What this document is, and how to read its numbers
This is a combined editorial. It gathers, in one volume, the two design studies Kronos Fusion Energy released in 2026 — a compact spherical-tokamak tritium/helium-3 breeder and a deuterium–helium-3 tandem-mirror generator — together with the intellectual-property estate, the people, and, in the internal edition, the full commercial case. The scientific text is the same text that appears in the arXiv preprints and the journal submissions; the editorial adds the apparatus a reader needs to hold the whole program at once, and nothing in the physics is altered to fit it.
The honesty stance is the asset
Every headline quantity carries an evidence class — Derived Recomputed Measured Requirement — and, where a number is a modelled extrapolation rather than a demonstrated value, it is labelled as such and its downside is shown next to it. Several quantities in the underlying corpus moved after first publication; where a value has been withdrawn or restated, the record says so plainly. This is deliberate: a diligence team will find the load-bearing assumptions, so the document surfaces them first.
- Title
- The Kronos Fleet — Hyperion · Aegis · MetroVolt: A Combined Design & Commercialization Study
- Author
- Priyanca Ford, Founder & CEO, on behalf of Kronos Fusion Energy
- Edition
- 2026 Combined Editorial · first issue
- Companion works
- The five-paper arXiv drop — (1) Breeder, (2) Burner, (3) REBCO magnet & tape, (4) Direct Energy Conversion, (5) AI/ML/Quantum control — with matching numbered Zenodo deposits, plus the IOP journal and IAEA-FEC submissions. Patents were filed before the drop.
- Naming
- Hyperion = the breeder; Aegis (defense) and MetroVolt (data-center) = one generator in two housings. Internal mode letters (D1, L) do not appear on public surfaces.
- Status
- Conceptual design & simulation study. Nothing herein is a construction commitment.
The fleet at a glance, and the way its numbers are marked
This volume opens with Orientation, presents the five research papers as a bound sequence, and closes with the Apparatus. Foundations sets out the three general results both machines rest on. Paper One is the Hyperion breeder; Paper Two the Aegis / MetroVolt generator; Papers Three, Four and Five are the enabling science — high-field REBCO magnets and tape, direct energy conversion, and the AI / ML / quantum control stack. A Digital Twin & 3-D Model part follows, then the Environmental profile. The Economics and levelized cost and the Business Case and diligence record appear in the internal edition only; the Simulations proof record and the Apparatus — patent portfolio, team, limitations, and sources — close both editions.
The fleet at a glance
| Hyperion | Aegis | MetroVolt | |
|---|---|---|---|
| Role | Strategic-isotope foundry | Defense installation power | Campus power |
| Machine | Spherical tokamak | Tandem mirror | Tandem mirror |
| Fuel | Deuterium–tritium | Deuterium–helium-3 | Deuterium–helium-3 |
| Delivers | Tritium · ³He · 14 MeV n | Resilient installation power | Firm campus power |
| Physics bar | Fusion gain only | Closure (gates named) | Closure + lunar ³He |
| In the fleet | Breeds the fuel | Proves the generator | Commercial destination |
How the numbers are marked
Every headline quantity carries an evidence class — Derived from first principles, Recomputed from raw data, Measured in hardware, or a Requirement yet to be met. Financial figures carry a case label and are confined to the internal (confidential) edition. Values that moved after first publication are shown as withdrawn or restated rather than quietly changed. A capability you can evaluate is one whose limits are on the page.
The Tritium Fuel Cycle — A Breeding Ladder, Not a Number
A breeder’s product is tritium, and its credibility rests on an honest mass balance. The per-unit burn rate is fixed by the fusion power at 4.76 kg-T per full-power-year, and the net surplus is a confirmed ladder: net TBR ~1.06 (literal recipe), ~1.19 (solid-beryllium layer), and 1.42 (advanced blanket, ~2.0 kg-T/yr per unit) — the last the confirmed per-unit ceiling, above which the spherical-tokamak centrepost caps the inboard coverage. A single advanced unit is a tritium exporter; a national-scale 4 kg-T/yr supply is a fleet property, never a single-unit claim.
Companion deposit (code & data, reproducible under CC BY 4.0): DOI 10.5281/zenodo.22132123 (v2 10.5281/zenodo.21795620) · Zenodo community kronos_fusion_energy.
Explore it live: interactive 3-D model · run the physics validator · companion film series (the deposited solvers, in the browser).
Table of Contents
Symbols, units, and the names of things
A breeder is only as credible as its mass balance
A fusion breeder’s product is tritium, and the temptation, historically, has been to quote a single flattering breeding ratio and move on. We do the opposite. We develop the tritium fuel cycle as a confirmed ladder of design points, derive the burn rate from first principles, and separate what a single unit delivers from what a fleet delivers — because conflating the two is how prior breeder concepts overstated themselves.
A single advanced unit is a tritium exporter at the ~2.0 kg-T yr−1 scale. A national-scale 4 kg-T yr−1 supply is a fleet property — never a single-unit claim, because the spherical-tokamak centrepost caps the per-unit ceiling at net TBR 1.42.
The burn rate, and the surplus
Each 17.59 MeV deuterium–tritium fusion consumes one triton, so the per-unit burn rate follows directly from the fusion power: ΛT = 4.76 kg-T per full-power-year at 85.04 MW. The net surplus available for export is then S = (TBR − 1) ΛT. The breeding ratio, not the burn rate, is therefore the design lever — and it is a lever, not a constant. Derived from Pfus
The breeding ladder
Three-dimensional OpenMC neutronics on ENDF/B-VIII.0 place the ladder. The literal frozen recipe gives net TBR ~1.06 and a surplus of 0.29 kg-T yr−1; a dedicated 5 cm solid-beryllium multiplier raises it to ~1.19 and 0.9; and the advanced blanket — a void-reduced breeder with a solid-beryllium multiplier and a steel reflector — reaches net TBR 1.42 and about 2.0 kg-T yr−1 per unit.
This TBR 1.42 is the confirmed per-unit ceiling across twelve blanket configurations; a lithium–lead alternative was explored and does not beat it, and the result reproduces across an independent nuclear-data evaluation to under 0.3%. Cross-library reproduced
Per unit versus fleet
The distinction is load-bearing. A single advanced unit exports tritium at the ~2.0 kg-T yr−1 scale. A national-scale 4 kg-T yr−1 supply is reached by two advanced units, or four-to-five solid-beryllium units — and the co-produced helium-3 aggregates the same way, to 3.6-4.5 kg yr−1 across the fleet. We never claim 4 kg-T yr−1 from one unit.
The closed loop
The fuel cycle closes through direct internal recycling of unburned tritium from the exhaust, blanket tritium extraction, detritiation of process streams, and permeation control at the blanket–coolant boundary. Direct internal recycling minimizes the standing inventory — and the standing inventory, not the breeding ratio, is what the safety case turns on — by returning unburned fuel promptly rather than through a large buffered store.
Helium-3, bred by the decay of surplus tritium at equilibrium, is a co-product of that inventory rather than an independent channel. The standing-inventory value that sets the accident source term is computed in the fuel-cycle model and carried to the safety companion — flagged as the governing safety quantity, not asserted here. Computed downstream
The patent portfolio
The estate spans a granted high-field magnet patent, pending utility and 2026 provisional filings that map to the two products, a digital-twin control provisional, a registered trademark application, and the original 2022 provisional family. Every patentable disclosure in the five-paper arXiv drop was protected before publication: the breeder and burner provisionals were filed 1–2 August, and a publication-gap omnibus filing the evening before the drop swept up the DEC, plasma-control, and REBCO-winding matter of the three otherwise-unprotected papers. Patent numbers and application serials are matters of public record; claim scope is summarised, not reproduced.
Granted & pending utility
2026 provisional filings — mapped to the products
Trademark & origin
The narrow, defensible magnet novelty — the specific conductor and the digital-twin winding optimisation, not high-field REBCO as a category — is the commercial core that can earn ahead of any Q > 1 milestone, with markets in fusion magnet supply, MRI/NMR, accelerators, and proton therapy. The claim is scoped honestly: the high field is a system field result, not a stand-alone-coil record; the small-bore plug coil is structurally infeasible as a bare winding but resolved by a stress-managed structural shield (feasible-pending-FEA); and the winding-tape experiment returned a null result. The value is the method, not a field record.
Founding partners, board, advisors & auditors
Kronos is built by a bench of advanced-fuel-fusion, high-field-magnet, direct-conversion, and materials specialists, with a board and operations team drawn from defense, national laboratories, and industry. Dates are shown as ranges; where a tenure has ended or is term-ending, the range says so.
Founding Partners — Science
Board
Scientific Advisors
Scientific Auditors
Operations
Legal counsel is retained; those roles are held on the internal roster and are not listed here.
List of Figures
Sources
[1] H.-S. Bosch and G. M. Hale, “Improved formulas for fusion cross-sections and thermal reactivities,” Nuclear Fusion 32, 611 (1992).
[2] A. S. Richardson, NRL Plasma Formulary, Naval Research Laboratory (2019).
[3] I. E. Ochs, E. J. Kolmes, and N. J. Fisch, “Bremsstrahlung and the electron–electron contribution in fusion plasmas,” Physics of Plasmas (2024).
[4] T. H. Rider, “Fundamental limitations on plasma fusion systems not in thermodynamic equilibrium,” Physics of Plasmas 4, 1039 (1997).
[5] ITER Physics Expert Groups, “ITER Physics Basis,” Nuclear Fusion 39, 2137 (1999).
[6] N. A. Uckan and J. Sheffield, “Tokamak scaling and confinement,” in Tokamak Concept Improvement, IAEA (1989).
[7] O. Sauter, C. Angioni, and Y. R. Lin-Liu, “Neoclassical conductivity and bootstrap current,” Physics of Plasmas 6, 2834 (1999).
[8] F. Troyon et al., “MHD limits to plasma confinement,” Plasma Physics and Controlled Fusion 26, 209 (1984).
[9] J. P. Freidberg, Plasma Physics and Fusion Energy, Cambridge University Press (2007).
[10] R. F. Post, “The magnetic mirror approach to fusion,” Nuclear Fusion 27, 1579 (1987).
[11] D. E. Baldwin, “End-loss processes from mirror machines,” Reviews of Modern Physics 49, 317 (1977).
[12] T. K. Fowler, R. W. Moir, and T. C. Simonen, “A new simpler tandem mirror,” Nuclear Fusion 57, 056014 (2017).
[13] G. L. Kulcinski and J. F. Santarius, “Advanced fuels and the D–3He cycle,” University of Wisconsin Fusion Technology Institute.
[14] W. L. Barr and R. W. Moir, “Test results on direct energy converters for mirror reactors,” Nuclear Technology/Fusion 3, 98 (1983).
[15] D. B. Go et al., “Thermionic energy conversion in the twenty-first century,” Frontiers in Mechanical Engineering 3, 13 (2017).
[16] M. Wang et al., “The AME 2020 atomic mass evaluation,” Chinese Physics C 45, 030003 (2021).
[17] J. E. Menard et al., “Fusion nuclear science facilities and pilot plants based on the spherical tokamak,” Nuclear Fusion 56, 106023 (2016).
[18] A. J. Creely et al., “Overview of the SPARC tokamak,” Journal of Plasma Physics 86, 865860502 (2020).
[19] T. P. Wright, “Factors affecting the cost of airplanes,” Journal of the Aeronautical Sciences 3, 122 (1936).
[20] U.S. Department of Energy / NNSA, Stockpile Stewardship and Management Plan, FY2024.
[21] J. F. Santarius, G. L. Kulcinski, and L. A. El-Guebaly, “A strategy for D–3He fusion energy development,” Journal of Fusion Energy 17, 33 (1998).
[22] M. A. Abdou et al., APEX advanced blanket concepts, Fusion Engineering and Design (1999–2003).
[23] Federal Register, notice on supply of tritium to non-federal entities (1999).
[24] Kronos Fusion Energy, “Simulation register and reproducibility deposit,” Zenodo (2026).
[25] A. O. Thome et al., “ELM-free negative-triangularity edge on DIII-D,” Plasma Physics and Controlled Fusion (2024), doi:10.1088/1361-6587/ad6f40.
[26] T. Eich et al., “Scaling of the tokamak near scrape-off layer power width,” Nuclear Fusion 53, 093031 (2013).
[27] J. Lim et al., “Scrape-off-layer width in negative-triangularity plasmas,” Nuclear Fusion / Plasma Physics and Controlled Fusion (2023).
[28] A. O. Nelson et al., “Prohibition of second-stability access at negative triangularity,” Plasma Physics and Controlled Fusion 64, 124002 (2022).
How this document was made
The Kronos Fleet — Combined Editorial, 2026 is set in Fraunces (display), Gelasio (text), and IBM Plex Mono (data & equations), carried forward from the Kronos editorial design system.
The figures are rendered at 300 dpi from the deposited generator scripts; the document is composed as a single self-contained file with embedded fonts and imagery, paginated to US Letter, and rendered to PDF through a headless Chromium engine in matched light and dark editions.
Every headline quantity carries an evidence class; withdrawn and restated values are marked as such. Nothing herein is frozen beyond the founder-approved Tier-A set.
Explore it live — turn the interactive 3-D model, run the deposited solvers in the physics validator, and watch the companion film series.
Notice, status, and distribution
Conceptual design & simulation study. This document reports a conceptual design and simulation study. It is not a construction commitment, a safety-analysis report, a regulatory filing, or an offer of securities. Forward-looking statements — schedules, costs, market sizes, and performance — are estimates subject to the limitations set out in the Simulations part and may change.
Numbers and their classes. Quantities are reported with evidence classes and case labels; modelled, assumed, and requirement-class values are identified as such and are not to be quoted without their labels.
Public edition. This edition carries the physics and design only; all financial, funding, and defense-commercial content has been removed for public distribution. The scientific text corresponds to the arXiv and journal submissions.
© 2026 Kronos Fusion Energy. All rights reserved. Hyperion, Aegis, and MetroVolt are product designations of Kronos Fusion Energy.
One programme, in five papers
This editorial is one of five that together describe the Kronos fusion programme — a breeder that funds a generator, and the magnet, conversion, and control science that enable both. Each is published open-access with a reproducible companion deposit.
Explore the whole programme live: the interactive 3-D model, the in-browser physics validator, and the companion film series.