Mid Term Exam

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Mid Term Exam

• Wednesday March 19 in class
• covers everything weve done so far, up to and
  including fission
• open book

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Typos in Prussins book pages 377,378
eccentricity
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SF t1/2(235U) 1019 years (approximately)
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Oral Presentation Schedule
April 7 Adam Bryant Quark-Gluon Plasma April
14 Erik Swanberg s-Process David
Murer r-Process April 16 Chit Hlaing
Half-life Variations Raluca Scarlat April
23 Barbara Wang NMR April 28 Michelle
Galloway Big Bang Manuel Aldan Cerenkov
radiation April 30 Sven Chilton Tritium
breeding Brien Ninemire K-Isomers May 5
- Amy Coffer
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Krane

• 0.56 MeV for A235
• ? Expect difference in excitation energy between
  235U n and 238U n 2d 1.1 MeV

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Krane
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Krane
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Distributions of number of neutrons emitted from
different fissioning systems
Krane
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Krane
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Nuclear Chain Reaction
2 3 neutrons and
10 g rays emitted per fission
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Krane
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Enge
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238U(n,g)239U neutron capture resonances
Krane
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Whats going on during a single neutron
generation in a reactor
Krane
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Boiling water reactor
Pressurized water reactor
Krane
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CANDU reactor
Gas-cooled reactor
Krane
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Breeder reactor design
Krane
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Natural fission reactor

• 235U 0.00720 0.00001 in natural U today
• However, in 1972, ore from uranium mine in Oklo,
  Gabon showed 235U 0.00717
• Additional Oklo samples showed 235U as low as
  0.00440

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Oklo mine showing uranium ore deposits
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Oklo reactor sites
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235U abundance as function of time
Krane
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Krane
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Krane
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Oklo fission products are still in place in
reactor zone!
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Nuclear weapons
Chain reaction
Multiplication
Note all material on nuclear weapons
obtained from open
online sources
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Critical mass as function of 235U enrichment
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Calutrons used for 235U enrichment at Oak Ridge
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Critical masses for several fissionable nuclides
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Two basic fission weapon designs
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Little Boy Hiroshima 235U gun type bomb
Fat Man Nagasaki 239Pu implosion type bomb
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Gun-type nuclear weapon
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Weapon fizzles if critical mass is not brought
together quickly enough
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First nuclear explosion Trinity
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Hiroshima nuclear explosion
140,000 people killed
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Aftermath of Hiroshima nuclear explosion
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Hiroshima damage map
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Nagasaki explosion
80,000 people killed
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Upshot-Knothole Grable test
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Nuclear explosion at Nevada Test Site
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Nuclear explosion effects test
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US and USSR/Russia nuclear stockpiles