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Chapter 12Chapter 12Nuclear EnergyNuclear Energy
Overview of Chapter 12Overview of Chapter 12
Introduction to Nuclear PowerIntroduction to Nuclear Power Nuclear FissionNuclear Fission Pros and Cons of Nuclear EnergyPros and Cons of Nuclear Energy Safety Issues at Power PlantsSafety Issues at Power Plants Radioactive WasteRadioactive Waste Future of Nuclear PowerFuture of Nuclear Power
Introduction to Nuclear Introduction to Nuclear EnergyEnergy Nuclear Energy - Nuclear Energy -
the energy released the energy released by nuclear fission or by nuclear fission or fusionfusion
Henri BecquerelHenri Becquerel Marie Curie (right)Marie Curie (right) Ernest RutherfordErnest Rutherford
Introduction to Nuclear Introduction to Nuclear EnergyEnergy Nuclear energyNuclear energy
Energy released by nuclear fission or fusionEnergy released by nuclear fission or fusion Nuclear fissionNuclear fission
Splitting of an atomic nucleus into two Splitting of an atomic nucleus into two smaller fragments, accompanied by the smaller fragments, accompanied by the release of a large amount of energyrelease of a large amount of energy
Nuclear fusionNuclear fusion Joining of two lightweight atomic nuclei into Joining of two lightweight atomic nuclei into
a single, heavier nucleus, accompanied by a single, heavier nucleus, accompanied by the release of a large amount of energy the release of a large amount of energy
Atoms and RadioactivityAtoms and Radioactivity
Nucleus Nucleus Comprised of Comprised of
protons (+) and protons (+) and neutrons (neutral)neutrons (neutral)
Electrons (–) orbit Electrons (–) orbit around nucleusaround nucleus
Neutral atomsNeutral atoms Same # of Same # of
protons and protons and electronselectrons
Atoms and RadioactivityAtoms and Radioactivity
Atomic massAtomic mass Sum of the protons and neutrons in an Sum of the protons and neutrons in an
atomatom Atomic numberAtomic number
Number of protons per atomNumber of protons per atom Each element has its own atomic numberEach element has its own atomic number
IsotopeIsotope Atom where the number of neutrons is Atom where the number of neutrons is
greater than the number of protonsgreater than the number of protons
Radioactive IsotopeRadioactive Isotope
Unstable isotopeUnstable isotope Radioactive DecayRadioactive Decay
Emission of energetic particles or rays Emission of energetic particles or rays from unstable atomic nucleifrom unstable atomic nuclei
ExampleExample Uranium (U-235) decays over time to Uranium (U-235) decays over time to
lead (Pb-207)lead (Pb-207) Each isotope decays based on its Each isotope decays based on its
own half-lifeown half-life
Radioactive Isotope Half-Radioactive Isotope Half-liveslives
Nuclear FissionNuclear Fission
Nuclear Fuel Nuclear Fuel CycleCycle processes processes
involved in involved in producing the producing the fuel used in fuel used in nuclear reactors nuclear reactors and in disposing and in disposing of radioactive of radioactive (nuclear) wastes (nuclear) wastes
Nuclear FissionNuclear Fission
How Electricity is ProducedHow Electricity is Produced
Breeder Nuclear FissionBreeder Nuclear Fission
A type of nuclear fission in which A type of nuclear fission in which non-fissionable U-238 is converted non-fissionable U-238 is converted into fissionable Pu-239 into fissionable Pu-239
Pros and Cons of Nuclear Pros and Cons of Nuclear EnergyEnergy ProsPros
Less of an immediate environmental Less of an immediate environmental impact compared to fossil fuelsimpact compared to fossil fuels
Carbon-free source of electricityCarbon-free source of electricity May be able to generate H-fuelMay be able to generate H-fuel
ConsCons Generates radioactive wasteGenerates radioactive waste Many steps require fossil fuels (mining Many steps require fossil fuels (mining
and disposal)and disposal) ExpensiveExpensive
Pros and Cons of Nuclear Pros and Cons of Nuclear EnergyEnergy
Cost of Electricity from Cost of Electricity from Nuclear EnergyNuclear Energy
Cost is very highCost is very high 20% of US electricity is from Nuclear 20% of US electricity is from Nuclear
EnergyEnergy Affordable due to government subsidiesAffordable due to government subsidies
Expensive to build nuclear power Expensive to build nuclear power plantsplants Long cost-recovery timeLong cost-recovery time
Fixing technical and safety issues in Fixing technical and safety issues in existing plants is expensiveexisting plants is expensive
Safety Issues in Nuclear Safety Issues in Nuclear Power PlantsPower Plants
MeltdownMeltdown At high temperatures the metal encasing At high temperatures the metal encasing
the uranium fuel can melt, releasing the uranium fuel can melt, releasing radiation radiation
Probability of meltdown is lowProbability of meltdown is low Public perception is that nuclear power Public perception is that nuclear power
is not safeis not safe Sites of major accidents:Sites of major accidents:
Three Mile IslandThree Mile Island Chornobyl (Ukraine)Chornobyl (Ukraine)
Three-Mile IslandThree-Mile Island
1979 - most serious reactor accident in 1979 - most serious reactor accident in USUS
50% meltdown of reactor core50% meltdown of reactor core Containment building kept radiation from Containment building kept radiation from
escapingescaping No substantial environmental damageNo substantial environmental damage No human casualtiesNo human casualties
Elevated public apprehension of Elevated public apprehension of nuclear energynuclear energy Led to cancellation of many new plants in Led to cancellation of many new plants in
USUS
ChornobylChornobyl
1986 - worst 1986 - worst accident in historyaccident in history
1 or 2 explosions 1 or 2 explosions destroyed the destroyed the nuclear reactornuclear reactor Large amounts of Large amounts of
radiation escaped radiation escaped into atmosphereinto atmosphere
Spread across Spread across large portions of large portions of EuropeEurope
ChornobylChornobyl
Radiation spread was unpredictable Radiation spread was unpredictable and unevenand uneven
Death toll isDeath toll is
10,000–10,000–
100,000100,000
Nuclear Energy and Nuclear Nuclear Energy and Nuclear WeaponsWeapons
31 countries use nuclear energy to 31 countries use nuclear energy to create electricitycreate electricity
These countries have access to spent These countries have access to spent fuel needed to make nuclear fuel needed to make nuclear weaponsweapons
Safe storage and handling of these Safe storage and handling of these weapons is a concernweapons is a concern
Radioactive WastesRadioactive Wastes
Low-level radioactive waste Low-level radioactive waste Radioactive solids, liquids, or gases that Radioactive solids, liquids, or gases that
give off small amounts of ionizing give off small amounts of ionizing radiation radiation
High-level radioactive waste High-level radioactive waste Radioactive solids, liquids, or gases that Radioactive solids, liquids, or gases that
give off large amounts of ionizing give off large amounts of ionizing radiation radiation
Radioactive WastesRadioactive Wastes
Long term solution to wasteLong term solution to waste Deep geologic burial – Yucca MountainDeep geologic burial – Yucca Mountain As of 2004, site must meet EPA million As of 2004, site must meet EPA million
year standard (compared to previous year standard (compared to previous 10,000 year standard)10,000 year standard)
Possibilities:Possibilities: Above ground mausoleumsAbove ground mausoleums Arctic ice sheetsArctic ice sheets Beneath ocean floorBeneath ocean floor
Radioactive WasteRadioactive Waste
Temporary storage solutionsTemporary storage solutions In nuclear plant facility (require high In nuclear plant facility (require high
security)security) Under water storageUnder water storage Above ground concrete and steel casksAbove ground concrete and steel casks
Need approved permanent options Need approved permanent options soon.soon.
Case-In-Point Yucca Case-In-Point Yucca MountainMountain 70,000 tons of high-70,000 tons of high-level radioactive level radioactive wastewaste
Tectonic issues have Tectonic issues have been identifiedbeen identified
Decommissioning Nuclear Decommissioning Nuclear Power PlantsPower Plants Licensed to operate for 40 yearsLicensed to operate for 40 years
Several have received 20-year extensionsSeveral have received 20-year extensions Power plants cannot be abandoned Power plants cannot be abandoned
when they are shut downwhen they are shut down Three solutionsThree solutions
StorageStorage EntombmentEntombment Decommissioning (dismantling)Decommissioning (dismantling)
Attitudes Towards Nuclear Attitudes Towards Nuclear PowerPower
NIMBY - Not In My BackYardNIMBY - Not In My BackYard Citizens to not want a nuclear facility or Citizens to not want a nuclear facility or
waste disposal site near their homewaste disposal site near their home Dad- Decide, Announce, DefendDad- Decide, Announce, Defend
Pronuclear advocatesPronuclear advocates Based on the science, not fearsBased on the science, not fears
FusionFusion
Fuel= isotopes of hydrogenFuel= isotopes of hydrogen
FusionFusion
Way of the future?Way of the future? Produces no high-level wasteProduces no high-level waste Fuel is hydrogenFuel is hydrogen
ProblemsProblems It takes very high temperatures (millions It takes very high temperatures (millions
of degrees) to make atoms fuseof degrees) to make atoms fuse Confining the plasma after it is formedConfining the plasma after it is formed
Scientists have yet to be able to Scientists have yet to be able to create energy from fusioncreate energy from fusion