NUCLEAR ENGINEERING by HC120717113911

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```									  NUCLEAR
ENGINEERING
The Fundamentals
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
Symbols, Mass Charge
Symbol   Mass (amu) Charge

Proton          1    1.007276      +1
p
1
1
Neutron
n   0
1.008665      0

Beta        b   0
1
5.485 x10-4   -1


Photon
   0    0             0
0

Neutrino    n        0             0
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

ZNA
A
X   Z
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 %

M 
 i M i 
i
100
   Avogadro’s number is the number of anything in
a mole

24 things
Qu i ckTi m e™ a nd a

N A  0.602310
TIFF (Un co mp res se d) de c omp res so r
a re ne ed ed to se e th is pi c tu re.

mole
   amu- atomic mass unit - the mass of any atom is
numerically equal to the atomic weight of the
atom in question
Mass and Energy
   Mass at rest           Mass of a body in motion
   Etotal=m0c2            Etotal=mc2 where

m0
m
v2
1 2
c
   Kinetic energy

1
            E  m0v 2
2
Particle wavelength
   For Photons use      1.5

1

E  hv           0.5

0                                                         Series2

h is Planck’s constant
1   11   21   31   41   51   61   71   81   91 101

-0.5

and v is frequency     -1

                            -1.5
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.
Stability

Quic kTime™ and a
TIFF ( Uncompressed) decompr essor
ar e need ed to s ee this picture.
Decay schemes

QuickTime™ and a
TIFF (Uncompressed) decompre ssor
are neede d to see this picture.
Half-Life
   The decay rate is
called activity - a
   Units are Ci or
Bq(dis/sec)
   1Ci=3.7x1010 Bq                                  QuickTime™ an d a
TIFF (Uncompressed) decompressor
are need ed to see this p icture .

   Decay constant is l
          ln 2
l
t1/ 2
Image from;www.ehrs.upenn.edu/training/nuc_med/intro.html
Time Rate of Change
   Set up the differential equation
   Change in the number of atoms per time =
production-destruction

dn(t)  ln(t)dt
 lt
n(t)  n 0e
Production in a nuclear
reactor
   Change in the number of atoms per time = production-
destruction

dn
 ln  R
dt
R
n  n 0e   e 
 lt
1  lt

l


Nuclear Reactions
   Conservation of
A  B C  D
q
r
s
t
u
v
w
x          Nucleons
q s u w                  Charge
   Momentum
rt v x                   Energy
Decay Chain
   AB C
   Change in the number of B atoms per time =
production from A -decay from B to C
dnB
  lB n B  lA n A
dt
dnB                            lB t
  l B n B  l A n A 0e
dt
lA n A 0  lA t  lB t
 lB t
n B  n B 0e 
lB  lA
e  e 
Binding Energy
   The energy
necessary to break an
atom apart - Hold the
nuclear together
QuickTime™ and a
TIFF (Uncompressed) decompressor
   Mass defect is the
are need ed to see this picture.
difference in the
measured mass from
the mass you would
get if you summed up
the parts
The calculations
   Mass defect                   Binding Energy
  Z M p  me  NM n  M A
Mev
M p  me   M(H1 )
1                   BE    931
amu
  Z H1  NM n  M A
1

   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
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
1
   Proton    a proton + electron( H1 )
   Alpha       a helium atom ( He 4)
2



Atom Density
   The number of atoms
per unit volume
   General equation
QuickTime™ an d a
TIFF (Uncompressed) decompressor
are need ed to see this p icture .

N A
N
M
Electron density map from
www.geo.arizona.edu/ xtal/geos306/fall04-5.htm
Variations of a Theme
n i N A      n is for molecular
N                density (H2O it is 2 for
M          Hydrogen 1 for
 i N A       Oxygen)
N                is atom %
M         w is weight %
w i N A           Chemical formula
N

XmYn
M             mM x
wx              100
mM x  nM y

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