NUCLEAR ENGINEERING

1
NUCLEAR ENGINEERING

• The Fundamentals

2
The Particles

• Electron
• Positron
• Negatron (beta)
• Proton - positive charged
• Neutron-neutral charge
• Unstable when not bound in a nucleus
• Decays to a proton and a b
• Photon - wave/particle duality,
• Neutrino - used to balance energy and momentum on
  nuclear reactions

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Symbols, Mass Charge
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Structure
Nucleus are the protons and neutrons both.
Nucleons are either protons or neutrons
Atomic number is total number of protons Z
Neutron number total number of neutrons N
Atomic mass number sometimes called nucleon
number A
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Your First Equations
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Isotopes

• Atoms with the same number of of protons but
  different numbers of neutrons are Isotopes
• Atomic weight (grams/gmole) - M
• Atomic weight of a mixture of isotopes is when
  isotopic abundance is in

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Avogadros number

• Avogadros number is the number of anything in a
  mole
• amu- atomic mass unit - the mass of any atom is
  numerically equal to the atomic weight of the
  atom in question

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Mass and Energy

• Mass at rest
• Etotalm0c2

• Mass of a body in motion
• Etotalmc2 where
• Kinetic energy

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Particle wavelength

• For Photons use
• h is Plancks constant and v is frequency

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Excited states

• Ground state

• An atom cannot remain in an excited state
  forever. It eventually decays (returns to its
  ground state)when the transition occurs a photon
  is emitted.

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Stability
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Decay schemes
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Half-Life

• The decay rate is called activity - a
• Units are Ci or Bq(dis/sec)
• 1Ci3.7x1010 Bq
• Decay constant is l

Image fromwww.ehrs.upenn.edu/training/nuc_med/int
ro.html
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Time Rate of Change

• Set up the differential equation
• Simple case radioactive decay
• Change in the number of atoms per time
  production-destruction

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Production in a nuclear reactor

• Change in the number of atoms per time
  production-destruction
• When we learn more about neutron R is better
  defined.

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Nuclear Reactions

• Conservation of
• Nucleons
• Charge
• Momentum
• Energy

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Decay Chain

• A?B ?C
• Change in the number of B atoms per time
  production from A -decay from B to C

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Binding Energy

• The energy necessary to break an atom apart -
  Hold the nuclear together
• Mass defect is the difference in the measured
  mass from the mass you would get if you summed up
  the parts

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The calculations

• Mass defect
• Look up MA on a Chart of the nuclides.
• Masses must be isotope specific
• Use Web or come in a use a book in my office

• Binding Energy

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Q value

• Q(initial -final) 931Mev/amu
• exothermic rest mass is converted into kinetic
  energy
• - endothermic kinetic energy converted into rest
  mass
• Use of neutral atoms for binary reactions
• conserve charge
• Proton a proton electron( )
• Alpha a helium atom ( )

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Atom Density

• The number of atoms per unit volume
• General equation

Electron density map from www.geo.arizona.edu/
xtal/geos306/fall04-5.htm
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Variations of a Theme

• n is for molecular density (H2O it is 2 for
  Hydrogen 1 for Oxygen)
• g is atom
• w is weight
• Chemical formula XmYn