KRONOS FUSION ENERGYWHITEPAPER LIBRARY
Design & Physics Series · 104 papers

The Kronos Whitepaper Library

A library of short papers on the Kronos design and its low-neutron fuel cycle — the Hyperion breeder, the Aegis and MetroVolt burner, and the method that ties them together. Every paper leads with the physics, names its gates, and traces to deposited data and code. No economics, no forecasts — design and low-neutron, on the record.

Hyperion — The Breeder

  1. 001The Machine That Fathers the Sun-Fuel: Why Kronos Builds the Breeder FirstEvery fusion economy needs a fuel supply before it needs a power plant. Hyperion is the fuel supply.
  2. 002Small by Geometry: The Aspect-Ratio-2.5 Spherical TokamakA fatter torus wins more plasma pressure from every tesla — that is the whole compactness case.
  3. 003Solved, Not Scaled: Where Q = 3.424 Actually Comes FromThe most important thing about Hyperion's gain is how it was obtained, not how large it is.
  4. 004The Breeder's Design Point, on One CardOne operating point, every subsystem checked against the same numbers.
  5. 0059.86 Million Amps: Current as a Buildability ChoicePlasma current is the hardest engineering bill in a tokamak, and Hyperion's is set by its compact geometry.
  6. 006Denser Than SPARC: Heating Power Density as the Real MetricHow hard a fusion core works is measured per cubic metre, and Hyperion works hard.
  7. 007No Heroics Required: Confinement at H98 = 1.0Hyperion's gain does not depend on beating the confinement scaling law — only on meeting it.
  8. 008Breeding Ratio Is a Lever, Not a ConstantHow much tritium Hyperion makes per tritium burned is a design choice, and the design chose 1.8.
  9. 009Three Products From One Plasma: Tritium, Helium-3, NeutronsHyperion is a foundry, not a generator — and it makes three materials the United States cannot source at scale.
  10. 010The 14 MeV Neutron a Mirror Cannot MakeMaterials qualification needs fusion-spectrum neutrons, and only the D-T breeder produces them at rate.
  11. 011Sized to the Requirement: Tritium at 1.87-4.0 kg/yrHyperion is built to a stated national tritium need, not to whatever a physics optimum happens to yield.
  12. 012How a Tritium Machine Makes Helium-3The burner's scarce fuel is a free decay product of the breeder's primary output.
  13. 013Declaring the Ash: Why f_He4 = 0.05 Is Printed, Not BuriedThe number under the gain is the helium ash fraction — and Kronos writes it down.
  14. 014Capacity Factor: Damage-Life-Limited, Not Duty-LimitedHyperion runs steady-state, so its uptime is set by how long the first wall survives, not by a pulse cycle.
  15. 015A Four-Year Build, by PrecedentHyperion's schedule is anchored to a real compact-HTS device, not to an aspiration.
  16. 016Fuel Follows Purpose: Why the Breeder Burns D-THyperion and the burners run different fuels on purpose — each fuel chosen for what the machine must do.
  17. 017Inside Existing Practice: Hyperion's Tritium InventoryThe breeder's radiological posture is bounded by design to stay inside civil licensing practice.
  18. 018Gain Only: The Milestone Hyperion Does Not Need to ClearThe breeder is buildable because it is excused from the hardest bar in fusion — net electricity.
  19. 019HTS Magnets for a Compact CoreHigh-temperature superconducting tape is what lets a 1.2-metre machine reach reactor conditions.
  20. 020Designing to a Requirement, Not an OptimumThe most consequential choice in Hyperion is a philosophy: build what is needed, not what is maximal.

The Burner — Aegis & MetroVolt

  1. 021One Generator, Two Housings: Aegis and MetroVoltAegis and MetroVolt are the same D-3He mirror in two markets — not two machines.
  2. 022Open Field Lines: Why the Burner Is a MirrorThe burner's signature move is to let the plasma leak — on purpose, into a converter.
  3. 023The Locked Mode M Closing Point: Q_E 1.31, On One Hard RequirementThe burner has a reproducible closing point — contingent on an end-plug density that is specified, not yet demonstrated.
  4. 024The One Number That Decides Closure: Plug Density RatioNot field, not size, not fuel mix — the burner's fate rests on the end-plug density ratio.
  5. 025Length Sets Size, Not ClosureThe mirror's central-cell length is a free knob — it changes power and footprint, not whether the machine works.
  6. 026Aegis: The Defense Housing of the BurnerAegis is the defense configuration — resilient, fuel-logistics-free power for fixed installations.
  7. 027MetroVolt: The Data-Center Housing of the BurnerMetroVolt is the commercial configuration — firm, carbon-free campus power with no steam cycle and no long-lived waste.
  8. 028Fixed Site, Not Shipboard: A Computed Negative Kept in the OpenThe naval-propulsion version of Aegis does not fit in a hull — and Kronos published the reason.
  9. 029A Generator on 1.66 AcresThe burner's folded footprint is small enough to site where power is actually needed.
  10. 03017 Tesla, Already Built: The Mirror Throat FieldThe burner's high-field magnets sit on a demonstrated number, not an extrapolated one.
  11. 031Beta 0.55, Inside What GDT MeasuredThe burner runs at a plasma pressure fraction experiments have already reached.
  12. 032The Mirror-Ratio Penalty, Settled: 1.21x, Not 3.3xA worry that the burner's confinement carried a hidden penalty turned out to be overstated by design.
  13. 033How a Mirror Holds Plasma: Pastukhov and the Confining PotentialThe burner's confinement is electrostatic — a potential hill the plasma must climb to escape.
  14. 034Solved, Not Assumed: The Electron TemperatureThe burner's electron temperature is an output of the power balance, and it is not equal to the ion temperature.
  15. 035The Charged-Power Budget: Why Open Systems Are DifferentA mirror must pay its end losses out of charged power — and that single fact governs the burner.
  16. 036Why Pure Deuterium Does Not Close in a MirrorDeuterium-only fuel has better mirror confinement than D-3He — and still cannot close. Here is why.
  17. 037The Closure Window: Helium-3 Fraction 0.20 to 0.43There is a fuel-mix window in which the burner closes — bounded on both sides, and published.
  18. 038The Fuel Mix Is a Neutron Knob — and the Machine Gets Cleaner With TimeRaising the helium-3 fraction cuts neutron output ~4x across the closure window — and one step is free in gain.
  19. 039An Interior Optimum: Ion Temperature at 80-100 keVThe burner's ion temperature has a real peak, not a monotone trend — and the design sits on it.
  20. 040Wide in Nine of Ten Parameters — and That Is the ProblemThe burner is not a knife-edge. Its trouble is the opposite: most knobs barely matter.
  21. 041Unchannelled on Purpose: No Speculative Physics in the BaselineThe burner's baseline assumes zero alpha channelling — because no one has ever measured it.
  22. 042A Reproducible Closing Point, and the One Requirement It Rests OnThe burner has a locked, reproducible closing point (Q_E 1.31) — honest that its closure is a requirement, not yet demonstrated.

Low-Neutron by Design

  1. 043Low-Neutron, Never Aneutronic: A Few Percent Is Small and It Is Not ZeroThe burner's fuel is quiet, not silent — and the language stays honest about the difference.
  2. 044The Neutron Fraction Is Not a Fuel ConstantHow neutronic the burner is depends on how well it confines — a coupling most models miss entirely.
  3. 045The Coupling Nobody Models: Better Confinement, More NeutronsImproving the plasma's confinement raises its neutron output — a trade the design has to hold in view.
  4. 046The Gentle Wall: Far Below the Breeder's Neutron LoadA low-neutron fuel gives the burner a first wall that is comfortable, not consumable.
  5. 047D-3He Versus D-T: The Neutron Budget ComparedChoosing the fuel is choosing the plant you must build around it — and the neutron budget is the fork.
  6. 048Tuning the Neutron Output From the Fuel LineThe burner's neutron production is set decades in advance, at the fuel mix — and it is adjustable.
  7. 049The Secondary Burn: Where the Burner's Neutrons Come FromThe burner breeds a little tritium and burns 17% of it — and that secondary D-T is a real neutron source.
  8. 050No Breeding Blanket: The Component the Burner DeletesBecause the burner does not run on tritium, it needs no blanket to breed it — and that removes a whole plant.
  9. 051Quiet Structures: Activation and the Low-Level-Waste PathFewer neutrons means less activated steel — and a decommissioning stream that fits existing disposal.
  10. 052Designed to Die of Old Age: Materials Dose Over Plant LifeThe burner's wall is engineered to reach the end of the plant's life, not to be swapped on a cycle.
  11. 053Two Neutrons, Two Purposes: 2.45 MeV Versus 14 MeVThe burner's neutrons are the wrong energy for materials testing — on purpose. That job belongs to the breeder.
  12. 054The Breeder Is Neutron-Rich on PurposeOne machine in the family wants neutrons — and designs to make them at full rate.
  13. 055Tritium-Lean by Design: A Trace Species in the BurnerThe isotope that dominates fusion licensing is only a fleeting trace in the burner.
  14. 056Shielding a Quiet MachineFewer neutrons means thinner shields, lighter structures, and more of the machine doing useful work.
  15. 057The Maintenance Dividend of Low NeutronsThe quiet fuel's biggest payoff is not physics — it is the outages that never have to happen.
  16. 058Neutron Provenance: Every Channel Computed From Cross SectionsThe burner's neutron budget is not a literal in a file — it is derived, channel by channel.

Direct Energy Conversion & Power Handling

  1. 059Electricity Without the Steam DetourWhen fusion energy arrives as charged particles, you can collect it like electricity — because it already is.
  2. 060The Expander: Turning a Beam Into a Collectible SheetBefore the burner can convert its exhaust, it has to spread it out — that is what the expander does.
  3. 061The Number That Feeds the Converter: Directed Fraction 0.648How much of the burner's power arrives as collectible directed energy is a computed value — with synchrotron charged.
  4. 0620.871 Is a Ceiling, Not a Design ValueA flattering directed-fraction number exists in the record — and the design refuses to use it.
  5. 063Handling the Heat: 3.7 MW/m2 on the End WallThe burner's exhaust has to land somewhere — and where it lands is engineered to survive it.
  6. 064Electron Direct Conversion: A Named Gate, Not an AssumptionOne of the two things standing between the burner and net electricity is a converter that must be demonstrated.
  7. 065The Dominant Loss: Synchrotron Radiation at Half the Fusion PowerThe single largest energy loss in the burner is not the end leak — it is the light the electrons emit.
  8. 066Bracketing the Uncertainty: Trubnikov, AFJ, and the Optically-Thin BoundThe burner does not trust one synchrotron formula — it publishes the whole bracket, including the one that fails.
  9. 067Survival by Reabsorption: The Burner's Most Consequential AssumptionThe design closes only because the plasma reabsorbs most of its own synchrotron light — and that fraction is unmeasured.
  10. 068Bremsstrahlung, Cross-CheckedThe burner's second radiation channel is computed two ways, and the design uses the more cautious one.
  11. 069Recirculating Power: What the Plug Costs the PlantThe burner spends a large fraction of its own output keeping the plug alive — and that spend is the ledger's crux.
  12. 070Converter Efficiency in the WindowThe direct converter's efficiency matters — but not as much as the one parameter that actually decides closure.
  13. 071Diversified Power Handling: Directed, Radiated, and ResidualThe burner does not rely on a single conversion path — it collects power in several complementary ways.
  14. 072Honest Lower Bounds: The Energy Convention the Ledger UsesWhere the physics was ambiguous, the burner chose the convention that understates its own output.

The Fuel Cycle — Tritium & Helium-3

  1. 073Fuel Follows Purpose, Not PlatformThe whole family's fuel logic reduces to one rule — and the fuel cycle is where it plays out.
  2. 074Helium-3: The Burner's Fuel, the Breeder's Co-ProductThe scarcest input in the family is made by one member and consumed by the others.
  3. 075The Burner's Helium-3 AppetiteThe burners' demand for helium-3 is large enough to be the enabling condition of the whole product line.
  4. 076The External Gate: Lunar Helium-3The commercial burner fleet's largest dependency is not physics at all — it is where the fuel comes from.
  5. 077Stockpile That Ripens: Tritium Decay to Helium-3Every gram of tritium is a slow helium-3 factory — and the rate is a known physical constant.
  6. 078Breeding Fuel in the Burner: The D-D Helium-3 ChannelThe burner makes a little of its own helium-3 as it runs — a partial, honestly-bounded credit.
  7. 079Breeding at 1.8: How Hyperion Makes More Than It BurnsThe breeder's surplus tritium is the whole point — and the breeding ratio is a design lever set to 1.8.
  8. 080Tritium to the National RequirementThe breeder's primary product answers a supply gap the United States cannot currently fill at scale.
  9. 081Tritium-Lean: The Burner's Fuel-Cycle DisciplineThe burner holds almost no tritium — a fuel-cycle property, not a safety add-on.
  10. 082Carried at Zero: The Unpriced Neutron StreamOne of the breeder's products has no market price anywhere in the world — so the programme books it at zero.
  11. 083Sequencing the Fuel: A Breeder Decade Feeds the DemonstratorThe programme's order is a fuel-supply argument — make the fuel first, burn it later.
  12. 084A Self-Fuelled Demonstrator: ~10 MWe on the Breeder's Decay Helium-3The first burner is a ~10 MWe Aegis demonstrator, sized to the helium-3 the breeder's own tritium decays into.

Method, Safety & Trust

  1. 085The Fusion Company That Shows Its WorkKronos's differentiator is not a claim about performance — it is a commitment to candor.
  2. 086Frozen Points and Recorded WithdrawalsA frozen number at Kronos is a commitment against silent change — not a claim of final truth.
  3. 087Reproduced From Source: Eleven of Eleven ChecksBefore a number is frozen, it is re-derived from its origin — and the re-derivation is logged.
  4. 088Bit-Exact: Verifying Against the Prior EvaluatorWhen the burner's new solver replaced the old one, it first reproduced the old one exactly — then corrected it.
  5. 089Declared Basis Over Silent BasisThe recurring lesson in the Kronos record is not about arithmetic — it is about stating your assumptions.
  6. 090Named Gates, Not Hidden AssumptionsEvery Kronos machine states the specific things that must be demonstrated before it works.
  7. 091Labeled History: Superseded Values Are Kept, Not DeletedWhen a Kronos number changes, the old one stays in the record with an era label — on purpose.
  8. 092Deterministic by Construction: No Randomness in the AnswerThe burner's design point is a solve on a fixed grid — run it again and you get the same number.
  9. 093Naming the Largest Open ItemThe burner's design record points directly at its own biggest weakness — and calls it the next track's job.
  10. 094Cross-Checks From Independent PhysicsThe burner's headline gain is trusted because a different method reached nearly the same number.
  11. 095Read the Limitations FirstThe burner's design record asks you to read its caveats before quoting anything above them.
  12. 096Safety Posture: A Trace Source Term and No RepositoryThe burner's low-neutron fuel makes its safety case categorically different from a D-T plant's.
  13. 097Licensing Posture of a Low-Neutron PlantThe burner's biggest schedule advantage may be regulatory, and it comes straight from the fuel choice.
  14. 098An Experiment, Not a Power Plant: The Founder's BaselineThe phrase that governs every Kronos claim is a refusal to call an experiment a power plant.
  15. 099Sensitivity Published, Not BuriedKronos ranks its parameters by how much they matter — and publishes the ranking, inconvenient entries included.
  16. 100Open Deposit: Data and Code, Not Just ClaimsEvery headline number in the Kronos record traces to deposited data and runnable code.

The Mode D2/M Evolution — Cleaner and More Durable

  1. 101Breeder Physics Closed; Burner Closing Point Locked on One RequirementThe breeder's power balance is closed and reproduces; the burner has a reproducible closing point contingent on a single named requirement.
  2. 102Public Dose Closes, With Room to SpareThe offsite dose requirement is met by an ordinary detritiation system, far inside demonstrated practice.
  3. 103The Burner's Scheduled-Replacement Waste Is Essentially ZeroA first wall that lasts a century of full-power operation is a first wall you almost never replace.
  4. 104Why Not Fully Aneutronic: The x >= 0.45 RedesignThe burner could be made far cleaner — but true near-aneutronic operation is a different machine, and the record says so.
Conceptual design and simulation study; no machine has been built. Values are simulation-derived and carry the feasibility gates named in each paper; superseded values are kept in the record with era labels. Informational only; not an offer of securities. © 2026 Kronos Fusion Energy, Inc. · Los Angeles, California.