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PHYSICS OF NUCLEAR WEAPONS. Nuclear Binding Energy. Nuclear Stability. Weapon Types. Fission. “Little Boy”. “Fat Man”. Weapon Size. Nuclear Weapons & States. The Fission Reaction. 200 MeV/240 ≈ 0.8 MeV/nucleon ≈ 1,000,000 X E chemical. Weapon Types. Fusion.
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Weapon Types • Fission
The Fission Reaction 200 MeV/240 ≈ 0.8 MeV/nucleon ≈ 1,000,000 X Echemical
Weapon Types • Fusion
The Fusion Reaction 17.6 MeV/5 ≈ 3.5 MeV/nucleon ≈ 5 X Efission
Nuclear Fuel - Uranium • Ore → Yellow Cake → Enriched
UraniumEnrichment Slightly Enriched (SEU): 0.9%-2.0% Used in Heavy-Water Reactors (HWR) Low-Enriched (LEU): 2%-20% 3%-5% used in Light-Water Reactors (LWR) 12%-19.75% used in Research Reactors Highly Enriched (HEU): >20% ≥ 85% used in weapons primaries ≥ 20% ‘weapons-usable’ in implosion designs 40%-80% used in secondary of two-stage ≥ 20% used in fast neutron reactors 50%-90% used in naval reactors 26.5% in commercial fast reactors
Critical Masses TABLE A-1 Properties of Nuclear-Explosive Nuclides
Comparison of Energy Content • Fission of U-233: 17.8 kt/kg • Fission of U-235: 17.6 kt/kg • Fission of Pu-239: 17.3 kt/kg • Fusion of pure deuterium: 82.2 kt/kg • Fusion of tritium and deuterium (50/50): 80.4 kt/kg • Fusion of lithium-6 deuteride: 64.0 kt/kg • Fusion of lithium-7 deuteride: • Total conversion of matter to energy: 21.47 Mt/kg • Fission of 1.11 g U-235: 1 megawatt-day (thermal) Broader comparison of Energy Densities
Uranium • Isotopic Masses and Abundances • 235U Abundance = 0.720% • 238U Abundance = 99.274% • 235U Mass = 235.04393 (UF6, 349.03433) • 238U Mass = 238.05079 (UF6, 352.04119) • m238/m235 = 1.0086 • = 1.0043 → = 1.0043
Enrichment Methods • Electromagnetic (Calutron) (≤ 15% enrichment)
Enrichment Methods • Gaseous Diffusion
Enrichment Methods • Thermal Diffusion
Enrichment Methods • Gas Centrifuge
Centrifuges • Materials: Aluminum → Maraging Steel → Carbon Fiber Composite • 100,000 rpm (balanced, magnetic bearings) • STUXNET
Enrichment Methods • LASER Techniques (AVLIS/MLIS)
Resources • IAEA/INFCIS • The Atomic Archive • World Nuclear Association • Nuclear Chemistry • Federation of American Scientists • Nuclear Pathways • ALSOS Digital Library • Nuclear Safeguards Education Portal • World Information Service on Energy (WISE) Uranium Project