The advantages and disadvantages of nuclear power and fossil fuels and which is the better source of energy for the near future? Is it a long-term solution? Is there a better solution currently under development?
The advantages and disadvantages of nuclear power and fossil fuels and which is the better source of energy for the near future? Is it a long-term solution? Is there a better solution currently under development?
This report aims to discuss the advantages and disadvantages of the two main methods of electricity production, and to decide on which method seems to be the best for large scale electricity production in the future, based on each method's economical and environmental implications.
The most widely used fuel in power plants is coal.1 Research into alternative fuel sources stems from concerns about the global environment The problem about choosing whether or not to completely 'go nuclear' or carry on using fossil fuels stems from many environmental and economic factors. The ideal power source will produce the largest amount of energy achievable at an affordable cost, with as little environmental pollution as possible. In this report, I will discuss the advantages and disadvantages of fossil fuels and nuclear power, and which comes the closest to fitting this 'ideal' power source model. From this I will speculate on the best way forward for large-scale energy production. When I have drawn conclusions concerning these two methods of energy production, I will then discuss the energy production ideas that are currently being researched and developed by physicists, and whether or not these ideas are better than current ideas and potentially the energy resource that fits the 'ideal' model perfectly.
Background information
Most power plants around the world are steam-electric plants. This means that the energy created is produced by great deals of steam turning the blades of a giant turbine, which spins the shaft of a huge generator. Inside the generator, coils of wire and magnetic fields interact, and electricity is created.1
All steam-electric power plants produce electricity in just this way. What changes is whether using coal, natural gas, oil or nuclear energy to heat the water to produce the steam.
In a fossil-fuelled plant, you burn coal, natural gas or oil to heat water in a boiler, turning it into steam to turn the turbine. Of these three, coal is the most widely used.
In a nuclear plant, you don't burn anything at all. Instead, you split atoms of uranium, which creates the heat that turns the water into steam. Splitting atoms is called fission.
There are other kinds of power plant used around the world but they are generally considered inappropriate for large-scale power production. Despite them being 'environmentally friendly,' their cost often out-weights their energy return. A short table summarising the reasons why this is the case is displayed below.2
Whatever the fuel, the method used to generate electricity is almost identical all over the world.
How an electricity generator works
Both nuclear and fossil fuel power plants use generators driven by turbines to produce their electricity.
The generator is based on the principle of "electromagnetic induction" discovered in 1831 by Michael Faraday, a British scientist. Faraday discovered that if an electric conductor, like a copper wire, is moved through a magnetic field, electric current will flow (be induced) in the conductor. So the mechanical energy of the moving wire is converted into the electric energy of the current that flows in the wire. 4
Faraday's law states5:
E = N x ??/?t volts
Where E is energy, N is the number of turns, ? is magnetic flux and t is time. This means that is the number of turns in the coil is increased, so is the energy produced. The generators used in power stations involve huge coils with many turns moving in strong magnetic fields. These coils are rotated in the magnetic field by massive turbines. These turbines are driven by steam. The difference in fossil fuel plants and nuclear plants is simply how the steam is produced.
Both kinds of plant also use transformers to increase the voltage of the electricity produced before it is fed onto the national grid (the national electricity distribution system) and to reduce the voltage before the electricity reaches the consumer. This is to reduce the cost of electricity for both consumer and producer.
Consider the following:
• Electricity is generated at the generating plant at 240 Volts and then
delivered to the households over conductors.
• There are 10 households and each needs, for example, 1000 Watts.
• The electric company must therefore supply 10x1000 = 10,000 Watts.
• Current - Power / Voltage (I = P/V)
• So Current = 10,000/240 = 41.7 amps
• But, electrical power is dissipated as heat according to P = I2R (this is how
electrical stoves work)
• Lets assume R (resistance) =1: We now have:
Heat dissipation = (41.7)*(41.7)(1) - 1739 watts.
• Heat dissipation is energy lost by the system. This loss is unavoidable!
• To deliver the 10,000 watts that the consumer needs requires that we
generate 1739 watts and hence have an overall efficiency of
(10,000/11,739) x 100-85%. Which is a 15% loss the consumer would pay for! (This is far worse in the US which generates electricity at 120 volts, and has an efficiency of around 59%)
You can solve this loss problem using a transformer to change the voltage.6
Current = Power/Voltage; If we increase V by a factor of 10, then I lowers by a factor of 10 (at constant power) and the power dissipated as heat lowers by a factor of 102. Hence at 1200 Volts we have only 69.4 watts of energy loss and a 99% energy efficient delivery system, which is much cheaper for both producer and buyer.
How a transformer works
(A transformer)
A transformer uses alternating current in one coil to induce alternating current in another. The induced voltage is given by: Vout = Vin x N2/N1 where N1= Number of coils in the Primary and N2= Number of coils in the secondary. When N2 is less than N1, we reduce Vout. This is why there are transformers on power lines to step the voltage down to 240 Volts by the time it reaches your house. 7
How does each power plant work?
Fossil fuels
(See Diagram 1 on separate sheet) 11
This is an example of how a fossil fuel power station works, using coal as the fuel. Most fossil fuel plants work in this way, regardless of the fuel being coal, gas or oil.
. Coal Supply
Coal from the mine is delivered to the coal hopper, where it is crushed to five centimetres (2 inches) in size. The coal is processed and delivered by a conveyor belt to the generating plant.
2. Boiler
. The coal / air mixture ignites instantly in the boiler.
2. Millions of litres of purified water are pumped through tubes inside the
boiler.
3. Intense heat from the burning coal turns the purified water in the boiler.
3. Stack
Burning coal produces carbon dioxide (CO2), sulphur dioxide (SO2) and nitrogen oxides (NOx).
These gases are vented from the boiler.
Bottom ash, which is made of coarse fragments that fall to the bottom of the boiler, is removed. Fly ash, which is very light, exits the boiler along with the hot gases. An electrostatic precipitator (a huge air filter) removes 99.4 per cent of fly ash before the flue gases are dispersed into the atmosphere.
4. Turbine
. Water in the boiler tubes picks up heat from the boiler and turns into
steam.
2. The high-pressure steam from the boiler passes into the turbine (a
massive drum with thousands of propeller blades).
3. Once the steam hits the turbine blades, it causes the turbine to spin
rapidly.
4. The spinning turbine causes a shaft to turn inside the generator, creating
an electric current.
5. Condensers and the cooling water system
. Cooling water is drawn into the plant and circulated through condensers,
which cools steam discharged from the turbine.
2. Steam from the turbine also passes through the condensers in separate
pipes from cooling water.
3. The cold water is warmed by the steam, which condenses back into pure
water and circulates back to the boiler to begin the process of generating
electricity again.
4. Cooling water, now warm from the heat exchange in the condensers, is
released from the plant.
6. Substation, transformer, transmission lines
. Once the electricity is generated, transformers increase the voltage so it
can be carried across the transmission lines.
2. Once electricity is delivered to substations in cities and towns, the voltage
flowing into the distribution lines is reduced, and then reduced again to
distribute electricity to customers.
Nuclear Power station
...
This is a preview of the whole essay
water and circulates back to the boiler to begin the process of generating
electricity again.
4. Cooling water, now warm from the heat exchange in the condensers, is
released from the plant.
6. Substation, transformer, transmission lines
. Once the electricity is generated, transformers increase the voltage so it
can be carried across the transmission lines.
2. Once electricity is delivered to substations in cities and towns, the voltage
flowing into the distribution lines is reduced, and then reduced again to
distribute electricity to customers.
Nuclear Power station
(See Diagram 2 on separate sheet) 12
You can see from the diagram that the nuclear power plant works on the same fundamental principles as the fossil fuel plant. They both turn huge blades connected to a generator using steam. However, the way in which the steam is produced is very different from the process used in fossil fuel plants. Instead of burning anything, atoms of Uranium are split to produce large amounts of energy to heat water.
Nuclear reactors are basically machines that contain and control chain reactions, while releasing heat at a controlled rate. In nuclear power plants, the reactors supply the heat to turn water into steam, which drives the turbine-generators.
The reactor core (1) is composed of four main elements:
FUEL. Nuclear fuel consists of pellets of enriched uranium dioxide encased in 12-foot long pencil-thick metal tubes, called fuel rods. These fuel rods are bundled to form fuel assemblies. A nuclear plant can operate continuously for up to 2 years. To run this long, a reactor must have as many as 100 to 300 fuel assemblies.
CONTROL RODS. The control rods contain material that regulates the rate of the chain reaction. If they are pulled out of the core, the reaction speeds up. If they are inserted, the reaction slows down.
THE COOLANT. A coolant, usually water, is pumped through the reactor to carry away the heat produced by the fission of the Uranium. This is comparable to the water in the cooling system of a car, which carries away the heat built up in the engine. In a reactor, as much as 330,000 gallons of water flow through the reactor core every minute to carry away the heat.
THE MODERATOR. A moderator, water, slows down the speed at which atoms travel. This reduction in speed actually increases the opportunity to split, thereby releasing energy
Engineers have developed different types of nuclear power plants. Two types are used in the United States: boiling-water reactors (BWRs), and pressurized-water reactors (PWRs).
In the BWR, the water heated by the reactor core turns directly into steam in the reactor vessel and is then used to power the turbine-generator. In a PWR, the water passing through the reactor core is kept under pressure so that it does not turn to steam at all - it remains liquid. Steam to drive the turbine is generated in a separate piece of equipment called a steam generator. A steam generator is a giant cylinder with thousands of tubes in it through which the hot radioactive water can flow. Outside the tubes in the steam generator, non-radioactive water (or clean water) boils and eventually turns to steam. The clean water may come from one of several sources: oceans, lakes or rivers. The radioactive water flows back to the reactor core, where it is reheated, only to flow back to the steam generator. Roughly seventy percent of the reactors operating in the U.S. are PWR.
How much energy is produced?
In nuclear energy an incredible amount of energy is released, in the form of heat and gamma radiation, when a single atom splits. The two atoms that result from the fission later release beta radiation and gamma radiation of their own as well. The energy released by a single fission comes from the fact that the fission products and the neutrons, together, weigh less than the original U-235 atom.
This difference in mass, Am is known as the MASS DEFECT3 or MASS DEFICIT
The mass defect for a nucleus is given by:
Where:
M = Experimental mass of nucleus
mp = Mass of proton
mn = Mass of neutron
Z = Charge number
n = Number of neutrons
A = Mass number
E = ?m x c2 indicates that the mass defect ?m which is lost in the formation of stable nucleus and is converted into energy. This amount of energy must be released when nucleons are combined to form a stable nucleus. This is the binding energy that holds the nucleons in a nucleus so that despite strong repulsive forces between protons they are forced to unite in the nucleus.
Something on the order of 200 MeV (million electron volts) is released by the decay of one U-235 atom (1 eV is equal to 1 .602 x 10 '2 ergs. 1 x 107 ergs is equal to 1 joule. 1 joule equals 1 watt-second.) That may not seem like much, but there are a lot of uranium atoms in a pound of uranium. 14
The fission of stable Uranium-235 caused by collision with a slow neutron is shown in the diagram. A strong nuclear force must be present inside the nucleus to overcome the repulsion between protons. The neutrons assist in providing this force. Adding an extra neutron alters these forces and makes the nucleus unstable.
When a neutron penetrates the nucleus of a U235 atom, it becomes U236. This is unstable and nuclear fission occurs, producing a pair of fission nuclei. One pair of fission products is Barium-144 and Krypton-89, accompanied by three fast moving neutrons. This is represented by:
92U235 + 0n1 --> 56Ba144 + 36Kr89 + 3on1 ˜ 200MeV
If a neutron ejected during fission can be used to cause fission in another U235 nucleus, then a chain reaction is set up.
The products formed in the fission process can vary just by chance, e.g. Strontiurn-90 and xenon-143 can also be formed. 13
A comparison between fossil fuels and nuclear fuel can be summed up in one phrase from an Information poster supplied by my teacher.
"Around 40 million Uranium atoms undergo fission to release about 1 joule of energy. It is estimated that the nuclear reactions in 1 tonne of uranium will eventually transfer as much energy to the electrical supply system as the chemical reaction of burning 20 000 tonne of coal."
- Information poster supplied by my teacher
From this it is quite clear that the fission of Uranium is a far more efficient energy source than fossil fuels.
Environmental implications
Fossil Fuels
Fossil fuels have been linked with various problems. These include human health problems caused by air pollution from the burning of coal and oil; damage to land from coal mining and to miners from black lung disease; environmental degradation caused by global warming, acid rain, and water pollution; and national security costs, such as protecting foreign sources of oil. 11
Among the gases emitted when fossil fuels are burned, one of the most significant is carbon dioxide, a gas that traps heat in the earth's atmosphere. Over the last 150 years, burning fossil fuels has resulted in more than a 25 percent increase in the amount of carbon dioxide in our atmosphere. Fossil fuels are also implicated in increased levels of atmospheric methane and nitrous oxide, although they are not the major source of these gases.
The increase in levels of Carbon Dioxide in the atmosphere has been attributed to "The greenhouse effect." which causes an increase in the planet's temperature. The greenhouse effect because heat from the sun reflected by Earth is absorbed by a Carbon Dioxide molecule. This heat is then reradiated back to the Earth.
Climate scientists predict that if carbon dioxide levels continue to increase, the planet will become warmer in the next century. Projected temperature increases will most likely result in a variety of impacts. In coastal areas, sea-level rise due to the warming of the oceans and the melting of glaciers may lead to the inundation of wetlands, river deltas, and even populated areas. Altered weather patterns may result in more extreme weather events. And inland agricultural zones could suffer an increase in the frequency of droughts.
Fossil fuels are also linked to the decrease of air quality. Clean air is essential to life and good health. Several important pollutants are produced by fossil fuel combustion: carbon monoxide, nitrogen oxides, sulphur oxides, and hydrocarbons. In addition, total suspended particulates contribute to air pollution, and nitrogen oxides and hydrocarbons can combine in the atmosphere to form tropospheric ozone, the major constituent of smog.
Carbon monoxide is a gas formed as a by-product during the incomplete combustion of all fossil fuels. Exposure to carbon monoxide can cause headaches and place additional stress on people with heart disease.
Two oxides of nitrogen-nitrogen dioxide and nitric oxide-are formed in combustion. Nitrogen oxides appear as yellowish-brown clouds over many city skylines. They can irritate the lungs, cause bronchitis and pneumonia, and decrease resistance to respiratory infections. They also lead to the formation of smog. Power plants are responsible for close to half of the US emissions of nitrogen oxides.
Sulphur oxides are produced by the oxidization of the available sculpture in a fuel. Utilities that use coal to generate electricity produce two-thirds of the nation's sulphur dioxide emissions. Nitrogen oxides and sulphur oxides are important constituents of acid rain. These gases combine with water vapour in clouds to form sulphuric and nitric acids, which become part of rain and snow. As the acids accumulate, lakes and rivers become too acidic for plant and animal life. Acid rain also affects crops and buildings.
The white haze that can be seen over many cities is tropospheric ozone, or smog. This gas is not emitted directly into the air; rather, it is formed when ozone precursors mainly non-methane hydrocarbons and nitrogen oxides react in the presence of heat and sunlight. Human exposure to ozone can produce shortness of breath and, over time, permanent lung damage. Research shows that ozone may be harmful at levels even lower than the current federal air standard. In addition, it can reduce crop yields.
Finally, fossil fuel use also produces particulates, including dust, soot, smoke, and other suspended matter, which are respiratory irritants. In addition, particulates may contribute to acid rain formation.
There is also the problem of thermal pollution. During the electricity-generation process, burning fossil fuels produce heat energy, some of which is used to generate electricity. Because the process is inefficient, much of the heat is released to the atmosphere or to water that is used as a coolant. Heated air is not a problem, but heated water, once returned to rivers or lakes, can upset the aquatic ecosystem.
Nuclear Power
While nuclear power does not pollute the air anything like fossil fuels, there are still many environmental concerns. The main fear appears to be that radiation can cause cancer. While this is true, the general public do not seem to understand they are exposed to radiation all the time. There is a natural level of radiation known as "'background radiation" which comes from everywhere. Radioactive substances are often left to decay until their activity matches this background level of radiation. At this point, they become safe to handle.
This graph shows the decrease in radioactivity for Carbon-14 over time. Every radioactive material follows an exponential curve very much like this. The blue line indicates background radiation levels.
Radioactive decays follow a simple pattern. You cannot predict which nucleus will decay next, or when a particular nucleus will decay, but if you have a large sample of nuclei of the same type, then a certain proportion of them will decay every second, on the average. This proportion is called the decay constant and is usually symbolized with the Greek letter lambda. Substances with a small decay constant send out relatively little radiation: substances with a large decay constant send out more (per unit mass of substance) and are thus more radioactive.
If we measure the number of decays n in a sample of a substance with N atoms (and nuclei) in it for a period of time Dt, the decay constant Lambda will be approximately
? = n/ (NDt)
The bigger the sample, the closer you'll get to finding the "real" decay rate, but in any finite sized sample there is always some statistical fluctuation. However, you can generally measure lambda quite accurately because there are a great many atoms in any macroscopic piece of matter. 9
Each radioactive substance has its own "half life." This is the amount of time it takes for half the number of atoms in a substance to decay.
As radioactive elements decay, they change into other elements. Decay continues until a nonradioactive nucleus is formed. This process is called the decay series. There are 3 types of radioactive decay
• Alpha decay: The nucleus releases an alpha particle. This decreases the mass number by 4 and the atomic number by 2. Uraniurn-238 undergoes alpha decay.
• Beta decay: The nucleus releases a beta particle. This does not decrease the
mass number, but does decrease the atomic number by one. Carbon-14
undergoes beta decay.
• Gamma decay: The nucleus releases a gamma ray. Gamma decay almost
always accompanies alpha and beta decay. The nucleus does not change. It makes a transition to a lower energy state.
The radioactivity of a substance is measured by the number of decays that occur during a given period of time. Here are 2 common units of measurement for radioactivity. 10
• The curie (Ci)
Ci = 3.7 x 10:c decays/s
• The Becquerel (Bq), an SI unit 1 Bq = 1 decay/s
These units do not accurately measure how dangerous a given amount of radiation might be for humans. For medical purposes, other units of measurement reflecting this aspect are more appropriate.
Most substances reach safe radiation levels after around 10 to 20 half lives. The "half life" of a substance is the time take for half of the nuclei in a sample to decay to a stable form.
The problem is unfortunately how to store all the nuclear waste. Generally 10-20 half lives is called the hazardous life of the waste. Example: Plutonium-239 which is in irradiated fuel, has a half-life of 24,400 years. It is dangerous for a quarter million years, or 12,000 human generations. As it decays, uranium-235 is generated, with a half-life 710,000 years. Thus the hazard of irradiated fuel will continue for millions of years. This material must be isolated from contaminating or irradiating living things for this long. 9
There are many fears from the general public about nuclear power, especially after the well-documented accidents in three-mile island and Chernobyl. The fear seems to be that an accident could cause wide spread destruction and many deaths.
Anyone against the use of nuclear power will cite the Chernobyl disaster as one of their main reasons. Several things caused the disaster at Chernobyl. The plant was not properly designed, and could only be run with very specific instructions. The operators of the plant failed to properly follow these instructions, and some scientists conducted a highly risky experiment that led to the explosion. To conduct the experiment, and had to remove safety and cooling equipment in order to do so. Eventually, pressure on the reactor's roof blew it away. Everything inside, including molten uranium, burning graphite, and radioactive ashes were emitted into the atmosphere. This was not a nuclear explosion. There was no chain reaction or explosion like that in an atomic bomb.11 However, the amount of radioactive material released was ten times that caused by the US atomic bombing of Hiroshima. Radioactive fallout spread throughout Europe. It hit Poland, Germany, Belgium, France, and Holland, and then shifted towards the Balkans and Italy. There has even been a government report published in "New scientist" magazine which states:
"Fallout from the accident at Chernobyl nuclear power station in the Ukraine may have led to hundreds of deaths and deformities among babies in Britain.
It is impossible to tell just how many people the Chernobyl explosion affected. A British report estimated that the radioactivity will give 2300 people cancer, though others think the number is much higher. 16
This is the kind of worst-case scenario that worries a lot of people. However the statistics tell a different story.
While no source of electrical power generation is completely safe, nuclear power has a remarkable record. About 20% of electricity generated in the U.S. comes from nuclear power, and in the last forty years of this production, not one single fatality has occurred as a result of the operation of a civilian nuclear power plant in the United States, Western Europe, Japan, or South Korea. No other form of energy production can even come close. 17
Like all industrial processes, nuclear power generation has by-product wastes: radioactive waste and hot water. Because nuclear generated electricity does not emit carbon dioxide into the atmosphere, nuclear power plants in the U.S. prevent about as much greenhouse has emissions as taking 5 billion cars off our streets and highways.
Radioactive wastes are the principal environmental concern for nuclear power. Most nuclear waste is low-level nuclear waste. It is ordinary trash, tools, protective clothing, wiping cloths and disposable items that have been contaminated with small amounts of radioactive dust or particles. These materials are subject to special regulations that govern their storage so they will not come in contact with the outside environment.
On the other hand the irradiated fuel assemblies are highly radioactive and must be stored in specially designed pools resembling large swimming pools (water cools the fuel and acts as a radiation shield) or in specially designed dry storage containers. This is to let the radioactive waste decay to a safer level, before being stored elsewhere. The older and less radioactive fuel is kept in the dry storage facility. It is sealed in special concrete reinforced containers. The United States Department of Energy's long-range plan is for this spent fuel to be stored deep in the earth in a geologic repository. The proposed site is Yucca Mountain, Nevada. Currently, all spent (used) fuel is stored at the power plant at which it was used.
Another problem with nuclear power was first encountered after the Chernobyl disaster. The surrounding area of the plant was deemed uninhabitable due to the radiation levels after the accident. It was only again deemed habitable after Russian scientists decided the radioactive material with the longest half-life present in the area after the accident had decayed to background radiation levels.
Comparison
A report from "howstuffworks.com" says:
"(Burning fossil fuels) also produces smaller amounts of just about every element on the periodic table, including the radioactive ones. In fact, a coal-burning power plant emits more radiation than a (properly functioning) nuclear power plant."
The use of fossil fuels causes millions of tonnes of toxic and greenhouse gases into the atmosphere. Whilst nuclear power dose not, the problems with dealing with waste products and potential disasters releasing radioactive gas into the atmosphere can not be ignored and still raises just as much concern.
Economic implications
Fossil Fuels
Fossil fuel mining is relatively cheap and easy. However, the UK has had to close many coalmines due to safety fears. Many have become unstable and caved in. Oil supplies in the North Sea are also running low. New sources of energy are going to be needed soon.
The UK and USA's fossil fuel dependence means that, to ensure our supply, they may be forced to protect foreign sources of oil. The Persian Gulf War is a perfect example: US troops were sent to the Gulf in part to guard against a possible cut off of our oil supply. Although the war is over, through taxes they are continuing to pay for protecting oil supplies with their armed forces. Not only were billions of dollars spent in protecting the oil but lives were lost as well. Reliance on Middle East oil also creates a danger of fuel price shocks or shortages if supply is disrupted. Today, about one-third of US oil comes from the Middle East. By 2030, if the US does not change our energy policy, they may be relying on Middle East oil for two-thirds of their supply.
Nuclear Power
Present prices [of raw uranium] are at an all time low, less than $10 per pound. The reason is that some very rich uranium deposits have now been found in Canada: around 3% ore compared 0.2 %, which is the richest U.S. ore. Australia is also producing low cost uranium.
Fuelling a reactor for one year requires about 350,000 Ib of raw uranium to produce about 1,000,000 KW of electricity for about 7500 hours. At $10 per pound, this is $3.5 E6 / 7.5 E9 KW-h, or 0.04 cents per KW-h. (1 KW-h = 3,413 Btu) 18
Nuclear power plants are one of the most economical forms of energy production. Fuel costs for an equivalent amount of power run from 1 /3rd to 1 /'6th the cost for fossil fuel production, and capital and non-fuel operating costs are roughly equivalent, resulting in the overall cost of nuclear generation of electricity running 50% to 80% that of other sources. This is in spite of the fact that capital costs have been hugely inflated due to lawsuits, court injunctions, and other delaying tactics used by individuals and organizations opposed to nuclear power.
Uranium is a fairly common element on Earth and was incorporated into the planet during the planet's formation. It is therefore Uranium is originally formed in stars. Old stars explode, and the dust from these shattered stars aggregated together to form our planet. Uranium-238 has an extremely long half-life (4.5 billion years) and, therefore, is still present in fairly large quantities. U-238 makes up 99 percent of the uranium on the planet. Uranium-235 makes up about 0.7 percent of the remaining uranium found naturally, while uranium-234 is even more rare and is formed by the decay of uranium-238. (Uranium-238 goes through many stages or alpha and beta decay to form a stable isotope of lead, and U-234 is one link in that chain.) Unlike fossil fuels, this is a source of energy that is not going to run out in the foreseeable future.
There are however problems with mining Uranium. Today, most Uranium mining is done with injection wells, which pump fluid through the geologic formations where the mineral is found. Production wells then bring the Uranium-bearing solution to the surface. Called solution mining, this process can contaminate groundwater, which must then be pumped out and disposed of by injection into deep formations below freshwater aquifers.
Uranium used to be strip mined with technology similar to that used in coal mining. These uranium strip-mine operations created large areas requiring remediation. Large tailing ponds have been created to contain the radioactive materials. These ponds may pose a long-term threat to surface water and subsurface aquifers because they are subject to leakage. Federal law in the USA requires the tailing ponds, which contain materials that will remain radioactive for more than 1,600 years, to be covered so that rainwater does not mix with the radioactive waste. These pond coverings may be eroded over time by water and wind, which could allow radium to escape into the atmosphere. The ponds must be monitored for centuries to ensure that they are properly containing the radioactive waste.
Comparison
Despite the relative ease with which fossil fuels are extracted, nuclear energy has a massive advantage in terms of supply. Uranium is also becoming very cheap as developments in extraction technology make it easier and safer to attain.
Conclusion
At the start of this report I stated that the ideal power source will produce the largest amount of energy achievable at an affordable cost, with as little environmental pollution as possible. It appears that the nuclear power option fits this model the closest.
Uranium is both reasonably cheap to attain and is capable of producing a very high amount of energy. Fossil fuels are also cheap, but do not even come close to matching nuclear energy in terms of amount of energy produced.
The only major worry over nuclear power is the potential for a catastrophic accident. The results of such a disaster are unpredictable. The impact of fossil fuels on the environment is understood far better. However, another new scientist report suggests, "No deaths have so far been contributed to nuclear power plants in the UK. There have, however, been deaths and illnesses attributed to the release of toxic gases into the atmosphere due to the use of fossil fuels."
It seems that the technology of nuclear power is now very well understood, and with that now very safe. However, only time will really tell.
Nuclear power is the best source of energy for the present day and the foreseeable future. However, will there be better alternatives available in the not too distant future?
Future possibilities
Sewage turned into hydrogen fuel
Waste from sewage plants could be transformed into clean hydrogen fuel with high efficiency using new processing technology devised in Europe.
The process involves extracting hydrogen from "wet" waste, i.e. that which contains large amounts of water, such as sewage or paper mill waste. Although this sort of waste is abundant extracting hydrogen from has required a large amount of energy, making it inefficient.
But researchers in the Process Technology Group at Warwick University, UK, as well as a number of European companies, claim they have dramatically improved the efficiency.
"Warwick's Ashok Bhattacharya says the new system could be twice as energy-efficient as existing systems, which are typically around 20 per cent efficient. "We 're able to get much more hydrogen out," Bhattacharya says.
John Brammer, at Aston University, UK, agrees that most existing techniques are not efficient at extracting hydrogen: "An improvement of that order would be worth having. It would address the main problem in hydrogen production.""
- Taken from a report in "New Scientist" magazine.
However, the method has so far only been tested in the laboratory. Bhattacharya admits that its real energy-efficiency will not be known until a prototype has been developed. The group has just received £2.5 million of European funding to do
this.
Natural gas
Whist still not suitable for large scale power production, Hydrogen can be used to generate energy cleanly and efficiently through "fuel cells". These could eventually provide an alternative to fossil fuels for powering cars and homes.
The new process begins with turning waste "biomass" into hydrogen, methane, water, carbon monoxide and carbon dioxide, using standard gasification techniques that involve heat and pressure. But further hydrogen is then produced by also breaking down the methane and water, says Bhattacharya, with the aid of a nanocrystalline catalyst.
The process can be run continuously because pure hydrogen is extracted through a palladium-coated ceramic semi-permeable membrane that blocks other gases. If the hydrogen was not removed the reaction would reach equilibrium and stop. Bhattacharya adds that the heat efficiency of the new system has also been significantly improved.
The team expects to have constructed the first prototype, with the capacity to generate as much fuel as a petrol "gas" station, by 2005. So perhaps there will be better alternatives in the future?
Sources
* http://www.seabrookstation.com 1
This is a reliable source as it comes straight from the experts at an American power station. It may have been, however, that statistics and facts were manipulated to gain a commercial advantage. This was investigated to the best of my ability and was not found to be the case.
* http://library.lhinkguest.org/ 2
When investigating the reliability of this source was found no longer to exist on the internet. However, similar facts and figures on the internet are available and I found another a table at http://www.nucleartourist.com which matches the original table very well. Some additions were made to the table according to my new source, which appears to be very reliable as it was written by a professional engineer with a host of qualifications and industrial experience, including Membership of the American Nuclear Society Professional Engineer Exam Committee. There is a very detailed "about the author" page which lists all of the author's credentials.
* http://erhs.smjuhsd.k12.ca.us 3
This is an American high school's website that, for a short period, contained a report one student had written on nuclear energy. While not entirely relevant, it was the source that originally introduced me to the concept of "mass defect." I later found out more on Mass Defect from my Teachers and www.howstuffworks.com
* Advanced Physics - Adams / Allday - ISBN: 0199146802 4
A reliable textbook written to compliment a-level specifications. Recommended by my teachers.
* http://www.howstuffworks.com/
This was the source I mainly used to cross reference my other sources. It is a very widely respected and used website with a very good communications set up, designed so people can rectify mistakes in their articles. They also supply links to more information on your selected topic. Information on this site is always very accurate, and in any cases where mistakes or discrepancies occur they are usually rectified within days. It is not uncommon for professors and experts to browse this site and send in any changes. Where this does happen the site gives information on anyone who sends in any changes including their credentials.
* http://www.eia.doe.gov 5
* http://www.ucsusa.org/ 6
A website which allows scientists to debate and discuss discrepancies in a variety of scientific topics. They provide links to case studies and statistics to support their articles. Although often a little biased, this is a very reliable site.
* http://pw .netcom.com 10
A facts and figures website that presented information on SI units.
* http://www.nirs.org 9
A scientist-owned website dedicated to publishing accurate detailed information.
* http://www.newscientist.com11
I used this website mainly to check anything I discovered on http://www.ucsusa.org/. New Scientist is slightly better at discussing both sides of an argument so provided a less biased view and was always very accurate scientifically.
* http://www.tennesseevalleyec.com12
A site which provides a service that links remote reports from other websites about any current news and information about energy and energy production. Often links to internationally renowned news services such as CNN so is reasonably reliable in terms of accuracy.
* http://www-formal.stanford.edu 13
Contained a report written by a University professor that suggested the Chernobyl power plant was built incorrectly. This report was, however, dis
* http://www.anawa.org.au/15
* http://www.citycollegiate.com 16
* My teachers
* Energy for Life: Nuclear Energy - Robert Snedden - ISBN: 043114641
All references were cross referenced with various other sources (or each other) and any discrepancies that were found are mentioned in the report. Where there is no mention in the report of a discrepancy for a particular source it can be assumed that the reference has been checked and verified accordingly.
