NUCLEAR POWER PLANT
• Nuclear power plant uses nuclear energy from radioactive element for generating electrical energy.
• More than 15% of the world’s electricity i
• It is generally located far away from populated areas.
• In future generation of electricity will be depending on Nuclear Power Plant, as it is economical.
• 1 kg of uranium U -235 can produce electrical power electrical that can be
produced by using 3000 -4500 tonnes of high grade coal or 2000 tonnes of oil.
COMPONENTS OF NUCLEAR POWER PLANT:
Nuclear Fuel :
Normally used nuclear fuel is uranium (U235)
The fuel rods hold nuclear fuel in a nuclear power plant.
Neutron Source: A source of neutron is required to initiate the fission for the first time. A mixture of beryllium with plutonium is commonly used as a source of neutron.
• Nuclear fission takes place in the reactor only.
• Nuclear fission produces large quantity of heat.
• The heat generated in the reactor is carried by coolant circulated through the reactor.
• They are used to control the chain reaction.
• They are absorbers of neutrons.
• The commonly used control rods are made up of cadmium or boron.
• Moderators are used to slow down the fast neutrons.
• It reduces 2 MeV to an average velocity of 0.025 eV.
• Ordinary or heavy water are used as moderators.
• The fuel rods hold nuclear fuel in a nuclear power plant.
• To prevent the leakage of neutrons to large extent.
• In PHWR, the moderator itself acts as reflectors.
To protect from harmful radiations the reactor is surrounded b a concrete wall of thickness about 2 to 2.5 m.
• It is a process of splittin g up of nucleus of fissionable material like uranium into two or more fragments with release of enormous amount of energy.
• The nucleus of U235 is bombarded with high energy neutrons
U235+0n1 Ba 141+Kr92+2.50n1+200 MeV energy.
• The neutrons produced are very fast and can be made to fission other nuclei of U235, thus setting up a chain reactio n.
• Out of 2.5 neutrons relea sed one neutron is used to sustain the chain rea ction.
1 eV = 1.6X10-19 joule.
1 MeV = 106 eV
WORKING PRINCIP LE OF NUCLEAR POWER PLANT:
• The heat generated in the reactor due to the fission of the fuel is taken up by the coolant.
• The hot coolant then lea ves the reactor and flows through the steam gen erator.
• In the steam generator the hot coolant transfers its heat to the feed water which gets converted into steam.
• The steam produced is passed through the turbine, which is coupled wit h generator.
• Hence the power is produced during the running of turbine.
• The exhaust steam from the turbine is condensed in the condenser.
• The condensate then flows to the steam generator through the feed pump.
• The cycle is thus repeated.
Advantages of Nuclear Power Plant:
• Requires less space compared to steam power plant.
• Fuel required is negligible compared to coal requirement.
• Fuel transport cost is less.
• Reliable in operation.
• Cost of erection is less.
• Water required is very less.
Disadvantages of Nuclear Power Plant:
• Initial Cost is higher.
• Not suitable for varying load condition.
• Radioactive wastes are hazardous. Hence these are to be handled with much care.
• Maintenance cost is higher.
• Trained workers are required to operate the plant.
Nuclear Power Plants in India:
• IGCAR, Kalpakkam in Chennai.
• Rana Pratap Sagar in Rajasthan
• Narora in Uttar Pradesh
• Kakarpur near Surat at Gujarat