But now to transform this energy transformation into actual steps it looks as the following: the chain reaction takes place, by first having neutrons penetrating into the nucleus of the uranium. The reason that this takes place is because the uranium nucleus has no charge, and therefore there is no repulsion of the neutrons taking place. After that, nuclear fission will occur after a thermal neutron penetrates the uranium nucleus. This will then cause the uranium nucleus to split into lighter nucleuses of different elements as well as giving of several neutrons. After that, these neutrons cause more fission in other nucleuses of the uranium and these new neutrons released start a chain reaction. Basically what happens is as follows:
U + N → X + Y +ZN
But however this is not all that takes place in a reaction, because moderates are required to control the rate of reactions as well as the critical mass needs to be taken in account. The critical mass is the minimum mass required for a chain reaction to take place. The moderator is normally used in a reaction with graphite, and it actually just looks like blocks of pure carbon arranged in a stack. But what they actually do, is reduce the speed of the neutrons released from fissions until they slow down, or become thermal neutrons, which can then produce fission by colliding with the uranium nucleuses.
Also another thing that controls the reaction, are control rods, and these rods are actual Boron-coated steel rods. And what they actually do, is control the rate at which neutrons are produced, by lowering and raising the rods away from the reactors. Another very crucial thing in this process is the heat exchangers. What the heat exchange does, is that it turns the hot gas released from the reaction into steam. By having cold-water flow through pipes on which the hot gas heats these pipes to from steam. And this goes and drives steam-powered turbines, which in the end produce electricity.
(Schematic0cross sectional drawing of a reactor)
However out of this whole trouble taken from these processes only 30%-35% of the potential energy stored is actually transformed to electricity. And if we sum up the advantages and disadvantages, we see the following:
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Fossil Fuels:
Fossil fuels are a type of power that has also caused a lot of controversy, because of the negative effects they have on the environment (e.g. global warming and green-house effect). Fossil fuel actually comes from the remains of Dead Sea animals that died millions of years ago. And actually what happened to them, is that their bones were crushed with each other and pressured by several of the earth piling on top of them until they finally formed fossil fuel but also the heat of the earths core, played a vital factor. The basic energy transformation that takes place in fossil fuel is that the potential energy stored, breaks down through to give heat energy, and that heat energy is transferred to kinetic energy, which drives a steam turbine that will generate electricity. The two very known fossil fuels are coal and oil.
However out of this energy transformation process, only 40-45% of the potential energy stored is actually transferred to electricity. And if sum up the advantages and disadvantages, we see the following:
After discussing the non-renewable sources, I am now going to talk about the renewable sources, and to be exact I am going to talk about the following 3 sources:
- Hydroelectric power:
The main energy transformation that takes place in hydroelectric power is that the kinetic energy of the waves, forces generators, which function like a pendulum, swing to vibrate and once they vibrate, they generate electric energy.
Out of this small process, the efficiency is only 35% out of the whole energy conversion. But this also however will depend on the wave velocity, because if it is greater, then more kinetic energy will be supplied, if we sum up the advantages and disadvantages, we see the following:
- Solar Power:
We can use the power of sun in 2 ways. The first way is by using the sunlight itself into making electrical energy; this is done by the help of photovoltaic cells. And basically what happens is that the sunlight hits the cells which convert these light signals into electrical signals. The second type is done by using the heat of the sun to heat the water which can be used to heat up houses directly or to drive steam turbines which will generate electricity.
Also one thing that must be taken into account, in this whole solar power issue. And that thing is the solar constant. The solar constant is the power collected at the top of the atmosphere by a unit area. But basically this can be summed up by saying that it describes the solar radiation, that falls on an area above the atmosphere at a certain angle. This “constant”, isn’t much of a constant because it actually varies on earth with the time of day and year, as well as with the latitude and weather. The maximum values vary between 0.8 and 1.0 KW/m2.
As for the efficiency of solar power, well it is disappointing to know that it is only 30% of the sun’s energy is actually transferred to electricity. And if we sum up the advantages and disadvantages, we see the following:
- Wind power:
A wind generator works by having the blades rotated by the wind, which causes a dynamo (which is like a generator) to spin and then electric energy is produced.
The power delivered by a wind generator, varies on the area with the rotor length being the diameter. This is given by the following formula:
P=Ek/t
And the efficiency of this wind generator is only 25% which is quiet poor really. And of we sum up the advantages and disadvantages, we see the following:
After summarising, both renewable and non-renewable sources, it is time for me to chose the best type of energy resources to use for our homes. The energy resources I suggest are more than 1. First of all the energy resources should be renewable, so that we don’t have to worry about the environment and peoples health (unlike fossil fuels and nuclear power). The second thing is that this renewable source, should not affect our environment or ecology (which means hydropower is dropped out!). Also the energy resource should be efficient, so that we can meet our basic demands for energy, (which means that wind energy also drops out!). After mentioning these three requirements (which seem essential in my own personal view), it is quiet obvious that the only energy source that I am talking about is Solar!. But however to improve this even more, would be if we insulate our homes well and do not waste our energy for no apparent reason(e.g. like leaving the lights of a room turned on, when no one is in the room. And also buying energy saving equipment). Because like I said at the beginning of this essay, without light we will become extinct. And we all know that we don’t want to become extinct, so lets do something about it and try and save our planet.
U= Uranium
N=Neutron
X+Y= Elements
Z= Number of