Riley.Pascoe.wiki.spring.2011


 * Nuclear Fission**

|| Nuclear Fission as Paris Hilton would see it || There is a major crises in today's world when it comes to the use of fossil fuels and energy production. The problem we have is that the worlds dependence on oil is getting out of hand. We use oil for everything in our daily lives. We use it in our cars, homes, and workplaces. At the rate in which the world is headed we only have enough oil to last 42 years if we continue constant at out current pace. Oil is currently used for thirty seven percent of all the worlds energy supply.
 * Nuclear Fission as a Chemist may see it

Overall, there are many other sources of energy that we can use to to create electricity to power many of today's necessities like cars, factories, and homes. Nuclear Fission is dangerous but can provide electricity to to continue our daily lives and relieve us of our dependence on oil.

The driving force behind the energy crisis is that most people do not understand that there is even a crisis. Many people go through their lives thinking about there day and what lies in the near future or they think about the weekend. No one ever says to themselves "Hey, I wonder how much oil will be left in the world in the next thirty or forty years". No one will no until the problem hits, just like the most recent economic crash. People in today's world keep living until a problem hits then we try and solve it. If we don't start working on the problem now it will be to late. Currently there are no real solutions being suggested to solve the energy crisis. People right now are focusing more on the problem of global warming but not as much as the energy crisis


 * How does Nuclear Fission Work?**

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Nuclear fission is considered to be the heart of the reactor. While older plants burn fossil fuels, nuclear plants depend on the existing heat that occurs during nuclear fission. Nuclear fission is when one atom splits into two atoms and then releases energy. Nuclear fission is something that naturally happens everyday and is the most commonly used nuclear reaction for power generation. Nuclear fission produces heat, and this is because when you add all the masses together, the original mass is not what it comes out to, but there is actually a loss of mass, which is considered to be the heat and electromagnetic radiation produced during nuclear fission, and the outcome is large amounts of energy that can be utilized for power. Nuclear fission produces neutrons which can then be captured by other atoms to continue the reaction, also known as a chain reaction, with more neutrons being produced during each step. If too many neutrons are being generated, then the reaction can get out of control, which is how an explosion can then occur. Uranium is a common element on Earth, and their a plethora varieties of uranium, but uranium-235 is the most important in the production of nuclear bombs and nuclear power. How uranium-235 works, is it decays naturally by alpha radiation and it throws off two neutrons and two protons which are bounded together. Uranium-235 is also one of the few elements that can undergo induced fission. The decay of a single uranium-235 atom releases around 200 MeV (million electron volts), although this may not seem like much, there a lots or uranium atoms in just one pound (.45 kilograms) of uranium. This graph compares the number of daughter products produced by the fission of uranium-235 and those predicted by this modified lattice model. Two algorithms were used to determine the number of daughter products that might be expected when using this model. An agreement between the three curves indicates that some anomalies are probably the result of bonding interaction not accounted for when using a generalized simulation of how the bonds separate along the weak bonding layers.

The energy released during the fission process is really fusion energy.
 * FUN FACT!**

23892U+ 10n a 23992U a 23993Np +0-1e Even thought this was supposed to happen it didn't What really happened was that : 23592U +10n A 14256Ba +9136 Kr +3 10n +energy This means that many light atoms were detected and the possibility of a chain reaction became present.
 * Determine the amount of CO2 it produces or inhibits**


 * Nuclear Fission's World Energy Supply**

There are now some 435 commercial nuclear power reactors operating in 30 countries, with 370,000 MWe of total capacity. They supply 16% of the world's electricity, as base-load power, and their efficiency is increasing.

In March 2011, the approx. US $ cost to get 1 kg of uranium as UO2 reactor fuel was approximatly
 * = Item ||= Cost Element ||= Nuclear ||= Coal ||
 * =  ||=   ||= $/Mw-hr ||= $/Mw-hr ||
 * = 1 ||= Fuel ||= 5.0 ||= 11.0 ||
 * = 2 ||= Operating & Maintenance - Labor & Materials ||= 6.0 ||= 5.0 ||
 * = 3 ||= Pensions, Insurance, Taxes ||= 1.0 ||= 1.0 ||
 * = 4 ||= Regulatory Fees ||= 1.0 ||= 0.1 ||
 * = 5 ||= Property Taxes ||= 2.0 ||= 2.0 ||
 * = 6 ||= Capital ||= 9.0 ||= 9.0 ||
 * = 7 ||= Decommissioning & DOE waste costs ||= 5.0 ||= 0.0 ||
 * = 8 ||= Administrative / overheads ||= 1.0 ||= 1.0 ||
 * = Total ||=  ||= 30.0 ||= 29.1 ||
 * ~ Uranium: || 8.9 kg U3O8 x $146 || US$ 1299 ||
 * ~ Conversion: || 7.5 kg U x $13 || US$ 98 ||
 * ~ Enrichment: || 7.3 SWU x $155 || US$ 1132 ||
 * ~ Fuel fabrication: || per kg || US$ 240 ||
 * ~ Total, approx: ||  || US$ 2769 ||

At 45,000 MWd/t burn up this gives 360,000kWh electrical per kg, so fuel cost is about .77c/kWh Because uranium is so abundant and cost are so little effective there would nver be a problem if the price increased there wold be no spike in price like the many other fuel options



Also once processed, uranium and plutoniium that has be used can be resused to create more reatcions taht will save save money and create more electricity

A Finnish study in 2000 also compared the nuclear fission cost to the electricity costs:

this chart and the graphs show that a doubling of fuel prices would result in the electricity cost for nuclear rising about 9%, for coal rising 31% and for gas 66%. Gas prices have since risen significantly. The change for nuclear is a small amount compared to that of coal and gas. This shows how much more effective nuclear fission can be over other sources of energy.

The beginning process in the nuclear reactor begins with the fuel. The fuel that is gernerally used is uranium 235 which is recieved as pellets. These pellts are placed in long tubes that are then bundled together. The tubes or rods that they are placed in are generally 12 feet long. The grouping of these rods is called the fuel assembly. The first thing that happens to start the process of producing electricity is to split the atoms. The process of splitting atoms is called fission. To start the collision the the urannium is collided into a neutron. Once the first collision is madeit sets off the chain reaction. Once the chain reaction starts it keeps going until the fuel is all gone. When the reaction is created it is usually controlled by rods being inserted to absorb the neutrons taht would continue the reaction. This creates lots of heat This reaction of the uranium creates heat which heats the water in the first system. This first system is the first of three in the process. The water water is heated up in a pressurizer. The reason to have the pressurizer is to keep the water frm boiling. During this process you want the water to stay hot but not boiling. The boiling water then passes through a series of tubes. This shell and tube heat exchanger is the steam generator. The boiling water goes through the tubes and heats up the surrounding water. The surrounding water in the steam generating stage is then turned to steam. Where the water is turned to steam is the secondary water system. This newly created steam then travels through pipes. The piping system then makes its its way to connect the steam to a turbine. The steam goes through the turbine that spins a generator. the gernerator then spins a magnet which in turns creates electricity. Then after the turbine the water needs to be cooled so it can be created into steam again. To cool this water a separate line comes in from a lake or cooling towers and runs
 * How do nuclear reactors work to create energy?**

through a series of tubes that cool the water taht has come from the turbine. The water that was used for coooling is then run back to where it came from. The cooled water then makes its way back to the second water stage to be reheated into steam and then repeate to make more electricity

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One of the most interesting problems regarding nuclear physics is the fission of heavy elements into asymmetrical daughter products. This graph represents the number of daughter products produced and is shown using a logarithmic scale.

When a heavy nucleus undergoes spontaneous-fission, the production is not symmetrical, which under any regular circumstances would be expected to occur. Regardless of the heavy nuclei that under go fission, the fundamental distribution of isotopes in the heavy fraction of daughter products is essentially the same. The heavier the nuclei under going a fission, the more massive the center of the lighter daughter products becomes. The center of the lower mass lob increases in direct proportion to the mass of the fissionable elements. There must be a basic fundamental aspect about the nuclear structure that is coincident with a ass represented by the upper lob or heavier daughter products with a mass of about A = 134 to 144 for an average of A = 139 or 140

Much of og the waster that is created from nuclear reactors as a bi-product is considered high lever radioactive waste. Most people in the industry call it (HLW) for short. When something isn considered a high level nuclear waste, it meanst hat it must be permanatly contained. If the nuclear waste is reprocessed it will usually contain a large amount of liquid. This liquid contains high levels of nuclear fisson by products. To store the bi products of the nuclear fission. Scientist use a process called vitrification. Vitrification is a process that solidifies the material that came from the nuclear fission reaction. This project iis usually done in a glass matrix. These solids that are created throught the vitirfication are considered a high level waster product. These ores created have a very high radioactivty and would take about 10,000 years before it would return to a level that is generated in its original form. Another type of radioactive waster that forms is is call transuranic. This type is also called TRU waste. The differenence between this waster and the high lievel radioactive waste is that the transuranic waster does not generate intese radioactivity and heat. Also the TRU waster is a type of alpha decay which means it gives of alpha radiation. Alpha radiation is the smallest type of radiation. Which can be blocked by a thin sheet of paper. This Type of waste also has a larger halflife than HLW which mean it takes longer to decay. This type of waste usually is creataed in a lesser quanity that the high level radioactive waste.  After creating this solid waste it must must be stored. One prolblem that occurs during storage is that it constantly will give off intense light and radiation. This requires a lot of money to spend on dealing with this. To deal with this there must and great amount of shielding and cooling. There is a necessity to cool be cause it can heat up the area around it significantly and if it gets to hot there could be a possiblitilty to explode. There is also a neccesity to shield the waste greatly. This is because the waste is still decaying. While it is decaying it is still emiting particles. These particles must be blocked so they do not affect the atmosphere or the environamental settings like rivers and wildlife. Most of the time the waste is left in special chambers that are engineered to high standards where the waste over time will decay and be easier to dispose of. The waste is usually left for a few decades. That means that waste from our generation may not be ready to be disposed of until the next generation. Here is a picture of a special design that the waste will be stored in. The waste is goes down and into giant tunnels below the service where they have ventialtion and also a serivce shaft.
 * __What happens to all that waste __**

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==== For now the disposal of waste underground in these bunker type places are okay. Although most peole do not believe that it is okay for us to dipose of our nuclear waste for th efuture geneations to take care of. Although it is not an urgent issue to face right now, in the fute it will become a major issue that the government will need to decided on how to deal with our waste from nuclear power plants. Besides storing it underground people have came up with similar ways to store the waste. these other areas include under the seabeds, in areas covered by glaciers, sending it into space, or even reusing it in other nuclear reactions. ====

 When storing undergroung you cannot just put the waste down there. Beofre this is possible you must do a few things. One you must turn the waste into something that will not leech out. This is why the nucleat fission waste is turned into a solid form and put into a glass matrix. THe nexxt step tp be able to dump the waste underground is to put the waste into containers that will not corrode and allow the waste to fall out of th econtainer. Material must be surrounding the waste so nothing can seep through into groundwater. This is called backfill. the finla thing is that the waste needs to be seaparted form the enviornment of the humans soo it cannot contaminate the drinking water supplies

Notable Nuclear Accidents


 * On October 7, 1957, a fire occurred in the Windscale Plutonium Production Reactor near Liverpool, England. It spread radioactive material throughout all the countryside and as a result, about 39 people died of cancer.
 * In 1957 There was an explosion in Russia in nuclear waste tanks. This spread radioactive material and forced and evacuation in Kasli, Russia.
 * On January 3, 1961, an experiment reactor in Idaho killed three workers. These are the only deaths in United States reactor operations.
 * On January 21, 1969, a coolant breakdown from a reactor in Switzerland resulted in the release of large amounts of radiation into a cavern, which was later eventually sealed.
 * On March 22, 1975, a technician checking for air leaks with a lighted candle and he ended up causing a 100 million dollar.
 * On March 28, 1979, the worst commercial nuclear accident in the United States occurred as a series of mistakes led to a loss of coolant at the Three Mile Island reactor in Pennsylvania. This resulted in a 12 day crises and thousands of people living nearby left the area and radioactive water and gases were released.
 * On February 11, 1981, 8 workers were contaminated when over 100,000 gallons of radioactive coolant leaked into contaminated buildings in Tennessee.
 * On January 6, 1986, a cylinder of nuclear material burst after being improperly heated at a plant in Oklahoma. Just one worker died but 100 were hospitalized.
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">On April 26, 1986, there was considered to be the worst accident in the history of the nuclear power industry. Fires and explosions were the result from an experiment in Kiev, USSR. It left at least 31 people dead in the immediate aftermath and spread significant quantities of radioactive material all over Europe. An estimated 135,000 people evacuated the area and were homeless for years. Tens of thousands of excess cancer deaths were a result and increased rate of birth defects occurred.

There are many reasons why nuclear fission is considered a great energy source. The first aspect of nuclear energy is the fact that it is reliable. It is always available to be used at all times of the day. Being able to use nuclear power all day long makes it better than wind and solar power. This is because it is not always windy everyday and if it is windy it may not be strong enough to generate a lot of electricity. Also it is better than solar power because the sun is not up the whole day. As the earth rotates the sun will rise and fall over our solar panels which makes them useful seventy percent of the time. Another good aspect is that in each small amount of nuclear energy it is more powerful than coal and fossil fuel. Because of all the potential energy stored in this source when the energy is created, only a few tons can carry just as much energy as a couple hundred tons of fossil fuels and coal. With this we could also spend less energy on the transportation of this energy because we would not need to fill trains or tankers like we do on a daily basis for coal and fossil fuels. Also, the waste emitted from nuclear power does not affect the environmental changes as much as end products of the burning of coal and fossil fuels. Even though that the waste from a nuclear reactor is permanent as a solid the combined amount of waste compares to be less than that of the gaseous emission from the burning of coal and fossil fuels. With the waste not being a gas it does not contribute to global warming without contributing to global warming it can be considered by most people to be less harmful. The only problem is dealing with the waste after its created.
 * What are the best aspects of Nuclear Fission**

If a massive nucleus, such as Uranium-235, were to break apart then there will be a net field of energy because the sum of the masses of the fragments will be less than the mass of the uranium nucleus. If the mass of the fragment is equal to of greater than that of iron, then the nuclear particles will be more tightly bound than they were in the uranium nucleus and that decrease in mass comes off in the form of energy. The fission of Uranium-235 in reactors is triggered by the absorption of a low energy neutron, often known as a "slow neutron" or a "thermal neutron."
 * Uranium-235**



Uranium 235 Fission: In one of the most remarkable phenomena in nature, a slow neutron can be captured by a Uranium-235 nucleus, rendering it unstable toward nucleus fission. A fast neutron will not be captured, so neutrons must be slowed down by moderation to increase their capture probability in fission reactors. A single fission event can yield over 200 million times the energy of the neutron that triggered it.



Uranium Fuel: Natural Uranium is composed of .72% Uranium-235, 99.27% Uranium-238, and a trace quantity of .0055% Uranium-234. The .72% Uranium-235 is not sufficient to produce a self sustaining critical chain reaction in the United States light water reactors, but it is used in Canadian reactors. For light water reactors, the fuel must be enriched to 2.5-3.5% Uranium-235. Uranium found as Uranium Oxide that when purified has a rich yellow color is called a "yellow cake." After reduction, the uranium must go through an isotope enrichment process. Even with the necessity of enrichment, it still takes only about 3Kg of natural Uranium to supply the energy needs of one American for a year.



In the 1930's, German physicists/chemist, Otto Hahn, and Fritz Strassman wanted to create transuranic elements by bombarding Uranium with neutrons. When they did this they thought that heavy elements would be created. That’s not what happended though. All of the products they formed were lighter and were stunned by it. Once they identified what they made they did not want to publish their findings. They did not want to publish the findings because they were stunned and couldn’t believe what that had done. They published the results in 1939, they came to the attention of Lise Meitner, who is an Austrian-born physicist who had worked with Hahn on his nuclear experiments before. When hitler invaded austria Lise Meitner was force to flee the country. She fled to the country of sweden. Here she had continued her work to figure out this nuclear bombardment theory. She was the first to realize that Hahn's Barium and other lighter products from the neutron bombardment experiments were coming from the fission of Uranium-235. Frisch and Meitner carried out further experiments. These further expirements showed that along witht the fission, two nuetrons were created for everyone that was used. This is when they realized that they could create a chain reaction using nuetron bombardment and create a lot of energy yields.
 * History of Uranium-235**


 * Quotes from Scientists**

"France generates a significant part of its energy requirements from fission reactors and these have achieved a perfect safety record. We build ours all differently." __ -Wilson Greatbatch __

<span style="background-color: transparent; color: #000000; display: block; text-align: left; text-decoration: none;"> "Nuclear fusion of light elements like hydrogen or helium would permit approaching the speed of light. It seems very attractive to refuel your space ships where the fuel is." <span style="background-color: transparent; color: #000000; display: block; text-align: left; text-decoration: none;"> -Wilson Greatbatch

<span style="background-color: transparent; color: #000000; display: block; text-align: left; text-decoration: none;"> "Rocket scientists agree that we have about reached the limit of our ability to travel in space using chemical rockets. To achieve anything near the speed of light we will need a new energy source and a new propellant. Nuclear fission is not an option." <span style="background-color: transparent; color: #000000; display: block; text-align: left; text-decoration: none;"> -Wilson Greatbatch

"It is hard to think of fissionable materials when fashioned into bombs as being a source of happiness. However this may be, if with such destructive weapons men are to survive, they must grow rapidly in human greatness. A new level of human understanding is needed. The reward for using the atom's power towards man's welfare is great and sure. The punishment for its misuse would seem to be death and the destruction of the civilization that has been growing for a thousand years. These are the alternatives that atomic power, as the steel of Daedalus, presents to mankind. We are forced to grow to greater manhood."
 * -Arthur Holly Compton**

"The technologists claim that if everything works [in a nuclear fission reactor] according to their blueprints, fission energy will be a safe and very attractive solution to the energy needs of the world. ... The real issue is whether their blueprints will work in the real world and not only in a “technological paradise.”... Opponents of fission energy point out a number of differences between the real world and the “technological paradise.” ... No acts of God can be permitted."
 * -Hannes Alfven**

"In the discussion of the. energies involved in the deformation of nuclei, the concept of surface tension of nuclear matter has been used and its value had been estimated from simple considerations regarding nuclear forces. It must be remembered, however, that the surface tension of a charged droplet is diminished by its charge, and a rough estimate shows that the surface tension of nuclei, decreasing with increasing nuclear charge, may become zero for atomic numbers of the order of 100. It seems therefore possible that the uranium nucleus has only small stability of form, and may, after neutron capture, divide itself into two nuclei of roughly equal size (the precise ratio of sizes depending on liner structural features and perhaps partly on chance). These two nuclei will repel each other and should gain a total kinetic energy of c. 200 Mev., as calculated from nuclear radius and charge. This amount of energy may actually be expected to be available from the difference in packing fraction between uranium and the elements in the middle of the periodic system. The whole 'fission' process can thus be described in an essentially classical way, without having to consider quantum-mechanical 'tunnel effects', which would actually be extremely small, on account of the large masses involved."
 * -Lise Meitner**

"No-one really thought of fission before its discovery."
 * -Lise Meitner**

"O. Hahn and F. Strassmann have discovered a new type of nuclear reaction, the splitting into two smaller nuclei of the nuclei of uranium and thorium under neutron bombardment. Thus they demonstrated the production of nuclei of barium, lanthanum, strontium, yttrium, and, more recently, of xenon and caesium. It can be shown by simple considerations that this type of nuclear reaction may be described in an essentially classical way like the fission of a liquid drop, and that the fission products must fly apart with kinetic energies of the order of hundred million electron-volts each."
 * -Lise Meitner**

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