Nuclear Power Plant and Nuclear Energy

All articles are written in simple language to visualize Mechanical Engineering. Let’s explore!

Nuclear Power Plant and Nuclear Energy

T he nuclear power plant is the current trend in all kinds of power plants. The energy from the nuclear power plant or any nuclear action is known as Nuclear Energy. The population is increasing day by day and the demand for energy is also increasing gradually. In conventional power plants, coal, gas, oil, etc. are widely used. These sources are limited.

Hence, to avert this limitation as well as to meet the current energy demands, nuclear power plants are the best choice.

So, let’s explore, nuclear power plant!

Nuclear Power Plant 

The nuclear power plant, the name itself implies the heat source from the nuclear reactor. This nuclear plant requires a very small mass as input sources compare to conventional fuels.

In the nuclear power plant, nuclear fission happens which gives a huge amount of energy compare to conventional fuels. Fission means the splitting of uranium. Only 1 kg of Uranium can give the energy equivalent to 3100tons coal or 1700 tons of oil by nuclear fusion.

nuclear power plant
Nuclear power plant

What is Nuclear Plant?

Nuclear Power Plant Definition

The nuclear power plant is one kind of power plant which undergoes the nuclear fusion process and generates electricity.

  • Nuclear power plants convert atomic-level energy into normal usable power.
  • It works in the ranking cycle and heat is produced by nuclear reactors.

History of Nuclear Power Plant

Obninsk Nuclear Power Plant is the world’s first nuclear power plant. It is in Obninsk of the Soviet Union and was started to operate in 1954

Nuclear Energy

Nuclear Fission Reaction

Fission means splitting. Nuclear fission means the splitting of atoms in the nuclear reactors. Here, a huge amount of heat energy is released due to this reaction.

Making this reaction and controlling it is the main objects in nuclear power plants.

Uranium, used as fuels, comes with pellets and kept within metal tubes. These metal tubes are known as fuel rods.

nuclear energy nuclear fission reaction
Nuclear energy nuclear fission reaction

Many fuel rods are bundled to make a ready fuel and kept inside the reactor core. Water is used as a coolant and the fuel rods are immersed in the water.  Nos of fuel rods depends on the capacity requirements of the nuclear power plant.

Uranium splits into neutrons and nucleus and produced a huge amount of heat.

Type of Nuclear Power Plants

Nuclear power plants are classified based on the type of nuclear reactors are used. There are mainly two types of nuclear reactors and based on that 80% of the world’s 450 nuclear power plants are built.

  • Pressurized water reactor (PWR)
  • Boiling water reactor (BWR)

Pressurized water reactor (PWR)

Pressurized water reactor is the most common type of reactor used in nuclear power plants. In this reactor, two circuits are used to produce steam:

  • First circuit: Water is extremely heated by the reactor core and fed to the steam generator
  • Water is further heated and transferred into steam in a steam generator

 Boiling water reactor (BWR)

Boiling water reactors is also widely used to generate power in a lot of places. Here, only on circuit instead of two no’s’, with respect to PVR.

Apart from these two, there are few other types of nuclear power reactors;

Nuclear Power Plant Main Components

In this session, let’s discuss the most widely used pressurized water reactor type nuclear power plant for examples. There are various components in the Nuclear Power Plant, however, brief details for the main components are described for better understanding.

nuclear power plant parts components
Nuclear power plant parts components
  • Nuclear Reactor
  • Coolant circulating pump
  • Heat Exchanger
  • Feed pump
  • Condenser
  • Turbine and
  • Generator

Nuclear Reactor

The nuclear reactors are the primary components in all kinds of nuclear power plants. It is simply the heart of the nuclear power plant. We have seen the thermal power plant, where the boiler is used to produce heat. Coal is normally used as fossil fuels to generate electricity.

In a nuclear power plant, nuclear reactors are used as boilers like thermal power plants, and uranium is used as fuels to generate electricity.

Nuclear chain reaction i.e., nuclear fusion happens in a nuclear reactor.  This fusion process produces heat. This heat is transferred from the nuclear reactor core to coolants i.e. fluid. Water is commonly used as a coolant.

Now the water takes the heat and circulated to the steam generator by reactor coolant pumps to produce steam.

There are several components common to most types of reactors:

  • Containment structure
  • Fuel
  • Moderator
  • Coolant
  • Reactor coolant pump
  • Control rods
  • Steam generator
  • Steam line
nuclear reactor energy
Nuclear reactor energy

Let’s try to understand the individual parts of the reactor, to have a brief idea:

Containment structure

It is a rigid structure that houses the reactor, steam generator, coolant system, and all related components.

  • Containment structure prevents the Leak of radiations, as well as neutrons, which are fully prevented by the containment structure.
  • Safety aspects
  • It is normally made of concrete; however, it can be of high-grade steel or lead also based on applications.

Fuel Commonly used

Uranium is used so that fusion takes place. Uranium is the source of energy as well as neutrons so that chain reaction will be continued. It looks like cylindrical pills come within metallic rods.


Moderator is used to slow down the generation of neutrons. It reduces the fission process as well as chain reactions.


In a nuclear reactor, the pressurizer is an important part to control pressure. It is placed in the primary coolant circuit.

Control of steam production and balancing of the liquid stage and the steam stage is done by the pressurizer.

Cooling water

The heat generated from the fission process is transferred to this cooling water or coolant.

Reactor coolant pump

Hot water from the reactor core needs to be circulated to the steam generator. This circulation is done by coolant circulation pump or reactor coolant pumps or RCV.

  • Transfer coolant to the steam generator
  • Transfer the heat produced in the reactor
  • Increased water velocity

Control rods

Control rods are able to absorb neutrons and control the numbers as well.

  • These are made of boron carbide normally
  • It controls the reaction by controlling the numbers of neutrons
  • It keeps the nuclear reactor stable
  • It can stop the reaction if required

Steam generators

It is basically a heat exchanger. Hot water from the primary circuit comes in this steam generator and produces steam.

  • It has inverted U-shaped tubes,
  • gives all its energy to the secondary circuit and becomes water steam.
  • It transfers heat through metal conduction
  • The pressure becomes low, and due to this low-pressure hot water converts into steam,

Nuclear reactors are used not only for power generation, it used also for,

  • Propulsion of ships,
  • Satellites
  • Aircrafts
  • Medical and research purposes
  • Plutonium manufacturing


Steam from the steam generator comes into the turbine through a steam line or steam pipe.

  • Steam has high pressure and it hits the vanes of the turbine blades and forced it to rotate the turbine.
  • Speed of the turbine increases drastically
  • In this case, kinetic energy converted into rotational motion or mechanical energy.
  • High-pressure steam is expanded in the turbine and produce work.
  • The turbine shaft is connected to a generator axis.


A condenser is used as a heat exchanger and it consists of a set of tubes. Exhaust steam from the turbine is required to cool for further use.

  • In the condenser, steam is cooled below the boiling point temperature and steam changed into water.
  • When steam converts into the water, a vacuum will be created and conversion from steam to water will be first.
  • This circulation is done by circulating pumps.

Cooling tower

The temperature of condenser water is high, and it is required to cool. The cooling tower cools the water and circulate back to the condenser through condensate extraction pumps.

  • Cooling tower rejects the waste from hot water to the atmosphere
  • This loss is due to evaporation and it is around 2%


The generator is used to produce electrical energy from mechanical energy, and we got the power output.

Nuclear Power Plant Diagram

The nuclear power plant is explained here with a simple diagram. This plant works almost the same as thermal power plants except for the nuclear reactor.

Look at the diagram,

diagram of nuclear power plant reactor
Diagram of nuclear power plant reactor

How does nuclear power plant works

Let’s see how nuclear plant works?

Working Basic of Nuclear Plant

Nuclear Reactor, Reactor Coolant Pumps, Steam generator or Heat Exchanger, Feed Pump, Condenser, Turbine, and Generator are the main parts of nuclear power plant.

The uranium fission takes place inside the nuclear reactor. It releases a large amount of energy that heats the coolant water circulating at a very high pressure. This water is transported via the primary circuit to a heat exchanger (steam generator) that produces water steam.

We have already studied atoms. It consists nucleus at the Centre and electrons in the orbits. The nucleus is packed and it is the heaviest matter in the atoms. Nucleus consists of neutrons and protons.

Uranium is the heaviest matter and it has 92 protons. Due to the large volume, the atomic force is comparatively less.

Working Principle


Chain Reaction

Neutrons are bombarded on the uranium; uranium atoms will be split, and more neutrons will be released. Hence, fission starts. These neutrons will again collide with uranium’s atoms and release neutrons again. This release, again and again, continues chai reaction.


Control with control rods

There are many control rods to control the chain reaction. Control rods are able to absorb the neutrons which stop the reaction or control.


Heat transfer to coolant

Due to fission, huge heat energy is released. A coolant i.e water is circulated, and heat transfer happens between the reactor and the coolant.

Water is becoming hot and the temperature of the water becomes high.


Production of steam

The coolant is transferred to the steam generator through reactor coolant pumps. Heat exchange happens and hot water changed into high-pressure steam.


Rotation of Turbine

The steam from the steam generator enters the turbine and hits the blade. Due to the high-pressure turbine start to rotate.


Condenser cooling

Exhaust steam is transferred to the condenser and form hot water. This hot water is circulated to the cooling tower and cooled through circulating pumps.


Power Generation

Due to the rotation of the turbine, the connected shaft with the generator also rotates. A magnetic field is created, and electricity is produced.

Pros and cons of nuclear power

Nuclear Energy Advantages

There are many advantages of nuclear power plants as well as nuclear energy,

  • The nuclear power plant has less carbon footprints and it is a very low-carbon energy producers.
  • It is a clean energy source.
  • It doesn’t create greenhouse gas methane or CO2 etc. like other power plants.
  • The amount of fuel consumption is very less in comparison to coal or oil or gas-based power plants.
  • Due to less fuel consumption, fuel handling is very easy and transportation cost is also low.
  • A nuclear power plant can fulfill the high-power demand increased day by day.
  • Nuclear energy can fulfill the energy demand within the shortest time.
  • The efficiency of a nuclear power plant is high. In full load condition, it’s efficiency can be 80-90%
  • Space requirements for the Nuclear Power Plant are very less in comparison with conventional power plants.
  • The requirement of coolant or water is very less with respect to conventional power plants.
  • The nuclear power plant is very compact.
  • Easy maintenance.
  • The nuclear power plant is highly reliable
  • Best cost-effective solution for producing energy.
  • The produced electricity is cheaper than electricity generated by conventional power plants.
  • Energy production doesn’t depend on adverse weather conditions.
  • No adverse effect on surroundings, habitats.
  • Very less amount of water is required.
  • A very high capacity plant can be installed.
  • Nuclear power plants can produce hydrogen which may be used in vehicles as an emission-free alternative engine fuel.
  • Help to grow the infrastructure as well as the economy of nations.

Disadvantages of nuclear energy

There are few disadvantages also of Nuclear Power Plant as well as nuclear energy

  • The fuel is highly radioactive; hence, it is really very dangerous to transport or handle it.
  • Another big problem is waste disposal. Since the waste is radioactive, it always harms the environment as well as the habitats.
  • Impact on the heath of the workers in nuclear power plants.
  • The initial cost to set up a nuclear power plant is very high.
  • The efficiency of nuclear power is comparatively less for varying load conditions.
  • High maintenance cost.
  • Nuclear energy is not renewable, hence, it has also a limited source. Although the fuel amount is very less, the impact on the resource in a long time may come.
  • Accidents in nuclear power plant makes always drastic impacts. The Chernobyl accident is an example of it.
  • Safety in a nuclear power plant is very critical, any minor ignorance may cost very high.

Safety Measures at Nuclear Power Plants

All nuclear power plants have a number of safety measures to prevent

  • Any kind of leakage of radioactivity materials
  • High precision design
  • Multiple safety factors
  • Special design considerations for reactors
  • Proper design margin
  • Follow all safety standards as well as design standards
  • Special system to handle the radioactive leakage
  • Avoid human errors & alternate safety considerations.
  • Proper disposal of radioactive waste disposal.

Application of Nuclear Energy or Nuclear Power Plants

There are various application of nuclear energy, 

  • A single nuclear power plant can give energy which is equal to the energy of many other conventional power plants.
  • It can be used in many industrial applications, like oil & gas, Infracture development, seawater desalination, refrigeration & air conditioning, medicine, hydrology, mining, etc.
  • Energy supply to vehicles

Nuclear Power Plants at a Glance

10% of the world’s electricity. About 50 power reactors are currently being constructed in 15 countries

As of March 2018, India has installed a total of 7 nuclear power plants including 22 Nuclear reactors of a total of 6780 MW capacity.  In addition, India has already planned to install more. These nuclear plants are operated by Nuclear Power Corporation of India Limited (NPCIL).

Plants are located;

  1. Tarapur, Maharashtra
  2. Rawatbhata, Rajasthan
  3. Kudankulam, Tamil Nadu
  4. Kaiga, Karnataka
  5. Kakrapar, Gujarat
  6. Kalpakkam, Tamil Nadu
  7. Narora, Uttar Pradesh


Hence, we have got the basic idea of nuclear power plant along with its basics, diagrams, working principles. Any doubt, feel free to contact.



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