nuclear power :

Nuclear power is the use of nuclear reactions that release nuclear energy[5] to generate heat, which most frequently is then used in steam turbines to produce electricity in a nuclear power plant. The term includes nuclear fission, nuclear decay and nuclear fusion. Presently, the nuclear fission of elements in the actinide series of the periodic table produce the vast majority of nuclear energy in the direct service of humankind, with nuclear decay processes, primarily in the form of geothermal energy, and radioisotope thermoelectric generators, in niche uses making up the rest.

Owing, fundamentally, to the control on the power or heat increase, that is inherent to the slow delayed critical fission process,[6] Fission-electric power stations and engines have and continue to be built, as an alternative to the dominant fossil-fuel power systems of the world. Fission-electricity is one of the leading low carbon power generation methods of producing electricity, and in terms of total life-cycle greenhouse gas emissions per unit of energy generated, has emission values lower than renewable energy when the latter is taken as a single energy source.[7][8] A 2014 analysis of the carbon footprint literature by the Intergovernmental Panel on Climate Change (IPCC) reported that the embodied total life-cycle emission intensity of fission electricity has a median value of 12 g CO2eq/kWh which is the lowest out of all commercial baseload energy sources.[9][10] This is contrasted with coal and fossil gas at 820 and 490 g CO2 eq/kWh.[9][10] From the beginning of fission-electric power station commercialization in the 1970s, nuclear power prevented the emission of about 64 billion tonnes of carbon dioxide equivalent that would have otherwise resulted from the burning of fossil fuels in thermal power stations.[11]

There is a social debate about nuclear power.[12][13][14] Proponents, such as the World Nuclear Association and Environmentalists for Nuclear Energy, contend that nuclear power is a safe, sustainable energy source that reduces carbon emissions.[15] Opponents, such as Greenpeace International and NIRS, contend that nuclear power poses many threats to people and the environment.[16][17][18] Far-reaching fission power reactor accidents, or accidents that resulted in medium to long-lived fission product contamination of inhabited areas, have occurred in Generation I and II reactor designs. These include the Chernobyl disaster in 1986, the Fukushima Daiichi nuclear disaster in 2011, and the more contained Three Mile Island accident in 1979.[19] There have also been some nuclear submarine accidents.[19][20][21] In terms of lives lost per unit of energy generated, analysis has determined that fission-electric reactors have caused fewer fatalities per unit of energy generated than the other major sources of energy generation. Energy production from coal, petroleum, natural gas and hydroelectricity has caused a greater number of fatalities per unit of energy generated due to air pollution and energy accident effects.[22][23][24][25][26][27]

As of 2017, the International Atomic Energy Agency states that 60 reactors, mostly of Generation III reactor design, are under construction around the world, with the majority in Asia.[28] Collaboration on research & developments towards greater passive nuclear safety, efficiency and recycling of spent fuel in future Generation IV reactors presently includes Euratom and the co-operation of more than 10 permanent countries globally.

nuclear power plant :

A nuclear power plant (nuclear power station) looks like a standard thermal power station with one exception. The heat source in the nuclear power plant is a nuclear reactor. As is typical in all conventional thermal power stations the heat is used to generate steam which drives a steam turbine connected to a generator which produces electricity.
Steam turbine is a common feature of all thermal power plants. Steam Turbine was invented in 1884 by Sir Charles Parsons, whose first model was connected to a dynamo that generated 7.5 kW (10 hp) of electricity. Exceptional feature of the nuclear power plant is the nuclear reactor and its safety and auxiliary systems.


Components of a nuclear power plant
The key components common to most nuclear power plants are:

Nuclear Reactor. A nuclear reactor is a key device of nuclear power plants. Main purpose of the nuclear reactor is to initiate and control a sustained nuclear chain reaction.
Steam Generators. Steam generators are heat exchangers used to convert feedwater into steam from heat produced in a nuclear reactor core. They are used in pressurized water reactors (PWR) between the primary and secondary coolant loops.
Pressurizer. Pressure in the primary circuit is maintained by a pressurizer, a separate vessel that is connected to the primary circuit (hot leg) and partially filled with water which is heated to the saturation temperature (boiling point) for the desired pressure by submerged electrical heaters. Temperature in the pressurizer can be maintained at 345 °C (653 °F), which gives a subcooling margin (the difference between the pressurizer temperature and the highest temperature in the reactor core) of 30 °C.
Reactor Coolant Pumps. Reactor coolant pumps are used to pump primary coolant around the primary circuit. These pumps are powerful, they can consume up to 6 MW each and they can be used for heating the primary coolant before a reactor start-up.
Safety Systems. According to the U.S. Nuclear Regulatory Commission primary objectives of nuclear reactor safety systems are to shut down the reactor, maintain it in a shutdown condition and prevent the release of radioactive material. Reactor safety systems consist of:
Reactor Protection Systems
Essential service water system
Emergency core cooling systems
Emergency power systems
Containment systems
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.
Electricity Production
The heat is produced by fission in a nuclear reactor and passes into the primary cooling water. This heat, deposited in the cooling water, is conducted to the steam generators situated in the containment building. Steam generators produce high pressurized steam. The pressurized steam is then usually fed to a multi-stage steam turbine. Steam turbines in western nuclear power plants are among the largest steam turbines ever.


generation of nuclear energy :

Nuclear power plants currently operate in 31 countries. Most are in Europe, North America, East Asia and South Asia. The United States is the largest producer of nuclear power, while France has the largest share of electricity generated by nuclear power. In 2010, before the Fukushima Daiichi nuclear disaster, it was reported that an average of about 10 nuclear reactors were expected to become operational per year, although according to the World Nuclear Association, of the 17 civilian reactors planned to become operational between 2007 and 2009, only five actually came on stream.[3] Global nuclear electricity generation in 2012 was at its lowest level since 1999.[4][5]

China has the fastest growing nuclear power program with 28 new reactors under construction,[6] and a considerable number of new reactors are also being built in India, Russia and South Korea. At the same time, at least 100 older and smaller reactors will "most probably be closed over the next 10–15 years".[3]

Some countries operated nuclear reactors in the past but have currently no operating nuclear plants. Among them, Italy closed all of its nuclear stations by 1990 and nuclear power has since been declared illegal in a referendum. Lithuania, Kazakhstan and Armenia are planning to reintroduce nuclear power in the future.

Several countries are currently operating nuclear power plants but are planning a nuclear power phase-out. These are Belgium, Germany, Spain, and Switzerland. Other countries, like Netherlands, Sweden, and Taiwan are also considering a phase-out. Austria never started to use its first nuclear plant that was completely built.

Due to financial, politic and technical reasons, Cuba, Libya, North Korea, and Poland never completed the construction of their first nuclear plants, and Australia, Azerbaijan, Georgia, Ghana, Ireland, Kuwait, Oman, Peru, Singapore, and Venezuela never built their planned first nuclear plants
Of the 31 countries in which nuclear power plants operate, only France, Slovakia, Ukraine, Belgium, and Hungary use them as the source for a majority of the country's electricity supply, although many other countries still have significant amounts of nuclear power generation capacity.[10] According to the World Nuclear Association, a nuclear power advocacy group, over 45 countries are giving "serious consideration" to introducing a nuclear power capability, with Belarus, Iran, Jordan, Turkey, the United Arab Emirates and Vietnam at the forefront.[11] China, India and South Korea are pursuing ambitious expansions of their nuclear power capacities, with China aiming to increase capacity to at least 80 GWe by 2020, 200 GWe by 2030 and 400 GWe by 2050.[12] South Korea plans to expand its nuclear capacity from 20.7 GWe in 2012 to 27.3 GWe in 2020 and to 43 GWe by 2030.[13] India aims to have 14.6 GWe nuclear power generation capacity by 2020 and 63 GWe by 2032 and to have 25% of all electricity supplied by nuclear power by 2050.

nuclear power in india :

Renewable energy in India has overtaken nuclear power as the country seeks carbon-free sources of energy to balance its reliance on coal.
Renewable energy generation in India is higher than its nuclear power generation and is growing at a much faster pace because it is cheaper and quicker to install. The cost of renewable energy is now lower than the cost of nuclear power and does not come with attendant risks, such as last week’s radioactive fuel leak in Gujarat.
Renewable energy generation in India was 61.8 billion units, versus 36.1 billion units of nuclear power generation during the financial year 2014-'15. Renewable energy accounted for 5.6% of electricity generated in India, against 3.2% for nuclear power.
Renewable energy has been growing at a faster pace than nuclear power over two years. During 2013-'14 and 2014-'15, renewable energy grew at 11.7% and 16.2%, respectively, while nuclear power growth has been almost flat over the same period.