of-a-kind first tritium is targeted near 2030. No hardware net-gain is claimed before then.