Chemistry

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A 40 Year Old Breakthrough Comes to Light

By Stephen Miranda

Can a 40 year old mystery become a huge step in modern technology? In 1972, a researcher by the name of Takahashi made a grand discovery of iron nitride. It’s magnetic properties did very little but astonish until recently when a team from the University of Minnesota started to reinvestigate.

We use magnets everywhere in today’s technology. From storing files on a hard drive to electric car motors. This is why iron nitride is an important discovery: Following the trends of modern technology, everything from cell phones to desk top computers are quickly decreasing in size, and if we want to make them even smaller and convenient, we must find how to do what these computers do on a much smaller scale. Of course, this isn’t anything you shouldn’t already know, but we are running out of ways to decrease the size of our everyday electronic devices. Iron nitride seems to be as small as magnetic materials get. It comes in the form of an ultra-fine powder measuring only tens to hundreds of nanometers in diameter. Scientists even claim that it may even be approximately 18% more magnetic than the theoretical limits. Journalists at the Huffington Post claim that the most magnetic substance known to man before this discovery was an iron-cobalt alloy, but since then, iron nitride has seem to take its place as the “Holy Grail of Magnetism.”

When something is magnetic, it is because the rotation of the electrons in the majority of the atoms are spinning in one direction. There is, in a sense, only two ways for these electron clouds to rotate, and if more are rotating “up” than “down,” the object becomes magnetic.

Iron nitride is atomically arranged unlike anything scientists have seen before. With new x-ray technology, we are ably to see that one nitrogen atom has clustered 6 iron atoms around it along with another 2 filling in the gaps between the clusters.

Takahashi raves that this discovery could decrease the size of EV motors by 40% without compromising any power. Iron nitride would be around 60% more powerful than the existing magnets used today for these same purposes. The magnets used to today’s EV motors contain neodymium. Neodymium is a rare-earth metal that is produced in China. Neodymium’s price is starting to rise to points where large companies are readily seeking alternatives. Iron nitride is also very easy to produce because it is made from 2 extremely abundant materials, iron and nitrogen, unlike neodynium. Could iron nitride be the perfect substitution for neodynium?

Though it seems like the perfect breakthrough, iron nitride is not without its problems. The production process lacks refinement because, when produced, iron nitride also seems to produce a inconsistent amount of other compounds as well. Scientists are estimating that the material will start being mass produced by the year 2023 and already have agreements set up between the Toyota and Honda car manufacturers and if it begins to gain a larger following, it may improve the size of our technology drastically.

Works Cited

Edwards, Lin. "Iron-nitrogen Compound Forms Strongest Magnet Known." Iron-nitrogen Compound Forms Strongest Magnet Known. N.p., 22 Mar. 2010. Web. 18 Dec. 2012.

"Newly Discovered Magnetic Material 18% Stronger Than Any Other Known Magnet." The Green Optimistic RSS. N.p., n.d. Web. 18 Dec. 2012.

"Scientists Find Strongest Magnet Yet; Could Fe16N2 PM Motors Be Next?" Scientists Find Strongest Magnet Yet; Could Fe16N2 PM Motors Be Next? N.p., n.d. Web. 18 Dec. 2012.

Vieru, Tudor. "Giant Saturation Magnetization Magnetic Material." - Softpedia. N.p., n.d. Web. 18 Dec. 2012.

Chemistry of materials has shaped our past and present by the types and sizes of techonolgy that we have at our disposal. This technology that we have is also effected by the chemical structure of what iit is made of. For example, fire retardant material doese not ignite because of it's chemical properties. In the future, our technology will change with the discovery of new chemical compounds and structures. Technology will get smaller, safer and overall more powerful.


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Energy and Place

Elliot, Jasper, Stephen, Kaleb, and Dusty's Joint Scientific Statement

Elliot Mink:

NUCLEAR POWER                                                                                                Elliot Mink

Although Global Climate change has been an argued fact for years, it is now an accepted fact by an overwhelming number of scientists. Our planet is warming due to human activities and our energy demands. One contributor to the change in climate is the greenhouse effect and greenhouse gasses. The greenhouse effect is when the short, visible, light wavelengths from the sun pass through our ozone and into our atmosphere. The wavelengths then get turned into longer, infrared wavelengths when they re-radiated from the earth. These infrared rays are then unable to get back out of our atmosphere, because the greenhouse gasses that are held within our ozone absorb the infrared rays. In all, “the greenhouse effect is the trapping of excess heat by the rising concentration of greenhouse gasses in the atmosphere” (Nave, Greenhouse gasses). Many greenhouse gasses are naturally occurring in our atmosphere like water vapor and carbon dioxide, yet some are synthetic like chlorofluorocarbons. But whether the greenhouse gas is manmade or natural, to meet our energy demands, the human race is increasing the amount of greenhouse gases in our atmosphere. Water vapor is the most abundant greenhouse gas in our atmosphere. Although the increase in water vapor is not a direct result of industrialization, as the earth gets hotter more water evaporates creating even more greenhouse gases. Carbon dioxide is a naturally occurring gas, but the burning of coal, oil and other natural gases has changed carbon from its solid storage to it gaseous state. According to the National Oceanic and Atmospheric Administration (NOAA) National Climatic Data Center, the atmospheric concentration of CO2, “prior to the industrial revolution, concentrations were fairly stable at 280ppm. Today, they are around 370ppm, an increase of well over 30 percent”(1). The next most abundant greenhouse gas is carbon dioxide. Carbon dioxide has increased in our atmosphere due to our energy needs and burning various natural gases. According to the National Oceanic and Atmospheric Administration (NOAA) National Climatic Data Center, the atmospheric concentration of CO2, “prior to the industrial revolution, concentrations were fairly stable at 280ppm. Today, they are around 370ppm, an increase of well over 30 percent”(1). The next gas on the list is methane, then tropospheric ozone, nitrous oxide, and then chlorofluorocarbons and Carbon monoxide. The reason the previously mentioned gases are in fact greenhouse gases, is due to the fact that they are responsive to infrared radiation. When infrared radiation comes in contact with a CO2 molecule, per say, the CO2 molecule will vibrate and stretch to absorb the heat. Yet O2 does not have this quality and infrared radiation does not cause the molecule to vibrate because the bond length is not at the appropriate length to harness infrared radiation, therefore heat is not absorbed. When CO2 is hit by the infrared radiation it bumps up and vibrates at a different orbital. When the molecule drops back down it releases the absorbed infrared radiation in a random direction. Some of the infrared may end up exiting the atmosphere, but some will be kicked back to earth keeping the heat within our atmosphere.

Every type of power plant releases some type of greenhouse gas at some point in its life cycle, but the process of burning fossil fuels is a main contributor of CO2 emissions. During any combustion reaction CO2 is a product. So the burning of any fuel will cause an increase of CO2 which is a greenhouse gas, and greenhouse gases absorb heat and cause global warming.

To understand how many greenhouse gases a nuclear power plant, and a coal power plant releases you must look at both the number of emissions while it is running and the process of acquiring the uranium, processing of the ore and the disposal of the waste. This method of calculating the amount of greenhouse gases that are emitted from a plant is what researchers call, “looking at the entire life cycle. Figure 1 shows one life cycle of a nuclear power plant.

Figure 1: Nuclear Power Plant Life Cycle

This same approach must also apply when looking at the amount of greenhouse gas emissions of a coal fired power plant. Figure 2 shows one full life cycle of a coal fired power plant.

Figure 2: Coal fired power plant life cycle

In the two diagrams the acquisition of the products is highlighted, the actual use of the power plant and the end use of the leftover products. Yet both diagrams differ from each other, and this remains true when studies are conducted to evaluate the true emissions of a power plant. Despite this discrepancy on average coal powered power plants produce about 888 tonnes of CO2e/GWh and nuclear power plants produce 29 tonnes of CO2e/GWh. So despite some fluctuation in the data nuclear power plants clearly produce less CO2, and according to the World Nuclear Association, “Lifecycle emissions of coal generation are 30 times greater than nuclear” (9).

A large concern with nuclear power is the cost of actually building and running the plant due to the fact that one has not been built for 30 years. All estimates are very scattered and there is a lot of conflict in the actual cost of the powerplant and the cost per killowat of energy. According to Synapse Energy Economics, Inc., the total cost of a nuclear power plant: “will be in the range of $5,500/kW to $8,100/kW”. And the cost of one power plant will be, “between $6 billion and $9 billion for each 1,100 MW plant” (David Schlissel and Bruce Biewald, 2).

The most common way to mine uranium is through open pit mining. Blasting is used to reach ore deposits deep into the ground. Because of this deep mining miners are very close to, and are constantly around uranium deposits. Another method is through uranium mining. If the deposits are too deep then tunnels are dug deep into the earth for extraction. There are many other methods that also require chemicals to extract the element form the ore. The main fuel for nuclear fuel is uranium, and the mining and refining of uranium comes with many health risks. The mining of uranium has had a history of causing lung cancer and other various diseases. A bi-product of uranium is radon gas, and high exposure to radon gas has proven to cause an increase in lung cancer. Also when mining not all of the substance is used and large waste deposits are created. From these deposits radioactive material can travel, and increase radiation levels all around the area. The last issue is just the issue of another mine. Open pit mines are very intrusive to the local area and leave giant craters in the ground. In many cases these pits are not refilled and radiation could continue to leak into our atmosphere.

http://www.ncdc.noaa.gov/oa/climate/gases.html

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/grnhse.html

http://www.elmhurst.edu/~chm/vchembook/globalwarmA5.html

http://www.world-nuclear.org/uploadedFiles/org/WNA/Publications/Working_Group_Reports/comparison_of_lifecycle.pdf

http://www.nirs.org/climate/background/sovacool_nuclear_ghg.pdf

http://en.wikipedia.org/wiki/Uranium_mining#Health_risks_of_uranium_mining

Jasper graves:

How does nuclear fission work? You should describe the process in general and then describe the exact mechanism of one fission process (i.e. U-235 or Pu-239).

                       Nuclear fission is the process it takes to set off a nuclear chain reaction. During the 1930 scientists discovered they could start a nuclear reaction by slamming a larger radioactive isotope with a smaller one, often a neutron. This sets off a chain reaction that releases a very large amount of energy. This process is the same as what happened in the atomic bomb that was dropped on Hiroshima. This energy comes directly from matter. When beginning fuel in a nuclear power plant is weighed and the spent fuel is weighted at the end of the process, the beginning fuel is slightly heavier. The matter is transformed directly into energy. To harness this energy, a nuclear power plant slows the fission reaction so that heat is released incrementally.

                       The true mechanics that are happening behind fission are when atoms split. When as the neutron slams into and is accepted by the nucleus of uranium-235 the atom breaks into two lighter atoms and two to three more neutrons. This produces an isotope thorium-232 as the final product.

These lighter atoms are now decayed and cannot be used any more in this reaction. The neutrons go on to  get more uranium atoms and set off more decay. One atom decay of uranium 235 releases 200 MeV (million electron volts). Nuclear power plants use uranium that has been enriched, this means that there are more atoms of uranium 235 than what normal uranium would hold, uranium is usually enriched by 3% for the creation of electricity.

What safety risks accompany the use of nuclear power?

o How much radiation is the surrounding environment subjected to from a properly function nuclear power plant?

o What risk for nuclear meltdown exists in light water reactors in the United States?

o What safety features are being built into future light water reactors?

o What are potential risks to nuclear power plants from terrorist attacks?

The biggest problem with nuclear power plants, are over heating of the reactor. This can occur when the reactor is allowed to perform fission too quickly or the cooling water is not properly circulated. Together nuclear reactors have only had three failures over there 14,500 year cumulative lifespan. Although nuclear reactors can melt through their shielding and release radioactivity they cannot  explode, the uranium is not enriched beyond 5% in commercial reactors and thus does not have the same destructive power that a bomb has. In the Chernobyl accident, the containment vessel did explode but this was the result of the expansion of superheated steam. The pipes in the concrete expanded and exploded. The use of smaller pipes with multiple release valves is designed to reduce this risk.

1. People living within a 50 mile radius will only receive an additional .01 millirem per year compared to average. In perspective, the average American citizen only receives about 300 millirem per year.

2. The clean air task force released a report specifying reasons why a light water reactor is less likely to experience a nuclear meltdown than other standard models. In small light water reactors, the cooling water can be stored in cooling tanks above the facility and not require pumping in the case of an emergency. The entire plant can also operate off the power grid due to the low requirements for power, batteries can maintain the entire system for a finite period of time. In a small light water reactor the cores and containment shields are kept underground, they are also pressurized and tested to withstand an airplane crash. All piping is routed through several backup systems and none of the pipes are larger than a few inches in diameter. This means that damaged pipes will not result in large coolant loss failure. The cooling containment in light water nuclear power plants is larger so that in the event of an earthquake the core will have room to shift without cracking.

3. Nuclear reactors now have three safeguards against nuclear meltdown, First, the control rods monitor the level of reaction the core can produce at any time. Second, cooling liquid is pumped around the core so that heat is dispersed. Third, there is now a concrete containment shield around the reaction vessel that would protect the outside and the public if a meltdown were to occur. Fail safes have been installed in the system so that even if the main cooling pipe for the entire system were to completely break there would be backup systems to keep the core covered with water. "The US Nuclear Regulatory Commission (NRC) specifies that reactor designs must meet a 1 in 10,000 year core damage frequency, (This means that it would be acceptable for the core to undergo damage only once every 10,000 years) but modern designs exceed this. US utility requirements are 1 in 100,000 years, the best currently operating plants are about 1 in 1 million and those likely to be built in the next decade are almost 1 in 10 million." says the World Nuclear Organization.

4. Nuclear power plants are very resistant to terrorist attacks. Although due to public fear and superstition, any attempt to disrupt operations could lead to panic, if poorly televised. The only real method that could cause serious damage would be the use of large scale aircraft, crashed directly into reactors or water storage areas. Still, even this is unlikely to create the desired effect, the aircraft would have to directly hit the containment shell of the reactor to even crack it. The most damaging outcome if everything worked perfectly would be for the reactor to meltdown and fuse to the bottom of the containment vessel. Still, in this case, radiation would not necessarily leave the plant, it would be contained inside the shell of the reactor housing and below grade. Without some other form of propulsion, there would be nothing to force the radiation out into the world.

World nuclear association. N.p., 2013. Google. Web. 24 Apr. 2013. <http://www.world-nuclear.org/info/Safety-and-Security/Safety-of-Plants/Safety-of-Nuclear-Power-Reactors/>.

MARSTON, PhD, THEODORE U., DR. ANDREW C. KADAK, and DR. PER PETERSON. "The Nuclear Decarbonization Option: Profiles of Selected Advanced Reactor Technologies." Clean air taskforce. Non-Profit, Mar. 2012. Google. Web. 24 Apr. 2013. <http://www.catf.us/resources/publications/view/164>.

"Frequently Asked Questions (FAQ) About Radiation Protection." NRC:. Regulations.gov, n.d. Web. 28 Apr. 2013. <http://www.nrc.gov/about-nrc/radiation/related-info/faq.html>.

"Power Plant Safety Features." Power Plant Safety Features. FEMA, n.d. Web. 28 Apr. 2013. <http://emilms.fema.gov/IS3/FEMA_IS/is03/REM0404010.htm>.

"National Policy Analysis #374: Terrorism and Nuclear Power: What Are the Risks? - November 2001." National Policy Analysis #374: Terrorism and Nuclear Power: What Are the Risks? - November 2001. N.p., n.d. Web. 28 Apr. 2013. <http://www.nationalcenter.org/NPA374.html>.

"Nuclear Fission Basics." - For Dummies. John Wiley & Sons, Inc, 2013. Web. 28 Apr. 2013. <http://www.dummies.com/how-to/content/nuclear-fission-basics.html>.

Kaleb Johnson:

·         What is nuclear waste?  Describe in general and then characterize the nuclear waste of a standard light water reactor.

o    What radionuclides are typically in radioactive waste and in what concentrations?

o    What are the half-lives of the radionuclides found in radioactive waste?

o    What are the types of decay the radionuclides in radioactive waste undergo?  You may describe the entire decay chain or only the most relevant decay processes.

o    How much radioactive waste is produced by a typical light water reactor?

What are environmental and safety considerations for the storage of nuclear waste?

Sources:

1. "Radioactive Waste." NRC:. United States Nuclear Regulatory Commission, 18 Oct. 2012. Web. 16 Apr. 2013. <http://www.nrc.gov/waste.html>.

2. "Backgrounder on Radioactive Waste." NRC:. Unites States Nuclear Regulatory Commission, 4 Feb. 2011. Web. 16 Apr. 2013. <http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/radwaste.html>.

3. "Key Issues." Nuclear Energy Institute. Nuclear Energy Institute, n.d. Web. 18 Apr. 2013. <http://www.nei.org/keyissues/nuclearwastedisposal/>.

"Radioactive Waste." Wikipedia. Wikimedia Foundation, 18 Apr. 2013. Web. 18 Apr. 2013. <http://en.wikipedia.org/wiki/Radioactive_waste>.

"Uranium." Wikipedia. Wikimedia Foundation, 22 Apr. 2013. Web. 22 Apr. 2013. <http://en.wikipedia.org/wiki/Uranium>.

"Spent Nuclear Fuel." Wikipedia. Wikimedia Foundation, 19 Apr. 2013. Web. 22 Apr. 2013. <http://en.wikipedia.org/wiki/Spent_nuclear_fuel>.

"Uranium-235." Wikipedia. Wikimedia Foundation, 19 Apr. 2013. Web. 24 Apr. 2013. <http://en.wikipedia.org/wiki/Uranium-235>.

"Plutonium-239." Wikipedia. Wikimedia Foundation, 19 Apr. 2013. Web. 24 Apr. 2013. <http://en.wikipedia.org/wiki/Plutonium-239>.

"Plutonium-240." Wikipedia. Wikimedia Foundation, 19 Apr. 2013. Web. 24 Apr. 2013. <http://en.wikipedia.org/wiki/Plutonium-240>.

"Uranium-238." Wikipedia. Wikimedia Foundation, 19 Apr. 2013. Web. 24 Apr. 2013. <http://en.wikipedia.org/wiki/Uranium-238>.

"Light Water Reactor." Wikipedia. Wikimedia Foundation, 24 Apr. 2013. Web. 24 Apr. 2013. <http://en.wikipedia.org/wiki/Light_water_reactor>.

"Decay Chain." Wikipedia. Wikimedia Foundation, 19 Apr. 2013. Web. 25 Apr. 2013. <http://en.wikipedia.org/wiki/Decay_chain>.

Nuclear waste is a byproduct of nuclear reactors, fuel processing plants, and other institutions, such as hospitals. Nuclear waste is classified in two categories High and Low level waste. Low level wastes consist of radioactive wastes other than high level wastes and wastes from uranium recovery operations, the majority of these are materials that have been contaminated by radioactive material such as protective shoe coverings, clothing, rags ,mops, etc. High level waste usually consists of spent fuel rods from nuclear reactors. Spent fuel rods usually are made up of the following radionuclides: 3% U 235 and Pu 239, 1% Pu 240, and 96% U 238. The half-lives of the radionuclides are as follow:U-235 703.8 million years, Pu-239 24,100 years, Pu-240 6,563 thousand years, and U-238 which has a half life of 4.468 billion years.  Uranium-235 and Plutonium-239 are both part of the same decay chain , which mainly uses  alpha decay, that ends in the decay into lead-207. Uranium -238 and Pu-240 are both part of different decay chains which end in lead-206 and lead-208, respectively.The amount of waste produced by a 1000 Megawatt reactor is about 27 tons a year.

There are many considerations when considering the environmental the storage of nuclear waste. The main one is time because some of the  radionuclides in nuclear waste have half lives of thousands of years the area that the waste is going to be contained in has to last for a VERY long time because even a small leak could have major consequences of that if left alone for hundreds o if not thousands of years. The reason that nuclear waste has to isolated for so long is because the half lives of  the radionuclides in it are so long, such as U-235 which has a half life of 703.8 million years. Another concern is the  effect  on environment around the containment area should any nuclear waste escape. Ideally the environment around the containment area should be far away from any population centers and fragile natural habitats to reduce  the impact if the containment fails.

Dusty:

Explain the meaning of E=mc2 and the relevance of this relationship to nuclear power. Include a sample calculation that is relevant to a nuclear fission power plant. Make sure your explanation addresses the idea of conservation of mass and energy.

E = mc2 is a version of Einstein's famous theory of relativity which states that the energy of an object (E) is equal to the mass of the object (m), times the speed of light (c), squared. Einstein’s theory of relativity also states that no object with mass can travel faster than the speed of light in a vacuum. This theory basically states that the amount of energy released when an object traveling at any speed hits a brick wall, lets say, and the speed at which the object was traveling, along with its mass, are inversely related, this means that an object traveling quicker than another will require less mass than the other in order to create the same amount of energy.  

V represents the velocity of the traveling object, which can also be represented as the speed of light or c. The speed of light is simply the conversion between mass and energy released.

An object travelling more slowly will release less energy than one traveling close to the speed of light, however, an object traveling at 99% the speed of light will almost instantaneously explode and release the energy in it’s nucleus.

In a nuclear power plant, radioactive substances that store a lot of energy in their bonds are affected by shooting neutrons at them. When the neutrons are shot at them the neutrons are traveling at the 7% speed of light, however, these neutrons don’t have much mass. Rather, these neutrons traveling quickly act as the brick wall, which, when they hit a radioactive atom, break apart the binding agent of the nucleus, which has a bit of mass. So when the binding agent is broken, it turns from a solid to energy, and that is the energy released during a fission or fusion reaction. When they meet the radioactive substance releases the energy stored in its bonds and then the bonds break. Neutrons shoot in all directions at close to the speed of light, hitting other atoms of the same substance. The energy released in the splitting of the nucleus is great and therefore, we have a nuclear explosion. Nuclear power plants break these radioactive bonds on a daily basis and contain them, then using the energy released to heat water, creating water pressure, which then moves quickly through a turbine, which then creates electricity. The amount of energy created by these nuclear power plants is relative to the amount of fuel that they use.

What are emissions from nuclear power plants?

Nuclear power plants function by combusting radioactive substances via fission which is accomplished by hitting these radioactive substances with neutrons. This causes the substance to become unstable and release energy. The atoms that then explode release their neutrons which then hit other atoms, causing a chain reaction. These nuclear reactions are extremely violent and therefore need to be cooled, otherwise, the nuclear containment vessels would melt straight through the Earth’s crust, into the core.

To stop this from happening there are two cooling systems that are simply called the primary, secondary, and tertiary cooling systems. The primary coolant stays in the chamber that contains the fuel rods, the radioactive material, and all components of the core. This primary coolant gets very hot from the irradiation it receives and therefore needs to be cooled. The secondary coolant does this job. The secondary coolant cycles through the primary coolant and absorbs the energy in the primary, cooling it down, however, the secondary coolant then becomes so hot that it turns to steam and needs to be cooled. However, before the secondary coolant is cooled, the nuclear power plant utilizes this high pressured steam to create electricity. As the steam travels to the tertiary coolant it passes a turbine that it spins. This turbine is connected to a generator so as the turbine spins it activates the generator, creating electricity. The hot steam then goes into a tertiary cooling system where the hot steam is released through giant steam stacks. Therefore, the only waste products from a nuclear power plant are water, which is non-harmful to the environment, and radioactive waste which is.

The emissions from a nuclear power plant are fairly clean, however, the steps involved in creating a nuclear power plant are the more environmentally harmful parts of the process. Before power can be created we have to mine for Uranium or other radioactive elements that may be used in the fission process. This has an environmental impact because the land gets torn up, moved, trees are torn up, water systems are polluted, and radioactive dust is kicked up into the air. These are the larger impacts that nuclear power has on the environment. Also, we need to build nuclear power plants, which has it’s own environmental impact.

Optional Science Considerations

There are two waste cycles that occur inside a nuclear power plant. A nuclear waste cycle is simply the process in which occurs a decomposition of radioactive isotopes used in the nuclear fission process. The open waste cycle is what people usually think of when they hear about the use of radioactive fuel in a nuclear power plant. Lucidly speaking, this cycle begins by releasing a neutron into the reactor core which contains a radioactive isotope (the isotopes used vary). The neutron then hits a singular atom and causes a nuclear reaction called fission. When the neutron hits the atom the isotope becomes very unstable because of an increase in the atomic radius. This unstable element quickly decays, releasing neutrons which then hit other atoms of the same element, and the reaction then continues in the same manner. In this fuel cycle, the entirety of the radioactive fuel is reacted, then dumped. The closed waste cycle is essentially a one time use source of power. After the fuel is used it’s dumped (often into the same mine in which it was milled) and then replaced.

The closed waste cycle however, is more complicated, more efficient, and requires more sophisticated technology than the closed waste cycle. The open waste cycle is accomplished by means of changing uranium 235 and 238. Uranium 235 is the enriched form of uranium that is fissionable and used in the fission process. Uranium 238 on the other hand is not fissionable and used for fuel. In the open waste cycle process, both uranium 235 and 238 are used, however with less uranium 238 than 235. This technique begins by releasing a neutron into the uranium 235 (which the the fuel source used in the closed waste cycle). Then, the same procedure occurs as in the closed fuel cycle; the fissionable uranium 235 gains a neutron, becoming uranium 236, which then decomposes and becomes Barium 144 and Krypton 89. The uranium 236 also releases three neutrons. Unlike the closed waste cycle however, when the uranium 236 decomposes and releases its three neutrons, it enriches the uranium 238, creating plutonium 239. The enriched plutonium 239 is then fissionable, so when a neutron from the uranium 236 hits the plutonium 239, it becomes unstable and then decays into uranium 235, giving off four neutrons, which then hit other atoms of uranium 235, creating 236, and then the cycle continues. These cycles occur in what are known as breeder reactors.

    Breeder reactors are nuclear fission reactors in which the closed waste cycle occurs. They are called breeder reactors because they have the ability to create a fissionable fuel source, they breed nuclear fuel, in essence. The other type of reactor used in the nuclear fuel process is called a light water reactor. Light water reactors are the most commonly used type of reactor, simply containing water that flows around the core, cooling it, unlike breeder reactors. Light water reactors are reactors in which the water used to cool are not left under pressure, so the water then becomes hotter and boils. Breeder reactors still have water so that the fuel is cooled and doesn’t melt down, however, it contains less water than a light water reactor. This is because the a breeder reactor needs more energy to recycle the fuel source, so the fuel is cooled less and therefore, the core is much hotter. Heavy water reactors are very similar to light water reactors, however, the water in these heavy water reactors are kept under pressure so that the water contained within doesn’t boil, so there’s more energy inside the water, so things stay cooler.

    Fission is what happens in a nuclear power plant. Fission is accomplished by shooting a neutron into the body of an atom, making it unstable, and therefore, causing it to fissile and decay into two different elements, as well as releasing several neutrons. Fusion is when two atoms are smashed together, creating one new atom. This element, upon fusion, releases several neutrons because of the lack of stability within the atom. The mass of this new atom is less than that of the combined mass of the two atoms that were smashed together because of the release of neutrons.

                                                                      

Tucker, William. "Understanding E = Mc2." Energy Tribune RSS. Energy Tribune, 21 Oct. 2009. Web. 29 Apr. 2013. <http://www.energytribune.com/2771/understanding-e-mc2>

Kleiner, Kurt. "Nuclear Energy: Assessing the Emissions." Nature.com. Nature Publishing Group, 24 Sept. 2008. Web. 29 Apr. 2013. <http://www.nature.com/climate/2008/0810/full/climate.2008.99.html>

"Uranium-235." Wikipedia. Wikimedia Foundation, 19 Apr. 2013. Web. 29 Apr. 2013. <http://en.wikipedia.org/wiki/Uranium-235>

"Nuclear Fuel Cycle." Wikipedia. Wikimedia Foundation, 20 Apr. 2013. Web. 29 Apr. 2013. <http://en.wikipedia.org/wiki/Nuclear_fuel_cycle>

"Decay Chain." Wikipedia. Wikimedia Foundation, 19 Apr. 2013. Web. 29 Apr. 2013. <http://en.wikipedia.org/wiki/Decay_chain>

Stephen Miranda:

Describe the design of a light water nuclear power plant.

    A nuclear reactor is made up of several parts that all work together in giving us energy. The nuclear reactor is the center of the plant. The core produces heat by a process of nuclear fission. Inside the core are control rods which rise and lower to stabilize the speed of the nuclear reaction. These rods are made of carbon or neutron poison. This means that the rods themselves absorb neutrons. These rods absorb neutrons which means that there are less neutrons that can cause fission. The rods can be raised or lowered to control the rate of fission. When the control rods are lowered, a smaller amount of fission can happen. This is how the rate of power production is controlled. Primary coolant is pumped through the reactor, dispersing heat. Of course, the primary coolant absorbs a fair amount of the heat from the reactor and start to get really hot and must be cooled down itself. This brings the need for a full coolant consisting of the primary coolant, secondary coolant (to cool the primary coolant), and tertiary coolant (to cool the secondary coolant). The tertiary coolant is then piped to the cooling tower to completely cool itself. The primary secondary coolant, being water, turns to steam when coming into indirect contact with the primary coolant. This steam is guided toward a turbine, which spins with the force of the moving steam. The steam comes into indirect contact with the tertiary coolant and is cooled back down to its liquid state. The turbine is connected to an electric generator. The spinning motion of the turbine is then translated into energy by the generator.

There are several types of cooling towers that use different methods to complete their tasks of transferring heat out of the coolant. A dry cooling tower operates by transferring heat through something such as a tube into the air around it. Wet cooling towers use a process called evaporative cooling where the coolant is driven through more water, which evaporates, taking the thermal energy along with it. Fluid coolers are the most effective way of cooling the fluid. In these, the pipes holding the hot coolant are sprayed down with water along with a fan induced draft. When the reactor becomes too hot, it becomes less efficient. This is because the molecules are moving too fast and can possibly move past or even through each other if they are not moving at the right speed.

    Enriched uranium, which is a processed version of uranium hexafluoride, is used to make the fuel rods which provide the fuel for the reactor. These fuel rods can be used for about 3 operational cycles, which consist of 2 years each. When around 3% of their uranium is fissioned, they are sent to a spent fuel pool. After they spend about 5 years in the spent fuel pool, where the isotopes generated by fission can decay, and they are cool enough to handle, they can be reprocessed.

    Nuclear power plants provide about 5.7% of the worlds energy. They also provide 13% of the whole world’s electricity. With this in mind, it is important that we keep these running, for one nuclear power plant can provide a very large amount of power. It can be a very dangerous if the nuclear power plant overheats and has a meltdown, therefore, power plants need a variety of safety requirements. Safety feature of a nuclear power plant include high quality safety barriers and what is called an emergency core cooling system (ECCS). The ECCS is designed to remove large amounts of excess heat from the core to prevent damage to the reactor and the public. They also have sensors that automatically shut down the plant if an earthquake is underway. This is a necessity in many plants depending on where they are located. These reactors also have several passive safety features as well. These include pressure release valves which relieve the reactor of excess pressure build up. These reactors are also usually built near large bodies of water for cooling issues. This means that, when building a reactor, it is important to take into account certain exponents such as climate change which could cause flooding. For these reasons, reactors are built on platforms that are high enough to protect it during a natural disaster. Radiolytic decomposition of water forms hydrogen which needs to be dealt with, otherwise there is potential for an explosion. Newer reactors have been equipped with autocatalytic hydrogen combiners to prevent environmental disasters such as a radiation leak from the containment building.

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 Nuclear Debate Reflection

       In this debate about nuclear power, I took the position that nuclear power needed to end. This was the opposite of my true opinions. It was nice fighting for the other side so I could get a better look at the arguments, but in the end, I still agree with the continuation of nuclear energy. In the process of this debate, I learned a lot more about waste and the use of natural resources such as water have huge effects on our environment. The most persuasive argument that I had found when arguing for my side was the cost of nuclear power. The cost to build these facilities is insane and I can't see why any private company would ever buy into it. I also found that  the amount of uranium that we have at our disposal would last a very short amount of time compared to the money that would need to be spent on these facilities. Although it was good to find these facts, it was still very difficult to fight for the other side during the actual debate. I found it much harder to combat what the other team was saying when I fully agreed with them on most accounts.

    I see how nuclear energy can be bad for our environment but it is still better than the sources of energy, such as coal, that we use as a primary source currently. The main problem that I have with combating nuclear energy is what we would do in place of it. We need a cleaner source of energy other than coal and nuclear power is the next best thing. In relation to the humanities project, I have found that nuclear power would be better in saving the places I love. It's less destructive over all and is a step in the right direction to a cleaner planet.

    In the debate, I thought I did pretty well. I butchered my opening statement which I wish I could redo. I was nervous being the first one to speak and couldn't keep my thoughts in line, especially while trying not to look at my notes. I spoke against the opposition as well as I could have, leaving them stumbling for retaliations on a few of the arguments. I would not change anything about the arguments I used because I thought they were fairly solid. I would instead, if I could go back, use my time in perfecting my opening and closing statements, adding more human qualities to them and contributing more emotion.

The video to the debate can be found Here.

 The humanities portion of the project can be found Here.

My opening statement made in nuclear power debate:

    A little over two years ago the Fukushima Daiichi plant in Japan was hit by a tsunami that was formed by a massive earthquake. 538,100 terabecquerels of radioactive substances such as iodine-131, caesium-134, and caesium-137 were released into the atmosphere and the ocean surrounding the area effecting health issues such as cancer risk for those who are exposed. Nuclear energy is indeed an effective source of energy, though it’s dangers, along with its cost, both economical and medical, make it source that is unworthy of our time. It is very important for us to find a way to clean up our environment, though, doing this through nuclear power is not the right choice. The amount of greenhouse gasses and other environmental effects seems very miniscule on the surface, and even though the reactor itself does not directly affect the environment like burning coal, it does so indirectly. The process of uranium mining, milling, construction of the plant, operation, and the decommissioning of the plant. With this being said, the construction new nuclear plants and decommissioning of coal plants will cannibalize the existing energy that has already been produced. The nuclear plant uses only slightly more water than the more traditional ways of energy production, but the process of mining uranium also uses a very substantial amount of water. For example, the Roxy Downs uranium mine in Australia uses around 150 million litres of water in a single day.

Points addressed in closing statement:

-Nuclear power is not the way of the future

-The difference is not enough to offset the effects of global warming

-Even if it was effective, the majority of US companies would never buy into it

- we don’t know what to do with the waste

- and it uses a tremendous amount of water compared to traditional power sources

- all of this is huge but not compared to the possible health risks that these plants will entail on it’s workers and future generations.

-The construction of more plants will only increase these risks

- It is definitely time to start seeking different sources of cleaner energy.