Magnetic Field Worker Safety
Static magnetic fields are managed with exposure zoning, implant screening, and projectile control — established strong-magnet practice.
Working around very strong magnets carries physical, non-radiological hazards. The static fields — up to 16.84 T peak in the breeder and 26.49 T at the burner's plugs — exert forces on ferromagnetic objects and can interact with certain medical implants. Worker safety is managed with the same discipline used around high-field research magnets and MRI systems.
The controls
- Exposure zoning: access staged by field strength, with clear signage at contours.
- Implant screening: personnel with sensitive medical devices screened before entry.
- Projectile control: ferromagnetic tools and objects excluded from field zones.
- Non-magnetic tooling: maintenance uses non-ferromagnetic equipment in field areas.
- De-energized maintenance: most in-field work occurs with magnets off.
Direct human exposure to static magnetic fields is governed by occupational exposure guidance; brief exposure to strong fields is managed by limiting time and movement in high-gradient regions, where rapid motion can cause transient sensations. The controls are precautionary and well established — nothing here is unique to fusion beyond the field strength.
Only while energized
All field-zone controls apply only while the magnets are energized. Maintenance is performed with the coils de-energized under protected sequences, at which point the projectile and implant precautions lift. This separates magnetic-field worker safety cleanly from the radiological controls, which follow shutdown activation instead. See high-field safety zones.
Strong-magnet worker safety is a known, bounded discipline applied at Kronos field levels.