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Mrs. Sealy APES I.Mining Law of 1872 – encouraged mineral exploration and mining. 1. First declare your belief that minerals on the land. Then spend.

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Presentation on theme: "Mrs. Sealy APES I.Mining Law of 1872 – encouraged mineral exploration and mining. 1. First declare your belief that minerals on the land. Then spend."— Presentation transcript:


2 Mrs. Sealy APES

3 I.Mining Law of 1872 – encouraged mineral exploration and mining. 1. First declare your belief that minerals on the land. Then spend $500 in improvements, pay $100 per year and the land is yours 2. Domestic and foreign companies take out $2-$3 billion/ year 3. Allows corporations and individuals to claim ownership of U.S. public lands. 4. Leads to exploitation of land and mineral resources.

4 "This archaic, 132-year-old law permits mining companies to gouge billions of dollars worth of minerals from public lands, without paying one red cent to the real owners, the American people. And, these same companies often leave the unsuspecting taxpayers with the bill for the billions of dollars required to clean up the environmental mess left behind." -- Senator Dale Bumpers (D- AR, retired)

5 Nature and Formation of Mineral Resources A. Nonrenewable Resources – a concentration of naturally occurring material in or on the earths crust that can be extracted and processed at an affordable cost. Non-renewable resources are mineral and energy resources such as coal, oil, gold, and copper that take a long period of time to produce.

6 Nature and Formation of Mineral Resources 1. Metallic Mineral Resources – iron, copper, aluminum 2. Nonmetallic Mineral Resources – salt, gypsum, clay, sand, phosphates, water and soil. 3. Energy resource: coal, oil, natural gas and uranium

7 Nature and Formation of Mineral Resources B. Identified Resources – deposits of a nonrenewable mineral resource that have a known location, quantity and quality based on direct geological evidence and measurements C. Undiscovered Resources– potential supplies of nonrenewable mineral resources that are assumed to exist on the basis of geologic knowledge and theory (specific locations, quantity and quality are not known) D. Reserves – identified resources of minerals that can be extracted profitably at current prices. Other Resources – resources that are not classified as reserves.

8 Ore Formation 1.Magma (molten rock) – magma cools and crystallizes into various layers of mineral containing igneous rock.

9 Ore Formation Hydrothermal Processes: most common way of mineral formation A.Gaps in sea floor are formed by retreating tectonic plates B.Water enters gaps and comes in contact with magma C.Superheated water dissolves minerals from rock or magma D.Metal bearing solutions cool to form hydrothermal ore deposits. E.Black Smokers – upwelling magma solidifies. Miniature volcanoes shoot hot, black, mineral rich water through vents of solidified magma on the seafloor. Support chemosynthetic organisms.

10 Ore Formation Manganese Nodules (pacific ocean)– ore nodules crystallized from hot solutions arising from volcanic activity. Contain manganese, iron copper and nickel.

11 Ore Formation 3. Sedimentary Processes – sediments settle and form ore deposits. A.Placer Deposits – site of sediment deposition near bedrock or course gravel in streams B.Precipitation: Water evaporates in the desert to form evaporite mineral deposits. (salt, borax, sodium carbonate) C.Weathering – water dissolves soluble metal ions from soil and rock near earths surface. Ions of insoluble compounds are left in the soil to form residual deposits of metal ores such as iron and aluminum (bauxite ore).

12 Methods For Finding Mineral Deposits A.Photos and Satellite Images B.Airplanes fly with radiation equipment and magnetometers C.Gravimeter (density) D.Drilling E.Electric Resistance Measurement F.Seismic Surveys G.Chemical analysis of water and plants

13 Mineral Extraction Surface Mining: overburden (soil and rock on top of ore) is removed and becomes spoil. pit mining – digging holes 2.Dredging – scraping up underwater mineral deposits 3.Area Strip Mining – on a flat area an earthmover strips overburden 4.Contour Strip Mining – scraping ore from hilly areas

14 Subsurface Mining: 1.dig a deep vertical shaft, blast underground tunnels to get mineral deposit, remove ore or coal and transport to surface 2.disturbs less land and produces less waste 3.less resource recovered, more dangerous and expensive 4.Dangers: collapse, explosions (natural gas), and lung disease

15 Environmental Impacts of Mineral Resources A. Scarring and disruption of land, B. Collapse or subsidence C. Wind and water erosion of toxic laced mine waste D. Air pollution – toxic chemicals E. Exposure of animals to toxic waste F. Acid mine drainage: seeping rainwater carries sulfuric acid ( acid comes from bacteria breaking down iron sulfides) from the mine to local waterway Google earth

16 StepsEnvironmental Effects exploration, extraction Mining Disturbed land; mining accidents; health hazards; mine waste dumping; oil spills and blowouts; noise; ugliness; heat Solid wastes; radioactive material; air, water, and soil pollution; noise; safety and health hazards; ugliness; heat Processing transportation, purification, manufacturing Use transportation or transmission to individual user, eventual use, and discarding Noise; ugliness thermal water pollution; pollution of air, water, and soil; solid and radioactive wastes; safety and health hazards; heat Fig. 14.6, p. 326

17 Percolation to groundwater Leaching of toxic metals and other compounds from mine spoil Acid drainage from reaction of mineral or ore with water Spoil banks Runoff of sediment Surface Mine Subsurface Mine Opening Leaching may carry acids into soil and ground water supplies Fig. 14.7, p. 326

18 Surface mining Metal ore Separation of ore from gangue Scattered in environment Recycling Discarding of product Conversion to product Melting metal Smelting Fig. 14.8, p. 327

19 A. Life Cycle of Metal Resources (fig. 14-8) Mining Ore A. Ore has two components: gangue(waste) and desired metal B. Separation of ore and gangue which leaves tailings C. Smelting (air and water pollution and hazardous waste which contaminates the soil around the smelter for decades) D. Mel ting Metal E. Conversion to product and discarding product

20 Economic Impact on Mineral Supplies A. Mineral prices are low because of subsidies: depletion allowances and deduct cost of finding more B. Mineral scarcity does not raise the market prices C. Mining Low Grade Ore: Some analysts say all we need to do is mine more low grade ores to meet our need 1. We are able to mine low grade ore due to improved technology –2. The problem is cost of mining and processing, availability of fresh water, environmental impact

21 PresentDepletion time A Depletion time B Depletion time C Time Production C B A Recycle, reuse, reduce consumption; increase reserves by improved mining technology, higher prices, and new discoveries Recycle; increase reserves by improved mining technology, higher prices, and new discoveries Mine, use, throw away; no new discoveries; rising prices Fig. 14.9, p. 329

22 Fig , p. 329

23 A. Mining Oceans 1.Minerals are found in seawater, but occur in too low of a concentration 2.Continental shelf can be mined 3.Deep Ocean are extremely expensive to extract (not currently viable)

24 A. Substitutes for metals 1. Materials Revolution 2.Ceramics and Plastics 3.Some substitutes are inferior (aluminum for copper in wire) 4.Will be difficult to find substitutes for helium, manganese, phosphorus and copper

25 Evaluating Energy Sources What types of energy do we use? 1. 99% of our heat energy comes directly from the sun (renewable fusion of hydrogen atoms) 2. Indirect forms of solar energy (renewable) –wind –hydro –biomass

26 Mined coal Pipeline Pump Oil well Gas well Oil storage CoalOil and Natural GasGeothermal Energy Hot water storage Contour strip mining Pipeline Drilling tower Magma Hot rock Natural gas Oil Impervious rock Water Oil drilling platform on legs Floating oil drilling platform Valves Underground coal mine Water is heated and brought up as dry steam or wet steam Water penetrates down through the rock Area strip mining Geothermal power plant Coal seam Fig , p. 332

27 Primitive Hunter– gatherer Early agricultural Advanced agricultural Early industrial Modern industrial (other developed nations) Modern industrial (United States) SocietyKilocalories per Person per Day 260, ,000 60,000 20,000 12,000 5,000 2,000 Fig , p. 333

28 World Natural Gas 23% Coal 22% Biomass 12% Oil 30% Nuclear power 6% Hydropower, geothermal, Solar, wind 7% Fig a, p. 333

29 United States Oil 40% Coal 22% Natural Gas 22% Nuclear power 7% Hydropower geothermal, solar, wind 5% Biomass 4% Fig b, p. 333

30 20th Century Trends 1. Coal use decreases from 55% to 22% 2. Oil increased from 2% to 30% 3. Natural Gas increased from 0% to 25% 4. Nuclear increased from 0% to 6%

31 Year Contribution to total energy consumption (percent) Wood Coal Oil Nuclear Hydrogen Solar Natural gas Fig , p. 334

32 Evaluating Energy Sources Evaluating Energy Resources; Take into consideration the following: –Availability –net energy yield –Cost –environmental impact

33 Space Heating Passive solar Natural gas Oil Active solar Coal gasification Electric resistance heating (coal-fired plant) Electric resistance heating (natural-gas-fired plant) Electric resistance heating (nuclear plant) Fig a, p. 335

34 High-Temperature Industrial Heat Surface-mined coal Underground-mined coal Natural gas Oil Coal gasification Direct solar (highly concentrated by mirrors, heliostats, or other devices) Fig b, p. 335

35 Transportation Natural gas Gasoline (refined crude oil) Biofuel (ethyl alcohol) Coal liquefaction Oil shale Fig c, p. 335

36 Net Energy Net Energy – total amount of energy available from a given source minus the amount of energy used to get the energy to consumers (locate, remove, process and transport) G. Net Energy Ratio - ratio of useful energy produced to the useful energy used to produce it.

37 Oil A.Petroleum/Crude Oil – thick liquid consisting of hundreds of combustible hydrocarbons and small concentrations of nitrogen, sulfur, and oxygen impurities. B.Produced by the decomposition of dead plankton that were buried under ancient lakes and oceans. It is found dispersed in rocks. um/knowl/4/2index.htm?origin.html

38 Oil Life Cycle 1.Primary Oil Recovery a.drill well b.pump out light crude oil 1:14

39 Secondary Oil Recovery a.pump water under pressure into a well to force heavy crude oil toward the well b.pump oil and water mixture to the surface c.separate oil and water d.reuse water to get more oil

40 Tertiary Oil Recovery a.inject detergent to dissolve the remaining heavy oil b.pump mixture to the surface c.separate out the oil d.reuse detergent

41 Transport oil to the refinery (pipeline, truck, boat)

42 Oil refining – heating and distilling based on boiling points of the various petrochemicals found in the crude oil. (fractional distillation in a cracking tower)

43 Diesel oil Asphalt Grease and wax Naphtha Heating oil Aviation fuel Gasoline Gases Furnace Fig , p. 337 Heated crude oil

44 Conversion to product a.Industrial organic chemicals b.Pesticides c.Plastics d.Synthetic fibers e.Paints f.Medicines g.Fuel

45 . Location of World Oil Supplies 1. 64% Middle East (67% OPEC – 11 countries) –a. Saudi Arabia (26%) –b. Iraq, Kuwait, Iran, (9-10% each) 2.Latin America (14%) (Venezuela and Mexico) 3.Africa (7%) 4.Former Soviet Union (6%) 5.Asia (4%) (China 3%) 6.United States (2.3%) we import 52% of the oil we use 7.Europe (2%)

46 MEXICO UNITEDSTATES CANADA Pacific Ocean Atlantic Ocean Grand Banks Gulf of Alaska Valdez ALASKA Beaufort Sea Prudhoe Bay Arctic Ocean Coal Gas Oil High potential areas Prince William Sound Arctic National Wildlife Refuge Trans Alaska oil pipeline Fig , p. 338

47 Year Oil price per barrel ($) (1997 dollars) Fig , p. 339

48 World Year Annual production (x 10 9 barrels per year) 2,000 x 10 9 barrels total Fig a, p. 339

49 United States Year Annual production (x 10 9 barrels per year) Proven reserves: 34 x 10 9 barrels 200 x 10 9 barrels total 1975 Undiscovered: 32 x 10 9 barrels Fig b, p. 339

50 Nuclear power Natural gas Oil Coal Synthetic oil and gas produced from coal Coal-fired electricity 17% 58% 86% 100% 150% 286% Fig , p. 339

51 Low land use Easily transported within and between countries High net energy yield Low cost (with huge subsidies) Ample supply for 42–93 years Advantages Moderate water pollution Releases CO 2 when burned Air pollution when burned Artificially low price encourages waste and discourages search for alternatives Need to find substitute within 50 years Disadvantages Fig , p. 340

52 How long will the oil last 1. Identified Reserve will last 53 years at current usage rates 2.Known and projected supplies are likely to be 80% depleted within 42 to 93 years depending on usage rate –US oil supplies are expected to be depleted within 15 to 48 years depending on the annual usage rate

53 Heavy Oils Oil Shale – fine grained sedimentary rock containing solid organic combustible material called kerogenShale Oil – kerogen distilled from oil shale. a. could meet U.S. crude oil demand for 40 years at current usage rates (Colorado, Utah and Wyoming public lands) Tar Sand – mixture of clay sand and water containing bitumen (high sulfur heavy oil)

54 Fig , p. 340

55 Above Ground Conveyor Spent shale Pipeline Retort Mined oil shale Air compressors Shale oil storage Impurities removed Hydrogen added Crude oil Refinery Air injection Shale layer Underground Shale heated to vaporized kerogen, which is condensed to provide shale oil Sulfur and nitrogen compounds Fig , p. 341 Shale oil pumped to surface

56 Hydrogen added Impurities removed Synthetic crude oil Refinery Pipeline Tar sand is mined.Tar sand is heated until bitumen floats to the top. Bitumen vapor Is cooled and condensed. Fig , p. 341


58 AdvantagesDisadvantages Moderate existing supplies Large potential supplies High costs Low net energy yield Large amount of water needed to process Severe land disruption from surface mining Water pollution from mining residues Air pollution when burned CO 2 emissions when burned Fig , p. 342

59 XI. Natural Gas Natural Gas is a mixture of 50-90% methane (CH4) by volume; contains smaller amounts of ethane, propane, butane and toxic hydrogen sulfide. B. Conventional natural gas - lies above most reservoirs of crude oil C. Unconventional deposits - include coal beds, shale rock, deep deposits of tight sands and deep zones that contain natural gas dissolved in hot hot water

60 Mined coal Pipeline Pump Oil well Gas well Oil storage CoalOil and Natural GasGeothermal Energy Hot water storage Contour strip mining Pipeline Drilling tower Magma Hot rock Natural gas Oil Impervious rock Water Oil drilling platform on legs Floating oil drilling platform Valves Underground coal mine Water is heated and brought up as dry steam or wet steam Water penetrates down through the rock Area strip mining Geothermal power plant Coal seam Fig , p. 332

61 XI. Natural Gas Gas Hydrates - an ice-like material that occurs in underground deposits (globally) Liquefied Petroleum Gas (LPG) - propane and butane are liquefied and removed from natural gas fields. Stored in pressurized tanks. Liquefied Natural Gas (LNG) - natural gas is converted at a very low temperature (-184oC)

62 Where is the worlds natural gas? Russia and Kazakhstan - 40% Iran - 15% Qatar - 5% Saudi Arabia - 4% Algeria - 4% United States - 3% Nigeria - 3% Venezuela - 3%

63 Advantages: 1. Cheaper than Oil 2. World reserves - >125 years 3. Easily transported over land (pipeline) 4. High net energy yield 5. Produces less air pollution than other fossil fuels 6. Produces less CO2 than coal or oil 7. Extracting natural gas damages the environment much less that either coal or uranium ore 8. Easier to process than oil 9. Can be used to transport vehicles 10. Can be used in highly efficient fuel cells

64 AdvantagesDisadvantages Good fuel for fuel cells and gas turbines Low land use Easily transported by pipeline Moderate environ- mental impact Lower CO 2 emissions than other fossil fuels Less air pollution than other fossil fuels Low cost (with huge subsidies) High net energy yield Ample supplies (125 years) Sometimes burned off and wasted at wells because of low price Shipped across ocean as highly explosive LNG Methane (a greenhouse gas) can leak from pipelines Releases CO 2 when burned Fig , p. 342

65 Disadvantages: 1. When processed, H2S and SO2 are released into the atmosphere 2. Must be converted to LNG before it can be shipped (expensive and dangerous) 3. Conversion to LNG reduces net energy yield by one-fourth 4. Can leak into the atmosphere; methane is a greenhouse gas that is more potent than CO2.

66 XII. Coal –Coal is a solid, rocklike fossil fuel; formed in several stages as the buried remains of ancient swamp plants that died during the Carboniferous period (ended 286 million years ago); subjected to intense pressure and heat over millions of years. –Coal is mostly carbon (40-98%); small amount of water, sulfur and other materials

67 Three types of coal lignite (brown coal) bituminous coal (soft coal) anthracite (hard coal) Carbon content increases as coal ages; heat content increases with carbon content

68 Increasing moisture content Increasing heat and carbon content Peat (not a coal) Lignite (brown coal) Bituminous Coal (soft coal) Anthracite (hard coal) Heat Pressure Heat Partially decayed plant matter in swamps and bogs; low heat content Low heat content; low sulfur content; limited supplies in most areas Extensively used as a fuel because of its high heat content and large supplies; normally has a high sulfur content Highly desirable fuel because of its high heat content and low sulfur content; supplies are limited in most areas Fig , p. 344

69 Coal Extraction Subsurface Mining - labor intensive; worlds most dangerous occupation (accidents and black lung disease Surface Mining - three types 1. Area strip mining 2. contour strip mining 3. open-pit mining

70 Mined coal Pipeline Pump Oil well Gas well Oil storage CoalOil and Natural GasGeothermal Energy Hot water storage Contour strip mining Pipeline Drilling tower Magma Hot rock Natural gas Oil Impervious rock Water Oil drilling platform on legs Floating oil drilling platform Valves Underground coal mine Water is heated and brought up as dry steam or wet steam Water penetrates down through the rock Area strip mining Geothermal power plant Coal seam Fig , p. 332

71 Why we need coal Coal provides 25% of worlds commercial energy (22% in US). Used to make 75% of worlds steel Generates 64% of worlds electricity

72 Coal-Fired Electric Power Plant Coal is pulverized to a fine dust and burned at a high temperature in a huge boiler. Purified water in the heat exchanger is converted to high-pressure steam that spins the shaft of the turbine. The shaft turns the rotor of the generator (a large electromagnet) to produce electricity.

73 . Coal-Fired Electric Power Plant Air pollutants are removed using electrostatic precipitators (particulate matter) and scrubbers (gases). Ash is disposed of in landfills. Sulfur dioxide emissions can be reduced by using low- sulfur coal.

74 I. Worlds Coal Supplies US - 66% of worlds proven reserves Identified reserves should last 220 years at current usage rates. Unidentified reserves could last about 900 years

75 . Pros and Cons of Solid Coal Advantages Worlds most abundant and dirtiest fossil fuel, High net energy yield

76 AdvantagesDisadvantages Low cost (with huge subsidies) High net energy yield Ample supplies (225–900 years) Releases radioactive particles and mercury into air High CO 2 emissions when burned Severe threat to human health High land use (including mining) Severe land disturbance, air pollution, and water pollution Very high environmental impact Fig , p. 344

77 Disadvantages: harmful environmental effects -mining is dangerous (accidents and -black lung disease) -harms the land and causes water pollution -Causes land subsidence -Surface mining causes severe land disturbance and soil erosion -Surface mined land can be restored - involves burying toxic materials, returning land to its original contour, and planting vegetation (Expensive and not often done) -Acids and toxic metals drain from piles of water materials -Coal is expensive to transport -Cannot be used in sold form in cars (must be converted to liquid or gaseous form) -Dirtiest fossil fuel to burn releases CO, CO2, SO2, NO, NO2, particulate matter (flyash), toxic metals and some radioactive elements. -Burning Coal releases thousands of times more radioactive particles into the atmosphere per unit of energy than does a nuclear power plant -Produces more CO2 per unit of energy than other fossil fuels and accelerates global warming. -A severe threat to human health (respiratory disease)

78 Clean Coal Technology. Fluidized-bed combustion - developed to burn coal more cleanly and efficiently. Use of low sulfur coal - reduces SO2 emission Coal gasification – uses coal to produce synthetic natural gas (SNG). Coal liquefaction - produce a liquid fuel - methanol or synthetic gasoline

79 Calcium sulfate and ash Air Air nozzles Water Fluidized bed Steam Flue gases CoalLimestone Fig , p. 345

80 Raw coal Pulverizer Air or oxygen Steam Pulverized coal Slag removal Recycle unreacted carbon (char) Raw gases Clean Methane gas Recover sulfur Methane (natural gas) 2C Coal +O2O2 2CO CO+3H 2 CH 4 +H2OH2O Remove dust, tar, water, sulfur Fig , p. 345

81 AdvantagesDisadvantages Large potential supply Vehicle fuel Low to moderate net energy yield Higher cost than coal High environmental impact Increased surface mining of coal High water use Higher CO2 emissions than coal Fig , p. 346

82 Clean Coal Technology Synfuels - can be transported by pipeline inexpensively; burned to produce electricity; burned to heat houses and water; used to propel vehicles.

83 XIII. Nuclear Energy A. Three reasons why nuclear power plants were developed in the late 1950s: 1. Atomic Energy Commission promised electricity at a much lower cost than coal 2. US Govt paid ~1/4 the cost of building the first reactors 3. Price Anderson Act protected nuclear industry from liability in case of accidents

84 Gigawatts of electricity Year Fig a, p. 348

85 Gigawatts of electricity Year Fig b, p. 348

86 Why is nuclear power on the decline? B. Globally, nuclear energy produces only 17% of worlds electricity (6% of commercial energy) -huge construction overruns -high operating costs -frequent malfunctions -false assurances -cover-ups by government and industry -inflated estimates of electricity use -poor management -Chernobyl -Three Mile Island -public concerns about safety, cost and disposal of radioactive wastes

87 C. How a Nuclear Reactor Works Nuclear fission of Uranium-235 and Plutonium-239 releases energy that is converted into high-temperature heat. This rate of conversion is controlled. The heat generated can produce high- pressure steam that spins turbines that generate electricity.

88 Periodic removal and storage of radioactive wastes and spent fuel assemblies Periodic removal and storage of radioactive liquid wastes Pump Steam Small amounts of Radioactive gases Water Black Turbine Generator Waste heatElectrical power Hot water output Condenser Cool water input Pump Waste heat Useful energy 25 to 30% Waste heat Water source (river, lake, ocean) Heat exchanger Containment shell Uranium fuel input (reactor core) Emergency core Cooling system Control rods Moderator Pressure vessel Shielding Coolant passage Fig , p. 346 Coolant Hot coolant

89 Front endBack end Uranium mines and mills Ore and ore concentrate (U 3 O 8 ) Geologic disposal of moderate- and high-level radioactive wastes High-level radioactive waste or spent fuel assemblies Uranium tailings (low level but long half-life) Conversion of U 3 O 8 to UF 6 Processed uranium ore Uranium-235 as UF 6 Enrichment UF 6 Enriched UF 6 Fuel fabrication Spent fuel reprocessing Plutonium-239 as PuO 2 (conversion of enriched UF 6 to UO 2 and fabrication of fuel assemblies) Fuel assemblies Reactor Spent fuel assemblies Interim storage Under water Open fuel cycle today Prospective closed end fuel cycle Decommissioning of reactor Decommissioning of reactor Spent fuel assemblies Spent fuel assemblies Fig , p. 347

90 D. Light-water reactors (LWR) 1. Core containing 35,000-40,000 fuel rods containing pellets of uranium oxide fuel. Pellet is 97% uranium-238 (nonfissionable isotope) and 3% uranium-235 (fissionable). 2. Control rods - move in and out of the reactor to regulate the rate of fission 3. Moderator - slows down the neutrons so the chain reaction can be kept going [ liquid water in pressurized water reactors; solid graphite or heavy water (D2O) ]. 4. Coolant - water to remove heat from the reactor core and produce steam

91 Decommissioning Power Plants 1/3 of fuel rod assemblies must be replaced every 3-4 years. They are placed in concrete lined pools of water (radiation shield and coolant). A. Nuclear wastes must be stored for 10,000 years B. After years of operation, the plant must be decommissioned by 1. dismantling it 2. putting up a physical barrier, or 3. enclosing the entire plant in a tomb (to last several thousand years)

92 Low risk of accidents because of multiple safety systems (except in 35 poorly designed and run reactors in former Soviet Union and Eastern Europe) Moderate land use Moderate land disruption and water pollution (without accidents) Emits 1/6 as much CO2 as coal Low environmental impact (without accidents) Large fuel supply Spreads knowledge and technology for building nuclear weapons No acceptable solution for long-term storage of radioactive wastes and decommissioning worn-out plants Catastrophic accidents can happen (Chernobyl) High environmental impact (with major accidents) Low net energy yield High cost (even with large subsidies) AdvantagesDisadvantages Fig , p. 349

93 Coal Ample supply High net energy yield Very high air pollution High CO2 emissions 65,000 to 200,000 deaths per year in U.S. High land disruption from surface mining High land use Low cost (with huge subsidies) Nuclear Ample supply of uranium Low net energy yield Low air pollution (mostly from fuel reprocessing) Low CO2 emissions (mostly from fuel reprocessing) About 6,000 deaths per year in U.S. Much lower land disruption from surface mining Moderate land use High cost (with huge subsidies) Fig , p. 349

94 F. Advantages of Nuclear Power: 1. Dont emit air pollutants 2. Water pollution and land disruption are low

95 G. Nuclear Power Plant Safety 1. Very low risk of exposure to radioactivity 2. Three Mile Island - March 29, 1979; No. 2 reactor lost coolant water due to a series of mechanical failures and human error. Core was partially uncovered 3. Nuclear Regulatory Commission estimates there is a 15-45% chance of a complete core meltdown at a US reactor during the next 20 years. 4. US National Academy of Sciences estimates that US nuclear power plants cause 6000 premature deaths and 3700 serious genetic defects each year.

96 Steam generator Water pumps Crane for moving fuel rods Turbines Reactor Cooling pond Cooling pond Reactor power output was lowered too much, making it too difficult to control. Additional water pump to cool reactor was turned on. But with low power output and extra drain on system, water didnt actually reach reactor. Automatic safety devices that shut down the reactor when water and steam levels fall below normal and turbine stops were shut off because engineers didnt want systems to spoil experiment. Radiation shields Almost all control rods were removed from the core during experiment. Emergency cooling system was turned off to conduct an experiment. Fig , p. 350 Chernobyl

97 H. Low-Level Radioactive Waste 1. Low-level waste gives off small amounts of ionizing radiation; must be stored for years before decaying to levels that dont pose an unacceptable risk to public health and safety : low-level waste was put into drums and dumped into the oceans. This is still done by UK and Pakistan 3. Since 1970, waste is buried in commercial, government-run landfills. 4. Above-ground storage is proposed by a number of environmentalists : the NRC proposed redefining low-level radioactive waste as essentially nonradioactive. That policy was never implemented (as of early 1999).

98 I. High-Level Radioactive Waste 1. Emit large amounts of ionizing radiation for a short time and small amounts for a long time. Must be stored for about 240, Spent fuel rods; wastes from plants that produce plutonium and tritium for nuclear weapons.

99 J. Possible Methods of Disposal and their Drawbacks 1. Bury it deep in the ground 2. Shoot it into space or into the sun 3. Bury it under the Antarctic ice sheet or the Greenland ice cap 4. Dump it into descending subduction zones in the deep ocean 5. Bury it in thick deposits of muck on the deep ocean floor 6. Change it into harmless (or less harmful) isotopes 7. Currently high-level waste is stored in the DOE $2 billion Waste Isolation Pilot Plant (WIPP) near Carlsbad, NM. (supposed to be put into operation in 1999)

100 Clay bottom Up to 60 deep trenches dug into clay. As many as 20 flatbed trucks deliver waste containers daily. Barrels are stacked and surrounded with sand. Covering is mounded to aid rain runoff. Fig b, p. 351

101 What covers waste Clay Gravel Sand Compacted clay Soil Topsoil Grass Gravel Fig c, p. 351

102 Waste container Steel wall Several steel drums holding waste Lead shielding 2 meters wide 2–5 meters high Fig a, p. 351

103 Storage Containers Fuel rod Primary canister Overpack container sealed Fig c, p. 352

104 Underground Buried and capped Fig d, p. 352

105 Ground Level Unloaded from train Lowered down shaft Fig a, p. 352

106 Personnel elevator Air shaft Nuclear waste shaft 2,500 ft. (760 m) deep Fig b, p. 352

107 K. Worn-Out Nuclear Plants 1. Walls of the reactors pressure vessel become brittle and thus are more likely to crack. 2. Corrosion of pipes and valves

108 3. Decommissioning a power plant (3 methods have been proposed) A. immediate dismantling B. mothballing for years C. entombment (several thousand years) 4. Each method involves shutting down the plant, removing the spent fuel, draining all liquids, flushing all pipes, sending all radioactive materials to an approved waste storage site yet to be built.

109 Connection between Nuclear Reactors and the Spread of Nuclear Weapons 1. Components, materials and information to build and operate reactors can be used to produce fissionable isotopes for use in nuclear weapons. Los Alamos Muon Detector Could Thwart Nuclear Smugglers

110 M. Can We Afford Nuclear Power? 1. Main reason utilities, the government and investors are shying away from nuclear power is the extremely high cost of making it a safe technology. 2. All methods of producing electricity have average costs well below the costs of nuclear power plants.

111 N. Breeder Reactors 1. Convert nonfissionable uranium-238 into fissionable plutonium Safety: liquid sodium coolant could cause a runaway fission chain reaction and a nuclear explosion powerful enough to blast open the containment building. 3. Breeders produce plutonium fuel too slowly; it would take years to produce enough plutonium to fuel a significant number of other breeder reactors.

112 O. Nuclear Fusion 1. D-T nuclear fusion reaction; Deuterium and Tritium fuse at about 100 million degrees 2. Uses more energy than it produces

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