Nuclear Power Plant

Nuclear Energy:
                            As large amounts of coal and petroleum are being used to produce energy,time may come when their reserves may not be able to meet the energy requirements. Thus there is tendency to seek alternate sources of energy. The discovery that energy can be liberated by the nuclear fission of material like uranium(U),plutonium(P),has opened up a new sources of power of great importance. The heat produced due to fission of U and Pu is used to heat water to generate steam which is used for running turbo-generator.
                            It has been found that one kilogram of U can produce as much energy as can be produced by burning 4500 tonnes of high grade coal.This shows that nuclear energy can be successfully employed for producing low cost energy in abundance as required by the expanding by the expanding and industrialising population of future.

Advantages:

Some of the advantages of Nuclear plants are:

• 1 kg of fuel of uranium gives energy equivalent 3,000 tonnes of high grade coal. Therefore in nuclear power plant the amount of fuel required is very less compared to conventional thermal power plant. Transportation and storage of the fuel is easier.
• Fossil fuel reserves depleting at higher rate. Therefore the cost of electricity production through coal and oil reserves increases per kilowatt hour compared to nuclear power plant, i.e, operational cost of nuclear plant is cheaper
• Nuclear power plants does not emit green house gases in to atmosphere unlike thermal power plants. Therefore nuclear power is clean and environmental friendly
• Nuclear power plants require little space compared to thermal power plant for the same MW output. Thermal plants require lot of space for coal storage, handling and ash pond. The fuel storage in nuclear plant requires less space and spent fuel coming out of the reactor is stored in small water tank.
• Nuclear fuel is available in plenty amount all over the world. Therefore fuel supply to plants will be continuing for hundreds of years.
• The output efficiency of nuclear plants is higher compared to thermal power plants and cost of electricity produced per unit is cheaper.
• Nuclear reactors such as breeder reactors will breed the fuel in reactor, over a period of time of operation of reactor the amount of fuel provided into the reactor will be equal to the fuel given output from the reactor. This is possible by converting fertile material to fissile material inside the reactor.
• Nuclear plants always operate as base load plants. Therefore plant availability 
• Disadvantages:
• Some of the disadvantages of nuclear plants are listed below:

  • In Nuclear plants safety is primary concern rather producing electricity. There is significant risk of leakage of radiation in case of any accident. The fission by products released are generally radio active and pollute the land, water, atmosphere and other natural resources. The land around the plant is considered as no man land for living for at least thousands of years
  • During shutdown of the reactor, decay heat is still produced from the reactor due to fission daughter products. This decay heat constitutes around 8 to 10% of the reactor power. For example consider reactor have a power of 500MW, decay heat generated from the reactor will be of the order of 40 to 50MW. This heat is to be continuously removed from the reactor else there is a chance of core melt down which can cause accident and radiation release. Modern plants are designed to remove decay heat through passive cooling if all the power supplies to the plant is lost which safeguard the reactor core
  • It requires large water mass for cooling purpose. Therefore the plant should be near to sea or river
  • Nuclear power plants always operate as base load plants and cannot support grid during transient conditions. In nuclear plant Turbine follows Reactor. Whatever may be the demand for electricity Nuclear plant does not worry. It produces the power proportional to the reactor power. Therefore it does not support electrical grid during transients. Because varying reactor power with respect to load will affect the safety and life of the plant.
  • It requires large area around the plant to be isolated from living (almost 5 kms radius)
  • State of art technology is required thereby increasing the cost and operators and other personnel should be highly skilled to tackle any situations
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