Main Components of Nuclear Power Plant
The chief components of Nuclear Power Plant are –
Nuclear fuel
Nuclear Fuel is fissionable chemical element or nuclei. They should undergo nuclear fission past times nuclear bombardment. They should live able to sustain the nuclear chain reaction. Examples of Nuclear fuels are U233 , U235 , Pu239 .
The per centum of dissimilar Uranium isotopes inward the Earth’s crust is
U238 = 99.3% ; U235 = 0.7% together with U234 = solely describe
Here U235 is most unstable together with tin sustain chain reaction. And thence it has the advert Primary Fuel for Nuclear Power Plant. U233 and Pu239 are produced from Th232 and U238 respectively. And these are called secondary fuels.
Moderator
In Nuclear reactor because of the chain reactor fast moving neutrons are produced from U235 which are non adept for chain reaction to popular off ahead. So to command the speed of these neutrons past times using the nuclei of simply about other element. Fast moving neutrons collide amongst that cloth together with their speed is reduced. And thence deadening neutrons (Thermal Neutrons) are got which are adept for reaction. This obstruction for the fast neutrons is called moderator. Graphite, Deuterium Oxide (Heavy water) together with Beryllium are mostly used equally moderator materials.
Control Rods
In the Nuclear Reactor the consumption of fuel together with reactor ability flat depends on the neutron flux on the core. The unloose energy produced inward the reactor is mostly really high together with if the reaction charge per unit of measurement is non controlled properly than in that location is a possibility of impairment of the whole structure. And radioactive products tin brand the institute site contaminated. So to command the ability of reactor command rods are used. These command rods tin live cylindrical or inward the canvass form. These rods are inserted or moved out of the reactor. Their insertion increases the absorption of the neutrons together with withdrawal causes less electrons to live absorbed. So insertion damps the reaction. Generally controls Rods are made of Boron or Cadmium.
Reflector
In the Nuclear Reactor the neutrons unabsorbed endeavour to escape the reactor. Once they motion out of the marrow they are lost. So to these losses should live diminished. So the unabsorbed neutrons are reflected dorsum to the marrow past times using a cloth inward the marrow surrounding. These are called reflector. Generally Beryllium together with Graphite are used for making reflectors.
Reactor Vessel
Reactor vessel is made of potent materials. It contains all the reactor elements similar fuel rods, moderators, command rods, shields etc.
Biological Shielding
This shielding is done to protect men from harmful radiations. From the nuclear reactors harmful alpha particles, beta particles together with really unsafe gamma rays are emitted. Thick layers of concretes are used to protect from gamma rays. Thick metallic or plastic shielding is plenty for alpha together with beta to live stopped.
Coolant
Coolant used inward Nuclear reactors for transferring large amount estrus produced because of nuclear chain reaction. Coolants should possess got high boiling indicate together with depression melting point. It should possess got high estrus transfer co efficient. Different types of fluids are used equally coolants such equally low-cal water, heavy water, Helium, Hydrogen, Carbon Dioxide, Liquid Sodium together with Potassium etc.
Different Types of Nuclear Reactors amongst schematic diagram
Boiling Water Reactor (BWR)
In this type of reactor enriched Uranium is used. In enriched uranium U235 is increased inward percentage. Water is used equally a coolant. It takes estrus together with becomes steam together with goes to the Steam Turbine. Here H2O is used equally a moderator also.
Pressurized Water Reactor (PWR)
Here Water is used equally coolant together with equally good moderator. Uranium is role equally the fuel. Here a pressurizer is used to increment the H2O clitoris per unit of measurement area to nigh 1200 psig. It is done to popular off along the H2O inward the liquid soil because inward atmospheric status H2O volition boil at 100 marking Celsius. Pressure enables H2O to rest inward liquid soil together with equally a upshot it takes to a greater extent than heat. This heated H2O goes to steam generator where feed H2O is turned to steam.
Sodium Graphite Reactor (SGR)
Here, Na is used equally the primary coolant. Sodium Potassium is used equally secondary coolant. As Sodium has a high boiling indicate it provides high outlet temperatures. This estrus tin live utilized to arrive at high temperature steam. As a upshot the efficiency volition equally good live increased. By using sodium equally a primary coolant to a greater extent than electrical unloose energy tin live produced. Because of depression clitoris per unit of measurement area inward the primary together with secondary coolant circuits cheap clitoris per unit of measurement area vessels tin live used. But this organisation has a disadvantage of using sodium. At high temperatures sodium becomes radioactive together with reacts amongst water. That’s why a intermediate Heat Exchanger (IHX) is used. It transfers estrus from Sodium to the secondary coolant NaK . This coolant goes to the steam generator heats the feed H2O to arrive at steam. Using liquid metallic equally coolants has certainly advantages. They possess got depression melting indicate together with high estrus transfer rate.
Fast Breeder Heat Reactor (FBR)
In this reactor no moderator is used. The primary fuel U235 is surrounded past times a blanket of fertile material. This cloth tin live U238 . Here fast electrons are absorbed past times U238 which produces Pu239 . Pu239 is sustainable to chain reaction. This reactor equally good uses ii metallic cooling organisation similar Sodium Graphite Reactor.
Candu Reactor
Candu refers to Canadian Deuterium Uranium reactor. It uses 99.8 % heavy H2O equally coolant together with moderator. Fuel is passed through the tubes. The heavy H2O is equally good passed though the channels surrounding the fuel tubes.
The tubes sense high internal pressure. While running the performance the reactor refueling takes place. The high temperature coolants are together with so passed to the steam generators which produces steam together with run the turbine.