Magnet Cryogenics

REBCO magnets must be held superconducting at cryogenic temperature; the cryogenic system removes heat leaks and neutron-deposited power from the coils.

Keeping the magnets cold

Superconductivity only exists below a critical temperature, so Hyperion's REBCO coils must be held cold and stable throughout operation. The cryogenic system cools the magnets, maintains them against heat leaking in from the surroundings and power deposited by neutrons and radiation, and keeps every part of the winding within the temperature and strain window where it stays superconducting.

REBCO's advantage

REBCO's higher operating temperature relative to low-temperature superconductors eases the cryogenic burden: the plant does not have to reach the very lowest temperatures required by older conductors. That reduces cryogenic power and gives more thermal headroom against transient heat loads. It is one of the practical reasons the high-temperature-superconductor choice suits a compact, high-field machine.

Neutron heating and stability

Even shielded, the magnets absorb some neutron and gamma energy, which appears as heat the cryogenic system must remove, and this load is worst near the lightly shielded center stack. If any part of the coil warms past its temperature limit it can lose superconductivity locally and quench, so the cryogenic and quench-protection systems work together. Sizing the cryoplant for steady loads plus fault transients is part of the machine's integrated design.

• Holds REBCO coils below their critical temperature
• REBCO's higher operating temperature eases the plant
• Must remove neutron-deposited heat and prevent quench

This page describes a design and simulation study, not a built machine. Construction begins Q2 2027; first-of-a-kind first tritium is targeted near 2030.