Thursday 13 October 2011

What is Nuclear Energy

The greatest problem facing mankind in the 21st century is that of shortage of energy. As we consume our fossil fuel reserves rapidly, the search for alternative sources of energy which can be effective substitutes is underway. The most powerful alternative today is nuclear energy which is derived from certain radioactive elements like Uranium. The aim of this article is to explain what is nuclear energy and how it is harnessed to provide electrical power to entire cities.

What is Nuclear Energy and How Does it Work?

To understand what is nuclear energy made of, you need to understand the process of nuclear fission. Nuclear energy has a long history and it all began with the discovery of radioactivity at the end of the 19th century. Certain chemical elements like Uranium, Plutonium, Radium and Polonium were discovered to be emitting certain ionizing radiations, which were later classified to be Alpha rays (Helium nuclei), Beta rays (high speed electrons) and Gamma rays (high energy electromagnetic waves). For more, check out the time line and history of nuclear energy.

It was understood that these radioactive nuclei were unstable and therefore emitted ionizing radiation to get transformed into more stable nuclei. This process of transformation of radioactive elements was known to be radioactive decay. When physicists bombarded certain radioactive elements with neutrons (neutral subatomic particles), they discovered the new phenomenon of 'nuclear fission', which was harnessed to create nuclear energy as an alternative source of power. One of the nuclear energy facts to note is that nuclear fission was discovered by Otto Hahn and Fritz Strassmann in 1938 in Berlin, Germany. Check out the nuclear energy - pros and cons.

When a neutron is bombarded at a fissionable radioactive nucleus like Uranium-235, it's absorbed and a new unstable element is created, which subsequently disintegrates into two stable nuclei, along with the release of tremendous energy. This is nuclear fission.

The mass of the non-disintegrated nucleus is greater than the mass of the two split nuclei put together. The difference in mass is converted into energy. The magnitude of this energy can be estimated by the law - E = mc2, where m is the difference in mass and c is the speed of light (3 x 108 meters per second).

Thus nuclear fission unlocks the energy stored in the atomic nucleus and unleashes it for the use of mankind. So how does nuclear power work? It works through the setting up of nuclear reactors. The energy derived from the nuclear reactor is derived through millions of such fission events that occur within a stack of Uranium-235, which is bombarded by neutrons in a nuclear reactor core.

Nuclear fission within the stack of enriched Uranium-235 is sustained by a chain reaction. Every fission of Uranium nuclei also emits neutrons along with energy, which strike other nuclei to trigger more fission reactions. This chain of fission cascading chain reactions releases a tremendous amount of energy.

So how does a nuclear power plant work, to harness this energy? In the reactor, water is circulated around the Uranium core which gets heated due to the emission of released nuclear energy. This heat transforms the water into steam which is passed through thin tubes to be sprayed on turbines, which are connected to generators. The mechanical energy of the turbines is subsequently transformed into electrical energy by the generator and transmitted to our electrical grid. So if you are curious about what is nuclear energy used for, know that it's used to provide electrical power.

Now that you know what is nuclear energy, I suggest that you study the phenomenon in more detail by studying nuclear physics. As discussed before, nuclear energy created in nuclear reactors is made possible due to controlled fission of certain radioactive elements like Uranium-235. On the other hand, an atomic bomb is an example of uncontrolled fission. It's a great example of how destructive uncontrolled power can be and the same power can be constructive when it's harnessed in the right way!

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