# Power Generation/Nuclear Power

Review: Lesson 4

The previous Lesson was about Diesel Power station. The student/User is expected to remember the following from the lesson 4.

• Basics:
• Arrangements:

Definition
components that make up a Diesel power station.
How this station measures up

Preview: Lesson 5

This Lesson is about Nuclear Power station. The student/User is expected to understand the following at the end of the lesson.

• Basics:
• Arrangements:

Definition
components that make up a Nuclear power station.
How this station measures up

 Figure 1:Kozloduy Nuclear Power Plant Kozloduy Nuclear Power Station, Bulgaria( Click on image to view full size image )

Introduction: Nuclear Power station

A Nuclear power station uses nuclear energy for generating electrical energy.

This power station is generally located far from populated areas. This kind of power station can be used to produce large amounts of electrical energy. In most countries these power stations are used as Base load power stations. This is because they can take several days to be warmed up and brought on-line.

Operation

Heavy elements such as Uranium (${\displaystyle U^{235}}$) or Thorium (${\displaystyle Th^{232}}$) are subjected to nuclear fission in a reactor to produce steam at high temperatures and pressure.

Steam runs a steam turbine which converts this energy into mechanical energy.

The turbine drives the alternator which converts mechanical energy into electrical energy.

Pros & Cons: what this power station presents

Small amounts of fuel required Fuel is expensive and hard to recover
Power plant requires less space Capital cost very high
Low running charges Erection & commissioning of plant requires great technical knowledge
Economical for producing bulk electrical energy Fission by-products are generally Radio-active & may cause nuclear pollution
Large available deposits of fuel around the world Maintenance costs are high
Reliability of operation Not suited for varying loads as reactor does not respond to fluctuations
Does not require large quantities of water for cooling Disposal of nuclear by-product is difficult & problematic

Future generations will want to depend more on this type of electricity generating power station (and other renewable energy sources), due to a fast increasing depletion of fuels(Coal). There are a number of construction projects currently underway for this kind of power station around the world.

 Figure 2: Nuclear power plant-pressurized water reactor Schematic ( Click on image to view full size image )

Constituents of Nuclear power station

Figure 2 shows a schematic of the general arrangement of a nuclear power station. The constituents of the schematic are labelled in the table below as follows:

 (1)--reactor block (2)--cooling tower (3)--reactor (4)--control rod (5)--support for pressure (6)--steam generator (7)--fuel element (8)--turbine (9)--generator (10)--transformer (11)--condenser (12)--gaseous (13)--liquid (14)--air (15)--air (humid) (16)--river (17)--cooling-water circulation (18)--primary circuit (19)--secondary circuit (20)--water vapor (21)--pump

Location of Nuclear power station: influencing factors

 Availablility of water: Sufficient water must be available for cooling, thus plant must be situated near a river or by sea-side. Disposal of waste: Waste produced is generally reactive, and thus must be disposed of properly to avoid health hazards. Waste must be disposed in deep trench or in sea away from shore.[factual?] Distance from populated areas: Must be far away from populated areas as there may be radio-active particles in the atmosphere near plant. However, the radio-activity released by a nuclear power plant is significantly less than a similar coal-powered plant.[1] Transportaion facilities: The site should be accessible by rail and(or) road for ease in transporting equipment & machinery.

Feasibility of this power station:

To be able to understand the reason why most contries are turning to the wide use of this kind of power station, we must consider the amount of energy produced by the fuel used by this kind of power station.

1 kg of Uranium (${\displaystyle U^{235}}$) can produce as much energy as 4500 Tons of high grade coal. This is more than enough to supply a metropolitan city for a month!

This schematic diagram must be properly understood. it is the basis upon which nuclear power station designs are done. The individual power station complexity may differ slightly to the shematic and yet over and above that will use the same principle.

 Figure 3: Animation of a pressurized Water reactor ( Click on image to view full size image )

## References

• This resource is prepared from Lecture notes by Thuvack.
• V.K Mehta & Rohit Mehta :- Principles of Power systems (1st ed.). S.CHAND .ISBN 81-219-2496-0