3. Plan of Presentation
Nuclear fission – Atom Bomb
Nuclear fusion – Hydrogen bomb
Applications of radioactive isotopes
4. Atomic Structure
Atoms are composed of protons, neutrons and electrons
Protons – positively charged particles
Neutrons – neutral particles
Electrons – negatively charged particles
Protons and neutrons are located in the nucleus
Electrons are found in orbitals surrounding the nucleus
The central part of an atom
Composed of protons and neutrons
A strong attractive force between nucleons in the
atomic nucleus that holds the nucleus together
Heavy nucleus splits into lighter nuclei and energy is released
Nucleus can be induced to undergo fission by bombardment with
It is much easier to crash a neutral neutron than a positive proton
into a nucleus to release energy
12. Germany started experimenting
with Nuclear Fission in 1938.
German scientist Otto Hahn and
Fritz Strassman bombarded
Uranium with neutrons and
discovered Barium atoms.
Conclusion: Nuclear fission
releases a massive amount of
13. Dropped on Hiroshima, on August 6, 1945
The "Little Boy" - 3 m in length, 71 cm
wide and weighed 4000 kg
-7 feet 8 inches (2.34 m) long, five feet
(1.52 m) in diameter, and weighed
10,200 pounds (4,630 kg) - detonated
over Nagasaki at an altitude of about
1,800 feet - Uses plutonium
Little Boy Fat Man
17. Chain Reaction
• A chain reaction is an
ongoing series of fission
reactions. Billions of
reactions occur each
second in a chain
18. Nuclear Fusion
• The opposite of fission, fusion is when 2 nuclei combine to
form a larger nucleus.
• A large amount of energy is generated during nuclear fusion.
• Small nuclei combine to form heavier, more stable nuclei.
• No radioactive products are produced.
• Fusion reactions are easier to control, so the risk of
explosions & accidents are decreased.
19. Nuclear Fusion
When two light
atoms join to form
Energy is also
Sun, stars and
21. THERMONUCLEAR (HYDROGEN) BOMB
A fission bomb is exploded around the fusion fuel to
produce the high temperatures and density required
for a fusion chain reaction in a thermonuclear bomb.
22. Nuclear Fusion
• Atoms lighter than Fe. Deuterium used
• Requires extremely high temperatures ~ 1 billion K
• Currently not technically possible for use as a power source – issues with
• Used as “Hydrogen bomb”
• Sun’s energy captured for our use
Nuclear power generation does emit relatively low amounts of
carbon dioxide (CO2). The emissions of green house gases and
therefore the contribution of nuclear power plants to global
warming is therefore relatively little.
This technology is readily available, it does not have to be
It is possible to generate a high amount of electrical energy in one
Nuclear power plants as well as nuclear waste could be preferred
targets for terrorist attacks..
During the operation of nuclear power plants, radioactive waste is
produced, which in turn can be used for the production of nuclear
26. Operating Nuclear Power Plants in India
TARAPUR-1&2 RAJASTHAN-1to 6 MADRAS-1&2
NARORA-1&2 KAKRAPARA-1&2 KAIGA-1 to 4
Total Capacity 4780 MWe
36. Nuclear Reactions
• Two types:
–Fission = the splitting of nuclei
–Fusion = the joining of nuclei (they fuse
• Both reactions involve extremely large
amounts of energy
equation E = mc2
illustrates the energy
found in even small
amounts of matter
37. Presentation of Lecture Outlines, 21–37
• Nuclear fission is a nuclear reaction in which a
heavy nucleus splits into lighter nuclei and
energy is released.
– In some cases a nucleus can be induced to undergo fission by
bombardment with neutrons.
39. Fissionable Isotopes
• U-235 is fissionable, but U-238 is not.
• Pu-239 is fissionable
• Th-232 is fissionable only with a fast moving
• Slow-moving neutrons are used for controlled
fission reactions in power plants.
40. Nuclear Fission
When a heavy atomic
nucleus is bombarded
with a neutron…
Two middle weight
Neutrons and Energy
= Chain Reaction!
stations and bombs