POWER PLANT

NUCLEAR REACTOR

Operation

Heavy elements such as Uranium (U235) or Thorium (Th232) are subjected to nuclear fission in a reactor to produce steam at high temperatures and pressure.


Steam runs a steam turbine which converts this energy into mechanical energy.


The turbine drives the alternator which converts mechanical energy into electrical energy.



A nuclear reactor operates by the controlled fission of ²³⁵U. Fission occurs at a slow steady rate, rather than suddenly in a fraction of a second, as in a bomb. Fission produces heat, and this heat is used to generate electricity, in the same way that the heat of burning oil or coal generates electricity in a conventional power plant.


control rods
To keep the reactor running at a constant rate there are cylinders in the pool made of material that readily absorbs neutrons. One example is boron, which has two stable isotopes, ¹⁰₅B and ¹¹₅B. The ¹⁰₅B readily undergoes a neutron absorption reaction, to form ¹¹₅B. If the reactor begins to increase its rate of fission, the control rods are moved a little deeper into the pool. They absorb more neutrons, there are fewer fissions, and the reactor slows down. If the reactor runs too slowly, the control rods are moved a little out of the pool.
Water in the reactor is thus a heat transfer device, a cooling system (to keep the fuel from getting too hot),

Pros & Cons: what this power station presents

Advantages
Small amounts of fuel required
power plant requires Less space
Low running charges
Economical for producing bulk electrical energy
Large available deposits of fuel around the world
Reliability of operation
Does not require large quantities of water for cooling
Disadvantages


Fuel is expensive and hard to recover

Capital cost very high

Erection & commissioning of plant requires great technical knowledge

Fission by-products are generally Radio-active & may cause nuclear pollution

Maintenance costs are high

Not suited for varying loads as reactor does not respond to fluctuations

Disposal of nuclear by-product is difficult & problematic