chapter 16 nonrenewable energy. chapter overview questions what are the advantages and...

Chapter 16Chapter 16

Nonrenewable EnergyNonrenewable Energy

Chapter Overview QuestionsChapter Overview Questions

What are the advantages and disadvantages What are the advantages and disadvantages of conventional oil and nonconventional of conventional oil and nonconventional heavy oils?heavy oils?

What are the advantages and disadvantages What are the advantages and disadvantages of natural gas?of natural gas?

What are the advantages and disadvantages What are the advantages and disadvantages of coal and the conversion of coal to gaseous of coal and the conversion of coal to gaseous and liquid fuels?and liquid fuels?

Chapter Overview Questions (cont’d)Chapter Overview Questions (cont’d)

What are the advantages and disadvantages What are the advantages and disadvantages of conventional nuclear fission, breeder of conventional nuclear fission, breeder nuclear fission, and nuclear fusion?nuclear fission, and nuclear fusion?

Updates OnlineUpdates Online

The latest references for topics covered in this section can be found at The latest references for topics covered in this section can be found at the book companion website. Log in to the book’s e-resources page at the book companion website. Log in to the book’s e-resources page at www.thomsonedu.com to access InfoTrac articles. www.thomsonedu.com to access InfoTrac articles.

InfoTrac: Spent nuclear fuel edges closer to Yucca. InfoTrac: Spent nuclear fuel edges closer to Yucca. The Christian The Christian Science MonitorScience Monitor, July 27, 2006 p03., July 27, 2006 p03.

InfoTrac: Pollution From Chinese Coal Casts Shadow Around InfoTrac: Pollution From Chinese Coal Casts Shadow Around Globe. Keith Bradsher; David Barboza. Globe. Keith Bradsher; David Barboza. The New York TimesThe New York Times, , June 11, 2006 pA1(L).June 11, 2006 pA1(L).

InfoTrac: A Renewable Source, and Clean, But Not Without Its InfoTrac: A Renewable Source, and Clean, But Not Without Its Critics. Heather Timmons. Critics. Heather Timmons. The New York TimesThe New York Times, August 3, 2006 , August 3, 2006 pC1(L).pC1(L).

National GeographicNational Geographic: Half-Life: The Lethal Legacy of America’s : Half-Life: The Lethal Legacy of America’s Nuclear WasteNuclear Waste

Nuclear Energy InstituteNuclear Energy Institute Union of Concerned Scientists: EthanolUnion of Concerned Scientists: Ethanol

Video: Nuclear FalloutVideo: Nuclear Fallout

This video clip is available in CNN Today This video clip is available in CNN Today Videos for Environmental Science, 2004, Videos for Environmental Science, 2004, Volume VII. Instructors, contact your local Volume VII. Instructors, contact your local sales representative to order this volume, sales representative to order this volume, while supplies last.while supplies last.

Video: Kyoto ProtocolVideo: Kyoto Protocol

This video clip is available in CNN Today This video clip is available in CNN Today Videos for Environmental Science, 2004, Videos for Environmental Science, 2004, Volume VII. Instructors, contact your local Volume VII. Instructors, contact your local sales representative to order this volume, sales representative to order this volume, while supplies last.while supplies last.

Core Case Study: Core Case Study: How Long Will the Oil Party Last? How Long Will the Oil Party Last?

Saudi Arabia could supply the world with oil Saudi Arabia could supply the world with oil for about 10 years.for about 10 years.

The Alaska’s North Slope could meet the The Alaska’s North Slope could meet the world oil demand for 6 months (U.S.: 3 world oil demand for 6 months (U.S.: 3 years).years).

Alaska’s Arctic National Wildlife Refuge Alaska’s Arctic National Wildlife Refuge would meet the world demand for 1-5 would meet the world demand for 1-5 months (U.S.: 7-25 months).months (U.S.: 7-25 months).

Core Case Study: Core Case Study: How Long Will the Oil Party Last? How Long Will the Oil Party Last?

We have three We have three options:options: Look for more oil.Look for more oil. Use or waste less oil.Use or waste less oil. Use something else.Use something else.

Figure 16-1Figure 16-1

TYPES OF ENERGY RESOURCESTYPES OF ENERGY RESOURCES

About 99% of the energy we use for heat About 99% of the energy we use for heat comes from the sun and the other 1% comes comes from the sun and the other 1% comes mostly from burning fossil fuels.mostly from burning fossil fuels. Solar energy indirectly supports wind power, Solar energy indirectly supports wind power,

hydropower, and biomass.hydropower, and biomass. About 76% of the commercial energy we use About 76% of the commercial energy we use

comes from nonrenewable fossil fuels (oil, comes from nonrenewable fossil fuels (oil, natural gas, and coal) with the remainder natural gas, and coal) with the remainder coming from renewable sources.coming from renewable sources.


Nonrenewable energy resources and Nonrenewable energy resources and geothermal energy in the earth’s crust.geothermal energy in the earth’s crust.


Fig. 16-2, p. 357

Oil and natural gasOil and natural gasFloating oil drilling

platform Oil storage CoalCoalContour strip miningOil drilling

platform on legs

Geothermal Geothermal energyenergy

Hot water storageOil well

Pipeline Geothermal power plant

Gas well Valves Mined coal

Pump Area strip mining Drilling

tower

Pipeline

Impervious rock

Underground coal mineNatural gasWaterOil

Water is heated and brought up as dry

steam or wet steamWater

Coal seam Hot rock

Water penetrates

down through the rock

Magma


Commercial energy use by source for the Commercial energy use by source for the world (left) and the U.S. (right).world (left) and the U.S. (right).


Fig. 16-3a, p. 357

Nuclear power 6%

Hydropower, geothermal, solar, wind

7%Natural

gas 21%

REN

EWA

BLE 18%

Biomass 11%

Oil 33%

Coal 22%NO

NRENEWABLE 82%

World

Fig. 16-3b, p. 357

Hydropower geothermal, solar, wind

3%

Nuclear power 8

%R

EN

EW

AB

LE

8%

Coal 23%

Natural gas 23%

Oil 39%

Biomass 4%

NO

NR

ENEW

AB

LE 93%

United States


Net energy is the amount of high-quality Net energy is the amount of high-quality usable energy available from a resource after usable energy available from a resource after subtracting the energy needed to make it subtracting the energy needed to make it available.available.

Net Energy RatiosNet Energy Ratios

The higher the net energy ratio, the greater The higher the net energy ratio, the greater the net energy available. Ratios < 1 indicate the net energy available. Ratios < 1 indicate a net energy loss.a net energy loss.


Fig. 16-4, p. 358

Space HeatingSpace Heating

Passive solar 5.8Natural gas

Oil 4.5Active solar 1.9

Coal gasification 1.5Electric resistance heating (coal-fired plant) 0.4

0.4

Electric resistance heating (nuclear plant) 0.3

High-Temperature Industrial HeatHigh-Temperature Industrial Heat

28.2Surface-mined coalUnderground-mined coal 25.8

Natural gas 4.9Oil 4.7

Coal gasification 1.5Direct solar (highly concentrated by mirrors,

heliostats, or other devices)0.9

TransportationTransportation

Natural gas 4.9Gasoline (refined crude oil) 4.1

Biofuel (ethyl alcohol) 1.9Coal liquefaction 1.4

Oil shale 1.2

Electric resistance heating (natural-gas-fired plant)

4.9

OILOIL

Crude oil (petroleum) is a thick liquid Crude oil (petroleum) is a thick liquid containing hydrocarbons that we extract from containing hydrocarbons that we extract from underground deposits and separate into underground deposits and separate into products such as gasoline, heating oil and products such as gasoline, heating oil and asphalt.asphalt. Only 35-50% can be economically recovered Only 35-50% can be economically recovered

from a deposit.from a deposit. As prices rise, about 10-25% more can be As prices rise, about 10-25% more can be

recovered from expensive secondary extraction recovered from expensive secondary extraction techniques.techniques.• This lowers the net energy yield.This lowers the net energy yield.

OILOIL Refining crude oil:Refining crude oil:

Based on boiling Based on boiling points, components points, components are removed at are removed at various layers in a various layers in a giant distillation giant distillation column.column.

The most volatile The most volatile components with components with the lowest boiling the lowest boiling points are removed points are removed at the top.at the top.


Fig. 16-5, p. 359

Gases

Gasoline

Aviation fuel

Heating oil

Diesel oil

Naptha

Grease and wax

Asphalt

Heated crude oil

Furnace

OILOIL

Eleven OPEC (Organization of Petroleum Eleven OPEC (Organization of Petroleum Exporting Countries) have 78% of the world’s Exporting Countries) have 78% of the world’s proven oil reserves and most of the world’s proven oil reserves and most of the world’s unproven reserves.unproven reserves.

After global production peaks and begins a After global production peaks and begins a slow decline, oil prices will rise and could slow decline, oil prices will rise and could threaten the economies of countries that threaten the economies of countries that have not shifted to new energy alternatives.have not shifted to new energy alternatives.

OILOIL

Inflation-adjusted price of oil, 1950-2006.Inflation-adjusted price of oil, 1950-2006.Figure 16-6Figure 16-6

Fig. 16-6, p. 361

Oil

pri

ce p

er b

arre

l ($)

(2006 dollars)

Year

Case Study: U.S. Oil SuppliesCase Study: U.S. Oil Supplies

The U.S. – the world’s largest oil user – has The U.S. – the world’s largest oil user – has only 2.9% of the world’s proven oil reserves.only 2.9% of the world’s proven oil reserves.

U.S oil production peaked in 1974 (halfway U.S oil production peaked in 1974 (halfway production point).production point).

About 60% of U.S oil imports goes through About 60% of U.S oil imports goes through refineries in hurricane-prone regions of the refineries in hurricane-prone regions of the Gulf Coast.Gulf Coast.

OILOIL

Burning oil for Burning oil for transportation transportation accounts for 43% accounts for 43% of global COof global CO22

emissions.emissions.


Fig. 16-7, p. 363

Trade-OffsConventional Oil

Advantages Disadvantages

Ample supply for 42–93 years Need to find

substitutes within 50 years

Low cost (with huge subsidies)

Artificially low price encourages waste and discourages search for alternatives

High net energy yield

Easily transported within and between countries

Air pollution when burnedLow land use

Releases CO2 when burned

Technology is well developed

Efficient distribution system Moderate water

pollution

COCO22 Emissions Emissions

COCO22 emissions per unit of energy produced emissions per unit of energy produced

for various energy resources. for various energy resources. Figure 16-8Figure 16-8

Fig. 16-8, p. 363

Coal-fired electricity

286%

Synthetic oil and gas produced from coal

150%

Coal100%

Oil sand92%

Natural gas58%

Oil86%

Nuclear power fuel cycle

17%

Geothermal10%

How Would You Vote?How Would You Vote?

To conduct an instant in-class survey using a classroom response To conduct an instant in-class survey using a classroom response system, access “JoinIn Clicker Content” from the PowerLecture main system, access “JoinIn Clicker Content” from the PowerLecture main menu for Living in the Environment. menu for Living in the Environment.

Do the advantages of relying on conventional Do the advantages of relying on conventional oil as the world’s major energy resource oil as the world’s major energy resource outweigh its disadvantages? outweigh its disadvantages? a. No. The environmental, political, and economic a. No. The environmental, political, and economic

costs of petroleum are too high.costs of petroleum are too high. b. Yes. Petroleum is needed until suitable b. Yes. Petroleum is needed until suitable

alternatives can be developed and alternatives can be developed and commercialized. commercialized.

Heavy Oils from Oil Sand and Oil Heavy Oils from Oil Sand and Oil Shale: Will Sticky Black Gold Save Us?Shale: Will Sticky Black Gold Save Us? Heavy and tarlike oils from oil sand and oil Heavy and tarlike oils from oil sand and oil

shale could supplement conventional oil, but shale could supplement conventional oil, but there are environmental problems.there are environmental problems. High sulfur content.High sulfur content. Extracting and processing produces:Extracting and processing produces:

• Toxic sludgeToxic sludge• Uses and contaminates larges volumes of waterUses and contaminates larges volumes of water• Requires large inputs of natural gas which reduces net Requires large inputs of natural gas which reduces net

energy yield.energy yield.

Oil ShalesOil Shales

Oil shales contain Oil shales contain a solid a solid combustible combustible mixture of mixture of hydrocarbons hydrocarbons called called kerogenkerogen..


Heavy OilsHeavy Oils

It takes about 1.8 It takes about 1.8 metric tons of oil metric tons of oil sand to produce sand to produce one barrel of oil.one barrel of oil.


Fig. 16-10, p. 365

Trade-OffsHeavy Oils from Oil Shale

and Oil Sand Advantages Disadvantages

Moderate cost (oil sand)

High cost (oil shale)

Low net energy yield

Large potential supplies, especially oil sands in Canada

Large amount of water needed for processing

Easily transported within and between countries

Severe land disruption

Severe water pollutionEfficient

distribution system in place

Air pollution when burned

CO2 emissions when burned

Technology is well developed

NATURAL GASNATURAL GAS

Natural gas, consisting mostly of methane, is Natural gas, consisting mostly of methane, is often found above reservoirs of crude oil.often found above reservoirs of crude oil. When a natural gas-field is tapped, gasses are When a natural gas-field is tapped, gasses are

liquefied and removed as liquefied petroleum gas liquefied and removed as liquefied petroleum gas (LPG).(LPG).

Coal beds and bubbles of methane trapped Coal beds and bubbles of methane trapped in ice crystals deep under the arctic in ice crystals deep under the arctic permafrost and beneath deep-ocean permafrost and beneath deep-ocean sediments are unconventional sources of sediments are unconventional sources of natural gas.natural gas.


Russia and Iran have almost half of the Russia and Iran have almost half of the world’s reserves of conventional gas, and world’s reserves of conventional gas, and global reserves should last 62-125 years.global reserves should last 62-125 years.

Natural gas is versatile and clean-burning Natural gas is versatile and clean-burning fuel, but it releases the greenhouse gases fuel, but it releases the greenhouse gases carbon dioxide (when burned) and methane carbon dioxide (when burned) and methane (from leaks) into the troposphere.(from leaks) into the troposphere.


Some analysts see Some analysts see natural gas as the natural gas as the best fuel to help us best fuel to help us make the transition to make the transition to improved energy improved energy efficiency and greater efficiency and greater use of renewable use of renewable energy.energy.


Fig. 16-11, p. 368

Trade-Offs

Conventional Natural Gas


Ample supplies (125 years) Nonrenewable resource

High net energy yieldReleases CO2 when burnedLow cost (with huge

subsidies)

Methane (a greenhouse gas) can leak from pipelines

Lower CO2 emissions than other fossil fuels

Difficult to transfer from one country to another

Moderate environmental impact Shipped across ocean as

highly explosive LNG

Easily transported by pipeline

Sometimes burned off and wasted at wells because of low price

Low land use

Good fuel for fuel cells and gas turbines

Requires pipelines

Less air pollution than other fossil fuels

COALCOAL

Coal is a solid fossil fuel that is formed in Coal is a solid fossil fuel that is formed in several stages as the buried remains of land several stages as the buried remains of land plants that lived 300-400 million years ago.plants that lived 300-400 million years ago.


Fig. 16-12, p. 368

Increasing heat and carbon content

Increasing moisture content

Peat (not a coal)

Lignite (brown coal)

Bituminous

(soft coal)

Anthracite

(hard coal)Heat Heat Heat

Pressure Pressure Pressure

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. 16-12, p. 368

Highly desirable fuel because of its high heat content and low sulfur content;supplies are limited in most areas

Extensively usedas a fuel becauseof its high heat content and large supplies; normally has ahigh sulfur content

Low heat content;low sulfur content; limited supplies in most areas

Partially decayed plant matter in swamps and bogs; low heatcontent

Increasing heat and carbon content

Increasing moisture content

Peat(not a coal)

Lignite(brown coal)

Bituminous(soft coal)

Anthracite(hard coal)

Heat

Pressure

Heat

Pressure

Heat

Pressure

Stepped Art

Fig. 16-13, p. 369

Waste heat

Coal bunker TurbineCooling tower

transfers waste heat to

atmosphere

Generator

Cooling loop

Stack

Pulverizing mill

Condenser Filter

Boiler

Toxic ash disposal

COALCOAL

Coal reserves in the United States, Russia, Coal reserves in the United States, Russia, and China could last hundreds to over a and China could last hundreds to over a thousand years.thousand years. The U.S. has 27% of the world’s proven coal The U.S. has 27% of the world’s proven coal

reserves, followed by Russia (17%), and China reserves, followed by Russia (17%), and China (13%).(13%).

In 2005, China and the U.S. accounted for 53% In 2005, China and the U.S. accounted for 53% of the global coal consumption.of the global coal consumption.

COALCOAL

Coal is the most Coal is the most abundant fossil fuel, abundant fossil fuel, but compared to oil but compared to oil and natural gas it is and natural gas it is not as versatile, has not as versatile, has a high environmental a high environmental impact, and releases impact, and releases much more COmuch more CO22 into into

the troposphere.the troposphere.


Fig. 16-14, p. 370

Trade-Offs

Coal


Ample supplies (225–900 years)

Severe land disturbance, air pollution, and water pollutionHigh net

energy yield

High land use (including mining)

Low cost(with huge subsidies)

Severe threat to human healthWell-developed

mining and combustion technology High CO2

emissions when burnedAir pollution

can be reduced with improved technology (but adds to cost)

Releases radioactive particles and toxic mercury into air



Should coal use be phased out over the next Should coal use be phased out over the next 20 years?20 years? a. No. Coal is an abundant energy source and a. No. Coal is an abundant energy source and

we should continue to develop clean ways to use we should continue to develop clean ways to use it.it.

b. Yes. Mining and combusting coal create b. Yes. Mining and combusting coal create serious environmental impacts. serious environmental impacts.

COALCOAL

Coal can be converted into synthetic natural Coal can be converted into synthetic natural gas (SNG or syngas) and liquid fuels (such gas (SNG or syngas) and liquid fuels (such as methanol or synthetic gasoline) that burn as methanol or synthetic gasoline) that burn cleaner than coal.cleaner than coal. Costs are high.Costs are high. Burning them adds more COBurning them adds more CO22 to the troposphere to the troposphere

than burning coal.than burning coal.

COALCOAL

Since Since COCO22 is not is not

regulated as an air regulated as an air pollutantpollutant and costs are and costs are high, U.S. coal-high, U.S. coal-burning plants are burning plants are unlikely to invest in unlikely to invest in coal gasification.coal gasification.


Fig. 16-15, p. 371

Trade-Offs

Synthetic Fuels


Large potential supply

Low to moderate net energy yield

Higher cost than coal

Vehicle fuelRequires mining 50% more coal

High environmental impact

Moderate cost (with large government subsidies)

Increased surface mining of coal

High water useLower air pollution when burned than coal

Higher CO2 emissions than coal

NUCLEAR ENERGYNUCLEAR ENERGY

When isotopes of uranium and plutonium When isotopes of uranium and plutonium undergo controlled nuclear fission, the undergo controlled nuclear fission, the resulting heat produces steam that spins resulting heat produces steam that spins turbines to generate electricity.turbines to generate electricity. The uranium oxide consists of about 97% The uranium oxide consists of about 97%

nonfissionable uranium-238 and 3% fissionable nonfissionable uranium-238 and 3% fissionable uranium-235.uranium-235.

The concentration of uranium-235 is increased The concentration of uranium-235 is increased through an enrichment process.through an enrichment process.

Fig. 16-16, p. 372

Small amounts of radioactive gases

Uranium fuel input (reactor core)

Control rodsContainment shell

Heat exchanger

Steam Turbine Generator

Waste heat

Electric power

Hot coolant

Useful energy 25%–30%Hot

water outputPumpPump

Coolant Pump Pump

Moderator

Cool water input

Waste heat

Shielding Pressure vessel

Coolant passage

Water CondenserPeriodic removal and storage of radioactive wastes and spent fuel assemblies

Periodic removal and storage of radioactive liquid wastes

Water source (river, lake, ocean)


After three or four After three or four years in a reactor, years in a reactor, spent fuel rods are spent fuel rods are removed and stored removed and stored in a deep pool of in a deep pool of water contained in a water contained in a steel-lined concrete steel-lined concrete container.container.



After spent fuel rods are cooled considerably, After spent fuel rods are cooled considerably, they are sometimes moved to dry-storage they are sometimes moved to dry-storage containers made of steel or concrete.containers made of steel or concrete.


Fig. 16-18, p. 373

Decommissioning of reactorFuel assemblies

ReactorEnrichment of UF6 Fuel fabricationFuel fabrication

(conversion of enriched UF(conversion of enriched UF66

to UOto UO22 and fabrication of and fabrication of

fuel assemblies)fuel assemblies) Temporary storage of Temporary storage of spent fuel assemblies spent fuel assemblies underwater or in dry underwater or in dry caskscasks

Conversion of U3O8 to UF6

Uranium-235 as UFUranium-235 as UF66

Plutonium-239 as PuOPlutonium-239 as PuO22

Spent fuel Spent fuel reprocessingreprocessing

Low-level radiation Low-level radiation with long half-lifewith long half-life

Geologic disposal of moderate &

high-level radioactive

wastesOpen fuel cycle today

“Closed” end fuel cycle

What Happened to Nuclear Power?What Happened to Nuclear Power?

After more than 50 years of development and After more than 50 years of development and enormous government subsidies, nuclear enormous government subsidies, nuclear power has not lived up to its promise power has not lived up to its promise because:because: Multi billion-dollar construction costs.Multi billion-dollar construction costs. Higher operation costs and more malfunctions Higher operation costs and more malfunctions

than expected.than expected. Poor management.Poor management. Public concerns about safety and stricter Public concerns about safety and stricter

government safety regulations.government safety regulations.

Case Study: The Chernobyl Nuclear Case Study: The Chernobyl Nuclear Power Plant AccidentPower Plant Accident

The world’s worst nuclear power plant The world’s worst nuclear power plant accident occurred in 1986 in Ukraine.accident occurred in 1986 in Ukraine.

The disaster was caused by poor reactor The disaster was caused by poor reactor design and human error.design and human error.

By 2005, 56 people had died from radiation By 2005, 56 people had died from radiation released.released. 4,000 more are expected from thyroid cancer and 4,000 more are expected from thyroid cancer and

leukemia.leukemia.

NUCLEAR NUCLEAR ENERGYENERGY

In 1995, the World In 1995, the World Bank said nuclear Bank said nuclear power is too costly power is too costly and risky.and risky.

In 2006, it was found In 2006, it was found that several U.S. that several U.S. reactors were leaking reactors were leaking radioactive tritium into radioactive tritium into groundwater.groundwater.


Fig. 16-19, p. 376

Trade-Offs

Conventional Nuclear Fuel Cycle


Large fuel supply Cannot compete economically without huge government subsidies

Low environmental impact (without accidents) Low net energy yield

High environmental impact (with major accidents)

Emits 1/6 as much CO2 as coal

Catastrophic accidents can happen (Chernobyl)

Moderate land disruption and water pollution (without accidents)

No widely acceptable solution for long-term storage of radioactive wastes and decommissioning worn-out plants

Moderate land use

Low risk of accidents because of multiple safety systems (except for 15 Chernobyl-type reactors)

Subject to terrorist attacks

Spreads knowledge and technology for building nuclear weapons

NUCLEAR NUCLEAR ENERGYENERGY

A 1,000 megawatt A 1,000 megawatt nuclear plant is nuclear plant is refueled once a refueled once a year, whereas a year, whereas a coal plant coal plant requires 80 rail requires 80 rail cars a day.cars a day.


Fig. 16-20, p. 376

Coal vs. Nuclear

Trade-Offs

Coal Nuclear

Ample supply Ample supply of uranium

High net energy yield Low net energy yield

Very high air pollutionLow air pollution (mostly from fuel reprocessing)

High CO2 emissions Low CO2 emissions (mostly from fuel reprocessing)

High land disruption from surface mining Much lower land disruption

from surface mining

Low cost (with huge subsidies) High cost (even with huge subsidies)

High land use Moderate land use


Terrorists could attack nuclear power plants, Terrorists could attack nuclear power plants, especially poorly protected pools and casks especially poorly protected pools and casks that store spent nuclear fuel rods.that store spent nuclear fuel rods.

Terrorists could wrap explosives around small Terrorists could wrap explosives around small amounts of radioactive materials that are amounts of radioactive materials that are fairly easy to get, detonate such bombs, and fairly easy to get, detonate such bombs, and contaminate large areas for decades.contaminate large areas for decades.


When a nuclear reactor reaches the end of When a nuclear reactor reaches the end of its useful life, its highly radioactive materials its useful life, its highly radioactive materials must be kept from reaching the environment must be kept from reaching the environment for thousands of years.for thousands of years.

At least 228 large commercial reactors At least 228 large commercial reactors worldwide (20 in the U.S.) are scheduled for worldwide (20 in the U.S.) are scheduled for retirement by 2012.retirement by 2012. Many reactors are applying to extent their 40-Many reactors are applying to extent their 40-

year license to 60 years.year license to 60 years. Aging reactors are subject to embrittlement and Aging reactors are subject to embrittlement and

corrosion.corrosion.


Building more nuclear power plants will not Building more nuclear power plants will not lessen dependence on imported oil and will lessen dependence on imported oil and will not reduce COnot reduce CO22 emissions as much as other emissions as much as other

alternatives.alternatives. The nuclear fuel cycle contributes to COThe nuclear fuel cycle contributes to CO22

emissions.emissions. Wind turbines, solar cells, geothermal energy, Wind turbines, solar cells, geothermal energy,

and hydrogen contributes much less to COand hydrogen contributes much less to CO22

emissions.emissions.

NUCLEAR ENERGYNUCLEAR ENERGY Scientists disagree about the best methods Scientists disagree about the best methods

for long-term storage of high-level radioactive for long-term storage of high-level radioactive waste:waste: Bury it deep underground.Bury it deep underground. Shoot it into space.Shoot it into space. Bury it in the Antarctic ice sheet.Bury it in the Antarctic ice sheet. Bury it in the deep-ocean floor that is geologically Bury it in the deep-ocean floor that is geologically

stable.stable. Change it into harmless or less harmful isotopes.Change it into harmless or less harmful isotopes.

New and Safer ReactorsNew and Safer Reactors

Pebble bed Pebble bed modular reactor modular reactor (PBMR) are (PBMR) are smaller reactors smaller reactors that minimize the that minimize the chances of chances of runaway chain runaway chain reactions.reactions.


Fig. 16-21, p. 380

Each pebble contains about 10,000 uranium dioxide particles the size of a pencil point.

Pebble detailSilicon carbide

Pyrolytic carbon

Porous buffer

Uranium dioxide

Graphite shell Helium

TurbineGenerator

Pebble

Core Hot water output

RecuperatorReactor vessel Water

cooler

Cool water input

New and Safer ReactorsNew and Safer Reactors

Some oppose the pebble reactor due to :Some oppose the pebble reactor due to : A crack in the reactor could release radioactivity.A crack in the reactor could release radioactivity. The design has been rejected by UK and The design has been rejected by UK and

Germany for safety reasons.Germany for safety reasons. Lack of containment shell would make it easier Lack of containment shell would make it easier

for terrorists to blow it up or steal radioactive for terrorists to blow it up or steal radioactive material.material.

Creates higher amount of nuclear waste and Creates higher amount of nuclear waste and increases waste storage expenses.increases waste storage expenses.


Nuclear fusion is a nuclear change in which Nuclear fusion is a nuclear change in which two isotopes are forced together.two isotopes are forced together. No risk of meltdown or radioactive releases.No risk of meltdown or radioactive releases. May also be used to breakdown toxic material.May also be used to breakdown toxic material. Still in laboratory stages.Still in laboratory stages.

There is a disagreement over whether to There is a disagreement over whether to phase out nuclear power or keep this option phase out nuclear power or keep this option open in case other alternatives do not pan open in case other alternatives do not pan out.out.



Should nuclear power be phased out in the Should nuclear power be phased out in the country where you live over the next 20 to 30 country where you live over the next 20 to 30 years?years? a. No. In many countries, there are no suitable a. No. In many countries, there are no suitable

energy alternatives to nuclear fission.energy alternatives to nuclear fission. b. Yes. Nuclear fission is too expensive and b. Yes. Nuclear fission is too expensive and

produces large quantities of very dangerous produces large quantities of very dangerous radioactive wastes. radioactive wastes.

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