Plasma-Facing Component Cooling

The surfaces that face the plasma and the end regions that receive escaping particles carry heat flux that must be removed by closed coolant channels.

The heat-flux challenge

In any fusion device the components nearest the plasma receive concentrated heat and particle flux. In the tandem-mirror burner this includes the first-wall surfaces and the end regions where charged particles stream toward the direct converter. These surfaces must be actively cooled to stay within material limits.

How it is cooled

• Coolant channels embedded in or behind the plasma-facing surfaces
• A closed loop carries absorbed heat to a heat exchanger
• Rejection to air keeps the loop's water inventory sealed and unconsumed

This is a high-flux but comparatively low-total-power load. It is demanding on materials and channel design, but its total heat is modest next to a steam plant's condenser load, so it does not require evaporative cooling.

Relationship to direct conversion

Some of the energy reaching the end regions is captured by the direct converter as electricity rather than lost as heat. Efficient collection reduces the heat that the plasma-facing and converter surfaces must shed, which further shrinks the cooling load and the water it might otherwise imply.

Honest scope

Material selection and channel geometry for these components are active simulation and design questions. What the water story asserts is narrow: whatever the final design, this load is small enough to be carried by closed loops with dry rejection, so it does not reintroduce steam-cycle water consumption.