A nuclear power plant or nuclear power station is a thermal power station in which the heat source is a nuclear reactor. As is typical in all conventional thermal power stations the heat is used to generate steam which drives a steam turbine connected to an electric generator which produces electricity. Enrico Fermi is considered to have invented nuclear power, along with his colleagues at the University of Chicago in 1942, by successfully demonstrating the first controlled self-sustaining nuclear chain reaction.

1. Nuclear Power
Plant

2. Introduction to nuclear power
• Uranium was discovered in 1789 by Martin Klaproth, a
German chemist, and named after the planet Uranus.
• The science of atomic radiation, atomic change and nuclear
fission was developed from 1895 to 1945, much of it in the
last six of those years
• Over 1939-45, most development was focused on the atomic
bomb
• From 1945 attention was given to harnessing this energy in a
controlled fashion for naval propulsion and for making
electricity
• Since 1956 the prime focus has been on the technological
evolution of reliable nuclear power plants.

3. What is nuclear energy?
• Power plants use heat to produce electricity. Nuclear energy produces electricity
from heat through a process called fission. Nuclear power plants use the heat
produced by fission of certain atoms.
1. Nuclear fission
nucleus of atom is split into parts,
produces free neutrons and
energy

4. Nuclear Reactions
• Nuclear reactions deal with interactions between the nuclei
of atoms including of nuclear fission and nuclear fusion
• Both fission and fusion processes deal with matter and
energy
• Fission is the process of splitting of a nucleus into two
"daughter" nuclei leading to energy being released
• Fusion is the process of two "parent" nuclei fuse into one
daughter nucleus leading to energy being released

5. 1.Fission Reaction
• A classic example of a fission
reaction is that of U-235:
• U-235 + 1 Neutron
2 Neutrons + Kr-92 + Ba-142
+ E
• In this example, a stray
neutron strikes an atom of
U235. It absorbs the
neutron and becomes an
unstable atom of U-236. It
then undergoes fission.
These neutrons can strike
other U-235 atoms to initiate
their fission.

6. 2.Fusion Reactions
•A classic example of a fusion reaction is that of
deuterium (heavy hydrogen) and tritium which is
converted to Helium and release energy.
p + p He + n + .42 MeV

7. Nuclear Reactors
A nuclear reactor is a device that permits a controlled fission chain
reaction. In the reactor, neutrons are used to cause a controlled fission of
heavy atoms such as Uranium 235 (U-235). U-235 is a uranium isotope
used to fuel nuclear fission reactors.

8. Reactor is inside a large
containment building

9. CLASSIFICATION OF REACTORS
• The nuclear reactors can be classified as follows :
• 1. Neutron Energy. Depending upon the energy of
the neutrons at the time they are captured by
• the fuel to induce fissions, the reactors can be
named as follows :
• (a) Fast Reactors. In such reactors fission is brought
about by fast (non moderated) neutrons.
• (b) Thermal Reactors or Slow Reactors. In these
reactors the fast moving neutrons are slowed down
by passing them through the moderator.

10. PARTS OF A NUCLEAR
REACTOR
• A nuclear reactor is an apparatus in which heat is
produced due to nuclear fission chain reaction.
• 1. Nuclear Fuel
• 2. Moderator
• 3. Control Rods
• 4. Reflector
• 5. Reactors Vessel
• 6. Biological Shielding
• 7. Coolant.

12. NUCLEAR FUEL
 Nuclear fuel is any material that can be consumed to derive nuclear energy.
The most common type of nuclear fuel is fissile elements that can be made to
undergo nuclear fission chain reactions in a nuclear reactor
 The most common nuclear fuels are 235U and 239Pu. Not all nuclear fuels
are used in fission chain reactions
fuel Thermal
conductivity K-
cal/m. hr°C
Specific
heat
kcal/kg °C
Density kg/m3 Melting point
(°C)
Natural uranium
Uranium oxide
Uranium carbide
16.3
1.8
20.6
0.037
0.078
-
19000
11000
13600
1130
2750
2350

13. CONTROL RODS
Control rods made of a material that absorbs neutrtons are inserted into the
bundle using a mechanism that can rise or lower the control rods.
. The control rods essentially contain neutron absorbers like, boron,
cadmium or indium.
Control rods should possess the following properties :
1. They should have adequate heat transfer properties.
2. They should be stable under heat and radiation.
3. They should be corrosion resistant.
4. They should be sufficient strong and should be able to shut down the
reactor almost instantly
under all conditions.
5. They should have sufficient cross-sectional area for the absorption.

14. MODERATOR
• In the chain reaction the neutrons produced are fast
moving neutrons.
• These fast moving neutronsare far less effective in
causing the fission of U235 and try to escape from the
reactor.
• To improve the utilization of these neutrons their speed
is reduced.
• It is done by colliding them with the nuclei of other
• material which is lighter, does not capture the neutrons
but scatters them.
• Each such collision causes loss of energy, and the speed
of the fast moving neutrons is reduced. Such material is
called Moderator.

15. A moderator should process the following properties :
• 1. It should have high thermal conductivity.
• 2. It should be available in large quantities in pure form.
• 3. It should have high melting point in case of solid
moderators and low melting point in case of liquid
moderators. Solid moderators should also possess good
strength and machinability.
• 4. It should provide good resistance to corrosion.
• 5. It should be stable under heat and radiation.
• 6. It should be able to slow down neutrons.
• Ex-Graphite, heavy water and beryllium are generally used as
moderator.

16. Reflector
• The neutrons produced during the fission process will be
partly absorbed by the fuel rods, moderator, coolant or
structural material etc.
• Neutrons left unabsorbed will try to leave the reactor core
never to return to it and will be lost.Such losses should be
minimized.
• It is done by surrounding the reactor core by a material called
reflector which will send the neutrons back into the core.
• Generally the reflector is made up of graphite and beryllium.

17. REACTOR VESSEL
• It is a strong walled container housing the cure of the power
reactor.
• It contains moderator, reflector, thermal shielding and control
rods.
BIOLOGICAL SHIELDING
• Shielding the radioactive zones in the reactor roan possible
radiation hazard is essential to protect, the operating men
from the harmful effects.
• During fission of nuclear fuel, alpha particles, beta particles,
deadly gamma rays and neutrons are produced.
• A protection must be provided against them. Thick
layers of lead or concrete are provided round the
reactor for stopping the gamma rays.

18. Safety Is Engineered Into Reactor Designs
Containment Vessel
1.5-inch thick steel
Shield Building Wall
3 foot thick reinforced concrete
Dry Well Wall
5 foot thick reinforced concrete
Bio Shield
4 foot thick leaded concrete with
1.5-inch thick steel lining inside and out
Reactor Vessel
4 to 8 inches thick steel
Reactor Fuel
Weir Wall
1.5 foot thick concrete

19. Cladding
• The material that the fuel
rods are made out of is
called cladding.
• It must be permeable to
neutrons and be able to
withstand high heats.
• Typically cladding is
made of stainless steel or
zircaloy.

20. The Pressurized Water Reactor (PWR)
• The Pressurized Water Reactor is a superior nuclear reactor
design and it is the mostly widely used reactor type.
• In this reactor, water in the primary loop, that includes the
reactor vessel and a heat exchanger in the steam generator, is
isolated from water in the steam loop, that includes the steam
generator, the steam turbine, and the condenser.
• The water in the primary loop is pressurized so that it doesn’t
boil and can run at a higher temperature than in a BWR.
• The Pressurized Water Reactor or PWR is safer than the BWR
because all the radioactive material is in the primary loop and
within the containment building.
• The PWR is also more efficient than the BWR because it
converts more of the thermal energy into output energy and
dumps less waste energy to the environment. This is a more
modern reactor than the Boiling Water Reactor.

21. The Pressurized Water Reactor (PWR)

22. Boiling Water Reactor (BWR)

23. • This diagram shows the big picture view of energy
transformations in a boiling water nuclear reactor.
• The thermal energy released in the reactor vessel boils the
water in the vessel and converts the water into steam, the
steam drives the steam turbine, and the steam turbine
drives the electric generator.
• , it is cooled down and condenses as water in the condenser
and goes back again to be heated up in the reactor vessel.
• The radioactive primary loop includes the reactor vessel,
the turbine, and the condenser. The cooling loop that goes
to the cooling tower is not radioactive and the electric
generator is not radioactive. This type of reactor is a
“Boiling Water Reactor” or BWR because it boils water in
the reactor core to make steam.

24. STEAM TURBINE
A steam turbine is a mechanical device that extracts
thermal energy from pressurized steam, and converts it into
useful mechanical
 Various high-performance alloys and superalloys have
been used for steam generator tubing.

25. COOLANT PUMP
The coolant pump pressurizes the coolant to pressures of
the orderof 155bar.
The pressue of the coolant loop is maintained almost
constant with the help of the pump and a pressurizer unit.

26. FEED PUMP
Steam coming out of the turbine, flows through
the condenser for condensation and recirculated
for the next cycle of operation.
The feed pump circulates the condensed water
in the working fluid loop.

27. CONDENSER
Condenser is a device or unit which is used to condense
vapor into liquid.
The objective of the condenser are to reduce the turbine
exhaust pressure to increase the efficiency and to recover
high qyuality feed water in the form of condensate & feed
back it to the steam generator without any further
treatment.

28. COOLING TOWER
Cooling towers are heat removal devices used to transfer
process waste heat to the atmosphere.
Water cirulating throughthe codeser is taken to the
cooling tower for cooling and reuse

29. SITE SELECTION
• 1. Availability of water.
• 2. Distance from load center.
• 3. Distance from populated area.
• 4. Accessibility to site.
• 5. Waste disposal.

30. NUCLEAR POWER STATION IN INDIA
(i) Tarapur Nuclear Power Station:-
• It is India’s first nuclear power plant. It has been built at
Tarapur 60 miles north of Bombay with American
collaboration.
• It has two boiling water reactors each of 200 mW capacity
and uses enriched uranium as its fuel.
(ii) Rana Pratap Sagar (Rajasthan) Nuclear Station.
• It has been built at 42 miles south west of Kota in Rajasthan
with Canadian collaboration. It has two reactors each of 200
mW capacity and uses natural uranium in the form of oxide
as fuel and heavy water as moderator.

31. (iii) Kalpakkam Nuclear Power Station.
• It is the third nuclear power station in India and is
being built at about 40 miles from Madras City.
• It has two fast reactors each of 235 mW capacity
and will use natural uranium as its fuel.
(iv) Narora Nuclear Power Station.
• It is India’s fourth nuclear power station and is
being built at Narora in Bullandshahar District of
Uttar Pradesh. This plant will initially have two units
of 235 mW each and provision has been made to
expand its capacity of 500 mW

32. (v) Kakarpar Nuclear Power Plant.
This fifth nuclear power plant of India is to be
located at Kakarpar near Surat in Gujarat. This
power station will have four reactors each of
235 mW capacity.
(vi) Kaiga Atomic Power Plant.
• The sixth atomic power plant will be located
at Kaiga in Karnataka.
• Kaiga is located away from human
habitation and is a well suited site for an
atomic power plant. It will have two units of
235 mW each

33. ADVANTAGES OF NUCLEAR POWER PLANT
• 1. Space requirement of a nuclear power plant is less.
• 2. A nuclear power plant consumes very small quantity of
fuel.
• 3. There is increased reliability of operation.
• 4. Nuclear power plants are not effected by adverse weather
conditions.
• 5. Nuclear power plants are well suited to meet large power
demands. They give better performance at higher load
factors (80 to 90%).
• 6. Materials expenditure on metal structures, piping, storage
mechanisms are much lower for a nuclear power plant than
a coal burning power plant.

34. DISADVANTAGES
• 1. Initial cost of nuclear power plant is higher as
compared to hydro or steam power plant.
• 2. Nuclear power plants are not well suited for varying
load conditions.
• 3. Radioactive wastes if not disposed carefully may
have bad effect on the health of workers and other
population.
• 4. Maintenance cost of the plant is high.
• 5. It requires trained personnel to handle nuclear
power plants.