Reduce text and add an image. Put in active Absorbed + reflected + transmitted = 1
This image will be revised by Alyssa.
Turbine can spin on a vertical axis or a horizontal axis
This section talks about the history of wind turbines and the modern devices.
Stuctures, tree anything in the path of the wind will create turbulence which can negatively affect wind turbines. This is why horizontal wind turbines should not be near your house, on your roof or in the middle of cities…too much turbulence.
This is the equation for the power in the wind. (Don’t fear – there are only 2 equations in this presentation.) Each of the terms in this equation can tell us a lot about wind turbines and how they work. Lets look at wind speed (V), swept area (A), and density (Greek letter “rho,” ) one at a time. First, let’s look at wind speed, V. Because V is cubed in the equation, a small increase in V makes for a increase in power. (illustrated on next slide) (Click on the links at the bottom to get the values of both k and .)
First windmills were found in Persia. They were vertical axis and were used to grind grains and seeds. They were kind of like a waterwheel turned on its side. Most of the paddles were covered by a wall and wind would run through a narrow opening to push the blades.
Many have seen the Dutch windmills. Used to grind grains, seeds, pump water, saw lumber…these were fairly sophisticated devices. Used to cover much of New England coastline.
In 1888, Charles F. Brush invented a large wind turbine which created electricity. This enormous windmill produced enough electricity for about 10 homes. Brush’s invention was soon adapted and copied all over the world. Electricity generating wind turbines spread throughout Europe in the early 1900’s, and they soon appeared in the United States as well. In the 1930s Marcellus Jacobs producing an affordable small turbine called the Jacobs that provided electricity for homes and farms throughout rural America. However, these small American turbines faded away with the widespread installation of power lines through the end of the 1930s.
Close Up of a Bergey XL 1 a 1kW wind turbine. Produces 1000w at peak output. For more info www.bergey.com
Wind farms are like powerplants…we wire a bunch of them together transform the current and put it on the power lines. Some wind farms are very large 700MW that is as big as coal or nuclear power plant.
Wind Farm in the MidWest
Windfarm in VT called Searsburg…one of the first windfarms in the Northeast. Wind farm development in VT is very contentious now in VT.. Notice the black blades. Why do they do that……to reduce ice build up in cold weather. More info head tohttp://www.gmpvt.com/whoweare/searsburg.shtml
Many developers would like to move windfarms offshore because the wind are faster, smoother and they can be close to major population centers on the coast. This is very controversial in the US….we have a few planned offshore farms…CapeWind and Long Island…but nothing installed. Major complaints about offshore are related visual impact, navigation impact and lack of history. Check http://www.capewind.org/
There are quiet a few offshore wind farms in Europe near Holland, England, Ireland, Sweden and the Denmark. This one is off the coast of Copehagen.
The lack of cheap and easy lesson plans, kits and material is kind of strange as wind energy is the fastest growing energy resource in the world. For the last five years it has been growing at rate of 20-30%. A bit misleading b/c when you start with a small amount it easy to grow fast. Nuclear, Coal and Oil could never grow at those rates takes too long to build and there is too much generation out there.
Many people think wind turbines are noisy. While this may have been true in the past (it is still somewhat true on older smaller devices)…newer larger devices are much quieter.
Wind Incentives: Most of the incentives from the Federal Level are for large utility sized sytems…nothing is really enacted at the small wind at the federal level. The Wind Energy Production Tax Credit (PTC), is a per kilowatt-hour tax credit for wind-generated electricity. Available during the first 10 years of operation, it provides 1.5 cents per kWh credit adjusted annually for inflation. The adjusted credit amount for 2005 is 1.9 cents per kWh. Enacted as part of the Energy Policy Act of 1992, the credit has gone through several cycles of expiration and renewal. The inconsistent nature of this tax credit has been a significant challenge for the wind industry, creating uncertainty for long term planning and preventing steady market development. In July 2005, the PTC was &quot;seamlessly&quot; renewed for the first time when an extension through December 31, 2007 was included in the federal Energy Bill. Just recently is was extended until 12/31/08…some legislators are looking for a 5 year extension on top of that. The tax credit also is primarily useful for corporations and is difficult (but, not impossible) for other entities (farmers and individuals, schools, municipal utilities, etc.) to use effectively. (from Windustry). States have varying levels of support from tax incentives, buydown, etc depending on where you live…
US installed capacity has fluctuate due to incentive that come into affect and then expire…hard to run a highly capitalized industry in this kind of environment. Things have been getting a little better. Last round of incentives will expire in December 2008. Some in congress want to extend this another 5 years. One thing to explain here… 1 Megawatt of wind will generate enough power for about 300 homes. This depends on the type of device and where it is located. Most large turbines that you see today are rated at 1.5 Megawatts…meaning that at peak output (high winds) it will be producing about 1.5 Megawatts
One major complaint about wind is that its power is intermittent. It comes and goes without notice…well this is not true…we can predict the weather and wind… To deal with that issue wind engineers have teamed up with meteorologists to help improve the accuracy of predicting the windspeed so they can predict power output 2,4,8, 24 hours ahead of time. While not perfect this science is getting better and due to the nature of the grid if wind power plants can accurately predict power output the will act more like power plants.
Presentation on Solar energy, Wind energy and Nuclear energy.
Presentation on Wind energy, Solar energy & Nuclear energy. <ul><li>Ishan O. Trivedi. </li></ul><ul><li>TIFAC, Surat. </li></ul>
What is Solar Energy? <ul><li>Radiation Energy produced by the sun </li></ul><ul><li>Clean, renewable source of energy </li></ul><ul><li>Harnessed by solar collection methods such as solar cells </li></ul><ul><li>Converted into usable energy such as electricity </li></ul>Sources: http://www1.eere.energy.gov/solar/pv_systems.html http://thomashawk.com/hello/209/1017/1024/Staring%20at%20the%20Sun.jpg Photovoltaic (solar) panel Set of solar panels Sun and electrical power lines
Energy from the Sun is Abundant <ul><li>The Earth receives 174 petawatts (PW) of incoming solar radiation (insolation) at the upper atmosphere </li></ul><ul><li>Solar power systems installed in the areas defined by the dark disks could meet the world's current total energy demand </li></ul>Source: http://www.ez2c.de/ml/solar_land_area/
Solar energy…. <ul><li>Solar energy can be used in 2 ways: </li></ul><ul><li>- Passive solar energy: Direct use for heating/ lighting/ drying/ ventilation purposes. </li></ul><ul><li>- Active solar energy: Conversion to electricity with the aid of special instruments. </li></ul>
Passive solar energy… <ul><li>Architecture and urban planning: The common features of passive solar architecture are orientation relative to the Sun, compact proportion (a low surface area to volume ratio), selective shading (overhangs) and thermal mass. Eg. Green building concept. </li></ul><ul><li>Agriculture and horticulture: Techniques such as timed planting cycles, tailored row orientation, staggered heights between rows and the mixing of plant varieties can improve crop yields. </li></ul>
Solar lighting… <ul><li>Daylighting: The history of lighting is dominated by the use of natural light. </li></ul><ul><li>Hybrid solar lighting is an active solar method of providing interior illumination. HSL systems collect sunlight using focusing mirrors that track the Sun and use optical fibers to transmit it inside the building to supplement conventional lighting. </li></ul>
Solar thermal…… <ul><li>Water heating: Solar hot water systems use sunlight to heat water. </li></ul><ul><li>Heating, cooling and ventilation: Thermal mass is any material that can be used to store heat—heat from the Sun in the case of solar energy. Common thermal mass materials include stone, cement and water. </li></ul>
Solar thermal….. <ul><li>Water treatment: The method involves evaporation, distillation and condensation process. </li></ul><ul><li>Solar water disinfection (SODIS) involves exposing water-filled plastic polyethylene terephthalate (PET) bottles to sunlight for several hours. </li></ul><ul><li>Cooking: Solar cookers use sunlight for cooking, drying and pasteurization. </li></ul>
Solar Electric Power Plants <ul><li>Harness solar power to generate electricity </li></ul><ul><li>Main types: </li></ul><ul><ul><li>Solar thermal energy </li></ul></ul><ul><ul><ul><li>Has mirrored surface that reflects sunlight to heat up liquid to make steam to generate electricity </li></ul></ul></ul><ul><ul><li>Photovoltaic </li></ul></ul><ul><ul><ul><li>Uses photovoltaic cells that absorb direct sunlight. </li></ul></ul></ul>Sources: http://en.wikipedia.org/wiki/Solar_energ http://www.fplenergy.com/portfolio/solar/facts.shtml#glance Concentrated solar collector (parabolic) Array of mirrored solar collectors at FPL Energy site in California
Know the cotton experiment with magnifying glass ?
Solar Cells are Converters of Energy… <ul><li>Solar cells are devices that take light energy as input and convert it into electrical energy </li></ul>Light energy Solar cell - converts light energy to electricity Electrical energy (carried through wires)
Photovoltaic Solar Cells <ul><li>Generate electricity directly from sunlight </li></ul><ul><li>2 Main types: </li></ul><ul><ul><li>Single-crystal silicon (traditional) </li></ul></ul><ul><ul><ul><li>Widespread </li></ul></ul></ul><ul><ul><ul><li>Expensive to manufacture </li></ul></ul></ul><ul><ul><li>Dye-sensitized (“nano”) </li></ul></ul><ul><ul><ul><li>Newer, less proven </li></ul></ul></ul><ul><ul><ul><li>Inexpensive to manufacture </li></ul></ul></ul><ul><ul><ul><li>Flexible </li></ul></ul></ul>Silicon-based solar cell Dye-sensitized solar cell
… But Not All Energy is Converted Source: http://ebiomedia.com/prod/cyclops/images/image004.jpg <ul><li>Like chloroplasts in plants, solar cells can only absorb specific wavelengths of light. </li></ul><ul><li>In both, light that isn’t absorbed is either transmitted through or reflected back. </li></ul><ul><li>Whether a certain wavelength of lights gets absorbed depends on its energy. </li></ul>Chlorophyll molecules absorb blue and red light, but reflect green light
Light and its absorption…. <ul><li>Different colors of light have different wavelengths and different energies </li></ul>Source: http://www.mhhe.com/physsci/astronomy/arny/instructor/graphics/ch03/0305.html
Sources: http://members.aol.com/WSRNet/tut/absorbu.htm, http://csep10.phys.utk.edu/astr162/lect/light/absorption.html Single electron transition in an isolated atom <ul><li>Absorption occurs only when the energy of the light equals the energy of transition of an electron </li></ul>Light
So What Does this Mean for Solar Cells? <ul><li>In dye-sensitized solar cells… </li></ul><ul><ul><li>Transition from highest occupied molecular orbital (HOMO) to lowest unoccupied molecular orbital (LUMO) </li></ul></ul>Source: Original Images <ul><li>In single-crystal silicon solar cells… </li></ul><ul><ul><li>Transition to “conduction band” (excited states) from “valence band” (ground states) </li></ul></ul>
Dye-Sensitized and Silicon-based Solar Cells Compared <ul><li>Dye-Sensitized </li></ul><ul><ul><li>Relatively inexpensive </li></ul></ul><ul><ul><li>Need little TLC </li></ul></ul><ul><ul><li>Short return on investment </li></ul></ul>Sources: http://www.imo.uhasselt.be/polytech/images/zonnecel1.jpg http://www.norfolksolar.co.uk/img/system.gif <ul><li>Traditional </li></ul><ul><ul><li>Expensive </li></ul></ul><ul><ul><li>Need TLC </li></ul></ul><ul><ul><li>Long return on investment </li></ul></ul>
Solar Panel Use Today <ul><li>Large companies like Google, Walmart, and Microsoft use solar energy to partially power some of their facilities </li></ul>Solar panels on Microsoft building Solar panels being tested on Walmart store Sources: http://i.n.com.com/i/ne/p/2006/IMG_5396_550x367.jpg http://www.solarwall.de/assets/images/Walmart_SW.jpg
Parabolic Dishes and Troughs Because they work best under direct sunlight, parabolic dishes and troughs must be steered throughout the day in the direction of the sun. Collectors in southern CA.
Advantages of Solar energy to the environment... <ul><ul><li>It is a renewable energy. </li></ul></ul><ul><li>Sun is an ever-lasting source of energy. </li></ul><ul><ul><li>It is non-polluting. </li></ul></ul><ul><li>It does not release any green-house gases. Moreover, the production of solar cells also does not produce much green house gases. </li></ul><ul><ul><li>It does not produce any noise. </li></ul></ul><ul><li>Solar power does not produce any noise like wind energy or hydro energy. </li></ul>
Advantages of Solar energy to the environment... <ul><ul><li>Solar cells are recyclable. </li></ul></ul><ul><li>After the life of solar cells is finished, solar cells can be recycled to form functional solar cells. </li></ul><ul><ul><li>Solar energy is uniformly distributed all over the earth. </li></ul></ul><ul><li>Solar energy is available to all countries free of cost. Every country gets good amount of solar energy every day. No country can claim that they do not get solar energy. </li></ul><ul><li>Easy availability. </li></ul><ul><li>The photovoltaic cells which constitute most solar energy systems are usually made of silicon, one of the most common minerals found on Earth. That means that creating the components is extremely easy, doesn't require mining or drilling in a dangerous locale to produce </li></ul>
Disadvantages of solar energy.. <ul><ul><li>Solar energy is highly diffuse. </li></ul></ul><ul><li>We need special collectors in order to be able to use solar energy in an effective form. </li></ul><ul><ul><li>Currently, the efficiency of solar cells is very less. </li></ul></ul><ul><li>Today’s solar cells can generate only about 45 milliwatts per square inch. </li></ul><ul><ul><li>Solar energy is not available at night. </li></ul></ul><ul><li>Special storage facilities like batteries are needed to store solar energy. Life of batteries is only 4 years. </li></ul><ul><ul><li>Solar cells are very expensive. </li></ul></ul><ul><ul><li>Angle of incidence is very important while generating electricity with solar cells. Angle of incidence should be 90 degrees for maximum efficiency. This angle is difficult to maintain at all times. </li></ul></ul>
Environmental impacts of Solar energy….. <ul><li>Cadmium </li></ul><ul><li>Cadmium is used in cadmium telluride solar cells as a semiconductor to convert solar energy into electricity. Though used in very small amounts, it is extremely toxic and can build up in a given ecosystem if it isn't monitored. </li></ul>
WIND POWER - What is it? <ul><li>In laymen’s language, Air in motion is called wind. </li></ul><ul><li>All renewable energy (except tidal and geothermal power), ultimately comes from the sun </li></ul><ul><li>The earth receives 1.74 x 10 17 watts of power (per hour) from the sun </li></ul><ul><li>About one or 2 percent of this energy is converted to wind energy (which is about 50-100 times more than the energy converted to biomass by all plants on earth). </li></ul><ul><li>Differential heating of the earth’s surface </li></ul><ul><li>and atmosphere induces vertical and </li></ul><ul><li>horizontal air currents that are affected by </li></ul><ul><li>the earth’s rotation and contours of </li></ul><ul><li>the land WIND. </li></ul><ul><li>~ e.g.: Land Sea Breeze Cycle. </li></ul>
<ul><li>Winds are influenced by the ground surface at altitudes up to 100 meters. </li></ul><ul><li>Wind is slowed by the surface roughness and obstacles. </li></ul><ul><li>When dealing with wind energy, we are concerned with surface winds. </li></ul><ul><li>A wind turbine obtains its power input by converting the force of the wind into a torque (turning force) acting on the rotor blades. </li></ul><ul><li>The amount of energy which the wind transfers to the rotor depends on the density of the air, the rotor area and the wind speed. </li></ul><ul><li>The kinetic energy of a moving body is proportional to its mass (or weight). The kinetic energy in the wind thus depends on the density of the air, i.e. its mass per unit of volume. In other words, the "heavier" the air, the more energy is received by the turbine. </li></ul><ul><li>at 15° Celsius air weighs about 1.225 kg per cubic meter, but the density decreases slightly with increasing humidity. </li></ul>
WINDMILL DESIGN <ul><li>A Windmill captures wind energy and then uses a generator to convert it to electrical energy. </li></ul><ul><li>The design of a windmill is an integral part of how efficient it will be. </li></ul><ul><li>When designing a windmill, one must decide on the size of the turbine, and the size of the generator. </li></ul>
<ul><li>Wind Turbines: </li></ul><ul><li>Number of Blades: </li></ul><ul><li>Most common design is the three-bladed turbine. The most important reason is the stability of the turbine. A rotor with an odd number of rotor blades (and at least three blades) can be considered to be similar to a disc when calculating the dynamic properties of the machine. </li></ul><ul><li>A rotor with an even number of blades will give stability problems for a machine with a stiff structure. The reason is that at the very moment when the uppermost blade bends backwards, because it gets the maximum power from the wind, the lowermost blade passes into the wind shade in front of the tower. </li></ul>
Orientation <ul><li>Turbines can be categorized into two overarching classes based on the orientation of the rotor </li></ul><ul><li>Vertical Axis Horizontal Axis </li></ul>
Vertical Axis Turbines <ul><li>Advantages </li></ul><ul><li>Omnidirectional </li></ul><ul><ul><li>Accepts wind from any angle </li></ul></ul><ul><li>Components can be mounted at ground level </li></ul><ul><ul><li>Ease of service </li></ul></ul><ul><ul><li>Lighter weight towers </li></ul></ul><ul><li>Can theoretically use less materials to capture the same amount of wind </li></ul><ul><li>Disadvantages </li></ul><ul><li>Rotors generally near ground where wind poorer </li></ul><ul><li>Centrifugal force stresses blades </li></ul><ul><li>Poor self-starting capabilities </li></ul><ul><li>Requires support at top of turbine rotor </li></ul><ul><li>Requires entire rotor to be removed to replace bearings </li></ul><ul><li>Overall poor performance and reliability </li></ul><ul><li>Have never been commercially successful </li></ul>
Types of Electricity Generating Windmills <ul><li>Small ( 10 kW) </li></ul><ul><li>Homes </li></ul><ul><li>Farms </li></ul><ul><li>Remote Applications </li></ul><ul><li>(e.g. water pumping, telecom sites, icemaking) </li></ul><ul><li>Large (250 kW - 2+MW) </li></ul><ul><li>Central Station Wind Farms </li></ul><ul><li>Distributed Power </li></ul><ul><li>Intermediate </li></ul><ul><li>(10-250 kW) </li></ul><ul><li>Village Power </li></ul><ul><li>Hybrid Systems </li></ul><ul><li>Distributed Power </li></ul>
Calculation of Wind Power <ul><li>Power in the wind </li></ul><ul><ul><li>where, </li></ul></ul><ul><ul><ul><li> = Effect of air density, </li></ul></ul></ul><ul><ul><ul><li>A = Effect of swept area and </li></ul></ul></ul><ul><ul><ul><li>V = Effect of wind speed </li></ul></ul></ul>R Swept Area: A = πR 2 Area of the circle swept by the rotor (m 2 ). Power in the Wind = ½ρAV 3
Importance of Wind Speed <ul><li>No other factor is more important to the amount of power available in the wind than the speed of the wind </li></ul><ul><li>Power is a cubic function of wind speed </li></ul><ul><ul><li>V X V X V </li></ul></ul><ul><li>20% increase in wind speed means 73% more power </li></ul><ul><li>Doubling wind speed means 8 times more power </li></ul>
<ul><li>Advantages of Wind Power </li></ul><ul><li>The wind blows day and night, which allows windmills to produce electricity throughout the day. (Faster during the day) </li></ul><ul><li>Wind power is available in ample amounts in all coastal areas. </li></ul><ul><li>The decreasing cost of wind power and the growing interest in renewable energy sources should ensure that wind power will become a viable energy source worldwide. </li></ul>
Environmental advantages of wind power…. <ul><li>It does not produce any carbon dioxide. </li></ul><ul><li>It is a renewable energy. </li></ul><ul><li>There is no use of fossil fuels. </li></ul><ul><li>Almost 95% of the land in use can be used for farming/recreational purpose. </li></ul>
Wind Energy is the Fastest Growing Energy Source in the World!! US installed capacity grew a WHOPPING 45% in 2007!!!
Impacts of Wind Power: Noise <ul><li>Modern turbines are relatively quiet </li></ul><ul><li>Rule of thumb – stay about 3x hub-height away from houses </li></ul>
Attractiveness…. <ul><li>Large windmills generate more electricity, but move slowly and so have less attractiveness among people. </li></ul><ul><li>Small windmills( fast moving) have more attractiveness but generate less electricity. </li></ul>
Tax Credits <ul><li>Whenever, tax incentives have been removed, interest of investors has steeply decreased. </li></ul><ul><li>Tax incentives increase government expenditure and lead to fiscal deficit. </li></ul>
Brief History <ul><li>Nuclear energy was first discovered in 1934 by Enrico Fermi. The first nuclear bombs were built in 1945 as a result of the infamous Manhattan Project. The first plutonium bomb, code-named Trinity, was detonated on July 16, 1945 in New Mexico. On August 6 th 1945 the first uranium bomb was detonated over Hiroshima. Three days later a plutonium bomb was dropped on Nagasaki. There is over 200,000 deaths associated with these detonations. Electricity wasn’t produced with nuclear energy until 1951. </li></ul>Source: The Green Peace Book of the Nuclear Age by John May
Mass and energy <ul><li>Einstein suggested that mass and energy are related by E=mc 2 (c = 3.0 x 10 8 m/s) </li></ul><ul><li>E: energy, m: mass, c: speed of light </li></ul><ul><li>Converting the mass of one penny could </li></ul><ul><ul><li>provide the entire energy requirements for 700 people for one year </li></ul></ul><ul><ul><li>Power a space heater for 7000 years </li></ul></ul><ul><ul><li>That’s about $3 million worth of electricity </li></ul></ul><ul><li>Because mass and energy are related the law of conservation of energy and law of conservation of mass can be combined into the Law of Conservation of Mass - Energy </li></ul>
Electricity generation…. <ul><li>Electricity can be generated from nuclear energy by 2 methods: </li></ul><ul><li>Nuclear fission. </li></ul><ul><li>Nuclear fusion. </li></ul>
Nuclear fission <ul><li>The nuclei of heavy atoms are split under bombardment by neutrons. </li></ul>
Nuclear Fuel Cycle <ul><li>We will start the nuclear fuel cycle with a brief explanation of how nuclear energy works, the enrichment process, and then power reactors. Following will be information on Three Mile Island and Chernobyl, the risk of reactor leaks, and the impacts on the communities and the environment. Then we will discuss the nuclear weapons program, including the use of depleted uranium, Hiroshima and Nagasaki, weapons testing, and the effects on soldiers, victims, communities, and the environment. </li></ul>Source: http://www.sonic.net/~kerry/uranium.html
Mining <ul><li>Uranium ore is usually located aerially; core samples are then drilled and analyzed by geologists. The uranium ore is extracted by means of drilling and blasting. Mines can be in either open pits or underground. Uranium concentrations are a small percentage of the rock that is mined, so tons of tailings waste are generated by the mining process. </li></ul>Sources: http://www.anawa.org.au/mining/index.html and http://www.energyres.com.au/ranger/mill_diagram.pdf and http://www.world-nuclear.org/education/mining.htm
Milling & Leaching <ul><li>The ore is first crushed into smaller bits, then it is sent through a ball mill where it is crushed into a fine powder. The fine ore is mixed with water, thickened, and then put into leaching tanks where 90% of the uranium ore is leached out with sulfuric acid. Next the uranium ore is separated from the depleted ore in a multistage washing system. The depleted ore is then neutralized with lime and put into a tailings repository. </li></ul>Sources: http://www.anawa.org.au/mining/index.html and http://www.energyres.com.au/ranger/mill_diagram.pdf
Yellowcake <ul><li>Meanwhile, the uranium solution is filtered, and then goes through a solvent extraction process that includes kerosene and ammonia to purify the uranium solution. After purification the uranium is put into precipitation tanks—the result is a product commonly called yellowcake. </li></ul>Sources: http://www.anawa.org.au/mining/index.html and http://www.energyres.com.au/ranger/mill_diagram.pdf
Transportation <ul><li>In the final processes the yellow cake is heated to 800˚Celcius which makes a dark green powder which is 98% U 3 O 8 . The dark green powder is put into 200 liter drums and loaded into shipping containers and are shipped overseas to fuel nuclear power plants. </li></ul>Sources: http://www.anawa.org.au/mining/index.html and http://www.energyres.com.au/ranger/mill_diagram.pdf
Mining Leaders <ul><li>Australia and Canada are currently the biggest Uranium miners. The aforementioned process that takes place in Australia is exported because Australia does not have a nuclear energy program. The mining in Australian is primarily open pit, while the mining in Canada is mostly underground. Following is two charts—one is the major uranium producing countries, the other is of the major corporations that actually do the mining. </li></ul>Source: http://www.antenna.nl/wise/uranium/uwai.html
Production in 2000 Source: http://www.world-nuclear.org/search/index.htm Canada 10,682 Australia 7,578 Niger 2,895 Namibia 2,714 Uzbekistan 2,350 Russia (est) 2,000 Kazakhstan 1,752 USA 1,456 South Africa 878 China (est) 500 Ukraine (est) 500 Czech Republic 500 India (est) 200 France 319 others 422 Total world 34,746 company tonnes U Cameco 7218 Cogema 6643 WMC 3693 ERA 3564 Navoi 2400 Rossing 2239 KazAtomProm 2018 Priargunsky 2000
Conversion <ul><li>To enrich uranium it must be in the gas form of UF6. This is called conversion. The conversion diagram shown here is from Honeywell. First the yellow cake is converted to uranium dioxide through a heating process (this step was also mentioned in the mining process). Then anhydrous hydrofluoric acid is used to make UF4. Next the UF4 is mixed with fluorine gas to make uranium hexafluoride. This liquid is stored in steel drums and crystallizes. </li></ul>Source: http://www.gat.com/converdyn/dfcp.html
Enrichment <ul><li>Uranium enrichment increases the amount of U235 in comparison to U238. Domestic power plants use a mixture that is 3-5% U235, while “highly enriched uranium” is generally used for weapons, some research facilities, and naval reactors. Domestic reactors usually require fuel in the form of uranium dioxide and weapons use the enriched mix in the form of a metal. The conversion and enrichment process is very dangerous because not only is the uranium hexafluoride radioactive, it is also chemically toxic. In addition, if the uranium hexafluoride comes in contact with moisture it will release another very toxic chemical called hydrofluoric acid. There have been numerous accidents during the conversion and enrichment process. Depleted uranium is the waste that is generated from the enrichment process. </li></ul>Source: http://www.anawa.org.au/chain/enrichment.html
Fuel Fabrication <ul><li>After being enriched, the UF6 is taken to a fuel fabrication facility that presses the powder into small pellets. The pellets are put into long tubes. These tubes are called fuel rods. A fuel assembly is a cluster of these sealed rods. Fuel assemblies go in the core of the nuclear reactor. It takes approximately 25 tonnes of fuel to power one 1000 MWe reactor per year. The picture on the right is a fuel assembly. </li></ul>Source: http://www.world-nuclear.org/education/nfc.htm
Transportation <ul><li>Radioactive materials are transported from the milling location to the conversion location, then from the conversion location to the enrichment location, then from the enrichment location to the to the fuel fabrication facility, and finally to the power plant. These materials are transported in special containers by specialized transport companies. People involved in the transport process are trained to respond to emergencies. In the US, Asia, and Western Europe transport is mainly by truck, and in Russia mainly by train. Intercontinental transport is usually by ship, and sometimes by air. Since 1971 there has been over 20,000 shipments with no incidents and limited operator exposure. </li></ul>Source: http://www.world-nuclear.org/info/inf20print.htm Picture: http://www.ocrwm.doe.gov/wat/facts.shtml
Nuclear fission <ul><li>When a sufficient amount of fissionable material is brought together chain reaction occurs </li></ul>
Nuclear fission <ul><li>Splitting atoms and releasing a tremendous amount of heat. </li></ul>
Nuclear fission <ul><li>Approximately 20,000 times as much heat and energy is released from uranium fuels as from an equivalent amount of coal. </li></ul>
Reactor Types <ul><li>PRW —Pressurized Water Reactor—does not boil, but uses the pressure of the water to heat a secondary source of water that generates electricity. Most popular (accounts for 65% of reactors world wide). Considered a light water reactor. </li></ul><ul><li>BRW —Boiling Water Reactor—boils water (coolant) that makes steam to turn turbines. Conducive to internal contamination. Also considered a light water reactor. </li></ul><ul><li>RBMK —Graphite-moderated pressure tube boiling-water reactor similar to BWR but uses graphite and oxygen. Complex and difficult to examine. </li></ul><ul><li>CANDU —Canadian Deuterium Uranium—Doesn’t use enriched fuel. Has lots of tubes and internal contamination issues. </li></ul><ul><li>Magnox —Gas cooled reactor. Cooled with carbon dioxide or helium, and uses natural uranium. (UK and France). </li></ul><ul><li>AGR —Advanced Gas-cooled—also cooled with carbon dioxide or helium. Uses enriched uranium. (UK). </li></ul><ul><li>Fast Breeder —high temperature gas reactor. Uses U235, U238, and Plutonium 239. Very dangerous because it uses liquid sodium in the primary circuit and in inflammable with air and explosive with water. </li></ul>Source: www.world-nuclear.org/
Nuclear forces <ul><li>There are two opposing forces in the nucleus: </li></ul><ul><li>Electrostatic (+ve proton repels +ve proton) </li></ul><ul><li>Strong force (nucleons attract each other) </li></ul><ul><li>The strong force is stronger, but acts over a shorter distance. Adding more nucleons is favored with small nuclei but not with large </li></ul><ul><li>E.g. adding a proton to a small vs. large nucleus </li></ul>
Nuclear Fusion <ul><li>Fusion is combining together </li></ul><ul><li>the atoms are fused together rather than split apart </li></ul><ul><li>possibilities for nuclear fusion are much greater than those for nuclear fission. </li></ul>
<ul><li>Solar energy is any form of energy radiated by the sun, including light, radio waves, and X-rays. Thermonuclear fusion is the energy producing process which takes place continuously in the sun and stars. Nuclear fusion is a nuclear reaction in which nuclei combine to form more massive nuclei with the simultaneous release of energy. The combining of the different protons leads to the formation of a new element. In the core of the sun at temperatures of 10-15 million degrees Celsius , Hydrogen is converted to Helium providing more than enough energy to sustain life on earth. </li></ul><ul><li>Regions of the sun include the core, radiation zone, convection zone, and photosphere. Gases in the core are about 150 times as dense as water and reach temperatures as high as 16 million degrees. Nuclear fusion of the hydrogen atoms takes place in the core. </li></ul>NUCLEAR FUSION
<ul><li>In order for fusion reactions to occur, the particles must be hot enough (temperature), in sufficient number (density) and well contained (confinement time). These simultaneous conditions are represented by a fourth state of matter known as plasma . In a plasma, electrons are stripped from their nuclei. A plasma, therefore, consists of charged particles, ions and electrons. </li></ul><ul><li>Temperature upto several million degree centigrades are reached. There is no substance on earth that can tolerate this high temperatures. </li></ul><ul><li>So, how is plasma confined ? </li></ul>
<ul><li>Tokamak Technology: </li></ul><ul><li>Magnetic Confinement </li></ul>FUSION REACTORS Efforts to control fusion first relied on the principle of magnetic confinement, in which a powerful magnetic field traps a hot deuterium-tritium plasma long enough for fusion to begin. In November 1997, researchers exploiting the magnetic confinement approach created a fusion reaction that produced 65 percent as much energy as was fed into it to initiate the reaction. This milestone was achieved in England at the Joint European Torus, a tokamak facility--a doughnut-shaped vessel in which the plasma is magnetically confined. A commercial fusion reactor would have to produce far more energy than went into it to start or maintain the reaction.
At Princeton University's plasma physics laboratory in New Jersey, scientists have produced a controlled fusion reaction at the Tokamak Fusion Test Reactor there. During these reaction the temperature in the reactor surpassed three times that of the core of the sun.
Developments <ul><li>Nuclear fusion reactor is under construction at the Cadarache site in southern France. </li></ul><ul><li>It will be operational in 2011 AD. </li></ul><ul><li>Sources: </li></ul><ul><li>http://news.bbc.co.uk/2/hi/4629239.stm </li></ul><ul><li>http://en.wikipedia.org/wiki/ITER </li></ul>
Advantages of Nuclear energy.. <ul><li>It is a clean form of energy and does not generate any Carbon dioxide. </li></ul><ul><li>Nuclear power plants do not require a large amount of working space. </li></ul><ul><li>It is a highly concentrated form of energy. </li></ul><ul><li>It is very cheap. </li></ul>
Negative impacts of use of nuclear technology. <ul><li>Nuclear bombs. </li></ul><ul><li>Reactor mishandling. </li></ul><ul><li>Waste dumping (in case of fission energy). </li></ul><ul><li>Life of nuclear reactors is only 40-50 years. </li></ul>
Three Mile Island <ul><li>Three Mile Island is a pair of PRW’s. </li></ul><ul><li>The second one was built in a hurry for tax purposes (started operation on December 30, 1798 to meet deadline). On March 28, 1979, the Pilot Operated Relief Valve was stuck open and caused pressure to be released from the primary cooling system. The fuel rods came apart and radioactive material discharged into the sky. Two days later 3,500 pregnant women and children were evacuated. Although there were no official instructions to do so, many others left as well. Numerous residents in the aftermath developed various cancers and thyroid diseases. </li></ul>Source: The Green Peace Book of the Nuclear Age by John May; picture: http://www.libraries.psu.edu/crsweb/tmi/tmi.htm
Chernobyl <ul><li>Chernobyl had the RBMK design. In an experiment, technicians let the power of reactor 4 fall, and on April 26, 1986 the result was rapid power levels rising inside the core— melting fuel and causing a reactor containment breach—in addition to an internal hydrogen explosion. The top of the reactor blew off and spewed radioactive material into the atmosphere for 10 days. </li></ul>Source: The Green Peace Book of the Nuclear Age by John May Picture: http://www.chernobyl.co.uk/
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