nuclear energy

1. Nuclear EnergyNuclear Energy

2. NUCLEAR ENERGYNUCLEAR ENERGY
 When isotopes ofWhen isotopes of
uranium anduranium and
plutonium undergoplutonium undergo
controlledcontrolled nuclearnuclear
fissionfission, the resulting, the resulting
heat is used toheat is used to
produce steam thatproduce steam that
spins turbines tospins turbines to
generate electricitygenerate electricity

3. NUCLEAR ENERGYNUCLEAR ENERGY
 Light water reactorsLight water reactors – most common (100%– most common (100%
in U.S., 85% worldwide)in U.S., 85% worldwide)

Uranium ore mined, enriched, made into pelletsUranium ore mined, enriched, made into pellets

Fuel rodsFuel rods – closed pipes with fuel pellets packed– closed pipes with fuel pellets packed
together in core of nuclear reactortogether in core of nuclear reactor

Pellets contain uranium dioxide fuel - 97%Pellets contain uranium dioxide fuel - 97%
nonfissionable uranium-238 and 3% fissionablenonfissionable uranium-238 and 3% fissionable
uranium-235uranium-235

Control rodsControl rods – move in and out of core to absorb– move in and out of core to absorb
neutrons and regulate rate of fissionneutrons and regulate rate of fission

4. Fig. 16-16, p. 372
Small amounts of
radioactive gases
Uranium fuel
input (reactor
core)
Control rods
Containment 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 Condenser
Periodic removal and
storage of radioactive
wastes and spent fuel
assemblies
Periodic removal
and storage of
radioactive liquid
wastes
Water source (river,
lake, ocean)

5. NUCLEAR ENERGYNUCLEAR ENERGY
 CoolantCoolant – (often water) keeps core from– (often water) keeps core from
melting downmelting down
 Water from nearby water bodyWater from nearby water body
 Waste heat released to troposphere – coolingWaste heat released to troposphere – cooling
towerstowers
 Containment shellContainment shell – around core – steel and– around core – steel and
concrete – to keep radioactive material in andconcrete – to keep radioactive material in and
protect from weather, etc.protect from weather, etc.

6. How Nuclear Energy Works

7. NUCLEAR FUEL CYCLENUCLEAR FUEL CYCLE
 Nuclear fuel cycleNuclear fuel cycle – all activities associated– all activities associated
with getting electricity from nuclear fuelwith getting electricity from nuclear fuel

Mining uraniumMining uranium

Processing and enriching uranium into fuelProcessing and enriching uranium into fuel

Building and running nuclear power plantBuilding and running nuclear power plant

Using fuel in reactorUsing fuel in reactor

Storing radioactive wasteStoring radioactive waste

Decommissioning power plant and storingDecommissioning power plant and storing
radioactive partsradioactive parts

8. NUCLEAR FUEL CYCLENUCLEAR FUEL CYCLE

9. NUCLEAR FUEL CYCLENUCLEAR FUEL CYCLE

10. NUCLEAR ENERGYNUCLEAR ENERGY
 After 3 – 4 years inAfter 3 – 4 years in
reactor,reactor, spentspent fuel rodsfuel rods
removed – stored in aremoved – stored in a
deep pool of waterdeep pool of water
contained in a steel-linedcontained in a steel-lined
concrete containerconcrete container

11. NUCLEAR ENERGYNUCLEAR ENERGY
 After rods cool – sometimes moved toAfter rods cool – sometimes moved to drydry
caskscasks made of steel or concretemade of steel or concrete

Vulnerable to terrorismVulnerable to terrorism

12. NUCLEAR ENERGYNUCLEAR ENERGY
 Some waste can be reprocessed – but resultSome waste can be reprocessed – but result
(plutonium) can be used for weapons –(plutonium) can be used for weapons –
stopped in U.S.stopped in U.S.
 Scientists disagree about the best methodsScientists disagree about the best methods
for long-term (thousands of years) storage offor long-term (thousands of years) storage of
high-level radioactive waste:high-level radioactive waste:

Bury it deep underground – cheapest and easiestBury it deep underground – cheapest and easiest

Shoot it into spaceShoot it into space

Bury it in the Antarctic ice sheetBury it in the Antarctic ice sheet

Bury it in the deep-ocean floor that is geologicallyBury it in the deep-ocean floor that is geologically
stablestable

Change it into harmless or less harmful isotopesChange it into harmless or less harmful isotopes

13. NUCLEAR ENERGYNUCLEAR ENERGY
 Long-term storage – storing highlyLong-term storage – storing highly
radioactive wastes for 10,000 – 240,000radioactive wastes for 10,000 – 240,000
yearsyears
 Yucca Mountain Nuclear WasteYucca Mountain Nuclear Waste
RepositoryRepository – Nevada – deep geological– Nevada – deep geological
repository to store spent nuclear fuel andrepository to store spent nuclear fuel and
other highly radioactive waste – abandonedother highly radioactive waste – abandoned
in 2010in 2010

Too expensive, too small, rock fractures,Too expensive, too small, rock fractures,
earthquakes, politicsearthquakes, politics
 Wastes stored at facilitiesWastes stored at facilities

15. NUCLEAR ENERGYNUCLEAR ENERGY
 Dealing with old nuclear power plants:Dealing with old nuclear power plants:

Decommission or retire the power plantDecommission or retire the power plant

Dismantle the plant and safely store theDismantle the plant and safely store the
radioactive materialsradioactive materials

Enclose the plant behind a physical barrier withEnclose the plant behind a physical barrier with
full-time security until a storage facility has beenfull-time security until a storage facility has been
builtbuilt

Enclose the plant in a concrete-steel tombEnclose the plant in a concrete-steel tomb
• Monitor this for thousands of yearsMonitor this for thousands of years

16. Nuclear Energy and Global WarmingNuclear Energy and Global Warming
 May reduce dependence on fossil fuels a bitMay reduce dependence on fossil fuels a bit
– therefore reducing CO– therefore reducing CO22
 But during construction (cement) andBut during construction (cement) and
decommissioning – huge amounts of COdecommissioning – huge amounts of CO22 areare
producedproduced

17. What Happened to Nuclear Power?What Happened to Nuclear Power?
 After about 60 years of development andAfter about 60 years of development and
enormous government subsidies, nuclearenormous government subsidies, nuclear
power has not lived up to its promisepower has not lived up to its promise
because:because:

Multi billion-dollar construction costsMulti billion-dollar construction costs

Higher operation costs and more malfunctionsHigher operation costs and more malfunctions
than expectedthan expected

Poor managementPoor management

Public concerns about safety (accidents andPublic concerns about safety (accidents and
terrorism) and stricter government safetyterrorism) and stricter government safety
regulations (they are very safe while operating)regulations (they are very safe while operating)

18. What Happened to Nuclear Power?What Happened to Nuclear Power?
 Nuclear releases little CONuclear releases little CO22 during operationduring operation

Many environmentalists began to re-examineMany environmentalists began to re-examine
nuclearnuclear

Fukushima DaiichiFukushima Daiichi nuclear disaster – Japan 2011nuclear disaster – Japan 2011
– after tsunami – equipment failure, loss of coolant– after tsunami – equipment failure, loss of coolant
accident, meltdown – second worst nuclearaccident, meltdown – second worst nuclear
disaster after Chernobyldisaster after Chernobyl

Environmentalists reconsidered support for nuclearEnvironmentalists reconsidered support for nuclear

20. Case Study: The Chernobyl NuclearCase Study: The Chernobyl Nuclear
Power Plant AccidentPower Plant Accident
 ChernobylChernobyl – world’s worst nuclear power– world’s worst nuclear power
plant accident – 1986, Ukraineplant accident – 1986, Ukraine
 Caused by poor reactor design & humanCaused by poor reactor design & human
errorerror
 By 2005, 56 people died from radiationBy 2005, 56 people died from radiation

4,000 more are expected to die from thyroid4,000 more are expected to die from thyroid
cancer and leukemiacancer and leukemia

350,000 abandoned homes350,000 abandoned homes

21. Chernobyl:
The World’s Worst
Nuclear Disaster

22. Case Study: Three Mile IslandCase Study: Three Mile Island
Nuclear Power Plant AccidentNuclear Power Plant Accident
 Three Mile IslandThree Mile Island – 1979 near Harrisburg,– 1979 near Harrisburg,
PA – partial meltdown, worst commercial U.S.PA – partial meltdown, worst commercial U.S.
nuclear accidentnuclear accident

Turning point in development of nuclear powerTurning point in development of nuclear power

23. Case Study: Shoreham NuclearCase Study: Shoreham Nuclear
Power PlantPower Plant
 Shoreham, LI – completed in 1984,Shoreham, LI – completed in 1984,
opposition after Three Mile Island, pooropposition after Three Mile Island, poor
evacuation, never opened, high electric billsevacuation, never opened, high electric bills

25. NUCLEAR ENERGY ANDNUCLEAR ENERGY AND
SECURITYSECURITY
 Terrorists could attack nuclear power plants,Terrorists could attack nuclear power plants,
especially poorly protected pools and casksespecially poorly protected pools and casks
that store spent nuclear fuel rodsthat store spent nuclear fuel rods
 Terrorists could wrap explosives aroundTerrorists could wrap explosives around
small amounts of radioactive materials thatsmall amounts of radioactive materials that
are fairly easy to get, detonate such dirtyare fairly easy to get, detonate such dirty
bombs, and contaminate large areas forbombs, and contaminate large areas for
decadesdecades

26. New and Safer ReactorsNew and Safer Reactors
 Advanced light-water reactors (ALWRs) –Advanced light-water reactors (ALWRs) –
metldowns and radioactive emissions almostmetldowns and radioactive emissions almost
impossibleimpossible

27. NUCLEAR ENERGYNUCLEAR ENERGY
 Nuclear fusionNuclear fusion – nuclear change in which– nuclear change in which
two isotopes are forced together releasingtwo isotopes are forced together releasing
energyenergy

No risk of meltdown or radioactive releasesNo risk of meltdown or radioactive releases

May also be used to breakdown toxic materialMay also be used to breakdown toxic material

Still in laboratory stagesStill in laboratory stages