Uranium has three major isotopes, U233, U235 and U238, out of which the last two are naturally occurring. U233 and U235 are fissionable materials, i.e., they can be split by bombarding with neutrons. U233 can be produced from Thorium, which is a non-fissile material and is known as fast breeding. Plutonium 239 can be produced from U238, but Plutonium is not a naturally occurring element and is fissile.Fission is a nuclear reaction, which splits the Uranium atom into two or more small atoms on bombardment with a neutron. The combined mass of the split atoms is slightly less than that of the Uranium atom and the loss of this small mass is known as mass defect. According to Einstein's famous theory of relativity formula, E = mc{+2} where E = Energy, m = mass, and c = velocity of light, this mass to energy conversion takes place.
The released thermal energy is absorbed by the coolant of the reactor and in a heat exchanger the coolant gives its heat to water and steam is produced. The steam drives a turbine, which is coupled to a generator. This is how electricity is produced. On bombardment by a neutron, an uranium atom releases three neutrons out of which two are absorbed by a moderator in the reactor and only one is allowed to continue the reaction. The moderator can be a control rod and the coolant itself sometimes serves as the moderator. This type of arrangement is known as controlled chain reaction. Many types of reactors are in use today.
Source : The Hindu
The released thermal energy is absorbed by the coolant of the reactor and in a heat exchanger the coolant gives its heat to water and steam is produced. The steam drives a turbine, which is coupled to a generator. This is how electricity is produced. On bombardment by a neutron, an uranium atom releases three neutrons out of which two are absorbed by a moderator in the reactor and only one is allowed to continue the reaction. The moderator can be a control rod and the coolant itself sometimes serves as the moderator. This type of arrangement is known as controlled chain reaction. Many types of reactors are in use today.
Source : The Hindu