Nuclear power plant

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)

Fuel Rods:

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.

Reactor:

•         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.

Control Rods:

•         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.

Moderator:

•           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.

Fuel Rods:

•         The fuel rods hold nuclear fuel in a nuclear power plant.

Neutron Reflectors:

•           To prevent the leakage of neutrons to large extent.

•           In PHWR, the moderator itself acts as reflectors.

Shielding:

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