Neutron Heat & Blanket Cooling

The 5.44% neutron fraction deposits energy in surrounding structure and must be cooled, but this small load is carried by closed loops without evaporation.

The one heat load direct conversion cannot avoid

Direct energy conversion captures charged particles, but neutrons are uncharged and cannot be decelerated by an electric field. In the D-3He burner the neutron fraction is 5.44% of fusion power. Those neutrons escape the plasma and deposit their energy as heat in the surrounding structure, which must be cooled.

How the neutron heat is handled

• Structure surrounding the plasma absorbs neutron energy as heat
• A closed coolant loop removes that heat
• The loop rejects to air, so no water is consumed by the process

Why 5.44% keeps the water story intact

Because only 5.44% of fusion power is carried by neutrons, and because the charged-particle energy is captured directly rather than thermalized, the total heat that must be rejected is small compared with a steam plant's full rejected load. A small load can be rejected to air with a small penalty, so it does not reintroduce evaporative cooling.

Honest framing

This is the burner's irreducible thermal load, and the water story does not pretend otherwise. The point is one of scale: a few percent of fusion power as neutron heat is a manageable, dry-coolable load, not a steam-plant-sized rejection that would demand a cooling tower.