2. Contents
Introduction of NAPS
Layout of NAPS
Working of Nuclear Power Plant
Principal of Nuclear Power Plant
Uranium Fuel Bundle
Calandria
Heavy Water
Moderator System
Shut Down System
Compressed Air System
Cooling Water
CWPH(Circulating Water Pump House)
Feed Water System
3. INTRODUCTION OF NAPS
• Narora atomic power station is situated at the bank of
river Ganga in Bulandshahr district of Uttar Pradesh.
• Naps is involved in generating electricity by utilizing
nuclear energy.
• Naps is laid down on 4th January 1974.
• The heat generated due to fission of Natural Uranium is
removed by circulating D2O Coolant.
• Naps has 2 Natural draft cooling tower and 2 Induced draft
cooling tower.
4. LAYOUT OF NAPS
Administration building
Overhead water tank
Natural draft cooling tower
220KV Switch yard
Stack
Service building
Reactor building
Purification building
Turbine building
Pump House
Station Training centre
Waste Management plant
6. Working of Nuclear Power Plant :-
Nuclear power plants generated electricity from
nuclear heat.
The nuclear heat converts water to steam ,which in
turn drives the turbine and generator to produce
electricity.
Inside a nuclear power station, energy is released by
nuclear fission in the core of nuclear reactor.
1kg of Uranium U-235 produce as much energy as
the burning of 4500 tones of high grade variety of
coal or 2000 tones of oil.
7. Principal of Nuclear Reactor
A Nuclear Power reactor is only a source of heat.
The heat being produced when the uranium atom splits
(fission).
Natural uranium consist of two types (isotopes) of uranium
namely U-235 and U-238 in the ratio of 1:139.
Naturally occurring uranium contains only 0.71% U-235,the
remainder is the non feasible U-238.
When a U-235 atom is struck by a slow (or thermal)
neutron, it splits into two or more fragments.
10. Uranium Fuel Bundle
Uranium fuel bundles are 49.53 cm long & has
8.17cm dia.
Each bundle consists of 19 hermetically seal
zircaloy tubes containing compact & sintered
pallets of natural uranium.
Twelve such bundles are located in each fuel
channel.
12. Calandria
Calandria is the heart of reactor and it is the source
of heat.
Calandria is a cylindrical vessel having 306 Calandria
tubes.
One coolant tube passes through each calandria
tube, and this Coolant tube has 12 fuel Bundles in it
which undergo fission reaction.
13.
14. HEAVY WATER
Heavy water is used as both coolant and
moderator.
Heat energy is transported by coolant from
reactor to the vertical, integral U-tubes in
shell type of heat exchangers.
The absorption of heavy water for neutron is
far less than the ordinary water.
This helps in neutron economy.
15. Moderator System
Moderator system is a
heavy water and helium
system.
Calandria is always full of
moderator up to 96% and
remaining volume is
covered by helium gas.
Working pressure and
temperature of
moderator system are
8Kg/cm 2 and 63℃.
respectively.
16. SHUTDOWN SYSTEM
1. PRIMARY SHUTDOWN SYSTEM
-This system will response in just 2.3 sec.
-This is slow down acting system.
-primary shutdown system has shutoff mechanism at 14
locations in the reactor.
2.SECONDARY SHUTDOWN SYSTEM
-This will used when primary system is fail to shutdown the system.
- This is the fast acting system and respond in 1.4sec.
-secondary shutdown system is a fast acting back up system to the primary
shutdown system.
17. Compressed Air System
The compressed air system has been provided
for the supply of compressed air for the
purpose of-
• Instrumentation(Instrument Air).
• Control service(Service Air).
• Mask air requirement(Mass Air).
18. CWPH(CIRCULATING WATER PUMP HOUSE)
Circulating water system is mainly for removing the latent
heat from the turbine exhaust and maintains the desired
exhaust pressure in condenser.
Some portion of circulating water is supplied -
1. Turbine oil coolers
2. Hydrogen coolers
plant consists of six horizontal opposed balanced type air
compressors, each having nominal capacity of 14.85M3/min.
(Free air delivery = 18.0M3/min) at a pressure 8.5 Kg/cm2 .
19.
20. FEED WATER SYSTEM
Feed water system main function:-
1. Supply adequate high quality water to steam
generator.
2.heat the water from about 49℃ to 170℃.
Feed water pump:-
1.Feed water pump is used to increased the
pressure 350 psi to 1200 psi.
2.Each unit typically will have 2 or 3 Feed
water pumps.
21. Feed Water Pump
Feed pumps usually rotate at about 5000 revolutions per
minute and have an oil lubricating system.