Nuclear energy is another non-renewable source that has gained popularity in the last few years. With the depleting resources and high energy demand the world is looking towards the nuclear energy as its source that is created from the nucleus of an atom. Nuclear energy, as the term says, is released from the very nucleus of an atom. This happens as a result of its mass being converted to energy. Even though nuclear power is safer
than burning electricity for fossil fuels, it is still a hazard to our health and the environment.
Nuclear power is produced through two different processes: Nuclear Fission and Nuclear Fusion.
Nuclear Fission :
Nuclear fission is the process of releasing the atomic energy by splitting the nucleus thus creating two products of roughly half the mass of the original. A nuclear reactor splits the nuclei of uranium atoms, creating large amounts of energy. This process also creates radioactive waste and radiation, which can contaminate the environment. Nuclear fission is the physical process responsible for all types of power generation, including that used in both nuclear weapons and nuclear power plants.
Nuclear Fusion :
Nuclear fusion is the energy source of the future. It is what provides the sun and the stars with the energy to shine continuously for billions of years. Nuclear fusion is when multiple atomic particles join together to create a larger atom. Fusion reactors join hydrogen atoms together to form helium atoms, neutrons and other forms of energy. This is the same type of nuclear energy used in hydrogen bombs. Fusion has been used here on earth to produce nuclear bombs, but has not yet been controlled so that we can obtain useful energy. Unlike nuclear fission, there is no limit on the amount of the fusion that can occur.
How it works :
Nuclear power stations work in pretty much the same way as fossil fuel-burning stations, except that a "chain reaction" inside a nuclear reactor makes the heat instead.
The reactor uses Uranium rods as fuel, and the heat is generated by nuclear fission: neutrons smash into the nucleus of the uranium atoms, which split roughly in half and release energy in the form of heat.
Carbon dioxide gas or water is pumped through the reactor to take the heat away, this then heats water to make steam.
The steam drives turbines which drive generators.
Modern nuclear power stations use the same type of turbines and generators as conventional power stations.
In Britain, nuclear power stations are often built on the coast, and use sea water for cooling the steam ready to be pumped round again. This means that they don't have the huge "cooling towers" seen at other power stations.
The reactor is controlled with "control rods", made of boron, which absorb neutrons. When the rods are lowered into the reactor, they absorb more neutrons and the fission process slows down. To generate more power, the rods are raised and more neutrons can crash into uranium atoms.
Advantages :
1- Nuclear power costs about the same as coal, so it's not expensive to make.
2- Does not produce smoke or carbon dioxide, so it does not contribute to the greenhouse effect.
3- Produces huge amounts of energy from small amounts of fuel.
4- Produces small amounts of waste.
5- Nuclear power is reliable.
Disadvantages :
1- Although not much waste is produced, it is very, very dangerous. It must be sealed up and buried for many thousands of years to allow the radioactivity to die away. For all that time it must be kept safe from earthquakes, flooding, terrorists and everything else. This is difficult.
2- Nuclear power is reliable, but a lot of money has to be spent on safety - if it does go wrong, a nuclear accident can be a major disaster. People are increasingly concerned about this - in the 1990's nuclear power was the fastest-growing source of power in much of the world. In 2005 it was the second slowest-growing.
Nuclear Power Station ( video )
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