Have you ever heard of the word 'atom?' The atom is the basic unit of matter that forms everything in this universe. Everything you can think of – from galaxies to a glass of milk – is made up of atoms. While they can form colossal objects when clustered together, an individual atom is enormously small at best the diameter of an atom tends to vary from 1-1.5 nanometers. If you are not familiar to the idea of a nanometer, let's put it this way: approximately 5 million atoms can fit into a dot the size the period at the end of this sentence. That's how small an atom is.

Given that they form everything in the universe, we should obviously be thankful of their existence (none of us would be able to exist if atoms were never created – same goes for your glass of milk, the Earth, and so on). However, here's the most important part: we can generate enormous amounts of energy with these tiny atoms. In fact, that's what powers all those stars that lit the beautiful night sky. Welcome to Nuclear Energy.

The History of the Human Use of Nuclear Energy

Nuclear energy is produced from a physical reaction called a Fission Reaction. This was discovered in 1938 by two German physicists, Otto Hahn and Fritz Straussmann. By 1938 it was widely known in academic society (we're talking history here, so if you want to know the scientific side of fission, go to the next section).

Ironically, the nation that benefited the most from this discovery was not Germany (where the discovery was made), but the USA. The Nazi Regime that came to power in Germany a few years earlier began purging the German population of all Jews – the result of this was that the majority of Germany's top physicists (who happened to be largely Jewish) fled the nation, typically into Britain and USA. While the UK hardly had attention to spare because of the ensuing WWII in Europe, the USA, thousands of kilometres away and therefore not directly concerned with the war, welcomed the flow of 'valuable brains' into their country. Under actively support of the US government, the German physicists in cooperation with American physicists discovered that an accelerated nuclear fission of a highly unstable element could release enormous amounts of energy at a very fast rate. They eventually used this principle to make the atomic bomb –namely, a mechanism that could trigger the nuclear fission of a heavy element and cause destruction with the energy released in form of heat and shockwave.

The first a-bomb was dropped in Hiroshima, on the 6th of August, 1945. Another was dropped in Nagasaki, three days later. The sudden nuclear chain reaction evaporated or carbonized every form of life within kilometers of the explosion spot. Seconds after explosion, an immense shockwave passed throughout the city at the speed of sound, causing destruction and havoc. Hundreds of thousands of lives were lost in the two bombings.

Fortunately, since then, nuclear fission has been used in more peaceful and positive aspects. Nuclear Fission is used for medical treatments, as in part of X-rays. But the biggest use of nuclear fission is in producing energy.

How does Nuclear Fission Produce Electricity?

What if I told you can get energy from splitting things in two? You might wonder, 'Well, that's strange. I've broken thousands of dishes and there wasn't a bit of energy produced.' Of course, it doesn't work that way (well, in a way it does - your mom is producing energy when she yells at you).

When I say 'You can get energy from breaking things apart,' I mean breaking things in a smaller scale, not something as big as dishes. If you think for a moment, most conventional sources of energy are acquired from breaking things apart. When you are burning something, or combusting something, you are using heat to break or make chemical bonds, and energy is produced in the process. Usually the energy is in the form of heat, but can take other forms, such as sound and light. These reactions – breaking bonds between atoms or molecules – are called chemical reactions.

Nuclear fission is quite similar to chemical reactions, but has a very important difference. As mentioned before, when we generate nuclear energy, we use a physical concept called 'fission.' Fission is when an unstable element (or atoms) breaks into many different and smaller atoms over and over again. The energy stored in the bonds between the subatomic particles is released. Rather than breaking connections of atoms and atoms by force, which cause combustion, nuclear energy is acquired by breaking apart the atoms themselves.

Of course, it is not very easy to break an atom apart. Though, practically, all atoms are hard to break, some atoms are easier to break then others. Generally, the heavier the element, the unstable and easier it is to break the atom up. That is why we generally use Uranium for generation nuclear energy, the heaviest naturally-existing element. Uranium is a mineral, and we need to mine it from the ground. Once the Uranium ore is mined, it is purified in order to extract a particular type of Uranium – this is called Uranium-235, and is what will ultimately end up in those power plants.

But, even if we do use Uranium, it still takes some energy to break the atom apart. We need to shoot a particle into the nucleus very fast enough to penetrate the nucleus. That particle is the neutron. The neutron is big enough to do some effect on the nucleus, and has a habit of making the nucleus badly unstable when plunged into the nucleus by force.

I will now try to explain nuclear fission as briefly as possible. Let's imagine you've finally secured a Uranium atom in your garage. You wanna start a fission reaction? Well, firstly, fire a single neutron into the nucleus of a Uranium-235 atom at the speed 90 % of the speed of light. That's jolly fast, but it can't be any slower - if the neutron was any slower, the strong force of the nucleus would deflect the neutron, and shoot it back right out, just as a tennis racket deflects a tennis ball. However, at a speed 90 % of the speed of light, the neutron is fast enough to defy the strong force of the nucleus and plunge into it. It actually becomes a part of the Uranium atom, and we?ve ended up with having one more neutron than what there is supposed to be. This changes the Uranium-235 into Uranium-236, which is terribly unstable - the atom is forced to split into two smaller and stable atoms called Barium-142 and Krypton-91 respectively. Also, three neutrons shoot out as a by-product of the reaction. Now here's the important bit - the bonds originally holding the Uranium atom together is converted into energy, and this energy is released in form of heat, light, and shockwave.

Just a minute – we're not done yet. Let's suppose there was not just one Uranium atom, but a dozen of Uranium atoms (or gazillions, it doesn't matter as long as there's more than one). The three neutrons we got from the first Uranium atom shoot out into infinity and beyond. Mind you – they're extremely fast. And if they happen to strike another Uranium atom hanging around, that speed is fast enough to cause fission reaction within that atom. And the neutrons produced strikes other Uranium atoms, and cause fission reaction within those atoms, and the neutrons produced strikes other Uranium atoms, and cause fission reaction within those atoms, and the neutrons produced strikes other Uranium atoms, and – whatever. This is called a chain reaction, and goes on until all the Uranium atoms have been used up. A single reaction does not give off tons of energy, but because there are gazillions more Uranium atoms, there are millions of reactions taking place, and a huge amount of energy is produced in the process. This is pretty much what happens in an actual nuclear fission chamber in a nuclear power plant (and what could have happened in your garage if you took me seriously).

As usual, it breaks down to how to convert this energy into electricity. For that, power plants use a relatively simple mechanism. Firstly, the heat is used to boil water into steam (we don't really get to use the sound and light energy, but that loss isn't significant). This steam travels through a narrow chamber and turns a turbine. The rest of the story is pretty self-explanatory – the rotation turns the generator, which produces electricity.

If you happen to visit a nuclear power plant or watch a documentary portraying it, you will see several enormous, white towers looming over everything. Those towers (what usually characterize a nuclear power plant) are cooling towers, condensing the steam back into water, so that it can be recycled over and over again.

Advantages & Disadvantages

Nuclear energy is good news to politicians and directors worried about energy outputs. The fission reaction of 1 g of Uranium-235 yields around 1 MW of useful energy, which is equivalent to the energy acquired from burning 3 tons of coal, or 600 gallons of petroleum. This is an enormous output for a very small amount of fuel, and makes nuclear energy the energy source with the highest output in the world. Also, the fission reaction of Uranium does not emit CO2 as the combustion of fossil fuels do.

Now for the bad news. In order to generate electricity from nuclear power plants we need Uranium, which is a mineral and thus is unrenewable. Though it is impossible to speculate how much Uranium we have left on Earth, it is becoming increasingly difficult to find untouched Uranium veins. Ultimately we will run out of Uranium supplies, and then we would have to find something able to replace Uranium.

Then there are the by-products of nuclear fission. We already mentioned that the nuclear fission of Uranium atoms produces Barium-142 atoms and Krypton-91 atoms. These elements are relatively stable, but will break down over a period of time, releasing heat and radioactivity (this phenomenon is called radioactive decay). This radiation is destructive to cells, particularly to the nucleus, and causes cells to mutate, leading to cancer. Thus, the radioactive remains of nuclear fission – along with any sort of clothing or tools that have come in contact with those remains – must be processed and stored away so that it may not harm anyone. The method typically used is to seal the radioactive waste in lead barrels and stowing them away in depots located within mountains. That at least ensures that the radioactive waste will not be dangerous to anyone, but it takes a considerable amount of money and space to run this process.

Lastly, there is always the risk of power plant accidents, which can have lethal effects on the entire globe, regardless of where it happened. In other power plants, an accident simply means the closing down of the facilities and waiting for maintenance. In nuclear power plants, however, an accident often means the leakage of radioactivity into the atmosphere, which can have catastrophic results.

For example, the explosion of the Chernobyl Nuclear Power Plant on April 26^th, 1986, saw highly radioactive smoke pouring out and contaminating the entire Europe. People felt they were surrounded by an enemy they couldn't even see- just like a disease. People couldn't go out, nor eat dairy products or vegetables safely, in fear that they were polluted by radiation. The Chernobyl Disaster was caused because of poor control on the Nuclear reactors, but accidents can happen even under the most careful management. The Fukushima Nuclear Reactor Incident of 2012 was not caused by human hands, but by a natural disaster- earthquake (or rather the resulting tsunami). An earthquake with Richter scale of 6 can easily leak a Nuclear Reactor. And considering that earthquakes can happen virtually anywhere on Earth, Nuclear Power Plants really are a high risk.

Cast Study

In order for a country to be able to produce nuclear energy, two conditions must be attained: a) a sufficient and regularly-replenished supply of Uranium, and b) adequate technology and trained personnel to manage and run the power plants. Some countries, such as USA and France, have both the technology and the mineral, satisfy both demands some countries, such as South Korea, have no Uranium, and have it imported from foreign nations. Lastly, some nations, such as Australia, produce Uranium, but do not use nuclear power.

Currently, more than 400 nuclear power plants operate around the world in 32 countries, generating in total approximately one-sixth of the world?s electricity supply. France generates 76% of her electricity from nuclear power plants Belgium, 56% South Korea, 36% Switzerland, 40% Sweden, 47%? Finland, 30% Japan, 33% the United Kingdom, 25% Bulgaria, 46% Hungary, 42% (source: http://www2.lbl.gov/abc/wallchart/chapters/14/1.html). USA relies on nuclear energy for 20 % of her electricity demands although this is far from being first place percentage-wise, USA boast the most nuclear power plants in the world (more than 100 operating), and the most nuclear power plant electricity generated (98,000 MWe). 

Nuclear energy is also used by the navy to power naval vessels that must operate for a long period without docking. When compared to running on fossil fuel engines, nuclear engines give the vessel a greater thrust for a greater period of time. The majority of the USA's attack submarine vessels and aircraft carriers rely on nuclear power Russia and the United Kingdom have also built nuclear submarines. Recently, nuclear power has seen limited usage on non-military vessels as well, such as ice-breaker ships and trade vessels.

Areas of Research in the Future

With the current nuclear power technology, safety is notably the most conspicuous flaw. Nuclear power plants would have to become much less riskier, and a better method of disposing the radioactive waste would have to be devised. Scientists are currently drawing a plan of loading a rocket with nuclear waste and shooting it into space, effectively getting rid of it however, there is always the danger of the rocket exploding mid-air, in which case the radioactive waste would literally 'rain down' on Earth with catastrophic results.

Apart from that, scientists are currently researching another form of nuclear power – nuclear fusion. Both fission and fusion temporarily break the bonds within atoms to release energy, but the two have a very important difference. We might say that fusion is quite the opposite of fission for while fission is dividing an atom into two atoms, fusion is taking two atoms and smooshing it into one atom.

Unlike Fission, nuclear fusion does not produce any radioactive chemicals. While nuclear fission requires Uranium or other heavy elements (which are quite rare), nuclear fusion typically needs various types of Hydrogen, which can be found easily in the atmosphere. Besides, while Uranium is a mineral that is unrenewable, Hydrogen can be produced by simple chemical reactions, and can be deemed as renewable. Furthermore, the by-product of nuclear fusion is Helium, which is not radioactive, and thus needs no processing or disposing whatsoever (in fact, it can be just released into the atmosphere, or even be used to blow up your birthday balloon).

The current disadvantage of fusion energy is the tremendous amount of heat produced in the reaction. There is no material on the Earth that can withstand this immense heat, and therefore we still have no feasible container for fusion reactions that can be used in power plants. However, recently, it has been discovered that a sufficiently strong electromagnetic force field may be able contain the fusion reaction. There are yet no operating fusion power plants yet, but they will certainly be used in the future.

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