CBSE Class 10 Answered
A nuclear power plant produces electricity with the help of a nuclear fuel (uranium-235 or plutonium-239) through a self-sustaining fission chain reaction (nuclear reactions) that releases energy at a controlled rate.
Nuclear fission reaction is used to generate electricity in nuclear power plants. Most of the power plants use uranium 235 as fuel to produce heat.
In a nuclear power plant, the fission of nuclear fuel, uranium 235 is carried out in a steel pressure vessel of the nuclear reactor. The enriched uranium 235 rods are inserted in a core made of graphite blocks inside the reactor. This graphite is called as the moderator because it slows down the speed of neutrons for an effective nuclear fission. In between the uranium rods, boron / cadmium rods are also inserted which are called as the control rods.These rods absorb excess neutrons and controls the fission reaction. The nuclear reactor consisting of all the above ( nuclear fuel, control rods, moderator,etc.) is enclosed in a chamber having thick walls to absorb the nuclear radiations. Heavy water (or liquid sodium or carbon dioxide) is used as a coolant to transfer the heat produced in the reactor.
The controlled fission of uranium 235 inside the reactor produces a lot of heat energy . The coolant is pumped into the reactor by using a pipe. The coolant absorbs the heat energy released during the nuclear reaction and this extremely hot coolant passes through the coil of a heat exchanger containing water . The water absorbs heat from the hot coolant and boils to form steam. This hot steam at high pressure is passed to a chamber having a turbine .The pressure of steam makes the turbine rotate. The shaft of the turbine is connected to a generator. When the turbine rotates,its shaft also rotates and drives the generator. The generator thus produces electricity.