Superconducting Magnet Safety
The magnets store large energy and operate at high field and low temperature; their hazards are engineered, not radiological.
The magnets that confine the plasma are among the most safety-relevant systems in a fusion machine — not because of radiation, but because they store large electromagnetic energy at high field and cryogenic temperature. The breeder (Hyperion) reaches a peak field of 16.84 T (about 8 T on axis); the burner (Aegis / MetroVolt) reaches 26.49 T at its plugs and 17 T at the throat.
The three magnet hazards
- Stored energy: a large magnetic energy that must be removed safely on a fault.
- Quench: a superconductor losing superconductivity, converting stored energy to heat.
- Cryogenics: very low temperatures and the risk of rapid helium boil-off.
Each hazard has a dedicated engineered response: quench detection and protection that senses a normal zone and triggers a controlled energy dump; structural coil cases that contain the mechanical forces; and cryogenic safety systems that manage pressure and oxygen displacement. None of these hazards can cause a radiological release.
Independent from the reaction
Importantly, magnet safety is decoupled from fuel safety. A magnet fault ends confinement, which ends the fusion reaction — the plasma simply terminates. The magnet-protection systems then manage the electromagnetic and cryogenic energy on their own timescales. The two hazards do not compound into a larger event.
Magnet safety is a high-power electrical and cryogenic engineering discipline with decades of precedent in large superconducting systems.