Nuclear Chemistry

1
Nuclear Chemistry
2
Facts About the Nucleus

• Very small volume compared to volume of atom
• Essentially entire mass of atom
• Very dense

3
Facts About the Nucleus (continued)

• Composed of protons and neutrons that are tightly
  held together
• Nucleons

4
Facts About the Nucleus (continued)

• The nucleus of a specific isotope is called a
  nuclide
• less than 10 of the known nuclides are
  nonradioactive, most are radioactive
  (radionuclides)

5
Nuclides

• Each nuclide is identified by a symbol where
• X element symbol
• A mass number
• Z atomic number

6
Nuclear Reactions with respect to other changes
Energy drives all reactions, physical, chemical,
biological, and nuclear. Physical reactions
change states of material among solids, liquids,
gases, solutions. Molecules of substances remain
the same. Chemical reactions change the molecules
of substances, but identities of elements remain
the same. Biological reactions are combinations
of chemical and physical reactions. Nuclear
reactions change the atomic nuclei and thus the
identities of nuclides. They are accomplished by
bombardment using subatomic particles or photons.
7
Nuclear Reactions changing the hearts of atoms
Nuclear reactions, usually induced by subatomic
particles a, change the energy states or number
of nucleons of nuclides.
b
After bombarded by a, the nuclide A emits a
subatomic particle b, and changes into B. a A ?
B b or written as A (a,b) B
A (a,b) B
a
B
A
8
Nuclear Reactions

• Radioactive decay a process by which the
  nucleus of a nuclide emits radioactive particles
• Artificial Nuclear Transformation the changing
  of one element into another by bombarding it with
  a nuclide
• Nuclear Fission the process of using a neutron
  to split a heavy nucleus into two smaller nuclei
• Nuclear Fusion the process of combining two
  light nuclei

9
Subatomic Particles for and from Nuclear
Reactions
Subatomic particles used to bombard or emitted in
nuclear reactions
gamma ray (photon) 0? deuterons
electrons alpha particles
protons beta particles
neutrons atomic nuclei
10
Nuclear equations rules

• Sum of reactant mass numbers sum of product
  mass numbers
• Sum of reactant atomic numbers sum of product
  atomic numbers
• emitted particles are on product side
• bombarding or captured particles are on
  reactant side

11
Radiation

• Radiation comes from the nucleus of an atom.
• Unstable nucleus emits a particle or energy
  ? alpha
• ? beta
• ? gamma

12
alpha decay

• an ? particle contains 2 protons and 2 neutrons
• helium nucleus

13
Alpha decay (continued)
14
Beta decay

• a ? particle is like an electron
• moving much faster
• found in the nucleus
• in beta decay a neutron changes into a proton

15
Beta decay (continued)
16
gamma emission

• Gamma (?) rays are high energy photons
• Gamma emission occurs when the nucleus rearranges
• No loss of particles from the nucleus

17
gamma emission (continued)

• No change in the composition of the nucleus
• Same atomic number and mass number
• Generally occurs whenever the nucleus undergoes
  some other type of decay

18
positron emission

• positron has a charge of 1 and negligible mass
• anti-electron
• positrons appear to result from a proton changing
  into a neutron

19
Positron emission (continued)
20
electron capture

• occurs when an inner orbital electron is pulled
  into the nucleus
• no particle emission, but atom changes
• same result as positron emission

21
Electron capture (continued)
22
Artificial Nuclear Transformation

• Nuclear transformation involves changing one
  element into another by bombarding it with small
  nuclei, protons or neutrons
• reaction done in a particle accelerator

23
Artificial Nuclear Transformation (continued)

• man-made transuranium elements

24
Other Nuclear Changes

• a few nuclei are so unstable, that if their
  nucleus is hit just right by a neutron, the large
  nucleus splits into two smaller nuclei - this is
  called fission

25
Fission
26
Other Nuclear Changes (continued)

• small nuclei can be accelerated to such a degree
  that they overcome their charge repulsion and are
  smashed together to make a larger nucleus - this
  is called fusion

27
Fusion
28
Other Nuclear Changes (continued)

• both fission and fusion release enormous amounts
  of energy

29
Learning Check NR1

• Write the nuclear equation for the beta emitter
  Co-60.

30
Solution NR1

• Write the nuclear equation for the
• Beta emitter Co-60.
• 60Co 60Ni 0 e
• 27 28
  -1

31
Learning Check NR2

• What radioactive isotope is produced in the
  following bombardment of boron?
• 10B 4He ? 1n
• 5 2
  0

32
Solution NR2

• What radioactive isotope is produced in the
  following bombardment of boron?
• 10B 4He 13N 1n
• 5 2
  7 0
• nitrogen
• radioisotope

33
Day 2 Radioactivity Effects and Applications
34
Detecting Radioactivity

• To detect something, you need to identify
  something it does
• radioactive rays cause air to become ionized

35
Detection (continued)

• Geiger-Müller Counter works by counting electrons
  generated when Ar gas atoms are ionized by
  radioactive rays

36
Detecting Radioactivity (continued)

• radioactive rays cause certain chemicals to give
  off a flash of light when they strike the
  chemical
• a scintillation counter is able to count the
  number of flashes per minute

37
Scintillation Counters

Photons cause the emission of a short flash in
the Na(Tl)I crystal.The flashes cause the
photo-cathode to emit electrons.
38
Detecting Radioactivity (continued)

• radioactive rays cause chemical changes in some
  materials
• Photographic film is able to record its
  interactions with radioactive particles

39
Photographic Emulsions and Films
Sensitized silver bromide grains of emulsion
develope into blackened grains. Plates and films
are 2-D detectors. Roentegen used photographic
plates to record X-ray image. Photographic plates
helped Beckerel to discover radioactivity. Films
are routinely used to record X-ray images in
medicine but lately digital images are replacing
films. Stacks of films record 3-dimensional
tracks of particles. Photographic plates and
films are routinely used to record images made by
electrons.
40
Half-Life

• Not all radionuclides in a sample decay at once
  (random process)
• The length of time it takes one-half the
  radionuclides to decay is called the half-life

41
Half-life (continued)

• Even though the number of radionuclides changes,
  the length of time it takes for half of them to
  decay does not
• the half-life of a radionuclide is constant

42
Half-life (continued)

• Each radionuclide has its own, unique half-life
• The radionuclide with the shortest half-life will
  have the greater number of decays per minute
  (For samples of equal numbers of radioactive
  atoms)

43
Half-Life of a Radioisotope

• The time for the radiation level to fall (decay)
  to one-half its initial value
• decay curve
• 8 mg 4 mg 2 mg 1 mg

initial
1 half-life
2
3
44
Examples of Half-Life

• Isotope Half life
• C-15 2.4 sec
• Ra-224 3.6 days
• Ra-223 12 days
• I-125 60 days
• C-14 5700 years
• U-235 710 000 000 years

45
Learning Check NR3

• The half life of I-123 is 13 hr. How much of a
  64 mg sample of I-123 is left after 26 hours?

46
Solution NR3

• t1/2 13 hrs
• 26 hours 2 x t1/2
• Amount initial 64mg
• Amount remaining 64 mg x ½ x ½
• 16 mg

47
Ionizing Radiationradioactivity measurements
High energy particles and photons that ionise
atoms and molecules along their tracks in a
medium are called ionizing radiation. For
example, a, b, g, cosmic rays and X-rays are
ionizing radiation. Most radioactive measurement
are based on their ionizing effect. Ionizing
radiation causes illness such as cancer and
death. Radiation effect is a health and safety
concern. Ionizing radiation can also be used in
industry for various purposes. Light and
microwaves that do not ionize atoms and molecules
are called non-ionizing radiation.
48
Interaction of Heavy Charged Particles with Matter
Fast moving protons, 4He, and other nuclei are
heavy charged particles. Coulomb force dominates
charge interaction. They ionize and excite (give
energy to) molecules on their path.
49
Scattering of Electrons in a Medium
Fast moving electrons are light charged
particles. They travel at higher speed., but
scattered easily by electrons.
50
Factors that Determine Biological Effects of
Radiation

• The more energy the radiation has the larger its
  effect can be
• The better the ionizing radiation penetrates
  human tissue, the deeper effect it can have
• Gamma gtgt Beta gt Alpha

51
Factors that Determine Biological Effects of
Radiation (continued)
52
Factors that Determine Biological Effects of
Radiation (continued)

• The more ionizing the radiation (based on mass
  and charge), the greater effect the radiation has
• Alpha gt Beta gt Gamma

53
Radiation Protection

• Shielding
• alpha paper, clothing
• beta lab coat, gloves
• gamma- lead, thick concrete
• Limit time exposed
• Keep distance from source

54
Factors that Determine Biological Effects of
Radiation (continued)
55
Factors that Determine Biological Effects of
Radiation (continued)

• The radioactive half-life of the radionuclide
• The biological half-life of the element
• The physical state of the radioactive material

56
Factors that Determine Biological Effects of
Radiation (continued)

• The amount of danger to humans of radiation is
  measured in the unit rems

57
Somatic Damage

• Somatic Damage is damage which has an impact on
  the organism
• Sickness or Death
• May be seen immediately or in the future
• Depends on the amount of exposure
• Future effects include cancer

58
Genetic Damage

• Genetic Damage occurs when the radiation causes
  damage to reproductive cells or organs resulting
  in damage to future offspring

59
Nuclear Technologies
X-rays give penetrating vision to inner
structures under cover.X-rays and computers give
4-D images of wholes. X-ray diffraction
enables us to determine crystal and molecular
structures, including those of DNA.Ionizing
radiation effects and sterilization empower
industries.Radioactive decay kinetics enables
dating.Radioactivity causes and cures
illness.Nuclear reactions led to nuclide and
element synthesis.Pair productions give
positrons and electrons for accelerators.Positron
-electron annihilations tell stories of organ
functions. Nuclear reactions activate atoms and
nuclides in microscopic samples.Fission and
fusion energy for war and peace.
60
Radiology
Radiology is a scientific discipline dealing with
medical imaging using ionizing radiation,
radionuclides, nuclear magnetic resonance, and
ultrasound. The following procedures are
currently widely available
Central Nervous System Brain,Spine Cardiovascular
System heart, blood vessels Musculoskeletal
System bone, muscles, and joints Digestive,
Urinary, and Respiratory System intestines,
kidneys, liver, stomach, lungs Reproductive
System and Mammography male and female
reproductive organs and breasts
61
X-ray Tubes

• X-ray tubes for industry and sciences.-
  Non-destructive testing X-ray Inspection and
  X-ray Baggage Inspection and Thickness Gauging.
• -There are hundreds of X-ray tubes for medical
  applications.
• Image from prd004-5 of Varian.

62
X-ray Imaging
Absorption of X-ray and gamma-ray by different
material for image today, 2-dimensional solid
state detectors are used in place of films for
X-ray and gamma-ray imaging as shown in this
image by Varian
63
Mammography and CT Scan
X-rays provide the sharpest images of the
breast's inner structure. Mammogram detects small
tumors and changes in the breast tissues.
Computed tomography (CT), scanner takes images by
rotating an x-ray tube around the body while
measuring the constantly changing absorption of
the x-ray beam by different tissues in your body.
The sensitive scanner provides small differences
in absorption of the beam by various tissues. The
information is fed into a computer which
reconstruct images of thin cross sections of the
body.
64
Impact of X-ray Diffraction
Using X-ray diffraction, nearly all structure of
compounds artificially made or isolated from
nature have been determined, including structures
of semiconductors, DNA molecules, and proteins.
Structure data banks serve science, technologies,
and medicine.
65
X-ray Diffraction Results
X-ray diffraction pattern of a single crystal
showing positive image of X-ray beams.
Intensities of these beams allows us to determine
molecular and crystal structures. Various data
banks of structures are now available for
research and development.
66
Medical Uses of Radioisotopes,Diagnosis

• Diagnosis (radiotracers)
• Usually gamma emitters
• Little interaction with tissue
• Therapy
• Alpha or beta emitters (interact with tissue)
• May also emit gamma (detect outside body)

67
Medical Uses of Radioisotopes,Diagnosis

• radiotracers
• certain organs absorb most or all of a particular
  element
• can measure the amount absorbed by using tagged
  isotopes of the element and a Geiger counter

68
Radionuclide in Medicine
Radionuclides are used in imaging for diagnosis
and treatment. Nuclides specifically accumulate
in organs (based on chemical properties) for
image and diagnoses. Radionuclide therapy
selectively deliver radiation doses in target
tissues.
69
History of Nuclear Midicine
1895 discovery of X-rays 1934 discovery of
artificial radioactivity 1937 artificial
radioactivity was used to treat leukemia at UC
Berkeley 1946 use of radioactive iodine cured
thyroid cancer 1948 Abbott Laboratories began
distribution of radioistopes 1950s radioactive
iodine was widely used to diagnose and treat
thyroid 1953 Gordon Brownell and H.H. Sweet
built a positron detector 1971 - The American
Medical Association officially recognized nuclear
medicine as a medical speciality
70
About Nuclear Medicine
There are nearly 100 different nuclear medicine
imaging procedures available today. Nuclear
medicine uniquely provides information about both
the function and structure of virtually every
major organ system within the body. There are
approximately 2,700 full-time equivalent nuclear
medicine physicians and 14,000 certified nuclear
medicine technologists in the U.S.
71
Nuclear Medicine Applications
Neurologic Diagnose stroke, alzheimers disease,
localize seizure foci, evaluate post
concussion Oncologic Tumor localization,
staging, and response to treatments Orthopedic
Evaluate bone, arthritic changes, and extent of
tumors Renal Detect urinary tract obstruction
and measure renal functions Cardiac Diagnose
coronary artery, measure effectiveness of bypass
surgery, identify patients of high risk heart
attack, and diagnose heart attacks Pulmonary
Measure lung functions Other Diagnose and Treat
Hyperthyroidism (Grave's Disease)
72
Irradiation Sterilization
Irradiation by ionizing radiation kills bacteria
and cells. This effect has been applied for the
following areas sterilize medical
equipment sterilize consumer products such as
baby bottle, pacifiers, hygiene products, hair
brush, sewage sterilize common home and industry
products food preservation
73
Irradiation for Food Processing
Soon after discovery, X-rays were used to kill
insects and their eggs. After WWII, spent fuel
rod were used to sterilize food, but soon, 60Co
was found easier to use in th 1950s. The US army
played a key role in R D of food processing,
and soon other countries followed. In 1958, USSR
granted irradiation of potatoes for sprout
inhibition. Canada granted irradiation of
potatoes, onions, wheat, dry spices. However,
food processing has many other problems such as
regulation, labelling, marketing and public
acceptance to deal with.
74
Object dating

• archeological (once living materials)
• compare the amount of C-14 to C-12
• C-14 radioactive with half-life 5730yrs.
• while living, C-14/C-12 fairly constant

75
Object dating (continued)

• CO2 in air ultimate source of all C in body
• atmospheric chemistry keeps producing C-14 at the
  same rate it decays
• Upon death, C-14/C-12 ratio decreases
• limit up to 50,000 years

76
Radiocarbon Formation and Exchange
Cosmic rays
14N
n
proton
14C
14CO2
CO2
77
Physical Data of 14C
Beta energy 156keV (maximum), 49 keV (ave) Half
life 5730 y Biological half life 12 dEffective
half life 12 d (unbound) 40 d (bound) Max. beta
range in air 24 cmMax. beta range in water 0.28
mm Best used to date objects less than 50,000
years old.
78
Object Dating

• mineral (geological)
• compare the amount of U-238 to Pb-206
• compare amount of K-40 to Ar-40

79
Radiopotassium 40K Dating
Radiopotassium 40K decays to stable 40Ar. Thus,
by measuring relative ratio of 40K and 40Ar in
rocks enable us to determine the age of rocks
since its formation.The half life of 40K is
1.25e9 y.
80
Fissionable Material

• fissionable isotopes include U-235, Pu-239, and
  Pu-240
• natural uranium is less than 1 U-235
• rest mostly U-238
• not enough U-235 to sustain chain reaction

81
Fissionable Material (continued)

• fission produces about 2.1 x 1013 J/mol of U-235
• 26 million times the energy of burning 1 mole CH4
  
• to produce fissionable uranium the natural
  uranium must be enriched in U-235

82
Fission Chain Reaction

• a chain reaction occurs when a reactant is also a
  product
• in the fission process it is the neutrons
• only need a small amount of neutrons to keep the
  chain going

83
Fission Chain Reaction (continued)

• many of the neutrons produced in the fission are
  either ejected from the uranium before they hit
  another U-235 or are absorbed by the surrounding
  U-238

84
Fission Chain Reaction (continued)

• minimum amount of fissionable isotope needed to
  sustain the chain reaction is called the critical
  mass

85
Nuclear fission
86
Nuclear fission
87
Energy Nuclear Science
The most important aspect of nuclear technology
is the large amount of energy involved in nuclear
changes, radioactivity, nuclear reactions,
radiation effects etc. Nuclear energy associates
with mass according to Einsteins formula, E
m c 2but what does it mean?
E m c2
88
Where does the energy come from?

• At the nuclear level, mass and energy are
  interchangeable.
• Mass is converted to energy
• Energy is converted to mass

89
Where does the energy come from?

• The mass of a nuclide is less than the sum of the
  masses of its constituent parts (protons and
  neutrons

90
Where does the energy come from?

• Proton 1.00728 amu
• Neutron 1.00866 amu
• Expected mass of
• 2 x 1.00728 2 x 1.00866
• 4.03188 amu

91
Where does the energy come from?

• Actual mass of
• 4.0026 amu
• Difference 0.02928 amu
• Where did this mass go?

92
Where does the energy come from?

• The difference in the expected mass and the
  actual mass is called the mass defect.
• This mass is converted into the energy used to
  hold the nucleus together.

93
Where does the energy come from?

• Protons are positively charged. If there were no
  force holding them together, the protons in the
  nucleus would repel each other.
• This force is called the nuclear strong force.
• The energy used for this force is called binding
  energy.

94
Where does the energy come from?

• E mc2
• Binding energy (mass defect) x c2
• Note mass defect must be in kg
• (1 amu 1.66054x10-27 kg)

95
Where does the energy come from?

• Binding energy for
• 0.02928amu(1.66054 x 10-27 kg/amu)
• 4.86206 x 10-29 kg
• E 4.86206 x 10-29 kg x (2.998x108 m/s)2
• 4.3700x10-12 J

96
Estimate Energy in Nuclear Reactions
Similarly, the energy in a nuclear reaction is
determined based on the mass difference between
the mass of the reactants and the mass of the
products. Energy (mass of products mass of
reactants) x c2 For exothermic reactions (e.g.,
fission or fusion) the mass of the products is
less than the mass of the reactants. In these
reactions, the mass is converted to energy.
97
Nuclear Power Plants

• use fission of U-235 or Pu-240 to make heat
• the fission reaction takes place in the reactor
  core

98
Nuclear Power Plants
99
Nuclear Power Plants (continued)

• heat picked up by coolant and transferred to the
  boiler
• in the boiler the heat boils water, changes it to
  steam, which turns a turbine, which generates
  electricity

100
Nuclear Power Plants - Core

• the fissionable material is stored in long tubes
  arranged in a matrix called fuel rods
• subcritical

101
Nuclear Power Plants - Core (continued)

• between the fuel rods are control rods made of
  neutron absorbing material
• B and/or Cd
• neutrons needed to sustain the chain reaction

102
Nuclear Power Plants - Core (continued)

• the rods are placed in a material used to slow
  down the ejected neutrons called a moderator
• allows chain reaction to occur below critical mass

103
Reactor core (fuel) enriched or natural
U, 239PuModerators graphite, H2O,
D2O He (100 Atm and 1273 K) Be (high
temperature liquid metal). Na (773 to 873 K
for breeder reactor) BeF2 ZrF4 ( for
GCR)Control rods Cadmium, Boron, Carbon,
Cobalt, Silver, Hafnium, and Gadolinium, ?
c 255 kb for 157Gd Monitoring devices
Neutron and radioactivity detectors, T, etc
Energy transfer system Moderator or liquid
Key Components of Nuclear Reactors
104
Reactor accidents
An accident is a series of undesirable events
that took place due to accumulated
causes. Nuclear accidents attract more attention
due to release of radioactive nuclides. Radioactiv
ity causes fear, because most people know little
about it. Many nuclear accidents have happened.
105
TMI-2 Reactor accidents
March 28, 1979, two pumps failed to supply feed
water steam generator. Valve of auxiliary pump
was closed by error and auxiliary pump failed to
operate. Pressure increased and relieve valves
opened. Relieve valves failed to close resulting
in a loss of coolant. Zircaloy-4 oxidized by
water, producing a large volume of hydrogen
gas. Core overheated resulting in meltdown
106
The TMI-2 Reactor Design
107
The TMI-2 Core After the Accident
Four years later, photo image of TMI2 core
shows damage to its uranium fuel rods more
extensive than originally thought just after he
accident. Core meltdown shows the temperature
reached 5000 K.
http//washingtonpost.com/wp-srv/national/longterm
/tmi/gallery/photo10.htm
108
Fission Products in the Core After the Accident
Long-life Fission Products in the Core after
TMI-2 Accident Isotope Activity /Ci
Half-life Amount 85K 9.7?104 10.7
y 4.7?1013 90Sr 7.5?105 28.8
y 9.8?1014 129I 2.2?103 1.6?107
y 1.6?1012 131I 7.0?107 8.04
d 7.0?1013 133Xe 1.5?108 5.25
d 9.8?1013 137Cs 8.4?105 30.2
y 1.1?1015 Amount Activity ? half-life
(s)/0.693
109
The Chernobyl Accident
RBMK graphite-moderated, channel-tube-cooled
reactors. Reactor 4 in Chernobyl had been in
operation for 3 years prior to the
accident. April 26, 1986, Reactor 4 at Chernobyl
was scheduled for a safety test to see if
residual power is sufficient to operate the
reactor safely in case of a sudden power
failure. Operators turned off cooling system and
powered down. When power from the reactor failed
to operate the reactor safely, they used power
from the grid without notifying grid controller.
Radioactivity of fission products overheat the
core. When they turned up power with cooling
system off, the core fragmented and exploded
destroying the building. Radioactivity (fallout)
spread to north Europe.
110
The Soviet RBMK Reactor Design
The Soviet RBMK reactor has individual fuel
channels, using ordinary water as coolant and
graphite as moderator. It evolved from reactors
designed for 239Pu production.
111
Power Nuclear Reactors in the World
nucleartourist.com/world/wwide1.htm
112
Major work sitesOak Ridge 59,000-acre Hanford
Engineer Work 450,000-acreProject Y (Los Alamos
Laboratory) Chicago, Berkley, Montreal, New York
The First Fission Bomb Explosion
July 16, 1945, a plutonium (Fat Man) bomb was
tested in Journey of Death. Two hemispheres of
239Pu were forced together to reach criticality.
The bomb was attached to a 30-meter steel tower,
which disappeared after the explosion.
113
Fission Energy For War
At 815 am August 6, 1945, Little Boy (235U) was
dropped on Hiroshima by a modified B-29 bomber.
On the 9th, a 239Pu-fuelled bomb exploded over
Nagasaki
Destruction by atomic bomb Light and energy
(heat) Shock wave Secondary fire
Radioactive fission products in the fallout
114
Reducing Critical Masses by Implosion
115
Producing Bomb Materials
Separate 235U (0.7) from natural uranium gas
diffusion of UF6 centrifuge of UF6 gas thermal
diffusion of UF6 gas electromagnetic
separation Production of 239Pu by the
reaction 238U(n, 2b)239Pu
116
Bomb Material Separating 235U by gas Diffusion
? One diffusion unit and the diffusion plant ?
The blue spot is a personhttp//www.npp.hu/uran/3
diff-e.htm
117
Bomb Material Separating 235U by Electromagnetic
method
Bomb Material Separating 235U by Electromagnetic
meth
The principle of this method is the same as the
mass spectrometry for chemical analysis. This is
still a very important method for chemical
analysis today.
118
(No Transcript)
119
Isotope Separation by Plasma Centrifuge
A vacuum arc produces a plasma column which
rotates by action of an applied magnetic field.
The heavier isotopes concentrate in the outer
edge of the plasma column resulting in an
enriched mixture that can be selectively extracted
120
Nuclear Fusion

• Fusion is the process of combining two light
  nuclei to form a heavier nucleus
• The suns energy comes from fusion of hydrogen to
  produce helium

121
Nuclear Fusion (continued)

• Releases more energy per gram than fission
• Requires high temperatures and large amounts of
  energy to initiate, but should continue if you
  can get it started

122
Nuclear Fusion

• Fusion
• small nuclei combine
• 2H 3H 4He 1n
• 1 1
  2 0
• Occurs in the sun and other stars

Energy
123
Nuclear Fusion in Stars
Stars are giant fusion reactors. Nuclear fusion
reactions provide energy in the Sun and other
stars. Solar energy drives the weather and makes
plants grow. Energy stored in plants sustains
animal lives, ours included.
124
The Sun Core Radius 0.25 Rsun T 15 Million
K Density 150 g/cc Envelope Radius Rsun
700,000 km T 5800 K Density 10-7 g/cc Life
of Startug-of-war between Gravity Pressure

125
The solar surface
126
Nuclear Fusion and Plasma
D and T mixtures have to be heated to 10 million
degrees. At these temperatures, the mixture is a
plasma. A plasma is a macroscopically neutral
collection of charged particles. Ions (bare
nuclei) at high temperature have high kinetic
energy and they approach each other within 1 fm,
a distance strong force being effective to cause
fusion.
127
Nuclear Fusion and Plasma Confinements
Three confinement methods
fd3.gif from ippex.pppl.gov/ippex/module_5/see_fs
n.html
128
Nuclear Fusion using Tokamak
The Tokamak technology for plasma confinement in
fusion
fd4.gifltippex.pppl.gov/ippex/module_5/see_fsn.htm
l
129
Fusion Research in U.S.A.

• Princeton Plasma Physics Laboratory (PPPL).
• Oak Ridge National Laboratory (ORNL).
• Massachusetts Institute of Technology, Alcator
  C-Mod.
• University of Wisconsin, HSX.
• University of Texas, Fusion Research Center.
• Max Planck Institut fur Plasmaphysik, Wendelstein
  7-AS
•  

130
Nuclear Fusion Energised the Cold War
During WW2, the USSR competed with UK and US for
military superiority. The Cold War started. Sept.
23, 1949, President Truman told the world about
the Soviet explosion of A-bomb. The US stepped up
to develop the H-bomb. 1952, Nov. 1. US tested
the first H-bomb at Enewetak 1953 the USSR tested
an H-bomb Britain, France, and China also have
tested H-bombs. The cold war was red hot until
the former USSR disintegrated.
131
H-bomb
Nov. 1, 1952, the first H-bomb Mike
tested,mushroom cloud was 8 miles across and 27
miles highthe canopy was 100 miles wide, 80
million tons of earth was vaporized. H-bomb
exploded Mar. 1, 1954 at Bikini Atoll yielded 15
megatons and had a fireball 4 miles in
diameter.USSR H-bomb yields 100 megatons.