1. Reactors and Bombs Short Version

2. Reactor Components Moderator – Small A – Small probability of absorbing neutrons; Water Heavy water (deuterium) Graphite Coolant Control Rods – Absorbers that suck up neutrons Cadmium, indium, boron Delayed neutrons (0.7%)

4. Uranium Isotopes

5. Enrichment Numbers Low-Enriched Uranium (LEU) or Reactor Grade Fuel = 3-5% U 235 Highly-Enriched Uranium (HEU) or Weapons Grade Fuel = 80- 95% U 235

6. Enrichment - Centrifuge

7. Centrifuge Cascade

9. Uranium Is Encased in Solid Ceramic Pellets

10. Fuel Pellet

11. Nuclear Fuel Assembly Fuel Pellet

12. Reactor Core

13. Boiling Water Reactor

15. PWR

17. CANDU

18. Graphite Reactor

19. Plutonium Production

20. www.ieer.org/sdafiles/ vol_5/5-1/purexch.

21. Breeder Reactor

22. TMI

24. Chernobyl Reactor

26. Contamination

31. History Part 2 1939 – Neils Bohr and John Wheeler proposed detailed theory (Liquid Drop Model) 1939 – Fermi unsuccessfully tried to alert US Navy of importance of research 1939 – Einstein’s famous letter to Roosevelt (Szilard, and Wigner) 1941 – Britain joins US effort 1942 – Fermi, first reactor in Chicago, Oppenheimer in charge.

32. Neutrons From Fission Possible Fission Fuel IsotopeAverage Neutron Released SlowFast 233 U2.292.45 235 U2.072.30 238 U00.97 U - natural1.341.02 239 Pu2.082.45

33. Manhattan Project Gen GrovesOppenheimer

34. Oak Ridge - K-25 Enrichment Plant - 235 U

35. Hanford Reactor – 239 Pu

36. Los Alamos – Science, Assembly

39. Critical “Mass” How much material needed to sustain a chain reaction and build a weapon. Depends on – Mass – Shape – Density – Configuration

40. Critical Masses FuelCritical Mass W/O With Tamper (U) With Tamper (Be) Natural Uranium No! 20 % 235 U160 kg65 kg 50 % 235 U68 kg25 kg 100 % 235 U47 kg16 kg14 kg 80 % 239 Pu5.4 kg 100 % 239 Pu10 kg4.5 kg4 kg

41. Explosion Sequence Numbers of Fissions Boom!

42. Yield Yield of Nuclear Weapons in equivalent explosive power of tonnes of TNT – (1 tonne = 1000 kg) 1 kT = 1000 tonnes is equivalent to 4.2x10 12 J of energy – (from 0.056 kg of 235 U) 1 MT = 1 million tonnes of TNT

43. Gun-Barrel Device

44. Little Boy: A Gun-Type Bomb 28” in diameter, 10” long, 9,000 lbs 50 kg of Uranium, 70% 235 U Critical mass = 17” in diameter Y = 12.5 kT

45. Neutron Trigger PoBe Thin metal foil

46. Plutonium Bomb In a Reactor three isotopes of Plutonium produced 239 Pu, 240 Pu, 241 Pu 240 Pu and 241 Pu undergo spontaneous fission A gun barrel design too slow to prevent a “fizzle” Spontaneous Fission 240 Pu and 241 Pu

47. Plutonium Bomb In a Reactor three isotopes of Plutonium produced 239 Pu, 240 Pu, 241 Pu 240 Pu and 241 Pu undergo spontaneous fission A gun barrel design too slow to prevent a “fizzle”

48. Fat Man: Implosion-type bomb

50. Fat Man: Implosion-Type Bomb 60” in diameter, 10”8” long 5 kg of Pu Y = 20 kT

51. Nuclear Fusion

52. 1 st Use of Fusion

53. Fusion Boosted Fission Weapon

54. Normal sequence, of fission generations. Boom! Boosted Weapon Bigger Boom!

55. Second Use of Fusion Actual Fusion Explosion Used Liquid tritium and deuterium Size of a building 10 MT 1952

56. Important Elements of Fusion Bomb Lithium Hydride (LH) but made with deuterium Lithium deuteride LD Just need a source of neutrons and lots of energy and high temperatures

57. Fission Bomb!

58. Sequence of Events 1.High explosive detonates – compresses Pu and trigger 2.Fission occurs 3.Neutrons reflected by casing changes lithium to tritium 4.X-rays focused by Styrofoam unto LD target 5.Fusion occurs releasing energy AND NEUTRONS 6.If outer casing made of 238 U, a second large fission explosion occurs! (If made of 235 U, an even bigger fission explosion (x2)) Possible Fission Fuel IsotopeAverage Neutron Released SlowFast 233 U2.292.45 235 U2.072.30 238 U00.97 U - natural1.341.02 239 Pu2.082.45

59. Fusion Weapon