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Nuclear energy

Bomb

Nuclear energy:

    Nuclear energy is a powerful source of energy, generated during a nuclear reaction, by change in the nucleus of an atom. The source of nuclear energy is the mass of the nucleus and energy generated during a nuclear reaction is due to conversion of mass into energy (Einstein's Theory).

TWO WAYS TO OBTAIN NUCLEAR ENERGY:

1. Nuclear fission

2. Nuclear fusion

1.NUCLEAR FISSION

Nuclear fission reaction, the nucleus of a heavy radioactive element like uranium, plutonium or thorium splits up into smaller nuclei, when bombarded by low energy neutrons. A huge amount of heat is generated in this process, which is used in nuclear power plants to generate electricity.

2.NUCLEAR FUSION

Nuclear fusion reaction involves the combination or fusion of two light elements to form a heavier element and release uncontrollable energy. Thus it cannot be used to generate electricity, unlike fission reaction. Did you know that the sun’s energy is generated by nuclear fusion reaction? The heat and light that we get from Sun, is all due to the continuous reactions going on inside it. We can now imagine how much energy would be released in the nuclear fusion reaction, that it is the source of sun’s energy.

BRIEF INTRO:

Nuclear power is the use of sustained nuclear fission to generate heat and electricity.

Nuclear power plants provide about 5.7% of the world's energy and 13% of the world's electricity.  There were 439 nuclear power reactors in operation in the world, operating in 31 countries. 

Environmentalists for Nuclear Energy contend that nuclear power is a sustainable energy source that reduces carbon.

Just as many conventional thermal power stations generate electricity by harnessing the thermal energy released from burning fossil fuels, nuclear power plants convert the energy released from the nucleus of an atom via nuclear fission that takes place in a nuclear reactor. 

The heat is removed from the reactor core by a cooling system that uses the heat to generate steam, which drives a steam turbine connected to a generator producing electricity. 

LIFE CYCLE

A nuclear reactor is only part of the life-cycle for nuclear power. The process starts with mining (see Uranium mining). Uranium mines are underground, open-pit, or in-situ leach mines. 

The uranium ore is extracted, usually converted into a stable and compact form such as yellowcake, and then transported to a processing facility. The yellowcake is converted to uranium hexafluoride, which is then enriched using various techniques 

The fuel rods will spend about 3 operational cycles(typically 6 years inside the reactor).Then they will be moved to a spent fuel pool where the short lived isotopes generated by fission can decay away. After about 5 years in a spent fuel pool the spent fuel is radioactively and thermally cool enough to handle, and it can be moved to dry storage casks or reprocessed.

URANIUM:

Uranium is a fairly common element in the Earth's crust. Uranium is approximately as common as tin or germanium in Earth's crust, and is about 40 times more common than silver.  Uranium is a constituent of most rocks, dirt, and of the oceans. The fact that uranium is so spread out is a problem because mining uranium is only economically feasible where there is a large concentration.  The cost of nuclear power lies for the most part in the construction of the power station. Therefore the fuel's contribution to the overall cost of the electricity produced is relatively small, so even a large fuel price escalation will have relatively little effect on final price.


                                          Schematic diagram of nuclear reactor

Advantages  of nuclear energy:

  1. 1. Almost 0 emissions (very low greenhouse gas emissions). 
  2. 2.They can be sited almost anywhere unlike oil which is mostly imported. 
  3. 3.The plants almost never experience problems if not from human error, which almost never happens anyway because the plant only needs like 10 people to operate it.
  4. 4.A small amount of matter creates a large amount of energy.  A lot of energy is generated from a single power plant. 
  5. 5. Modern reactors have two to ten times more efficiency than the old generation reactors currently in use around the US. New reactor types have been designed to make it physically impossible to melt down.
  6. 6.As the core gets hotter the reaction gets slower, hence a run-away reaction leading to a melt-down is not possible.

  7. DISADVANTAGES of nuclear energy:

  8. 1.Nuclear plants are more expensive to build and maintain.
  9. 2. Waste products are dangerous and need to be carefully stored for long periods of time. The spent fuel is highly radioactive and has to be carefully stored for many years or decades after use. This adds to the costs.
  10. 3.There is presently no adequate safe long-term storage for radioactive and chemical waste .