COMPONENTS OF A NUCLEAR POWER PLANT

Nuclear Power Plant is also called Nuclear Reactor. Figure shows the schematic diagram of a simple nuclear power plant.

Reactor is the principal part in which heat energy is developed by fission, that is, splitting of uranium atoms.

A cooling medium (water) inside the shield surrounds the reactor. It gets evaporated into steam by absorbing the heat liberated in reactor.

The rest of the system is similar to thermal power plant. Steam expands on the turbine blades and drives the turbine thus heat energy in steam is converted into mechanical energy. This energy drives electrical alternator (generator) which produces power.

Working of a Nuclear Power Plant :

Figure shows a schematic diagram of a nuclear power plant. Its working is as follows,

Uranium fuel is subjected to a nuclear fission which produces lot of heat energy in the reactor.

Water surrounding the reactor absorbs this heat and evaporates into steam. Reactor is shrouded by a biological shield which reduces the radiation intensity.

Steam is passed to the turbine where it expands over rotor blades doing mechanical work. Turbine runs at higher speed and is coupled to an electrical generator (Alternator) which produces electrical power. Exhaust steam which is sufficiently hot is passed to a condenser.

In the condenser cold circulating water absorbs heat from exhaust steam. Condensate is thus formed and leaves the condenser to a hotwell from where it is pumped by feed pump to reactor chamber. Cycle of working is repeated.

Circulating water in condenser which warns up is flown to cooling pond or tower where it is cooled down and recirculated in condenser.

Advantages and Limitations of Nuclear Power Stations :

*Advantages: *

• Highly useful in the event of depletion of fossil fuels.

• Reduce the demand for coal, oil and gas.

• Relatively high energy is generated. (During fission for example, one kg of U-235 would be equivalent to heating value of about 2000 tonnes of coal).

• The plant requires less space.

• Valuable fissile material are obtained as by-products.

• Least atmospheric pollution.

Limitations :

• Danger of radioactivity which may prove harmful to workers.

• Not suitable for variable load operations.

• Very high initial cost.