Los Alamos

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Los Alamos First nuke
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Effects - 500 kT weapon

• Vaporization out to 2 mi.
• Severe blast out to 4 mi. - 65 fatal.
• Ignition out to 5 mi. - 50 fatal.
• 20 kT bomb 3rd degree burns at 3 km20 MT
  bomb 3rd degree burns at 40 km.

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Elements

• Materials are made of atoms.
• Chemical reactions do not change the elements
  nuclei unaffected.
• Nuclear reactions change the nucleus (neutrons
  and protons)

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Chemical Reaction

• Chemical bonds are sharing of electrons between
  atoms.
• A chemical reaction is a change in bonds (or
  adding/removing electrons.)

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Nuclear Reaction

• Change in nuclei (center of atom - much smaller
  than whole atom.)

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Size Energy

• Nucleus of atom is 1/100,000 size of the atom.
• Energies in changes of the nucleus are about
  1,000,000 times greater than in chemical
  reactions.
• Powerful weapons, danger of nuclear wastes
• Efficacy of medical treatment, food irradiation

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What holds nuclei together?

• Protons repel each other.
• So why doesnt the nucleus fly apart?
• Nucleons attract each other strong force.
• This force acts at very short distances when
  nucleons are nearly touching.

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Fusion Fission Reactions

• Fusion small nuclei merge and release energy
  (strong force pulls together, if nuclei get close
  enough.)
• Fission large nucleus falls apart into 2 or more
  pieces.

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Fission

• Spontaneous
• Happens without outside influence
• Given one atom, can wait a long time (billions of
  years.)
• Induced fission
• Can add a neutron, nucleus immediately
  disintegrates.

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Fission Chain Reaction
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Fission Chain Reaction

• Adding a neutron to 235U makes it unstable.
• When it undergoes fission, it releases energy and
  more neutrons.

(neutron)
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Davy Crockett 100 ton equivalent Fatal
radiation at 300 m. Weight about 16 kg
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Fusion bomb(thermonuclear, or H- bomb)
Ulam-Teller design
Plastic
Shield
U-238 jacket