Nuclear binding-energy difference → Useful heat

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.07 · Nuclear binding-energy difference × Thermophotovoltaicfamily: ThermophotovoltaicD.20 × C.20 · Nuclear binding-energy difference × Photothermalfamily: Photothermal

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, filtered out by its applicability
  η ≤ 1 − T_c/T_h for any heat engine between reservoirs at T_h and T_c
• Visible-band fraction of thermal emission · formula-bound · hard, filtered out by its applicability
  η_vis ≤ ∫₃₈₀ⁿᵐ⁷⁸⁰ⁿᵐ B_λ(λ, T) dλ / σT⁴ — the share of a thermal emitter's radiated power that Planck's distribution places in the visible band at the emitter temperature
• Landsberg limit · formula-bound · hard, filtered out by its applicability
  η ≤ 1 − (4/3)(T_c/T_s) + (1/3)(T_c/T_s)⁴ for conversion of blackbody radiation at T_s with a sink at T_c; 93.3 % at 6000 K / 300 K

Steps

1. 01
   Nuclear binding-energy difference —drives→ Nuclear fusiondemonstratedclaim record

   nuclear → kinetic · loss to radiative

   • for a power-producing D–T thermonuclear plasma: ion temperatures of order 10 keV and a sufficient density–confinement product (Lawson); these are power-balance conditions, not prerequisites for an individual fusion reaction

   plasma · above ~700 K

   Fusion reactions and target-level fusion energy release are experimentally demonstrated (target gain > 1 at NIF, 2022–2024); net electrical output from a fusion power plant is not.

   refs [1] [2] [3]
2. 02
   Nuclear fusion —produces→ Temperature gradientdemonstratedclaim record

   kinetic → thermal · loss to radiative

   • energetic products (neutrons, alphas) deposit their kinetic energy in a blanket or the plasma, which then runs hotter than its surroundings

   refs [2] [3]
3. 03
   Temperature gradient —drives→ Thermal emissionestablishedclaim record

   thermal → radiative

   • an emitter hotter than the surface it faces

   refs [4] [5]
4. 04
   Thermal emission —produces→ Photonsestablishedclaim record

   radiative → radiative

   refs [5] [4]
5. 05
   Photons —drives→ Photothermal absorptionestablishedclaim record

   radiative → thermal

   refs [4]
6. 06
   Photothermal absorption —produces→ Heat flowestablishedclaim record

   thermal → thermal

   refs [4]
7. 07
   Heat flow —converts into→ Useful heatestablishedclaim record

   thermal → thermal

   • heat delivered at a temperature above the point of use

   refs [4]

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 · 5

1. [1]
   H. A. Bethe. Energy production in stars (1939)

   Physical Review 55, 434 · doi:10.1103/PhysRev.55.434 · crossref ✓ 2026-09-19 · record
2. [2]
   J. D. Lawson. Some criteria for a power producing thermonuclear reactor (1957)

   Proceedings of the Physical Society B 70, 6–10 · doi:10.1088/0370-1301/70/1/303 · crossref ✓ 2026-09-19 · record
3. [3]
   H. Abu-Shawareb, et al. (Indirect Drive ICF Collaboration). Achievement of target gain larger than unity in an inertial fusion experiment (2024)

   Physical Review Letters 132, 065102 · doi:10.1103/PhysRevLett.132.065102 · crossref ✓ 2026-09-19 · record
4. [4]
   A. Bejan. Advanced Engineering Thermodynamics (4th ed.) (2016)

   Wiley · doi:10.1002/9781119245964 · crossref ✓ 2026-09-19 · record
5. [5]
   P. T. Landsberg, G. Tonge. Thermodynamic energy conversion efficiencies (1980)

   Journal of Applied Physics 51, R1–R20 · doi:10.1063/1.328187 · crossref ✓ 2026-09-19 · record