KRONOS FUSION ENERGYWHITEPAPER 052 / 104
Low-Neutron by Design

Designed to Die of Old Age: Materials Dose Over Plant Life

The burner's wall is engineered to reach the end of the plant's life, not to be swapped on a cycle.

Integrated over a plant lifetime, the burner's low neutron load (5.44% at the design point) keeps the accumulated materials dose inside what the structural alloy can tolerate — a frozen first-wall life of 104 to 428 full-power years, against about 2.5 for the breeder. That translates to roughly 0.035 to 0.144 first-wall changes across 30 years: scheduled-replacement waste is essentially zero.

The science

Materials damage accumulates as displacement-per-atom (dpa) from neutron flux. Because the burner's neutron fraction is only 5.44%, its wall load is roughly an order of magnitude below a D-T plant's, giving a frozen first-wall life of 104-428 fpy. The consequence is that the burner's capacity factor is plug-limited, not damage-limited — the opposite of the breeder, and a genuine mirror advantage (B31).

Why it matters

A wall that lasts the plant's life removes the biggest scheduled outage in fusion operations. That is the difference between a plant that spends months per year changing components and one that mostly runs — the availability advantage the low-neutron thesis rests on.

The numbers

Damage metricdisplacement per atom (dpa)
First-wall life104-428 fpy (vs breeder ~2.5)
Neutron fraction5.44% (M-43 restated)
Capacity factorplug-limited, not damage-limited
Scheduled changeoutsnone by design
Straight answersThe first-wall life (104-428 fpy) and the plug-limited CF are frozen (B31); the plug-reliability CF number itself is a standing research ask, not yet pinned. The dose is set by the operating-point neutron budget.
Kronos is the fusion company that shows its work. Every figure here traces to the openly deposited Kronos simulation programme and design-point records (CC BY 4.0). Read the series, run the code, check us. — All whitepapers
Conceptual design and simulation study; no machine has been built. Quantitative values are simulation-derived and carry the feasibility gates named in the text; superseded values are kept in the record with era labels. This document is informational and is not an offer of securities. © 2026 Kronos Fusion Energy, Inc. · Los Angeles, California.
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