Question Number 1 - Harrison Quick
How does nuclear fission work?
Nuclear fission is the act of a nucleus splitting, and defined, in basic terms, as the release of energy from the loss of mass of the atom in its entirety. While unstable atoms release energy constantly, the greatest amount of energy may be observed when the nucleus of an atom splits.
The greater the atomic weight of an atom, the greater the amount of energy is going to be released. For example, an atom like a Uranium-235 atom, when splitting, releases huge amounts of energy, given Einstein’s equation (energy = mass * the speed of light2). This equation is applicable, because when the Uranium-235 atom’s nucleus splits via fission, the weight of the combined particles of what was the nucleus is less than the weight of the atom before splitting. The mass is, thereby, converted to energy.
To trigger the fission of uranium-235, a “slow neutron” is introduced to the atom of uranium, rendering the atom unstable. In its instability, the uranium atom is split, beginning the chain reaction. The probability of a neutron being “caught” by a uranium-235 atom is greater when the neutron is slowed down. Fast neutrons have a lesser probability of being caught by a uranium-235 atom. Slowing down a neutron is done through something called “moderation”, which takes place in a fission reactor.
Moderation is done with the use of water, which also works as a coolant in nuclear fission. The neutrons that are emitted when a uranium atom undergoes fission travel through water between uranium rods in the core, slowing them down, and heightening the probability of each neutron being “caught” by a uranium atom.
So, as a recap, when a neutron is released, and caught by a uranium-235 atom, the atom becomes unstable, and the nucleus splits, losing mass, and releasing both energy and neutrons. The neutrons spread out, and are slowed down with the use of water, making them more easily “caught” by another uranium-235 atom, again rendering it unstable, and the process begins again. This is a chain reaction.
Question Number 2 - Josiaph Jenkins
E=mc2
·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.
Nuclear reaction deals with interactions between the nuclei of atoms being mass and energy. Both mass and energy can not be created and neither destroyed. They are two forms of the same thing, as equals, meaning mass can be converted into energy and vice versa. Einstein’s formula E=mc2 shows us how this change occurs. Also, E is energy, m is mass, and c squared is the speed of light in a vacuum being a universal constant. Light travels at the speed of 186,000 miles per second or 300,000 kilometers per second.
Nuclear power comes from splitting uranium atoms in a process called fission. At a power plant, the fission process is used to generate heat for producing steam, which is used by a turbine to generate electricity. More on fission, when it splits an atomic nucleus into fragments being the form of a smaller atomic nucleus and neutrons. Big sums of energy are made by this process since the mass of the product is less than the mass of the reactants. Thus making it understandable on how much energy is used through nuclear fission by Einstein’s equation E=mc2. By using a small amount of mass can produce large amounts of energy since the speed of light is a big number in the equation.
During the nuclear fission process of uranium 235 there is a percent loss of mass being 7.91*10^-4, because not all mass can be converted into energy.
A good example of this formula is by taking the mass being 0.3 kg of uranium and multiplying it by the speed of light being (3*10^8 miles per second)^2 equals 2.7 times 10 to the sixteenth power joules or the energy that has been produced. Lastly, multiply the product by this percent conversion of 7.91*10^-4 since not all mass is converted into energy. In the end the example equation looks like this: 0.3 kg *(3*10^8 m/s)^2 = 2.7*10^16 ---> 2.7*10^16 * 7.91*10^-4= 2.13*10^13 joules. This means that only 0.3 kilograms of uranium 235 used can power a sixty second kilowatt light bulb for approximately 11,286 years.
Bibliography
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Question Number 3 - Bella Kidd
How are radioactive materials for nuclear power plants milled, mined and enriched?
The mining of radioactive materials is a huge industry worldwide. While uranium, for example, is mined worldwide, some of the producers are in low-income countries such as China, Niger, Namibia, Uzbekistan, Russia and Ukraine. Many techniques are available in order to mine radioactive materials, such as open pit, underground uranium mining, and heap leaching.
Open Pit: In open pit mining, overburden (waste or spoil) is removed by drilling and blasting to expose the ore body, which is then mined by blasting and excavation using loaders and dump trucks. In order to limit exposure to radiation, workers spend lots of time in enclosed cabins. Water is greatly used to suppress and control airborne dust from this tactic of mining.
Underground Uranium Mining: If the uranium is too far below the surface for open pit mining, an underground mine can be used with tunnels and shafts to access and remove the ore. Underground uranium mining is very similar to other rock mining and other ores. Once the ore body has been identified a shaft is put into the ore veins, and crosscuts are driven horizontally to the veins at various levels, usually every 100 to 150 meters. Similar drifts, or tunnels, are driven along the ore veins from the crosscut. To extract the ore, the next step is to drive tunnels (known as raises when driven upwards and winzes when driven downwards) through the deposit from level to level. These raises are used to develop stopes where the uranium is mined. Either the cut-and-fill method is used (the leftover space in the ground after ore after blasting is filled with waste rock and cement), or shrinkage (broken ore is removed to allow miners working at the top of the pile to drill and blast the next layer to be fragmented off).
Heap Leaching: In this method, chemicals (usually sulfuric acid) are used to extract the element from ore which has already been mined and piled on the surface. Oxidation of the sulfide deposits occurs in weathering. These deposits are usually found close to the surface. The extracted ore is run through a crusher and it is placed in heaps on top of a thick plastic that lays in a large area of land. A leaching agent, or the acid, is sprayed on the ore for 30-90 days, then as acid filters through the heap, the uranium breaks its bonds with the oxide rock and the resulting solution is filtered into collecting pools which are pumped on-site to plants for further processing.
In-Situ Leaching: This method of mining involves leaving the ore where it is in the ground and recovering the minerals from it by dissolving them and driving the solution to the surface where the minerals are collected. There is little surface disturbance and no tailings or waste rock generated with this method. However, the orebody needs to be penetrable to the liquids used, and located so that they do not contaminate ground water apart from the orebody.
Question Number 4 –Riley Wanzek
Describe the design of a light water nuclear power plant.
Nuclear power has a multi step process in order to produce the energy we all value so much. The process of this energy production starts with many small, enriched, thumbnail sized pellets of Uranium also known as fuel rods. These pellets are held in control rods, a device that can forecast the amount of radioactive decay developed from the Uranium pellets. With many different amounts of power produced this device is put to use quite a bit. Similarly this device can cut any radioactive decay also acting as a safety feature, one needed with this type of hazardous material. The containment structure holds all of the radioactive ingredients needed to produce the power, also consisting of primary coolant. With the high temperatures produced by the nuclear reaction the cooling process is vital. The primary coolant is held within the contentment structure and this is the first line of defense against the high temperatures produced the refined area. The containment structure is a pressurized cabin, aiding the coolant by keeping it in liquid form.
The high temperatures in the containment structure transfer to the secondary coolant through a heat exchanger. As the heat is exchanged the coolant reaches the state of steam and forces its way through a turbine setting the energy production into gear. This production of energy is then fed into the electric grid for the use of the people. Now that the energy has been produced the process isn’t over, many steps of cooling and condensing follow. After the steam is condensed the tertiary coolant is cycled through cooling towers. Water falling the hot water down the towers airing out the molecules as much as possible, serving as the final step in the cooling process. Finally the coolant condenses from steam back into water, ready to be cycled back through the process.
This measure of energy production needs to ensure many safety requirements and devices in order to preform quality and safe energy. Advancements such as self-orchestrating control rods reduce the amount of human interaction. Refinements like gravity-aided tanks have been developed, supplying the primary coolant with enough coolant at all times after loss of coolant due to condensation.
Work cited
"Nuclear Power." Wikipedia. Wikimedia Foundation, 30 Apr. 2014. Web. 29 Apr. 2014.
Brain, Marshall, and Robert Lamb. "How Nuclear Power Works."HowStuffWorks. HowStuffWorks.com, 09 Oct. 2000. Web. 26 Apr. 2014.
"Energy.gov." Office of Nuclear Energy. N.p., n.d. Web. 27 Apr. 2014.
Question Number 5 –Harrison Quick
Describe the operating processes of a light water nuclear power plant
A nuclear power plant runs on steam produced with the use of uranium-235 atoms. Uranium-235 itself is the only fissile (can undergo nuclear fission; see above) isotope that is found in nature in usable quantities, and has a primordial nuclide. To have a primordial nuclide means that the atom that is being specified has existed in that form since before the earth was born.
In the year 2012, in the United States, it was found that on average, each nuclear power plant produced about 11,800,000,000 kWh (kilowatt-hours). Multiply that by the 65 plants in the United states, and we find that in 2012, nuclear power supplied about 19% of the US’s electricity, or, 769,000,000,000 kWh (EIA, U.S.). The average household consumes about 10,837 kWh annually (EIA, U.S.). The amount of energy provided by nuclear reactors, given this information, can provide for about 70,960,598 homes.
Fuel rods typically last about 6 years in a reactor, unless all of the uranium is used up sooner than 6 years (Laura, Conaway). In replacing the rods, they are still very, very hot, so they are placed into pools of water (40x45 ft), where the water circulates to maintain cooling effects, and the water provides an insulator from the radiation (. New rods are placed with electromagnetic machinery.
To control the output of power being generated from a nuclear reactor, less neutrons are used, and in order to do so, the neutrons are absorbed in the control rods, which are made of boron, silver, indium, and cadmium. The control rods are lowered and raised in order to allow for more or less energy production. When the control rods are lowered further, fewer neutrons are able to travel through, and less energy is generated. The opposite happens when the bars are heightened.
Safety measures include the use of machinery to prevent human error from influencing any further problems, regular and constant system monitoring and testing to determine any possible problems, and technology to prevent the fuel from doing any damage to the plant itself.
Nuclear power plants were determined to have a lifespan of about 40 years, but now the US fleet of nuclear power plants is predicted to last 50-70 years. Technically however, they don’t have age limits, because they are constantly changing parts of nuclear reactors even before any problems occur, to ensure they don’t.
Nuclear reactors in the US are typically around 33% efficient. This means that for every three units of thermal energy that are being generated with a nuclear reactor, while one unit of electricity may go out onto the grid, two units of heat are lost, and are released into the environment.
Works Cited:
"Primordial Nuclide." Wikipedia. Wikimedia Foundation, 15 Apr. 2014. Web. 25 Apr.
2014. <http://en.wikipedia.org/wiki/Primordial_nuclide>.
"Uranium-235." Wikipedia. Wikimedia Foundation, 22 Apr. 2014. Web. 25 Apr. 2014.
<http://en.wikipedia.org/wiki/Uranium-235>.
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Question Number 6
Breeze Maestas
How much radiation is the surrounding environment subjected to from a properly function nuclear power plant?
“An operating nuclear power plant produces very small amounts of radioactive gases and liquids, as well as small amounts of direct radiation. If you lived within 50 miles of a nuclear power plant, you would receive an average radiation dose of about 0.01 millirem per year. To put this in perspective, the average person in the United States receives an exposure of 300 millirem per year from natural background sources of radiation.” An average american is exposed to 620 millirems per year, we are exposed to all different types of radiation in our daily lives such as cell phones, the sun, xrays, etc. There is just as much to be feared in this area as there is with nuclear power plants. As Americans we are exposed to a steady stream of radiation in our everyday lives and the small added amount, due to exposure to nuclear power plants does not raise your levels to a dangerous high.
What risk for nuclear meltdown exists in light water reactors in the U.S.?
In the United States, there are 104 nuclear reactors. Some of these nuclear power plants have had emergency shut downs in the past, indicating the possibility of a more unexpected shut downs in the future. In May of 2011, five of the nuclear reactors were shut down due to emergencies. Severe weather such as hurricanes, tsunamis and tornadoes can affect the nuclear power plants. Along with natural disasters, these plants are also at risk through a few other instabilities including the type of reactor, either boiling water reactor or a pressurized water reactor; the age of the reactor; power level of the reactor. Researchers have found that the boiling water reactors are less able to prevent the release of radiation in the event of a natural disaster. Most nuclear power plants have a lifespan of 40 years. However, the Nuclear Regulatory Commission has declared that several nuclear power plants can operate for 60 years. As the plant gets older, so do the components, potentially making for a weaker, less secure plant. Lastly, the power production of a plant determines the level of wear and tear. In some cases, the reactors have been pushed past their limit to produce more energy than they are designed for, weakening all back-up systems. The United States also has organizations that aim to monitor and ensure all nuclear power plants are practicing the safest methods of energy production. Additionally, all power plants are closely monitored and improved emergency systems have been developed to increase safety. Through all of these safety procedures, there is still the slim chance that a natural disaster could occur and that unpredictable accident may lead to a meltdown or other damage to the plant.
What are potential risks to nuclear power plants from events like natural disaster and terrorist attacks?
There are always risks such as natural disasters and terrorist attacks. Natural disasters are more possible and a greater risk to the common public than terrorist attacks. Terrorist attacks are not extremely probable or thought to be very problematic. The reason for that explanation is, the only thing that could be of any harm is if, an object (i.e. a plane or missile) crashed into the nuclear plant site, then hit the core of the reactor. The probability of that happening is very low. Natural disasters are more of a problem because they cause more damage and are stronger as well as less predictable.
What safety features are being built in light water reactors in the U.S.?
There are a few ideas being proposed about making the light water reactors safer as well as safer. One idea is looking into advanced pumps, heating and cooling systems and turbines. Another plan that is being implemented in the United States mandates that the reactor be built with “32 per cent fewer valves, 35 per cent fewer pumps, and 45 per cent less pipe than a traditional power.”
How much radioactive waste is produced by a typical light water reactor?
“Thermal-neutron reactors are the most common type of reactor, and light water reactors are the most common type of thermal-neutron reactor. In the OECD countries, some 300 million tons of toxic wastes are produced each year, but conditioned radioactive wastes amount to only 81,000 m3 per year. A typical 1000 MWe light water reactor will generate (directly and indirectly) 200-350 m3 low- and intermediate-level waste per year.”
Question Number 7
Breeze Maestas
What radionuclides are typically in radioactive waste and in what concentrations?
‘There are six levels of radioactive wastes:
1. exempt waste
2. very short lived waste
3. very low level waste
4. low level waste
5. intermediate waste
6. high level waste’
what are the half lives of the radionuclides found in radioactive waste and in what concentrations?
“Plutonium has at least 15 different isotopes, all of which are radioactive. The most common ones are Pu-238, Pu-239, and Pu-240. Pu-238 has a half-life of 87.7 years. Plutonium-239 has a half-life of 24,100, and Pu-240 has a half-life 6,560 years. The isotope Pu-238 gives off useable heat, because of its radioactivity. Iodine is also commonly found in radioactive substances. Plutonium has at least 15 different isotopes, all of which are radioactive. The most common ones are Pu-238, Pu-239, and Pu-240. Pu-238 has a half-life of 87.7 years. Plutonium-239 has a half-life of 24,100, and Pu-240 has a half-life 6,560 years. The isotope Pu-238 gives off useable heat, because of its radioactivity.”
What are the types of decay the radionuclides in radioactive waste undergo? WHat are their decay energies?
“Most naturally occurring radioactive materials and many fission products; undergo radioactive decay through a series of transformations (loss of particles or electromagnetic energy from an unstable nucleus) rather than in a single step. Until the last step, these radionuclides emit energy or particle with each transformation and become another radionuclide. Man-made elements, which are all heavier than uranium and unstable, undergo decay in this way. This decay chain, or decay series, ends in a stable nuclide.”
Work Cited
"Categorisation of Radioactive Waste." European Nuclear Safety Regulators Group. European Nuclear Safety Regulators Group, n.d. Web. 27 Apr. 2014.
"Decay Chains." EPA. Environmental Protection Agency, n.d. Web. 27 Apr. 2014.
"Frequently Asked Questions (FAQ) About Radiation Protection." NRC:. United States Nuclear Regulatory Committee, 11 Dec. 2012. Web. 27 Apr. 2014.
"Iodine." EPA. United States Environmental Protection Agency, n.d. Web.
"Plutonium." EPA. Environmental Protection Agency, n.d. Web. 27 Apr. 2014.
"Nuclear reactor safety systems."Wikipedia.N.p.: Wikimedia Foundation, 2014. Wikipedia.Web. 27 Apr. 2014.
"Backgrounder on Radioactive Waste." NRC:.N.p., n.d. Web. 27 Apr. 2014
Question Number 8 –Josh Davoust
What are emissions from nuclear power plants?
How have the emissions from nuclear power plants affected local air quality as compared to other forms of energy production?
Nuclear power produces very few emissions. The only direct emission from a nuclear power plant is depleted fuel rods that require special disposal. With consideration to the entire life of a nuclear power plant there are still less emissions than other power sources. Although no green house gasses (GHG) are directly emitted by nuclear power production the extraction and disposal of uranium account for some GHG. Regardless, nuclear power still produces far less GHG than any other nonrenewable energy source. World Nuclear Association reported that the tonnes of CO2 emitted per GWh by nuclear(29) is lower than all energy sources apart from hydro(26) and geothermal(26); natural gas emitted 888 t/GWh and 499 t/GWh from natural gas (this study used the life time emission). For surrounding areas a very minimal amount of radiation is emitted, however more radiation is released by a coal plant and this amount is a fraction of a percent of the radiation we are exposed to. The largest emission concern for nuclear power is the radioactive material. The waste is stored until it is no longer hazardous, this can be indefinitely.
Works Cited
"Life Cycle Assessment Harmonization Results and Findings." NREL: Energy Analysis -. N.p., n.d. Web. 30 Apr. 2014. <http://www.nrel.gov/analysis/sustain_lca_results.html>.
"Life-Cycle Emissions Analyses." Nuclear Energy Institute -. N.p., n.d. Web. 27 Apr. 2014.
"Nuclear Helps Exelon Achieve Emissions Goal." Lifecycle GHG Emissions of Electricity Generation Sources. N.p., n.d. Web. 30 Apr. 2014. <http://www.world-nuclear.org/WNA/Publications/WNA-Reports/Lifecycle-GHG-Emissions-of-Electricity-Generation/>.
Question Number 9 –Josh Davoust
What are environmental and safety considerations for the storage of nuclear waste?
When the life of nuclear fuel cells is depleted they become nuclear waste. Radioactive waste can also be considered anything that has been irradiated. Nuclear Waste poses challenges because it waste is harmful to most life and is not easily discarded. Once the fuel rods are no longer in use at the power plant they must be cooled and stored. Depleted rods still emit very large amounts of radiation and living organisms cannot be exposed to them. The spent rods emit alpha, beta, and gamma radiation. Measures are required to prevent this radiation from irritating anything. Waste is categorized as low-level, intermediate-level, and high-level radioactive waste based on the amount of time until it will no longer be hazardous.
Low and intermediate-level waste does not need to be store as securely or for as long. Most countries including the US have facilities to store low and intermediate waste. High level waste is waste that must be stored for incredibly long amounts of time, between thousands to billions of years. No country currently operates a high level civilian nuclear waste facility, a facility for power plant waste. Currently waste is stored in temporary containment locations.
High level waste facilities have not been opened due to the effort required to complete such a facility. The facility would have to withstand the most strenuous conditions such as natural disasters. Currently the most viable option is deep earth burial. Deep burial would prevent any radiation from reaching the surface and harming life on earth. If containment of waste were to leak it would cause irreparable damage to the ecosystem. Leaked radiation mutates DNA and would force areas to become inhabitable. Because of the time it would take before the waste is no longer a threat storage facilities would have to be completely inaccessible forever.
Works Cited
Findlay, Trevor. THE FUTURE OF NUCLEAR ENERGY TO 2030 AND ITS IMPLICATIONS FOR SAFETY, SECURITY AND NONPROLIFERATION. Issue brief. N.p.: Cigionline, n.d. Print.
"National Policies." : Radioactive Waste Management. N.p., n.d. Web. 30 Apr. 2014. <http://www.world-nuclear.org/info/nuclear-fuel-cycle/nuclear-wastes/appendices/radioactive-waste-management-appendix-3--national-policies/>.
"NDA Attacked over Magnox Contract." Radioactive Waste Management. N.p., n.d. Web. 30 Apr. 2014. <http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Nuclear-Wastes/Radioactive-Waste-Management/>.
"Storage of Spent Nuclear Fuel." NRC:. N.p., n.d. Web. 29 Apr. 2014. <http://www.nrc.gov/waste/spent-fuel-storage.html>.
Question Number 10 –Riley Wanzak
Describe the science involved in global climate change and how it relates to emissions from nuclear power pants and fossil fuel power plants.
As we use energy in the form or transportation, production and consumption we produce a gas, which is regularly occurring, but not at the rate it is now. It all involves the greenhouse effect, a vital and delicate system for life on Earth.
As we receive light from the sun it is either reflected back to space of absorbed into the environment. The environment then releases this energy as infrared radiation, some of this radiation is again released some of it is contained to warm the Earth. But as this delicate filter that releases the infrared radiation becomes bombarded with more carbon dioxide more of the heat is contained, ultimately warming the atmosphere. If still confused think of the atmosphere as a shirt around the Earth. This shirt is breathable and moderates a temperature perfect for our comfort. But now the shirt becomes clogged and contains more heat then suitable for element such as ice caps.
Over time as man has the increases need for energy, the increase has also been found in the gases emitted into the atmosphere. Due to the warming of the environment vital elements of nature are becoming scarce, mainly elements involving a cooler climate conditions. Ice caps are receding into the ocean; Shorter and shorter winters have been recorded. These are the effects of climate change and they will only get worse in the future.
Cleaner efforts have been achieved to reduce this carbon footprint. The production of nuclear power shows the use in a highly efficient process. With mining and transportation emissions still present this method does still produce emissions but little at the tail pipe of the nuclear reactor. Posing a much more efficient production than coal or natural gas which both emit greenhouse gases after the combustion of the substance.
Work Cited
"The Greenhouse Effect." EPA. Environmental Protection Agency, 9 Aug. 2013. Web. 28 Apr. 2014.
"Greenhouse Effect." Wikipedia. Wikimedia Foundation, 30 Apr. 2014. Web. 29 Apr. 2014.
Question Number 11 –Bella Kidd
What are the environmental and safety issues associated with the mining and refining of nuclear fuel?
Health risks that come at the cost of nuclear power production are plentiful. Cases of water contamination with radioactive substances has occurred around over a dozen different nuclear sites around just the United States alone. The process of mining materials used in nuclear power plants such as uranium and titanium run a very high risk of water contamination to near by rivers and streams as well as ground water supplies. In addition to water contamination, exposure to radioactive material can sometimes be deadly, causing health problems and cancer. Through the history of nuclear disasters, it has been observed that there has been a definite negative effect on human health caused by nuclear power plants along with infertility, health problems, and deadly cancers among people in communities even far away from original nuclear site.
Where is uranium mined and approximately how much is available in the US? In the world?
The three largest producers of uranium are Kazakhstan, Canada and Australia. These countries account for 63% of worldwide uranium production. Only about 3% is mined here in the United States, however.
Annually, about 50,500 metric tons of uranium are produced worldwide (Uranium)(2009) . Given this statistic, the United States mines roughly 1,515 metric tons of uranium annually.
(Image source: Wikipedia)
How much of our energy needs can uranium provide?
Uranium is a heavy metal that can be used as an abundant source of concentrated energy. A very small amount of uranium can be converted into a very large amount of energy. Uranium provides about 12% of the world’s electricity which is generated in nuclear reactors. This amounts to more than 2500 kWh (kilowatts) each year. This basic electricity is provided to people worldwide to power homes, businesses, and more.
Aside from providing basic electricity, uranium can be used as a military source of fuel. Bomb-grade uranium is highly enriched compared to uranium for domestic power use(up to 90% U-235 instead of up to 5%). Uranium is ideal for nuclear bombs because of a process that it undergoes called nuclear fission, which occurs when a neutron and a target nucleus collide. A powerful chain reaction is created and a significant amount of energy is created as a result.
Not only is uranium used in just energy form; it can be used in physical form as well. Uranium can also be used as an additive for glass and ceramics, a toner in photography, or as an additive for the preparation of biological samples for electrons and other minor applications.
What are the best estimates for the purely financial cost of nuclear power generated electricity?
In the production of nuclear energy, total cost is based upon the costs associated with the purchasing of uranium, conversion, enrichment, and fabrication services along with storage and shipment costs, and any inventory charges.
For a typical BWR (boiling water reactor) or PWR (pressurized water reactor), the approximate cost of fuel for one reload (replaces one third of the core) is roughly $40 million, based on a 18-month typical refueling cycle. In 2012, the average fuel cost at a nuclear power plant was 0.75 cents per kWh. Since nuclear plants are refueled every 18-24 months, fluctuating fuel prices are not a concern compared to natural gas and oil power plants.
Included in the price of nuclear power are the costs related to waste management. About $35.8 billion (or 1/10th of a cent per kWh of electricity generated at nuclear power plants since 1983 with interest) is devoted to funds committed for the Nuclear Waste Fund. Per each nuclear power plant, about $300 million to $500 million covers the cost of estimated used fuel ($100 million) and site restoration (about $300 million).
What are the levelized costs per kWh?
Levelized energy cost (LEC, also known as Levelized Cost of Energy, abbreviated LCOE) is the price at which electricity must be generated from a specific source to in order to break even over the lifetime of the project. This economic assessment includes all costs of running a nuclear power plant such as initial investment, maintenance, fuel cost, and more. In 2012, the estimated total system levelized cost of advanced nuclear plants was 96.1 USD/mWh (megawatts) (Costs).
What are fuel costs annually or per kWh? Construction costs for a new plant? Operating and maintenance costs?
As mentioned previously, the average cost of fuel at a nuclear power plant was 0.75 cents/kWh. Annually, the levelized cost of advanced nuclear plants was 96.1 USD/mWh in total.
The construction cost estimates for new nuclear power plants vary greatly and have increased significantly in recent years. Total costs of a new nuclear plant are estimated to be within the range of $5,500/kWh to $8,100/kWh. This translates to a cost between $6 billion and $9 billion for each 1,100 MW plant established. Just in the years from 2000-2002, the costs for new nuclear units were between $1,200/kWh and $1,500/kWh.
The average non-fuel operation and maintenance cost for a nuclear power plant in 2012 was reported to be 1.65 cents/kWh.
Works Cited
"7 Reasons Why Nuclear Power Is Bad for the Environment and the Nation." Examiner.com. N.p., n.d. Web. 27 Apr. 2014.
"Costs: Fuel, Operation, Waste Disposal & Life Cycle." Nuclear Energy Institute -. N.p., n.d. Web. 28 Apr. 2014.
"Radioactive Waste and Uranium Mines." :: WorstPolluted.org : Projects Reports. N.p., n.d. Web. 24 Apr. 2014.
"The University of Michigan Health Physics Web Site: Risks of Nuclear Power." The University of Michigan Health Physics Web Site: Risks of Nuclear Power. N.p., n.d. Web. 26 Apr. 2014.
"Uranium Mining." Wikipedia. Wikimedia Foundation, Apr. 2014. Web. 27 Apr. 2014.
"What Is Uranium? How Does It Work?" What Is Uranium? How Does It Work. N.p., n.d. Web. 29 Apr. 2014.
Question Number 12 - Reuben Barnes
Science Involved in Global Climate Change/Relation to Emissions of Nuclear Power Plants
Reuben Barnes
· What is the greenhouse effect and how is it related to global climate change?
o The greenhouse effect is when gasses that can absorb the energy that is released from the sun and back out from the earth. When the sun’s rays penetrate the Earth they are absorbed by the ground, then this energy is released back out. Now some of that energy goes back in space but the rest of it is captured by greenhouse gasses that are in the atmosphere. (They collect this heat energy and hold it in the atmosphere, delaying its passage back out of the atmosphere.)These gasses are the only things that can capture the infrared rays that are released from the sun. This is necessary for our planet but at the same time if there is an excessive amount of gasses to capture heat then it will negatively affect the planet. The greenhouse effect is necessary because those gasses that are trapped inside keep the Earth warm, without it the temperature would decrease to an unlivable point; the earth would be so cold that we would freeze to death. However if there are too many gasses that are trapped in the atmosphere then it can cause a huge increase in heat, this is because when there are extra greenhouse gasses in the air they capture an excessive amount which can result with a unusual release of heat. The increase in heat is caused by all the carbon dioxide that is released into the air, with all of the machinery that requires gasoline or fossil fuels all emit a large amount of carbon dioxide. So due to all of the emissions the global climate is heated up and then unbalanced. This climate change can affect a lot of things that are on the planet, for example (Rising temperature also means melting glaciers and rising sea level through addition of melt water to the oceans. Sea level rose about 1 foot during the last century, mostly from thermal expansion of the oceans.). This increase in temperature will clearly affect us in the end which will damage our society and can be very deadly.
o
· What are greenhouse gases and what about their structure makes them greenhouse gases?
o Greenhouse gasses are certain gasses that are in the atmosphere, these gasses are water vapor, carbon dioxide, methane ozone, and nitrous oxide. Each of these absorbs the infrared radiation that is emitted from the sun. Once they have captured some of that energy they can slowly release it back into the atmosphere which then creates heat. Each one of these specific gasses are bonded by two or more molecules, now each one of these bonds are loose, so when they absorb the energy they will vibrate and can release the heat again. All other types of gasses have to tight bonds and therefore do not contribute to the greenhouse effect.
o
Sites:
· "The Greenhouse Effect." Greenhouse Effect: Background Material. N.p., n.d. Web. 29 Apr. 2014.
· "The Greenhouse Effect." The Greenhouse Effect. N.p., n.d. Web. 30 Apr. 2014.
· http://www.columbia.edu/~vjd1/greenhouse.gif
· http://www.ucar.edu/learn/images/radiate.gif
Science Involved in Global Climate Change/Relation to Emissions of Nuclear Power Plants
How does nuclear fission work?
Nuclear fission is the act of a nucleus splitting, and defined, in basic terms, as the release of energy from the loss of mass of the atom in its entirety. While unstable atoms release energy constantly, the greatest amount of energy may be observed when the nucleus of an atom splits.
The greater the atomic weight of an atom, the greater the amount of energy is going to be released. For example, an atom like a Uranium-235 atom, when splitting, releases huge amounts of energy, given Einstein’s equation (energy = mass * the speed of light2). This equation is applicable, because when the Uranium-235 atom’s nucleus splits via fission, the weight of the combined particles of what was the nucleus is less than the weight of the atom before splitting. The mass is, thereby, converted to energy.
To trigger the fission of uranium-235, a “slow neutron” is introduced to the atom of uranium, rendering the atom unstable. In its instability, the uranium atom is split, beginning the chain reaction. The probability of a neutron being “caught” by a uranium-235 atom is greater when the neutron is slowed down. Fast neutrons have a lesser probability of being caught by a uranium-235 atom. Slowing down a neutron is done through something called “moderation”, which takes place in a fission reactor.
Moderation is done with the use of water, which also works as a coolant in nuclear fission. The neutrons that are emitted when a uranium atom undergoes fission travel through water between uranium rods in the core, slowing them down, and heightening the probability of each neutron being “caught” by a uranium atom.
So, as a recap, when a neutron is released, and caught by a uranium-235 atom, the atom becomes unstable, and the nucleus splits, losing mass, and releasing both energy and neutrons. The neutrons spread out, and are slowed down with the use of water, making them more easily “caught” by another uranium-235 atom, again rendering it unstable, and the process begins again. This is a chain reaction.
Question Number 2 - Josiaph Jenkins
E=mc2
·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.
Nuclear reaction deals with interactions between the nuclei of atoms being mass and energy. Both mass and energy can not be created and neither destroyed. They are two forms of the same thing, as equals, meaning mass can be converted into energy and vice versa. Einstein’s formula E=mc2 shows us how this change occurs. Also, E is energy, m is mass, and c squared is the speed of light in a vacuum being a universal constant. Light travels at the speed of 186,000 miles per second or 300,000 kilometers per second.
Nuclear power comes from splitting uranium atoms in a process called fission. At a power plant, the fission process is used to generate heat for producing steam, which is used by a turbine to generate electricity. More on fission, when it splits an atomic nucleus into fragments being the form of a smaller atomic nucleus and neutrons. Big sums of energy are made by this process since the mass of the product is less than the mass of the reactants. Thus making it understandable on how much energy is used through nuclear fission by Einstein’s equation E=mc2. By using a small amount of mass can produce large amounts of energy since the speed of light is a big number in the equation.
During the nuclear fission process of uranium 235 there is a percent loss of mass being 7.91*10^-4, because not all mass can be converted into energy.
A good example of this formula is by taking the mass being 0.3 kg of uranium and multiplying it by the speed of light being (3*10^8 miles per second)^2 equals 2.7 times 10 to the sixteenth power joules or the energy that has been produced. Lastly, multiply the product by this percent conversion of 7.91*10^-4 since not all mass is converted into energy. In the end the example equation looks like this: 0.3 kg *(3*10^8 m/s)^2 = 2.7*10^16 ---> 2.7*10^16 * 7.91*10^-4= 2.13*10^13 joules. This means that only 0.3 kilograms of uranium 235 used can power a sixty second kilowatt light bulb for approximately 11,286 years.
Bibliography
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Question Number 3 - Bella Kidd
How are radioactive materials for nuclear power plants milled, mined and enriched?
The mining of radioactive materials is a huge industry worldwide. While uranium, for example, is mined worldwide, some of the producers are in low-income countries such as China, Niger, Namibia, Uzbekistan, Russia and Ukraine. Many techniques are available in order to mine radioactive materials, such as open pit, underground uranium mining, and heap leaching.
Open Pit: In open pit mining, overburden (waste or spoil) is removed by drilling and blasting to expose the ore body, which is then mined by blasting and excavation using loaders and dump trucks. In order to limit exposure to radiation, workers spend lots of time in enclosed cabins. Water is greatly used to suppress and control airborne dust from this tactic of mining.
Underground Uranium Mining: If the uranium is too far below the surface for open pit mining, an underground mine can be used with tunnels and shafts to access and remove the ore. Underground uranium mining is very similar to other rock mining and other ores. Once the ore body has been identified a shaft is put into the ore veins, and crosscuts are driven horizontally to the veins at various levels, usually every 100 to 150 meters. Similar drifts, or tunnels, are driven along the ore veins from the crosscut. To extract the ore, the next step is to drive tunnels (known as raises when driven upwards and winzes when driven downwards) through the deposit from level to level. These raises are used to develop stopes where the uranium is mined. Either the cut-and-fill method is used (the leftover space in the ground after ore after blasting is filled with waste rock and cement), or shrinkage (broken ore is removed to allow miners working at the top of the pile to drill and blast the next layer to be fragmented off).
Heap Leaching: In this method, chemicals (usually sulfuric acid) are used to extract the element from ore which has already been mined and piled on the surface. Oxidation of the sulfide deposits occurs in weathering. These deposits are usually found close to the surface. The extracted ore is run through a crusher and it is placed in heaps on top of a thick plastic that lays in a large area of land. A leaching agent, or the acid, is sprayed on the ore for 30-90 days, then as acid filters through the heap, the uranium breaks its bonds with the oxide rock and the resulting solution is filtered into collecting pools which are pumped on-site to plants for further processing.
In-Situ Leaching: This method of mining involves leaving the ore where it is in the ground and recovering the minerals from it by dissolving them and driving the solution to the surface where the minerals are collected. There is little surface disturbance and no tailings or waste rock generated with this method. However, the orebody needs to be penetrable to the liquids used, and located so that they do not contaminate ground water apart from the orebody.
Question Number 4 –Riley Wanzek
Describe the design of a light water nuclear power plant.
Nuclear power has a multi step process in order to produce the energy we all value so much. The process of this energy production starts with many small, enriched, thumbnail sized pellets of Uranium also known as fuel rods. These pellets are held in control rods, a device that can forecast the amount of radioactive decay developed from the Uranium pellets. With many different amounts of power produced this device is put to use quite a bit. Similarly this device can cut any radioactive decay also acting as a safety feature, one needed with this type of hazardous material. The containment structure holds all of the radioactive ingredients needed to produce the power, also consisting of primary coolant. With the high temperatures produced by the nuclear reaction the cooling process is vital. The primary coolant is held within the contentment structure and this is the first line of defense against the high temperatures produced the refined area. The containment structure is a pressurized cabin, aiding the coolant by keeping it in liquid form.
The high temperatures in the containment structure transfer to the secondary coolant through a heat exchanger. As the heat is exchanged the coolant reaches the state of steam and forces its way through a turbine setting the energy production into gear. This production of energy is then fed into the electric grid for the use of the people. Now that the energy has been produced the process isn’t over, many steps of cooling and condensing follow. After the steam is condensed the tertiary coolant is cycled through cooling towers. Water falling the hot water down the towers airing out the molecules as much as possible, serving as the final step in the cooling process. Finally the coolant condenses from steam back into water, ready to be cycled back through the process.
This measure of energy production needs to ensure many safety requirements and devices in order to preform quality and safe energy. Advancements such as self-orchestrating control rods reduce the amount of human interaction. Refinements like gravity-aided tanks have been developed, supplying the primary coolant with enough coolant at all times after loss of coolant due to condensation.
Work cited
"Nuclear Power." Wikipedia. Wikimedia Foundation, 30 Apr. 2014. Web. 29 Apr. 2014.
Brain, Marshall, and Robert Lamb. "How Nuclear Power Works."HowStuffWorks. HowStuffWorks.com, 09 Oct. 2000. Web. 26 Apr. 2014.
"Energy.gov." Office of Nuclear Energy. N.p., n.d. Web. 27 Apr. 2014.
Question Number 5 –Harrison Quick
Describe the operating processes of a light water nuclear power plant
A nuclear power plant runs on steam produced with the use of uranium-235 atoms. Uranium-235 itself is the only fissile (can undergo nuclear fission; see above) isotope that is found in nature in usable quantities, and has a primordial nuclide. To have a primordial nuclide means that the atom that is being specified has existed in that form since before the earth was born.
In the year 2012, in the United States, it was found that on average, each nuclear power plant produced about 11,800,000,000 kWh (kilowatt-hours). Multiply that by the 65 plants in the United states, and we find that in 2012, nuclear power supplied about 19% of the US’s electricity, or, 769,000,000,000 kWh (EIA, U.S.). The average household consumes about 10,837 kWh annually (EIA, U.S.). The amount of energy provided by nuclear reactors, given this information, can provide for about 70,960,598 homes.
Fuel rods typically last about 6 years in a reactor, unless all of the uranium is used up sooner than 6 years (Laura, Conaway). In replacing the rods, they are still very, very hot, so they are placed into pools of water (40x45 ft), where the water circulates to maintain cooling effects, and the water provides an insulator from the radiation (. New rods are placed with electromagnetic machinery.
To control the output of power being generated from a nuclear reactor, less neutrons are used, and in order to do so, the neutrons are absorbed in the control rods, which are made of boron, silver, indium, and cadmium. The control rods are lowered and raised in order to allow for more or less energy production. When the control rods are lowered further, fewer neutrons are able to travel through, and less energy is generated. The opposite happens when the bars are heightened.
Safety measures include the use of machinery to prevent human error from influencing any further problems, regular and constant system monitoring and testing to determine any possible problems, and technology to prevent the fuel from doing any damage to the plant itself.
Nuclear power plants were determined to have a lifespan of about 40 years, but now the US fleet of nuclear power plants is predicted to last 50-70 years. Technically however, they don’t have age limits, because they are constantly changing parts of nuclear reactors even before any problems occur, to ensure they don’t.
Nuclear reactors in the US are typically around 33% efficient. This means that for every three units of thermal energy that are being generated with a nuclear reactor, while one unit of electricity may go out onto the grid, two units of heat are lost, and are released into the environment.
Works Cited:
"Primordial Nuclide." Wikipedia. Wikimedia Foundation, 15 Apr. 2014. Web. 25 Apr.
2014. <http://en.wikipedia.org/wiki/Primordial_nuclide>.
"Uranium-235." Wikipedia. Wikimedia Foundation, 22 Apr. 2014. Web. 25 Apr. 2014.
<http://en.wikipedia.org/wiki/Uranium-235>.
"U.S. Energy Information Administration - EIA - Independent Statistics and
Analysis." How Much Electricity Does a Typical Nuclear Power Plant
Generate? N.p., n.d. Web. 25 Apr. 2014.
<http://www.eia.gov/tools/faqs/faq.cfm?id=104&t=3>.
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"Operating at 98% Efficiency, U.S. Nuclear Plants Play Vital Role in Beating Sweltering
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<http://en.wikipedia.org/wiki/Nuclear_fission#Input>.
Question Number 6
Breeze Maestas
How much radiation is the surrounding environment subjected to from a properly function nuclear power plant?
“An operating nuclear power plant produces very small amounts of radioactive gases and liquids, as well as small amounts of direct radiation. If you lived within 50 miles of a nuclear power plant, you would receive an average radiation dose of about 0.01 millirem per year. To put this in perspective, the average person in the United States receives an exposure of 300 millirem per year from natural background sources of radiation.” An average american is exposed to 620 millirems per year, we are exposed to all different types of radiation in our daily lives such as cell phones, the sun, xrays, etc. There is just as much to be feared in this area as there is with nuclear power plants. As Americans we are exposed to a steady stream of radiation in our everyday lives and the small added amount, due to exposure to nuclear power plants does not raise your levels to a dangerous high.
What risk for nuclear meltdown exists in light water reactors in the U.S.?
In the United States, there are 104 nuclear reactors. Some of these nuclear power plants have had emergency shut downs in the past, indicating the possibility of a more unexpected shut downs in the future. In May of 2011, five of the nuclear reactors were shut down due to emergencies. Severe weather such as hurricanes, tsunamis and tornadoes can affect the nuclear power plants. Along with natural disasters, these plants are also at risk through a few other instabilities including the type of reactor, either boiling water reactor or a pressurized water reactor; the age of the reactor; power level of the reactor. Researchers have found that the boiling water reactors are less able to prevent the release of radiation in the event of a natural disaster. Most nuclear power plants have a lifespan of 40 years. However, the Nuclear Regulatory Commission has declared that several nuclear power plants can operate for 60 years. As the plant gets older, so do the components, potentially making for a weaker, less secure plant. Lastly, the power production of a plant determines the level of wear and tear. In some cases, the reactors have been pushed past their limit to produce more energy than they are designed for, weakening all back-up systems. The United States also has organizations that aim to monitor and ensure all nuclear power plants are practicing the safest methods of energy production. Additionally, all power plants are closely monitored and improved emergency systems have been developed to increase safety. Through all of these safety procedures, there is still the slim chance that a natural disaster could occur and that unpredictable accident may lead to a meltdown or other damage to the plant.
What are potential risks to nuclear power plants from events like natural disaster and terrorist attacks?
There are always risks such as natural disasters and terrorist attacks. Natural disasters are more possible and a greater risk to the common public than terrorist attacks. Terrorist attacks are not extremely probable or thought to be very problematic. The reason for that explanation is, the only thing that could be of any harm is if, an object (i.e. a plane or missile) crashed into the nuclear plant site, then hit the core of the reactor. The probability of that happening is very low. Natural disasters are more of a problem because they cause more damage and are stronger as well as less predictable.
What safety features are being built in light water reactors in the U.S.?
There are a few ideas being proposed about making the light water reactors safer as well as safer. One idea is looking into advanced pumps, heating and cooling systems and turbines. Another plan that is being implemented in the United States mandates that the reactor be built with “32 per cent fewer valves, 35 per cent fewer pumps, and 45 per cent less pipe than a traditional power.”
How much radioactive waste is produced by a typical light water reactor?
“Thermal-neutron reactors are the most common type of reactor, and light water reactors are the most common type of thermal-neutron reactor. In the OECD countries, some 300 million tons of toxic wastes are produced each year, but conditioned radioactive wastes amount to only 81,000 m3 per year. A typical 1000 MWe light water reactor will generate (directly and indirectly) 200-350 m3 low- and intermediate-level waste per year.”
Question Number 7
Breeze Maestas
What radionuclides are typically in radioactive waste and in what concentrations?
‘There are six levels of radioactive wastes:
1. exempt waste
2. very short lived waste
3. very low level waste
4. low level waste
5. intermediate waste
6. high level waste’
what are the half lives of the radionuclides found in radioactive waste and in what concentrations?
“Plutonium has at least 15 different isotopes, all of which are radioactive. The most common ones are Pu-238, Pu-239, and Pu-240. Pu-238 has a half-life of 87.7 years. Plutonium-239 has a half-life of 24,100, and Pu-240 has a half-life 6,560 years. The isotope Pu-238 gives off useable heat, because of its radioactivity. Iodine is also commonly found in radioactive substances. Plutonium has at least 15 different isotopes, all of which are radioactive. The most common ones are Pu-238, Pu-239, and Pu-240. Pu-238 has a half-life of 87.7 years. Plutonium-239 has a half-life of 24,100, and Pu-240 has a half-life 6,560 years. The isotope Pu-238 gives off useable heat, because of its radioactivity.”
What are the types of decay the radionuclides in radioactive waste undergo? WHat are their decay energies?
“Most naturally occurring radioactive materials and many fission products; undergo radioactive decay through a series of transformations (loss of particles or electromagnetic energy from an unstable nucleus) rather than in a single step. Until the last step, these radionuclides emit energy or particle with each transformation and become another radionuclide. Man-made elements, which are all heavier than uranium and unstable, undergo decay in this way. This decay chain, or decay series, ends in a stable nuclide.”
Work Cited
"Categorisation of Radioactive Waste." European Nuclear Safety Regulators Group. European Nuclear Safety Regulators Group, n.d. Web. 27 Apr. 2014.
"Decay Chains." EPA. Environmental Protection Agency, n.d. Web. 27 Apr. 2014.
"Frequently Asked Questions (FAQ) About Radiation Protection." NRC:. United States Nuclear Regulatory Committee, 11 Dec. 2012. Web. 27 Apr. 2014.
"Iodine." EPA. United States Environmental Protection Agency, n.d. Web.
"Plutonium." EPA. Environmental Protection Agency, n.d. Web. 27 Apr. 2014.
"Nuclear reactor safety systems."Wikipedia.N.p.: Wikimedia Foundation, 2014. Wikipedia.Web. 27 Apr. 2014.
"Backgrounder on Radioactive Waste." NRC:.N.p., n.d. Web. 27 Apr. 2014
Question Number 8 –Josh Davoust
What are emissions from nuclear power plants?
How have the emissions from nuclear power plants affected local air quality as compared to other forms of energy production?
Nuclear power produces very few emissions. The only direct emission from a nuclear power plant is depleted fuel rods that require special disposal. With consideration to the entire life of a nuclear power plant there are still less emissions than other power sources. Although no green house gasses (GHG) are directly emitted by nuclear power production the extraction and disposal of uranium account for some GHG. Regardless, nuclear power still produces far less GHG than any other nonrenewable energy source. World Nuclear Association reported that the tonnes of CO2 emitted per GWh by nuclear(29) is lower than all energy sources apart from hydro(26) and geothermal(26); natural gas emitted 888 t/GWh and 499 t/GWh from natural gas (this study used the life time emission). For surrounding areas a very minimal amount of radiation is emitted, however more radiation is released by a coal plant and this amount is a fraction of a percent of the radiation we are exposed to. The largest emission concern for nuclear power is the radioactive material. The waste is stored until it is no longer hazardous, this can be indefinitely.
Works Cited
"Life Cycle Assessment Harmonization Results and Findings." NREL: Energy Analysis -. N.p., n.d. Web. 30 Apr. 2014. <http://www.nrel.gov/analysis/sustain_lca_results.html>.
"Life-Cycle Emissions Analyses." Nuclear Energy Institute -. N.p., n.d. Web. 27 Apr. 2014.
"Nuclear Helps Exelon Achieve Emissions Goal." Lifecycle GHG Emissions of Electricity Generation Sources. N.p., n.d. Web. 30 Apr. 2014. <http://www.world-nuclear.org/WNA/Publications/WNA-Reports/Lifecycle-GHG-Emissions-of-Electricity-Generation/>.
Question Number 9 –Josh Davoust
What are environmental and safety considerations for the storage of nuclear waste?
When the life of nuclear fuel cells is depleted they become nuclear waste. Radioactive waste can also be considered anything that has been irradiated. Nuclear Waste poses challenges because it waste is harmful to most life and is not easily discarded. Once the fuel rods are no longer in use at the power plant they must be cooled and stored. Depleted rods still emit very large amounts of radiation and living organisms cannot be exposed to them. The spent rods emit alpha, beta, and gamma radiation. Measures are required to prevent this radiation from irritating anything. Waste is categorized as low-level, intermediate-level, and high-level radioactive waste based on the amount of time until it will no longer be hazardous.
Low and intermediate-level waste does not need to be store as securely or for as long. Most countries including the US have facilities to store low and intermediate waste. High level waste is waste that must be stored for incredibly long amounts of time, between thousands to billions of years. No country currently operates a high level civilian nuclear waste facility, a facility for power plant waste. Currently waste is stored in temporary containment locations.
High level waste facilities have not been opened due to the effort required to complete such a facility. The facility would have to withstand the most strenuous conditions such as natural disasters. Currently the most viable option is deep earth burial. Deep burial would prevent any radiation from reaching the surface and harming life on earth. If containment of waste were to leak it would cause irreparable damage to the ecosystem. Leaked radiation mutates DNA and would force areas to become inhabitable. Because of the time it would take before the waste is no longer a threat storage facilities would have to be completely inaccessible forever.
Works Cited
Findlay, Trevor. THE FUTURE OF NUCLEAR ENERGY TO 2030 AND ITS IMPLICATIONS FOR SAFETY, SECURITY AND NONPROLIFERATION. Issue brief. N.p.: Cigionline, n.d. Print.
"National Policies." : Radioactive Waste Management. N.p., n.d. Web. 30 Apr. 2014. <http://www.world-nuclear.org/info/nuclear-fuel-cycle/nuclear-wastes/appendices/radioactive-waste-management-appendix-3--national-policies/>.
"NDA Attacked over Magnox Contract." Radioactive Waste Management. N.p., n.d. Web. 30 Apr. 2014. <http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Nuclear-Wastes/Radioactive-Waste-Management/>.
"Storage of Spent Nuclear Fuel." NRC:. N.p., n.d. Web. 29 Apr. 2014. <http://www.nrc.gov/waste/spent-fuel-storage.html>.
Question Number 10 –Riley Wanzak
Describe the science involved in global climate change and how it relates to emissions from nuclear power pants and fossil fuel power plants.
As we use energy in the form or transportation, production and consumption we produce a gas, which is regularly occurring, but not at the rate it is now. It all involves the greenhouse effect, a vital and delicate system for life on Earth.
As we receive light from the sun it is either reflected back to space of absorbed into the environment. The environment then releases this energy as infrared radiation, some of this radiation is again released some of it is contained to warm the Earth. But as this delicate filter that releases the infrared radiation becomes bombarded with more carbon dioxide more of the heat is contained, ultimately warming the atmosphere. If still confused think of the atmosphere as a shirt around the Earth. This shirt is breathable and moderates a temperature perfect for our comfort. But now the shirt becomes clogged and contains more heat then suitable for element such as ice caps.
Over time as man has the increases need for energy, the increase has also been found in the gases emitted into the atmosphere. Due to the warming of the environment vital elements of nature are becoming scarce, mainly elements involving a cooler climate conditions. Ice caps are receding into the ocean; Shorter and shorter winters have been recorded. These are the effects of climate change and they will only get worse in the future.
Cleaner efforts have been achieved to reduce this carbon footprint. The production of nuclear power shows the use in a highly efficient process. With mining and transportation emissions still present this method does still produce emissions but little at the tail pipe of the nuclear reactor. Posing a much more efficient production than coal or natural gas which both emit greenhouse gases after the combustion of the substance.
Work Cited
"The Greenhouse Effect." EPA. Environmental Protection Agency, 9 Aug. 2013. Web. 28 Apr. 2014.
"Greenhouse Effect." Wikipedia. Wikimedia Foundation, 30 Apr. 2014. Web. 29 Apr. 2014.
Question Number 11 –Bella Kidd
What are the environmental and safety issues associated with the mining and refining of nuclear fuel?
Health risks that come at the cost of nuclear power production are plentiful. Cases of water contamination with radioactive substances has occurred around over a dozen different nuclear sites around just the United States alone. The process of mining materials used in nuclear power plants such as uranium and titanium run a very high risk of water contamination to near by rivers and streams as well as ground water supplies. In addition to water contamination, exposure to radioactive material can sometimes be deadly, causing health problems and cancer. Through the history of nuclear disasters, it has been observed that there has been a definite negative effect on human health caused by nuclear power plants along with infertility, health problems, and deadly cancers among people in communities even far away from original nuclear site.
Where is uranium mined and approximately how much is available in the US? In the world?
The three largest producers of uranium are Kazakhstan, Canada and Australia. These countries account for 63% of worldwide uranium production. Only about 3% is mined here in the United States, however.
Annually, about 50,500 metric tons of uranium are produced worldwide (Uranium)(2009) . Given this statistic, the United States mines roughly 1,515 metric tons of uranium annually.
(Image source: Wikipedia)
How much of our energy needs can uranium provide?
Uranium is a heavy metal that can be used as an abundant source of concentrated energy. A very small amount of uranium can be converted into a very large amount of energy. Uranium provides about 12% of the world’s electricity which is generated in nuclear reactors. This amounts to more than 2500 kWh (kilowatts) each year. This basic electricity is provided to people worldwide to power homes, businesses, and more.
Aside from providing basic electricity, uranium can be used as a military source of fuel. Bomb-grade uranium is highly enriched compared to uranium for domestic power use(up to 90% U-235 instead of up to 5%). Uranium is ideal for nuclear bombs because of a process that it undergoes called nuclear fission, which occurs when a neutron and a target nucleus collide. A powerful chain reaction is created and a significant amount of energy is created as a result.
Not only is uranium used in just energy form; it can be used in physical form as well. Uranium can also be used as an additive for glass and ceramics, a toner in photography, or as an additive for the preparation of biological samples for electrons and other minor applications.
What are the best estimates for the purely financial cost of nuclear power generated electricity?
In the production of nuclear energy, total cost is based upon the costs associated with the purchasing of uranium, conversion, enrichment, and fabrication services along with storage and shipment costs, and any inventory charges.
For a typical BWR (boiling water reactor) or PWR (pressurized water reactor), the approximate cost of fuel for one reload (replaces one third of the core) is roughly $40 million, based on a 18-month typical refueling cycle. In 2012, the average fuel cost at a nuclear power plant was 0.75 cents per kWh. Since nuclear plants are refueled every 18-24 months, fluctuating fuel prices are not a concern compared to natural gas and oil power plants.
Included in the price of nuclear power are the costs related to waste management. About $35.8 billion (or 1/10th of a cent per kWh of electricity generated at nuclear power plants since 1983 with interest) is devoted to funds committed for the Nuclear Waste Fund. Per each nuclear power plant, about $300 million to $500 million covers the cost of estimated used fuel ($100 million) and site restoration (about $300 million).
What are the levelized costs per kWh?
Levelized energy cost (LEC, also known as Levelized Cost of Energy, abbreviated LCOE) is the price at which electricity must be generated from a specific source to in order to break even over the lifetime of the project. This economic assessment includes all costs of running a nuclear power plant such as initial investment, maintenance, fuel cost, and more. In 2012, the estimated total system levelized cost of advanced nuclear plants was 96.1 USD/mWh (megawatts) (Costs).
What are fuel costs annually or per kWh? Construction costs for a new plant? Operating and maintenance costs?
As mentioned previously, the average cost of fuel at a nuclear power plant was 0.75 cents/kWh. Annually, the levelized cost of advanced nuclear plants was 96.1 USD/mWh in total.
The construction cost estimates for new nuclear power plants vary greatly and have increased significantly in recent years. Total costs of a new nuclear plant are estimated to be within the range of $5,500/kWh to $8,100/kWh. This translates to a cost between $6 billion and $9 billion for each 1,100 MW plant established. Just in the years from 2000-2002, the costs for new nuclear units were between $1,200/kWh and $1,500/kWh.
The average non-fuel operation and maintenance cost for a nuclear power plant in 2012 was reported to be 1.65 cents/kWh.
Works Cited
"7 Reasons Why Nuclear Power Is Bad for the Environment and the Nation." Examiner.com. N.p., n.d. Web. 27 Apr. 2014.
"Costs: Fuel, Operation, Waste Disposal & Life Cycle." Nuclear Energy Institute -. N.p., n.d. Web. 28 Apr. 2014.
"Radioactive Waste and Uranium Mines." :: WorstPolluted.org : Projects Reports. N.p., n.d. Web. 24 Apr. 2014.
"The University of Michigan Health Physics Web Site: Risks of Nuclear Power." The University of Michigan Health Physics Web Site: Risks of Nuclear Power. N.p., n.d. Web. 26 Apr. 2014.
"Uranium Mining." Wikipedia. Wikimedia Foundation, Apr. 2014. Web. 27 Apr. 2014.
"What Is Uranium? How Does It Work?" What Is Uranium? How Does It Work. N.p., n.d. Web. 29 Apr. 2014.
Question Number 12 - Reuben Barnes
Science Involved in Global Climate Change/Relation to Emissions of Nuclear Power Plants
Reuben Barnes
· What is the greenhouse effect and how is it related to global climate change?
o The greenhouse effect is when gasses that can absorb the energy that is released from the sun and back out from the earth. When the sun’s rays penetrate the Earth they are absorbed by the ground, then this energy is released back out. Now some of that energy goes back in space but the rest of it is captured by greenhouse gasses that are in the atmosphere. (They collect this heat energy and hold it in the atmosphere, delaying its passage back out of the atmosphere.)These gasses are the only things that can capture the infrared rays that are released from the sun. This is necessary for our planet but at the same time if there is an excessive amount of gasses to capture heat then it will negatively affect the planet. The greenhouse effect is necessary because those gasses that are trapped inside keep the Earth warm, without it the temperature would decrease to an unlivable point; the earth would be so cold that we would freeze to death. However if there are too many gasses that are trapped in the atmosphere then it can cause a huge increase in heat, this is because when there are extra greenhouse gasses in the air they capture an excessive amount which can result with a unusual release of heat. The increase in heat is caused by all the carbon dioxide that is released into the air, with all of the machinery that requires gasoline or fossil fuels all emit a large amount of carbon dioxide. So due to all of the emissions the global climate is heated up and then unbalanced. This climate change can affect a lot of things that are on the planet, for example (Rising temperature also means melting glaciers and rising sea level through addition of melt water to the oceans. Sea level rose about 1 foot during the last century, mostly from thermal expansion of the oceans.). This increase in temperature will clearly affect us in the end which will damage our society and can be very deadly.
o
· What are greenhouse gases and what about their structure makes them greenhouse gases?
o Greenhouse gasses are certain gasses that are in the atmosphere, these gasses are water vapor, carbon dioxide, methane ozone, and nitrous oxide. Each of these absorbs the infrared radiation that is emitted from the sun. Once they have captured some of that energy they can slowly release it back into the atmosphere which then creates heat. Each one of these specific gasses are bonded by two or more molecules, now each one of these bonds are loose, so when they absorb the energy they will vibrate and can release the heat again. All other types of gasses have to tight bonds and therefore do not contribute to the greenhouse effect.
o
Sites:
· "The Greenhouse Effect." Greenhouse Effect: Background Material. N.p., n.d. Web. 29 Apr. 2014.
· "The Greenhouse Effect." The Greenhouse Effect. N.p., n.d. Web. 30 Apr. 2014.
· http://www.columbia.edu/~vjd1/greenhouse.gif
· http://www.ucar.edu/learn/images/radiate.gif
Science Involved in Global Climate Change/Relation to Emissions of Nuclear Power Plants