Fusion Neutronics

Neutronics is the study of how fusion neutrons travel, deposit energy, and activate materials. For a low-neutron plant, the numbers are far gentler.

What

Transport of neutrons through reactor materials

Concerns

Heating, damage (dpa), activation, shielding

Kronos neutron fraction

~5.25% (low-neutron)

High-fidelity check

OpenMC (S63, planned)

Fusion neutronics is the discipline of tracking where a reactor's neutrons go: how they scatter and slow through the wall and shield, how much heat and radiation damage (measured in displacements per atom, dpa) they deposit, and how much they activate the structure. It sets the shield thickness, the component lifetimes, and the waste profile.

For Kronos MetroVolt the neutronics is unusually gentle by fusion standards, because the low-neutron D–³He fuel produces a neutron fraction around 5.25% — roughly 25× below D–T. The design carries an explicit neutron-fluence budget for the shielded center stack, and a high-fidelity OpenMC neutronics calculation (S63) is planned to fix the true shield and lifetime numbers.