Swati Talwar


nuclear reactor meaning

nuclear fission

nuclear reactor diagram

types of nuclear reactors

Nuclear Reactor Study Guide

A nuclear reactor is a machine that helps control the nuclear fission reaction or nuclear fusion reactions.


reactor Source

Do you know what happens in a nuclear power plant? A nuclear plant is a place where nuclear reactions take place to emit energy. This energy is used for heating, producing electricity, etc. The source of energy in nuclear power reactors is uranium fuel. Since we know very little about nuclear reactors, let us learn more in detail about them!


Nuclear reactors can be defined as the device which is used to manage the nuclear fission chain reactions. Nuclear reactors are the main parts of any nuclear plant. They help to control and contain the nuclear chain reactions taking place in the nuclear plant. 

The reaction takes place in the physical process that is known as fission, and the heat generated from the reaction is used to make steam which helps to rotate the turbine to generate electricity. The nuclear power plant is considered the largest source of production of dependable carbon-free electricity.

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It helps to control the nuclear fission reaction. The various  components of a nuclear reactor are as follows:

  • Fuel 
  • Moderator in a nuclear reactor
  • Nuclear reactor control rods
  • Pressure tubes
  • Steam generators
  • Coolant in the nuclear reactor
  • Containment



The different types of nuclear reactors are as follows:

  • Pressurized water reactor (PWR)
  • Advanced gas-cooled reactor (AGCR)
  • Boiling water reactors (BWR)
  • Light water graphite-moderated reactor (LWGR)
  • Fast neutron reactor (FNR)


  •  As the coolant of the nuclear reactor, the most common is water. The water is also heated to form steam to rotate the turbines. 
  • Later it is condensed back to form water so that it can be used again.
  • It is considered the most pollution-free energy source.


Q. What are the four types of nuclear reactors?

Four types of nuclear reactors are as follows:

  • Pressurized water reactor (PWR)
  • Advanced gas-cooled reactor (AGCR)
  • Boiling water reactors (BWR)
  • Light water graphite-moderated reactor (LWGR)

Q. How many nuclear reactors are there in India?

There are 22 nuclear reactors in India with a total capability of 6780MW operation. 

Q. Which country has the most nuclear reactors?

The united states of America has the most nuclear reactors. They hold 96 nuclear plants with a capacity of 97,565MW.  

Q. What is the working principle of nuclear reactors?

Nuclear reactors work on the principle of nuclear fission. In this process, a heavy atomic nucleus ends up splitting into two smaller components. The nuclear components are in a very excited state and emit other subatomic particles, neutrons, and photons.

We hope you enjoyed studying this lesson and learned something cool about Nuclear Reactors! Join our Discord community to get any questions you may have answered and to engage with other students just like you! We promise, it makes studying much more fun!😎


  1. Nuclear Power Reactors: https://world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-power-reactors/nuclear-power-reactors.aspx. Accessed 19th April 2022.
  2. Nuclear 101: https://www.energy.gov/ne/articles/nuclear-101-how-does-nuclear-reactor-work Accessed 19th April 2022.
  3. Nuclear Reactor: https://www.britannica.com/technology/nuclear-reactor Accessed 19th April 2022.