Nuclear Reactor

A nuclear reactor is a machine that generates large-scale electricity using atomic energy derived from nuclear reactions on nuclear fuel.

Nuclear Fuel Example: Uranium-235,

• When Uranium-235 (U-235) is hit with slow neutrons, its nucleus splits in a process called nuclear fission.
• This fission produces Krypton-92 and Barium-141 nuclei, along with the release of 2 to 3 additional neutrons.
• These released neutrons can cause more U-235 nuclei to undergo fission, creating a chain reaction.

Nuclear fission (Chain reaction)

A chain reaction releases a large amount of nuclear energy. To prevent an explosion, the reaction must be carefully controlled by managing the speed and number of neutrons.

1. Core: Holds the nuclear fuel and produces the heat needed for energy generation. 
2. Nuclear Fuel: The primary material, such as Uranium-235 or Plutonium-239, that undergoes fission to release energy.
3. Moderator: Materials like graphite or heavy water are used as moderators to reduce the speed of neutrons and keep the reaction steady.
4. Controller: Rods made of boron, cadmium, or beryllium absorb excess neutrons to control the number of neutrons and prevent the chain reaction from escalating.
5. Coolant: It circulates through the core, absorbing heat and carrying it to the turbines.
6. Turbine: Converts the absorbed heat energy into mechanical energy.
7. Cooling Tower: Releases excess heat that cannot be converted or used.
8. Containment: A protective structure that isolates the reactor from the environment.

Nuclear reactor: Bhabha Atomic Research centre, Mumbai

The heat produced during nuclear fission is absorbed by water, which acts as a coolant. The heated water turns into steam, which drives turbines to produce electricity.

Nuclear reactors in India:

India has 22 operational nuclear reactors at eight different locations. The first nuclear reactor in India, named ‘Apsara,’ became critical on 4th August 1956 at the Bhabha Atomic Research Centre in Mumbai.

• India has significant reserves of Thorium-232 (Th-232).
• Indian scientists plan to use Th-232 to produce Uranium-233 (U-233) for future nuclear energy projects.