Nuclear Power Reactor works on the fission technology it produces the heat and energy and controls it when necessary, this heat is then used to produce steam and this steam is used to run the turbines like in all other conventional electricity generation plants, but nuclear reactor is more environment friendly than the traditional plants, as it does not emits any smoke or gases.
The main parts of reactors
The first part is fuel which is nothing but the tablets of the uranium which are forms as tubes to look like rods; these rods are arranged in the core of reactor.
The second part is moderator, this is used to control the release the energy from the rods, usually water is used as a moderator, but in some plants graphite may also be used.
The third part of Nuclear Power Reactor is control rods which are made up of material which can absorb neutrons, these material are cadmium or boron. These rods are inserted in the core of the reactor to control the rate of radiation in it; they are also used to stop the reactor.
The fourth thing is a coolant, which is a liquid or gas that keeps circulating in the core of the reactor for the purpose of cooling the reactor. It works in the same manner like moderators.
The fifth part is pressure vessel or tubes; these are made up of robust steel in which the core is fitted. It is also consist of series of tubes which hold the fuel and transfer the coolant with moderator.
The other part of Nuclear Power Reactor is a steam generator, it’s also a part of the cooling system, it cools the heat which is coming directly from the reactor, and this part is used to make the steam which is then used to drive the turbine for producing electricity.
The last part is a structure which surrounds the reactor core to protect it from any outside damage, so that the radioactive materials are not slipped away to our environment. This is about a meter thick wall which is made up of concrete and steel.
Most of the Nuclear Power Reactor which are operating in the world are needed to be shutdown before refueling, because when the refueling is done the pressure vessel is needed to be opened. This refueling is done on an interval of one year, in this process one third for the rods are replaced with the new ones. CANDU and RBMK types of reactor have pressure tubes instead of pressure vessel which encloses the reactor core and these reactors can be easily refilled without shutting off the reactor.
It is also possible to run a power reactor on natural uranium in the place of enriched uranium, as natural uranium has the same composition when mined, enriched uranium had the ratio of fissile isotope which is increased by enrichment process, in case of enriched uranium the ordinary water can be used as moderator.
But practically talking the fuel is all ceramic uranium which melts at around 2800 degree Celsius and most of it is enriched, the fuel pellets are arranged in long tubes of zirconium tube to make fuel rods. Zirconium is hard and corrosion resistant and also permeable for the neutrons. The most of these Nuclear Power Reactor are about 4 meters long.
