Read the link below.
One type of nuclear reactor is the pressurized water reactor (PWR). In a PWR, the heat generated by nuclear fission in the reactor core is transferred to water, which circulates through the core to create steam that drives turbines to produce electricity.
Nuclear fission, not to be confused with fusion.
In a nuclear reactor, energy is released through a process of nuclear fission. This produces heat that is used to boil water and produce steam, which then drives a turbine connected to a generator. As the turbine spins, it generates electricity.
There are two primary design styles of fission reactors to produce electricity. Pressurized, and Boiling water reactors.
A nuclear reactor is an assembly of fuel elements (uranium usually), a moderator which can be ordinary water, heavy water, or graphite, and control rods. The reactor is made to reach criticality when uranium fuel will produce a steady power output as a result of nuclear fissions which release heat. The heat is used to produce steam which feeds a conventional steam turbine/generating unit.
The reason for having many reactors is because you can produce more electrical energy from them. Also Japan use BWR type reactors(Boiling Water Reactor) which are not as efficent as a more commonly used PWR reactor(Pressurized Water Reactor).
Heat produced I'm a nuclear reactor turns water into steam that moves a massive turbine that my moving, produces energy. Water is then cooled and heated again to produce steam. Process keeps respecting itself.
Heavy water is expensive to produce and can be hazardous to the environment if leaked in large quantities. It can contaminate water sources and harm aquatic life. In addition, heavy water is used in nuclear reactors, and a leak could potentially impact the safety and operation of the reactor.
The moderator used in the nuclear reactor at Madras Atomic Power Station in Kalpakkam is usually heavy water (deuterium oxide) or light water (ordinary water). These moderators are important for slowing down neutrons produced during nuclear fission reactions to sustain the chain reaction in the reactor.
In a nuclear reactor, the generator's primary function is to convert the thermal energy produced from nuclear fission into electrical energy. The reactor generates heat, which is used to produce steam from water. This steam drives turbines connected to the generator, which then produces electricity. Essentially, the generator transforms the kinetic energy from the turbine into usable electrical energy for distribution.
This is the Candu type, which was uniquely developed in Canada to use heavy water moderator and natural uranium fuel
Tritium is formed by the capture of neutrons by deuterium (heavy hydrogen) which is in the heavy water in the moderator and coolant.