1. PHYSICS OF NUCLEAR WEAPONS

2. Nuclear Binding Energy

3. Nuclear Stability

4. Weapon Types Fission

5. “Little Boy”

6. “Fat Man”

7. Weapon Size

8. Nuclear Weapons & States

9. The Fission Reaction 200 MeV/240 ≈ 0.8 MeV/nucleon ≈ 1,000,000 X E chemical

10. Weapon Types Fusion

11. Two-Stage Thermonuclear

12. The Fusion Reaction 17.6 MeV/5 ≈ 3.5 MeV/nucleon ≈ 5 X E fission

13. Comparison of Fission & Fusion Nuclear FissionNuclear Fusion Definition: Fission is the splitting of a large atom into two or more smaller ones. Fusion is the fusing of two or more lighter atoms into a larger one. Natural occurrence of the process: Fission reaction does not normally occur in nature. Fusion occurs in stars, such as the sun. Byproducts of the reaction: Fission produces many highly radioactive particles. Few radioactive particles are produced by fusion reaction, but if a fission "trigger" is used, radioactive particles will result from that. Conditions: Critical mass of the substance and high- speed neutrons are required. High density, high temperature environment is required. Energy Requirement: Takes little energy to split two atoms in a fission reaction. Extremely high energy is required to bring two or more protons close enough that nuclear forces overcome their electrostatic repulsion. Energy Released: The energy released by fission is a million times greater than that released in chemical reactions; but lower than the energy released by nuclear fusion. The energy released by fusion is three to four times greater than the energy released by fission. Nuclear weapon: One class of nuclear weapon is a fission bomb, also known as an atomic bomb or atom bomb. One class of nuclear weapon is the hydrogen bomb, which uses a fission reaction to "trigger" a fusion reaction.

14. Paths to Fissionable Material

15. Nuclear Fuel - Uranium Ore → Yellow Cake → Enriched

16. Uranium Deposits

18. Uranium Enrichment 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

19. Critical Mass

20. Critical Masses TABLE A-1 Properties of Nuclear-Explosive Nuclides Isotope or Mixture Critical Mass (kg) Half Life (years) Decay Heat (watts/kg) Neutron Production From Spontaneous Fission (per kg-sec) Main Gamma Energies (MeV) U-23316160,0000.281.22.6 from Tl- 208 U-23548700,000,0000.000060.360.19 Np-237592,100,0000.0210.140.087 Pu-23810885602,700,0000.100 Pu-2391024,0002.0220.41 Pu-240376,6007.01,000,0000.10 Pu-24113146.4490.66 from Am- 241 Pu-24289380,0000.121,700,0000.045 Am-241574301101,5000.66

21. 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

22. Enrichment Process

23. Uranium

24. UF 6

25. Enrichment Methods Electromagnetic (Calutron) (≤ 15% enrichment)

26. Enrichment Methods Gaseous Diffusion

27. Enrichment Timeline

28. Enrichment Methods Thermal Diffusion

29. Enrichment Methods Gas Centrifuge

30. Centrifuges Materials: Aluminum → Maraging Steel → Carbon Fiber Composite 100,000 rpm (balanced, magnetic bearings) STUXNET

31. Enrichment Methods LASER Techniques (AVLIS/MLIS)

32. Method Comparison

33. 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