The Divertor

The divertor is the plasma's exhaust system, handling immense heat flux. Kronos relies on detachment and Super-X flux expansion — a stated open item.

Job

Exhaust heat and helium 'ash' from the plasma

Challenge

Heat flux rivaling a rocket nozzle

Kronos approach

Detachment at f_rad ≈ 0.998, Super-X expansion

Status

Beyond current operating precedent (open item)

The divertor is a fusion reactor's exhaust system: a specially shaped region at the bottom of the plasma where field lines are directed to carry away heat and the helium "ash" left over from fusion. It faces some of the highest sustained heat fluxes in any engineered system — comparable to a rocket nozzle.

Kronos manages this through detachment — radiating away most of the exhaust power before it reaches the target — at a radiated fraction f_rad ≈ 0.998, aided by a Super-X magnetic geometry that spreads the heat over a larger area. The design series is candid that this is demanding: the detachment window sits beyond current operating precedent, and its viability is one of the plant's ranked open items.