Physical Transformation AtlasPTA
Pathway · p-ccef4f212b · candidate

Nuclear binding-energy difference → Electrical work

Nuclear binding-energy differenceNuclear fissionHot gasMagnetohydrodynamic generationCharge carriersElectrical work

Epistemic state of the route

known constituent relations
4 / 5 established or replicated · weakest constituent demonstrated
constituent maturity floor
K4 · experimentally observed
search for this exact route
Exact composition search: reviewed 2026-09-21 — partial; None found in the runs made (a partial, never a protocol-complete negative): the fission → MHD literature OpenAlex returns is conceptual — gas-core and vapor-core reactor designs feeding disk or vortex MHD channels (1962–1993), closed-cycle nonequilibrium-plasma system studies (2011), numerical fissioning-gas flows (1995) and conductivity models (1992) — with one measured constituent (a neutron-induced helium plasma, 1966) and no report of a fission-heated gas delivering MHD power to a load; the composite-name form adds the whole nuclear-MHD concept literature (1965–2006) and still no such run, and the second reader's own search agrees: Rosa's 10 kW machine ran on an arc furnace and NASA Lewis's closed-loop facility on its own heater, with reactors as the intended future source. One Japanese report (Hattori 1970) remains to be read. Inconclusive as a route search until the Scholar and Semantic Scholar runs exist.
recorded-pathway overlap
shares relations, in order, with Boiling-water reactor direct-steam plant · 2/5 relations shared
route-level evidence
0 sources for the complete composition · 8 cited by the constituent steps
boundaries and interfaces
BOUNDARY compatible · 1 recorded interface
  • mhd-plasma-electrodes · electrode contact · demonstrated · plasma-channel → electrode · carries Charge carriers · within mhd-produces
    the conducting plasma crosses the magnetic field in the generator channel; the induced current is collected at solid electrodes into the external circuit
    the solid electrode is a boundary of the plasma channel, not the active medium of the MHD effect
    Rosa's experimental MHD work (Physics of Fluids 4, 182–194, 1961: an experimental 10 kW generator) used a conducting high-temperature gas and electrodes; the electrode boundary must not make the plasma conversion step inherit state-solid.
    evidence: Physical principles of magnetohydrodynamic power generation

Explorematrix context · physics checks · steps · route evidence · constituent evidence · cite

Matrix context

D = disequilibrium row · C = coupling family column. A cell reads the state of the atlas for that pair.

D.20 × C.27 · Nuclear binding-energy difference × Nuclear heatfamily: Nuclear heatD.20 × C.25 · Nuclear binding-energy difference × Magnetohydrodynamicfamily: Magnetohydrodynamic

Literature search for this exact composition

Reviewed search · 2026-09-21OpenAlexpartial

None found in the runs made (a partial, never a protocol-complete negative): the fission → MHD literature OpenAlex returns is conceptual — gas-core and vapor-core reactor designs feeding disk or vortex MHD channels (1962–1993), closed-cycle nonequilibrium-plasma system studies (2011), numerical fissioning-gas flows (1995) and conductivity models (1992) — with one measured constituent (a neutron-induced helium plasma, 1966) and no report of a fission-heated gas delivering MHD power to a load; the composite-name form adds the whole nuclear-MHD concept literature (1965–2006) and still no such run, and the second reader's own search agrees: Rosa's 10 kW machine ran on an arc furnace and NASA Lewis's closed-loop facility on its own heater, with reactors as the intended future source. One Japanese report (Hattori 1970) remains to be read. Inconclusive as a route search until the Scholar and Semantic Scholar runs exist.

6 runs · 6 attempts blocked before any result (Semantic Scholar, Google Scholar) — attempted, never counted · 247 unique records · 0 read in full · reviewed by Ava Kim's loop-3 lane · protocol route-search-v1
  • Ultra-thin 242mAm fuel elements in nuclear reactors (2000) · insufficient information · Ronen & Shwageraus 2000 (Nucl. Instrum. Methods A): the whole-chain form's only hit — ultra-thin americium-242m fuel elements whose fission fragments escape the fuel, a basis for fission-fragment-heated gas concepts; no abstract on record, the MHD connection unverified.
  • Ultrahigh temperature vapor-core reactor - Magnetohydrodynamic system for space nuclear electric power (1993) · proposal only · Maya, Anghaie, Diaz & Dugan 1993 (J. Propulsion and Power): the conceptual design of a UF₄-fuelled gas-core cavity reactor at 4000 K and 40 atm whose KF-mixed exhaust drives a disk MHD channel below 2300 K, fission-fragment ionization raising the conductivity, 20 % overall efficiency, ~1 kg/kWe at 200 MWe — a design, no device.
  • Flow of a fissioning gas in an outflow disk magnetohydrodynamic generator (1995) · simulation only · Welch, Dugan & Lear 1995 (J. Propulsion and Power): two-dimensional thin-layer Navier–Stokes + MHD + fission-source modelling of a weakly ionized fissioning gas in an outflow disk generator — numerical, no experiment.
  • Electrical Conductivity of UF4-K/KF Gas Partially Ionized by Fission Fragments (1992) · simulation only · Watanabe, Appelbaum & Maya 1992 (Nucl. Sci. Eng.): a chemical-reaction and electron-energy-balance model of the conductivity of a UF₄–K/KF mixture ionized by fission fragments at 2500 K and 1 atm — the constituent step modelled, no measurement, no channel.
  • STUDY OF NUCLEAR SEEDED MHD PLASMAS. (1966) · constituent only · Ellis & Sprague 1966 (DTIC report): analytic and numerical ionization-column models plus measurements of the buildup, equilibrium and decay of a neutron-induced helium (He-3/CO₂) plasma, with an engineering survey of reactor–MHD parameters — the fission → ionized gas step measured, no MHD generator run.
  • Multi-MW Closed Cycle MHD Nuclear Space Power Via Nonequilibrium He/Xe Working Plasma (2011) · proposal only · Litchford & Harada 2011 (NASA report): a systems analysis of a 1800 K fission reactor closed-cycle coupled to an MHD generator with a nonequilibrium He/Xe frozen inert plasma — 55.2 % plant efficiency projected, 2–3 kg/kWe; a study with a three-phase R&D plan, no device.
  • Nuclear Space Power Systems Using Magnetohydrodynamic Vortices (1962) · proposal only · Lewellen & Grabowsky 1962 (ARS Journal): a vortex MHD generator proposed for a nuclear-reactor Rankine space power system, compared with linear channels and turboalternators — a proposal.
  • DIRECT CONVERSION OF NUCLEAR FISSION ENERGY INTO ELECTRICAL ENERGY (1962) · review only · Beckurts & Schretzmann 1962 (OSTI): a survey of direct conversion — thermoelements, thermionic converters and MHD generators in which fission energy heats a gas expanded in a magnetic field — the state of the art in 1962, no experiment of the composition.
  • MHD POWER GENERATION WITH A NUCLEAR REACTOR AS THE HEAT SOURCE. (1970) · insufficient information · Hattori, Noguchi & Tanaka 1970 (OSTI, no abstract): by title a study of reactor-heated MHD generation; whether anything ran is unverified.
  • Open-cycle multi-megawatt MHD space nuclear power facility (2008) · proposal only · Pavshuk & Panchenko 2008 (Atomic Energy): an open-cycle multi-megawatt nuclear-MHD space power facility whose 20 MW MHD-generator parameters are calculated and designed, not measured (the second reader read the abstract) — a design.
  • Gas Core Reactor with Magnetohydrodynamic Power System and Cascading Power Cycle (2004) · proposal only · Nuclear Technology 2004 (with the 2002 conference version): a gas-core reactor coupled to an MHD power system with a cascading cycle, by title — the Florida gas-core programme's design work.
  • Potential of Nuclear MHD Electric Power Systems (1972) · review only · Journal of Spacecraft and Rockets 1972: the potential of nuclear-MHD electric power systems, by title — an assessment.
  • A Review of Basic Studies on MHD Power Generation for Nuclear Applications (1968) · review only · Journal of the Atomic Energy Society of Japan 1968: a review of the basic studies (nonequilibrium ionization, inert-gas generators) for nuclear applications, by title — to be read for any reactor-heated test it may report.
  • Closed-cycle MHD meeting (Report on the international closed-cycle MHD specialists meeting, Jülich, Federal Republic of Germany, 12 - 14 MAY 1970) (1970) · review only · Nuclear Fusion 1970: the Jülich closed-cycle MHD specialists' meeting report, by title — the programmes that aimed at reactor heat sources, none of which is a fission-heated generator run.
  • GASEOUS CORE REACTOR WITH MHD CONVERSION FOR ELECTRICAL POWER GENERATION. (1971) · proposal only · 1971 (OSTI): a gaseous-core reactor with MHD conversion, by title — a concept.
  • Experimental Plans for Subsystems of a Shock Wave Driven Gas Core Reactor · proposal only · Undated report: experimental plans for a shock-wave-driven gas-core reactor's subsystems, by title — plans.
Limitations: OpenAlex only (21/09, 11:17 am Sydney): driver-mechanism 2,909 works reported (the reactor literature), the first 100 by relevance and the first 50 newest screened at title level, the rest unscreened; mechanism-pair 65 (the nuclear-MHD concept literature of 1962–2011 among boundary-layer and nanofluid papers matched on 'MHD effect'); whole-chain 1; demonstration-precision 0; Semantic Scholar answers 429 keyless (owner exception e953) and Google Scholar a captcha — both mandatory for a negative, neither run the composite-name form (21/09, 11:32 am Sydney): four terms frozen on the second reader's ruling (fission-fragment-ionized plasma MHD deliberately excluded as a sibling mechanism); 34 works, screened at title level only — the 1968 Japanese review and the 1970 Jülich report are the places a reactor-heated test would be reported and are unread; Semantic Scholar and Google Scholar owe the form two hits without abstracts (Hattori 1970; Pavshuk & Panchenko 2008) are insufficient-information until read pass 49 (21/09 ~11:29 pm Sydney): every planned Semantic Scholar query was attempted once through the anonymous pool — 5 of 5 answered HTTP 429 at the first request (the runs above, each with its literal query, key and time); Google Scholar served its bot check at the first load of the driver-mechanism form (recorded as an attempt with nothing screened). Both engines are mandatory for a negative under route-search-v1, so the record stays partial and inconclusive: the outstanding obligations are the Semantic Scholar runs for every mandatory key and the Google Scholar runs to the protocol depth; OpenAlex's forms are complete. A blocked request is evidence that an engine was attempted, never that its query returned nothing.
Index query only · 2026-09-21OpenAlex · 6 queriesnot reviewed

5918 indexed works reported across the queries, 247 unique retrieved; nobody has read them for a qualifying demonstration. A person can screen this frozen list and promote it to a reviewed record without re-running the query.

  • OAcomposite-name34 reported · 34 retrieved
  • OAdriver-mechanism:12909 reported · 100 retrieved
  • OAdriver-mechanism:12909 reported · 50 retrieved
  • OAmechanism-pair:1-265 reported · 65 retrieved
  • OAwhole-chain1 reported · 1 retrieved
  • OAdemonstration-precision0 reported · 0 retrieved

Planned runs NOT run in this bundle (engine unavailable): search:2026-09-21-p-ccef4f212b/s2-cn (semantic-scholar); search:2026-09-21-p-ccef4f212b/s2-dm1 (semantic-scholar); search:2026-09-21-p-ccef4f212b/s2-mp12 (semantic-scholar); search:2026-09-21-p-ccef4f212b/s2-wc (semantic-scholar); search:2026-09-21-p-ccef4f212b/s2-dp (semantic-scholar).

Protocol route-search-v1: a frozen index run changes only the search state; only a reviewed record can say that a demonstration was or was not found.

Typed bounds on this route

Every limit the atlas holds for this route, as constraint records: reached through bounded_by claims on the route's own entities. Hard bounds (an upper bound or a formula) decide the thermodynamic-bound check above; benchmarks, constitutive relations and resource limits are listed and never decisive. No prose limit exists anywhere (pass 42).

  • Carnot limit · formula-bound · hard, applies to this route
    η ≤ 1 − T_c/T_h for any heat engine between reservoirs at T_h and T_c

Steps

  1. 01
    Nuclear binding-energy difference —drives→ Nuclear fissionestablishedclaim record
    nuclear → kinetic · loss to radiative
    • for neutron-induced fission: a fissionable nuclide and an incident neutron in an energy range with non-zero fission cross-section
    • critical geometry is required only for a self-sustaining chain reaction; a moderator is reactor-design dependent
    About 200 MeV per event, almost all as fragment kinetic energy (Frisch 1939); thermalisation is a separate step.
    refs [1] [2]
  2. 02
    Nuclear fission —produces→ Hot gasestablishedclaim record
    kinetic → thermal · loss to radiative
    • fission heating produces a vapour or gas working fluid in a DIRECTLY heated, same-circuit configuration: the reactor coolant itself boils in the vessel and its steam goes to the turbine (a boiling-water reactor), or the fissioning or fission-heated gas is the working medium (a gas-core or fissioning-plasma reactor)
    • not a pressurised-water reactor: there fission heats a pressurised liquid whose heat crosses a steam generator into a separate secondary circuit — the heat exchanger, not the core, makes the turbine's steam, and that topology belongs to the system layer, never hidden inside this claim (pass 38)
    refs [3] [4]
  3. 03
    Hot gas —drives→ Magnetohydrodynamic generationdemonstratedclaim record
    thermal → electrical · loss to thermal
    • combustion gas above ~2500 K seeded with potassium to make it conducting
    plasma · above ~700 K · magnetic field required · bulk flow required
    refs [5] [6]
  4. 04
    Magnetohydrodynamic generation —produces→ Charge carriersestablishedclaim record
    electrical → electrical
    refs [5] [7]
  5. 05
    Charge carriers —converts into→ Electrical workestablishedclaim record
    electrical → electrical · loss to thermal
    • carriers driven through an external load at the potential difference the source maintains
    refs [8]

Evidence for the complete composition · 0

No source on record for this exact composition. The sources below support the individual steps, not the route as a whole.

Evidence for the constituent relations · 8

  1. [1]
    O. Hahn, F. Strassmann. Über den Nachweis und das Verhalten der bei der Bestrahlung des Urans mittels Neutronen entstehenden Erdalkalimetalle (1939)
    Naturwissenschaften 27, 11–15 · doi:10.1007/BF01488241 · crossref ✓ 2026-09-19 · record
  2. [2]
    O. R. Frisch. Physical evidence for the division of heavy nuclei under neutron bombardment (1939)
    Nature 143, 276 · doi:10.1038/143276a0 · crossref ✓ 2026-09-19 · record
  3. [3]
    A. Bejan. Advanced Engineering Thermodynamics (4th ed.) (2016)
    Wiley · doi:10.1002/9781119245964 · crossref ✓ 2026-09-19 · record
  4. [4]
    U.S. Nuclear Regulatory Commission. Boiling Water Reactors — how a typical commercial BWR works (2025)
    nrc.gov · www.nrc.gov/reactors/power/bwrs · record
  5. [5]
    R. J. Rosa. Physical principles of magnetohydrodynamic power generation (1961)
    Physics of Fluids 4, 182–194 · doi:10.1063/1.1724426 · crossref ✓ 2026-09-19 · record
  6. [6]
    NASA Lewis Research Center, Electromagnetic Propulsion Division. Lewis Tech Preview: Research Nonequilibrium MHD Power Generator Facility
    NASA Lewis Research Center tech preview N-422 67/11-39 (one page; the date is not printed beyond that document code) · www1.grc.nasa.gov/wp-content/uploads/MHD-Power-Generator-Facility-Tech-Preview.pdf · record
  7. [7]
    L. D. Landau, E. M. Lifshitz, L. P. Pitaevskii. Electrodynamics of Continuous Media (Course of Theoretical Physics, Vol. 8, 2nd ed.) (1984)
    Pergamon · book, no DOI · record
  8. [8]
    N. W. Ashcroft, N. D. Mermin. Solid State Physics (1976)
    Holt, Rinehart and Winston · book, no DOI · record

Cite this route

Physical Transformation Atlas (2026). route p-ccef4f212b: Nuclear binding-energy difference → Nuclear fission → Hot gas → Magnetohydrodynamic generation → Charge carriers → Electrical work. Dataset revision rbfbfcbb70e57 (hash of the canonical data). https://physical-transformation-atlas.wldud5192.workers.dev/path/ccef4f212b

Ids and matrix addresses are stable across revisions; the revision hash identifies the exact canonical files the record was compiled from and is meta.data_hash in every /api export. Reuse terms: see the license field in any export.