2. • Nuclear energy is the energy that exists within the nucleus of an
atom.
• Nuclear energy (atomic energy) is released in significant amounts in
processes that affect atomic nuclei, the dense cores of atoms.
• There are two methods of releasing nuclear energy :-
1. Controlled nuclear fission in devices called reactors, which now
operate in many parts of the world for the production
of electricity.
2. Controlled nuclear fusion, holds promise but has not been
perfected.

3. NUCLEAR
ENERGY
NUCLEAR
FISSION
CHAIN REACTION
CONTROLLED
REACTON
UNCONTROLLED
REACTION
NUCLEAR
FUSSION

4. • Nuclear fusion is the combining of two nuclei with low masses to form one
nucleus of larger mass.
• Fusion reactions exist in stars. Our sun is a good example of a
thermonuclear (fusion) reaction.
• It is almost impossible to create fusion reactions on earth since they need
temperatures above one million degrees Celsius in order to take place.
• Nuclear fusion produces less nuclear waste than nuclear fission and the
materials are easier to obtain.

7. CHAIN REACTION
• A chain reaction is an ongoing series of
fission reactions. Billions of reactions
occur each second in a chain reaction.
• Uranium exists as an isotope in the
form of U235 which is unstable.
• When the nucleus of an atom of
Uranium is split, the neutrons released
hit other atoms and split them in turn.
More energy is released each time
another atom splits. This is called a chain

8. On earth, nuclear fission
reactions take place in
nuclear reactors, which
use controlled chain
reactions to generate
electricity.
Uncontrolled chain
reactions takes place
during the explosion of an
atomic bomb.

10. • A nuclear power plant works in a similar way as a thermal power plant .
The difference between the two is in the fuel they use to heat the water in
the boiler.
• Inside a nuclear power station, energy is released by nuclear fission in the
core of the reactor.
• Types of nuclear reactors :-
1. PRESSURIZED WATER REACTOR (PWR)
2. BOILING WATER REACTOR (BWR)
NUCLEAR POWER PLANT

11.  CORE – Here the nuclear fission takes place.
 MODERATOR – This reduces the speed of fast
moving neutrons. Most of them are heavy water
 CONTROL RODS – Control rods limits the
number of fuel atoms that can split. They are
made up boron or cadmium which absorbs
neutrons.
 COOLANT – They carry the intense heat
generated. Water is used as a coolant.
 FUEL – The fuel used for nuclear fission is
U235 Isotope.
 RADIATION SHIELD – To protect he people
working from radiation and radiation
fragments.

14. • Rich energy source.
• A nuclear power plant uses much less fuel than fossil
fuel plant. 1 gram of Uranium-235 delivers as much
energy as 3.5 metric tons of coal.
• Reactors run for years without refueling or being shut
down and need little maintenance.
• No air pollution!
• Space required is less when compared to other power
plants.

15. • Produces Radioactive Waste
• There is no permanent long-term disposal site for
commercial nuclear waste.
• There is a relatively short supply of 235U (only enough left
for 100~200 years)
• Nuclear Power Plants are expensive to build.
• Minor maintenance problems can be very expensive to fix.
• Safety concerns!!!