Explain the principle and working of a nuclear reactor with the help of a labelled diagram.

NUCLEAR REACTOR A nuclear reactor is a device to produce nuclear energy based on controlled nuclear chain reaction. Principle of nuclear reactor: It works on the principle of achieving controlled chain reaction of Uranium enriched with U 235 and as a result generating huge amount of energy. The chain reaction is controlled slowing down the fission neutrons to thermal neutrons by using a moderator. The reaction rate is maintained controlled rods that can absorb neutrons Working: 1. Neutron induced fission releases energy plus extra fast neutrons. 2. Fast neutrons are slowed down by a “moderator” such as water or graphite, allowing chain reaction to occur. 3. Chain reaction is controlled by controlling the condition of the moderator, or by use of neutron absorbing materials (e.g. cadmium control rods) 4. Heat is removed by some form of heat exchanger where it is used to run a heat engine.