There are two main types of nuclear reactors and here is how each of them works:
Pressurized Water Reactor
This type of a reactor functions by circulating heated water through tubes in generators, keeping this water under pressure so that it heats but doesn't boil. This water in the tubes turns the water inside the generator into steam and makes the turbine spin. These two water circuits that I described are both separate and closed.
1. The Fuel
The fuel used in a nuclear generator is Uranium, mostly Uranium - 235. After Uranium is mined it is manufactured into a shape looking bullet - like. They are about 2 cm long but produce the equivalent to the energy produced by 560l of oil. These small bullets are then stacked onto each other in a 2,5m long poke and assembled next to each other in an assembly, also known as the fuel rod assembly.
2. Reactor
The process that occurs in the reactor is basically a huge chain reaction. The Fuel, Uranium - 235 has a unique treat, that being that when an Uranium - 235 atom collides with a neutron, it splits. When it splits, more neutrons from that atom are released and collide with more Uranium - 235 atoms, that being the chain reaction that I've talked about. But where does the energy come from? When an atom splits, it is an exothermic reaction which means that it releases heat. The reaction is controlled by for example objects called control rods, these rods being stuck inside the other rods in the fuel rod assembly. By moving them, the technicians can affect whether they will absorb the atomic particles or if they will let the reaction occur.
3. Pressurizer
The heat that is produced in the reactor by the process that I described above is then transferred to the first water circuit, the primary coolant. The primary coolant although carrying the name coolant is heated to over 300°C. In this type of reactor, the pressuriser keeps the water from boiling.
4. Steam Generator
In a pressurized water reactor, the water passes through the tubes in the generator. The tubes in the generator are surrounded by the secondary water system also called the secondary coolant. This coolant receives the heat from the first coolant and it turns it into steam. The water in the two coolants does not mix, only the heat is being transferred.
5. Turbine
After the water is turned into steam, the steam is piped from the place where the reaction occurs to the turbine and spins it. The turbine is connected to an electricity generator. The turbine is connected to a magnet and as it spins, the magnet spins with it. The magnet that is connected to the turbine has one pole and it spins/rubs against another magnet with the opposite pole and creates electricity.
6. Condenser Coolant
Condenser Coolant is the last cooling agent in the process. After the steam runs through the turbine, it is cooled and condensed back into water. After this it is ready to be used over and over again in the steam generator.
7. Lake or Cooling Towers
There are two possible options in terms of how the steam is condensed and turned back into water. Some nuclear stations are designed to be standing next to a lake, using this lake as a coolant. The lake water flows through the condenser tubes and is than released and run through long canals back into the lake. The other type of power plants use cooling towers to cool the excess heat that the water absorbed. It is pumped to the top of the tower and allowed to fall down the structure, cooling off during the fall. There is also a set of fans at the top that pulls air through the falling water, helping with the cooling. After the water falls down it is ready to go through the whole process again.
Pressurized Water Reactor
This type of a reactor functions by circulating heated water through tubes in generators, keeping this water under pressure so that it heats but doesn't boil. This water in the tubes turns the water inside the generator into steam and makes the turbine spin. These two water circuits that I described are both separate and closed.
1. The Fuel
The fuel used in a nuclear generator is Uranium, mostly Uranium - 235. After Uranium is mined it is manufactured into a shape looking bullet - like. They are about 2 cm long but produce the equivalent to the energy produced by 560l of oil. These small bullets are then stacked onto each other in a 2,5m long poke and assembled next to each other in an assembly, also known as the fuel rod assembly.
2. Reactor
The process that occurs in the reactor is basically a huge chain reaction. The Fuel, Uranium - 235 has a unique treat, that being that when an Uranium - 235 atom collides with a neutron, it splits. When it splits, more neutrons from that atom are released and collide with more Uranium - 235 atoms, that being the chain reaction that I've talked about. But where does the energy come from? When an atom splits, it is an exothermic reaction which means that it releases heat. The reaction is controlled by for example objects called control rods, these rods being stuck inside the other rods in the fuel rod assembly. By moving them, the technicians can affect whether they will absorb the atomic particles or if they will let the reaction occur.
3. Pressurizer
The heat that is produced in the reactor by the process that I described above is then transferred to the first water circuit, the primary coolant. The primary coolant although carrying the name coolant is heated to over 300°C. In this type of reactor, the pressuriser keeps the water from boiling.
4. Steam Generator
In a pressurized water reactor, the water passes through the tubes in the generator. The tubes in the generator are surrounded by the secondary water system also called the secondary coolant. This coolant receives the heat from the first coolant and it turns it into steam. The water in the two coolants does not mix, only the heat is being transferred.
5. Turbine
After the water is turned into steam, the steam is piped from the place where the reaction occurs to the turbine and spins it. The turbine is connected to an electricity generator. The turbine is connected to a magnet and as it spins, the magnet spins with it. The magnet that is connected to the turbine has one pole and it spins/rubs against another magnet with the opposite pole and creates electricity.
6. Condenser Coolant
Condenser Coolant is the last cooling agent in the process. After the steam runs through the turbine, it is cooled and condensed back into water. After this it is ready to be used over and over again in the steam generator.
7. Lake or Cooling Towers
There are two possible options in terms of how the steam is condensed and turned back into water. Some nuclear stations are designed to be standing next to a lake, using this lake as a coolant. The lake water flows through the condenser tubes and is than released and run through long canals back into the lake. The other type of power plants use cooling towers to cool the excess heat that the water absorbed. It is pumped to the top of the tower and allowed to fall down the structure, cooling off during the fall. There is also a set of fans at the top that pulls air through the falling water, helping with the cooling. After the water falls down it is ready to go through the whole process again.
Boiling Water Reactor
In a Boiling water reactor, the difference is that the water is allowed to turn into steam and push the turbine. This means that the two circuits are connected but the water can still be used again, just like in a PWR reactor.
In a Boiling water reactor, the difference is that the water is allowed to turn into steam and push the turbine. This means that the two circuits are connected but the water can still be used again, just like in a PWR reactor.