The layout of nuclear power plants comprises two major parts: The nuclear island and the conventional (turbine) island. The nuclear island is the heart of the nuclear power plant. On the other hand the conventional (turbine) island houses the key component which extracts thermal energy from pressurized steam and converts it into electrical energy. This device is called the turbine generator. The turbine generator is in the turbine building and contains most of the main components of the thermodynamic cycle. Only the steam generators are situated in the reactor building (the nuclear island).
Since the conventional power plants (e.g. fossil-fuel power plants) use very similar technology to convert thermal energy into electrical energy, this part of nuclear power plant is called “conventional island”. In comparison to conventional power plants the conventional island at nuclear power plants must fulfill the significantly stricter specification on quality assurance and control that applies to even conventional parts of the nuclear power plant due to the impact they may have on the nuclear systems.
The key components of conventional island are:
- Steam Turbine. A steam turbine is a device that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft.
- Generator. A generator is a device that converts mechanical energy of the steam turbine to electrical energy.
- Condenser. A condenser is a heat exchanger used to condense steam from last stage of turbine.
- Condensate-Feedwater System. Condensate-Feedwater Systems have two major functions. To supply adequate high quality water (condensate) to the steam generator and to heat the water (condensate) to a temperature close to saturation.
- Moisture Separator Reheater (MSR). The moisture separator reheaters are usually installed between the high pressure turbine outlet and the low pressure turbine inlets to remove the moisture from the high pressure turbine exhaust steam and to reheat this steam before admitted to the LP turbines.
- Cooling System. The primary function for cooling system in power plants is to cool the steam circuit so as to condense the low-pressure steam and recycle it. As the steam in the internal circuit condenses back to water, the surplus (waste) heat which is removed from it needs to be discharged by transfer to the air or to a body of water.
- Instrumentation and Control System (I&C). The instrumentation and control system serves as the central nervous system of a nuclear power plant.